Search

Antimuscarinic toxicity can result in temperature dysregulation, but the clinical significance of this is unclear. The objective of this study was to compare peak temperatures between antimuscarinic patients with and without severe clinical outcomes.This was a case-control analysis at two large, urban, academic medical centers from January 1, 2016, through December 31, 2021. We compared peak temperature (Fifty-six patients met inclusion criteria of which 23 developed severe outcomes: 16 seizures, 9 cases with hypotension, 5 intubations, and 2 ventricular dysrhythmias. Tmax amongst all patients ranged from 36.4-39.2 °C. There were no fatalities. There was no difference in Tmax in the emergency department or throughout hospitalization between groups, and Tmax was not predictive for the development of severe outcomes.Maximum temperatures did not differ between patients with and without severe outcomes in the setting of antimuscarinic toxicity, and temperature was poorly predictive of outcomes. Our findings suggest that mild temperature dysregulation in antimuscarinic toxicity is not a key prognostic indicator for severe outcome. Further study is needed to assess implication of severe hyperthermia.

INTRODUCTION: Valproic acid (VPA) toxicity commonly results in a self-limited state of CNS depression that is managed with supportive care and levocarnitine. In massive overdose, patients can develop toxic encephalopathy, shock, multisystem organ failure, and death. We present a case with relevant toxicokinetics of a patient presenting with a profoundly elevated VPA concentration resulting in survival, treated with supportive care including high-dose continuous venovenous hemodiafiltration (CVVHDF). CASE REPORT: A 17-year-old female presented to an emergency department after being found unresponsive at home with concern for massive VPA ingestion. She arrived obtunded and hypotensive with initial VPA concentration of 2226 mg/L, estimated 9 h post-ingestion. Her early hospital course was marked by hypotension requiring multiple vasopressors, and her workup was notable for multiple severe metabolic derangements. High-dose CVVHDF was initiated upon transfer to a tertiary children’s hospital with the aim to enhance VPA removal and normalize metabolic derangements. At that time, her VPA concentration was 1071 mg/L. Apparent half-life of VPA improved modestly with extracorporeal treatment, but her metabolic derangements and hemodynamic instability corrected rapidly. Her clinical course was complicated by necrotizing pancreatitis, pancytopenia requiring transfusions of multiple cell lines, coma, and seizures. She ultimately recovered with normal neurological function.

SummaryThe evolutionarily ancient arm of the E2f family of transcription factors consisting of the two atypical members E2f7 and E2f8 is essential for murine embryonic development. However, the critical tissues, cellular processes, and molecular pathways regulated by these two factors remain unknown. Using a series of fetal and placental lineage-specific cre mice, we show that E2F7/E2F8 functions in extraembryonic trophoblast lineages are both necessary and sufficient to carry fetuses to term. Expression profiling and biochemical approaches exposed the canonical E2F3a activator as a key family member that antagonizes E2F7/E2F8 functions. Remarkably, the concomitant loss of E2f3a normalized placental gene expression programs, corrected placental defects, and fostered the survival of E2f7/E2f8-deficient embryos to birth. In summary, we identified a placental transcriptional network tightly coordinated by activation and repression through two distinct arms of the E2F family that is essential for extraembryonic cell proliferation, placental development, and fetal viability.

SUMMARY The endocycle is a variant cell cycle consisting of successive DNA synthesis and Gap phases that yield highly polyploid cells. Although essential for metazoan development, relatively little is known about its control or physiologic role in mammals. Using novel lineage-specific cre mice we identified two opposing arms of the E2F program, one driven by canonical transcription activation (E2F1, E2F2 and E2F3) and the other by atypical repression (E2F7 and E2F8), that converge on the regulation of endocycles in vivo. Ablation of canonical activators in the two endocycling tissues of mammals, trophoblast giant cells in the placenta and hepatocytes in the liver, augmented genome ploidy, whereas ablation of atypical repressors diminished ploidy. These two antagonistic arms coordinate the expression of a unique G2/M transcriptional program that is critical for mitosis, karyokinesis and cytokinesis. These results provide in vivo evidence for a direct role of E2F family members in regulating non-traditional cell cycles in mammals.

The E2f7 and E2f8 family members are thought to function as transcriptional repressors important for the control of cell proliferation. Here, we have analyzed the consequences of inactivating E2f7 and E2f8 in mice and show that their individual loss had no significant effect on development. Their combined ablation, however, resulted in massive apoptosis and dilation of blood vessels, culminating in lethality by embryonic day E11.5. A deficiency in E2f7 and E2f8 led to an increase in E2f1 and p53, as well as in many stress-related genes. Homo- and heterodimers of E2F7 and E2F8 were found on target promoters, including E2f1. Importantly, loss of either E2f1 or p53 suppressed the massive apoptosis in double-mutant embryos. These results identify E2F7 and E2F8 as a unique repressive arm of the E2F transcriptional network that is critical for embryonic development and control of the E2F1-p53 apoptotic axis.