Attosecond pulse shaping using a seeded free-electron laser.

Attosecond pulses are central to the investigation of valence- and core-electron dynamics on their natural timescales1-3. The reproducible generation and characterization of attosecond waveforms has been demonstrated so far only through the process of high-order harmonic generation4-7. Several methods for shaping attosecond waveforms have been proposed, including the use of metallic filters8,9, multilayer mirrors10 and manipulation of the driving field11. However, none of these approaches allows the flexible manipulation of the temporal characteristics of the attosecond waveforms, and they suffer from the low conversion efficiency of the high-order harmonic generation process. Free-electron lasers, by contrast, deliver femtosecond, extreme-ultraviolet and X-ray pulses with energies ranging from tens of microjoules to a few millijoules12,13. Recent experiments have shown that they can generate subfemtosecond spikes, but with temporal characteristics that change shot-to-shot14-16. Here we report reproducible generation of high-energy (microjoule level) attosecond waveforms using a seeded free-electron laser17. We demonstrate amplitude and phase manipulation of the harmonic components of an attosecond pulse train in combination with an approach for its temporal reconstruction. The results presented here open the way to performing attosecond time-resolved experiments with free-electron lasers.

Wave packet dynamics and control in excited states of molecular nitrogen.

Wave packet interferometry with vacuum ultraviolet light has been used to probe a complex region of the electronic spectrum of molecular nitrogen, N2. Wave packets of Rydberg and valence states were excited by using double pulses of vacuum ultraviolet (VUV), free-electron-laser (FEL) light. These wave packets were composed of contributions from multiple electronic states with a moderate principal quantum number (n ∼ 4-9) and a range of vibrational and rotational quantum numbers. The phase relationship of the two FEL pulses varied in time, but as demonstrated previously, a shot-by-shot analysis allows the spectra to be sorted according to the phase between the two pulses. The wave packets were probed by angle-resolved photoionization using an infrared pulse with a variable delay after the pair of excitation pulses. The photoelectron branching fractions and angular distributions display oscillations that depend on both the time delays and the relative phases of the VUV pulses. The combination of frequency, time delay, and phase selection provides significant control over the ionization process and ultimately improves the ability to analyze and assign complex molecular spectra.

Rapport building with adolescents to enhance reporting and disclosure.

Adolescents comprise a vulnerable population that is exposed to crime and also may be reluctant to disclose full details of their experiences. Little research has addressed effective ways of increasing their willingness to disclose and provide complete reports. Strategies that improve honesty and report completeness in other age groups have not been evaluated to determine whether they are similarly effective at increasing adolescents' reporting. In the current study, we tested whether rapport building techniques, modified from those commonly used with children and adults to address reasons why adolescents are likely reluctant, enhance the amount of detail adolescents provide about prior experiences. The participants, 14- to 19-year-olds (N = 125), completed an online questionnaire regarding significant events (e.g., big argument with family member) they experienced during the last 12 months. After a delay, they completed a remote interview asking them to recount details of one of the events. The interview began with either standard rapport building composed of largely yes/no questions about the adolescents' background or one of two expanded rapport building phases: open-ended (questions about the adolescents' backgrounds that required narrative answers) or enhanced (open-ended questions paired with the interviewer also sharing personal information). Although only adolescents in the standard condition showed age-related increases in information disclosed, overall adolescents in the enhanced condition provided significantly longer and more detailed narratives than adolescents in the other conditions. This effect was largest for the youngest adolescents, suggesting that mutual self-disclosure may be especially beneficial for eliciting honest complete reports from adolescents about salient prior experiences.

Event characteristics help to explain the distribution of autobiographical memories over the first decade of life.

The shape of the distribution of autobiographical memories over the first decade of life is characterised by a paucity of memories from the early years followed by a gradual increase in the number of surviving memories. Though many events and experiences from this period are forgotten, some are well remembered. To better understand why certain memories survive, we examined characteristics of events recalled by young adolescents (12 - to 14-year-olds), sampled over their first decade of life, and whether they predict consistency in recall. Characteristics were assessed via third-party observer ratings of event narratives. Events with more negative emotional valence, lower frequency of occurrence, and that were culturally shared were more likely to be recalled. The details of events with less positive emotional valence, shorter duration, fewer changes in location, and less predictability were more consistently recalled. The characteristics of reported events were largely similar across the decade, with significant differences in the representation of event characteristics only between earliest memories (1-5 years) and later periods (6-10 years and the previous year). The findings suggest that event characteristics play a role in how consistently events are remembered and how memories are distributed over the first decade of life.

Chlamydia trachomatis conjunctivitis in the pre-pubertal child.

Much is reported in the literature about the transmission and presentation of Chlamydia trachomatis conjunctival infection in the neonate; however, there is a paucity of information available on infection in the older pre-pubertal child (>3 years of age). We present the case of a 7-year-old girl, referred for assessment at the sexual assault referral centre following the diagnosis of unilateral C. trachomatis conjunctivitis. This child underwent a rigorous multiagency child protection process, with input from medical professionals, social services and the police to investigate the possibility of child sexual abuse (CSA). However, a group consensus was reached that non-sexual close contact transfer of C. trachomatis from the mother was the most likely mode of transmission and cause of infection. We aim to take the reader through the complex path to this conclusion, the approach to sexually transmitted infections and potential CSA and what is currently known about chlamydial conjunctivitis in children beyond the neonatal period.

Reducing LGBTQ+ adolescent mental health inequalities: a realist review of school-based interventions.

BACKGROUND: LGBTQ+ young people have elevated rates of poor mental health in comparison to their cisgender heterosexual peers. School environment is a key risk factor and consistently associated with negative mental health outcomes for LGBTQ+ adolescents. AIMS: To examine how, why, for whom and in what context school-based interventions prevent or reduce mental health problems in LGBTQ+ adolescents. METHODS: A realist review methodology was utilised and focused on all types of school-based interventions and study designs. A Youth Advisory Group were part of the research team. Multiple search strategies were used to locate relevant evidence. Studies were subject to inclusion criteria and quality appraisal, and included studies were synthesised to produce a programme theory. Seventeen studies were included in the review. RESULTS: Eight intervention components were necessary to address LGBTQ+ pupils mental health: affirmative visual displays; external signposting to LGBTQ+ support; stand-alone input; school-based LGBTQ support groups; curriculum-based delivery; staff training; inclusion policies; trusted adult. Few school-based interventions for this population group were identified. CONCLUSIONS: The programme theory indicates that "to work" school-based interventions must have a "whole-school" approach that addresses specifically the dominant cis-heteronormative school environment and hence the marginalisation, silence, and victimisation that LGBTQ+ pupils can experience.

School culture and student mental health: a qualitative study in UK secondary schools.

BACKGROUND: There is consistency of evidence on the link between school culture and student health. A positive school culture has been associated with positive child and youth development, effective risk prevention and health promotion efforts, with extensive evidence for the impact on student mental health. Interventions which focus on socio-cultural elements of school life, and which involve students actively in the process, are increasingly understood to be important for student mental health promotion. This qualitative study was undertaken in three UK secondary schools prior to the implementation of a participative action research study bringing students and staff together to identify changes to school culture that might impact student mental health. The aim was to identify how school culture is conceptualised by students, parents and staff in three UK secondary schools. A secondary aim was to explore which components of school culture were perceived to be most important for student mental health. METHODS: Across three schools, 27 staff and seven parents participated in in-depth interviews, and 28 students participated in four focus groups. The Framework Method of thematic analysis was applied. RESULTS: Respondents identified elements of school culture that aligned into four dimensions; structure and context, organisational and academic, community, and safety and support. There was strong evidence of the interdependence of the four dimensions in shaping the culture of a school. CONCLUSIONS: School staff who seek to shape and improve school culture as a means of promoting student mental health may have better results if this interdependence is acknowledged, and improvements are addressed across all four dimensions.

What is the impact of structural and cultural factors and interventions within educational settings on promoting positive mental health and preventing poor mental health: a systematic review.

Mental health (MH) difficulties are on the increase among children and young people (CYP). Evidence has shown that educational settings contain both risk and protective factors for MH. This review investigated which structural and cultural factors and interventions within educational settings promote positive MH and prevent poor MH in 4-18 year olds. Searches were conducted in PsychINFO, Embase, ERIC, ASSIA and British Education Index, and reference lists from key studies and relevant systematic reviews were hand-searched. Intervention, cohort, and qualitative studies were included. Of the 62 included papers, 36 examined cultural factors (30 social/relational and six value-related) while 12 studies examined structural factors (eight organisational and four physical) and 14 studies examined multiple factors. There was strong evidence for the impact of positive classroom management techniques, access to physical activity, and peer mentoring on student MH. Studies examining the impact of positive school culture, teacher training in MH and parent involvement in school MH activities also found predominantly positive results for student MH, albeit the evidence was of lower quality or from a low number of studies. Few studies explicitly examined the impact of interventions on MH inequalities; those that did indicated limited if any reduction to inequalities. A very small number of studies suggested that interventions targeting those at risk of poor MH due to socioeconomic factors could successfully improve wellbeing and reduce depression, anxiety and behavioural problems. Studies exploring the effect of management and leadership strategies within schools, policies, and aspects of the physical environment other than green space were scarce or absent in the literature. This review highlights the need to consider the ways in which educational settings are organised, the culture that is created and the physical space in order to improve the MH of CYP.

Conceptualising public mental health: development of a conceptual framework for public mental health.

BACKGROUND: Numerous determinants have been linked to public mental health; however, they have not been brought together in a comprehensive conceptual framework. The goal of this work was to bring together academic research, practitioner expertise, and public perspectives to create a public mental health conceptual framework. METHODS: The development process proceeded in four stages. First, we identified a comprehensive list of potential determinants through a state-of-the-art academic literature review, grey literature review, and created mind maps created by peer researchers. Next, we conducted in-person workshops, consultations, and an online survey with academics, practitioners, policy makers, and members of the public to review the potential determinants, nominate additional determinants, and prioritise determinants by importance for understanding public mental health. This iterative process resulted in the final list of determinants contained in the framework. We then conducted rapid reviews to define each determinant and to identify key research, interventions, and resources. Finally, we worked with a design team to visualise the conceptual framework as an online tool and printable infographic. RESULTS: We found substantial overlap between sources reflecting a shared understanding of the key drivers of public mental health. The unique determinants that emerged from each data source highlighted the importance of using multiple sources to create a comprehensive model. 72 potential determinants were prioritised through stakeholder consultations, resulting in a final list of 55 determinants and organised into four levels: individual, family, community, and structural. CONCLUSIONS: This is the most complete conceptual framework for public mental health to date, bringing together academic research, policy and practitioner views, and lived experience perspectives. The co-production processes and tools we used provides a template for researchers looking to include multiple perspectives in their research. The conceptual framework draws together current knowledge on each determinant, but also highlights areas where further research is needed to better understand the relationship between each factor and mental health, which can inform the research agenda. This online tool and infographic can be used by practitioners to identify interventions for promoting mental health, and by the general public as a resource to increase awareness of the broad factors which shape public mental health.

Remotely monitored transcranial direct current stimulation in pediatric cerebral palsy: open label trial protocol.

BACKGROUND: Pediatric applications of non-invasive brain stimulation using transcranial direct current stimulation (tDCS) have demonstrated its safety with few adverse events reported. Remotely monitored tDCS, as an adjuvant intervention to rehabilitation, may improve quality of life for children with cerebral palsy (CP) through motor function improvements, reduced treatment costs, and increased access to tDCS therapies. Our group previously evaluated the feasibility of a remotely monitored mock tDCS setup in which families and children successfully demonstrated the ability to follow tDCS instructional guidance. METHODS AND DESIGN: Here, we designed a protocol to investigate the feasibility, safety, and tolerability of at-home active transcranial direct current stimulation in children with CP with synchronous supervision from laboratory investigators. Ten participants will be recruited to participate in the study for 5 consecutive days with the following sessions: tDCS setup practice on day 1, sham tDCS on day 2, and active tDCS on days 3-5. Sham stimulation will consist of an initial 30-second ramp up to 1.5 mA stimulation followed by a 30-second ramp down. Active stimulation will be delivered at 1.0 - 1.5 mA for 20 minutes and adjusted based on child tolerance. Feasibility will be evaluated via photographs of montage setup and the quality of stimulation delivery. Safety and tolerability will be assessed through an adverse events survey, the Box and Blocks Test (BBT) motor assessment, and a setup ease/comfort survey. DISCUSSION: We expect synchronous supervision of at-home teleneuromodulation to be tolerable and safe with increasing stimulation quality over repeated sessions when following a tDCS setup previously determined to be feasible. The findings will provide opportunity for larger clinical trials exploring efficacy and illuminate the potential of remotely monitored tDCS in combination with rehabilitation interventions as a means of pediatric neurorehabilitation. This will demonstrate the value of greater accessibility of non-invasive brain stimulation interventions and ultimately offer the potential to improve care and quality of life for children and families with CP. TRIAL REGISTRATION: October 8, 2021( https://clinicaltrials.gov/ct2/show/NCT05071586 ).

Spatial control of extreme ultraviolet light with opto-optical phase modulation.

Extreme ultraviolet (XUV) light is notoriously difficult to control due to its strong interaction cross section with media. We demonstrate a method to overcome this problem by using opto-optical modulation guided by a geometrical model to shape XUV light. A bell-shaped infrared light pulse is shown to imprint a trace of its intensity profile onto the XUV light in the far-field, such that a change in the intensity profile of the infrared pulse leads to a change in the shape of the far-field XUV light. The geometrical model assists the user in predicting the effect of a specific intensity profile of the infrared pulse, thus enabling a deterministic process.

Time-resolved photoelectron imaging of complex resonances in molecular nitrogen.

We have used the FERMI free-electron laser to perform time-resolved photoelectron imaging experiments on a complex group of resonances near 15.38 eV in the absorption spectrum of molecular nitrogen, N2, under jet-cooled conditions. The new data complement and extend the earlier work of Fushitani et al. [Opt. Express 27, 19702-19711 (2019)], who recorded time-resolved photoelectron spectra for this same group of resonances. Time-dependent oscillations are observed in both the photoelectron yields and the photoelectron angular distributions, providing insight into the interactions among the resonant intermediate states. In addition, for most states, we observe an exponential decay of the photoelectron yield that depends on the ionic final state. This observation can be rationalized by the different lifetimes for the intermediate states contributing to a particular ionization channel. Although there are nine resonances within the group, we show that by detecting individual photoelectron final states and their angular dependence, we can identify and differentiate quantum pathways within this complex system.

Parental responsibility for pediatric ventricular assist devices: Views of families on the acceptability of hospital discharge.

BACKGROUND: Paracorporeal pediatric VAD therapy requires hospital residency due to device and patient factors. Discharge home is potentially possible with a mobile driving unit. This study aimed to investigate family views on hospital discharge of a child on VAD. METHODS: Qualitative methodologies were adopted. We undertook 24 interviews of families who had a transplanted child previously on a VAD, and participant observations of two families who were current VAD patients residing in hospital. RESULTS: Families experienced overwhelming emotions as they spent time adjusting to the diagnosis, the need for transplant, family separation, and financial concerns. Despite many parents being partially/fully trained on the VAD, the majority would be reluctant to be discharged, fearing emergencies, high burden of care needs, and social isolation. Three families with a child on a Berlin Heart expressed willingness to reside in the hospital accommodation at least part-time, to facilitate private family time. One child on HeartWare was discharged home, with another going through the discharge process. Discharge was not acceptable to most families if this meant downgrading their child's transplant listing urgency status. CONCLUSION: Parents and children on VAD value independence and some private family time but not at the perceived expense of safety. Families preferred their child on VAD to remain resident in hospital even if mobility is improved with a mobile driving device. Parental education should acknowledge the high burden on families, risks of a remote setting and offer intermediate residency options. It cannot be assumed families want hospital discharge.

Rheumatoid arthritis treated with 6-months of first-line biologic or biosimilar therapy: an updated systematic review and network meta-analysis.

OBJECTIVES: The aim of this study was to estimate the effectiveness of first-line biologic disease modifying drugs(boDMARDs), and their approved biosimilars (bsDMARDs), compared with conventional (csDMARD) treatment, in terms of ACR (American College of Rheumatology) and EULAR (European League against Rheumatism) responses. METHODS: Systematic literature search, on eight databases to January 2017, sought ACR and EULAR data from randomized controlled trials (RCTs) of boDMARDs / bsDMARDs (in combination with csDMARDs, or monotherapy). Two adult populations: methotrexate (MTX)-naïve patients with severe active RA; and csDMARD-experienced patients with moderate-to-severe active RA. Network meta-analyses (NMA) were conducted using a Bayesian Markov chain Monte Carlo simulation using a random effects model with a probit link function for ordered categorical. RESULTS: Forty-six RCTs met the eligibility criteria. In the MTX-naïve severe active RA population, no biosimilar trials meeting the inclusion criteria were identified. MTX plus methylprednisolone (MP) was most likely to achieve the best ACR response. There was insufficient evidence that combination boDMARDs was superior to intensive (two or more) csDMARDs. In the csDMARD-experienced, moderate-to-severe RA population, the greatest effects for ACR responses were associated with tocilizumab (TCZ) monotherapy, and combination therapy (plus MTX) with bsDMARD etanercept (ETN) SB4, boDMARD ETN and TCZ. These treatments also had the greatest effects on EULAR responses. No clear differences were found between the boDMARDs and their bsDMARDs. CONCLUSIONS: In MTX-naïve patients, there was insufficient evidence that combination boDMARDs was superior to two or more csDMARDs. In csDMARD-experienced patients, boDMARDs and bsDMARDs were comparable and all combination boDMARDs / bsDMARDs were superior to single csDMARD.

Abnormal extracellular matrix remodelling in the cervix of pregnant relaxin-deficient mice is not associated with reduced matrix metalloproteinase expression or activity.

Relaxin regulates cervical extracellular matrix (ECM) remodelling during pregnancy by modifying collagen and other ECM molecules by unknown mechanisms. We hypothesised that abnormal collagen remodelling in the cervix of pregnant relaxin-deficient (Rln1-/-) mice is due to excessive collagen (Col1a1 and Col3a1) and decreased matrix metalloproteinases (Mmp2, Mmp9, Mmp13 and Mmp7) and oestrogen receptors (Esr1 and Esr2). Quantitative polymerase chain reaction, gelatinase zymography, MMP activity assays and histological staining evaluated changes in ECM in pregnant wildtype (Rln1+/+) and Rln1-/- mice. Cervical Col1a1, Col3a1 and total collagen increased in Rln1-/- mice and were higher at term compared with Rln1+/+ mice. This was not correlated with a decrease in gelatinase (Mmp2, Mmp9) expression or activity, Mmp7 or Mmp13 expression, which were all significantly higher in Rln1-/- mice. In late pregnancy, circulating MMP2 and MMP9 were unchanged. Esr1 expression was highest in Rln1+/+ and Rln1-/- mice in late pregnancy, coinciding with a decrease in Esr2 in Rln1+/+ but not Rln1-/- mice. The relaxin receptor (Rxfp1) decreased slightly in late-pregnant Rln1+/+ mice, but was significantly higher in Rln1-/- mice. In summary, relaxin deficiency results in increased cervical collagen in late pregnancy, which is not explained by a reduction in Mmp expression or activity or decreased Rxfp1. However, an imbalance between Esr1 and Esr2 may be involved.

Unexpected Sensitivity of Nitrogen Ions Superradiant Emission on Pump Laser Wavelength and Duration.

Nitrogen molecules in ambient air exposed to an intense near-infrared femtosecond laser pulse give rise to cavity-free superradiant emission at 391.4 and 427.8 nm. An unexpected pulse duration-dependent cyclic variation of the superradiance intensity is observed when the central wavelength of the femtosecond pump laser pulse is finely tuned between 780 and 820 nm, and no signal occurs at the resonant wavelength of 782.8 nm (2ω_{782.8 nm}=ω_{391.4 nm}). On the basis of a semiclassical recollision model, we show that an interference of dipolar moments of excited ions created by electron recollisions explains this behavior.

Regulation of neonatal and adult mammalian heart regeneration by the miR-15 family.

We recently identified a brief time period during postnatal development when the mammalian heart retains significant regenerative potential after amputation of the ventricular apex. However, one major unresolved question is whether the neonatal mouse heart can also regenerate in response to myocardial ischemia, the most common antecedent of heart failure in humans. Here, we induced ischemic myocardial infarction (MI) in 1-d-old mice and found that this results in extensive myocardial necrosis and systolic dysfunction. Remarkably, the neonatal heart mounted a robust regenerative response, through proliferation of preexisting cardiomyocytes, resulting in full functional recovery within 21 d. Moreover, we show that the miR-15 family of microRNAs modulates neonatal heart regeneration through inhibition of postnatal cardiomyocyte proliferation. Finally, we demonstrate that inhibition of the miR-15 family from an early postnatal age until adulthood increases myocyte proliferation in the adult heart and improves left ventricular systolic function after adult MI. We conclude that the neonatal mammalian heart can regenerate after myocardial infarction through proliferation of preexisting cardiomyocytes and that the miR-15 family contributes to postnatal loss of cardiac regenerative capacity.

Treatments for Hyperemesis Gravidarum and Nausea and Vomiting in Pregnancy: A Systematic Review.

Importance: Nausea and vomiting affects approximately 85% of pregnant women. The most severe form, hyperemesis gravidarum, affects up to 3% of women and can have significant adverse physical and psychological sequelae. Objective: To summarize current evidence on effective treatments for nausea and vomiting in pregnancy and hyperemesis gravidarum. Evidence Review: Databases were searched to June 8, 2016. Relevant websites and bibliographies were also searched. Titles and abstracts were assessed independently by 2 reviewers. Results were narratively synthesized; planned meta-analysis was not possible because of heterogeneity and incomplete reporting of findings. Findings: Seventy-eight studies (n = 8930 participants) were included: 67 randomized clinical trials (RCTs) and 11 nonrandomized studies. Evidence from 35 RCTs at low risk of bias indicated that ginger, vitamin B6, antihistamines, metoclopramide (for mild symptoms), pyridoxine-doxylamine, and ondansetron (for moderate symptoms) were associated with improved symptoms compared with placebo. One RCT (n = 86) reported greater improvements in moderate symptoms following psychotherapy (change in Rhodes score [range, 0 {no symptoms} to 40 {worst possible symptoms}], 18.76 [SD, 5.48] to 7.06 [SD, 5.79] for intervention vs 19.18 [SD, 5.63] to 12.81 [SD, 6.88] for comparator [P < .001]). For moderate-severe symptoms, 1 RCT (n = 60) suggested that pyridoxine-doxylamine combination taken preemptively reduced risk of recurrence of moderate-severe symptoms compared with treatment once symptoms begin (15.4% vs 39.1% [P < .04]). One RCT (n = 83) found that ondansetron was associated with lower nausea scores on day 4 than metoclopramide (mean visual analog scale [VAS] score, 4.1 [SD, 2.9] for ondansetron vs 5.7 [SD, 2.3] for metoclopramide [P = .023]) but not episodes of emesis (5.0 [SD, 3.1] vs 3.3 [SD, 3], respectively [P = .013]). Although there was no difference in trend in nausea scores over the 14-day study period, trend in vomiting scores was better in the ondansetron group (P = .042). One RCT (n = 159) found no difference between metoclopramide and promethazine after 24 hours (episodes of vomiting, 1 [IQR, 0-5] for metoclopramide vs 2 [IQR, 0-3] for promethazine [P = .81], VAS [0-10 scale] for nausea, 2 [IQR, 1-5] vs 2 [IQR, 1-4], respectively [P = .99]). Three RCTs compared corticosteroids with placebo or promethazine or metoclopramide in women with severe symptoms. Improvements were seen in all corticosteroid groups, but only a significant difference between corticosteroids vs metoclopramide was reported (emesis reduction, 40.9% vs 16.5% at day 2; 71.6% vs 51.2% at day 3; 95.8% vs 76.6% at day 7 [n = 40, P < .001]). For other interventions, evidence was limited. Conclusions and Relevance: For mild symptoms of nausea and emesis of pregnancy, ginger, pyridoxine, antihistamines, and metoclopramide were associated with greater benefit than placebo. For moderate symptoms, pyridoxine-doxylamine, promethazine, and metoclopramide were associated with greater benefit than placebo. Ondansetron was associated with improvement for a range of symptom severity. Corticosteroids may be associated with benefit in severe cases. Overall the quality of evidence was low.

MiR-15 family regulates postnatal mitotic arrest of cardiomyocytes.

RATIONALE: Mammalian cardiomyocytes withdraw from the cell cycle during early postnatal development, which significantly limits the capacity of the adult mammalian heart to regenerate after injury. The regulatory mechanisms that govern cardiomyocyte cell cycle withdrawal and binucleation are poorly understood. OBJECTIVE: Given the potential of microRNAs (miRNAs) to influence large gene networks and modify complex developmental and disease phenotypes, we searched for miRNAs that were regulated during the postnatal switch to terminal differentiation. METHODS AND RESULTS: Microarray analysis revealed subsets of miRNAs that were upregulated or downregulated in cardiac ventricles from mice at 1 and 10 days of age (P1 and P10). Interestingly, miR-195 (a member of the miR-15 family) was the most highly upregulated miRNA during this period, with expression levels almost 6-fold higher in P10 ventricles relative to P1. Precocious overexpression of miR-195 in the embryonic heart was associated with ventricular hypoplasia and ventricular septal defects in ß-myosin heavy chain-miR-195 transgenic mice. Using global gene profiling and argonaute-2 immunoprecipitation approaches, we showed that miR-195 regulates the expression of a number of cell cycle genes, including checkpoint kinase 1 (Chek1), which we identified as a highly conserved direct target of miR-195. Finally, we demonstrated that knockdown of the miR-15 family in neonatal mice with locked nucleic acid-modified anti-miRNAs was associated with an increased number of mitotic cardiomyocytes and derepression of Chek1. CONCLUSIONS: These findings suggest that upregulation of the miR-15 family during the neonatal period may be an important regulatory mechanism governing cardiomyocyte cell cycle withdrawal and binucleation.

DNA Methylation and Counterdirectional Pigmentation Change following Immune Challenge in a Small Ectotherm.

AbstractBy allowing for increased absorption or reflectance of solar radiation, changes in pigmentation may assist ectotherms in responding to immune challenges by enabling a more precise regulation of behavioral fever or hypothermia. Variation in epigenetic characteristics may also assist in regulating immune-induced pigmentation changes and managing the body's energetic reserves following infection. Here, we explore how dorsal pigmentation, metabolic rate, and DNA methylation in the Florida scrub lizard (Sceloporus woodi) respond to two levels of immune challenge across two habitat types. We found changes in pigmentation that are suggestive of efforts to assist in behavioral fever and hypothermia depending on the intensity of immune challenge. We also found correlations between DNA methylation in liver tissue and pigmentation change along the dorsum, indicating that color transitions may be part of a multifaceted immune response across tissue types. The relationship between immune response and metabolic rate supports the idea that energetic reserves may be conserved for the costs associated with behavioral fever when immune challenge is low and the immune functions when immune challenge is high. While immune response appeared to be unaffected by habitat type, we found differences in metabolic activity between habitats, suggesting differences in the energetic costs associated with each. To our knowledge, these results present the first potential evidence of pigmentation change in ectotherms in association with immune response. The relationship between immune response, DNA methylation, and pigmentation change also highlights the importance of epigenetic mechanisms in organism physiology.