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Biomedical subjects

Jian Lu

Publications and source records attributed to Jian Lu.

At least 55 records · Page 3Linked to original sources
PubMed2005

[Cloning of ACE-2 gene encoding the functional receptor for the SARS coronavirus and its expression in eukaryotic cells].

OBJECTIVE: Angiotensin-converting enzyme 2 (ACE-2) has been identified as a functional receptor of severe acute respiratory syndrome coronavirus (SARS-CoV), so its gene was cloned and eukaryotic expressed for further insight into mechanisms in SARS-CoV entry and pathogenesis, as well as development of a safe and reliable neutralization assay for SARS-CoV. METHODS: Total RNA was extracted from right atrial tissue of a patient with right heart failure resected during a valvular replacement surgery by Trizol one-step method, and the full-length ACE-2 encoding gene was acquired by RT-nested-PCR. The ACE-2 encoding gene was then cloned into pcDNA4/HisMax-TOPO eukaryotic expression vector to construct the recombinant plasmid pcDNA4/ ACE-2, which was then transfected into 293 T cell and ACE-2 eukaryotic transient expression was detected by Western Blot. Syncytia inhibition assay was established to detect SARS-CoV neutralizing antibody, and compared parallelly with SARS pseudovirus neutralization assay. RESULTS: The recombinant plasmid pcDNA4/ ACE-2 could express ACE-2 protein in eukaryotic cells and induce cell-cell fusion between S protein- and ACE2-expressing cells. This cell-cell fusion assay could be used to detect SARS-CoV neutralizing antibody. CONCLUSION: SARS-CoV receptor ACE-2 gene was successfully cloned and eukaryotic expressed, and used to establish syncytia inhibition assay for SARS-CoV neutralizing antibody assay.

Angiotensin-Converting Enzyme 2↗
PubMed2004

Knockdown of glucocorticoid receptor expression by RNA interference promotes cell proliferation in murine macrophage RAW264.7 cells.

It is well documented that glucocorticoids (GC) promote arrest in the G1-S transition of the cell cycle in many cell types, resulting in a decrease in proliferation. However, the relationship between glucocorticoid receptor (GR) and the cell-cycle regulation remains unclear. Suppression of GR is important for exploring GR dependent processes. This study applied RNA interference targeting GR to the murine macrophage RAW264.7 cells. Transient transfection of the GR-siRNA expression vector reduced GR synthesis as measured on mRNA and protein level by RT-PCR and Western blot. GR-siRNA also depressesed GR transcriptional activity. A cell line [RAW-(GR-)] stably transfected with GR-siRNA expression vector was then established, the decreased GR level in this cell line was confirmed by Western blot. MTT assay showed RAW-(GR-) cells grew faster than control cells, which indicated that knockdown of GR promoted cell proliferation in macrophages. Further studies showed decreased p27 expression, increased PKC-alpha expression and enhanced basal and LPS-induced NF-kappaB activity in RAW-(GR-) cells as compared to the RAW-control cells. In contrast, virtually no change in p21, ERK1/2 and p38 expression was detected. In conclusion, these results indicate that GR itself is an inhibitor of cell proliferation in RAW264.7 cell line. This effect may be associated with the decreased expression of p27, the increased expression of PKC-alpha, and the activation of NF-kappaB. As all the experiments are carried out in GC free or serum-free medium, this study also shows the possibility for GR to have some constitutive functions, which are independent on GC activation.

Animals↗
PubMed2004

Is optimal solution of every NP-complete or NP-hard problem determined from its characteristic for DNA-based computing.

Cook's Theorem [Cormen, T.H., Leiserson, C.E., Rivest, R.L., 2001. Introduction to Algorithms, second ed., The MIT Press; Garey, M.R., Johnson, D.S., 1979. Computer and Intractability, Freeman, San Fransico, CA] is that if one algorithm for an NP-complete or an NP-hard problem will be developed, then other problems will be solved by means of reduction to that problem. Cook's Theorem has been demonstrated to be correct in a general digital electronic computer. In this paper, we first propose a DNA algorithm for solving the vertex-cover problem. Then, we demonstrate that if the size of a reduced NP-complete or NP-hard problem is equal to or less than that of the vertex-cover problem, then the proposed algorithm can be directly used for solving the reduced NP-complete or NP-hard problem and Cook's Theorem is correct on DNA-based computing. Otherwise, a new DNA algorithm for optimal solution of a reduced NP-complete problem or a reduced NP-hard problem should be developed from the characteristic of NP-complete problems or NP-hard problems.

Algorithms↗
PubMed2004

[The contrast study between single and double balloon bilateral dilatation of kyphoplasty].

OBJECTIVE: To contrast single and double balloon-inflated kyphoplasty for vertebral compression fractures (VCFs) and evaluate its clinical efficacy. METHODS: From May 2000 to May 2004, 90 consecutive procedures were performed in 58 patients who suffered from painful vertebral compression fractures, transferring tumour and angioma. Ninety vertebrae were inflated while 62 as A group were double balloon and 28 as B group were single balloon, fracture reduction and bone cement augmentation. Preoperative and postoperative symptom levels, variables, complications were recorded and the vertebral height and Cobb angle were measured and analyzed. RESULTS: All patients' pain was alleviated or disappeared without syndrome, and the vertebral height and Cobb angle of both groups were improved. The average recovery rate was 72.6% (22.9% approximately 100%), Cobb angle from 17.9 degrees (3.1 degrees approximately 31.6 degrees ) were corrected to 9.6 degrees (0.6 degrees approximately 28.2 degrees ), the average angle was 8.7 degrees (0.3 degrees approximately 27.2 degrees ), and the contrast between preoperative and postoperative showed obvious differences (P <0.001). The average recovery rate of A group was 77.6% (55.3% approximately 100%), B group was 64.3% (22.9% approximately 100%). The average postoperative Cobb angle of A group was 9.9 degrees (0.3 degrees approximately 27.2 degrees ), B group was 8.6 degrees (0.6 degrees approximately 19.8 degrees ) (P >0.05). CONCLUSIONS: As a promising minimally invasive surgery, balloon kyphoplasty can provide early relief of pain and improve the function as well as spinal alignment in treatment of painful compression fracture owing to recovering the vertebral height and Cobb angle of the vertebral body. Single balloon-inflated kyphoplasty can improve VCFs as double balloon.

Adult↗
PubMed2004

A universal evolutionary index for amino acid changes.

Different nonsynonymous changes may be under different selective pressure during evolution. Of the 190 possible interchanges among the 20 amino acids, only 75 can be attained by a single-base substitution. An evolutionary index (EI) can be empirically computed for each of the 75 elementary changes as the likelihood of substitutions, relative to that of synonymous changes. We used 280, 1,306, 2,488, and 309 orthologous genes from primates (human versus Old World monkey), rodents (mouse versus rat), yeast (S. cerevisiae versus S. paradoxus), and Drosophila (D. melanogaster versus D. simulans), respectively, to estimate the EIs. In each data set, EI varies more than 10-fold, and the correlation coefficients of EIs from the pairwise comparisons are high (e.g., r = 0.91 between rodent and yeast). The high correlations suggest that the amino acid properties are strong determinants of protein evolution, irrespective of the identities of the proteins or the taxa of interest. However, these properties are not well captured in conventional measures of amino acid exchangeability. We, therefore, propose a universal index of exchange (U): for any large data set, its EI can be expressed as U*R, where R is the average Ka/Ks for that data set. The codon-based, empirically determined EI (i.e., U*R) makes much better predictions on protein evolution than do previous methods.

Amino Acids↗
PubMed2004

Mathematical modeling for prediction of endo-xylanase activity and arabinoxylans concentration during mashing of barley malts for brewing.

A mathematical model describing the degradation of arabinoxylans by endo-xylanase during mashing process was developed. Endo-xylanase activities and arabinoxylans concentrations in laboratory scale mashing process at different temperature profiles were measured and then used for identifying the model parameters for Harrington barley malt. The modeling errors range for the final concentration of arabinoxylans in wort was -4% to +11.9%. The model developed was also used for predicting the other three different malts mashing processes in laboratory scale, and the prediction errors ranged from -9.5% to +13.6%. The model prediction accuracy for industrial scale mashing process was lower than that in laboratory scale. The simulation results showed that, a lower concentration of arabinoxylans could be achieved when maintaining the mashing-in at 45 degrees C and prolonging the mashing-in time.

Computer Simulation↗
PubMed2004

Effect of transforming growth factor-beta on activity of connective tissue growth factor gene promoter in mouse NIH/3T3 fibroblasts.

AIM: To investigate the regulatory mechanism of transforming growth factor-beta on activity of connective tissue growth factor promoter in mouse NIH/3T3 fibroblasts. METHODS: The regulation fragment of the 5' flanking region of the human CTGF gene was linked to pGL3-Basic vector, a firefly luciferase reporter construct without promoter. The recombinant plasmid pCTGF-luc was transiently transfected to NIH/3T3 fibroblasts. The activity of CTGF promoter after treatment of TGF-beta(1) and MAPK pathway inhibitors were assayed with luciferase reporter gene assay system. RESULTS: TGF-beta(1)-induced increase of CTGF promoter activity was concentration-dependent, with a plateau at 5 microg/L by 2.67-fold vs control (P<0.05). The TGF-beta(1) stimulation of CTGF promoter activity was time-dependent, too. After exposure to TGF-beta(1) (5 microg/L), the maximal level of luciferase activity was reached at 12 h and maintained to 24 h by 2.76- and 2.20-fold vs control, respectively (P<0.05). Blockade of MAPK pathway with PD98059 (10 micromol/L), the MAP kinase kinase 1 inhibitor, and SB203580 (10 micromol/L), the p38 MAP kinase inhibitor, decreased basal and TGF-beta (1)-induced activation of CTGF promoter. However, inhibition of c-Jun-N-terminal kinase/stress-activated protein kinase by SP600125 (20 micromol/L) was without effect. CONCLUSION: TGF-beta(1) stimulated the transcriptional activity of CTGF gene promoter in NIH/3T3 fibroblasts in a dose- and time-dependent manner. MAPK pathway may play a role in the regulation of TGF-beta(1)-induced CTGF expression.

Animals↗
PubMed2003

The effects of inhibiting P18(INK4C) expression on the invasion of gastric adenocarcinoma cell line.

Using cDNA microarray with double dots of 4096 human genes, P18(INK4C), a member of CKI, was found down-regulated in a gastric adenocarcinoma metastatic cell line (RF-48), compared with the corresponding primary cancer cell line (RF-1), which implied that P18(INK4C) might be involved in cell invasion and metastatic progression of human gastric adenocarcinoma. Antisense RNA expression plasmid was applied to inhibit P18(INK4C) expression to study the effect of decreased P18(INK4C) expression on cell migration, invasion and proliferation ability and cell cycle of RF-1. Results showed that inhibition of P18(INK4C) expression could obviously enhance cell invasion ability of RF-1, but had little effect on its cell cycle and cell migration and proliferation ability. These results implied that P18(INK4C) might play a pivotal role in regulating cell invasion, rather than regulating cell cycle and proliferation in the progression of human gastric adenocarcinoma as expected before.

Adenocarcinoma↗
PubMed2003

Glucocorticoid modulation of extracellular signal-regulated protein kinase 1/2 and p38 in human ovarian cancer HO-8910 cells.

OBJECTIVE: To investigate the signaling pathway through testing the effects of dexamethasone (Dex) on the activation of the extracellular signal-regulated protein kinase 1/2 (ERK1/2) and p38 kinase (p38) in HO-8910 cells. METHODS: Activation of the ERK1/2 and p38 was detected by Western blotting using the antibodies against the total ERK1/2 and p38 mitogen-activated protein kinases (MAPKs) protein and the phosphorylated forms of them. RESULTS: Dex could suppress the activation of ERK1/2, while enhance the activation of p38 rapidly and strongly in a dose- and time- dependent manner. Neither effect could be blocked by RU486, the antagonist of glucocorticoid receptor (GR). CONCLUSION: Dex has rapid effects on the activation of ERK1/2 and p38, and these effects are not mediated by GR.

Cell Division↗
PubMed2003

[Study on the molecular mechanism of transferable multiple-antibiotic resistance in extended-spectrum beta-lactamase-producing clinical isolates].

OBJECTIVE: To investigate the molecular mechanism of transferable multiple-antibiotic resistance in extended-spectrum beta-lactamases (ESBLs) producing isolates. METHODS: Antibiotics susceptibility was tested by E-test method, and multi-resistance plasmids were screened and isolated by extracting transformant plasmids. Inserted gene Cassettes of class 1 integron were amplified and analyzed by polymerase chain reaction (PCR) and DNA sequencing. RESULTS: Eight of the nine ESBL-producing plasmids were found to comprise class 1 integron sequence, of them 7 harbored 1 or 2 antibiotic resistant gene cassettes which encoding resistance to aminoglycosides (aacA4, aadA2 or aadA5), trimethoprim (dhfrA12 or dfrA17), rifampicin (arr-3) and chloramphenicol (cmlA6). The function of these gene cassettes corresponded to the resistance profiles of their electro-transformants. CONCLUSION: Multi-resistance gene cassettes located on plasmids and mediated by class 1 integron may play an important role in causing the development and dissemination of multiple-antibiotic resistance in ESBL-producing clinical isolates.

Anti-Bacterial Agents↗
PubMed2003

[Sublethal effects of insecticides on fecundity of multicolored Asian ladybird Harmonia axyridis].

The effects of sublethal doses of 6 insecticides (imidacloprid, rotenone, fenvalerate, abamectin, pirimicarb and azadirachtin) on the fecundity of multicolored Asian ladybird Harmonia axyridis were determined respectively. The results showed that in all treatments, the daily average number of eggs per female ladybird was about 40-55. Ladybirds pretreated with imidacloprid by contact and feeding methods, and with rotenone by feeding method produced significantly fewer eggs, compared with control. But the accumulative oviposition of ladybirds pretreated with 6 insecticides at sublethal level was no significant differences, compared with untreated ladybirds. The hatching rates of the eggs laid by ladybirds pretreated with 6 insecticides by two methods were all lower than that of control. The accumulative survivals from egg to pupal stage of all treatments decreased significantly. The developmental duration from egg to pupa of those treated with imidacloprid by two methods and with fenvalerate by contact method prolonged significantly, while that of those treated with rotenone by two methods and with fenvalerate, abamectin, pirimicarb, and azadirachtin by feeding method shortened obviously, but that of those treated with rotenone and abamectin by contact method had no differences with control. After the eggs were immersed with sublethal concentrations of imidacloprid, rotenone, fenvalerate and abamectin, the successful hatching rates were all lower than that of control, and the development periods prolonged clearly. The 1st instar larval survival rates of those treated with fenvalerate decreased significantly, and the survivals from 2nd instar larval to pupal stage also reduced to some extent. The total developmental duration of those treated with rotenone and fenvalerate prolonged significantly. These findings suggested that the effects of insecticides at low doses on the fecundity of ladybird were very complicated. The class, action mode, toxicity and exposure route of insecticides could affect the results of experiments.

Animals↗
PubMed2003

[Study of susceptibility and genotype characterization of plasmid-mediated class I cephalosporinase in gram-negative bacteria].

OBJECTIVE: To investigate the susceptibility and genotype characteristics of gram-negative bacteria producing plasmid-mediated class I cephalosporinase (AmpC beta lactamase) epidemic in Southern China. METHODS: A total of 1,187 clinical isolates of nonrepetive gram-negative bacteria were collected from different cities in Southern China. AmpC beta lactamase producing isolates were identified by cefoxitin three-dimensional test, and antimicrobial susceptibility test was identified by Kirby-Bauer agar diffusion test; plasmid conjugation, plasmid extraction, universal PCR for gene amplication of corresponding group was done, and the PCR products were sequenced subsequently. RESULTS: The positive rate of cefoxitin three-dimensional test in gram-negative bacteria was 5.9% (70/1,187), and the prevalence of plasmid-mediated AmpC beta lactamase was: E. coli: 4.2% (19/451), Klebsiella: 4.7% (16/339), Enterobacter: 2.1% (4/190), Alcaligenes: 5.3% (1/19), Acinetobacter: 2.2% (1/45) and the total positive rate was: 3.5% (41/1,187). The susceptibility test showed that compared with the clinical isolates, the transconjugations remained resistance to cephamycins and ampicillin, and susceptible to cefepime and imipenem. PCR amplication and sequencing confirmed them to be bla(DHA-1) gene and bla(ACT-1) gene, and they were mainly distributed in Klebsiella and Escherichia. CONCLUSIONS: DHA-1 and ACT-1 were the most common genotypes in plasmid-mediated AmpC beta-lactamase produced by clinical isolates in Southern China. Fourth-generation cephalosporins and carbapenems could be better choices for the treatment of infection caused by AmpC betalactamase producers.

Bacterial Proteins↗
PubMed2003

[Antigencity identification of recombinant hepatitis E virus ORF2 protein expressed in Pichia pastoris].

BACKGROUND: To determine the antigenicity of recombinant hepatitis E virus ORF2 (rHEV ORF2) protein expressed in Pichia pastoris (P. pastoris). METHODS: By using the rHEV ORF2 protein from E.coli as control, an indirect ELISA was adopted to identify the sensitivity, specificity and stability of rHEV ORF2 protein from P. pastoris in detection of HEV IgM and IgG antibody in sera from patients with hepatitis E. The reactivity of the rHEV ORF2 against 5 HEV ORF2 monoclonal antibodies (McAbs) was also tested. RESULTS: The minimum concentration of coated antigen with which HEV IgG could be detected was 12.5 ng/ml, while the highest serum dilution to detect both IgM and IgG antibodies against HEV was 1:5 120. No cross-reaction was found with sera from patients with any other types of hepatitis. The 37 degree C acceleration test showed that the rORF2 was highly stable within 12 months at 4 degrees C. The 5 HEV ORF2 McAbs showed better reaction with the rORF2 from P. pastoris, especially that 4B2, 2E2, whose reaction against the rORF2 were 125 and 25 times respectively higher than that of rORF2 from E.Coli. CONCLUSION: There may be more extensive conformational epitopes in the rHEV ORF2 from P. pastoris. The excellent antigenicity, sensitivity and stability suggest that it can be served as a new candidate antigen for the development of diagnostic reagents of hepatitis E.

Gene Expression↗
PubMed2002

Evaluation of nanostructured carbonated hydroxyapatite coatings formed by a hybrid process of plasma spraying and hydrothermal synthesis.

Carbonated hydroxyapatite (CHA) coatings on a titanium alloy were prepared by hydrothermal synthesis of precursors plasma-sprayed with brushite as a raw powder. The structures, residual stresses, and bond strengths of the precursors and CHA coatings were investigated. The results showed that the sprayed precursors consisted of beta-Ca(2)P(2)O(7), alpha-Ca(3)(PO(4))(2), and CaHPO(4), whereas the CHA coatings exhibited a unique phase construction, nanostructured and needle-like crystals, and a fairly low tensile residual stress. The bond strength of a CHA coating 200 microm thick was 15 MPa, equivalent to that of a plasma-sprayed hydroxyapatite (HA) coating. The evaluation of the CHA coatings was performed together with that of plasma-sprayed HA coatings immersed in distilled water. The dissolution and bond-strength degradation of the CHA coatings were much lower than those of the plasma-sprayed HA coatings.

Carbon↗
PubMed2002

Rat Genome Database (RGD): mapping disease onto the genome.

The Rat Genome Database (RGD, http://rgd.mcw.edu) is an NIH-funded project whose stated mission is 'to collect, consolidate and integrate data generated from ongoing rat genetic and genomic research efforts and make these data widely available to the scientific community'. In a collaboration between the Bioinformatics Research Center at the Medical College of Wisconsin, the Jackson Laboratory and the National Center for Biotechnology Information, RGD has been created to meet these stated aims. The rat is uniquely suited to its role as a model of human disease and the primary focus of RGD is to aid researchers in their study of the rat and in applying their results to studies in a wider context. In support of this we have integrated a large amount of rat genetic and genomic resources in RGD and these are constantly being expanded through ongoing literature and bulk dataset curation. RGD version 2.0, released in June 2001, includes curated data on rat genes, quantitative trait loci (QTL), microsatellite markers and rat strains used in genetic and genomic research. VCMap, a dynamic sequence-based homology tool was introduced, and allows researchers of rat, mouse and human to view mapped genes and sequences and their locations in the other two organisms, an essential tool for comparative genomics. In addition, RGD provides tools for gene prediction, radiation hybrid mapping, polymorphic marker selection and more. Future developments will include the introduction of disease-based curation expanding the curated information to cover popular disease systems studied in the rat. This will be integrated with the emerging rat genomic sequence and annotation pipelines to provide a high-quality disease-centric resource, applicable to human and mouse via comparative tools such as VCMap. RGD has a defined community outreach focus with a Visiting Scientist program and the Rat Community Forum, a web-based forum for rat researchers and others interested in using the rat as an experimental model. Thus, RGD is not only a valuable resource for those working with the rat but also for researchers in other model organisms wishing to harness the existing genetic and physiological data available in the rat to complement their own work.

Animals↗