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Objective: The aim of this study was to determine which late-preterm (35-36 weeks' gestational age [GA]) and term neonates with early-onset hypoglycemia in the first 72 hours postnatal required a continuous glucose infusion to achieve and successfully maintain euglycemia., Study Design: This is a retrospective cohort study of late preterm and term neonates born in 2010-2014 and admitted to the Mother-Baby Unit at Parkland Hospital who had laboratory-proven blood glucose concentration < 40 mg/dL (2.2 mmol/L) during the first 72 hours of life. Among the subgroup needing intravenous (IV) glucose infusion, we analyzed which factors predicted a maximum glucose infusion rate (GIR) ≥ 10 mg/kg/min. The entire cohort was randomly divided into a derivation cohort ( n  = 1,288) and a validation cohort ( n  = 1,298)., Results: In multivariate analysis, the need for IV glucose infusion was associated with small size for GA, low initial glucose concentration, early-onset infection, and other perinatal variables in both cohorts. A GIR ≥ 10 mg/kg / min was required in 14% of neonates with blood glucose value < 20 mg/dL during the first 3 hours of observation. The likelihood of a GIR ≥ 10 mg/kg/min was associated with lower initial blood glucose value and lower umbilical arterial pH., Conclusion: Need for IV glucose infusion was associated with small size for GA, low initial glucose concentration, early-onset infection, and variables associated with perinatal hypoxia-asphyxia. The likelihood of a maximum GIR ≥ 10 mg/kg/min was greater in neonates with lower blood glucose value during the first 3 hours of observation and lower umbilical arterial pH., Key Points: · We studied 51,973 neonates ≥ 35 weeks' GA.. · We established a model predicting the need for IV glucose.. · We also predicted the need for a high rate of IV glucose.., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: Hyperhemolysis syndrome (HHS) is an uncommon transfusion reaction described in several hematologic disorders, including sickle cell disease (SCD). HHS is characterized by a decline in hemoglobin (Hb) values below pre-transfusion levels following transfusion of red blood cells (RBCs), coupled with laboratory markers consistent with hemolysis. The proposed pathophysiologic mechanisms underlying HHS include increased phosphatidylserine expression, macrophage activation, and complement dysregulation. Many pathophysiologic mechanisms thought to contribute to HHS have been similarly described in cases of severe COVID-19., Case Report: A 28-year-old male with a history of HbSS presented with shortness of breath, right-sided chest pain, and a two-day history of fever. Polymerase chain reaction (PCR) detected SARS-CoV-2 infection with the omicron variant. The patient required an RBC transfusion (pre-transfusion hemoglobin [Hb]5.8 g/dL) with an immediate post-transfusion Hb of 6.3 g/dL. However, Hb rapidly declined to 1.7 g/dL, and lactate dehydrogenase (LDH) rose to 8701 u/L. The absolute reticulocyte count of 538 × 10 9 /L correspondingly fell to 29 × 10 9 /L. Despite additional RBC transfusions and initiation of immunosuppressive therapy, he expired on Day 9(D9)., Conclusion: Given the similarities in their proposed pathophysiology, patients with SCD and concomitant SARS-CoV-2 infection may be predisposed to developing HHS., (Copyright © 2023. Published by Elsevier Ltd.)

Background: Hypoglycemia in neonates is common and contributes to 4.0-5.8% of neonatal intensive care unit (NICU) admissions. In utero nicotine exposure is underexplored as a potential contributor to neonatal hypoglycemia. Rat models have shown that in utero nicotine exposure can be associated with a reduction in pancreatic beta cell mass, leading to glucose dysregulation. The primary aim of this work is to study the risk of developing hypoglycemia after birth in a population of in utero nicotine-exposed neonates., Methods: We conducted a retrospective matched cohort study that augmented an existing dataset of neonates admitted to a level IV NICU with household-based in utero nicotine exposure (N = 335). Neonates in the control group parents denied household smoking (N = 325), were born within a 6-month timeframe, and were within a birthweight of 50 grams of a nicotine-exposed neonate. Data reviewed included gestational age, growth parameters, maternal history of diabetes, and glucose levels within the first three hours of life per unit protocol., Results: 660 neonates were included in the analysis. In utero nicotine exposure demonstrated a 94.3% posterior probability (PP) for greater hypoglycemia risk (RR = 1.185, 95% CrI = [0.953, 1.445]). A 94.6% PP was demonstrated when neonates who were small for gestational age, intrauterine growth-restricted, and born to diabetic mothers were excluded (n = 482; RR = 1.271, 95% CrI = [0.946, 1.669])., Conclusion: Nicotine exposure in utero was found to be a potential risk factor for developing hypoglycemia after birth. Mechanisms of action should be explored, and additional research on in utero nicotine exposure risks should follow.

Nitric oxide (NO) is a bioactive gas produced by one of the three NO synthases: neuronal NOS (nNOS), inducible (iNOS), and endothelial NOS (eNOS). NO has a relevant modulatory role in muscle contraction; this takes place through two major signaling pathways: (i) activation of soluble guanylate cyclase and, thus, protein kinase G or (ii) nitrosylation of sulfur groups of cysteine. Although it has been suggested that nNOS-derived NO is the responsible isoform in muscle contraction, the roles of eNOS and iNOS and their signaling pathways have not yet been clarified. To elucidate the action of each pathway, we optimized the generation of myooids, an engineered skeletal muscle tissue based on the C2C12 cell line. In comparison with diaphragm strips from wild-type mice, 180 myooids were analyzed, which expressed all relevant excitation-contraction coupling proteins and both nNOS and iNOS isoforms. Along with the biochemical results, myooids treated with NO donor (SNAP) and unspecific NOS blocker (L-NAME) revealed a comparable NO modulatory effect on force production as was observed in the diaphragm strips. Under the effects of pharmacological tools, we analyzed the myooids in response to electrical stimulation of two possible signaling pathways and NO sources. The nNOS-derived NO exerted its negative effect on force production via the sGG-PKG pathway, while iNOS-derived NO increased the excitability in response to sub-threshold electrical stimulation. These results strengthen the hypotheses of previous reports on the mechanism of action of NO during force production, showed a novel function of iNOS-derived NO, and establish the myooid as a novel and robust alternative model for pathophysiological skeletal muscle research., Competing Interests: Author L-MS was employed by the company PromoCell GmbH. Author LP was employed by the company myNEO NV. Author LE was employed by the company Immatics Biotechnology GmbH. The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Mosqueira, Scheid, Kiemel, Richardt, Rheinberger, Ollech, Lutge, Heißenberg, Pfitzer, Engelskircher, Yildiz and Porth.)

The in vitro motility assay (IVMA) is a powerful tool commonly used in basic muscle research and for drug screenings with the aim to find treatment options for neuromuscular disorders. In brief, the sliding movement of fluorescence-labeled actin filaments on myosin motor proteins is recorded, and the sliding velocity is analyzed via image analysis methods. Due to low signal-to-noise ratios and large variability in the velocity signal, accurate determination of the maximum sliding velocity is challenging. We introduce a new method and software program named Actin Phase Velocity (ActiPHV). The method extracts the maximum velocity from filament tracking data. Based on simulated and real reference data we show that our method yields a higher accuracy compared to previous methods. As a result, our method enables enhancing the sensitivity of the IVMA to better exploit its full potential.

Objectives: Determine sources of error in electronically extracted data from electronic health records., Study Design: Categorical and continuous variables related to early-onset neonatal hypoglycemia were preselected and electronically extracted from records of 100 randomly selected neonates within 3479 births with laboratory-proven early-onset hypoglycemia. Extraction language was written by an information technologist and data validated by blinded manual chart review. Kappa coefficient assessed categorical variables and percent validity continuous variables., Results: 8/23 (35%) categorical variables had acceptable Κappa (1-0.81); 5/23 (22%) had fair-slight agreement, Κappa < 0.40. Notably, "hypoglycemia" had poor agreement, Κappa 0.16. In contrast, 6/8 continuous variables had validity ≥ 94%. After correcting extraction language, 6/9 variables were corrected and inter-rater validation improved. However, "hypoglycemia" was not corrected, remaining an issue., Conclusions: Data extraction without validation procedures, especially categorical variables using International Classification of Diseases-9 (ICD-9) codes, often results in incorrect data identification. Electronically extracted data must incorporate built-in validating processes.

Objective: To determine the validity of screening and serial neutrophil counts in predicting the absence/presence of late-onset sepsis (LOS) in infants with central venous catheters., Study Design: Retrospective study of infants admitted to the neonatal intensive care unit (2009-2013) at Parkland Hospital with a central venous catheter and ≥1 LOS evaluations. Infants were categorized as proven or suspect LOS or uninfected based on results of blood cultures, clinical illness, and duration of antibiotics. Receiver operating curves (ROCs) were constructed to predict the absence or presence of LOS using Manroe reference ranges for total and immature neutrophils and the immature to total neutrophil ratio at 0, 12, and 24 hours after blood culture and the neutrophil value score, which assesses serial values., Results: Of the 497 infants with a central venous catheter, 179 underwent ≥1 LOS evaluations, and 140 of 179 (78%) had ≥1 complete evaluations (2 blood cultures and neutrophil values at 0, 12, and 24 hours), resulting in 188 complete LOS evaluations. The gestational age was 28 ± 4 weeks and LOS evaluation occurred at 29 ± 34 days (SD; 4-197 days). Sixty-one (35%) infants had proven LOS, 48 (23%) were suspect, and 71 (38%) were noninfected. ROC comparing proven vs noninfected was ≤0.56 for total neutrophils, immature neutrophils, and immature to total neutrophil ratio at 0, 12, and 24 hours and similar for proven + suspect vs noninfected. ROC for neutrophil value scores and absence of LOS was 0.56., Conclusions: Screening neutrophil values are poor predictors of LOS in neonates with a central venous catheter, as are serial neutrophils and the neutrophil value score. Alternative biomarkers are needed., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The in vitro motility assay (IVMA) is a technique that enables the measurement of the interaction between actin and myosin providing a relatively simple model to understand the mechanical muscle function. For actin-myosin IVMA, myosin is immobilized in a measurement chamber, where it converts chemical energy provided by ATP hydrolysis into mechanical energy. The result is the movement of fluorescently labeled actin filaments that can be recorded microscopically and analyzed quantitatively. Resulting sliding speeds and patterns help to characterize the underlying actin-myosin interaction that can be affected by different factors such as mutations or active compounds. Additionally, modulatory actions of the regulatory proteins tropomyosin and troponin in the presence of calcium on actin-myosin interaction can be studied with the IVMA. Zebrafish is considered a suitable model organism for cardiovascular and skeletal muscle research. In this context, straightforward protocols for the isolation and use of zebrafish muscle proteins in the IVMA would provide a useful tool in molecular studies. Currently, there are no protocols available for the mentioned purpose. Therefore, we developed fast and easy protocols for characterization of zebrafish proteins in the IVMA. Our protocols enable the interested researcher to (i) isolate actin from zebrafish skeletal muscle and (ii) extract functionally intact myosin from cardiac and skeletal muscle of individual adult zebrafish. Zebrafish tail muscle actin is isolated after acetone powder preparation, polymerized, and labeled with Rhodamine-Phalloidin. Myosin from ventricles of adult zebrafish is extracted directly into IVMA flow-cells. The same extraction protocol is applicable for comparably small tissue pieces as from zebrafish tail, mouse and frog muscle. After addition of the fluorescently labeled F-actin from zebrafish-or other origin-and ATP, sliding movement can be visualized using a fluorescence microscope and an intensified CCD camera. Taken together, we introduce a method for functional analysis in zebrafish cardiac and skeletal muscle research to study mutations at the molecular level of thick or thin filament proteins. Additionally, preliminary data indicate the usefulness of the presented method to perform the IVMA with myosin extracted from muscles of other animal models.

Aims: Regulatory proteins of the sarcomere are pivotal for normal heart function and when affected by mutations are frequently causing cardiomyopathy. The exact function of these regulatory proteins and how mutations in these translate into distinct cardiomyopathy phenotypes remains poorly understood. Mutations in the essential myosin light chain (ELC) are linked to human cardiomyopathy characterized by a marked variability in disease phenotypes and high incidences of sudden death. Here we studied the role of the highly conserved S195 phosphorylation site of ELC using heterozygous adult zebrafish lazy susan (laz(m647)) in regulating contractile function in normal physiology and disease., Methods and Results: Echocardiography revealed signs of systolic dysfunction in otherwise phenotypically unremarkable heterozygote mutants. However, after physical stress, heart function of laz heterozygous zebrafish severely deteriorated causing heart failure and sudden death. Mechanistically, we show that upon physical stress, ELCs become phosphorylated and lack of S195 dominant-negatively impairs ELC phosphorylation. In vitro motility analysis with native myosin from adult heterozygous hearts demonstrates that S195 loss, specifically following physical stress, results in altered acto-myosin sliding velocities and myosin binding cooperativity, causing reduced force generation and organ dysfunction., Conclusion: Using adult heterozygous zebrafish, we show that ELC S195 phosphorylation is pivotal for adaptation of cardiac function to augmented physical stress and we provide novel mechanistic insights into the pathogenesis of ELC-linked cardiomyopathy., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)