A retrospective observational cohort study of the anesthetic management and outcomes of pediatric patients with Alexander disease undergoing lumbar puncture or magnetic resonance imaging.

BACKGROUND: Alexander disease is a rare, progressive leukodystrophy, which predisposes patients to complications under general anesthesia due to clinical manifestations including developmental delay, seizures, dysphagia, vomiting, and sleep apnea. However, study of anesthetic outcomes is limited. AIMS: Our aim was to describe patient characteristics, anesthetic techniques, and anesthesia-related complications for Alexander disease patients undergoing magnetic resonance imaging and/or lumbar puncture at a quaternary-care children's hospital. METHODS: We performed a retrospective review of anesthetic outcomes in patients with Alexander disease enrolled in a prospective observational study. Included patients had diagnosed Alexander disease and underwent magnetic resonance imaging and/or lumbar puncture at our institution. We excluded anesthetics for other procedures or at outside institutions. Collected data included patient characteristics, anesthetic techniques, medications, and complications under anesthesia and in the subsequent 24 h. We performed descriptive statistics as appropriate. RESULTS: Forty patients undergoing 64 procedures met inclusion criteria. Fifty-six procedures (87.5%) required general anesthesia or monitored anesthesia care (MAC) and eight (12.5%) did not. The general anesthesia/MAC group tended to be younger than nonanesthetized patients (median age 6 years [IQR 3.8; 9] vs. 14.5 years [IQR 12.8; 17.5]). In both groups, dysphagia (78.6% vs. 87.5%, respectively), seizures (62.5% vs. 25%), and recurrent vomiting (17.9% vs. 25%) were frequently reported preprocedure symptoms. Inhalational induction was common (N = 48; 85.7%), and two (3.6%) underwent rapid sequence induction. Serious complications were rare, with no aspiration or seizures. Hypotension resolving with ephedrine occurred in eight cases (14.3%). One patient each (1.8%) experienced postprocedure emergence agitation or vomiting. Fifty-three (94.6%) were ambulatory procedures. No inpatients required escalation in acuity of care. CONCLUSIONS: In this single-center study, patients with Alexander disease did not experience frequent or irreversible complications while undergoing general anesthesia/MAC. Co-morbid symptoms were not increased postanesthesia. Some patients may not require anesthesia to complete short procedures.

AMXT-1501, a novel polyamine transport inhibitor, synergizes with DFMO in inhibiting neuroblastoma cell proliferation by targeting both ornithine decarboxylase and polyamine transport.

Neuroblastoma (NB) is associated with MYCN oncogene amplification occurring in approximately 30% of NBs and is associated with poor prognosis. MYCN is linked to a number of genes including ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis. ODC expression is elevated in many forms of cancer including NB. Alpha-difluoromethylornithine (DFMO), an ODC inhibitor, is currently being used in a Phase I clinical trial for treatment of NB. However, cancer cells treated with DFMO may overcome their polyamine depletion by the uptake of polyamines from extracellular sources. A novel polyamine transport inhibitor, AMXT-1501, has not yet been tested in NB. We propose that inhibiting ODC with DFMO, coupled with polyamine transport inhibition by AMXT-1501 will result in enhanced NB growth inhibition. Single and combination drug treatments were conducted on three NB cell lines. DFMO IC50 values ranged from 20.76 to 33.3 mM, and AMXT-1501 IC50 values ranged from 14.13 to 17.72 µM in NB. The combination treatment resulted in hypophosphorylation of retinoblastoma protein (Rb), suggesting growth inhibition via G1 cell cycle arrest. Increased expression of cleaved PARP and cleaved caspase 3 in combination-treated cells starting at 48 hr suggested apoptosis. The combination treatment depleted intracellular polyamine pools and decreased intracellular ATP, further verifying growth inhibition. Given the current lack of effective therapies for patients with relapsed/refractory NB and the preclinical effectiveness of DFMO with AMXT-1501, this combination treatment provides promising preclinical results. DFMO and AMXT-1501 may be a potential new therapy for children with NB.

Deletion of the SPARC acidic domain or EGF-like module reduces SPARC-induced migration and signaling through p38 MAPK/HSP27 in glioma.

We previously demonstrated that secreted protein acidic and rich in cysteine (SPARC) increases heat shock protein 27 (HSP27) expression and phosphorylation and promotes glioma cell migration through the p38 mitogen-activated protein kinase (MAPK)/HSP27 signaling pathway. As different regions of the SPARC protein mediate different SPARC functions, elucidating which SPARC domains regulate HSP27 expression, signaling and migration might provide potential therapeutic strategies to target these functions. To investigate the roles of specific domains, we used an SPARC-green fluorescent protein (GFP) fusion protein and constructs of SPARC-GFP with deletions of either the acidic domain (ΔAcidic) or the epidermal growth factor (EGF)-like module (ΔEGF). GFP, SPARC-GFP and the two deletion mutants were expressed in U87MG glioma cells. Characterization of the derived stable clones by confocal imaging and western blotting suggests proper folding, processing and secretion of the deletion constructs. Uptake of the constructs by naive cells suggests enhanced internalization of ΔAcidic and reduced internalization of ΔEGF. Wound and transwell migration assays and western blot analysis confirm our previous results and indicate that ΔAcidic reduces SPARC-induced migration and p38 MAPK/HSP27 signaling and ΔEGF decreases SPARC-induced migration and dramatically decreases the expression and phosphorylation of HSP27 but is poorly internalized. Loss of the EGF-like module suppresses the enhanced HSP27 protein stability conferred by SPARC. In conclusion, deletions of the acidic domain and EGF-like module have differential effects on cell surface binding and HSP27 protein stability; however, both regions regulate SPARC-induced migration and signaling through HSP27. Our data link the domains of SPARC with different functions and suggest one or both of the constructs as potential therapeutic agents to inhibit SPARC-induced migration.

Anesthetic management of tracheoesophageal fistula repair in a newborn with a double-outlet right ventricle.

A case of a newborn with a double-outlet right ventricle and tracheoesophageal fistula is presented. The pathophysiology of double-outlet right ventricle and its anesthetic implications for tracheoesophageal fistula repair are discussed.

Bradycardia during induction of anesthesia with sevoflurane in children with Down syndrome.

BACKGROUND: Bradycardia is a complication associated with inhaled induction of anesthesia with halothane in children with Down syndrome. Although bradycardia has been reported after anesthetic induction with sevoflurane in these children, the incidence is unknown. OBJECTIVES: In this study we compared the incidence and characteristics of bradycardia after induction of anesthesia with sevoflurane in children with Down syndrome to healthy controls. METHODS: We reviewed electronic anesthetic records of 209 children with Down syndrome and 268 healthy control patients who had inhaled induction of anesthesia with sevoflurane over an 8-year period. Data extracted from the medical record included demographics, history of congenital heart disease, heart rate, oxyhemoglobin saturation, expired sevoflurane concentrations, arterial blood pressure, and any treatment of bradycardia during the first 360 seconds after the start of induction of anesthesia. Bradycardia and hypotension were defined as heart rate and arterial blood pressure below the critical limits recommended for activating a pediatric rapid response team to the bedside of a hospitalized child for quick intervention. Factors associated with bradycardia were identified in a univariate analysis. A step-wise backward multiple logistic regression model was used to identify independent factors. Differences between the 2 groups were computed using Fisher's exact test or χ(2) tests for categorical data and t tests for continuous data. RESULTS: Univariate analysis demonstrated that Down syndrome, low ASA physical status, congenital heart disease, and mean sevoflurane concentrations were factors associated with bradycardia. However, multivariate analysis showed that only Down syndrome and low ASA physical status remained as independent factors associated with bradycardia. CONCLUSION: Bradycardia during anesthetic induction with sevoflurane was common in children with Down syndrome, with and without a history of congenital heart disease.

HSP27 mediates SPARC-induced changes in glioma morphology, migration, and invasion.

Secreted protein acidic and rich in cysteine (SPARC) regulates cell-extracellular matrix interactions that influence cell adhesion and migration. We have demonstrated that SPARC is highly expressed in human gliomas, and it promotes brain tumor invasion in vitro and in vivo. To further our understanding regarding SPARC function in glioma migration, we transfected SPARC-green fluorescent protein (GFP) and control GFP vectors into U87MG cells, and assessed the effects of SPARC on cell morphology, migration, and invasion after 24 h. The expression of SPARC was associated with elongated cell morphology, and increased migration and invasion. The effects of SPARC on downstream signaling were assessed from 0 to 6 h and 24 h. SPARC increased the levels of total and phosphorylated HSP27; the latter was preceded by activation of p38 MAPK and inhibited by the p38 MAPK inhibitor SB203580. Augmented expression of SPARC was correlated with increased levels of HSP27 mRNA. In a panel of glioma cell lines, increasing levels of SPARC correlated with increasing total and phosphorylated HSP27. SPARC and HSP27 were colocalized to invading cells in vivo. Inhibition of HSP27 mRNA reversed the SPARC-induced changes in cell morphology, migration, and invasion in vitro. These data indicate that HSP27, a protein that regulates actin polymerization, cell contraction, and migration, is a novel downstream effector of SPARC-regulated cell morphology and migration. As such, it is a potential therapeutic target to inhibit SPARC-induced glioma invasion.

SPARC upregulates MT1-MMP expression, MMP-2 activation, and the secretion and cleavage of galectin-3 in U87MG glioma cells.

Secreted protein acidic and rich in cysteine (SPARC) is highly expressed in human gliomas and promotes glioma invasion. We have shown by cDNA array analysis that SPARC upregulates membrane type 1-matrix metalloproteinase (MT1-MMP) and matrix metalloproteinase-2 (MMP-2) transcripts. To confirm these findings at the protein level and determine whether SPARC expression correlates with increased MMP activity, we used Western blot to assess the levels of MT1-MMP, and gelatin zymography to assess MMP-2 levels and activity. We also examined the expression, secretion, and cleavage of galectin-3, a target of MT1-MMP and MMP-2. Our data confirm that SPARC upregulates MT1-MMP levels and MMP-2 activity. There was also an increase in secreted galectin-3, as well as an increase in the proteolytically processed form of galectin-3. Previous studies have demonstrated that MT1-MMP, MMP-2, and galectin-3 are increased in gliomas. Our results suggest that their upregulation and activation may be a consequence of increased SPARC expression. These data provide a provisional mechanism whereby SPARC contributes to brain tumor invasion.