Rapture facilitates inexpensive and high-throughput parent-based tagging in salmonids

Accurate methods for tracking individuals are crucial to the success of fisheries and aquaculture management. Management of migratory salmonid populations, which are important for the health of many economies, ecosystems, and indigenous cultures, is particularly dependent on data gathered from tagged fish. However, the physical tagging methods currently used have many challenges including cost, variable marker retention, and information limited to tagged individuals. Genetic tracking methods combat many of the problems associated with physical tags, but have their own challenges including high cost, potentially difficult marker design, and incompatibility of markers across species. Here we show the feasibility of a new genotyping method for parent-based tagging (PBT), where individuals are tracked through the inherent genetic relationships with their parents. We found that Rapture sequencing, a combination of restriction-site associated DNA and capture sequencing, provides sufficient data for parentage assignment. Additionally, the same capture bait set, which targets specific restriction-site associated DNA loci, can be used for both Rainbow Trout Oncorhynchus mykiss and Chinook Salmon Oncorhynchus tshawytscha. We input 248 single nucleotide polymorphisms from 1,121 samples to parentage assignment software and compared parent-offspring relationships of the spawning pairs recorded in a hatchery. Interestingly, our results suggest sperm contamination during hatchery spawning occurred in the production of 14% of offspring, further confirming the need for genetic tagging in accurately tracking individuals. PBT with Rapture successfully assigned progeny to parents with a 98.86% accuracy with sufficient genetic data. Cost for this pilot study was approximately $3 USD per sample. As costs vary based on the number of markers used and individuals sequenced, we expect that when implemented at a large-scale, per sample costs could be further decreased. We conclude that Rapture PBT provides a cost-effective and accurate alternative to the physical coded wire tags, and other genetic-based methods.

On the Ecology and Distribution of Steelhead (Oncorhynchus mykiss) in California's Eel River

The preservation of life history and other phenotypic complexity is central to the resilience of Pacific salmon stocks. Steelhead (Oncorhynchus mykiss) express a diversity of life-history strategies such as the propensity to migrate (anadromy/residency) and the timing and state of maturation upon return to freshwater (run-timing), providing an opportunity to study adaptive phenotypic complexity. Historically, the Eel River supported upwards of 1 million salmon and steelhead, but the past century has seen dramatic declines of all salmonids in the watershed. Here we investigate life-history variation in Eel River steelhead by using Rapture sequencing, on thousands of individuals, to genotype the region diagnostic for run-timing (GREB1L) and the region strongly associated with residency/anadromy (OMY5) in the Eel River and other locations, as well as determine patterns of overall genetic differentiation. Our results provide insight into many conservation-related issues. For example, we found that distinct segregation between winter and summer-run steelhead correlated with flow-dependent barriers in major forks of the Eel, that summer-run steelhead inhabited the upper Eel prior to construction of an impassable dam, and that both life history and overall genetic diversity have been maintained in the resident trout population above; and we found no evidence of the summer-run allele in the South Fork Eel, indicating that summer run-timing cannot be expected to arise from standing genetic variation in this and other populations that lack the summer-run phenotype. The results presented in this study provide valuable information for designing future restoration and management strategies for O. mykiss in Northern California and beyond.

TNFα and Reactive Oxygen Signaling in Vascular Smooth Muscle Cells in Hypertension and Atherosclerosis

Hypertension and atherosclerosis, the predecessors of stroke and myocardial infarction, are chronic vascular inflammatory reactions. Tumor necrosis factor alpha (TNFα), the "master" proinflammatory cytokine, contributes to both the initiation and maintenance of vascular inflammation. TNFα induces reactive oxygen species (ROS) production which drives the redox reactions that constitute "ROS signaling." However, these ROS may also cause oxidative stress which contributes to vascular dysfunction. Mice lacking TNFα or its receptors are protected against both acute and chronic cardiovascular injury. Humans suffering from TNFα-driven inflammatory conditions such as rheumatoid arthritis and psoriasis are at increased cardiovascular risk. When treated with highly specific biologic agents that target TNFα signaling (Etanercept, etc.) they display marked reductions in that risk. The ability of TNFα to induce endothelial dysfunction, often the first step in a progression toward serious vasculopathy, is well recognized and has been reviewed elsewhere. However, TNFα also has profound effects on vascular smooth muscle cells (VSMCs) including a fundamental change from a contractile to a secretory phenotype. This "phenotypic switching" promotes proliferation and production of extracellular matrix proteins which are associated with medial hypertrophy. Additionally, it promotes lipid storage and enhanced motility, changes that support the contribution of VSMCs to neointima and atherosclerotic plaque formation. This review focuses on the role of TNFα in driving the inflammatory changes in VSMC biology that contribute to cardiovascular disease. Special attention is given to the mechanisms by which TNFα promotes ROS production at specific subcellular locations, and the contribution of these ROS to TNFα signaling.

Metabolomics Profiling of Critically Ill Coronavirus Disease 2019 Patients: Identification of Diagnostic and Prognostic Biomarkers

OBJECTIVES

Coronavirus disease 2019 continues to spread rapidly with high mortality. We performed metabolomics profiling of critically ill coronavirus disease 2019 patients to understand better the underlying pathologic processes and pathways, and to identify potential diagnostic/prognostic biomarkers.

DESIGN

Blood was collected at predetermined ICU days to measure the plasma concentrations of 162 metabolites using both direct injection-liquid chromatography-tandem mass spectrometry and proton nuclear magnetic resonance.

SETTING

Tertiary-care ICU and academic laboratory.

SUBJECTS

Patients admitted to the ICU suspected of being infected with severe acute respiratory syndrome coronavirus 2, using standardized hospital screening methodologies, had blood samples collected until either testing was confirmed negative on ICU day 3 (coronavirus disease 2019 negative) or until ICU day 10 if the patient tested positive (coronavirus disease 2019 positive).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Age- and sex-matched healthy controls and ICU patients that were either coronavirus disease 2019 positive or coronavirus disease 2019 negative were enrolled. Cohorts were well balanced with the exception that coronavirus disease 2019 positive patients suffered bilateral pneumonia more frequently than coronavirus disease 2019 negative patients. Mortality rate for coronavirus disease 2019 positive ICU patients was 40%. Feature selection identified the top-performing metabolites for identifying coronavirus disease 2019 positive patients from healthy control subjects and was dominated by increased kynurenine and decreased arginine, sarcosine, and lysophosphatidylcholines. Arginine/kynurenine ratio alone provided 100% classification accuracy between coronavirus disease 2019 positive patients and healthy control subjects (p = 0.0002). When comparing the metabolomes between coronavirus disease 2019 positive and coronavirus disease 2019 negative patients, kynurenine was the dominant metabolite and the arginine/kynurenine ratio provided 98% classification accuracy (p = 0.005). Feature selection identified creatinine as the top metabolite for predicting coronavirus disease 2019-associated mortality on both ICU days 1 and 3, and both creatinine and creatinine/arginine ratio accurately predicted coronavirus disease 2019-associated death with 100% accuracy (p = 0.01).

CONCLUSIONS

Metabolomics profiling with feature classification easily distinguished both healthy control subjects and coronavirus disease 2019 negative patients from coronavirus disease 2019 positive patients. Arginine/kynurenine ratio accurately identified coronavirus disease 2019 status, whereas creatinine/arginine ratio accurately predicted coronavirus disease 2019-associated death. Administration of tryptophan (kynurenine precursor), arginine, sarcosine, and/or lysophosphatidylcholines may be considered as potential adjunctive therapies.

Indirect genetic control of migration in a salmonid fish

Migration is a complex trait that often has genetic underpinnings. However, it is unclear if migratory behaviour itself is inherited (direct genetic control), or if the decision to migrate is instead the outcome of a set of physiological traits (indirect genetic control). For steelhead/rainbow trout (Oncorhynchus mykiss), migration is strongly linked to a large genomic region across their range. Here, we demonstrate a shared allelic basis between early life growth rate and migratory behaviour. Next, we demonstrate that early life growth differs among resident/migratory genotypes in wild juveniles several months prior to migration, with resident genotypes achieving a larger size in their first few months of life than migratory genotypes. We suggest that the genetic basis of migration is likely indirect and mediated by physiological traits such as growth rate. Evolutionary benefits of this indirect genetic mechanism likely include flexibility among individuals and persistence of life-history diversity within and among populations.

Inflammation Profiling of Critically Ill Coronavirus Disease 2019 Patients

OBJECTIVES

Coronavirus disease 2019 is caused by severe acute respiratory syndrome-coronavirus-2 infection to which there is no community immunity. Patients admitted to ICUs have high mortality, with only supportive therapies available. Our aim was to profile plasma inflammatory analytes to help understand the host response to coronavirus disease 2019.

DESIGN

Daily blood inflammation profiling with immunoassays.

SETTING

Tertiary care ICU and academic laboratory.

SUBJECTS

All patients admitted to the ICU suspected of being infected with severe acute respiratory syndrome-coronavirus-2, using standardized hospital screening methodologies, had daily blood samples collected until either testing was confirmed negative on ICU day 3 (coronavirus disease 2019 negative), or until ICU day 7 if the patient was positive (coronavirus disease 2019 positive).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Age- and sex-matched healthy controls and ICU patients that were either coronavirus disease 2019 positive or coronavirus disease 2019 negative were enrolled. Cohorts were well-balanced with the exception that coronavirus disease 2019 positive patients were more likely than coronavirus disease 2019 negative patients to suffer bilateral pneumonia. Mortality rate for coronavirus disease 2019 positive ICU patients was 40%. We measured 57 inflammatory analytes and then analyzed with both conventional statistics and machine learning. Twenty inflammatory analytes were different between coronavirus disease 2019 positive patients and healthy controls (p < 0.01). Compared with coronavirus disease 2019 negative patients, coronavirus disease 2019 positive patients had 17 elevated inflammatory analytes on one or more of their ICU days 1-3 (p < 0.01), with feature classification identifying the top six analytes between cohorts as tumor necrosis factor, granzyme B, heat shock protein 70, interleukin-18, interferon-gamma-inducible protein 10, and elastase 2. While tumor necrosis factor, granzyme B, heat shock protein 70, and interleukin-18 were elevated for all seven ICU days, interferon-gamma-inducible protein 10 transiently elevated on ICU days 2 and 3 and elastase 2 increased over ICU days 2-7. Inflammation profiling predicted coronavirus disease 2019 status with 98% accuracy, whereas elevated heat shock protein 70 was strongly associated with mortality.

CONCLUSIONS

While many inflammatory analytes were elevated in coronavirus disease 2019 positive ICU patients, relative to healthy controls, the top six analytes distinguishing coronavirus disease 2019 positive ICU patients from coronavirus disease 2019 negative ICU patients were tumor necrosis factor, granzyme B, heat shock protein 70, interleukin-18, interferon-gamma-inducible protein 10, and elastase 2.

Wildfire reveals transient changes to individual traits and population responses of a native bumble bee Bombus vosnesenskii

Fire-induced changes in the abundance and distribution of organisms, especially plants, can alter resource landscapes for mobile consumers driving bottom-up effects on their population sizes, morphologies and reproductive potential. We expect these impacts to be most striking for obligate visitors of plants, like bees and other pollinators, but these impacts can be difficult to interpret due to the limited information provided by forager counts in the absence of survival or fitness proxies. Increased bumble bee worker abundance is often coincident with the pulses of flowers that follow recent fire. However, it is unknown if observed postfire activity is due to underlying population growth or a stable pool of colonies recruiting more foragers to abundant resource patches. This distinction is necessary for determining the net impact of disturbance on bumble bees: are there population-wide responses or do just a few colonies reap the rewards? We estimated colony abundance before and after fire in burned and unburned areas using a genetic mark-recapture framework. We paired colony abundance estimates with measures of body size, counts of queens, and estimates of foraging and dispersal to assess changes in worker size, reproductive output, and landscape-scale movements. Higher floral abundance following fire not only increased forager abundance but also the number of colonies from which those foragers came. Importantly, despite a larger population size, we also observed increased mean worker size. Two years following fire, queen abundance was higher in both burned and unburned sites, potentially due to the dispersal of queens from burned into unburned areas. The effects of fire were transient; within two growing seasons, worker abundance was substantially reduced across the entire sampling area and body sizes were similar between burned and unburned sites. Our results reveal how disturbance can temporarily release populations from resource limitation, boosting the genetic diversity, body size, and reproductive output of populations. Given that the effects of fire on bumble bees acted indirectly through pulsed resource availability, it is likely our results are generalizable to other situations, such as habitat restorations, where resource density is enhanced within the landscape.

High-flow nasal cannula implementation has not reduced intubation rates for bronchiolitis in Canada

Background and Objective

Bronchiolitis is the most common reason for admission to hospital in the first year of life, with increasing hospitalization rates in Canada. Respiratory support with high-flow nasal cannula (HFNC) is being routinely used in paediatric centres, though the evidence of efficacy is continuing to be evaluated. We examined the impact of HFNC on intubation rates, hospital and paediatric critical care unit (PCCU) length of stay (LOS), and PCCU admission rates in paediatric tertiary centres in Canada.

Methods

We conducted a multicentre, interrupted time series analysis to examine intubation rates pre- to postimplementation of HFNC for bronchiolitis. Data were obtained from the Canadian Institute for Health Information database. Paediatric tertiary centres that introduced HFNC between 2009 and 2014 were included, and data were collected from April 2005 to March 2017.

Results

A total of 17,643 patients met inclusion criteria. There was no significant change in intubation rates after the introduction of HFNC. There was a significant increase in PCCU admission, with a decrease in the PCCU LOS following the introduction of HFNC. There was no significant change in average hospital LOS after HFNC was introduced.

Conclusions

This study adds to the evolving evidence showing that overall disease course is not modified by the use of HFNC. The initiation of HFNC in Canadian paediatric centres resulted in no significant change in intubation rates or average LOS in hospital, but had an increase in PCCU admissions. Careful monitoring of new technologies on their clinical impact as well as health care resource utilization is warranted.

Temporal dynamics of migration-linked genetic variation are driven by streamflows and riverscape permeability

Landscape permeability is often explored spatially, but may also vary temporally. Landscape permeability, including partial barriers, influences migratory animals that move across the landscape. Partial barriers are common in rivers where barrier passage varies with streamflow. We explore the influence of partial barriers on the spatial and temporal distribution of migration‐linked genotypes of Oncorhynchus mykiss, a salmonid fish with co‐occurring resident and migratory forms, in tributaries to the South Fork Eel River, California, USA, Elder and Fox Creeks. We genotyped >4,000 individuals using RAD‐capture and classified individuals as resident, heterozygous or migratory genotypes using life history‐associated loci. Across four years of study (2014–2017), the permeability of partial barriers varied across dry and wet years. In Elder Creek, the largest waterfall was passable for adults migrating up‐river 4–39 days each year. In this stream, the overall spatial pattern, with fewer migratory genotypes above the waterfall, remained true across dry and wet years (67%–76% of migratory alleles were downstream of the waterfall). We also observed a strong relationship between distance upstream and proportion of migratory alleles. In Fox Creek, the primary barrier is at the mouth, and we found that the migratory allele frequency varied with the annual timing of high flow events. In years when rain events occurred during the peak breeding season, migratory allele frequency was high (60%–68%), but otherwise it was low (30% in two years). We highlight that partial barriers and landscape permeability can be temporally dynamic, and this effect can be observed through changing genotype frequencies in migratory animals.

Use of complementary and alternative medicine in patients with inborn errors of metabolism: A single-center study

Background and Objectives

There is a paucity of information on the use of complementary and alternative medicine (CAM) in patients with inborn errors of metabolism (IEM). This study's objective was to evaluate the self-reported use and perceived effectiveness of CAM in adults and children with IEM.

Methods

Patients aged 0-70 years and caregivers seen at the London Health Sciences Centre Metabolic Clinic (London, Ontario, Canada) between July 2017 and August 2017 were recruited to complete a questionnaire regarding CAM use to help their IEM diagnosis and perceived effectiveness of these therapies. Survey responses were analyzed using descriptive statistics; age, sex, and education level associations among CAM users were tested using the Pearson χ ² test.

Results

Of 50 potential participants, 44 (88%) completed the questionnaire, including 21 adults (6 by caregivers) and 23 children (22 by caregivers). The most common IEM category was Aminoacidopathies and Small Molecule Disorders (50%). Twenty-seven (61%) participants reported CAM use to help their IEM diagnosis. The most common CAM therapies used were chiropractic manipulation, omega-3 fatty acids, probiotics, and aromatherapy/essential oils. Most CAM users and caregivers (74%) perceived their CAM therapies as effective overall. Among CAM users, 40% had not discussed CAM use with a health care professional (HCP). CAM use was similar when comparing age, sex and education level.

Conclusions

CAM is commonly used among patients with IEM. The safety and efficacy of CAM therapies for IEM should be further investigated. HCPs and patients should openly discuss CAM use in order to evaluate safety.

Publisher Correction: Sex-dependent dominance maintains migration supergene in rainbow trout

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Sex-dependent dominance maintains migration supergene in rainbow trout

Males and females often differ in their fitness optima for shared traits that have a shared genetic basis, leading to sexual conflict. Morphologically differentiated sex chromosomes can resolve this conflict and protect sexually antagonistic variation, but they accumulate deleterious mutations. However, how sexual conflict is resolved in species that lack differentiated sex chromosomes is largely unknown. Here we present a chromosome-anchored genome assembly for rainbow trout (Oncorhynchus mykiss) and characterize a 55-Mb double-inversion supergene that mediates sex-specific migratory tendency through sex-dependent dominance reversal, an alternative mechanism for resolving sexual conflict. The double inversion contains key photosensory, circadian rhythm, adiposity and sex-related genes and displays a latitudinal frequency cline, indicating environmentally dependent selection. Our results show sex-dependent dominance reversal across a large autosomal supergene, a mechanism for sexual conflict resolution capable of protecting sexually antagonistic variation while avoiding the homozygous lethality and deleterious mutations associated with typical heteromorphic sex chromosomes.

The Local South American Chicken Populations Are a Melting-Pot of Genomic Diversity

Chicken have a considerable impact in South American rural household economy as a source of animal protein (eggs and meat) and a major role in cultural traditions (e.g., cockfighting, religious ceremonies, folklore). A large number of phenotypes and its heterogeneity are due to the multitude of environments (from arid to tropical rain forest and high altitude) and agricultural systems (highly industrialized to subsistence agriculture). This heterogeneity also represents the successive introduction of domestic chicken into this continent, which some consider predating Columbus’ arrival to South America. In this study, we have used next-generation restriction site-associated DNA sequencing to scan for genome-wide variation across 145 South American chickens representing local populations from six countries of South America (Colombia, Brazil, Ecuador, Peru, Bolivia, and Chile). After quality control, the genotypes of 122,801 single nucleotide polymorphisms (SNPs) were used to assess the genomic diversity and interpopulation genetic relationship between those populations and their potential sources. The estimated population genetic diversity displayed that the gamefowl has the least diverse population (θπ = 0.86; θS = 0.70). This population is also the most divergent (F_ST = 0.11) among the South American populations. The allele-sharing analysis and the admixture analysis revealed that the current diversity displayed by these populations resulted from multiple admixture events with a strong influence of the modern commercial egg-layer chicken (ranging between 44% and 79%). It also revealed an unknown genetic component that is mostly present in the Easter Island population that is also present in local chicken populations from the South American Pacific fringe.

Remote Pediatric Critical Care Telephone Consultations: Quality and Outcomes

There are no studies describing the nature and quality of telephone consultations for critically ill children despite being an important part of pediatric intensive care. We described pediatric telephone consultations to a PICU in Ontario, Canada in 2011 and 2012. Of 203 consultations, 104 patients (51.2%) were admitted to the PICU; this was associated with weekend consultations ( p  = 0.005) and referral hospital location ( p  = 0.036). Frequency of interruptions was 1 in every 3.2 (2.0, 5.7) minutes and not associated with call content. Twenty-one percent of consults had limited discussion of vital signs. Our study described our center's remote critical care consultation program and outcomes.

Phylo-comparative analyses reveal the dual role of drift and selection in reproductive character displacement

When incipient species meet in secondary contact, natural selection can rapidly reduce costly reproductive interactions by directly targeting reproductive traits. This process, called reproductive character displacement (RCD), leaves a characteristic pattern of geographic variation where divergence of traits between species is greater in sympatry than allopatry. However, because other forces can also cause similar patterns, care must be given in separating pattern from process. Here we show how the phylo-comparative method together with genomic data can be used to evaluate evolutionary processes at the population level in closely related species. Using this framework, we test the role of RCD in speciation of two cricket species endemic to Anatolian mountains by quantifying patterns of character displacement, rates of evolution and adaptive divergence. Our results show differing patterns of character displacement between species for reproductive vs. non-reproductive characters and strong patterns of asymmetric divergence. We demonstrate diversification results from rapid divergence of reproductive traits towards multiple optima under the dual influence of strong drift and selection. These results present the first solid evidence for RCD in Anatolian mountains, quantify the amount of drift and selection necessary for RCD to lead to speciation, and demonstrate the utility of phylo-comparative methods for quantifying evolutionary parameters at the population level.

Labour Progression in Obese Women: Are Women With Increased Body Mass Index Having Unnecessary Cesarean Sections?

OBJECTIVE

This study sought to determine whether obese pregnant women undergo cesarean sections without an adequate trial of labour. This may affect future birth and pregnancy outcomes.

METHODS

A retrospective analysis was done on 526 parturients at Victoria Hospital in London, Ontario. Women were categorized according to parity and pre-pregnancy body mass index (BMI; normal weight, BMI 18.5-24.9 kg/m²; obese class II, BMI 35.0-39.9 kg/m²; obese class III, BMI ≥40 kg/m²). Patient charts and partograms were reviewed for labour progression (time at cervical dilation), demographics, and infant outcomes (Canadian Task Force Classification II-2).

RESULTS

Obese class II and III primiparous women required an additional 1.62 and 2.67 hours (P = 0.012), respectively, to reach a dilation of 10 cm compared with their normal weight counterparts; obese class II and III multiparous women required an additional 1.25 and 2.05 hours (P = 0.003), respectively. A higher BMI was associated with increased oxytocin use and infant birth weight in primiparous women. Obese women had less gestational weight gain and required more cervical examinations. Cesarean section rates were low for obese parturients (primiparous, 19%; multiparous, 0.8%) and not significantly different among BMI categories.

CONCLUSION

This study confirmed published results that labour progresses more slowly as maternal BMI increases. The study was performed in a centre with a specialized BMI pregnancy clinic; thus weight gain adherence, awareness of labour differences, and patient counselling may have contributed to low cesarean section rates. Obstetric care providers should consider differences in maternal BMI in labour progression before undertaking a potentially premature cesarean birth, especially in primiparous women.

Assessing the clinical utility of the diabetes eating problem survey-revised (DEPS-R) in adolescents with type 1 diabetes

OBJECTIVE

Eating disorders are prevalent among adolescents with type 1 diabetes (T1D). We examined the clinical utility of the Diabetes Eating Problem Survey-Revised (DEPS-R), a brief self-report questionnaire developed for patients with T1D, to identify at-risk adolescents. We aimed to determine whether a positive DEPS-R screen was predictive of a formal diagnosis of an eating disorder as per the DSM-V. In addition, we assessed whether other variables including psychosocial characteristics and diabetes conflict were associated with an abnormal DEPS-R screen.

METHODS

Cross-sectional study of 116 T1D adolescents aged 12-17 years. All participants completed the DEPS-R screening; both participants and parents completed a questionnaire addressing psychosocial characteristics/conflict around diabetes management. Clinical variables were obtained from participant charts. Differences were examined between positive and negative DEPS-R groups. Adolescents who screened positive were offered a referral to a specialized eating disorder team for further assessment.

RESULTS

From 116 participants (mean age ± SD = 14.6 years ± 1.56), 21% (24/116) scored positive for DEPS-R More females than males had abnormal DEPS-R (75% vs 25%, P = 0.001). Those with positive DEPS-R score had higher HbA1c% (mean = 9.3 ± 1.3 vs 8.3 ± 1.2, P = 0.001). Positive DEPS-R group had higher conflict score for diabetes management in both parents' and children's assessments (both ps < 0.001). In regression analysis, being female (OR males = 0.07, 95%CI: 0.010-0.46, P = 0.006), older (OR = 2.01, 95%CI: 1.16-3.48, P = 0.040) and > child-reported conflict (OR = 1.78, 95%CI: 1.02-3.11, P = 0.044) were predictors of an abnormal DEPS-R score.

CONCLUSION

The DEPS-R score is a useful clinical tool for identifying T1D adolescents at risk for disordered eating behaviour, but has a low positive predictive value (PPV) for identifying adolescents who meet diagnostic criteria for an eating disorder. Female gender, suboptimal diabetes control and increased conflict in diabetes management are associated with an abnormal DEPS-R score.

Impact of Early Postnatal Weight Gain on Retinopathy of Prematurity in Very Preterm Infants in Southwestern Ontario

PURPOSE

To examine the relationship between post-natal growth and development of retinopathy of prematurity (ROP) among preterm infants in southwestern Ontario.

METHODS

The medical records of 431 preterm infants, born between January 1, 2008, and June 1, 2015, with a gestational age (GA) of less than 31 weeks or birth weight (BW) of less than 1,250 g were reviewed. Information collected included pregnancy and birth history, neonatal characteristics, ROP status, comorbidities, and postnatal weight measurements at specified intervals. Infants diagnosed as having ROP and no ROP were compared.

RESULTS

Low weight velocity from day 7 to day 28 (P < .001), high weight velocity from birth to first day of full enteral feeding (FEF) (P < .001), long duration from birth to FEF (P < .001), and long duration from FEF to discharge/transfer (P < .001) were associated with ROP. After controlling for GA and BW, the durations, birth to FEF, and FEF to discharge/transfer remained significant (P < .05). In a multivariable logistic regression analysis adjusting for GA, bronchopulmonary dysplasia, and surgical ligation for patent ductus arteriosus, the only independent risk factor of ROP was duration from FEF to discharge/transfer (P < .05).

CONCLUSIONS

Low weight velocity from day 7 to day 28 may be a useful predictor for the development of ROP but is dependent on GA and BW. A delay to reach FEF, which is associated with comorbidities of ROP, appears to be a risk factor for ROP that is independent of GA and BW. [J Pediatr Ophthalmol Strabismus. 2019;56(3):168-172.].

Mycobacterial DnaB helicase intein as oxidative stress sensor

Inteins are widespread self-splicing protein elements emerging as potential post-translational environmental sensors. Here, we describe two inteins within one protein, the Mycobacterium smegmatis replicative helicase DnaB. These inteins, DnaBi1 and DnaBi2, have homology to inteins in pathogens, splice with vastly varied rates, and are differentially responsive to environmental stressors. Whereas DnaBi1 splicing is reversibly inhibited by oxidative and nitrosative insults, DnaBi2 is not. Using a reporter that measures splicing in a native intein-containing organism and western blotting, we show that H2O2 inhibits DnaBi1 splicing in M. smegmatis. Intriguingly, upon oxidation, the catalytic cysteine of DnaBi1 forms an intramolecular disulfide bond. We report a crystal structure of the class 3 DnaBi1 intein at 1.95 Å, supporting our findings and providing insight into this splicing mechanism. We propose that this cysteine toggle allows DnaBi1 to sense stress, pausing replication to maintain genome integrity, and then allowing splicing immediately when permissive conditions return.

Large-effect loci affect survival in Tasmanian devils (Sarcophilus harrisii) infected with a transmissible cancer

Identifying the genetic architecture of complex phenotypes is a central goal of modern biology, particularly for disease-related traits. Genome-wide association methods are a classical approach for identifying the genomic basis of variation in disease phenotypes, but such analyses are particularly challenging in natural populations due to sample size difficulties. Extensive mark-recapture data, strong linkage disequilibrium and a lethal transmissible cancer make the Tasmanian devil (Sarcophilus harrisii) an ideal model for such an association study. We used a RAD-capture approach to genotype 624 devils at ~16,000 loci and then used association analyses to assess the heritability of three cancer-related phenotypes: infection case-control (where cases were infected devils and controls were devils that were never infected), age of first infection and survival following infection. The SNP array explained much of the phenotypic variance for female survival (>80%) and female case-control (>61%). We found that a few large-effect SNPs explained much of the variance for female survival (~5 SNPs explained >61% of the total variance), whereas more SNPs (~56) of smaller effect explained less of the variance for female case-control (~23% of the total variance). By contrast, these same SNPs did not account for a significant proportion of phenotypic variance in males, suggesting that the genetic bases of these traits and/or selection differ across sexes. Loci involved with cell adhesion and cell-cycle regulation underlay trait variation, suggesting that the devil immune system is rapidly evolving to recognize and potentially suppress cancer growth through these pathways. Overall, our study provided necessary data for genomics-based conservation and management in Tasmanian devils.

Measuring fetal adipose tissue using 3D water-fat magnetic resonance imaging: a feasibility study

Purpose: Analysis of fetal adipose tissue volumes may provide useful insight towards assessment of overall fetal health, especially in cases with abnormal fetal growth. Here, we assess whether fetal adipose tissue volume can be reliably measured using 3D water-fat MRI, using a quantitative assessment of the lipid content of tissues.Materials and methods: Seventeen women with singleton pregnancies underwent a fetal MRI and water-only and fat-only images were acquired (modified 2-point Dixon technique). Water and fat images were used to generate a fat signal fraction (fat/(water + fat)) from which subcutaneous adipose tissue was segmented along the fetal trunk. Inter-rater (three readers) and intrarater reliability was assessed using intraclass-correlation coefficients (ICC) for 10 image sets. Relationships between adipose tissue measurements and gestational age and estimated fetal weight percentiles were examined.Results: The ICC of the inter-rater reliability was 0.936 (p < .001), and the ICC of the intrarater reliability was 0.992 (p < .001). Strong positive correlations were found between adipose tissue measurements (lipid volume, lipid volume/total fetal volume, mean fat signal fraction) and gestational age.Conclusions: 3D water-fat MRI can reliably measure volume and quantify lipid content of fetal subcutaneous adipose tissues.