Patterns of isozyme variation in relation to population size, isolation, and phytogeographic history in royal catchfly

The distribution of genetic variation within and among plant populations is influenced by both contemporary and historical factors. I used isozyme analysis of band phenotypes to examine genetic structure in the rare prairie forb Silene regia. Relationships between current-day population size, isolation, and phenotypic variation were assessed for 18 populations in two regions with differing postglacial history. Western populations from unglaciated southern Missouri and Arkansas were more genetically diverse based on the Shannon-Weaver index (H) and a polymorphic index than were more eastern populations. These differences may be due to loss of variation with repeated founding of new populations in previously glaciated sites in Indiana and Ohio. Within the western region, population size was not significantly correlated with genetic variation. In the east, size was correlated with Shannon-Weaver diversity. There was no relationship between variation and isolation in either region, but eastern populations were slightly more differentiated. Greater among-population differentiation and the demonstrated connection between population size and variation in the eastern sites may reflect lower levels of interpopulation gene flow in the fragmented remnant prairies of Indiana and Ohio

Ventilation Strategies During Extracorporeal Membrane Oxygenation for Neonatal Respiratory Failure: Current Approaches Among Level IV Neonatal ICUs

To describe ventilation strategies used during extracorporeal membrane oxygenation (ECMO) for neonatal respiratory failure among level IV neonatal ICUs (NICUs). Design: Cross-sectional electronic survey. Setting: Email-based Research Electronic Data Capture survey. Patients: Neonates undergoing ECMO for respiratory failure at level IV NICUs. Interventions: A 40-question survey was sent to site sponsors of regional referral neonatal ECMO centers participating in the Children\u27s Hospitals Neonatal Consortium. Reminder emails were sent at 2- and 4-week intervals. Measurements and main results: Twenty ECMO centers responded to the survey. Most primarily use venoarterial ECMO (65%); this percentage is higher (90%) for congenital diaphragmatic hernia. Sixty-five percent reported following protocol-based guidelines, with neonatologists primarily responsible for ventilator management (80%). The primary mode of ventilation was pressure control (90%), with synchronized intermittent mechanical ventilation (SIMV) comprising 80%. Common settings included peak inspiratory pressure (PIP) of 16-20 cm H2O (55%), positive end-expiratory pressure (PEEP) of 9-10 cm H2O (40%), I-time 0.5 seconds (55%), rate of 10-15 (60%), and Fio2 22-30% (65%). A minority of sites use high-frequency ventilation (HFV) as the primary mode (5%). During ECMO, 55% of sites target some degree of lung aeration to avoid complete atelectasis. Fifty-five percent discontinue inhaled nitric oxide (iNO) during ECMO, while 60% use iNO when trialing off ECMO. Nonventilator practices to facilitate decannulation include bronchoscopy (50%), exogenous surfactant (25%), and noninhaled pulmonary vasodilators (50%). Common ventilator thresholds for decannulation include PEEP of 6-7 (45%), PIP of 21-25 (55%), and tidal volume 5-5.9 mL/kg (50%). Conclusions: The majority of level IV NICUs follow internal protocols for ventilator management during neonatal respiratory ECMO, and neonatologists primarily direct management in the NICU. While most centers use pressure-controlled SIMV, there is considerable variability in the range of settings used, with few centers using HFV primarily. Future studies should focus on identifying respiratory management practices that improve outcomes for neonatal ECMO patients

Effect of Depth and Duration of Cooling on Death or Disability at Age 18 Months Among Neonates With Hypoxic-Ischemic Encephalopathy: A Randomized Clinical Trial

Importance Hypothermia for 72 hours at 33.5°C for neonatal hypoxic-ischemic encephalopathy reduces death or disability, but rates continue to be high. Objective To determine if cooling for 120 hours or to a temperature of 32.0°C reduces death or disability at age 18 months in infants with hypoxic-ischemic encephalopathy. Design, Setting, and Participants Randomized 2 × 2 factorial clinical trial in neonates (≥36 weeks’ gestation) with hypoxic-ischemic encephalopathy at 18 US centers in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network between October 2010 and January 2016. Interventions A total of 364 neonates were randomly assigned to 4 hypothermia groups: 33.5°C for 72 hours (n = 95), 32.0°C for 72 hours (n = 90), 33.5°C for 120 hours (n = 96), or 32.0°C for 120 hours (n = 83). Main Outcomes and Measures The primary outcome was death or moderate or severe disability at 18 to 22 months of age adjusted for center and level of encephalopathy. Severe disability included any of Bayley Scales of Infant Development III cognitive score less than 70, Gross Motor Function Classification System (GMFCS) level of 3 to 5, or blindness or hearing loss despite amplification. Moderate disability was defined as a cognitive score of 70 to 84 and either GMFCS level 2, active seizures, or hearing with amplification. Results The trial was stopped for safety and futility in November 2013 after 364 of the planned 726 infants were enrolled. Among 347 infants (95%) with primary outcome data (mean age at follow-up, 20.7 [SD, 3.5] months; 42% female), death or disability occurred in 56 of 176 (31.8%) cooled for 72 hours and 54 of 171 (31.6%) cooled for 120 hours (adjusted risk ratio, 0.92 [95% CI, 0.68-1.25]; adjusted absolute risk difference, −1.0% [95% CI, −10.2% to 8.1%]) and in 59 of 185 (31.9%) cooled to 33.5°C and 51 of 162 (31.5%) cooled to 32.0°C (adjusted risk ratio, 0.92 [95% CI, 0.68-1.26]; adjusted absolute risk difference, −3.1% [95% CI, −12.3% to 6.1%]). A significant interaction between longer and deeper cooling was observed (P = .048), with primary outcome rates of 29.3% at 33.5°C for 72 hours, 34.5% at 32.0°C for 72 hours, 34.4% at 33.5°C for 120 hours, and 28.2% at 32.0°C for 120 hours. Conclusions and Relevance Among term neonates with moderate or severe hypoxic-ischemic encephalopathy, cooling for longer than 72 hours, cooling to lower than 33.5°C, or both did not reduce death or moderate or severe disability at 18 months of age. However, the trial may be underpowered, and an interaction was found between longer and deeper cooling. These results support the current regimen of cooling for 72 hours at 33.5°C

Effect of Therapeutic Hypothermia Initiated After 6 Hours of Age on Death or Disability Among Newborns With Hypoxic-Ischemic Encephalopathy: A Randomized Clinical Trial

Importance: Hypothermia initiated at less than 6 hours after birth reduces death or disability for infants with hypoxic-ischemic encephalopathy at 36 weeks' or later gestation. To our knowledge, hypothermia trials have not been performed in infants presenting after 6 hours. Objective: To estimate the probability that hypothermia initiated at 6 to 24 hours after birth reduces the risk of death or disability at 18 months among infants with hypoxic-ischemic encephalopathy. Design, Setting, and Participants: A randomized clinical trial was conducted between April 2008 and June 2016 among infants at 36 weeks' or later gestation with moderate or severe hypoxic-ischemic encephalopathy enrolled at 6 to 24 hours after birth. Twenty-one US Neonatal Research Network centers participated. Bayesian analyses were prespecified given the anticipated limited sample size. Interventions: Targeted esophageal temperature was used in 168 infants. Eighty-three hypothermic infants were maintained at 33.5°C (acceptable range, 33°C-34°C) for 96 hours and then rewarmed. Eighty-five noncooled infants were maintained at 37.0°C (acceptable range, 36.5°C-37.3°C). Main Outcomes and Measures: The composite of death or disability (moderate or severe) at 18 to 22 months adjusted for level of encephalopathy and age at randomization. Results: Hypothermic and noncooled infants were term (mean [SD], 39 [2] and 39 [1] weeks' gestation, respectively), and 47 of 83 (57%) and 55 of 85 (65%) were male, respectively. Both groups were acidemic at birth, predominantly transferred to the treating center with moderate encephalopathy, and were randomized at a mean (SD) of 16 (5) and 15 (5) hours for hypothermic and noncooled groups, respectively. The primary outcome occurred in 19 of 78 hypothermic infants (24.4%) and 22 of 79 noncooled infants (27.9%) (absolute difference, 3.5%; 95% CI, -1% to 17%). Bayesian analysis using a neutral prior indicated a 76% posterior probability of reduced death or disability with hypothermia relative to the noncooled group (adjusted posterior risk ratio, 0.86; 95% credible interval, 0.58-1.29). The probability that death or disability in cooled infants was at least 1%, 2%, or 3% less than noncooled infants was 71%, 64%, and 56%, respectively. Conclusions and Relevance: Among term infants with hypoxic-ischemic encephalopathy, hypothermia initiated at 6 to 24 hours after birth compared with noncooling resulted in a 76% probability of any reduction in death or disability, and a 64% probability of at least 2% less death or disability at 18 to 22 months. Hypothermia initiated at 6 to 24 hours after birth may have benefit but there is uncertainty in its effectiveness

Effect of Depth and Duration of Cooling on Deaths in the NICU Among Neonates With Hypoxic Ischemic Encephalopathy: A Randomized Clinical Trial

Hypothermia at 33.5°C for 72 hours for neonatal hypoxic ischemic encephalopathy reduces death or disability to 44% to 55%; longer cooling and deeper cooling are neuroprotective in animal models

Limitations of Conventional Magnetic Resonance Imaging as a Predictor of Death or Disability Following Neonatal Hypoxic-Ischemic Encephalopathy in the Late Hypothermia Trial

Objective: To investigate if magnetic resonance imaging (MRI) is an accurate predictor for death or moderate-severe disability at 18-22 months of age among infants with neonatal encephalopathy in a trial of cooling initiated at 6-24 hours. Study design: Subgroup analysis of infants ≥36 weeks of gestation with moderate-severe neonatal encephalopathy randomized at 6-24 postnatal hours to hypothermia or usual care in a multicenter trial of late hypothermia. MRI scans were performed per each center's practice and interpreted by 2 central readers using the Eunice Kennedy Shriver National Institute of Child Health and Human Development injury score (6 levels, normal to hemispheric devastation). Neurodevelopmental outcomes were assessed at 18-22 months of age. Results: Of 168 enrollees, 128 had an interpretable MRI and were seen in follow-up (n = 119) or died (n = 9). MRI findings were predominantly acute injury and did not differ by cooling treatment. At 18-22 months, death or severe disability occurred in 20.3%. No infant had moderate disability. Agreement between central readers was moderate (weighted kappa 0.56, 95% CI 0.45-0.67). The adjusted odds of death or severe disability increased 3.7-fold (95% CI 1.8-7.9) for each increment of injury score. The area under the curve for severe MRI patterns to predict death or severe disability was 0.77 and the positive and negative predictive values were 36% and 100%, respectively. Conclusions: MRI injury scores were associated with neurodevelopmental outcome at 18-22 months among infants in the Late Hypothermia Trial. However, the results suggest caution when using qualitative interpretations of MRI images to provide prognostic information to families following perinatal hypoxia-ischemia

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Data from: Observational study of hemostatic dysfunction and bleeding in neonates with hypoxic-ischemic encephalopathy

Objective: Evaluate the relationship between initial haemostatic parameters and the frequency and severity of bleeding in neonates with hypoxic–ischaemic encephalopathy (HIE). Design: Retrospective observational cohort study. Setting: 2 academically affiliated level III neonatal intensive care units in Atlanta, Georgia. Participants: 98 neonates with moderate-to-severe HIE who underwent haemostatic testing within 12 hours of birth and were born from 1 January 2008 to 31 December 2013. Primary and secondary outcome measures: Initial haemostatic dysfunction was defined as one or more of the following: prothrombin time (PT) ≥18 s, platelet count <100×103/μL or fibrinogen <150 mg/dL. Bleeding assessed using the Neonatal Bleeding Assessment Tool and graded according to the WHO bleeding scale. The robust Poisson regression was used to evaluate the independent association between components of initial haemostatic dysfunction and bleeding. Results: Among the 98 neonates evaluated, the prevalence of initial haemostatic dysfunction was 69% (95% CI 59% to 78%). 27 neonates (28%; 95% CI 19% to 38%) had abnormal bleeding events and 56 (57%) received at least 1 blood product transfusion. 3 neonates died from bleeding complications. The most common products transfused were fresh-frozen plasma (71%), followed by packed red blood cells (24%) and platelets (21%). In multivariable analysis, fibrinogen <150 mg/dL (adjusted relative risk 2.41, 95% CI 1.09 to 5.36) and platelet count <100×103/μL (adjusted relative risk 2.59, 95% CI 1.30 to 5.16), but not initial PT, were associated with an increased risk of bleeding. The most severe bleeding occurred in neonates with a fibrinogen <150 mg/dL. Conclusions: Among neonates with moderate-to-severe HIE, haemostatic dysfunction is prevalent and associated with an increased risk of bleeding and high transfusion burden. Further studies are needed to determine the appropriate transfusion approaches in this population to prevent bleeding

Supplemental Material - Current practices for genetic testing in neonatal extracorporeal membrane oxygenation: Findings from a National survey

Supplemental Material for Current practices for genetic testing in neonatal extracorporeal membrane oxygenation: Findings from a National survey by KT Wild, Franscesca Miquel-Verges, Natalie E Rintoul, Robert DiGeronimo, Sarah Keene, Shannon E Hamrick, Burhan Mahmood, Rakesh Rao, Nicholas R Carr, on behalf of the Children’s Hospitals Neonatal Consortium (CHNC) in Perfusion</p