Cardiac competence of the paraxial head mesoderm fades concomitant with a shift towards the head skeletal muscle programme.

The vertebrate head mesoderm provides the heart, the great vessels, some smooth and most head skeletal muscle, in addition to parts of the skull. It has been speculated that the ability to generate cardiac and smooth muscle is the evolutionary ground-state of the tissue. However, whether indeed the entire head mesoderm has generic cardiac competence, how long this may last, and what happens as cardiac competence fades, is not clear. Bone morphogenetic proteins (Bmps) are known to promote cardiogenesis. Using 41 different marker genes in the chicken embryo, we show that the paraxial head mesoderm that normally does not engage in cardiogenesis has the ability to respond to Bmp for a long time. However, Bmp signals are interpreted differently at different time points. Up to early head fold stages, the paraxial head mesoderm is able to read Bmps as signal to engage in the cardiac programme; the ability to upregulate smooth muscle markers is retained slightly longer. Notably, as cardiac competence fades, Bmp promotes the head skeletal muscle programme instead. The switch from cardiac to skeletal muscle competence is Wnt-independent as Wnt caudalises the head mesoderm and also suppresses Msc-inducing Bmp provided by the prechordal plate, thus suppressing both the cardiac and the head skeletal muscle programmes. Our study for the first time suggests a specific transition state in the embryo when cardiac competence is replaced by skeletal muscle competence. It sets the stage to unravel the cardiac-skeletal muscle antagonism that is known to partially collapse in heart failure.

Sleep-disordered Breathing in Pregnancy and after Delivery: Associations with Cardiometabolic Health.

Rationale: Knowledge gaps exist regarding health implications of sleep-disordered breathing (SDB) identified in pregnancy and/or after delivery. Objectives: To determine whether SDB in pregnancy and/or after delivery is associated with hypertension (HTN) and metabolic syndrome (MS). Methods: nuMoM2b-HHS (Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be Heart Health Study) (N = 4,508) followed participants initially recruited during their first pregnancy. Participants returned for a visit 2-7 years after pregnancy. This study examined a subgroup who underwent SDB assessments during their first pregnancy (n = 1,964) and a repeat SDB assessment after delivery (n = 1,222). Two SDB definitions were considered: 1) apnea-hypopnea index (AHI) ⩾ 5 and 2) oxygen desaturation index (ODI) ⩾ 5. Associations between SDB and incident HTN and MS were evaluated with adjusted risk ratios (aRRs). Measurements and Main Results: The aRR for MS given an AHI ⩾ 5 during pregnancy was 1.44 (95% confidence interval [CI], 1.08-1.93), but no association with HTN was found. ODI ⩾ 5 in pregnancy was associated with both an increased risk for HTN (aRR, 2.02; 95% CI, 1.30-3.14) and MS (aRR, 1.53; 95% CI, 1.19-1.97). Participants with an AHI ⩾ 5 in pregnancy that persisted after delivery were at higher risk for both HTN (aRR, 3.77; 95% CI, 1.84-7.73) and MS (aRR, 2.46; 95% CI, 1.59-3.76). Similar associations were observed for persistent ODI ⩾ 5 after delivery. Conclusions: An AHI ⩾ 5 in pregnancy was associated with an increased risk of MS. An ODI ⩾ 5 in pregnancy was significantly associated with both HTN and MS. Participants with persistent elevations in AHI and ODI during pregnancy and at 2-7 years after delivery were at the highest risk for HTN and MS. Clinical trial registered with www.clinicaltrials.gov (NCT02231398).

Association between Sleep Disordered Breathing and Neonatal Outcomes in Nulliparous Individuals.

OBJECTIVE: Our objective was to determine whether objectively measured sleep-disordered breathing (SDB) during pregnancy is associated with an increased risk of adverse neonatal outcomes in a cohort of nulliparous individuals. STUDY DESIGN: Secondary analysis of the nuMom2b sleep disordered breathing substudy was performed. Individuals underwent in-home sleep studies for SDB assessment in early (6-15 weeks' gestation) and mid-pregnancy (22-31 weeks' gestation). SDB was defined as an apnea-hypopnea index ≥5 events/h at either time point. The primary outcome was a composite outcome of respiratory distress syndrome, transient tachypnea of the newborn, or receipt of respiratory support, treated hyperbilirubinemia or hypoglycemia, large-for-gestational age, seizures treated with medications or confirmed by electroencephalography, confirmed sepsis, or neonatal death. Individuals were categorized into (1) early pregnancy SDB (6-15 weeks' gestation), (2) new onset mid-pregnancy SDB (22-31 weeks' gestation), and (3) no SDB. Log-binomial regression was used to calculate adjusted risk ratios (RR) and 95% confidence intervals (CIs) representing the association. RESULTS: Among 2,106 participants, 3% (n = 75) had early pregnancy SDB and 5.7% (n = 119) developed new-onset mid-pregnancy SDB. The incidence of the primary outcome was higher in the offspring of individuals with early (29.3%) and new onset mid-pregnancy SDB (30.3%) compared with individuals with no SDB (17.8%). After adjustment for maternal age, chronic hypertension, pregestational diabetes, and body mass index, new onset mid-pregnancy SDB conferred increased risk (RR = 1.43, 95% CI: 1.05, 1.94), where there was no longer statistically significant association between early pregnancy SDB and the primary outcome. CONCLUSION: New onset, mid-pregnancy SDB is independently associated with neonatal morbidity. KEY POINTS: · Sleep disordered breathing (SDB) is a common condition impacting pregnancy with known maternal risks.. · Objectively defined SDB in pregnancy was associated with a composite of adverse neonatal outcomes.. · New onset SDB in mid pregnancy conferred statistically significant increased risk..

To roll the eyes and snap a bite - function, development and evolution of craniofacial muscles.

Craniofacial muscles, muscles that move the eyes, control facial expression and allow food uptake and speech, have long been regarded as a variation on the general body muscle scheme. However, evidence has accumulated that the function of head muscles, their developmental anatomy and the underlying regulatory cascades are distinct. This article reviews the key aspects of craniofacial muscle and muscle stem cell formation and discusses how this differs from the trunk programme of myogenesis; we show novel RNAseq data to support this notion. We also trace the origin of head muscle in the chordate ancestors of vertebrates and discuss links with smooth-type muscle in the primitive chordate pharynx. We look out as to how the special properties of head muscle precursor and stem cells, in particular their competence to contribute to the heart, could be exploited in regenerative medicine.

Anatomical Survey Versus Fetal Echocardiograms for Diagnosis of Cardiac Defects with a Single Umbilical Artery Cases: A Retrospective Cohort Study and Diagnostic Meta-analysis.

OBJECTIVE: To determine the utility of fetal echocardiography in diagnosing cardiac defects in fetuses with a single umbilical artery (SUA). METHODS: A retrospective cohort study of prenatally diagnosed SUA was conducted over a 10-year period at a single institution. Cardiac anatomy on detailed anatomical survey was compared with fetal echocardiogram for fetuses with prenatally diagnosed SUA. A diagnostic meta-analysis of studies comparing fetal anatomical survey to fetal echocardiogram in fetuses with SUA between 2010 to 2019 was also performed. RESULTS: Three hundred and twenty fetuses with SUA were identified, 113 of which had completed both ultrasound and echocardiography. There were 36 cases of cardiac defects on prenatal echocardiogram and all had abnormal anatomical ultrasounds. There were zero cases of abnormal cardiac exams (0%) when the cardiac views on anatomical survey were normal. The sensitivity, specificity, positive predictive value and negative predictive value of ultrasound were 100%, 77%, 73% and 100%, respectively. A summary ROC curve demonstrated a high predictive value of routine anatomic survey for cardiac defects (AUC: 0.99). CONCLUSION: Anatomic survey is highly predictive in the detection of cardiac defects in fetuses with SUA. Fetal echocardiogram is unnecessary in SUA when cardiac views are normal on ultrasound.

Engrailed controls epaxial-hypaxial muscle innervation and the establishment of vertebrate three-dimensional mobility.

Chordates are characterised by contractile muscle on either side of the body that promotes movement by side-to-side undulation. In the lineage leading to modern jawed vertebrates (crown group gnathostomes), this system was refined: body muscle became segregated into distinct dorsal (epaxial) and ventral (hypaxial) components that are separately innervated by the medial and hypaxial motors column, respectively, via the dorsal and ventral ramus of the spinal nerves. This allows full three-dimensional mobility, which in turn was a key factor in their evolutionary success. How the new gnathostome system is established during embryogenesis and how it may have evolved in the ancestors of modern vertebrates is not known. Vertebrate Engrailed genes have a peculiar expression pattern as they temporarily demarcate a central domain of the developing musculature at the epaxial-hypaxial boundary. Moreover, they are the only genes known with this particular expression pattern. The aim of this study was to investigate whether Engrailed genes control epaxial-hypaxial muscle development and innervation. Investigating chick, mouse and zebrafish as major gnathostome model organisms, we found that the Engrailed expression domain was associated with the establishment of the epaxial-hypaxial boundary of muscle in all three species. Moreover, the outgrowing epaxial and hypaxial nerves orientated themselves with respect to this Engrailed domain. In the chicken, loss and gain of Engrailed function changed epaxial-hypaxial somite patterning. Importantly, in all animals studied, loss and gain of Engrailed function severely disrupted the pathfinding of the spinal motor axons, suggesting that Engrailed plays an evolutionarily conserved role in the separate innervation of vertebrate epaxial-hypaxial muscle.

Predictors of sleep-disordered breathing in pregnancy.

BACKGROUND: Sleep-disordered breathing (SDB) is common in pregnancy, but there are limited data on predictors. OBJECTIVES: The objective of this study was to develop predictive models of sleep-disordered breathing during pregnancy. STUDY DESIGN: Nulliparous women completed validated questionnaires to assess for symptoms related to snoring, fatigue, excessive daytime sleepiness, insomnia, and restless leg syndrome. The questionnaires included questions regarding the timing of sleep and sleep duration, work schedules (eg, shift work, night work), sleep positions, and previously diagnosed sleep disorders. Frequent snoring was defined as self-reported snoring ≥3 days per week. Participants underwent in-home portable sleep studies for sleep-disordered breathing assessment in early (6-15 weeks gestation) and mid pregnancy (22-31 weeks gestation). Sleep-disordered breathing was characterized by an apnea hypopnea index that included all apneas, plus hypopneas with ≥3% oxygen desaturation. For primary analyses, an apnea hypopnea index ≥5 events per hour was used to define sleep-disordered breathing. Odds ratios and 95% confidence intervals were calculated for predictor variables. Predictive ability of the logistic models was estimated with area under the receiver-operating-characteristic curves, along with sensitivities, specificities, and positive and negative predictive values and likelihood ratios. RESULTS: Among 3705 women who were enrolled, data were available for 3264 and 2512 women in early and mid pregnancy, respectively. The corresponding prevalence of sleep-disordered breathing was 3.6% and 8.3%, respectively. At each time point in gestation, frequent snoring, chronic hypertension, greater maternal age, body mass index, neck circumference, and systolic blood pressure were associated most strongly with an increased risk of sleep-disordered breathing. Logistic regression models that included current age, body mass index, and frequent snoring predicted sleep-disordered breathing in early pregnancy, sleep-disordered breathing in mid pregnancy, and new onset sleep-disordered breathing in mid pregnancy with 10-fold cross-validated area under the receiver-operating-characteristic curves of 0.870, 0.838, and 0.809. We provide a supplement with expanded tables, integrated predictiveness, classification curves, and an predicted probability calculator. CONCLUSION: Among nulliparous pregnant women, logistic regression models with just 3 variables (ie, age, body mass index, and frequent snoring) achieved good prediction of prevalent and incident sleep-disordered breathing. These results can help with screening for sleep-disordered breathing in the clinical setting and for future clinical treatment trials.

Evaluation of the mass transfer rate using computer simulation in a three-dimensional interwoven hollow fiber-type bioartificial liver.

OBJECTIVES: To determine the most efficient design of a hollow fiber-based bioreactor device for a bioartificial liver support system through comparative bioengineering evaluations. RESULTS: We compared two types of hollow fiber-based bioreactors, the interwoven-type bioreactor (IWBAL) and the dialyzer-type bioreactor (DBAL), by evaluating the overall mass transfer coefficient (K) and the convective coefficient (X). The creatinine and albumin mass transfer coefficients and convective coefficients were calculated using our mathematical model based on the homoporous theory and the modified Powell method. Additionally, using our model, we simulated the mass transport efficiency in clinical-scale BALs. The results of this experiment demonstrate that the mass transfer coefficients for creatinine and albumin increased proportionally with velocity with the IWBAL, and were consistently greater than that found with the DBAL. These differences were further enhanced in the simulation of the large-scale model. CONCLUSIONS: Our findings indicate that the IWBAL with its unique 30° cross hollow fiber design can provide greater solute removal and more efficient metabolism when compared to the conventional DBAL design.

Role of early second-trimester uterine artery Doppler screening to predict small-for-gestational-age babies in nulliparous women.

BACKGROUND: Trophoblastic invasion of the uterine spiral arteries substantially increases compliance to accommodate increased blood flow to the placenta. Failure of this process impedes uterine artery blood flow, and this may be detected by uterine artery Doppler flow studies. However, the clinical utility of uterine artery Doppler flow studies in the prediction of adverse pregnancy outcomes in a general population remains largely unknown. OBJECTIVE: We sought to determine the utility of early second-trimester uterine artery Doppler studies as a predictor of small-for-gestational-age neonates. STUDY DESIGN: Nulliparous women with a viable singleton pregnancy were recruited during their first trimester into an observational prospective cohort study at 8 institutions across the United States. Participants were seen at 3 study visits during pregnancy and again at delivery. Three indices of uterine artery Doppler flow (resistance index, pulsatility index, and diastolic notching) were measured in the right and left uterine arteries between 16 weeks 0 days' and 22 weeks 6 days' gestation. Test characteristics for varying thresholds in the prediction of small for gestational age (defined as birthweight <5th percentile for gestational age [Alexander growth curve]) were evaluated. RESULTS: Uterine artery Doppler indices, birthweight, and gestational age at birth were available for 8024 women. Birthweight <5th percentile for gestational age occurred in 358 (4.5%) births. Typical thresholds for the uterine artery Doppler indices were all associated with birthweight <5th percentile for gestational age (P < .0001 for each), but the positive predictive values for these cutoffs were all <15% and areas under receiver operating characteristic curves ranged from 0.50-0.60. Across the continuous scales for these measures, the areas under receiver operating characteristic curves ranged from 0.56-0.62. Incorporating maternal age, early pregnancy body mass index, race/ethnicity, smoking status prior to pregnancy, chronic hypertension, and pregestational diabetes in the prediction model resulted in only modest improvements in the areas under receiver operating characteristic curves ranging from 0.63-0.66. CONCLUSION: In this large prospective cohort, early second-trimester uterine artery Doppler studies were not a clinically useful test for predicting small-for-gestational-age babies.

Evolutionary Conservation of the Early Axon Scaffold in the Vertebrate Brain.

The early axon scaffold is the first axonal structure to appear in the rostral brain of vertebrates, paving the way for later, more complex connections. Several early axon scaffold components are conserved between all vertebrates; most notably two main ventral longitudinal tracts, the tract of the postoptic commissure and the medial longitudinal fascicle. While the overall structure is remarkably similar, differences both in the organization and the development of the early tracts are apparent. This review will bring together extensive data from the last 25 years in different vertebrates and for the first time, the timing and anatomy of these early tracts have been directly compared. Representatives of major vertebrate clades, including cat shark, Xenopus, chick, and mouse embryos, will be compared using immunohistochemistry staining based on previous results. There is still confusion over the nomenclature and homology of these tracts which this review will aim to address. The discussion here is relevant both for understanding the evolution of the early axon scaffold and for future studies into the molecular regulation of its formation.

The First Report of a Pregnancy in a Patient with Purine Nucleoside Phosphorylase Deficiency.

BACKGROUND: The cause of primary immunodeficiency has expanded to nearly 200 distinct disorders. An improved understanding of these disorders has resulted in decreased morbidity and mortality with reciprocal improved life expectancy. Obstetricians should have knowledge of primary immunodeficiency, as more women with these disorders will reach reproductive age. CASE: 21-year-old G1P0 with purine nucleoside phosphorylase (PNP) deficiency delivered a viable infant vaginally at 37 weeks. Although the patient's diagnosis and pregnancy placed her at increased risk for infection, she remained asymptomatic and infection-free throughout pregnancy. CONCLUSION: The management of pregnancy complicated by PNP deficiency requires strict immune surveillance and regimented immunoglobulin replacement.

NuMoM2b Sleep-Disordered Breathing study: objectives and methods.

OBJECTIVE: The objective of the Sleep Disordered Breathing substudy of the Nulliparous Pregnancy Outcomes Study Monitoring Mothers-to-be (nuMoM2b) is to determine whether sleep disordered breathing during pregnancy is a risk factor for adverse pregnancy outcomes. STUDY DESIGN: NuMoM2b is a prospective cohort study of 10,037 nulliparous women with singleton gestations that was conducted across 8 sites with a central Data Coordinating and Analysis Center. The Sleep Disordered Breathing substudy recruited 3702 women from the cohort to undergo objective, overnight in-home assessments of sleep disordered breathing. A standardized level 3 home sleep test was performed between 6(0)-15(0) weeks' gestation (visit 1) and again between 22(0)-31(0) weeks' gestation (visit 3). Scoring of tests was conducted by a central Sleep Reading Center. Participants and their health care providers were notified if test results met "urgent referral" criteria that were based on threshold levels of apnea hypopnea indices, oxygen saturation levels, or electrocardiogram abnormalities but were not notified of test results otherwise. The primary pregnancy outcomes to be analyzed in relation to maternal sleep disordered breathing are preeclampsia, gestational hypertension, gestational diabetes mellitus, fetal growth restriction, and preterm birth. RESULTS: Objective data were obtained at visit 1 on 3261 women, which was 88.1% of the studies that were attempted and at visit 3 on 2511 women, which was 87.6% of the studies that were attempted. Basic characteristics of the substudy cohort are reported in this methods article. CONCLUSION: The substudy was designed to address important questions regarding the relationship of sleep-disordered breathing on the risk of preeclampsia and other outcomes of relevance to maternal and child health.

Ethanol for preventing preterm birth in threatened preterm labor.

BACKGROUND: Preterm birth is the leading cause of death and disability in newborns worldwide. A wide variety of tocolytic agents have been utilized to delay birth for women in preterm labor. One of the earliest tocolytics utilized for this purpose was ethanol infusion, although this is not generally used in current practice due to safety concerns for both the mother and her baby. OBJECTIVES: To determine the efficacy of ethanol in stopping preterm labor, preventing preterm birth, and the impact of ethanol on neonatal outcomes. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2015) and reference lists of retrieved studies. SELECTION CRITERIA: We included randomized and quasi-randomized studies. Cluster-randomized trials and cross-over design trials were not eligible for inclusion. We only included studies published in abstract form if there was enough information on methods and relevant outcomes. Trials were included if they compared ethanol infusion to stop preterm labor versus placebo/control or versus other tocolytic drugs. DATA COLLECTION AND ANALYSIS: At least two review authors independently assessed studies for inclusion and risk of bias. At least two review authors independently extracted data. Data were checked for accuracy. MAIN RESULTS: Twelve trials involving 1586 women met inclusion criteria for this review. One trial did not report on the outcomes of interest in this review.Risk of bias of included studies: The included studies generally were of low quality based on inadequate reporting of methodology. Only three trials had low risk of bias for random sequence generation and one had low risk of bias for allocation concealment and participant blinding. Most studies were either high risk of bias or uncertain in these key areas. Comparison 1: Ethanol versus placebo/control (two trials, 77 women) Compared to controls receiving pain medications and dextrose solution, ethanol did not improve any of the primary outcomes: birth < 48 hours after trial entry (one trial, 35 women; risk ratio (RR) 0.93, 95% confidence interval (CI) 0.43 to 2.00), or neonatal mortality (one trial, 35 women; RR 1.06, 95% CI 0.31 to 3.58). Serious maternal adverse events and perinatal mortality were not reported by either of the two trials in this comparison. Maternal adverse events (overall) were not reported but one trial (42 women) reported that there were no maternal adverse events that required stopping or changing drug) in either group. One trial did report delay until delivery but this outcome was reported as a median with no mention of the standard deviation (median 19 days in ethanol group versus "less than 1" day in the glucose/water group). There were no differences in any secondary outcomes reported: preterm birth < 34 weeks or < 37 weeks; serious infant outcome; fetal alcohol syndrome/fetal alcohol spectrum disorder; or small-for-gestational age. Comparison 2: Ethanol versus other tocolytic (betamimetics) (nine trials, 1438 women) Compared to betamimetics (the only tocolytic used as a comparator in these studies), ethanol was associated with no clear difference in the rate of birth < 48 hours after trial entry (two trials, 130 women; average RR 1.12, 95% CI 0.53 to 2.37, Tau² = 0.19, I² = 59%), similar rates of perinatal mortality (six trials, 698 women; RR1.20, 95% CI 0.78 to 1.84), higher rates of neonatal mortality (eight trials, 1238 women; RR 1.43, 95% CI 1.02 to 2.02), higher rates of preterm birth < 34 weeks (two trials, 599 women; RR 1.56, 95% CI 1.11 to 2.19), higher rates of neonatal respiratory distress syndrome (three trials, 823 women; RR 1.76, 95% CI 1.33 to 2.33), and higher rates of low birthweight babies < 2500 g (five trials, 834 women; RR 1.30, 95% CI 1.09 to 1.54). These outcomes are likely all related to the lower incidence of preterm birth seen with other tocolytics, which for all these comparisons were betamimetics. Serious maternal adverse events were not reported in any of the nine trial reports. However, ethanol had a trend towards a lower rate of maternal adverse events requiring stopping or changing the drug (three trials, 214 women; RR 0.25, 95% CI 0.06 to 0.97). There were no differences in other secondary outcomes of preterm birth < 37 weeks, number of days delivery was delayed, or overall maternal adverse events.Planned sensitivity analysis, excluding quasi-randomized trials did not substantially change the results of the primary outcome analyses with the exception of neonatal mortality which no longer showed a clear difference between the ethanol and other tocolytic groups (3 trials, 330 women; RR 1.49, 95% CI 0.82 to 2.72). AUTHORS' CONCLUSIONS: This review is based on evidence from twelve studies which were mostly low quality. There is no evidence that to suggest that ethanol is an effective tocolytic compared to placebo. There is some evidence that ethanol may be better tolerated than other tocolytics (in this case betamimetics), but this result is based on few studies and small sample size and therefore should be interpreted with caution. Ethanol appears to be inferior to betamimetics for preventing preterm birth in threatened preterm labor.Ethanol is generally no longer used in current practice due to safety concerns for the mother and her baby. There is no need for new studies to evaluate the use of ethanol for preventing preterm birth in threatened preterm labour. However, it would be useful for long-term follow-up studies on the babies born to mothers from the existing studies in order to assess the risk of long-term neurodevelopmental status.

Dact gene expression profiles suggest a role for this gene family in integrating Wnt and TGF-ß signaling pathways during chicken limb development.

BACKGROUND: Dact gene family encodes multifunctional proteins that are important modulators of Wnt and TGF-ß signaling pathways. Given that these pathways coordinate multiple steps of limb development, we investigated the expression pattern of the two chicken Dact genes (Dact1 and Dact2) from early limb bud up to stages when several tissues are differentiating. RESULTS: During early limb development (HH24-HH30) Dact1 and Dact2 were mainly expressed in the cartilaginous rudiments of the appendicular skeleton and perichondrium, presenting expression profiles related, but distinct. At later stages of development (HH31-HH35), the main sites of Dact1 and Dact2 expression were the developing synovial joints. In this context, Dact1 expression was shown to co-localize with regions enriched in the nuclear ß-catenin protein, such as developing joint capsule and interzone. In contrast, Dact2 expression was restricted to the interzone surrounding the domains of bmpR-1b expression, a TGF-ß receptor with crucial roles during digit morphogenesis. Additional sites of Dact expression were the developing tendons and digit blastemas. CONCLUSIONS: Our data indicate that Dact genes are good candidates to modulate and, possibly, integrate Wnt and TGF-ß signaling during limb development, bringing new and interesting perspectives about the roles of Dact molecules in limb birth defects and human diseases.

Pseudomonoamniotic Pregnancy: Case Report and Review of Etiologic Considerations.

Pseudomonoamniotic gestations are increasingly recognized through sonographic surveillance of monochorionic twins, though etiologic factors remain undefined. We present a case of spontaneous pseudomonoamniotic twins and propose umbilical cord insertion proximity as a sonographic marker. Systematic review of the literature was performed and additional cases with similar findings were noted. Approximately 75% of reported cases (28/37) were deemed spontaneous and several included short inter-cord distances. Shunting of blood away from the membranes in the region between the cord insertions may be responsible for membrane rupture. Further investigation is needed into short inter-cord distance as a marker for monochorionic twins at risk to become a pseudomonoamniotic gestation.

Dact genes are chordate specific regulators at the intersection of Wnt and Tgf-ß signaling pathways.

BACKGROUND: Dacts are multi-domain adaptor proteins. They have been implicated in Wnt and Tgfß signaling and serve as a nodal point in regulating many cellular activities. Dact genes have so far only been identified in bony vertebrates. Also, the number of Dact genes in a given species, the number and roles of protein motifs and functional domains, and the overlap of gene expression domains are all not clear. To address these problems, we have taken an evolutionary approach, screening for Dact genes in the animal kingdom and establishing their phylogeny and the synteny of Dact loci. Furthermore, we performed a deep analysis of the various Dact protein motifs and compared the expression patterns of different Dacts. RESULTS: Our study identified previously not recognized dact genes and showed that they evolved late in the deuterostome lineage. In gnathostomes, four Dact genes were generated by the two rounds of whole genome duplication in the vertebrate ancestor, with Dact1/3 and Dact2/4, respectively, arising from the two genes generated during the first genome duplication. In actinopterygians, a further dact4r gene arose from retrotranscription. The third genome duplication in the teleost ancestor, and subsequent gene loss in most gnathostome lineages left extant species with a subset of Dact genes. The distribution of functional domains suggests that the ancestral Dact function lied with Wnt signaling, and a role in Tgfß signaling may have emerged with the Dact2/4 ancestor. Motif reduction, in particular in Dact4, suggests that this protein may counteract the function of the other Dacts. Dact genes were expressed in both distinct and overlapping domains, suggesting possible combinatorial function. CONCLUSIONS: The gnathostome Dact gene family comprises four members, derived from a chordate-specific ancestor. The ability to control Wnt signaling seems to be part of the ancestral repertoire of Dact functions, while the ability to inhibit Tgfß signaling and to carry out specialized, ortholog-specific roles may have evolved later. The complement of Dact genes coexpressed in a tissue provides a complex way to fine-tune Wnt and Tgfß signaling. Our work provides the basis for future structural and functional studies aimed at unraveling intracellular regulatory networks.

Two is better than one: a case of homozygous myotonic dystrophy type 1.

Myotonic dystrophy type 1 is an autosomal dominant condition caused by a trinucleotide CTG repeat expansion in the 3' untranslated region of the dystrophia myotonica protein kinase gene. The phenotypic features of myopathic facies, generalized weakness, and myotonia are thought to be dependent on repeat number, with larger expansions generally leading to earlier and/or more severe disease. The vast majority of individuals are heterozygous for an expanded allele and an allele in the normal range. In this clinical report, we describe two brothers with congenital myotonic dystrophy type 1. The younger of the two siblings is one of only 13 homozygous patients ever reported in the literature. He carries two expanded alleles: one with 1,170 repeats and the other with >100 repeats. We present his clinical picture in relation to his more severely affected heterozygous brother as well as other published homozygous cases. Finally, we discuss the inconsistency between repeat size and symptomatic expression as it applies to the current proposed mechanisms of myotonic dystrophy type 1 pathogenicity.

A review of synthetic and augmented training data for machine learning in ultrasonic non-destructive evaluation.

Ultrasonic Testing (UT) has seen increasing application of machine learning (ML) in recent years, promoting higher-level automation and decision-making in flaw detection and classification. Building a generalized training dataset to apply ML in non-destructive evaluation (NDE), and thus UT, is exceptionally difficult since data on pristine and representative flawed specimens are needed. Yet, in most UT test cases flawed specimen data is inherently rare making data coverage the leading problem when applying ML. Common data augmentation (DA) strategies offer limited solutions as they don't increase the dataset variance, which can lead to overfitting of the training data. The virtual defect method and the recent application of generative adversarial neural networks (GANs) in UT are sophisticated DA methods targeting to solve this problem. On the other hand, well-established research in modeling ultrasonic wave propagations allows for the generation of synthetic UT training data. In this context, we present a first thematic review to summarize the progress of the last decades on synthetic and augmented UT training data in NDE. Additionally, an overview of methods for synthetic UT data generation and augmentation is presented. Among numerical methods such as finite element, finite difference, and elastodynamic finite integration methods, semi-analytical methods such as general point source synthesis, superposition of Gaussian beams, and the pencil method as well as other UT modeling software are presented and discussed. Likewise, existing DA methods for one- and multidimensional UT data, feature space augmentation, and GANs for augmentation are presented and discussed. The paper closes with an in-detail discussion of the advantages and limitations of existing methods for both synthetic UT training data generation and DA of UT data to aid the decision-making of the reader for the application to specific test cases.

The Neuronal Circuit of the Dorsal Circadian Clock Neurons in Drosophila melanogaster.

Drosophila's dorsal clock neurons (DNs) consist of four clusters (DN1as, DN1ps, DN2s, and DN3s) that largely differ in size. While the DN1as and the DN2s encompass only two neurons, the DN1ps consist of ∼15 neurons, and the DN3s comprise ∼40 neurons per brain hemisphere. In comparison to the well-characterized lateral clock neurons (LNs), the neuroanatomy and function of the DNs are still not clear. Over the past decade, numerous studies have addressed their role in the fly's circadian system, leading to several sometimes divergent results. Nonetheless, these studies agreed that the DNs are important to fine-tune activity under light and temperature cycles and play essential roles in linking the output from the LNs to downstream neurons that control sleep and metabolism. Here, we used the Flybow system, specific split-GAL4 lines, trans-Tango, and the recently published fly connectome (called hemibrain) to describe the morphology of the DNs in greater detail, including their synaptic connections to other clock and non-clock neurons. We show that some DN groups are largely heterogenous. While certain DNs are strongly connected with the LNs, others are mainly output neurons that signal to circuits downstream of the clock. Among the latter are mushroom body neurons, central complex neurons, tubercle bulb neurons, neurosecretory cells in the pars intercerebralis, and other still unidentified partners. This heterogeneity of the DNs may explain some of the conflicting results previously found about their functionality. Most importantly, we identify two putative novel communication centers of the clock network: one fiber bundle in the superior lateral protocerebrum running toward the anterior optic tubercle and one fiber hub in the posterior lateral protocerebrum. Both are invaded by several DNs and LNs and might play an instrumental role in the clock network.

Development of the early axon scaffold in the rostral brain of the chick embryo.

The arrangement of the early nerve connections in the embryonic vertebrate brain follows a well-conserved pattern, forming the early axon scaffold. The early axon tracts have been described in a number of anamniote species and in mouse, but a detailed analysis in chick is lacking. We have used immunostaining, axon tracing and in situ hybridisation to analyse the development of the early axon scaffold in the embryonic chick brain in relation to the neuromeric organisation of the brain. The first tract to be formed is the medial longitudinal fascicle (MLF), shortly followed by the tract of the postoptic commissure to pioneer the ventral longitudinal tract system. The MLF was found to originate from three different populations of neurones located in the diencephalon. Neurones close to the dorsal midline of the mesencephalon establish the descending tract of the mesencephalic nucleus of the trigeminus. Their axons pioneer the lateral longitudinal tract. At later stages, the tract of the posterior commissure emerges in the caudal pretectum as the first transversal tract. It is formed by dorsally projecting axons from neurones located in the ventral pretectum, and by ventrally projecting axons from neurones located in the dorsal pretectum. The organisation of neurones and axons in the chick brain is similar to that described in the mouse, though tracts form in a different order and appear more clearly distinguished than in the mammalian model.