Early Post-operative ECG Changes as a Predictor of Post-pericardiotomy Syndrome Following Atrial Septal Defect Repair.

To identify risk factors associated with post-pericardiotomy syndrome (PPS) in patients undergoing surgical repair of atrial septal defects (ASD). A single-center retrospective study. Tertiary academic hospital. Included were patients of all ages who underwent surgical ASD repair, while exclusion criteria included the absence of post-operative electrocardiogram (ECG), lack of follow-up post-discharge and factors hindering ECG interpretation. Demographic and clinical data, including ECG changes indicative of pericardial inflammation, were collected. The primary outcome measure was the development of PPS, determined based on the standardized European Society of Cardiology (ESC) criteria. Among 190 patients who underwent surgical ASD repair, 154 (81%) met the inclusion criteria. Of these, 25 (16%)in total developed PPS, of which 60% were ≥ 18 years of age and 56% female. Significant associations relating both early ECG changes and pre-discharge pericardial effusion with subsequent occurrence of PPS were found in both univariate and multivariate analyses. The study establishes correlations of both early post-operative ECG changes indicative of inflammation and pre-discharge pericardial effusion with subsequent occurrence of PPS in patients undergoing surgical ASD repair. Both utilizing the standardized ESC definition of PPS and incorporating a physician-validated ECG evaluation strengthened the methodologic approach in establishing these relationships. The results also highlight the importance of considering age as a potential risk factor for PPS. Further research is needed to validate these findings and explore additional risk factors predicting early identification and management of patients at high risk for PPS following surgical ASD repairs.

Assessing the utility of ultrasound-guided vascular access placement with longer catheters in critically ill pediatric patients.

BACKGROUND: Critically ill pediatric patients can have difficulty with establishing and maintaining stable vascular access. A long-dwelling peripheral intravenous catheter placement decreases the need for additional vascular interventions. AIM: The study sought to compare longevity, catheter-associated complications, and the need for additional vascular interventions when using ultrasound-guided longer peripheral intravenous catheters comparing to a traditional approach using standard-sized peripheral intravenous catheters in pediatric critically ill patients with difficult vascular access. METHODS: This single-center retrospective cohort study included children 0-18 years of age with difficult vascular access admitted to the pediatric intensive care unit between 01/01/2018-06/01/2021. RESULTS: One hundred and eighty seven placements were included in the study, with 99 ultrasound-guided long intravenous catheters placed and 88 traditionally placed standard-sized intravenous catheters. In the univariate analysis, patients in the traditional approach were at a higher risk of intravenous failure compared to those in the ultrasound-guided approach (HR = 2.20, 95% CI [1.45-3.34], p = .001), with median intravenous survival times of 108 and 219 h, respectively. Adjusting for age, patients in the traditional approach remained at higher risk of intravenous failure (HR = 1.99, 95% CI: [1.28-3.08], p = .002). Adjusting for hospital length of stay, patients in the ultrasound-guided approach were less likely to have additional peripheral intravenous access placed during hospitalization (OR = 0.39, 95% CI [0.18-0.85] p = .017). CONCLUSION: In critically ill pediatric patients with difficult vascular access, ultrasound-guided long peripheral intravenous catheters provide an alternative to traditional approach standard-sized intravenous catheters with improved longevity, lower failure rates, and reduced need for additional vascular interventions.

Inhaled nitric oxide therapy for severe hypoxemia in hyperinflated mechanically ventilated bronchiolitis patient.

Management of hospitalized bronchiolitis patients comprises supportive care including non-invasive and invasive mechanical ventilation. Inhaled nitric oxide (iNO) therapy has been used in bronchiolitis patients to manage pulmonary hypertension, acute respiratory distress syndrome, bronchoconstriction or inflammation. We report the role of iNO in management of severe hypoxemia in a 7-month-old mechanically ventilated bronchiolitis patient on 100% oxygen and high ventilator settings who had hyperinflation on chest x-ray, and diffuse bronchospasm on clinical assessment. We believe iNO improved hypoxemia in our patient by optimizing the ventilation/perfusion mismatch, decreasing dead space ventilation and relieving elevated pulmonary vascular resistance associated with alveolar overdistention. Inhaled nitric oxide therapy for severe hypoxemia in hyperinflated mechanically ventilated bronchiolitis patient.

Dead space ratio as a tool in nitric oxide weaning: a study in pulmonary hypertensive disease.

OBJECTIVES: To describe the association between successful weaning of inhaled nitric oxide and trends in dead space ratio during such weans in patients empirically initiated on nitric oxide therapy out of concern of pulmonary hypertensive crisis. PATIENTS: Children in a cardiac intensive care unit initiated on inhaled nitric oxide out of clinical concern for pulmonary hypertensive crisis retrospectively over 2 years. MEASUREMENTS AND MAIN RESULTS: Twenty-seven patients were included, and nitric oxide was successfully discontinued in 23/27. These patients exhibited decreases in dead space ratio (0.18 versus 0.11, p = 0.047) during nitric oxide weaning, and with no changes in dead space ratio between pre- and post-nitric oxide initiation (p = 0.88) and discontinuation (p = 0.63) phases. These successful patients had a median age of 10 months [4.0, 57.0] and had a pre-existent diagnosis of CHD in 6/23 and pulmonary hypertension in 2/23. Those who failed nitric oxide discontinuation trended with a higher dead space ratio at presentation (0.24 versus 0.10), were more likely to carry a prior diagnosis of pulmonary hypertension (50% versus 8.7%), and had longer mechanical ventilation days (5 versus 12). CONCLUSIONS: Patients empirically placed on nitric oxide out of concern of pulmonary hypertensive crisis and successfully weaned off showed unchanged or decreased dead space ratio throughout the initiation to discontinuation phases of nitric oxide therapy. Trends in dead space ratio may aid in determining true need for nitric oxide and facilitate effective weaning. Further studies are needed to directly compare trends between success and failure groups.

Asynchrony During Pediatric Noninvasive Ventilation With a Nasal Cannula Interface: A Lung Model Study.

BACKGROUND: Pediatric noninvasive ventilation (NIV) is used commonly in the acute care setting and is associated with high incidence of patient ventilator asynchrony. METHODS: An ASL 5000 breathing simulator was used to model pediatric patients with varying patient efforts and lung conditions. For delivery of NIV, a commonly used acute care ventilator was used by connecting a nasal cannula interface to model nares produced with a 3-dimensional printer. The modes of ventilation were NIV pressure control continuous mandatory ventilation and NIV pressure control continuous spontaneous ventilation. Patient and ventilator waveforms were analyzed using the ASL 5000 software to assess for asynchrony events and determine the asynchrony index (AI). RESULTS: Significant asynchrony (AI > 0.1) existed in the majority of scenarios for both pressure control continuous mandatory ventilation and pressure control continuous spontaneous ventilation (79% and 93%, respectively). The most common asynchrony event was ineffective trigger, accounting for 81.9% of events in pressure control continuous mandatory ventilation and 79.3% in pressure control continuous spontaneous ventilation. There were no statistically significant differences in the AI when comparing simulated patient effort or lung condition. CONCLUSIONS: Significant asynchrony exists during NIV with a commonly used acute care ventilator and nasal cannula interface, which raises questions regarding its utility in clinical practice in the pediatric population.

Flow-induced Shear Stress Confers Resistance to Carboplatin in an Adherent Three-Dimensional Model for Ovarian Cancer: A Role for EGFR-Targeted Photoimmunotherapy Informed by Physical Stress.

A key reason for the persistently grim statistics associated with metastatic ovarian cancer is resistance to conventional agents, including platinum-based chemotherapies. A major source of treatment failure is the high degree of genetic and molecular heterogeneity, which results from significant underlying genomic instability, as well as stromal and physical cues in the microenvironment. Ovarian cancer commonly disseminates via transcoelomic routes to distant sites, which is associated with the frequent production of malignant ascites, as well as the poorest prognosis. In addition to providing a cell and protein-rich environment for cancer growth and progression, ascitic fluid also confers physical stress on tumors. An understudied area in ovarian cancer research is the impact of fluid shear stress on treatment failure. Here, we investigate the effect of fluid shear stress on response to platinum-based chemotherapy and the modulation of molecular pathways associated with aggressive disease in a perfusion model for adherent 3D ovarian cancer nodules. Resistance to carboplatin is observed under flow with a concomitant increase in the expression and activation of the epidermal growth factor receptor (EGFR) as well as downstream signaling members mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) and extracellular signal-regulated kinase (ERK). The uptake of platinum by the 3D ovarian cancer nodules was significantly higher in flow cultures compared to static cultures. A downregulation of phospho-focal adhesion kinase (p-FAK), vinculin, and phospho-paxillin was observed following carboplatin treatment in both flow and static cultures. Interestingly, low-dose anti-EGFR photoimmunotherapy (PIT), a targeted photochemical modality, was found to be equally effective in ovarian tumors grown under flow and static conditions. These findings highlight the need to further develop PIT-based combinations that target the EGFR, and sensitize ovarian cancers to chemotherapy in the context of flow-induced shear stress.

Interleukin-27: a novel biomarker in predicting bacterial infection among the critically ill.

INTRODUCTION: A continued need exists for effective diagnostic biomarkers in bacterial sepsis among critically ill patients, despite increasing use of available biomarkers such as procalcitonin (PCT). Interleukin-27 (IL-27) has shown early promise in a recent preliminary study, exhibiting high specificity and positive predictive values for bacterial infection in critically ill children. This validation study was performed to assess the value of IL-27 in predicting bacterial infection among patients admitted to the pediatric intensive care unit and to compare its performance with that of PCT. METHODS: A single-center (n = 702) prospective study was performed comparing both IL-27 and PCT levels between bacterially infected and uninfected cohorts in the pediatric intensive care unit. Infected status was determined by a chart review by an intensivist blinded to biomarker results. Formal performance comparisons included calculations of receiver operating characteristic (ROC) curves for IL-27 and PCT individually in addition to a combination strategy using a decision tree generated by classification and regression tree (CART) methodology. Secondary analysis focusing on subjects with documented bloodstream infections was performed. RESULTS: The overall infection rate was 27 %. ROC curves for the primary analysis yielded areas under the curve (AUCs) of 0.64 (0.59 to 0.68) for IL-27 and 0.61 (0.56 to 0.65) for PCT. Secondary analysis defining infected status exclusively through positive blood cultures yielded AUCs of 0.75 (0.68 to 0.81) for IL-27 and 0.64 (0.57 to 0.71) for PCT, with a specificity of 95 % (92 % to 97 %) for the prior established IL-27 cut-point value of at least 5.0 ng/ml. Similar AUCs were found for the subset of immunocompromised patients. In a CART-derived analysis taking immunocompromised status into consideration, a combination of IL-27 and PCT yielded an AUC of 0.81 (0.75 to 0.86), statistically improved from either IL-27 or PCT alone. CONCLUSIONS: Despite having a modest predictive value for infection independent of source, IL-27 may serve as a useful biomarker in estimating risk of bacterial infection among critically ill pediatric patients with bloodstream infections. In particular, among immunocompromised subjects, this diagnostic biomarker may be helpful either alone or using a combination strategy with other available biomarkers.

Longitudinal measurement of extracellular matrix rigidity in 3D tumor models using particle-tracking microrheology.

The mechanical microenvironment has been shown to act as a crucial regulator of tumor growth behavior and signaling, which is itself remodeled and modified as part of a set of complex, two-way mechanosensitive interactions. While the development of biologically-relevant 3D tumor models have facilitated mechanistic studies on the impact of matrix rheology on tumor growth, the inverse problem of mapping changes in the mechanical environment induced by tumors remains challenging. Here, we describe the implementation of particle-tracking microrheology (PTM) in conjunction with 3D models of pancreatic cancer as part of a robust and viable approach for longitudinally monitoring physical changes in the tumor microenvironment, in situ. The methodology described here integrates a system of preparing in vitro 3D models embedded in a model extracellular matrix (ECM) scaffold of Type I collagen with fluorescently labeled probes uniformly distributed for position- and time-dependent microrheology measurements throughout the specimen. In vitro tumors are plated and probed in parallel conditions using multiwell imaging plates. Drawing on established methods, videos of tracer probe movements are transformed via the Generalized Stokes Einstein Relation (GSER) to report the complex frequency-dependent viscoelastic shear modulus, G*(ω). Because this approach is imaging-based, mechanical characterization is also mapped onto large transmitted-light spatial fields to simultaneously report qualitative changes in 3D tumor size and phenotype. Representative results showing contrasting mechanical response in sub-regions associated with localized invasion-induced matrix degradation as well as system calibration, validation data are presented. Undesirable outcomes from common experimental errors and troubleshooting of these issues are also presented. The 96-well 3D culture plating format implemented in this protocol is conducive to correlation of microrheology measurements with therapeutic screening assays or molecular imaging to gain new insights into impact of treatments or biochemical stimuli on the mechanical microenvironment.

Pediatric sepsis: challenges and adjunctive therapies.

Sepsis remains an important challenge in pediatric critical care medicine. This review provides an appraisal of adjunctive therapies for sepsis and highlights opportunities for meeting selected challenges in the field. Future clinical studies should address long-term and functional outcomes as well as acute outcomes. Potential adjunctive therapies such as corticosteroids, hemofiltration, hemoadsorption, and plasmapheresis may have important roles, but still require formal and more rigorous testing by way of clinical trials. Finally, the design of future clinical trials should consider novel approaches for stratifying outcome risks as a means of improving the risk-to-benefit ratio of experimental therapies.

Lewis X-containing neoglycoproteins mimic the intrinsic ability of zona pellucida glycoprotein ZP3 to induce the acrosome reaction in capacitated mouse sperm.

The binding of zona pellucida (ZP) glycoprotein ZP3 to mouse sperm surface receptors is mediated by protein-carbohydrate interactions. Subsequently, ZP3 induces sperm to undergo the acrosome reaction, an obligatory step in fertilization. We have previously identified Lewis X (Le(x); Gal beta 4[Fuc alpha 3]GlcNAc) as a potent inhibitor of in vitro sperm-ZP binding (Johnston et al. J Biol Chem 1998; 273:1888-1895). This glycan is recognized by approximately 70% of the ZP3 binding sites on capacitated, acrosome-intact mouse sperm, whereas Lewis A (Le(a); Gal beta 3[Fuc alpha 4]GlcNAc) is recognized by most of the remaining sites (Kerr et al. Biol Reprod 2004; 71:770-777). Herein, we test the hypothesis that Le(x)- and Le(a)-containing glycans, when clustered on a neoglycoprotein, bind ZP3 receptors on sperm and induce sperm to undergo the acrosome reaction via the same signaling pathways as ZP3. Results show that a Le(x)-containing neoglycoprotein induced the acrosome reaction in a dose-dependent and capacitation-dependent manner. A Le(a)-containing neoglycoprotein also induced sperm to undergo the acrosome reaction but was less potent than Le(x)-containing neoglycoproteins. In contrast, neoglycoproteins containing beta4-lactosamine (Gal beta 4GlcNAc), Lewis B (Fuc alpha 2Gal beta 3[Fuc alpha 4]GlcNAc), and sialyl-Le(x) glycans were inactive, as were four other neoglycoproteins with different nonfucosylated glycans. Consistent with these results, unconjugated Le(x)- and Le(a)-capped glycans were dose-dependent inhibitors, which at saturation, reduced the ZP-induced acrosome reaction by about 60% and 30%, respectively. Experiments utilizing pharmacological inhibitors suggest that induction of the acrosome reaction by solubilized ZP and Le(x)- and Le(a)-containing neoglycoproteins require the same calcium-dependent pathway. However, only the ZP-induced acrosome reaction requires a functional G(i) protein. Thus, Le(x)-containing neoglycoproteins bind to a major class of ZP3 receptors on capacitated sperm. A Le(a)-containing neoglycoprotein binds a second ZP3 receptor but is a less-potent inducer of the acrosome reaction.

Lewis X-containing glycans are specific and potent competitive inhibitors of the binding of ZP3 to complementary sites on capacitated, acrosome-intact mouse sperm.

Mammalian fertilization requires a cascade of interactions between sperm and the egg's zona pellucida (ZP). O-linked glycans on mouse glycoprotein ZP3 have been implicated in mediating one step of the fertilization process, the firm adhesion of acrosome-intact sperm to the ZP. Experiments to identify structural requirements of a sperm-binding glycan have demonstrated that a Lewis X (Le(x))-containing glycan (Gal beta 4[Fuc alpha 3]GlcNAc-R) was a potent, competitive inhibitor of in vitro sperm-ZP binding (Johnston et al. J Biol Chem 1998; 273: 1888-1895). However, those experiments did not define the particular step in the fertilization pathway that was blocked. The experiments described herein test the hypothesis that Le(x)-containing glycans are specific, competitive inhibitors of the binding of Alexa Fluor 568 fluorochrome (Alexa(568))-labeled ZP3 to sperm and, thus, bind the same sperm surface sites as ZP3. Dose-response analyses demonstrated that these glycans are potent inhibitors (IC(50) approximately 180 nM), which at saturation, reduced Alexa(568)-ZP3 binding by approximately 70%. A Lewis A (Le(a))-capped glycan (Gal beta 3[Fuc alpha 4]GlcNAc) was also a potent inhibitor (IC(50) approximately 150-200 nM), but at saturation, it reduced Alexa(568)-ZP3 binding by only 30%. In contrast, nonfucosylated glycans with nonreducing GlcNAc beta 4 or Gal beta 4 residues did not compete; neither did sialyl-Le(x) (Neu5Ac alpha 3Gal beta 4[Fuc alpha 3]GlcNAc-Lewis X) nor sulfo-Le(x) (3'-O-SO(3)-Lewis X). However, at saturation, Gal alpha 3Gal beta 4GlcNAc beta 3Gal beta 4Glc reduced Alexa(568)-ZP3 binding by approximately 70% but with moderate apparent affinity (IC(50) approximately 3000 nM). Fluorescence microscopy revealed that Alexa(568)-labeled Le(x)-Lac-BSA, Le(a)-Lac-BSA, and ZP3 bound to the same sperm surface domains. However, Le(a)-Lac did not inhibit binding of Alexa(568)-Le(x)-Lac-BSA, and Le(x)-Lac did not inhibit binding of Alexa(568)-Le(a)-Lac-BSA. Finally, Le(x)-Lac and Le(a)-Lac had an additive inhibitory effect on Alexa(568)-ZP3 binding. Thus, Le(x) is a ligand for a major class of ZP3 binding sites on mouse sperm, whereas Le(a) binding defines a different but less-abundant class of sites.

Characterization of zona pellucida glycoprotein 3 (ZP3) and ZP2 binding sites on acrosome-intact mouse sperm.

There is considerable evidence that mouse fertilization requires the binding of sperm to two of the three glycoproteins that form the zona pellucida (ZP), ZP3 and ZP2. Despite the biologic importance of this binding, no one has demonstrated that sperm express separate, saturable, and specific binding sites for ZP3 and for ZP2. Such a demonstration is a prerequisite for defining the distribution, numbers, affinities, and regulation of function of ZP3 and ZP2 binding sites on sperm. The experiments reported herein used fluorochrome-labeled ZP3 and ZP2 and quantitative image analysis to characterize the saturable binding of ZP3 and ZP2 to distinct sites on living, capacitated, acrosome-intact mouse sperm. Approximately 20% of the ZP3 binding sites were found over the acrosomal cap, and the remaining sites were located over the postacrosomal region of the head. In contrast, ZP2 binding sites were detected only over the postacrosomal region. Saturation analysis estimated numbers and affinities of the binding sites for ZP3 (B(max) approximately 185 000 sites per sperm; K(d) approximately 67 nM) and ZP2 (B(max) approximately 500 000 sites per sperm; K(d) approximately 200 nM). Use of unlabeled ZP3, ZP2, and ZP1 as competitive inhibitors of the binding of fluorochrome-labeled ZP3 and ZP2 demonstrated that ZP3 and ZP2 bound specifically to their respective sites on sperm. Finally, we demonstrate that extracellular calcium as well as capacitation and maturation of sperm are required for these sites to bind their respective ligands.

Discurso del Embajador William Hanna.

Abertura e boas vindas aos participantes.