Shape of Pulmonary Artery Doppler Flow Profile and Right Ventricular Hemodynamics in Neonates

OBJECTIVES

To characterize pulmonary artery Doppler flow profile (PAFP) patterns among infants receiving care in neonatal intensive care units and to examine the association of PAFP patterns with pulmonary and right ventricular (RV) hemodynamics.

STUDY DESIGN

This is a retrospective study at 2 tertiary intensive care units over 4 years that included neonates who demonstrated a complete tricuspid regurgitation envelope on targeted neonatal echocardiography. Separate personnel reviewed TNEs to characterize PAFP patterns, divide cohort into PAFP groups, and measure quantitative indices of RV hemodynamics (RV systolic pressure, pulmonary artery acceleration time and its ratio with RV ejection time, tricuspid annular plane systolic excursion, and RV output), for intergroup comparisons.

RESULTS

We evaluated TNEs from 186 neonates with median gestational age of 28.5 weeks (IQR, 25.9-35.9 weeks). Four distinct PAFP patterns were identified (A) near-isosceles triangle (22%), (B) right-angled triangle (29%), (C) notching (40%), and (D) low peak velocity (<0.4 m/s; 9%). Groups A-C demonstrated a stepwise worsening in all indices of PH, whereas pattern D was associated with lower tricuspid annular plane systolic excursion and RV output. Using common definitions of pulmonary hypertension (PH), pattern A performed best to rule out PH (sensitivity range, 81%-90%) and pattern C for diagnosing PH (specificity range, 63%-78%).

CONCLUSIONS

Inspection of PAFP is a simple bedside echocardiography measure that provides clinically meaningful information on underlying RV hemodynamics and may aid in screening and monitoring of patients for PH in intensive care units.

Challenges in clinical identification of right ventricular dysfunction in preterm infants with persistent pulmonary hypertension of the newborn

BACKGROUND

Right ventricular dysfunction, typically qualitatively diagnosed (Q-RVd) in preterm infants, requires echocardiography which is not always acutely available. We aimed to identify clinical indices of Q-RVd in very preterm infants (gestational age, GA <32 weeks) with persistent pulmonary hypertension of newborn (PPHN) and examine the reliability and validity of Q-RVd.

METHODS

Forty-seven infants with mean ± SD GA of 26.8 ± 2.7 weeks who had targeted neonatal echocardiography (TNE) ≤72 h old, during PPHN, were retrospectively studied. Three standard TNE clips were reviewed by two blinded assessors, and infants categorized as Q-RVd if moderate-severe RVd was diagnosed on ≥2 clips. Cardiopulmonary clinical indices at TNE and quantitative RV functional markers were compared between Q-RVd vs. no-RVd groups. Potential quantitative RVd definitions examined by classifying each measurement as "low" or "normal" using published data. Inter-rater agreement for Q-RVd assessed using Kappa statistics.

RESULTS

Mean age at TNE was 25.3 ± 20.4 h with Q-RVd diagnosed in 19(40 %) infants. Q-RVd group demonstrated higher peak oxygen requirements (96 ± 9 % vs. 84 ± 16 %, p < 0.01); however, no clinical parameters at TNE differentiated the groups. Quantitative measures were lower in Q-RVd patients, confirming classification validity. Among tested quantitative definitions, low RV stroke volume was associated with lower systolic blood pressure (41±7 vs. 47±9 mmHg, p = 0.02) and higher shock index (4.02±0.80 vs. 3.44±0.72, p = 0.02). Kappa for Q-RVd was 0.55 (95%CI 0.32-0.77).

CONCLUSIONS

The non-specific nature of clinical markers of RVd in preterm infants with PPHN necessitates echocardiographic diagnosis of RVd. Studies should examine prognostic relevance of RVd and establish outcome-based quantitative definitions in preterm infants.

Corticosteroid use in neonatal hypotension: A survey of Canadian neonatologists

OBJECTIVE

To assess prescribing practices and perspectives regarding the use of corticosteroids in the management of neonatal hypotension.

METHODS

Cross-sectional questionnaire-based electronic survey of neonatologists (n = 206) practicing at tertiary neonatal intensive care units across 30 academic centres in Canada.

RESULTS

The overall response rate was 33% (72/206), with a completion rate was 94%. Most (48/72, 64%) worked in a unit that covered both inborn and outborn infants, and 53% (37/70) worked in units with >100 very low birth weight infants admitted annually. Among the 72 respondents, 39% use a loading dose, of whom most (57%) use 2 mg/kg. Dosing ranges were variable, most using either 0.5 mg/kg or 1 mg/kg, q6h. Among the 56% (40/72) of neonatologists who reported measuring cortisol before initiation of hydrocortisone, cut-offs for initiation of hydrocortisone varied from <100 to <500 nmol/L, most of whom (48%) used <100 nmol/L. Of 71 respondents, 92% (65) indicated that a randomized control trial examining the use of corticosteroids in neonatal hypotension is needed, of whom 52% (37) indicated that the intervention group should receiving hydrocortisone after one vasopressor/inotrope.

CONCLUSIONS

This survey provides insight into the prescribing practices of tertiary neonatologists with regards to the use of corticosteroids in neonatal hypotension. While corticosteroids are frequently prescribed, there is variability in the indication, dosing, and duration of corticosteroid use. The findings from this survey can be used to inform further research, including a clinical trial, regarding the practice in the management of neonatal hypotension.

Organ dysfunction and mortality in preterm neonates with late-onset bloodstream infection

BACKGROUND

Organ dysfunction (ODF) in late-onset bloodstream infection (LBSI) is associated with increased risk of adverse outcomes. However, no established definition of ODF exists among preterm neonates. Our objective was to describe an outcome-based ODF definition for preterm infants, and assess factors associated with mortality.

METHODS

This is a six-year retrospective study of neonates <35 weeks gestational age, >72 h of age, with non-CONS bacterial/fungal LBSI. Discriminatory ability of each parameter for mortality was evaluated: base deficit ≤-8 mmol/L (BD8), renal dysfunction (urine output <1 cc/kg/h or creatinine ≥100 μmol/L), hypoxic respiratory failure (HRF, ventilated, FiO2 = 1.0), or vasopressor/inotrope use (V/I). Multivariable logistic regression analysis was performed to derive a mortality score.

RESULTS

One hundred and forty-eight infants had LBSI. BD8 had the highest individual predictive ability for mortality (AUROC = 0.78). The combination BD8 + HRF + V/I was used to define ODF (AUROC = 0.84). Fifty-seven (39%) infants developed ODF, among which 28 (49%) died. Mortality increased inversely relative to GA at LBSI-onset (aOR 0.81 [0.67, 0.98]) and directly relative to ODF occurrence (12.15 [4.48, 33.92]). Compared to no-ODF, ODF infants had lower GA and age at illness, and higher frequency of Gram-negative pathogen.

CONCLUSIONS

Among preterm neonates with LBSI, significant metabolic acidosis, HRF, and vasopressor/inotrope use may identify infants high risk for mortality. These criteria could help identify patients for future studies of adjunctive therapies.

IMPACT

Sepsis-related organ dysfunction is associated with increased risk of adverse outcomes. Among preterm neonates, significant metabolic acidosis, use of vasopressors/inotropes, and hypoxic respiratory failure may identify high-risk infants. This can be used to target research and quality improvement efforts toward the most vulnerable infants.

Dopamine or norepinephrine for sepsis-related hypotension in preterm infants: a retrospective cohort study

The purpose of this study is to compare the clinical effectiveness of dopamine (DA) versus norepinephrine (NE) as first-line therapy for sepsis-related hypotension in preterm infants. This is a retrospective cohort study over 10 years at two tertiary neonatal units. Preterm infants born < 35 weeks post-menstrual age (PMA), who received DA or NE as primary therapy for hypotension during sepsis, defined as culture-positive or culture-negative infections or necrotizing enterocolitis (NEC), were included. Episode-related mortality (< 7 days from treatment), pre-discharge mortality, and major morbidities among survivors were compared between two groups. Analyses were adjusted using the inverse probability of treatment weighting estimated by propensity score (PS). A total of 156 infants were included, 113 received DA and 43 NE. The mean ± SD PMA at birth and at treatment for the DA and NE groups were 25.8 ± 2.3 vs. 25.2 ± 2.0 weeks and 27.7 ± 3.0 vs. 27.1 ± 2.6 weeks, respectively (p > 0.05). Pre-treatment, the NE group had higher mean airway pressure (14 ± 4 vs. 12 ± 4 cmH₂O), heart rate (185 ± 17 vs. 175 ± 17 beats per minute), and median (IQR) fraction of inspired oxygen [0.67 (0.42, 1.0) vs. 0.52 (0.32, 0.82)] (p < 0.05 for all). After PS adjustment, NE was associated with lower episode-related mortality [adjusted odds ratio (95% CI) 0.55 (0.33, 0.92)], pre-discharge mortality [0.60 (0.37, 0.97)], post-illness new diagnosis of significant neurologic injury [0.32 (0.13, 0.82)], and subsequent occurrence of NEC/sepsis among the survivors [0.34, (0.18, 0.65)].

CONCLUSION

NE may be more effective than DA for management of sepsis-related hypotension among preterm infants. These data provide a rationale for prospective evaluation of these commonly used agents.

WHAT IS KNOWN

•Dopamine is the commonest vasoactive agent used to support blood pressure among preterm infants. •For adult patients, norepinephrine is recommended as the preferred therapy over dopamine for septic shock.

WHAT IS NEW

•This is the first study examining the relative clinical effectiveness of dopamine and norepinephrine as first-line pharmacotherapy for sepsis-related hypotension among preterm infants. •Norepinephrine use may be associated with lower mortality and morbidity than dopamine in preterm infants with sepsis.

Validity of the vasoactive-inotropic score in preterm neonates receiving cardioactive therapies

BACKGROUND

Vasoactive-Inotropic Score (VIS) is a weighted sum of various vasopressors and inotropes; its utility among preterm neonates is understudied.

OBJECTIVE

To investigate the association between maximum VIS (VIS^max) during the first 12, 24 and 48 h of treatment among preterm neonates who received vasopressors/inotropes, and the composite outcome of death/severe neuroinjury (sNI).

METHODS

Retrospective cohort study, over 6-years, including neonates <35 weeks gestational age (GA). Infants who met the primary composite outcome of death or sNI (defined as new intraventricular hemorrhage ≥grade 3 or periventricular leukomalacia) were compared to those who survived without sNI. Maximum VIS was categorized as <10, 10-19 or ≥ 20 for comparison.

RESULTS

192 infants (mean GA and birth weight 26.8 ± 3.3 weeks and 952 ± 528 g, respectively) were included. The most common primary diagnosis was sepsis/necrotizing enterocolitis (69 %). Median VIS for the entire cohort was 10. Death/sNI was associated with lower GA at birth and treatment, as well as higher frequency of VIS^max of 10-19 or ≥20, compared to <10, during each time period (all p < 0.01). Multivariable regression revealed GA at treatment and VIS^max ≥ 20 [not 10-19, referenced to <10] were associated death/sNI; adjusted odds ratio (95 % CI) for VIS^max ≥ 20 within 12, 24, and 48 h were 4.2 (1.6-11.0), 4.9 (1.9-12.3), and 6.7 (2.7-16.7), respectively.

CONCLUSIONS

Vasoactive-Inotropic Score may be a valid measure to quantify cardiovascular support in preterm infants needing hemodynamic support. Maximum VIS ≥20 within 48 h of treatment initiation may identify patients at high risk of adverse outcomes.

Clinical burden associated with therapies for cardio-pulmonary critical decompensation in preterm neonates across Canadian neonatal intensive care units

The aim of this retrospective cohort study was to study the clinical burden associated with cardio-pulmonary critical decompensations (CPCDs) in preterm neonates and factors associated with mortality. Through the Canadian Neonatal Network (30 tertiary NICUs, 2010-2017), we identified infants < 32-week gestational age with CPCDs, defined by "significant exposure" to cardiotropes and/or inhaled nitric oxide (iNO): (1) either therapy for ≥ 3 consecutive days, (2) both for ≥ 2 consecutive days, or (3) any exposure within 2 days of death. Early CPCDs (≤ 3 days of age) and late CPCDs (> 3 days) were examined separately. Outcomes included CPCD-incidence, mortality, and inter-site variability using standardized ratios (observed/adjusted expected rate) and network funnel plots. Mixed-effects analysis was used to quantify unit-level variability in mortality. Overall, 10% of admissions experienced CPCDs (n = 2915). Late CPCDs decreased by ~ 5%/year, while early CPCDs were unchanged during the study period. Incidence and CPCD-associated mortality varied between sites, for both early (0.6-7.5% and 0-100%, respectively) and late CPCDs (2.5-15% and 14-83%, respectively), all p < 0.01. Units' late-CPCD incidence and mortality demonstrated an inverse relationship (slope =  -2.5, p < 0.01). Mixed-effects analysis demonstrated clustering effect, with 6.4% and 8.6% of variability in mortality after early and late CPCDs respectively being site-related, unexplained by available patient-level characteristics or unit volume. Mortality was higher with combined exposure than with only-cardiotropes or only-iNO (41.3%, 24.8%, 21.5%, respectively; p < 0.01).

CONCLUSIONS

Clustering effects exist in CPCD-associated mortality among Canadian NICUs, with higher incidence units showing lower mortality. These data may aid network-level benchmarking, patient-level risk stratification, parental counseling, and further research and quality improvement work.

WHAT IS KNOWN

• Preterm neonates remain at high risk of acute and chronic complications; the most critically unwell require therapies such as cardiotropic drugs and inhaled nitric oxide. • Infants requiring these therapies are known to be at high risk for adverse neonatal outcomes and for mortality.

WHAT IS NEW

• This study helps illuminate the national burden of acute cardio-pulmonary critical decompensation (CPCD), defined as the need for cardiotropic drugs or inhaled nitric oxide, and highlights the high risk of morbidity and mortality associated with this disease state. • Significant nationwide variability exists in both CPCD incidence and associated mortality; a clustering effect was observed with higher incidence sites showing lower CPCD-associated mortality.

COVID-19 pandemic and population-level pregnancy and neonatal outcomes in general population: A living systematic review and meta-analysis (Update#2: November 20, 2021)

INTRODUCTION

Conflicting reports of increases and decreases in rates of preterm birth (PTB) and stillbirth in the general population during the coronavirus disease 2019 (COVID-19) pandemic have surfaced. The objective of our study was to conduct a living systematic review and meta-analyses of studies reporting pregnancy and neonatal outcomes by comparing the pandemic and pre-pandemic periods.

MATERIAL AND METHODS

We searched the PubMed and Embase databases and reference lists of articles published up until November 20, 2021, and included English language studies that compared outcomes between the COVID-19 pandemic time period with pre-pandemic time periods. Risk of bias was assessed using the Newcastle-Ottawa scale. We conducted random-effects meta-analysis using the inverse variance method.

RESULTS

Fifty-two studies with low-to-moderate risk of bias, reporting on 2 372 521 pregnancies during the pandemic period and 28 518 300 pregnancies during the pre-pandemic period, were included. There was significant reduction in unadjusted estimates of PTB (43 studies, unadjusted odds ratio [uaOR] 0.95, 95% CI 0.93-0.98), but not in adjusted estimates (five studies, adjusted OR [aOR] 0.94, 95% CI 0.74-1.19). This reduction was noted in studies from single centers/health areas (29 studies, uaOR 0.90, 95% CI 0.85-0.94) but not in regional/national studies (14 studies, uaOR 0.99, 95% CI 0.99-1.01). There was reduction in spontaneous PTB (nine studies, uaOR 0.91, 95% CI 0.88-0.94) but not in induced PTB (eight studies, uaOR 0.90, 95% CI 0.79-1.01). There was no difference in the odds of stillbirth between the pandemic and pre-pandemic time periods (32 studies, uaOR 1.07, 95% CI 0.97-1.18 and three studies, aOR 1.18, 95% CI 0.86-1.63). There was an increase in mean birthweight during the pandemic period compared with the pre-pandemic period (nine studies, mean difference 21 g, 95% CI 13-30 g). The odds of maternal mortality were increased (five studies, uaOR 1.15, 95% CI 1.05-1.26); however, only unadjusted estimates were available, and the result was mostly influenced by one study from Mexico. There was significant publication bias for the outcome of PTB.

CONCLUSIONS

The COVID-19 pandemic may be associated with a reduction in PTB; however, referral bias cannot be excluded. There was no statistically significant difference in stillbirths between pandemic and pre-pandemic periods.

Hemodynamic dysfunction in neonatal sepsis

Cardiovascular disturbances are a frequent occurrence in neonatal sepsis. Preterm and term infants are particularly vulnerable due to the unique features of their cardiovascular function and reserve, compared to older children and adults. The clinical manifestations of neonatal sepsis are a product of the variable inflammatory pathways involved (warm vs. cold shock physiology), developmental state of the cardiovascular system, and hormonal responses. Targeted neonatal echocardiography has played an important role in advancing our knowledge, may help delineate specific hemodynamic phenotypes in real-time, and supports an individualized physiology-based management of sepsis-associated cardiovascular dysfunction. IMPACT: Cardiovascular dysfunction is a common sequela of sepsis. This review aims to highlight the pathophysiological mechanisms involved in hemodynamic disturbance in neonatal sepsis, provide insights from targeted neonatal echocardiography-based clinical studies, and suggest its potential incorporation in day-to-day management.

Factors associated with antibiotic administration delay among preterm infants with late-onset bloodstream infection

Early antibiotic administration is an important modifiable factor in reducing mortality from late-onset bloodstream infections in preterm infants. In a cohort study including 142 infants with non-coagulase negative staphylococcus bloodstream infection at two tertiary neonatal intensive care units, we identified typical practice-related factors that may be targeted to prevent delays in antibiotic administration. Collection of cerebrospinal fluid or urine sample before administering antibiotics, a longer time taken to site a peripheral intravenous catheter among those without pre-existing access, and a longer time taken to administer fluid boluses were associated with a longer than median time to antibiotic administration.

Coronavirus disease 2019 pandemic and pregnancy and neonatal outcomes in general population: A living systematic review and meta-analysis (updated Aug 14, 2021)

Introduction

Conflicting reports of increases and decreases in rates of preterm birth (PTB) and stillbirth in the general population during the coronavirus disease 2019 (COVID‐19) pandemic have surfaced. The objective of our study was to conduct a living systematic review and meta‐analyses of studies reporting pregnancy and neonatal outcomes by comparing the pandemic and pre‐pandemic periods.

Material and methods

We searched PubMed and Embase databases, reference lists of articles published up until August 14, 2021 and included English language studies that compared outcomes between the COVID‐19 pandemic time period and the pre‐pandemic time periods. Risk of bias was assessed using the Newcastle–Ottawa scale. We conducted random‐effects meta‐analysis using the inverse variance method.

Results

Forty‐five studies with low‐to‐moderate risk of bias, reporting on 1 843 665 pregnancies during the pandemic period and 23 564 552 pregnancies during the pre‐pandemic period, were included. There was significant reduction in unadjusted estimates of PTB (35 studies, unadjusted odds ratio [uaOR] 0.95, 95% CI 0.92–0.98), but not in adjusted estimates (six studies, adjusted OR [aOR] 0.95, 95% CI 0.80–1.13). This reduction was noted in studies from single centers/health areas (25 studies, uaOR 0.90, 95% CI 0.86–0.96) but not in regional/national studies (10 studies, uaOR 0.99, 95% CI 0.95–1.02). There was reduction in spontaneous PTB (six studies, uaOR 0.89, 95% CI 0.81–0.96) and induced PTB (five studies, uaOR 0.89, 95% CI 0.81–0.97). There was no difference in the odds of stillbirth between the pandemic and pre‐pandemic time periods (24 studies, uaOR 1.11, 95% CI 0.97–1.26 and four studies, aOR 1.06, 95% CI 0.81–1.38). There was an increase in mean birthweight during the pandemic period compared with the pre‐pandemic period (six studies, mean difference 17 g, 95% CI 7–28 g). The odds of maternal mortality were increased (four studies, uaOR 1.15, 95% CI 1.05–1.26); however, only unadjusted estimates were available and the result was mostly influenced by one study from Mexico. There was significant publication bias for the outcome of PTB.

Conclusions

The COVID‐19 pandemic may be associated with a reduction in PTB; however, referral bias cannot be excluded. There was no statistically significant difference in stillbirth between pandemic and pre‐pandemic periods.

Bloodstream Infections in Preterm Neonates and Mortality-Associated Risk Factors

OBJECTIVE

To investigate the association of early (±4 hours after onset of bloodstream infection) clinical and laboratory variables with episode-related mortality (<7 days).

STUDY DESIGN

This 2-site retrospective study included 142 neonates born at <35 weeks of gestational age with positive blood/cerebrospinal fluid (CSF) culture at >72 hours of age from organisms other than coagulase-negative Staphylococcus. Early variables were compared between those with bloodstream infection-related mortality and survivors. Multivariable analysis was conducted for the primary outcome, and the area under the curve (AUC) was estimated for relevant variables.

RESULTS

The neonates who died were of lower gestational age at disease onset. After adjusting for relevant variables, lowest mean blood pressure (MBP) (aOR, 0.10; 95% CI, 1.02-1.19) and highest base deficit (aOR, 1.18; 95% CI, 1.06-1.32) were independently associated with mortality. The AUC was 0.87 (95% CI, 0.78-0.96) for base deficit, increasing to 0.91 (95% CI, 0.83-0.99) with the addition of MBP.

CONCLUSION

Low MBP and high base deficit within ±4 hours of bloodstream infection onset identify preterm neonates at risk of mortality.

COVID-19 pandemic and population-level pregnancy and neonatal outcomes: a living systematic review and meta-analysis

Introduction

Conflicting reports of increases and decreases in rates of preterm birth (PTB) and stillbirth in the general population during the COVID‐19 pandemic have surfaced. The objective of our study was to conduct a living systematic review and meta‐analyses of studies reporting pregnancy and neonatal outcomes by comparing the pandemic and pre‐pandemic periods.

Material and methods

We searched PubMed and Embase databases, reference lists of articles published up until 14 May 2021 and included English language studies that compared outcomes between the COVID‐19 pandemic time period and pre‐pandemic time periods. Risk of bias was assessed using the Newcastle–Ottawa scale. We conducted random‐effects meta‐analysis using the inverse variance method.

Results

Thirty‐seven studies with low‐to‐moderate risk of bias, reporting on 1 677 858 pregnancies during the pandemic period and 21 028 650 pregnancies during the pre‐pandemic period, were included. There was a significant reduction in unadjusted estimates of PTB (28 studies, unadjusted odds ratio [uaOR] 0.94, 95% confidence [CI] 0.91–0.98) but not in adjusted estimates (six studies, adjusted OR [aOR] 0.95, 95% CI 0.80–1.13). The reduction was noted in studies from single centers/health areas (uaOR 0.90, 95% CI 0.86–0.94) but not in regional/national studies (uaOR 0.99, 95% CI 0.95–1.03). There was reduction in spontaneous PTB (five studies, uaOR 0.89, 95% CI 0.82–0.98) and induced PTB (four studies, uaOR 0.90, 95% CI 0.81–1.00). There was no reduction in PTB when stratified by gestational age <34, <32 or <28 weeks. There was no difference in stillbirths between the pandemic and pre‐pandemic time periods (21 studies, uaOR 1.08, 95% CI 0.94–1.23; four studies, aOR 1.06, 95% CI 0.81–1.38). There was an increase in birthweight (six studies, mean difference 17 g, 95% CI 7–28 g) during the pandemic period. There was an increase in maternal mortality (four studies, uaOR 1.15, 95% CI 1.05–1.26), which was mostly influenced by one study from Mexico. There was significant publication bias for the outcome of PTB.

Conclusions

The COVID‐19 pandemic time period may be associated with a reduction in PTB; however, referral bias cannot be excluded. There was no difference in stillbirth between the pandemic and pre‐pandemic period.

Multicentre prospective observational study exploring the predictive value of functional echocardiographic indices for early identification of preterm neonates at risk of developing chronic pulmonary hypertension secondary to chronic neonatal lung disease

INTRODUCTION

Although chronic pulmonary hypertension (cPH) secondary to chronic neonatal lung disease is associated with increased mortality and respiratory and neurodevelopmental morbidities, late diagnosis (typically ≥36 weeks postmenstrual age, PMA) and the use of qualitative echocardiographic diagnostic criterion (flat interventricular septum in systole) remain significant limitations in clinical care. Our objective in this study is to evaluate the utility of relevant quantitative echocardiographic indices to identify cPH in preterm neonates, early in postnatal course and to develop a diagnostic test based on the best combination of markers.

METHODS AND ANALYSIS

In this ongoing international prospective multicentre observational diagnostic accuracy study, we aim to recruit 350 neonates born <27 weeks PMA and/or birth weight <1000 g and perform echocardiograms in the third week of age and at 32 weeks PMA (early diagnostic assessments, EDA) in addition to the standard diagnostic assessment (SDA) for cPH at 36 weeks PMA. Predefined echocardiographic markers under investigation will be measured at each EDA and examined to create a scoring system to identify neonates who subsequently meet the primary outcome of cPH/death at SDA. Diagnostic test characteristics will be defined for each EDA. Pulmonary artery acceleration time and tricuspid annular plane systolic excursion are the primary markers of interest.

ETHICS AND DISSEMINATION

Ethics approval has been received by the Mount Sinai Hospital Research Ethics Board (REB) (#16-0111-E), Sunnybrook Health Sciences Centre REB (#228-2016), NHS Health Research Authority (IRAS 266498), University of Iowa Human Subjects Office/Institutional Review Board (201903736), Rotunda Hospital Research and Ethics Committee (REC-2019-008), and UBC Children's and Women's REB (H19-02738), and is under review at Boston Children's Hospital Institutional Review Board. Study results will be disseminated to participating families in lay format, presented to the scientific community at paediatric and critical care conferences and published in relevant peer-reviewed journals.

TRAIL REGISTRATION NUMBER

NCT04402645.

Merits and perils of targeted neonatal echocardiography-based hemodynamic research: a position statement

In the neonatal setting, point-of-care ultrasound is increasingly being used to help clinicians with the evaluation of heart function. Practices in neonatology, particularly with regard to acute and chronic hemodynamic managements, were traditionally more driven on dogma and predefined thresholds and not always supported by demonstrable physiology. For the first time, targeted neonatal echocardiography (TNE) provided neonatal intensivists with a bedside tool that made real-time assessment of neonatal hemodynamics status feasible in even the tiniest of babies. This opened the door towards more targeted physiological driven practices, allowing us to test historical approaches to clinical problems in a more precise way. Despite the standardization of TNE training and the creation of a formalized curriculum, little attention has been paid to the establishment of an empirical framework to adjudicate scientific investigation. In this position statement, we reflect on the evolution of TNE in Canadian neonatal intensive care units, appraise its strengths and limitations, and suggest guiding principles for clinicians and researchers to consider as they take this field forward.

Conformational stability studies of the pleckstrin DEP domain: definition of the domain boundaries

Pleckstrin is the major substrate of protein kinase C in platelets. It contains at its N- and C-termini two pleckstrin homology (PH) domains which have been proposed to mediate protein-protein and protein-lipid interactions. A new module, called DEP, has recently been identified by sequence analysis in the central region of pleckstrin. In order to study this module, several recombinant polypeptides corresponding to the DEP module and N- and C-termini extended forms have been expressed. Using circular dichroism (CD) and nuclear magnetic resonance (NMR) techniques, the domain boundaries have been determined that yield a soluble and folded pleckstrin DEP domain. This comprises 93 amino acids with an alpha/beta fold in agreement with secondary structure predictions. Stability studies indicate that the regions surrounding the DEP domain do not contribute to its stability suggesting that the phosphorylation sites at S113, T114 and S117 are in an unstructured region. Identification of the regions of pleckstrin that are folded shall facilitate determination of its structure and function.

Structure of the dsRNA binding domain of E. coli RNase III

The double-stranded RNA binding domain (dsRBD) is a approximately 70 residue motif found in a variety of modular proteins exhibiting diverse functions, yet always in association with dsRNA. We report here the structure of the dsRBD from RNase III, an enzyme present in most, perhaps all, living cells. It is involved in processing transcripts, such as rRNA precursors, by cleavage at short hairpin sequences. The RNase III protein consists of two modules, a approximately 150 residue N-terminal catalytic domain and a approximately 70 residue C-terminal recognition module, homologous with other dsRBDs. The structure of the dsRBD expressed in Escherichia coli has been investigated by homonuclear NMR techniques and solved with the aid of a novel calculation strategy. It was found to have an alpha-beta-beta-beta-alpha topology in which a three-stranded anti-parallel beta-sheet packs on one side against the two helices. Examination of 44 aligned dsRBD sequences reveals several conserved, positively charged residues. These residues map to the N-terminus of the second helix and a nearby loop, leading to a model for the possible contacts between the domain and dsRNA.

Concerted activities of the RNA recognition and the glycine-rich C-terminal domains of nucleolin are required for efficient complex formation with pre-ribosomal RNA

Nucleolin is an abundant nucleolar protein which is involved in the early stages of ribosome assembly. The central 40-kDa domain of nucleolin comprises four RNA recognition motifs (RRM) which are presumed to be involved in specific interactions with pre-rRNA. In order to examine in detail the role of this central domain and the contribution of the N-terminal and C-terminal domains of nucleolin to RNA binding, we have used an Escherichia coli expression system to synthezise polypeptides corresponding to various combinations of the three domains and their subdomains. By means of an in-vitro binding assay and a synthetic RNA corresponding to a specific recognition site in pre-rRNA we have been able to demonstrate conclusively that the central 40-kDa domain is indeed responsible for the specificity of RNA recognition and that the N-terminal domain can be removed without affecting RNA binding. Most interestingly, it appears that the C-terminal 10-kDa domain, which is rich in glycine and arginine residues, is essential for efficient binding of nucleolin to RNA, but does not itself contribute to the specificity of the interaction. Circular dichroic spectroscopic probing of the RNA component shows that the C-terminal domain significantly modifies the RNA-binding properties of the central RRM core. Finally, infrared spectroscopic studies reveal that the central 40-kDa domain is structured in alpha helices and beta sheets and that the interaction with the specific pre-rRNA site induces subtle changes in the beta sheet conformation.

Synergistic effect of histone H1 and nucleolin on chromatin condensation in mitosis: role of a phosphorylated heteromer

Repeated motifs, rich in basic residues, are characteristic of both the N-terminal domain of the nucleolus-specific protein, nucleolin, and the second half of the C-terminal domain of histone H1. These repeats are also the target for phosphorylation by the mitosis-specific p34cdc2 kinase. We have previously shown that synthetic peptides [(KTPKKAKKP)2 for histone H1 and (ATPAKKAA)2 for nucleolin] corresponding to these two repeated motifs are able to act in synergy to induce DNA hypercondensation (Erard et al., 1990). In order to determine the molecular basis of this synergistic interaction, we have studied the condensation of the homopolymer poly(dA).poly(dT) in the presence of the two synthetic peptides. Circular dichroism has been used to monitor the psi (+)-type condensation and has revealed that phosphorylation enhances the synergistic effect of the two peptides. Analysis of different combinations of the two peptides suggests that there is a direct interaction between them which is stabilized by phosphorylation. Furthermore, there is a striking correlation between the degree of homopolymer condensation and the stability of the heteromeric complex. Phosphorylation takes place on the threonine residues on the repeat motifs within a region which is likely to adopt a beta-turn structure. Circular dichroism and infrared spectroscopy provide evidence that phosphorylation stabilizes the beta-turn structure of both peptides, and computer modeling shows that this may be due to steric hindrance imposed by the phosphate group. We suggest that phosphorylated nucleolin and histone H1 interact through their homologous domain structured in beta-spirals in order to condense certain forms of DNA during mitosis.

[Incidence of amplification of the C-erb B2/Her-2/neu gene in human breast cancer]

Activation of cellular proto-oncogenes can be detected in several human cancers. In the current study, alterations of C-erb B2 gene in primary human breast cancers were investigated. It was found to be amplified from 2 to 30 fold in 25% of the tumors. Correlations of gene amplification with several disease parameters was evaluated.

Déplacements homolytiques intramoléculaires. 4. Thermolyse du perpentène-4 oate de tert-butyle dans les acides et leurs derivés: préparation de γ-butyrolactones substituées en 4 par un groupe comportant une fonction ester, acide ou nitrile

The thermolysis of tert-butylperpent-4-enoate in various solvents ZH (carboxylic acids, anhydrides, methyl esters, nitriles) led to γ-butyrolactones 4-substituted by the group ZCH2 with good yields. The acidic treatment of the lactones 4 and 6 derived from non-functionalized alkanoic acids and methyl esters gave respectively the isomerized lactones 5 and 7, increasing the synthetic interest of the studied homolytic reaction.

Type IV hyperlipoproteinemia in patients with algodystrophy

The present work studies lipid metabolism in patients with algodystrophy (AD). A correct positive correlation (r = 0.75) between the triglyceride levels and low density lipoprotein (LDL)/very low density lipoprotein (VLDL) ratio and the VLDL increase observed by gel disk electrophoresis confirm that a type IV hyperlipoproteinemia is associated with AD. In contrast, the degree of high density lipoprotein (HDL) saturation in cholesterol (HDL-cholesterol/HDL-phospholipids) and the classical atherogenous index (cholesterol/HDL-cholesterol) were not modified. The decrease of plasma post-heparin lipolytic activities (PHLA) was not significant but further studies should be performed to correlate PHLA with a reduced activity of the adipose tissue lipoprotein lipase.

Déplacements homolytiques intramoléculaires. 2. Décomposition du perpentène-4 oate de tert-butyle dans les éthers

The thermolysis of tert-butyl perpent-4-enoate 1 in THF led to several compounds; the main product, 5-(2-tetrahydrofuryl)-4-pentanolide (yield 42%) comes from an induced decomposition of the perester occurring with the addition of 2-tetrahydrofuryl radical to the double bond. A similar reaction was performed at a lower temperature, using butyl perdicarbonate as initiator, but did not define the mechanism (concerted or two-step). The thermolysis of 1 in ethers (THP, oxepane, 1,4-dioxane, dipropyl ether) appears to be a useful synthetic tool: several new γ-lactones have been obtained in this way.

[Algodystrophy and metabolic abnormalities]

The French Society of Rheumatology national study of reflex dystrophy revealed a serum glucose greater than 1.20 g/l in 9.09 p. cent of cases, a serum uric acid greater than 70 mg/l in 25 p. cent of men and greater than 60 mg/l in 14 p. cent of women. Serum cholesterol was normal in males, but higher than the mean + 2 sigma in 23 p. cent of females. Serum triglycerides were higher than m + 2 sigma in 55 p. cent of men and 56 p. cent of women. From a group of 80 patients, 54 (67.5 p. cent) had at least one of the three metabolic abnormalities and 49 (61.25 p. cent) were hypertriglyceridaemic. This hypertriglyceridaemia is the most frequent abnormality found. When hyperglycaemia or hyperuricaemia are present it is almost always in association with hypertriglyceridaemia. Hypertriglyceridaemia is more common in algoneurodystrophy of the lower limbs (54/78, 69 p. cent) than in algoneurodystrophy of the upper limbs (5/22, 22.7 p. cent). Algoneurodystrophy is more often primary, when it occurs in the lower limbs and post-traumatic when it occurs in the upper limbs. A prospective study comparing several parameters of lipid metabolism in 24 patients with algoneurodystrophy and 15 matched controls showed a significant drop in the HDL Chol/HDL P1 ratio and in the DHL - HDL Chol/TG ratio in patients with algoneurodystrophy. Serum insulin was comparable in the 2 groups. Lecithin cholesterol acyl transferase (LCAT), SGOT, SGPT and GGT were normal. The essential role of hypertriglyceridaemia in the genesis of the characteristic bony lesions of algoneurodystrophy is discussed.

[Algodystrophy and metabolic anomalies]

The French Society of Rheumatology national study of reflex dystrophy revealed a serum glucose greater than 1.20 g/l in 9.09 p. cent of case, a serum uric acid greater than 70 mg/l in 25 p. cent of men and greater than 60 mg/l in 14 p. cent of women. Serum cholesterol was normal in male cases, but higher than the mean + 2 sigma in 23 p. cent of female cases. Serum triglycerides was higher than m + 2 sigma in 55 p. cent of men and 56 p. cent of women. From a group of 80 patients, 54 (67.5 p. cent) had at least one of the three metabolic abnormalities and 49 (61.25 p. cent) were hypertriglyceridaemic. This hypertriglyceridaemia is the most frequent abnormality found. When hyperglycaemia or hyperuricaemia are present it is almost always in association with hypertriglyceridaemia. Hypertriglyceridaemia is more common in algoneurodystrophy of the lower limbs (54/78, 69 p. cent) than in algoneurodystrophy of the upper limbs (5/22, 22.7 p. cent). Algoneurodystrophy is more often primary, when it occurs in the lower limbs and post-traumatic when it occurs in the upper limbs. A prospective study comparing several parameters of lipid metabolism between 24 patients with algoneurodystrophy and 15 matched controls showed a significant drop in the HDL Chol/HDL P1 ratio and in the DHL--HDL Chol/TG ratio in patients with algoneurodystrophy. Serum insulin was comparable in the 2 groups. Lecithin cholesterol acyl transferase (LCAT), SGOT, SGPT and GGT were normal. The essential role of hypertriglyceridaemia in the genesis of the characteristic bony lesions of algoneurodystrophy is discussed.