Biomedical subjects

Qing Zeng

Publications and source records attributed to Qing Zeng.

10 recordsLinked to original sources

PubMed2002

[Factors influencing pathogenicity of Collectotrichum gloeosporioides f.sp. veronicae to Veronica persica].

The effects of the characters of the fungus, the growing period of plants and environmental factors on the pathogenicity of Colletotrichum gloeosporioides f.sp. veronicae infecting Veronica persica were studied in pot experiments. The results showed that 1.08 x 10(8) spores.ml-1 suspension could kill the seedlings with two cotyledons within one week and cause old plants serious disease. 1 x 10(8) spores.ml-1 was optimal concentration and 1 or 2 weeks old was the best age of the spores for killing birdseye speedwell. The optimal temperature was 15-25 degrees C for the disease development. More than two days' dew exposure was required to kill the weed. However, the disease was also developed better when corn or soybean flour was added or the darkness period during dew exposure was prolonged.

Colletotrichum↗

PubMed2002

Enhanced antiangiogenic therapy of squamous cell carcinoma by combined endostatin and epidermal growth factor receptor-antisense therapy.

PURPOSE: We tested the combined effects of antiangiogenic endostatin and epidermal growth factor receptor (EGFR) antisense gene therapy on squamous cell carcinoma (SCC). EXPERIMENTAL DESIGN AND RESULTS: The 1483 cell line of human head and neck SCC (HNSCC) and SCC-VII/SF murine SCC cells was used to establish tumors in nude mice and immunocompetent C3H mice, respectively. Tumor-bearing mice were treated with endostatin (20 mg/kg/day, s.c.), liposomal EGFR-antisense expression plasmid (25 microg/mouse, three times/week, intratumoral), a combination of both agents, or liposomal EGFR-sense plasmid as a control. Endostatin or EGFR-antisense alone significantly, yet partially, inhibited the growth of 1483 and SCC-VII/SF tumors, and a combination of both treatments completely blocked tumor growth. Immunohistochemistry analysis demonstrated that a complete suppression of tumor angiogenesis was achieved by the combination treatment. Down-regulation of vascular endothelial growth factor was shown in EGFR-antisense-treated tumors. These results suggest that the EGFR-antisense treatment, in addition to its inhibitory activity on tumor cell proliferation, might have a synergistic effect with endostatin on SCC-induced angiogenesis. In vitro studies demonstrated that EGFR inhibition by antisense oligonucleotides or EGFR-specific tyrosine kinase inhibitor down-regulated the production of VEGF in HNSCC cells. Additional experiments demonstrated that these EGFR inhibition approaches also directly suppressed the growth of endothelial cells. CONCLUSION: A combination of endostatin and EGFR targeting strategies profoundly inhibited the angiogenesis and growth of SCC in vivo. EGFR-antisense therapy might have multiple inhibitory effects against both tumor cells and endothelial cells, leading to enhanced antitumor efficacy. Such a combination strategy might represent a novel and promising approach for HNSCC therapy.

Animals↗

PubMed2002

Using a neural network with flow cytometry histograms to recognize cell surface protein binding patterns.

Flow cytometric systems are being used increasingly in all branches of biological science including medicine. To develop analytic tools for identifying unknown molecules such as the antibodies that recognize different structure in the identical antigens, we explored use of a neural network in flow cytometry data comparison. Peak locations were extracted from flow cytometry histograms and we used the Marquardt backpropagation neural networks to recognize identical or similar binding patterns between antibodies and antigens based on the peak locations. The neural network showed 93.8% to 99.6% correct classification rates for identical or similar molecules. This suggests that the neural network technique can be useful in flow cytometry histogram data analysis.

Antibodies, Monoclonal↗

PubMed2002

Matching of flow-cytometry histograms using information theory in feature space.

Flow cytometry is a widely available technique for analyzing cell-surface protein expression. Data obtained from flow cytometry is frequently used to produce fluorescence intensity histograms. Comparison of histograms can be useful in the identification of unknown molecules and in the analysis of protein expression. In this study, we examined the combination of a new smoothing technique called SiZer with information theory to measure the difference between cytometry histograms. SiZer provides cross-bandwidth smoothing and allowed analysis in feature space. The new methods were tested on a panel of monoclonal antibodies raised against proteins expressed on peripheral blood lymphocytes and compared with previous methods. The findings suggest that comparing information content of histograms in feature space is effective and efficient for identifying antibodies with similar cell-surface binding patterns.

Animals↗

PubMed2002

[Leaf photosynthetic acclimation of Echinochloa crusgalli grown in rice field to free-air CO2 enrichment (FACE)].

A comparative study was made between the leaves of Echinochloa crusgalli grown at 580 (FACE) and 380 (control, ambient air) mumol CO2 mol-1 air by observation of net photosynthetic rates (Pn) and the contents of soluble protein and the key enzyme of photosynthetic carbon assimilation, Rubisco. When measured at the ambient air CO2 concentration (380 mumol.mol-1), Pn were significantly lower in leaves grown under FACE conditions than that in those leaves grown in the ambient air. This indicates that photosynthetic acclimation to high CO2 occurs in the leaves grown under FACE conditions. Also, the stomatal conductance (Gs) and intercellular CO2 concentration (Ci) were decreased significantly in the leaves grown under FACE. The content of total soluble protein was much lower in the leaves grown under FACE conditions than that the in the control, and the content of Rubisco was also decreased in the FACE leaves, but the difference was not significant. From these results it is deduced that the photosynthetic acclimation to high CO2 in Echinochloa crusgalli leaves grown under FACE conditions is mainly related to the partial closure of stomata and the decrease in soluble protein containing some enzymes.

Acclimatization↗

PubMed2002

[Responses of rice (Oryza sativa) growth and its C, N and P composition to FACE (free-air carbon dioxide enrichment) and N, P fertilization].

FACE (Free-air Carbon Dioxide Enrichment) was used to study the effects of elevated CO2 on rice (Oryza sativa) growth, tissue C/N, N and P concentration and uptake at different development stages under two N and two P levels. Results showed that elevated CO2 increased dry matter accumulation in rice stem, ear and root. Leaf dry matter was increased at tillering stage and no significant effect was found at jointing, heading and ripening stages. N concentration of stem and leaf was decreased. Ear N concentration at heading stage was increased but was decreased at ripening stage. No significant effect was found on root N concentration at tillering stage but root N concentration at jointing, heading and ripening was decreased. Leaf P concentration at jointing, heading and ripening was increased but no significant effect was found on P concentration in stem, ear and root. C content in various tissues changed unremarkably and the ratio of C over N (C/N) was increased. Elevated CO2 significantly increased P uptake in aboveground tissues; and increased N uptake, but the difference was not statistically significant. N and P fertilization had no significant effect on various tissue dry biomass. Tissue N content at higher N fertilization was higher than at lower N fertilization but no such effect of P fertilization on tissue P content was found. At higher N fertilization, elevated CO2 increased the ratio of below-ground biomass over above-ground biomass at ripening stage. Possible reasons are discussed for the differences of tissue N and P content and the ratio of below-ground biomass over above-ground biomass between elevated and ambient atmospheric CO2 concentrations.

Air↗

PubMed2002

[Effect of FACE on competition between a C3 crop (rice, Oryza sativa) and a C4 weed (barnyardgrass, Echinochloa crusgalli)].

The growth and competition of a C3 crop rice and a C4 weed, barnyardgrass under FACE(free-air carbon dioxide enrichment) conditions were studied by field experiment. The results showed that under FACE condition, the biomass and yield, leaf number, tiller number, and leaf area index of rice increased, while those of barnyardgrass decreased. Both of the leaf area indexed of rice and barnyardgrass were decreased, while their net assimilation rate increased. When the ratio of planting density of rice and barnyardgrass was 1:1, all of the ratio of biomass, yield, leaf area index, tiller and net assimilation rate were increased under FACE condition. It indicated that the competition between rice and barnyardgrass changed under FACE condition. The competition ability of rice(C3 crop) was enhanced relatively, while that of barnyardgrass weakened.

Carbon Dioxide↗

PubMed2002

[Elevated atmospheric CO2 and crop/weed competition].

Elevated atmospheric CO2 has direct photosynthesis effects on photosynthesis, respiration and water use efficiency, as well as on the growth and reproduction of plants. CO2 enrichment is more beneficial to plants with the C3 photosynthetic pathway than to those with the C4 photosynthetic pathway. Most major weeds are C4 plants, while many crops are C3 plant. Therefore, different effects of elevated atmospheric CO2 have important implications for weed/crop interaction. In this paper, the effect of CO2 enrichment and global chang on weed/crop interaction were summarized, and some theoretical and practical aspects were discussed.

Atmosphere↗

PubMedDate not supplied

Lack of toxicity of EGFR antisense gene therapy.

PURPOSE: EGFR is overexpressed in many human cancer cells, including head and neck squamous cell carcinoma (HNSCC). We have previously shown that elevated EGFR levels in the primary HNSCC tumor are associated with decreased survival. Reduction of EGFR tumor expression levels using an antisense EGFR sequence under the control of the U6 small nuclear RNA promoter abrogates tumor growth in a head and neck xenograft model. In support of a phase I clinical trial of an EGFR antisense gene-liposome complex administered to HNSCC patients, we conducted a series of studies to evaluate the safety of intralesional injections of EGFR liposomal antisense gene therapy in normal mice. METHODS: Three dose tiers were examined including the starting DNA-lipid dose for the clinical trial. RESULTS: Tissues and blood were harvested from mice treated with the liposome-mediated gene therapy and control mice at several time points for analysis. In this dosing range, administration of the antisense EGFR DNA-liposome complex had no apparent adverse effect on renal, hepatic and hematologic parameters studied. No major organ pathologic changes were observed. CONCLUSIONS: These results suggest that the toxicity of intralesional EGFR antisense DNA plus liposomes is restricted to a self-limited inflammation at the injection site, and may be well-tolerated in the clinical setting. EGFR antisense gene therapy was reviewed by the Recombinant DNA Advisory Committee and the Food and Drug Administration, and a phase I clinical trial is currently underway in patients with advanced HNSCC.

Animals↗

PubMedDate not supplied

Providing concept-oriented views for clinical data using a knowledge-based system: an evaluation.

OBJECTIVE: Clinical information systems typically present patient data in chronologic order, organized by the source of the information (e.g., laboratory, radiology). This study evaluates the functionality and utility of a knowledge-based system that generates concept-oriented views (organized around clinical concepts such as disease or organ system) of clinical data. DESIGN: The authors have developed a system that uses a knowledge base of interrelationships between medical concepts to infer relationships between data in electronic medical records. They use these inferences to produce summaries, or views, of the data that are relevant to a specific concept of interest. They evaluated the ability of the system to select relevant information, reduce information overload, and support physician information retrieval. MEASUREMENTS: The sensitivity and specificity of the system for identifying relevant patient information were calculated. Effect on information overload was assessed by comparing the amount of information in each view with the amount of information in the entire record. Information retrieval accuracy and cost (time) were used to measure the effect of using concept-oriented views on the efficiency and effectiveness of retrievals. RESULTS: The sensitivity and specificity of the system for identifying relevant clinical information were generally in the range of 70 to 80 percent. Concept-oriented views are effective in reducing the amount of information retrieved (over 80 percent reduction) and, compared with source-oriented views, are able to improve physician retrieval accuracy (p=0.04). CONCLUSION: Computer-generated, concept-oriented views can be used to reduce clinician information overload and improve the accuracy of clinical data retrieval.

Artificial Intelligence↗