Biomedical subjects

Benjamin S Wallis

Publications and source records attributed to Benjamin S Wallis.

4 recordsLinked to original sources

PubMed2006

Tumor-associated endothelial cells display GSTP1 and RARbeta2 promoter methylation in human prostate cancer.

BACKGROUND: A functional blood supply is essential for tumor growth and proliferation. However, the mechanism of blood vessel recruitment to the tumor is still poorly understood. Ideally, a thorough molecular assessment of blood vessel cells would be critical in our comprehension of this process. Yet, to date, there is little known about the molecular makeup of the endothelial cells of tumor-associated blood vessels, due in part to the difficulty of isolating a pure population of endothelial cells from the heterogeneous tissue environment. METHODS: Here we describe the use of a recently developed technique, Expression Microdissection, to isolate endothelial cells from the tumor microenvironment. The methylation status of the dissected samples was evaluated for GSTP1 and RARbeta2 promoters via the QMS-PCR method. RESULTS: Comparing GSTP1 and RARbeta2 promoter methylation data, we show that 100% and 88% methylation is detected, respectively, in the tumor areas, both in epithelium and endothelium. Little to no methylation is observed in non-tumor tissue areas. CONCLUSION: We applied an accurate microdissection technique to isolate endothelial cells from tissues, enabling DNA analysis such as promoter methylation status. The observations suggest that epigenetic alterations may play a role in determining the phenotype of tumor-associated vasculature.

Journal Article↗

PubMed2005

Layered peptide arrays: high-throughput antibody screening of clinical samples.

High-throughput methods to detect and quantify antibodies in sera and other patient specimens have use for many clinical and laboratory studies, including those associated with cancer detection, microbial exposures, and autoimmune diseases. We developed a new technique, termed layered peptide array (LPA), to serve as a screening tool to detect antibodies in a highly multiplexed format. We demonstrate here that a prototype LPA was capable of producing approximately 5000 measurements per experiment and appeared to be scalable to higher throughput levels. Sera and saliva from Sjögren's syndrome patients served as a test set to examine antibody titers in clinical samples. The LPA platform exhibited both a high sensitivity (100%) and high specificity (94%) for correctly identifying SSB antigen-positive samples. The multiplex capability of the platform was also confirmed when serum and saliva samples were analyzed for antibody reactivity to several peptides, including Sjögren's syndrome antigens A and B. The data indicate that LPA analysis will be a useful method for a number of screening applications.

Antibodies↗

PubMed2004

Expression microdissection: operator-independent retrieval of cells for molecular profiling.

Tissue microdissection is an important method for the study of disease states. However, it is difficult to perform high-throughput molecular analysis with current techniques. We describe here a prototype version of a novel technique (expression microdissection) that allows for the procurement of desired cells via molecular targeting. Expression microdissection (xMD) offers significant advantages over available methods, including an increase in dissection speed of several orders of magnitude. xMD may become a valuable tool for investigators studying cancer or other disease states in patient specimens and animal models.

Animals↗

PubMed2004

Novel proteomic approaches for tissue analysis.

Proteomics, the global study of protein expression and characteristics, has recently emerged as a key component in the field of molecular analysis. The dynamic nature of proteins, from ion channels to chaperones, presents a challenge, yet the understanding of these molecules provides a rich source of information. When applying proteomic analysis directly to human tissue samples, additional difficulties arise. The following article presents an overview of the current proteomic tools used in the analysis of tissues, beginning with conventional methods such as western blot analysis and 2D polyacrylamide gel electrophoresis. The most current high-throughput techniques being used today are also reviewed. These include protein arrays, reverse-phase protein lysate arrays, matrix-assisted laser desorption/ionization, surface-enhanced laser desorption/ionization and layered expression scanning. In addition, bioinformatics as well as issues regarding tissue preservation and microdissection to obtain pure cell populations are included. Finally, future directions of the tissue proteomics field are discussed.

Animals↗