Altered 5-HT2A/C receptor binding in the medulla oblongata in the sudden infant death syndrome (SIDS): Part II. Age-associated alterations in serotonin receptor binding profiles within medullary nuclei supporting cardiorespiratory homeostasis

The failure of chemoreflexes, arousal, and/or autoresuscitation to asphyxia may underlie some sudden infant death syndrome (SIDS) cases. In Part I, we showed that some SIDS infants had altered 5-hydroxytryptamine (5-HT)2A/C receptor binding in medullary nuclei supporting chemoreflexes, arousal, and autoresuscitation. Here, using the same dataset, we tested the hypotheses that the prevalence of low 5-HT1A and/or 5-HT2A/C receptor binding (defined as levels below the 95% confidence interval of controls-a new approach), and the percentages of nuclei affected are greater in SIDS versus controls, and that the distribution of low binding varied with age of death. The prevalence and percentage of nuclei with low 5-HT1A and 5-HT2A/C binding in SIDS were twice that of controls. The percentage of nuclei with low 5-HT2A/C binding was greater in older SIDS infants. In >80% of older SIDS infants, low 5-HT2A/C binding characterized the hypoglossal nucleus, vagal dorsal nucleus, nucleus of solitary tract, and nuclei of the olivocerebellar subnetwork (important for blood pressure regulation). Together, our findings from SIDS infants and from animal models of serotonergic dysfunction suggest that some SIDS cases represent a serotonopathy. We present new hypotheses, yet to be tested, about how defects within serotonergic subnetworks may lead to SIDS.

Attention challenges in Kabuki syndrome

BACKGROUND

Understanding the specific neurobehavioural profile of rare genetic diseases enables clinicians to provide the best possible care for patients and families, including prognostic and treatment advisement. Previous studies suggested that a subset of individuals with Kabuki syndrome (KS), a genetic disorder causing intellectual disability and other neurodevelopmental phenotypes, have attentional deficits. However, these studies looked at relatively small numbers of molecularly confirmed cases and often used retrospective clinical data instead of standardised assessments.

METHODS

Fifty-five individuals or caregivers of individuals with molecularly confirmed KS completed assessments to investigate behaviour and adaptive function. Additionally, information was collected on 23 unaffected biological siblings as controls.

RESULTS

Attention Problems in children was the only behavioural category that, when averaged, was clinically significant, with the individual scores of nearly 50% of the children with KS falling in the problematic range. Children with KS scored significantly higher than their unaffected sibling on nearly all behavioural categories. A significant correlation was found between Attention Problems scores and adaptive function scores (P = 0.032), which was not explained by lower general cognitive ability.

CONCLUSIONS

We found that the rates of children with attentional deficits are much more elevated than would be expected in the general population, and that attention challenges are negatively correlated with adaptive function. When averaged across KS participants, none of the behavioural categories were in the clinically significant range except Attention Problems for children, which underscores the importance of clinicians screening for attention deficit hyperactivity disorder (ADHD) in children with KS.

Distinct Reproductive Phenotypes Segregate With Differences in Body Weight in Adolescent Polycystic Ovary Syndrome

Introduction

Polycystic ovary syndrome (PCOS) is a heterogenous clinical syndrome defined by hyperandrogenism and irregular menses. In adult women with PCOS, discrete metabolic and reproductive subgroups have been identified. We hypothesize that distinct phenotypes can be distinguished between adolescent girls who are lean (LN-G) and girls with obesity (OB-G) at the time of PCOS diagnosis.

Methods

Data were extracted from the CALICO multisite PCOS database. Clinical data collected at the time of diagnosis were available in 354 patients (81% with obesity) from 7 academic centers. Patients with body mass index (BMI) < 85th percentile for age and sex were characterized as lean (LN-G) and those with BMI percentile ≥ 95th percentile as obese (OB-G). We compared metabolic and reproductive phenotypes in LN-G and OB-G.

Results

Reproductive phenotypes differed between the groups, with LN-G having higher total testosterone, androstenedione, and LH levels, while OB-G had lower sex hormone binding globulin (SHBG) and higher free testosterone. Metabolic profiles differed as expected, with OB-G having higher hemoglobin A1c, alanine aminotransferase, and serum triglycerides and more severe acanthosis nigricans.

Conclusion

LN-G with PCOS had a distinct reproductive phenotype characterized by increased LH, total testosterone, and androstenedione levels, suggesting neuroendocrine-mediated ovarian androgen production. In contrast, phenotypes in OB-G suggest hyperandrogenemia is primarily driven by insulin resistance with low SHBG levels. These observations support the existence of distinct metabolic and reproductive subtypes in adolescent PCOS characterized by unique mechanisms for hyperandrogenemia.

Crucial Roles of the Mesenchymal Androgen Receptor in Wolffian Duct Development

Wolffian duct (WD) maintenance and differentiation is predominantly driven by the androgen action, which is mediated by the androgen receptor (AR). It is well established that the mesenchyme indicates the fate and differentiation of epithelial cells. However, in vivo developmental requirement of mesenchymal AR in WD development is still undefined. By designing a mesenchyme-specific Ar knockout (ARcKO), we discovered that the loss of mesenchymal Ar led to the bilateral or unilateral degeneration of caudal WDs and cystic formation at the cranial WDs. Ex vivo culture of ARcKO WDs invariably resulted in bilateral defects, suggesting that some factor(s) originating from surrounding tissues in vivo might promote WD survival and growth even in the absence of mesenchymal Ar. Mechanistically, we found cell proliferation was significantly reduced in both epithelial and mesenchymal compartments; but cell apoptosis was not affected. Transcriptomic analysis by RNA sequencing of E14.5 mesonephroi revealed 131 differentially expressed genes. Multiple downregulated genes (Top2a, Wnt9b, Lama2, and Lamc2) were associated with morphological and cellular changes in ARcKO male embryos (ie, reduced cell proliferation and decreased number of epithelial cells). Mesenchymal differentiation into smooth muscle cells that are critical for morphogenesis was also impaired in ARcKO male embryos. Taken together, our results demonstrate the crucial roles of the mesenchymal AR in WD maintenance and morphogenesis in mice.

In-utero exposure to antibiotics and risk of colorectal cancer in a prospective cohort of 18 000 adult offspring

BACKGROUND

Incidence rates of colorectal cancer (CRC) are increasing among younger adults and in mid-life, implicating exposures in early life as risk factors. We examined the association between in-utero exposure to antibiotics and risk of CRC in adult offspring.

METHODS

The Child Health and Development Studies is a prospective cohort of women receiving prenatal care between 1959 and 1966 in Oakland, California, with deliveries through June 1967. Diagnosed conditions and all prescribed medications were abstracted from mothers' medical records beginning 6 months prior to pregnancy through delivery. We identified mothers who received antibiotics in pregnancy, including penicillins, tetracyclines, short-acting sulfonamides and long-acting sulfonamides. Diagnoses of CRC in adult (age ≥18 years) offspring were ascertained through 2021 by linkage with the California Cancer Registry. Cox proportional models were used to estimate adjusted hazard ratios (aHR), with follow-up accrued from birth through cancer diagnosis, death or last contact.

RESULTS

Of 18 751 liveborn offspring, about 15% (n = 2635) were exposed in utero to antibiotics: 5.4% (n = 1016) to tetracyclines, 4.9% (n = 918) to penicillins, 4.2% (n = 785) to short-acting sulfonamides and 1.5% (n = 273) to long-acting sulfonamides. Compared with offspring not exposed, associations between in-utero exposure and CRC in adult offspring were: aHR 1.03 (95% CI 0.32, 3.31) for tetracyclines; aHR 1.12 (95% CI 0.35, 3.58) for penicillins; aHR 0.83 (95% CI 0.20, 3.42) for short-acting sulfonamides; and aHR 4.40 (95% CI 1.63, 11.88) for long-acting sulfonamides.

CONCLUSION

Our findings support an association between in-utero exposure to long-acting sulfonamides and CRC in adulthood.

Altered 5-HT2A/C receptor binding in the medulla oblongata in the sudden infant death syndrome (SIDS): Part I. Tissue-based evidence for serotonin receptor signaling abnormalities in cardiorespiratory- and arousal-related circuits

The sudden infant death syndrome (SIDS), the leading cause of postneonatal infant mortality in the United States, is typically associated with a sleep period. Previously, we showed evidence of serotonergic abnormalities in the medulla (e.g. altered serotonin (5-HT)1A receptor binding), in SIDS cases. In rodents, 5-HT2A/C receptor signaling contributes to arousal and autoresuscitation, protecting brain oxygen status during sleep. Nonetheless, the role of 5-HT2A/C receptors in the pathophysiology of SIDS is unclear. We hypothesize that in SIDS, 5-HT2A/C receptor binding is altered in medullary nuclei that are key for arousal and autoresuscitation. Here, we report altered 5-HT2A/C binding in several key medullary nuclei in SIDS cases (n = 58) compared to controls (n = 12). In some nuclei the reduced 5-HT2A/C and 5-HT1A binding overlapped, suggesting abnormal 5-HT receptor interactions. The data presented here (Part 1) suggest that a subset of SIDS is due in part to abnormal 5-HT2A/C and 5-HT1A signaling across multiple medullary nuclei vital for arousal and autoresuscitation. In Part II to follow, we highlight 8 medullary subnetworks with altered 5-HT receptor binding in SIDS. We propose the existence of an integrative brainstem network that fails to facilitate arousal and/or autoresuscitation in SIDS cases.

Relationship between piperacillin concentrations, clinical factors and piperacillin/tazobactam-associated acute kidney injury

BACKGROUND

Piperacillin/tazobactam, a commonly used antibiotic, is associated with acute kidney injury (AKI). The relationship between piperacillin concentrations and AKI remains unknown.

OBJECTIVE

Estimate piperacillin exposures in critically ill children and young adults administered piperacillin/tazobactam to identify concentrations and clinical factors associated with piperacillin-associated AKI.

PATIENTS AND METHODS

We assessed piperacillin pharmacokinetics in 107 patients admitted to the paediatric ICU who received at least one dose of piperacillin/tazobactam. Piperacillin AUC, highest peak (Cmax) and highest trough (Cmin) in the first 24 hours of therapy were estimated. Piperacillin-associated AKI was defined as Kidney Disease: Improving Global Outcomes (KDIGO) Stage 2/3 AKI present >24 hours after initial piperacillin/tazobactam dose. Likelihood of piperacillin-associated AKI was rated using the Naranjo Adverse Drug Reaction Probability Scale. Multivariable logistic regression was performed to identify patient and clinical predictors of piperacillin-associated AKI.

RESULTS

Out of 107 patients, 16 (15%) were rated as possibly or probably having piperacillin-associated AKI. Estimated AUC and highest Cmin in the first 24 hours were higher in patients with piperacillin-associated AKI (2042 versus 1445 mg*h/L, P = 0.03; 50.1 versus 10.7 mg/L, P < 0.001). Logistic regression showed predictors of piperacillin-associated AKI included higher Cmin (OR: 5.4, 95% CI: 1.7-23) and age (OR: 1.13, 95% CI: 1.05-1.25).

CONCLUSIONS

We show a relationship between estimated piperacillin AUC and highest Cmin in the first 24 hours of piperacillin/tazobactam therapy and piperacillin-associated AKI, suggesting total piperacillin exposure early in the course is associated with AKI development. These data could serve as the foundation for implementation of model-informed precision dosing to reduce AKI incidence in patients given piperacillin/tazobactam.

Associations between sexual assault and suicidal thoughts and behavior: A meta-analysis

OBJECTIVE

The goal of the present study was to conduct a quantitative review to determine the degree to which specific forms of suicidality (i.e., lifetime and past-year suicidal ideation and attempts) are associated with sexual assault (SA). It also examined whether the strength of the association between SA and suicidality was moderated by sample characteristics or the type of suicidality assessed.

METHOD

A subset of studies (25 samples and 36 effects, reflecting N = 88,376 participants) from a prior meta-analysis assessing associations between SA and psychopathology was examined. Included studies provided the prevalence of suicidality in subsamples that had and had not been exposed to SA and/or an odds ratio comparing the prevalence in these groups. Random effects metaregression models aggregated prevalence estimates and odds ratios for lifetime and past-year suicidal ideation and suicide attempts in individuals in SA and no-SA groups. Analyses also examined whether sample characteristics (i.e., percent women, college sample) or type of suicidality moderated the magnitude of odds ratios.

RESULTS

Subsamples exposed to SA reported a substantially higher prevalence of suicidality (27.25%) compared with unassaulted subsamples (9.37%). There were significantly higher rates of lifetime and past-year suicidal ideation, and lifetime suicide attempts in assaulted subsamples than in unassaulted subsamples. No tested moderators had significant associations with the strength of the relationship between SA and suicidality.

CONCLUSION

Findings underscore the robust relationship between SA and both suicidal ideation and attempts and suggest that identifying moderators and mediators that explain it is a key directive for future research. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Contribution of the Wolffian duct mesenchyme to the formation of the female reproductive tract

The female reproductive tract develops from its embryonic precursor, the Müllerian duct. In close proximity to the Müllerian duct lies the precursor for the male reproductive tract, the Wolffian duct, which is eliminated in the female embryo during sexual differentiation. We discovered that a component of the Wolffian duct, its mesenchyme, is not eliminated after sexual differentiation. Instead, the Wolffian duct mesenchyme underwent changes in transcriptome and chromatin accessibility from male tract to female tract identity, and became a unique mesenchymal population in the female reproductive tract with localization and transcriptome distinct from the mesenchyme derived from the Müllerian duct. Partial ablation of the Wolffian duct mesenchyme stunted the growth of the fetal female reproductive tract in ex vivo organ culture. These findings reveal a new fetal origin of mesenchymal tissues for female reproductive tract formation and reshape our understanding of sexual differentiation of reproductive tracts.

Path Dependence in Disability

The average prevalence of disability in most African countries is 10%, but for many it exceeds the global disability prevalence rate of 15%. The extent to which this disability capturing functional and activity limitations results in permanent job loss, lowered lifetime income and assets, in part, depends upon the extent to which the onset of limitations becomes permanent. In this paper, we use five rounds of longitudinal data from rural Malawi, a low-income African country with high prevalence of disability, to examine path dependence in activity limitations. We estimate a dynamic linear panel data model where the coefficient on the one-period lagged health outcome captures path dependence in limitations. Our preferred Arellano-Bover estimates show that males experience partial persistence in both the incidence and intensity of severe limitations and no persistence in other limitations. Females, on the other hand, exhibit no persistence in any type of limitations. Our findings have important policy implications for computing the long-term costs associated with onset of activity limitations as these costs can be moderated by the recovery exhibited in these limitations.

Vertical Education-Occupation Mismatch and Wage Inequality by Race/Ethnicity and Nativity among Highly Educated US Workers

Despite remarkable educational gains of minorities, ethnoracial wage inequality persists and has even expanded among highly educated workers. Conventional explanations for this inequality are primarily derived from comparing workers across different educational levels and are less salient for understanding inequalities within the highly educated workforce. This study examines a previously overlooked source of ethnoracial inequality among highly educated workers: vertical mismatch between workers' educational level and the education requirements for their occupation. Using a longitudinal sample of college graduates from the Survey of Income and Program Participation, we find that vertical mismatch accounts for a large part of racial/ethnic and nativity wage inequality. Specifically, highly educated minorities (especially blacks and Hispanics) and immigrants (especially those holding a foreign degree) are disproportionately channeled into mismatched jobs and subsequently consigned to such positions. Also, highly educated Hispanics and Asians, as well as foreign-educated immigrants, face greater wage penalties of vertical mismatch. The findings offer new insights into a key source of ethnoracial and nativity stratification.

The principles of Nurturing Care promote human capital and mitigate adversities from preconception through adolescence

A comprehensive evidence-based framework is needed to guide policies and programmes that enable children and adolescents to accrue the human capital required to meet the Sustainable Development Goals (SDGs). This paper proposes a comprehensive, multisectoral, multilevel life-course conceptualisation of human capital development by building on the Nurturing Care Framework (NCF), originally developed for the foundational period of growth and development through the age 3 years. Nurturing care (NC) comprises stable environments that promote children's health and nutrition, protect from threats, and provide opportunities for learning and responsive, emotionally supportive and developmentally enriching relationships. NC is fostered by families, communities, services, national policies and beyond. The principles apply across the life course, endorse equity and human rights, and promote long-term human capital. This paper presents an evidence-based argument for the extension of the NCF from preconception through adolescence (0-20 years), organised into six developmental periods: preconception/prenatal, newborn/birth, infancy/toddlerhood, preschool, middle childhood and adolescence. The proposed framework advances human capital within each developmental period by promoting resilience and adaptive developmental trajectories while mitigating negative consequences of adversities.Attaining the SDGs depends on strengthening human capital formation, extending throughout childhood and adolescence and supported by NC. Embedded in enabling laws, policies and services, the dynamic NCF components can mitigate adversities, enhance resilience and promote the well-being of marginalised groups. The life-course extension of the NCF is strategically positioned to enhance human capital, to attain the SDGs and to ensure that children or adolescents are not left behind in reaching their developmental potential.

The Schizotypal Personality Questionnaire for Children (SPQ-C): Factor Structure, Child Abuse, and Family History of Schizotypy

There is a relative dearth of research on features of schizotypal personality in children, in part due to lack of instrumentation. This study tests 5 competing models of the factor structure of the self-report Schizotypal Personality Questionnaire for Children (SPQ-C) and examines its relationship with a family history of schizotypal personality disorder (SPD), child abuse, and stability over time. Hypotheses were tested on 454 11- to 12-year-old schoolchildren and their caregivers. Confirmatory factor analyses supported a 3-factor structure of the SPQ-C (cognitive-perceptual, interpersonal, and disorganized). Test-retest stability was relatively robust over 3 months (r = .67), 6 months (r = .64), and 12 months (r = .55), with acceptable internal reliabilities (r = .84 to .91). Regarding construct validity, children with a biological family history of SPD had higher scores on all 3 factors (d =.51). Abused children had higher schizotypy scores (d = .55). A genetic × environment interaction was observed, with schizotypy highest in those with both a family history of schizotypy and also child abuse. Findings are the first in the child schizotypy field to document a gene × environment interaction and the independence of child abuse from confounding genetic influences. Results support the utility of the SPQ-C in future family and clinical studies of schizotypal personality and provide an avenue for much-needed and neglected research into the early antecedents of child schizotypal personality.

Programmatic evaluation of feasibility and efficiency of at birth and 6-week, point of care HIV testing in Kenyan infant

Background

Testing infants at birth and with more efficient point of care (POC) HIV diagnostic can streamline EID and expedite infant ART initiation. We evaluated the implementation of at birth and 6-week POC testing to assess the effectiveness and feasibility when implemented by existing hospital staff in Kenya.

Methods

Four government hospitals were randomly assigned to receive a GeneXpert HIV-1 Qual (n = 2) or Alere m-PIMA (n = 2) machine for POC testing. All HIV-exposed infants enrolled were eligible to receive POC testing at birth and 6-weeks of age. The primary outcome was repeat POC testing, defined as testing both at birth and 6-weeks of age. Secondary outcomes included predictors of repeat POC testing, POC efficiency (turnaround times of key services), and operations (failed POC results, missed opportunities).

Results

Of 626 enrolled infants, 309 (49.4%) received repeat POC testing, 115 (18.4%) were lost to follow up after an at-birth test, 120 (19.2%) received POC testing at 6-weeks only, 80 (12.8%) received no POC testing, and 2 (0.3%) received delayed POC testing (>12 weeks of age). Three (0.4%) were identified as HIV-positive. Of the total 853 POC tests run at birth (n = 424) or 6-weeks (n = 429), 806 (94.5%) had a valid result documented and 792 (98.3%) results had documented maternal notification. Mean time from sample collection to notification was 1.08 days, with 751 (94.8%) notifications on the same day as sample collection. Machine error rates at birth and 6-weeks were 8.5% and 2.5%, respectively. A total of 198 infants presented for care (48 at birth; 150 at 6-weeks) without receiving a POC test, representing missed opportunities for testing.

Discussion

At birth POC testing can streamline infant HIV diagnosis, expedite ART initiation and can be implemented by existing hospital staff. However, maternal disengagement and missed opportunities for testing must be addressed to realize the full benefits of at birth POC testing.

Patterns of Risk and Protective Factors Among Alaska Children: Association With Maternal and Child Well-Being

This study used population-representative data to examine associations of risk and protective factor patterns among Alaska Native/American Indian (AN/AI; N = 592) and non-Native (N = 1,018) children with maternal and child outcomes at age 3 years. Among AN/AI children, a high risk/moderate protection class was associated with child developmental risk and mothers being less likely to feel comfortable asking for help or knowing where to go for parenting information compared to a low socioeconomic status/high protection class. Among non-Native children, a moderate risk/high protection class was associated with child developmental risk and mothers being less likely to feel comfortable asking for help compared to a low risk/high protection class. Results provide insight on the intersection of risk and protective factors among Alaska families.

Estimating retention in HIV care accounting for clinic transfers using electronic medical records: evidence from a large antiretroviral treatment programme in the Western Cape, South Africa

BACKGROUND

Estimates of retention in antiretroviral treatment (ART) programmes may be biased if patients who transfer to healthcare clinics are misclassified as lost to follow-up (LTFU) at their original clinic. In a large cohort, we estimated retention in care accounting for patient transfers using medical records.

METHODS

Using linked electronic medical records, we followed adults living with HIV (PLWH) in Cape Town, South Africa from ART initiation (2012-2016) through database closure at 36 months or 30 June 2016, whichever came first. Retention was defined as alive and with a healthcare visit in the 180 days between database closure and administrative censoring on 31 December 2016. Participants who died or did not have a healthcare visit in > 180 days were censored at their last healthcare visit. We estimated the cumulative incidence of retention using Kaplan-Meier methods considering (i) only records from a participant's ART initiation clinic (not accounting for transfers) and (ii) all records (accounting for transfers), over time and by gender. We estimated risk differences and bootstrapped 95% confidence intervals to quantify misclassification in retention estimates due to patient transfers.

RESULTS

We included 3406 PLWH initiating ART. Retention through 36 months on ART rose from 45.4% (95% CI 43.6%, 47.2%) to 54.3% (95% CI 52.4%, 56.1%) after accounting for patient transfers. Overall, 8.9% (95% CI 8.1%, 9.7%) of participants were misclassified as LTFU due to patient transfers.

CONCLUSIONS

Patient transfers can appreciably bias estimates of retention in HIV care. Electronic medical records can help quantify patient transfers and improve retention estimates.

Quantification of the pace of biological aging in humans through a blood test, the DunedinPoAm DNA methylation algorithm

Biological aging is the gradual, progressive decline in system integrity that occurs with advancing chronological age, causing morbidity and disability. Measurements of the pace of aging are needed as surrogate endpoints in trials of therapies designed to prevent disease by slowing biological aging. We report a blood-DNA-methylation measure that is sensitive to variation in pace of biological aging among individuals born the same year. We first modeled change-over-time in 18 biomarkers tracking organ-system integrity across 12 years of follow-up in n = 954 members of the Dunedin Study born in 1972-1973. Rates of change in each biomarker over ages 26-38 years were composited to form a measure of aging-related decline, termed Pace-of-Aging. Elastic-net regression was used to develop a DNA-methylation predictor of Pace-of-Aging, called DunedinPoAm for Dunedin(P)ace(o)f(A)ging(m)ethylation. Validation analysis in cohort studies and the CALERIE trial provide proof-of-principle for DunedinPoAm as a single-time-point measure of a person's pace of biological aging.

A diffusion-weighted imaging tract-based spatial statistics study of autism spectrum disorder in preschool-aged children

BACKGROUND

The core symptoms of autism spectrum disorder (ASD) are widely theorized to result from altered brain connectivity. Diffusion-weighted magnetic resonance imaging (DWI) has been a versatile method for investigating underlying microstructural properties of white matter (WM) in ASD. Despite phenotypic and etiological heterogeneity, DWI studies in majority male samples of older children, adolescents, and adults with ASD have largely reported findings of decreased fractional anisotropy (FA) across several commissural, projection, and association fiber tracts. However, studies in preschool-aged children (i.e., < 30-40 months) suggest individuals with ASD have increased measures of WM FA earlier in development.

METHODS

We analyzed 127 individuals with ASD (85♂, 42♀) and 54 typically developing (TD) controls (42♂, 26♀), aged 25.1-49.6 months. Voxel-wise effects of ASD diagnosis, sex, age, and their interaction on DWI measures of FA, mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) were investigated using tract-based spatial statistics (TBSS) while controlling mean absolute and relative motion.

RESULTS

Compared to TD controls, males and females with ASD had significantly increased measures of FA in eight clusters (threshold-free cluster enhancement p < 0.05) that incorporated several WM tracts including regions of the genu, body, and splenium of the corpus callosum, inferior frontal-occipital fasciculi, inferior and superior longitudinal fasciculi, middle and superior cerebellar peduncles, and corticospinal tract. A diagnosis by sex interaction was observed in measures of AD across six significant clusters incorporating areas of the body, genu, and splenium of the corpus collosum. In these tracts, females with ASD showed increased AD compared to TD females, while males with ASD showed decreased AD compared to TD males.

CONCLUSIONS

The current findings support growing evidence that preschool-aged children with ASD have atypical measures of WM microstructure that appear to differ in directionality from alterations observed in older individuals with the condition. To our knowledge, this study represents the largest sample of preschool-aged females with ASD to be evaluated using DWI. Microstructural differences associated with ASD largely overlapped between sexes. However, differential relationships of AD measures indicate that sex likely modulates ASD neuroanatomical phenotypes. Further longitudinal study is needed to confirm and quantify the developmental relationship of WM structure in ASD.

Conservation and divergence of protein pathways in the vertebrate heart

Heart disease is the leading cause of death in the western world. Attaining a mechanistic understanding of human heart development and homeostasis and the molecular basis of associated disease states relies on the use of animal models. Here, we present the cardiac proteomes of 4 model vertebrates with dual circulatory systems: the pig (Sus scrofa), the mouse (Mus musculus), and 2 frogs (Xenopus laevis and Xenopus tropicalis). Determination of which proteins and protein pathways are conserved and which have diverged within these species will aid in our ability to choose the appropriate models for determining protein function and to model human disease. We uncover mammalian- and amphibian-specific, as well as species-specific, enriched proteins and protein pathways. Among these, we find and validate an enrichment in cell-cycle–associated proteins within Xenopus laevis. To further investigate functional units within cardiac proteomes, we develop a computational approach to profile the abundance of protein complexes across species. Finally, we demonstrate the utility of these data sets for predicting appropriate model systems for studying given cardiac conditions by testing the role of Kielin/chordin-like protein (Kcp), a protein found as enriched in frog hearts compared to mammals. We establish that germ-line mutations in Kcp in Xenopus lead to valve defects and, ultimately, cardiac failure and death. Thus, integrating these findings with data on proteins responsible for cardiac disease should lead to the development of refined, species-specific models for protein function and disease states.

Comparison of cardiac proteomes across four vertebrate model systems reveals species-specific differentially enriched proteins and pathways, including the Xenopus-enriched Kielin/chordin-like protein (Kcp), which is shown to be important for proper heart development.

4.1Ba is necessary for glutamatergic synapse formation in the sensorimotor circuit of developing zebrafish

During the process of synapse formation, thousands of proteins assemble at prospective sites of cell-cell communication. Although many of these proteins have been identified, the roles they play in generating functional connections during development remain unknown. 4.1 scaffolding proteins have been implicated in synapse formation and maturation in vitro, but in vivo studies for some family members have suggested these proteins are not important for this role. We examined the role of family member 4.1B because it has been implicated in glutamatergic synaptogenesis, but has not been described in vivo. We identified two 4.1B genes in zebrafish, 4.1Ba and 4.1Bb, by sequence comparisons and synteny analysis. In situ hybridization shows these genes are differentially expressed, with 4.1Ba expressed primarily in the nervous system and 4.1Bb expressed in the nervous system and muscle, but not the spinal cord. We focused our studies on 4.1Ba in the spinal cord. 4.1Ba knockdown reduced the number of glutamatergic synapses at caudal primary motor neurons and caused an increase in the duration of touch-evoked coiling. These results suggest 4.1Ba is important for the formation of functional glutamatergic synapses in the developing zebrafish spinal cord.

A transmission-virulence evolutionary trade-off explains attenuation of HIV-1 in Uganda

Evolutionary theory hypothesizes that intermediate virulence maximizes pathogen fitness as a result of a trade-off between virulence and transmission, but empirical evidence remains scarce. We bridge this gap using data from a large and long-standing HIV-1 prospective cohort, in Uganda. We use an epidemiological-evolutionary model parameterised with this data to derive evolutionary predictions based on analysis and detailed individual-based simulations. We robustly predict stabilising selection towards a low level of virulence, and rapid attenuation of the virus. Accordingly, set-point viral load, the most common measure of virulence, has declined in the last 20 years. Our model also predicts that subtype A is slowly outcompeting subtype D, with both subtypes becoming less virulent, as observed in the data. Reduction of set-point viral loads should have resulted in a 20% reduction in incidence, and a three years extension of untreated asymptomatic infection, increasing opportunities for timely treatment of infected individuals.