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Biomedical subjects

Lin Zhang

Publications and source records attributed to Lin Zhang.

At least 199 records · Page 11Linked to original sources
PubMed2005

[Effect of RNAi-mediated gene silencing of C-erbB-2 on proliferation of lung adenocarcinoma cell line calu-3].

BACKGROUND & OBJECTIVE: C-erbB-2 gene is amplified or overexpressed in breast cancer, ovarian cancer, and lung cancer, and is related with enhanced malignancy and metastatic ability, intrinsic chemoresistance, and poor prognosis of tumors. RNA interfering (RNAi), a new genetic technique, can efficiently and specifically suppress gene expression. This study was to investigate the effect of small interfering RNA (siRNA)-mediated gene silencing of C-erbB-2 on proliferation of human lung adenocarcinoma cell line calu-3. METHODS: C-erbB-2 siRNA was transfected into calu-3 cells; cell morphology was observed under light microscope. The mRNA and protein levels of C-erbB-2 were detected by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry (FCM). The proliferation of calu-3 cells was assessed by MTT assay. Cell cycle and apoptosis were analyzed by FCM. RESULTS: C-erbB-2 siRNA down-regulated the mRNA and protein levels of C-erbB-2 in calu-3 cells; 48 h after transfection of C-erbB-2 siRNA, the protein level of C-erbB-2 was markedly decreased. The positive rate of C-erbB-2 was significantly lower in C-erbB-2 siRNA group than in untransfected group, empty vector group, and nonspecific siRNA group [(25.04+/-1.56)% vs. (98.24+/-2.23)%, (95.67+/-1.98)%, and (94.79+/-0.87)%, P < 0.01]. C-erbB-2 siRNA inhibited proliferation of calu-3 cells: G(0)/G(1) phase proportion of C-erbB-2 siRNA group was significantly higher than that of untransfected group [(56.6+/-3.6)% vs. (45.5+/-3.2)%, P < 0.01]. C-erbB-2 siRNA also enhanced cell apoptosis. CONCLUSION: Specific siRNA targeting C-erbB-2 can effectively inhibit C-erbB-2 expression and proliferation of calu-3 cells.

Adenocarcinoma↗
PubMed2005

[Expression and purification of GST-Rta fusion protein from EB virus and preparation of the polyclonal antibody against GST-Rta].

OBJECTIVE: To obtain the recombinant fusion proteins GST-Rta185 and GST-Rta150 from EB virus and prepare two Rta protein specific polyclonal antibodies, respectively. METHODS: Plasmids pGEX-R1501, pGEX-R1851 and pGEX-5X-3 were separately transformed into Escherichia coli BL21 (DE3). Expressions of the recombinant proteins R150-GST, R185-GST and free GST were induced by 0.1 mmol/L IPTG in LB medium. The expressed proteins were purified from lysates with Glutathione Sepharose 4B. Purified proteins were mixed with Freund's adjuvant and then were used to immunize rabbits. RESULTS: High levels of expression of target proteins were detected in the lysates and the purified proteins were obtained by affinity chromatography with Glutathione Sepharose 4B. Western blot and ELISA analysis suggested that the polyclonal antibodies against GST-R185 and GST-R150 were specific. CONCLUSION: The antiserums have good specificity. They are important for the research on Rta fusion proteins from EB virus and for the diagnosis or treatment of EB virus associated diseases.

Animals↗
PubMed2005

[Association between phospholamban gene mutation and dilated cardiomyopathy in the Chengdu area].

OBJECTIVE: To find out whether phospholamban (PLN) is the virulence gene of dilated cardiomyopathy (DCM) in the Chinese of Chengdu. METHODS: DNA was isolated from 89 hospitalized unrelated patients with DCM and 110 healthy Chinese Hans as controls. The PLN mutations was screened by polymerase chain reaction (PCR)-single strand conformation polymorphisms (SSCP) and nucleotide sequence analysis. RESULTS: In polyacrylamide gel lectrophoresis, no abnormal conformer was found in the two groups. In DNA sequence, no C --> T missense mutation at nucleotide 25 was identified in the DCM patients and the controls. Meanwhile, T --> G missense mutation at nucleotide 116 was not found in the affected individuals and in the controls. CONCLUSION: No PLN gene mutation was found in patients with DCM in Chengdu. This result indicated that PLN gene mutation may not be a common cause for DCM in the Chinese population in Chengdu.

Base Sequence↗
PubMed2005

[Species identification of biological samples by amplifying intron 8 of the TP53 gene].

OBJECTIVE: To identify the species of biological samples by amplifying intron 8 of the TP53 gene. METHODS: Collected the bloodstains or muscle tissues of 14 kinds of common animals and human. DNA were quantified after extraction. The PCR amplification products were analyzed by PAGE and silver staining. RESULTS: The human and monkey have one amplification band of 460 bp while the eel, fish, frog, duck, rabbit, cat, mouse, cavy, pig, ox and sheep could amplify different unspecial bands. No amplification products were found in chicken and dog. CONCLUSION: The method of species identification by amplifying intron 8 of the TP53 gene is simple and sensitive.

Animals↗
PubMed2005

[Construction and functional analysis of a novel eukaryotic expression plasmid of recombinant immunotoxin DT390-Rantes].

OBJECTIVE: To construct a novel eukaryotic expression plasmid for recombinant immunotoxin DT390-Rantes and perform preliminary analysis of its function. METHODS: The gene fragment coding for Rantes was obtained from the liver tissues of C57BL/6 mice using RT-PCR, and inserted into the eukaryotic expression plasmid SRalpha containing DT390 gene to construct the recombinant plasmid DT390-Rantes-SRalpha, which was transformed into E. coli JM109, followed by selection of the positive clones containing the target inserts. The eukaryotic expression plasmid was analysed by PCR, restriction endonuclease digestion and DNA sequencing. The recombinance plasmid DT390-Rantes-SRalpha was transfected into NIH3T3 cells and its expression was observed by immunofluorescence detection. The activity of the expressed DT390-Rantes in vitro was evaluated by MTT assay. RESULTS: The gene fragment of Rantes was correctly inserted into the eukaryotic expression plasmid SRalpha as verified by restriction endonuclease digestion and DNA sequencing, and could be expressed in NIH3T3 cells. MTT assay confirmed that the expression product DT390-Rantes could kill activated T cells in vitro. CONCLUSIONS: The recombinant eukaryotic expression plasmid DT390-Rantes-SRalpha is successfully constructed and expressed in eukaryotic cells. The expressed product can specifically kill activated T cells in vitro.

Animals↗
PubMed2005

[Clinical analysis of the pathogenesis of mycoplasma pneumonia in children].

OBJECTIVE: To study the clinical features and immune-mediated pathogenesis of mycoplasma pneumonia (MP) in children. METHODS: The DNA of mycoplasma in nasopharyngeal swabs was detected by PCR in 485 children with respiratory tract infection, and serum circulating immune complex (CIC), IgG, IgM, MP IgM, and CH50 were measured on the same day in 45 children with pneumonia. RESULTS: Significant difference was noted between the results of mycoplasma DNA PCR detection and those of serum IgM detection. The positivity rate of CIC was 44% in children with MP whereas that in the control group was only 10% (P<0.01). The levels of serum IgG and IgM in MP group was significantly higher and serum CH50 lower than those of the control group (P<0.05). CONCLUSION: Mycoplasma DNA detection facilitates early diagnosis and treatment of MP, whose pathogenesis in children may be involved in immune-mediated mechanism.

Adult↗
PubMed2005

[Infrared photostimulated luminescence and optical storage compares in alkaline earth sulphide doped with Mn].

The phosphors SrS: Eu and CaS: Eu doped with Mn were prepared by sulfurization flux method (SFM). Infrared photostimulated luminescence (PSL) of both the phosphors were measured. The PSL peak wavelength of SrS: Eu, Mn is 610 nm. Comparing the storage intensities, SrS has better optical properties. The doping of Mn2+ increases photon amount and improves the storage properties.

Calcium Compounds↗
PubMed2005

[Application and improvement of partial-least-squares in Fourier transform infrared spectroscopy].

Partial least squares(PLS) algorithm is an effective chemometric tool. It takes the advantages of multipal linear regression (MLR) and principal component regression (PCR), which makes Fourier transform infrared spectrometry (FTIR) more powerful and useful. Accompanied with increasing use of FTIR, the algorithm is modified and corrected under different circumstances. The applications of PLS to FTIR were mentioned. Improved algorithms were presented, such as moving windows PLS(MWPLS), robust PLS (RPLS), weighted PLS(WPLS), and non-linear PLS. Data pre-processing, selection of variable, noise elimination and non-linear model of PLS were introduced.

English Abstract↗
PubMed2005

[Advances in passive OP-FTIR].

As an OP-FTIR(Open Path FTIR) technology, passive OP-FTIR not only has the advantages of OP-FTIR, but also has the ability to collect data from any direction without prior background information. This technology allows mobile, fast, man-held and stand-off detection of hazardous chemical cloud.The present paper presents some developments of passive OP-FTIR, including high altitude atmospheric pollution detection, auto-detection of toxic cloud, hot gases detection (such as the determination of major combustion products in aircraft exhausts, remote sensing of smoke plumes, and remote sensing of volcano emissions), temperature and combustion products determination (including cloud temperature determination). The present paper also gives the application of passive OP-FTIR in the military. With the development of FTIR and computer science, more and more applications of OP-FTIR to environment supervision, aviation and space flight, engine exhausts, combustion and military will be fulfilled.

English Abstract↗
PubMed2005

[Determination of rare earth elements in trialkyl phoshine oxide (TRPO)-kerosene by ICP-AES].

The present paper describes the determination of rare earth elements (REEs) in 30% TRPO-kerosene by inductively coupled plasma atomic emission spectrometry (ICP-AES) with ethanol as diluent. The relative intensities of REEs vary slowly when the content of 30% TRPO-kerosene varies from 4% to 20%. The relative intensity of Ce increased with the contents of H2O increasing from 1% to 7%, but the other REEs did not vary. No effects on the relative intensities of REEs are seen when the concentration of HNCO3 varies from 0.065 to 0.315 mol x L(-1). The effects of Fe and Zr on the relative intensities of REEs are also investigated. The effects of Fe on the relative intensities of REEs are not obvious, but when the concentration of Zr is ten times larger than REEs, the effects are obvious. The method is applicable when the content of 30% TRPO-kerosene ranges from 4% to 20%, the limits of detection of La, Ce, Pr, Nd, Sm are 0.012, 0.040, 0.029, 0.040 and 0.021 microg x mL(-1) respectively, the RSD% is lower than 2%, and the relative error is lower than 3% when compared with the determination result of digestion. In contrast with digestion, this method is simple and rapid, and can accord with the requests of analysis.

English Abstract↗
PubMed2005

Relationships of Indoor, Outdoor, and Personal Air (RIOPA). Part I. Collection methods and descriptive analyses.

This study on the relationships of indoor, outdoor, and personal air (RIOPA) was undertaken to collect data for use in evaluating the contribution of outdoor sources of air toxics and particulate matter (PM) to personal exposure. The study was not designed to obtain a population-based sample, but rather to provide matched indoor, outdoor, and personal concentrations in homes that varied in their proximity to outdoor pollution sources and had a wide range of air exchange rates (AERs). This design allowed examination of relations among indoor, outdoor, and personal concentrations of air toxics and PM across a wide range of environmental conditions; the resulting data set obtained for a wide range of environmental pollutants and AERs can be used to evaluate exposure models. Approximately 100 households with residents who do not smoke participated in each of three cities in distinct locations expected to have different climates and housing characteristics: Elizabeth, New Jersey; Houston, Texas; and Los Angeles County, California. Questionnaires were administered to characterize homes, neighborhoods, and personal activities that might affect exposures. The concentrations of a suite of volatile organic compounds (VOCs) and carbonyl compounds, as well as the fraction of airborne particulate matter with a mass median aerodynamic diameter < or = 2.5 microm (PM2.5), were measured during continuous 48-hour sessions in which indoor, outdoor, and personal air samples were collected simultaneously. During the same 48-hour period, the AER (exchanges/hr; x hr(-1)) was determined in each home, and carbonyl compounds were measured inside vehicle cabins driven by a subset of the participants. In most of the homes, measurements were made twice, during two different seasons, to obtain a wide distribution of AERs. This report presents in detail the data collection methods, quality control measures, and initial analyses of data distributions and relations among indoor, outdoor, and personal concentrations. The results show that indoor sources dominated personal and indoor air concentrations of many measured VOCs and carbonyl compounds. For several measured species, personal concentrations were higher than either indoor or outdoor concentrations, indicating the presence of some sources closely related to personal activities. For some species there were no significant indoor sources in the majority of the homes; thus indoor concentrations were mainly determined by outdoor concentrations in these homes. The range of distributions of air concentrations for the measured VOCs, formaldehyde and acetaldehyde, PM2.5, and AERs were generally consistent with values reported previously in the literature. Thus associations derived from or models based on this data set that may link the influence of outdoor sources with indoor air concentrations of air toxics and PM2.5 can be relevant to other urban settings. The simultaneous measurements of indoor concentrations, outdoor concentrations, AERs, and room volumes allowed the use of a mass balance model, under the steady-state approximation, to mechanistically examine the relative contributions of indoor and outdoor sources to measured indoor concentrations on a home-by-home basis. Estimated indoor source strengths for VOCs and carbonyl compounds varied widely from home to home, consistent with the indoor-outdoor concentration patterns, as shown in scatter plots. The indoor source estimations agreed with published values for PM2.5 and with the general understanding of sources of VOCs and carbonyl compounds. The source strengths reported here, derived from hundreds of homes, are an important contribution to the literature on exposure to air toxics. For the first time for many compounds, these estimates present a cohesive set of measurements across a range of air toxics in paired indoor, outdoor, and personal samples along with AER and questionnaire results that can be used for future analyses of indoor air quality. The estimation of outdoor contributions to measured indoor concentrations provides insights about the relative importance of indoor and outdoor sources in determining indoor concentrations, the main determinant of personal exposure for most of the measured compounds. In this report simple statistical tests mainly of the pooled data were used to analyze differences by sampling site, emission source type, season, home type, and home age. Paired adult-child personal concentrations within the same home were also compared using the pooled data set. These analyses generated some intriguing results that warrant more in-depth investigation in the future.

Air Movements↗
PubMed2005

[Screening of a triazophos-degrading strain and pathway of its degradation].

A Triazophos-degrading strain, Klebsiella sp. E6, was identified by soil enrichment technology from the soil sampled from the vicinity of a factory manufacturing Triazophos (TAP). The nutrient requirement of the strain is simple. It can use TAP as the sole sources of carbon, nitrogen and phosphorus. Comparison of the degradation rates revealed that the strain degraded TAP most effectively when TAP was used as a sole nitrogen source. No inhibition effect occurred when TAP concentration was high as 1000 mg/L in the case of TAP was used as the sole nitrogen source. Analysis of the intermediates of TAP metabolism indicated that TAP is firstly hydrolyzed into 1-phenyl-3-hydroxy-1,2,4-triazole and O,O-diethyl phosphorothioic acid. 1-phenyl-3-hydroxy-1,2,4-triazole was further mineralized into inorganic compounds. A degradation pathway of TAP was proposed. The experiment results demonstrated that the strain has potential in biodegradation of TAP pollutions.

Biodegradation, Environmental↗
PubMed2004

RNA interference: a potential strategy for isoform-specific phosphatidylinositol 3-kinase targeted therapy in ovarian cancer.

Phosphatidylinositol 3-kinase (PI3-kinase) is a novel intracellular transducer involved in a wide range of cancer-associated signaling pathways, which comprises various isoforms and splice variants with distinct biologic activities and clinical implications. Especially, the class Ia PI3-kinase 110 kD catalytic subunit alpha (PIK3CA) is the most important isoform in tumorigenesis and possibly, tumor angiogenesis. Several strategies have been developed to block PI3-kinase for cancer therapy; however, the approach to target specific PI3-kinase isoform has not been explored to date. In the present study, we show that RNA interference (RNAi) through small interfering (siRNA) sequences targeting PIK3CA has potential applications in isoform-specific "knock-down" of PI3-kinase. This strategy provides a novel tool to study the function of various PI3-kinase isoforms and may contribute to isoform-specific targeting of PI3-kinase in human cancer.

Animals↗
PubMed2004

Transabdominal ultrasonography in preoperative staging of gastric cancer.

AIM: To investigate the value of transabdominal ultrasonography (US) in the preoperative staging of gastric cancer. METHODS: A total of 198 patients with gastric cancer underwent preoperatively transabdominal US, depth of tumor infiltration was assessed in 125 patients, and lymph node metastasis was assessed in 106 patients. RESULTS: The staging accuracy of transabdominal US was 55.6%, 75.0%, 87.3% and 71.1% in T1, T2, T3 and T4 carcinomas, respectively. The overall accuracy was 77.6%. The detection rate for pancreatic invasion and liver invasion was 77.4%, 71.4%, respectively. The sensitivity, specificity, accuracy of transabdominal US in assessment of lymph node metastasis were 77.6%, 64.1%, 72.6%, respectively. Various shapes such as round, ovoid, spindle were encountered in benign and malignant lymph nodes. Majority of both benign and malignant lymph nodes were hyperechoic and had a distinct border. Benign lymph nodes were smaller than malignant lymph nodes in length and width (P = 0.000, 0.005). Irregular shape, fusional shape, infiltrative signs, inhomogenous echo were seen mainly in malignant lymph nodes (P = 0.045, 0.006, 0.027, 0.006). CONCLUSION: Transabdominal US is useful for preoperative staging in gastric cancer, although it is difficult to differentiate benign from malignant lymph nodes.

Abdomen↗
PubMed2004

SMAC/Diablo-dependent apoptosis induced by nonsteroidal antiinflammatory drugs (NSAIDs) in colon cancer cells.

Nonsteroidal antiinflammatory drugs (NSAIDs) form a paradigm for the chemoprevention of cancer, preventing colonic tumor progression in both experimental animals and humans. However, the mechanisms underlying the antineoplastic effects of NSAIDs are currently unclear. We found that the mitochondrial second mitochondrial-derived activator of caspase (SMAC)/direct inhibitor of apoptosis protein-binding protein with low pI (Diablo) protein translocates into the cytosol during NSAID-induced apoptosis in colon cancer cells. When SMAC/Diablo is disrupted by homologous recombination and RNA interference in these cells, the NSAID-induced apoptosis is abrogated. Biochemical markers of apoptosis, such as caspase activation, cytosolic release of cytochrome c and apoptosis-inducing factor, and mitochondrial membrane potential change, are accordingly decreased. These results establish that SMAC/Diablo is essential for the apoptosis induced by NSAIDs in colon cancer cells.

Anti-Inflammatory Agents, Non-Steroidal↗