Suppression of crosstalk in multielectrode arrays with local shielding

Electrical crosstalk can constrain the performance of multielectrode arrays in electro- and neurophysiology, in terms of both stimulation and recording. This is especially so at high electrode density, desirable for spatiotemporal mapping of bioelectrical signals from multiple cells. Channel interference due to crosstalk is currently only partially addressed, via continuous interleaved sampling or post-data acquisition spike sorting. Here, we show that a locally-shielded electrode architecture significantly suppresses crosstalk, and enables multi-site recording at high electrode density without the need for spike sorting. Arrays of shielded electrodes, prepared by micro- and nanofabrication techniques in a vertically-oriented coaxial geometry, demonstrate at least a 400 times improvement in spatial density over the unshielded case.

Improved growth and developmental activity post tracheostomy in preterm infants with severe BPD

OBJECTIVES

To examine growth, sedation needs, and participation in developmental activities before and after tracheostomy among infants with severe bronchopulmonary dysplasia.

METHODS

Retrospective analysis of infants born at <32 weeks' gestation or birth weights <1500 g with severe BPD who underwent tracheostomy placement between January 1, 2010 and December 31, 2016 in a quaternary referral newborn and infant intensive care unit. Changes in growth parameters and frequency/type of participation in physical therapy sessions performed during the 4-weeks before tracheostomy and 4-weeks after the first tracheostomy tube change were compared.

RESULTS

A total of 72 patient were included in the study. Average weekly gain in weight, length, and head circumference were significantly higher during the 4-week period after compared to before tracheostomy. The most significant change occurred for linear growth (0.71 ± 0.40 cm/wk pre vs 0.97 ± 0.48 cm/wk pre, P < 0.001). Median Z score improved for weight (pre -1.42 [-3,10, -0.33] vs post -0.91 [-2.7, 0.27], P < 0.001), length (pre -3.07 [-4.39, -1.31] vs post -1.95 [-3.83, -0.93], P < 0.001) and weight-to-length ratio (pre 1.66 [0.58, 2.55] vs post 1.32 [0.17, 2.2], P = 0.02). Participation in developmental therapies significantly improved post tracheostomy (pre vs post: 5.2 ± 2.9 vs 8.7 ± 4.3 sessions performed over 4 weeks, P < 0.0001). Physical therapy sessions more often promoted developmental skill acquisition after tracheostomy compared to facilitating physiologic stability before tracheostomy. Daily sedation requirements decreased post tracheostomy.

CONCLUSIONS

Tracheostomy was associated with improved proportional growth and increased participation in activities promoting developmental skill acquisition and reduced daily sedation requirements in preterm infants with severe BPD.

Genotype Positive Long QT Syndrome in Patients With Coexisting Congenital Heart Disease

Congenital long QT syndrome (LQTS) is characterized by QT prolongation with predisposition to life-threatening arrhythmia. There have been sporadic reports of LQTS coexisting with more common forms of congenital heart disease (CHD). However, the diagnosis of LQTS when CHD is present may be confounded by several common variables including postoperative electromechanical factors predisposing to ventricular arrhythmia, intrinsic, and postoperative QRS abnormalities. This report documents a single-center experience with patients who have both genetically confirmed LQTS and CHD to examine their modes of presentation and factors associated with making the diagnosis of LQTS in this patient population, as well as potential confounding variables that may mask or delay both LQTS diagnosis and initiation of therapy. A retrospective review was performed of subjects with confirmed LQTS and associated CHD from 1999 to January 2017. Genetic analysis was performed predominantly using commercially available panel testing. A chart review included detailed analysis of electrocardiograms, 24-hour 3-lead rhythm monitors and exercise stress test tracings as well as the genetic test reports. QT intervals were measured using Bazett's formula. Eleven patients were identified. Four patients had LQTS type 1, 6 had LQTS type 2, and 1 had a disease-associated mutation in KCNQ1 and a variant of unknown significance in KCNH2 gene. Two patients had positive cascade screening. Arrhythmia presentations of the LQTS were at both extremes of the cohort age range (in-utero and midchildhood age). There was a seeming overrepresentation of conotruncal anomalies and/or arch anomalies, with 7 of the 11 patients. In conclusion, the diagnosis of LQTS may be challenging in the setting of CHD (a prolonged ST segment may be helpful), and high index of suspicion is required. The overall incidence of LQTS in CHD appears extremely rare, but the diagnosis and true incidence may be masked by confounding electrocardiogrpahic findings and other variables common in CHD.

Intraoperative Three-Dimensional Mapping of Supraventricular Tachycardia in a Young Fontan Patient

Preoperative tachycardia is uncommon before an initial Fontan procedure. Catheter intervention can risk complications in small patients. A patient with fetal tachycardia and double inlet left ventricle underwent Norwood and bidirectional Glenn procedures. She had persistent tachycardia. A three-dimensional electroanatomic mapping system was modified for the operative procedure; it was used to identify the arrhythmia substrate and cryoablate an atrioventricular nodal tachycardia. Mapping added 20 minutes to the operation. She is arrhythmia-free and off medication after 4 months. This three-dimensional system was successfully adapted for an intraoperative SVT ablation in this small patient, and it may be useful in other settings.

A Novel Method for Epicardial Defibrillator Lead Placement in Young Children: Coil Between the Great Arteries

The primary and secondary prevention of sudden cardiac death resulting from malignant arrhythmia, channelopathy, and hypertrophic cardiomyopathy often requires the implantation of automatic internal cardiac defibrillators (AICDs) in the pediatric population. In young patients, the small size of the systemic veins, complex anatomy of congenital heart disease, and body habitus often preclude safe and durable transvenous placement of the AICD coil, requiring innovative methods to circumvent this problem. This report describes the technique used at Rady Children's Hospital San Diego/UCSD for the epicardial placement of an ICD system with a transvenous ICD coil placed between the aorta and pulmonary artery, thereby producing a stable location and excellent coil-to-can vector for successful defibrillation.

Downmodulation of key inflammatory cell markers with a topical Janus kinase 1/2 inhibitor

BACKGROUND

INCB018424 is a novel, potent Janus kinase (JAK)1/JAK2 inhibitor that blocks signal transduction of multiple proinflammatory cytokines.

OBJECTIVES

To evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics and preliminary efficacy of topical INCB018424 phosphate cream in patients with plaque psoriasis.

METHODS

Topical INCB018424 phosphate 1·0% or 1·5% cream was applied once daily (QD) or twice daily (BID) for 4 weeks to 2-20% body surface area in five sequential cohorts of five patients aged 18-65 years. Target lesions were scored on a scale of 0-4 for erythema, scaling and thickness. Additionally, the overall disease activity in each patient was measured using Physician's Global Assessment. INCB018424 concentrations were measured in plasma, and cytokine stimulated phosphorylated signal transducer and activator of transcription 3 phosphorylation (pSTAT3) levels in peripheral blood cells were evaluated. Pretreatment and post-treatment skin biopsies were compared with healthy skin, including evaluation of histopathology, immunohistochemistry and mRNA expression.

RESULTS

Treatment with INCB018424 phosphate cream either 1·0% QD or 1·5% BID resulted in improvements in lesion scores. No significant inhibition of pSTAT3 in peripheral blood cells was observed following topical application, consistent with the generally low steady-state plasma concentrations of INCB018424 measured. Transcriptional markers of immune cell lineage/activation in lesional skin were reduced by topical INCB018424, with correlations observed between clinical improvement and decreases in markers of T helper 17 lymphocyte activation, dendritic-cell activation and epidermal hyperplasia. INCB018424 treatment reduced epidermal hyperplasia and dermal inflammation in most patient samples, with reductions in CD3, CD11c, Ki67 and keratin 16 observed by immunohistochemical analysis.

CONCLUSIONS

Topical INCB018424 dosed for 28 days QD or BID is pharmacologically active in patients with active psoriasis and modulates proinflammatory cytokines in the pathogenesis of psoriatic lesions.

Prediction of elementary school children's externalizing problem behaviors from attentional and behavioral regulation and negative emotionality

The purpose of this study was to examine the moderating role of individual differences in negative emotionality in the relations of behavioral and attentional (emotional) regulation to externalizing problem behaviors. Teachers' and one parent's reports of children's regulation (attentional and behavioral), emotionality, and problem behavior were obtained when children were in kindergarten to grade 3 and two years later (N = 169; 146 in major analyses); children's behavioral regulation also was assessed with a measure of persistence. According to the best fitting structural equation model, at two ages behavioral dysregulation predicted externalizing behavior problems for children both high and low in negative emotionality, whereas prediction of problem behavior from attentional control was significant only for children prone to negative emotionality. There were unique, additive effects of behavioral and attentional regulation for predicting problem behavior as well as moderating effects of negative emotionality for attentional regulation.

Regulation, emotionality, and preschoolers' socially competent peer interactions

In this study, the relations of regulatory control to the qualities of children's everyday peer interactions were examined. Effortful control (EC) and observations of peer interactions were obtained from 135 preschoolers (77 boys and 58 girls, mean ages = 50.88 and 50.52, respectively). The results generally confirmed the prediction that children who are high in EC were relatively unlikely to experience high levels of negative emotional arousal in response to peer interactions, but this relation held only for moderate to high intense interactions. Socially competent responding was less likely to be observed when the interaction was intense or when negative emotions were elicited. Moreover, when the interactions were of high intensity, highly regulated children were likely to evidence socially competent responses. The relation of EC and intensity to social competence was partially mediated by negative emotional arousal. The results support the conclusion that individual differences in regulation interact with situational factors in influencing young children's socially competent responding.

Using hyaluronic acid to create a fetal-like environment in vitro

The fetal wound healing matrix is exceptionally rich in hyaluronic acid (HA). Fetal wounds heal without scarring or contraction. Noting these observations, we cultured adult dermal explants in the presence of various concentrations of medical-grade HA in vitro. In the presence of HA, fibroblasts migrated from the dermal explant and multiplied more rapidly than control explants. Subsequently, sterile toothpicks were used to disrupt (wound) fibroblast monolayers mechanically and the rate of closure was monitored. Cells cultivated in the presence of 5 mg/ml of exogenous HA changed in morphology and closed the wound more quickly than control cultures. Cells surrounding the wound extended numerous podalic processes and showed increased interdigitation. The effect of HA on cell proliferation is usually discussed in terms of the mechanical effects HA exerts on cells and the extracellular matrix. The physiological effect of HA may lie in its ability to act as an accessory receptor in cooperative ligand-binding pathways. For example, HA may bind growth and/or other factors, and thereby increase the effective concentration of these factors at the cell surface.

Identification of Drosophila cytoskeletal proteins by induction of abnormal cell shape in fission yeast

To clone metazoan genes encoding regulators of cell shape, we have developed a functional assay for proteins that affect the morphology of a simple organism, the fission yeast Schizosaccharomyces pombe. A Drosophila melanogaster cDNA library was constructed in an inducible expression vector and transformed into S. pombe. When expression of the Drosophila sequences was induced, aberrant cell shapes were found in 0.2% of the transformed colonies. Four severe phenotypes representing defects in cytokinesis and/or cell shape maintenance were examined further. Each displayed drastic and specific reorganizations of the actin cytoskeleton. Three of the cDNAs responsible for these defects appear to encode cytoskeletal components: the actin binding proteins profilin and cofilin/actin depolymerizing factor and a membrane-cytoskeleton linker of the ezrin/merlin family. These results demonstrate that a yeast phenotypic screen efficiently identifies conserved genes from more complex organisms and sheds light on their potential in vivo functions.

Mental rotation: effects of dimensionality of objects and type of task

The original studies of mental rotation estimated rates of imagining rotations that were much slower when two simultaneously portrayed three-dimensional shapes were to be compared (R. Shepard & J. Metzler) than when one two-dimensional shape was to be compared with a previously learned two-dimensional shape (Cooper and her associates). In a 2 X 2 design, we orthogonally varied dimensionality of objects and type of task. Both factors affected reaction times. Type of task was the primary determiner of estimated rate of mental rotation, which was about three times higher for the single-stimulus task. Dimensionality primarily affected an additive component of all reaction times, suggesting that more initial encoding is required for three-dimensional shapes. In the absence of a satisfactory way of controlling stimulus complexity, the results are at least consistent with the proposal that once three-dimensional objects have been encoded, their rotation can be imagined as rapidly as the rotation of two-dimensional shapes.