Papers by Stephanie Brunelle
Clinical Cancer Research, 2004
Purpose: The purpose of this study was to assess the feasibility of using rare event imaging syst... more Purpose: The purpose of this study was to assess the feasibility of using rare event imaging system (REIS)assisted analysis to detect occult tumor cells (OTCs) in peripheral blood (PB). The study also sought to determine whether REIS-assisted OTC detection presents a clinically viable alternative to manual microscopic detection to establish the true significance of OTC from solid epithelial tumors. Experimental Design: We recently demonstrated proof of concept using a fluorescence-based automated microscope system, REIS, for OTC detection from the PB. For this study, the prototype of the system was adopted for highthroughput and high-content cellular analysis. Results: The performance of the improved REIS was examined using normal blood (n ؍ 10), normal blood added to cancer cells (n ؍ 20), and blood samples obtained from cancer patients (n ؍ 80). Data from the screening of 80 clinical slides from breast and lung cancer patients, by manual microscopy and by the REIS, revealed that as many as 14 of 35 positive slides (40%) were missed by manual screening but positively identified by REIS. In addition, REIS-assisted scanning reliably and reproducibly quantified the total number of cells analyzed in the assay and categorized positive cells based on their marker expression profile. Conclusions: REIS-assisted analysis provides excellent sensitivity and reproducibility for OTC detection. This approach may enable an improved method for screening of PB samples and for obtaining novel information about disease staging and about risk evaluation in cancer patients.
Journal of Eukaryotic Microbiology, 2011
Karenia brevis is a toxic dinoflagellate responsible for red tides in the Gulf of Mexico. The mol... more Karenia brevis is a toxic dinoflagellate responsible for red tides in the Gulf of Mexico. The molecular mechanisms controlling its cell cycle are important to bloom formation because blooms develop through vegetative cell division. This study identifies a suite of conserved S-phase genes in K. brevis-proliferating cell nuclear antigen (PCNA), ribonucleotide reductase 2, replication factor C, and replication protein A-and characterizes their expression at the mRNA and protein level over the cell cycle. In higher eukaryotes, the expression of these genes is controlled by transcription, activated at S-phase entry by the E2F transcription factor, which ensures their timely availability for DNA synthesis. In the dinoflagellate, these transcripts possess a 5'-transspliced leader sequence, which suggests they may be under post-transcriptional control as demonstrated in trypanosomes. Using quantitative polymerase chain reaction (qPCR), we confirmed that their transcript levels are unchanged over the cell cycle. However, their proteins are maximally expressed during S-phase. This suggests their cell-cycle-dependent expression may be achieved at the level of translation and/or stability. Proliferating cell nuclear antigen further undergoes an increase in size of ∼9 kDa that dominates during S-phase. This coincides with a change in its distribution, with prominent staining of chromatin-bound PCNA occurring during S-phase. We hypothesize that the change in the observed size of PCNA is due to post-translational modification. Together, these studies demonstrate post-transcriptional regulation of S-phase genes in K. brevis. Differential expression of these S-phase proteins may be useful in the development of biomarkers to assess bloom growth status in the field.
Journal of Phycology, 2007
The photoperiod plays a central role in regulating the physiology and behavior of photosynthetic ... more The photoperiod plays a central role in regulating the physiology and behavior of photosynthetic phytoplankton, and many of these processes are controlled by an underlying circadian rhythm. In dinoflagellates, circadian rhythms have been shown to depend largely on posttranscriptional regulation. However, the extent to which dinoflagellates modulate transcript levels to regulate gene expression in response to light and dark has not been addressed.
Journal of Phycology, 2007
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Papers by Stephanie Brunelle