DETECTION OF β-HUMAN CHORIONIC GONADOTROPIN EXPRESSING CELLS BY NESTED REVERSE TRANSCRIPTASE-POLYMERASE CHAIN REACTION IN THE PERIPHERAL BLOOD STEM CELLS OF PATIENTS WITH ADVANCED GERM CELL TUMOR

Directly functionalizable surface platform for protein arrays in undiluted human blood plasma

Protein arrays are a high-throughput approach for proteomic profiling, vital for achieving a greater understanding of biological systems, in addition to disease diagnostics and monitoring therapeutic treatments. In this work, zwitterionic carboxybetaine polymer (pCB) coated substrates were investigated as an array surface platform to enable convenient amino-coupling chemistry on a single directly functionalizable and unblocked film for the sensitive detection of target analytes from undiluted human blood plasma. Using a surface plasmon resonance (SPR) imaging sensor, the antibody immobilization conditions which provided excellent spot morphology and the largest antigen response were determined. It was found that pCB functionalization and the corresponding antigen detection both increased with pH and antibody concentration. Additionally, immobilization only required an aqueous buffer without the need for additives to improve spot quality. The nonspecific protein adsorption to undiluted human plasma on both the antibody immobilized pCB spots and the background were found to be about 9 and 6 ng/cm(2), respectively. A subsequent array consisting of three antibodies spotted onto pCB revealed little cross-reactivity for antigens spiked into the undiluted plasma. The low postfunctionalized nonfouling properties combined with antibody amplification showed similar sensitivities achievable with conventional spectroscopic SPR sensors and the same pCB films, but now with high-throughput capabilities. This represents the first demonstration of low fouling properties following antibody functionalization on protein arrays from undiluted human plasma and indicates the great potential of the pCB platform for high-throughput protein analysis.

Colon cancer: prevalence, screening, gene expression and mutation, and risk factors and assessment

Colon cancer detection at an early stage and identifying susceptible individuals can result in reduced mortality from this prevalent cancer. Genetic events leading to the development of this cancer involve a multistage progression of adenoma polyps to invasive metastatic carcinomas. Currently, there is no satisfactory screening method that is highly specific, sensitive, or reliable. Dietary patterns associated with the greatest increase in colon cancer risk are the ones that typify a diet rich in fat and calories, and low in vegetable, fruits, and fibers. Genetic susceptibility to environmental carcinogenesis must be factored into the risk assessment for this cancer. Many genes have been shown to be associated with increased expression and mutations in colorectal cancer patients. These genes have been reviewed; it is hoped that by carefully selecting a number of them, a molecular approach that is suitable for arriving at a tumorigenic expression index is developed, which will reliably detect this cancer at an early stage (i.e., before it metastasizes), especially in exfoliated samples (e.g., stool and blood), so that appropriate intervention strategies can be implemented. Illustrated herein is the utility of employing real-time reverse transcriptase polymerase chain reaction (RT-PCR) to quantitatively measure gene expression, and develop an index that is specific for this cancer, which if perfected may result in a reliable and sensitive screening technique for colorectal cancer detection.