Matthew J LeBaron

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Signal transducer and activator of transcription-5 (Stat5) mediates prolactin (PRL)-induced differentiation and growth of breast epithelial cells. We have recently identified active Stat5 as a tumor marker of favorable prognosis in human breast cancer, and determined that Stat5 activation is lost during metastatic progression. Here we provide novel evidence(More)
Milk production remains suppressed in mammals during late pregnancy despite high levels of lactogenic polypeptide hormones. At parturition, associated with a precipitous fall in circulating progesterone, rising glucocorticoid levels synergize with prolactin to initiate copious milk production. This synergy is mediated at least in part through the(More)
Weight of evidence (WoE) approaches are recommended for interpreting various toxicological data, but few systematic and transparent procedures exist. A hypothesis-based WoE framework was recently published focusing on the U.S. EPA's Tier 1 Endocrine Screening Battery (ESB) as an example. The framework recommends weighting each experimental endpoint(More)
Signal Transducer and Activator of Transcription 5 A and B (STAT5) are key survival factors in cells of the lymphoid lineage. Identification of novel, tissue-specific STAT5 regulated genes would advance the ability to combat diseases due to aberrant STAT5 signaling. In the present work a library of human STAT5 bound genomic elements was created and(More)
To identify cell populations directly responsive to prolactin (PRL), GH, erythropoietin, or granulocyte-colony stimulating factor within the physiological setting of an intact mammal, we combined in situ detection of hormone-activated signal transducer and activator of transcription (Stat)-5 in rats with high-throughput tissue array analysis using(More)
Identifying regulators of prostate cancer cell survival may lead to new therapeutic strategies for prostate cancer. We now report prevalent activation of transcription factor Stat5 in human prostate cancer and provide novel evidence that blocking activation of Stat5 in human prostate cancer cells leads to extensive cell death. Specifically, Stat5 was(More)
Registration of new plant protection products (e.g., herbicide, insecticide, or fungicide) requires comprehensive mammalian toxicity evaluation including carcinogenicity studies in two species. The outcome of the carcinogenicity testing has a significant bearing on the overall human health risk assessment of the substance and, consequently, approved uses(More)
We present a sectioning and bonding technology to make ultrahigh density microarrays of solid samples, cutting edge matrix assembly (CEMA). Maximized array density is achieved by a scaffold-free, self-supporting construction with rectangular array features that are incrementally scalable. This platform technology facilitates arrays of >10,000 tissue(More)
Epigenetics, as it pertains to biology and toxicology, can be defined as heritable changes in gene expression that do not involve mutations and are propagated without continued stimulus. Although potentially reversible, these heritable changes may be classified as mitotic, meiotic, or transgenerational, implicating the wide-ranging impact of epigenetic(More)
Tissue microarrays have become widely adopted for effective parallel in situ analysis of hundreds of tissues placed onto single slides. Traditionally, tissue core punches are transferred into predrilled holes within a scaffold block of paraffin or other material, and sectioned transversely by a microtome to generate array sections. While core-based arraying(More)