Biomedical subjects

Heping Zhou

Publications and source records attributed to Heping Zhou.

7 recordsLinked to original sources

PubMed2007

Development and characterization of porous silver-incorporated hydroxyapatite ceramic for separation and elimination of microorganisms.

A novel filter material for separating and eliminating microorganisms in water and gas was fabricated by incorporating silver ions into porous hydroxyapatite (HA) ceramics prepared by a starch additive technique. The porous ceramics reveal a microstructure of both large and small pores. Microorganism separating and eliminating properties of the porous silver-incorporated HA ceramics (PHA-Ag) were investigated by bacterial and viral filtration tests. The PHA-Ag demonstrated excellent separating and antibacterial effects on Escherichia coli and the mechanisms were studied. Adsorption of bacterial cells to the HA and the barricading effect of small pores contribute to the separating property of PHA-Ag, while the Ag+ ions equip the ceramics with antibacterial property. Furthermore, the PHA-Ag exhibited an observable virus-eliminating property and its probable mechanism was also discussed.

Biocompatible Materials↗

PubMed2005

Optimized normalization for antibody microarrays and application to serum-protein profiling.

The measurements of coordinated patterns of protein abundance using antibody microarrays could be used to gain insight into disease biology and to probe the use of combinations of proteins for disease classification. The correct use and interpretation of antibody microarray data requires proper normalization of the data, which has not yet been systematically studied. Therefore we undertook a study to determine the optimal normalization of data from antibody microarray profiling of proteins in human serum specimens. Forty-three serum samples collected from patients with pancreatic cancer and from control subjects were probed in triplicate on microarrays containing 48 different antibodies, using a direct labeling, two-color comparative fluorescence detection format. Seven different normalization methods representing major classes of normalization for antibody microarray data were compared by their effects on reproducibility, accuracy, and trends in the data set. Normalization with ELISA-determined concentrations of IgM resulted in the most accurate, reproducible, and reliable data. The other normalization methods were deficient in at least one of the criteria. Multiparametric classification of the samples based on the combined measurement of seven of the proteins demonstrated the potential for increased classification accuracy compared with the use of individual measurements. This study establishes reliable normalization for antibody microarray data, criteria for assessing normalization performance, and the capability of antibody microarrays for serum-protein profiling and multiparametric sample classification.

Adenocarcinoma↗

PubMed2005

Differential expression of cytokines in the brain and serum during endotoxin tolerance.

Using short- and long-course lipopolysaccharide (LPS) treatment regimens to induce endotoxin tolerance in rats, we compared TNF-alpha, IL-1beta, and IL-6 expression in the brain and serum following a LPS challenge. Serum corticosterone was also examined to evaluate the function of the hypothalamic-pituitary-adrenal (HPA) axis. We found that, during endotoxin tolerance, LPS-induced cytokine expression still occurred in the brain even when cytokines in the periphery were no longer induced, and that this differential cytokine expression may be mediated by corticosterone, a stress hormone and an anti-inflammatory agent.

Animals↗

PubMed2004

Two-color, rolling-circle amplification on antibody microarrays for sensitive, multiplexed serum-protein measurements.

The ability to conveniently and rapidly profile a diverse set of proteins has valuable applications. In a step toward further enabling such a capability, we developed the use of rolling-circle amplification (RCA) to measure the relative levels of proteins from two serum samples, labeled with biotin and digoxigenin, respectively, that have been captured on antibody microarrays. Two-color RCA produced fluorescence up to 30-fold higher than direct-labeling and indirect-detection methods using antibody microarrays prepared on both polyacrylamide-based hydrogels and nitrocellulose. Replicate RCA measurements of multiple proteins from sets of 24 serum samples were highly reproducible and accurate. In addition, RCA enabled reproducible measurements of distinct expression profiles from lower-abundance proteins that were not measurable using the other detection methods. Two-color RCA on antibody microarrays should allow the convenient acquisition of expression profiles from a great diversity of proteins for a variety of applications.

Antibodies↗

PubMed2004

Multiplexed protein analysis using spotted antibody microarrays.

This chapter describes methods for the production and use of antibody microarrays. The methods are divided into (a) antibody handling and microarray production, (b) sample preparation, and (c) microarray use. Two types of detection methods are described: direct labeling and a fluorescence-linked immunosorbent assay (FLISA). In the direct labeling method, all proteins in a complex mixture are labeled with either a fluorophore or a hapten that allows subsequent detection. In FLISA detection, a capture antibody on the microarray captures the unlabeled protein target, which is detected by a detection antibody and a fluorophore-labeled secondary antibody. Each method has particular optimal uses, which are discussed in the text.

Antibodies↗

PubMed2003

Microarrays of tumor cell derived proteins uncover a distinct pattern of prostate cancer serum immunoreactivity.

The broad characterization of the immune responses elicited by tumors has valuable applications in diagnostics and basic research. We present here the use of microarrays of tumor-derived proteins to profile the antibody repertoire in the sera of prostate cancer patients and controls. Two-dimensional liquid chromatography was used to separate proteins from the prostate cancer cell line LNCaP into 1760 fractions. These fractions were spotted in microarrays on coated microscope slides, and the microarrays were incubated individually with serum samples from 25 men with prostate cancer and 25 male controls. The amount of immunoglobulin bound to each fraction by each serum sample was quantified. Statistical analysis revealed that 38 of the fractions had significantly higher levels of immunoglobulin binding in the prostate cancer samples compared to the controls. Two fractions showed higher binding in the control samples. The significantly higher immunoglobulin reactivity from the prostate cancer samples may reflect a strong immune response to the tumors in the prostate cancer patients. We used multivariate analysis to classify the samples as either prostate cancer or control. In a cross-validation study, recursive partitioning classified the samples with 84% accuracy. A decision tree with two levels of partitioning classified the samples with 98% accuracy. Additional studies will allow further characterization of tumor antigens in prostate cancer and their significance for diagnosis. These results suggest that microarrays of fractionated proteins could be a powerful tool for tumor antigen discovery and cancer diagnosis.

Antibodies, Neoplasm↗

PubMed2003

Antibody microarray profiling of human prostate cancer sera: antibody screening and identification of potential biomarkers.

We developed a practical strategy for serum protein profiling using antibody microarrays and applied the method to the identification of potential biomarkers in prostate cancer serum. Protein abundances from 33 prostate cancer and 20 control serum samples were compared to abundances from a common reference pool using a two-color fluorescence assay. Robotically spotted microarrays containing 184 unique antibodies were prepared on two different substrates: polyacrylamide based hydrogels on glass and poly-1-lysine coated glass with a photoreactive cross-linking layer. The hydrogel substrate yielded an average six-fold higher signal-to-noise ratio than the other substrate, and detection of protein binding was possible from a greater number of antibodies using the hydrogels. A statistical filter based on the correlation of data from "reverse-labeled" experiment sets accurately predicted the agreement between the microarray measurements and enzyme-linked immunosorbent assay measurements, showing that this parameter can serve to screen for antibodies that are functional on microarrays. Having defined a set of reliable microarray measurements, we identified five proteins (von Willebrand Factor, immunoglobulinM, Alpha1-antichymotrypsin, Villin and immunoglobulinG) that had significantly different levels between the prostate cancer samples and the controls. These developments enable the immediate use of high-density antibody and protein microarrays in biomarker discovery studies.

Antibodies, Neoplasm↗