Randomized trial of a self-administered parenting intervention for selective eating in young children.

Selective eating is a common childhood feeding problem associated with family stress and micronutrient deficiencies. While there are empirically-supported behavioral strategies for addressing selective eating, there are significant systems-level barriers to implementing them. The aim of this study was to develop and test a self-administered intervention for parents of children with selective eating. Participants were 156 parents of children with selective eating ages 18 months-6 years who were randomly assigned to either the handout + video condition (8-module video intervention and detailed handout) or handout condition (detailed handout only). Outcome measures were administered pre-intervention and 4 weeks post-intervention. Only 23 % of participants in the handouts plus video condition played more than one video module. Both groups had significant decreases in maladaptive mealtime parenting practices, undesired child mealtime behaviors, and number of foods offered. No significant effect of study condition was found on the outcome measures. Further research is needed to determine how to encourage engagement of parents with self-administered intervention materials.

Substituted Cysteine Modification and Protection with n-Alkyl- Methanethiosulfonate Reagents Yields a Precise Estimate of the Distance between Etomidate and a Residue in Activated GABA Type A Receptors.

The anesthetic etomidate modulates synaptic α1ß2/3γ2 GABAA receptors via binding sites located in transmembrane ß+/α- interfaces. Various approaches indicate that etomidate binds near ß2/3M286 side chains, including recent cryogenic electron microscopy images in α1ß2γ2L receptors under nonphysiologic conditions with ∼3.5-Å resolution. We hypothesized that substituted cysteine modification and protection experiments using variably sized n-alkyl-methanethiosulfonate (MTS) reagents could precisely estimate the distance between bound etomidate and ß3M286 side chains in activated functional receptors. Using voltage-clamp electrophysiology in Xenopus oocytes expressing α1ß3M286Cγ2L GABAA receptors, we measured functional changes after exposing GABA-activated receptors to n-alkyl-MTS reagents, from methyl-MTS to n-decyl-MTS. Based on previous studies using a large sulfhydryl reagent, we anticipated that cysteine modifications large enough to overlap etomidate sites would cause persistently increased GABA sensitivity and decreased etomidate modulation and that etomidate would hinder these modifications, reducing effects. Based on altered GABA or etomidate sensitivity, ethyl-MTS and larger n-alkyl-MTS reagents modified GABA-activated α1ß3M286Cγ2L GABAA receptors. Receptor modification by n-propyl-MTS or larger reagents caused persistently increased GABA sensitivity and decreased etomidate modulation. Receptor-bound etomidate blocked ß3M286C modification by n-propyl-MTS, n-butyl-MTS, and n-hexyl-MTS. In contrast, GABA sensitivity was unaltered by receptor exposure to methyl-MTS or ethyl-MTS, and ethyl-MTS modification uniquely increased etomidate modulation. These results reveal a "cut-on" between ethyl-MTS and n-propyl-MTS, from which we infer that -S-(n-propyl) is the smallest ß3M286C appendage that overlaps with etomidate sites. Molecular models of the native methionine and -S-ethyl and -S-(n-propyl) modified cysteines suggest that etomidate is located between 1.7 and 3.0 Å from the ß3M286 side chain. SIGNIFICANCE STATEMENT: Precise spatial relationships between drugs and their receptor sites are essential for mechanistic understanding and drug development. This study combined electrophysiology, a cysteine substitution, and n-alkyl-methanethiosulfonate modifiers, creating a precise molecular ruler to estimate the distance between a α1ß3γ2L GABA type A receptor residue and etomidate bound in the transmembrane ß+/α- interface.

Monod-Wyman-Changeux Allosteric Shift Analysis in Mutant α1ß3γ2L GABAA Receptors Indicates Selectivity and Crosstalk among Intersubunit Transmembrane Anesthetic Sites.

Propofol, etomidate, and barbiturate anesthetics are allosteric coagonists at pentameric α1ß3γ2 GABAA receptors, modulating channel activation via four biochemically established intersubunit transmembrane pockets. Etomidate selectively occupies the two ß +/α - pockets, the barbiturate photolabel R-5-allyl-1-methyl-5-(m-trifluoromethyl-diazirynylphenyl) barbituric acid (R-mTFD-MPAB) occupies homologous α +/ß - and γ +/ß - pockets, and propofol occupies all four. Functional studies of mutations at M2-15' or M3-36' loci abutting these pockets provide conflicting results regarding their relative contributions to propofol modulation. We electrophysiologically measured GABA-dependent channel activation in α1ß3γ2L or receptors with single M2-15' (α1S270I, ß3N265M, and γ2S280W) or M3-36' (α1A291W, ß3M286W, and γ2S301W) mutations, in the absence and presence of equipotent clinical range concentrations of etomidate, R-mTFD-MPAB, and propofol. Estimated open probabilities were calculated and analyzed using global two-state Monod-Wyman-Changeux models to derive log(d) parameters proportional to anesthetic-induced channel modulating energies (where d is the allosteric anesthetic shift factor). All mutations reduced the log(d) values for anesthetics occupying both abutting and nonabutting pockets. The Δlog(d) values [log(d, mutant) - log(d, wild type)] for M2-15' mutations abutting an anesthetic's biochemically established binding sites were consistently larger than the Δlog(d) values for nonabutting mutations, although this was not true for the M3-36' mutant Δlog(d) values. The sums of the anesthetic-associated Δlog(d) values for sets of M2-15' or M3-36' mutations were all much larger than the wild-type log(d) values. Mutant Δlog(d) values qualitatively reflect anesthetic site occupancy patterns. However, the lack of Δlog(d) additivity undermines quantitative comparisons of distinct site contributions to anesthetic modulation because the mutations impaired both abutting anesthetic binding effects and positive cooperativity between anesthetic binding sites.

Incidence of aspiration in infants with single-ventricle physiology following hybrid procedure.

BACKGROUND: Swallowing dysfunction is a known complication for infants with complex congenital heart disease (CHD), but few studies have examined swallowing outcomes following the hybrid procedure for stage 1 palliation in children with single ventricle physiology. OBJECTIVES: (1) Identify the incidence of aspiration in all infants with single ventricle physiology who underwent the hybrid procedure and (2) Compare results of clinical bedside and instrumental swallowing evaluations to examine the predictive value of a less invasive swallowing assessment for this population of high-risk infants. METHODS: This was a retrospective cohort chart review study. All patients with single-ventricle physiology who underwent the hybrid procedure received a referral for subsequent instrumental swallow assessment during a 4-year period. Results from clinical bedside evaluations were compared to those of the instrumental assessment. RESULTS: Fifty infants were included in this study. During instrumental swallow assessment, aspiration was observed in 28% of infants following the hybrid procedure. Normal swallowing function was identified in 44% of infants, and 28% demonstrated laryngeal penetration. Neither length of intubation nor prematurity were found to be predictors of aspiration. Thirty-six of these infants were assessed via clinical bedside evaluation prior to the instrumental evaluation. The sensitivity of the clinical bedside evaluation was 0.73 and the specificity was 0.92. CONCLUSIONS: This study reports on a cohort of infants with single ventricle physiology following the hybrid procedure and found the incidence of aspiration to be lower than previously reported. Improved clinical bedside evaluation guidelines are needed so that clinicians can predict more reliably which infants are at risk for aspiration following the hybrid procedure.

High-throughput Screening in Larval Zebrafish Identifies Novel Potent Sedative-hypnotics.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Many general anesthetics were discovered empirically, but primary screens to find new sedative-hypnotics in drug libraries have not used animals, limiting the types of drugs discovered. The authors hypothesized that a sedative-hypnotic screening approach using zebrafish larvae responses to sensory stimuli would perform comparably to standard assays, and efficiently identify new active compounds. METHODS: The authors developed a binary outcome photomotor response assay for zebrafish larvae using a computerized system that tracked individual motions of up to 96 animals simultaneously. The assay was validated against tadpole loss of righting reflexes, using sedative-hypnotics of widely varying potencies that affect various molecular targets. A total of 374 representative compounds from a larger library were screened in zebrafish larvae for hypnotic activity at 10 µM. Molecular mechanisms of hits were explored in anesthetic-sensitive ion channels using electrophysiology, or in zebrafish using a specific reversal agent. RESULTS: Zebrafish larvae assays required far less drug, time, and effort than tadpoles. In validation experiments, zebrafish and tadpole screening for hypnotic activity agreed 100% (n = 11; P = 0.002), and potencies were very similar (Pearson correlation, r > 0.999). Two reversible and potent sedative-hypnotics were discovered in the library subset. CMLD003237 (EC50, ~11 µM) weakly modulated γ-aminobutyric acid type A receptors and inhibited neuronal nicotinic receptors. CMLD006025 (EC50, ~13 µM) inhibited both N-methyl-D-aspartate and neuronal nicotinic receptors. CONCLUSIONS: Photomotor response assays in zebrafish larvae are a mechanism-independent platform for high-throughput screening to identify novel sedative-hypnotics. The variety of chemotypes producing hypnosis is likely much larger than currently known.

Alphaxalone Binds in Inner Transmembrane ß+-α- Interfaces of α1ß3γ2 γ-Aminobutyric Acid Type A Receptors.

BACKGROUND: Neurosteroids like alphaxalone are potent anxiolytics, anticonvulsants, amnestics, and sedative-hypnotics, with effects linked to enhancement of γ-aminobutyric acid type A (GABAA) receptor gating in the central nervous system. Data locating neurosteroid binding sites on synaptic αßγ GABAA receptors are sparse and inconsistent. Some evidence points to outer transmembrane ß-α interfacial pockets, near sites that bind the anesthetics etomidate and propofol. Other evidence suggests that steroids bind more intracellularly in ß-α interfaces. METHODS: The authors created 12 single-residue ß3 cysteine mutations: ß3T262C and ß3T266C in ß3-M2; and ß3M283C, ß3Y284C, ß3M286C, ß3G287C, ß3F289C, ß3V290C, ß3F293C, ß3L297C, ß3E298C, and ß3F301C in ß3-M3 helices. The authors coexpressed α1 and γ2L with each mutant ß3 subunit in Xenopus oocytes and electrophysiologically tested each mutant for covalent sulfhydryl modification by the water-soluble reagent para-chloromercuribenzenesulfonate. Then, the authors assessed whether receptor-bound alphaxalone, etomidate, or propofol blocked cysteine modification, implying steric hindrance. RESULTS: Eleven mutant ß3 subunits, when coexpressed with α1 and γ2L, formed functional channels that displayed varied sensitivities to the three anesthetics. Exposure to para-chloromercuribenzenesulfonate produced irreversible functional changes in ten mutant receptors. Protection by alphaxalone was observed in receptors with ß3V290C, ß3F293C, ß3L297C, or ß3F301C mutations. Both etomidate and propofol protected receptors with ß3M286C or ß3V290C mutations. Etomidate also protected ß3F289C. In α1ß3γ2L structural homology models, all these protected residues are located in transmembrane ß-α interfaces. CONCLUSIONS: Alphaxalone binds in transmembrane ß-α pockets of synaptic GABAA receptors that are adjacent and intracellular to sites for the potent anesthetics etomidate and propofol.

Estimated Cost-Effectiveness of Intensive Interdisciplinary Behavioral Treatment for Increasing Oral Intake in Children With Feeding Difficulties.

OBJECTIVE : To examine the cost-effectiveness of intensive interdisciplinary behavioral treatment (IIBT) to address severe pediatric feeding difficulties and lead to the removal or prevention of gastrostomy tubes (G tubes) from the perspective of the insurance company. METHODS : Costs associated with G tubes and IIBT were compiled from the available literature and national databases. Costs were updated to price at the start of 2015 to allow data from different years to be analyzed on the same scale. RESULTS : One-way sensitivity and two-way threshold analyses demonstrated that IIBT may be a cost-effective treatment for prevention and removal of G tubes over 5 and 10 years. DISCUSSION : Data from this study can be used to justify cost of services for IIBT, and programs can use these data to discuss conservative savings of IIBT based on their treatment model and level of effectiveness.

Tektin 2 is required for central spindle microtubule organization and the completion of cytokinesis.

During anaphase, the nonkinetochore microtubules in the spindle midzone become compacted into the central spindle, a structure which is required to both initiate and complete cytokinesis. We show that Tektin 2 (Tek2) associates with the spindle poles throughout mitosis, organizes the spindle midzone microtubules during anaphase, and assembles into the midbody matrix surrounding the compacted midzone microtubules during cytokinesis. Tek2 small interfering RNA (siRNA) disrupts central spindle organization and proper localization of MKLP1, PRC1, and Aurora B to the midzone and prevents the formation of a midbody matrix. Video microscopy revealed that loss of Tek2 results in binucleate cell formation by aberrant fusion of daughter cells after cytokinesis. Although a myosin II inhibitor, blebbistatin, prevents actin-myosin contractility, the microtubules of the central spindle are compacted. Strikingly, Tek2 siRNA abolishes this actin-myosin-independent midzone microtubule compaction. Thus, Tek2-dependent organization of the central spindle during anaphase is essential for proper midbody formation and the segregation of daughter cells after cytokinesis.

Live-cell analysis of mitotic spindle formation in taxol-treated cells.

Taxol functions to suppress the dynamic behavior of individual microtubules, and induces multipolar mitotic spindles. However, little is known about the mechanisms by which taxol disrupts normal bipolar spindle assembly in vivo. Using live imaging of GFP-alpha tubulin expressing cells, we examined spindle assembly after taxol treatment. We find that as taxol-treated cells enter mitosis, there is a dramatic re-distribution of the microtubule network from the centrosomes to the cell cortex. As they align there, the cortical microtubules recruit NuMA to their embedded ends, followed by the kinesin motor HSET. These cortical microtubules then bud off to form cytasters, which fuse into multipolar spindles. Cytoplasmic dynein and dynactin do not re-localize to cortical microtubules, and disruption of dynein/dynactin interactions by over-expression of p50 "dynamitin" does not prevent cytaster formation. Taxol added well before spindle poles begin to form induces multipolarity, but taxol added after nascent spindle poles are visible-but before NEB is complete-results in bipolar spindles. Our results suggest that taxol prevents rapid transport of key components, such as NuMA, to the nascent spindle poles. The net result is loss of mitotic spindle pole cohesion, microtubule re-distribution, and cytaster formation.

Centrosome duplication proceeds during mimosine-induced G1 cell cycle arrest.

Centrosome duplication must remain coordinated with cell cycle progression to ensure the formation of a strictly bipolar mitotic spindle, but the mechanisms that regulate this coordination are poorly understood. Previous work has shown that prolonged S-phase is permissive for centrosome duplication, but prolonging either G2 or M-phase cannot support duplication. To examine whether G1 is permissive for centrosome duplication, we release serum-starved G0 cells into mimosine, which delays the cell cycle in G1. We find that in mimosine, centrosome duplication does occur, albeit slowly compared with cells that progress into S-phase; centrosome duplication in mimosine-treated cells also proceeds in the absence of a rise in Cdk2 kinase activity normally associated with the G1/S transition. CHO cells arrested with mimosine can also assemble more than four centrioles (termed "centrosome amplification"), but the extent of centrosome amplification during prolonged G1 is decreased compared to cells that enter S-phase and activate the Cdk2-cyclin complex. Together, our results suggest a model, which predicts that entry into S-phase and the rise in Cdk2 activity associated with this transition are not absolutely required to initiate centrosome duplication, but rather, serve to entrain the centrosome reproduction cycle with cell cycle progression.