Risk factors for apnea in children presenting with out-of-hospital seizure.

OBJECTIVE: This study aimed to quantify risk factors for apnea in children 0 to 5 years of age with out-of-hospital seizure. METHODS: This is a retrospective study of pediatric patients with seizure transported by paramedics to the pediatric emergency department (PED) of a tertiary center from July 2008 to June 2009. Patients with traumatic injury and those with another diagnosis after PED evaluation were excluded. We evaluated the effect of field diazepam and other potential risk factors on the occurrence of apnea, defined as the need for airway management, that is, bag-mask ventilation by paramedics or bag-mask ventilation or intubation by PED staff within 30 minutes of arrival. RESULTS: There were 336 pediatric patients meeting inclusion criteria. The median age was 1.9 years (interquartile range,1.3-3.0 years); 193 patients (57%) were male. Fifty-four patients (16%) were treated with diazepam before PED arrival. There were 28 apneic events (8.3%). The adjusted relative risk for apnea given diazepam in the field by any route was 10.2 (95% confidence interval, 3.9-21.8; P < 0.0001), adjusted for age and seizure on arrival. Persistent seizure on PED arrival was also highly associated with apnea, with an adjusted relative risk of 15.8 (95% confidence interval, 6.5-28.9; P < 0.0001). CONCLUSIONS: Field treatment with diazepam and seizing at the time of PED arrival are associated with the occurrence of apnea in children 0 to 5 years of age with out-of-hospital seizure. Larger studies are needed to determine what other factors may contribute to this risk.

Ethnic and racial differences in prostate stromal estrogen receptor alpha.

BACKGROUND: Prostate cancer incidence and mortality rates vary widely among individuals of different ethnic/racial groups. We identified a relationship between a subset of genes and race/ethnicity using gene expression profiling. Estrogen receptor alpha (ERalpha) was selected for confirmation due to its plausible biological role in cancer susceptibility. METHODS: Quantitative polymerase chain reaction (Q-PCR) was used to verify gene expression results. Protein levels of ERalpha were determined by quantitative immunohistochemistry in a large-scale tissue microarray study (n = 183). RESULTS: ERalpha was significantly higher in stroma of Hispanic and Asian men than in Caucasian (P < 0.0001) and African American men (P < 0.0002), who are at higher risk for prostate cancer. In addition, large differences were seen in Q-PCR levels of ERalpha in prostate tissues of organ donors 16-29 years old who had no evidence of cancer. CONCLUSIONS: ERalpha exhibits variable expression in men of difference racial/ethnic background. Understanding the molecular basis for these differences may form the basis for prostate cancer prevention strategies with widespread public health impact.

The gene expression signatures of melanoma progression.

Because of the paucity of available tissue, little information has previously been available regarding the gene expression profiles of primary melanomas. To understand the molecular basis of melanoma progression, we compared the gene expression profiles of a series of nevi, primary melanomas, and melanoma metastases. We found that metastatic melanomas exhibit two dichotomous patterns of gene expression, which unexpectedly reflect gene expression differences already apparent in comparing laser-capture microdissected radial and vertical phases of a large primary melanoma. Unsupervised hierarchical clustering accurately separated nevi and primary melanomas. Multiclass significance analysis of microarrays comparing normal skin, nevi, primary melanomas, and the two types of metastatic melanoma identified 2,602 transcripts that significantly correlated with sample class. These results suggest that melanoma pathogenesis can be understood as a series of distinct molecular events. The gene expression signatures identified here provide the basis for developing new diagnostics and targeting therapies for patients with malignant melanoma.

Chromatin immunoprecipitation (ChIP) scanning identifies primary glucocorticoid receptor target genes.

The global physiological effects of glucocorticoids are well established, and the framework of transcriptional regulation by the glucocorticoid receptor (GR) has been described. However, the genes directly under GR control that trigger these physiological effects are largely unknown. To address this issue in a single cell type, we identified glucocorticoid-responsive genes in A549 human lung adenocarcinoma cells by microarray analysis and quantitative real-time PCR. Reduction of GR expression by RNA interference diminished the effects of dexamethasone on all tested target genes, thus confirming the essential role of GR in glucocorticoid-regulated gene expression. To identify primary GR target genes, in which GR is a component of the transcriptional regulatory complex, we developed a strategy that uses chromatin immunoprecipitation to scan putative regulatory regions of target genes for sites occupied by specifically bound GR. We screened 11 glucocorticoid-regulated genes, and we identified GR-binding regions for eight of them (five induced and three repressed). Thus, our approach provides a means for rapid identification of primary GR target genes and glucocorticoid-response elements, which will facilitate analyses of transcriptional regulatory mechanisms and determination of hormone-regulated gene networks.

Target-specific utilization of transcriptional regulatory surfaces by the glucocorticoid receptor.

The glucocorticoid receptor (GR) activates or represses transcription depending on the sequence and architecture of the glucocorticoid response elements in target genes and the availability and activity of interacting cofactors. Numerous GR cofactors have been identified, but they alone are insufficient to dictate the specificity of GR action. Furthermore, the role of different functional surfaces on the receptor itself in regulating its targets is unclear, due in part to the paucity of known target genes. Using DNA microarrays and real-time quantitative PCR, we identified genes transcriptionally activated by GR, in a translation-independent manner, in two human cell lines. We then assessed in U2OS osteosarcoma cells the consequences of individually disrupting three GR domains, the N-terminal activation function (AF) 1, the C-terminal AF2, or the dimer interface, on activation of these genes. We found that GR targets differed in their requirements for AF1 or AF2, and that the dimer interface was dispensable for activation of some genes in each class. Thus, in a single cell type, different GR surfaces were used in a gene-specific manner. These findings have strong implications for the nature of gene response element signaling, the composition and structure of regulatory complexes, and the mechanisms of context-specific transcriptional regulation.

The transcriptome of the leukemogenic homeoprotein HOXA9 in human hematopoietic cells.

Hematopoietic defects in HOXA9(-/-) mice demonstrate a key role for this homeoprotein in blood cell development. Conversely, enforced HOXA9 expression is leukemogenic in mice, and HOXA9 is frequently activated in human acute myeloid leukemia (AML). Although HOXA9 is thought to function as a transcription factor, few downstream targets have been identified. We searched for early HOXA9 target genes by using a transient overexpression strategy in 3 hematopoietic cell lines (2 myeloid, 1 lymphoid). cDNA microarray analyses identified 220 genes whose expression was modulated at least 2-fold. Expression signatures in myeloid and lymphoid cells demonstrated that HOXA9 functions as both an activator and repressor of a variety of genes in cell-specific patterns suggesting that the transcriptional effects of HOXA9 are largely dependent on the cell context. Transient transcription assays and target gene expression patterns in HOXA9(-/-) marrow cells imply that we have identified direct physiologic targets. Many target genes are expressed in CD34+ stem cells or are members of gene families involved in proliferation or myeloid differentiation. Expression of 14 HOXA9 target genes correlated with high-level HOXA9 expression in primary AML. These data suggest that many genes identified in this survey may mediate the biologic effects of HOXA9 in normal and leukemic hematopoiesis.