Plasma MicroRNAs as sensitive and specific biomarkers of tissue injury.

Background: MicroRNAs (miRNAs) are endogenous, small noncoding RNAs. Because of their size, abundance, tissue specificity, and relative stability in plasma, miRNAs hold promise as unique accessible biomarkers to monitor tissue injury.

Methods: We investigated the use of liver-, muscle- and brain-specific miRNAs as circulating biomarkers of tissue injury.

Improved high-throughput ultrafiltration process enables cRNA purification for gene expression profiling.

Ultrafiltration of nucleic acids has been used for a wide variety of applications, including sequence reaction purification and amplicon cleanup prior to spotting onto microarrays. Here we describe a novel process, using ultrafiltration, that purifies cRNA products for sensitive downstream applications. Initial attempts at this high-throughput purification for cRNA resulted in low sensitivity when compared against an industry standard (silica-based bind, wash, and elute purification).

Reagent preparation and storage for amplification of microarray hybridization targets with a fully automated system.

The advent of automated systems for gene expression profiling has accentuated the need for the development of convenient and cost-effective methods for reagent preparation. We have developed a method for the preparation and storage of pre-aliquoted cocktail plates that contain all reagents required for amplification of nucleic acid by reverse transcription and in vitro transcription reactions. Plates can be stored at -80 degrees C for at least 1 month and kept in a hotel at 4 degrees C for at least 24 h prior to use.

A microarray platform comparison for neuroscience applications.

To address the need for high sensitivity in gene expression profiling of small neural tissue samples ( approximately 100 ng total RNA), we compared a novel RT-PCR-IVT protocol using fluor-reverse pairs on inkjet oligonucleotide microarrays and an RT-IVT protocol using 33P labeling on nylon cDNA arrays. The comparison protocol was designed to evaluate these systems for sensitivity, specificity, reproducibility, and linearity. We developed parameters, thresholds, and testing conditions that could be used to differentiate various systems that spanned detection chemistry and instrumentation; probe number and selection criteria; and sample processing protocols.

Effects of atmospheric ozone on microarray data quality.

A data anomaly was observed that affected the uniformity and reproducibility of fluorescent signal across DNA microarrays. Results from experimental sets designed to identify potential causes (from microarray production to array scanning) indicated that the anomaly was linked to a batch process; further work allowed us to localize the effect to the posthybridization array stringency washes. Ozone levels were monitored and highly correlated with the batch effect.