Thermal defense of extremely low gestational age newborns during resuscitation: exothermic mattresses vs polyethylene wrap.

OBJECTIVE: The purpose of this study was to assess the effectiveness of thermal warming mattresses compared with wrapping in a polyethylene sheet during resuscitation in extremely low gestational age newborns (ELGANs) in preventing admission hypothermia in the neonatal intensive care unit. STUDY DESIGN: Patients delivered between 24 and 28 weeks gestation and ≤1250 g were eligible for this prospective, randomized study. In the delivery room, the resuscitation team opened a sealed opaque envelope for treatment group assignment to either the wrap or the sodium acetate mattress group. Resuscitation followed protocols recommended by the Neonatal Resuscitation Program. The primary outcome for this study was comparison of axillary temperatures recorded at the time of neonatal intensive care unit admission between the two groups. RESULT: Thirty-nine patients were enrolled in the study. The mattress group's mean admission temperature was 36.5±0.67, whereas the plastic wrap group's was 36.1±0.66 (P=0.0445). CONCLUSION: Thermal mattresses improved admission temperature for ELGANs over plastic wrap. Although both plastic wrap and thermal mattresses improve the thermal status of ELGANs, all current interventions fall short of truly protecting all these vulnerable patients from thermal stress.

Ablation of Stat3 by siRNA alters gene expression profiles in JEG-3 cells: a systems biology approach.

Control of inflammation at the maternal-fetal interface is a critical element in mammalian pregnancy. Previous work from our laboratory has shown that Stat3 may be a placental mediator involved in maintaining immunologic homeostasis at the maternal-fetal interface. The aim of the current study is to further elucidate the role of Stat3 in response to inflammation. As ablation of Stat3 in mice results in embryonic lethality, we evaluated the role of Stat3 in vitro using an siRNA approach. Trophoblast-like JEG-3 cells were transfected with an siRNA construct specific to Stat3. Experimental and control cells were exposed to conditioned medium from PHA-activated peripheral blood mononuclear cells and incubated for 45 min. Cells were then collected and RNA isolated for transcriptional profiling using human Affymetrix U133 plus 2.0 GeneChips. Differences in gene expression between control and Stat3-ablated cells were evaluated using conventional statistical methods. Fifty-two genes were detected as up-regulated in conditioned medium in both mock transfected and in Stat3 siRNA transfected JEG-3 cells. Two genes (EPAS1 and RASGEF1B) were up-regulated only in cells transfected with negative control siRNA, while 36 genes were up-regulated only in cells transfected with Stat3 siRNA. Sixty genes were differentially expressed between Stat3 siRNA transfected cells relative to mock transfected cells both in basal and conditioned medium. These included 31 genes up-regulated with Stat3 siRNA transfected cells and 29 genes down-regulated with Stat3 siRNA. Eleven genes were differentially expressed only in basal medium. Seven of these were up-regulated in the presence of Stat3 siRNA and four were down-regulated. Nine genes were differentially expressed only in conditioned medium. Six of these were up-regulated and three down-regulated in the presence of Stat3 siRNA. Off-target effects were excluded in a second set of experiments in which Stat3 mRNA was targeted at a different site and quantitative real-time PCR performed on selected genes derived from the microarray analysis. While some of the genes that showed differential expression between Stat3-ablated cells and mock transfected controls were genes typically associated with immune response (e.g., CCR7 and IRAK1), in silico modeling of the microarray data also revealed complex networks of signaling molecules and molecules associated with cellular metabolism previously seen in transcription factor ablation in model organisms. We conclude thus: Stat3 controls a specific gene set in trophoblast-like JEG-3 cells. While some differentially expressed genes and in silico models of their functions are consistent with the hypothesis that Stat3 plays a role in regulating inflammation, Stat3-mediated response to inflammation appears to also involve complex homeostatic adaptations of a non-immunologic nature.