Lack of tRNA-i6A modification causes mitochondrial-like metabolic deficiency in S. pombe by limiting activity of cytosolic tRNATyr, not mito-tRNA

tRNA-isopentenyl transferases (IPTases) are highly conserved enzymes that form isopentenyl-N(6)-A37 (i6A37) on subsets of tRNAs, enhancing their translation activity. Nuclear-encoded IPTases modify select cytosolic (cy-) and mitochondrial (mt-) tRNAs. Mutation in human IPTase, TRIT1, causes disease phenotypes characteristic of mitochondrial translation deficiency due to mt-tRNA dysfunction. Deletion of the Schizosaccharomyces pombe IPTase (tit1-Δ) causes slow growth in glycerol, as well as in rapamycin, an inhibitor of TOR kinase that maintains metabolic homeostasis. Schizosaccharomyces pombe IPTase modifies three different cy-tRNAs(Ser) as well as cy-tRNA(Tyr), cy-tRNA(Trp), and mt-tRNA(Trp). We show that lower ATP levels in tit1-Δ relative to tit1(+) cells are also more decreased by an inhibitor of oxidative phosphorylation, indicative of mitochondrial dysfunction. Here we asked if the tit1-Δ phenotypes are due to hypomodification of cy-tRNA or mt-tRNA. A cytosol-specific IPTase that modifies cy-tRNA, but not mt-tRNA, fully rescues the tit1-Δ phenotypes. Moreover, overexpression of cy-tRNAs also rescues the phenotypes, and cy-tRNA(Tyr) alone substantially does so. Bioinformatics indicate that cy-tRNA(Tyr) is most limiting for codon demand in tit1-Δ cells and that the cytosolic mRNAs most loaded with Tyr codons encode carbon metabolilizing enzymes, many of which are known to localize to mitochondria. Thus, S. pombe i6A37 hypomodification-associated metabolic deficiency results from hypoactivity of cy-tRNA, mostly tRNA(Tyr), and unlike human TRIT1-deficiency does not impair mitochondrial translation due to mt-tRNA hypomodification. We discuss species-specific aspects of i6A37. Specifically relevant to mitochondria, we show that its hypermodified version, ms2i6A37 (2-methylthiolated), which occurs on certain mammalian mt-tRNAs (but not cy-tRNAs), is not found in yeast.

Distinct mechanisms of inadequate erythropoiesis induced by tumor necrosis factor alpha or malarial pigment

The role of infection in erythropoietic dysfunction is poorly understood. In children with P. falciparum malaria, the by-product of hemoglobin digestion in infected red cells (hemozoin) is associated with the severity of anemia which is independent of circulating levels of the inflammatory cytokine tumor necrosis alpha (TNF-α). To gain insight into the common and specific effects of TNF-α and hemozoin on erythropoiesis, we studied the gene expression profile of purified primary erythroid cultures exposed to either TNF-α (10ng/ml) or to hemozoin (12.5μg/ml heme units) for 24 hours. Perturbed gene function was assessed using co-annotation of associated gene ontologies and expression of selected genes representative of the profile observed was confirmed by real time PCR (rtPCR). The changes in gene expression induced by each agent were largely distinct; many of the genes significantly modulated by TNF-α were not affected by hemozoin. The genes modulated by TNF-α were significantly enriched for those encoding proteins involved in the control of type 1 interferon signalling and the immune response to viral infection. In contrast, genes induced by hemozoin were significantly enriched for functional roles in regulation of transcription and apoptosis. Further analyses by rtPCR revealed that hemozoin increases expression of transcription factors that form part of the integrated stress response which is accompanied by reduced expression of genes involved in DNA repair. This study confirms that hemozoin induces cellular stress on erythroblasts that is additional to and distinct from responses to inflammatory cytokines and identifies new genes that may be involved in the pathogenesis of severe malarial anemia. More generally the respective transcription profiles highlight the varied mechanisms through which erythropoiesis may be disrupted during infectious disease.

A population-based longitudinal study of childhood neurodevelopmental disorders, IQ and subsequent risk of psychotic experiences in adolescence

BACKGROUND

Schizophrenia has a neurodevelopmental component to its origin, and may share overlapping pathogenic mechanisms with childhood neurodevelopmental disorders (NDs). Nevertheless, longitudinal studies of psychotic outcomes among individuals with NDs are limited. We report a population-based prospective study of six common childhood NDs, subsequent neurocognitive performance and the risk of psychotic experiences (PEs) in early adolescence.

METHOD

PEs were assessed by semi-structured interviews at age 13 years. IQ and working memory were measured between ages 9 and 11 years. The presence of six NDs (autism spectrum, dyslexia, dyspraxia, dysgraphia, dysorthographia, dyscalculia) was determined from parent-completed questionnaires at age 9 years. Linear regression calculated the mean difference in cognitive scores between children with and without NDs. Associations between NDs and PEs were expressed as odds ratios (ORs) with 95% confidence intervals (CIs); effects of cognitive deficits were examined. Potential confounders included age, gender, father's social class, ethnicity and maternal education.

RESULTS

Out of 8220 children, 487 (5.9%) were reported to have NDs at age 9 years. Children with, compared with those without, NDs performed worse on all cognitive measures; the adjusted mean difference in total IQ was 6.84 (95% CI 5.00-8.69). The association between total IQ and NDs was linear (p < 0.0001). The risk of PEs was higher in those with, compared with those without, NDs; the adjusted OR for definite PEs was 1.76 (95% CI 1.11-2.79). IQ (but not working memory) deficit partly explained this association.

CONCLUSIONS

Higher risk of PEs in early adolescence among individuals with childhood ND is consistent with the neurodevelopmental hypothesis of schizophrenia.

Metastasis dormancy in estrogen receptor-positive breast cancer

About 20% to 40% of patients with breast cancer eventually develop recurrences in distant organs, which are often not detected until years to decades after the primary tumor diagnosis. This phenomenon is especially pronounced in estrogen receptor-positive (ER(+)) breast cancer, suggesting that ER(+) cancer cells may stay dormant for a protracted period of time, despite adjuvant therapies. Multiple mechanisms have been proposed to explain how cancer cells survive and remain in dormancy, and how they become reactivated and exit dormancy. These mechanisms include angiogenic switch, immunosurveillance, and interaction with extracellular matrix and stromal cells. How to eradicate or suppress these dormant cancer cells remains a major clinical issue because of the lack of knowledge about the biologic and clinical nature of these cells. Herein, we review the clinical manifestation of metastasis dormancy in ER(+) tumors, the current biologic insights regarding tumor dormancy obtained from various experimental models, and the clinical challenges to predict, detect, and treat dormant metastases. We also discuss future research directions toward a better understanding of the biologic mechanisms and clinical management of ER(+) dormant metastasis.

The Identification of Seniors at Risk (ISAR) score to predict clinical outcomes and health service costs in older people discharged from UK acute medical units

BACKGROUND

tools are required to identify high-risk older people in acute emergency settings so that appropriate services can be directed towards them.

OBJECTIVE

to evaluate whether the Identification of Seniors At Risk (ISAR) predicts the clinical outcomes and health and social services costs of older people discharged from acute medical units.

DESIGN

an observational cohort study using receiver-operator curve analysis to compare baseline ISAR to an adverse clinical outcome at 90 days (where an adverse outcome was any of death, institutionalisation, hospital readmission, increased dependency in activities of daily living (decrease of 2 or more points on the Barthel ADL Index), reduced mental well-being (increase of 2 or more points on the 12-point General Health Questionnaire) or reduced quality of life (reduction in the EuroQol-5D) and high health and social services costs over 90 days estimated from routine electronic service records.

SETTING

two acute medical units in the East Midlands, UK.

PARTICIPANTS

a total of 667 patients aged ≥70 discharged from acute medical units.

RESULTS

an adverse outcome at 90 days was observed in 76% of participants. The ISAR was poor at predicting adverse outcomes (AUC: 0.60, 95% CI: 0.54-0.65) and fair for health and social care costs (AUC: 0.70, 95% CI: 0.59-0.81).

CONCLUSIONS

adverse outcomes are common in older people discharged from acute medical units in the UK; the poor predictive ability of the ISAR in older people discharged from acute medical units makes it unsuitable as a sole tool in clinical decision-making.

Completeness of maternal smoking status recording during pregnancy in United Kingdom primary care data

BACKGROUND

Given the health impacts of smoking during pregnancy and the opportunity for primary healthcare teams to encourage pregnant smokers to quit, our primary aim was to assess the completeness of gestational smoking status recording in primary care data and investigate whether completeness varied with women's characteristics. As a secondary aim we assessed whether completeness of recording varied before and after the introduction of the Quality and Outcomes Framework (QOF).

METHODS

In The Health Improvement Network (THIN) database we calculated the proportion of pregnancies ending in live births or stillbirths where there was a recording of maternal smoking status for each year from 2000 to 2009. Logistic regression was used to assess variation in the completeness of maternal smoking recording by maternal characteristics, before and after the introduction of QOF.

RESULTS

Women had a record of smoking status during the gestational period in 28% of the 277,552 pregnancies identified. In 2000, smoking status was recorded in 9% of pregnancies, rising to 43% in 2009. Pregnant women from the most deprived group were 17% more likely to have their smoking status recorded than pregnant women from the least deprived group before QOF implementation (OR 1.17, 95% CI 1.10-1.25) and 42% more likely afterwards (OR 1.42, 95% CI 1.37-1.47). A diagnosis of asthma was related to recording of smoking status during pregnancy in both the pre-QOF (OR 1.63, 95% CI 1.53-1.74) and post-QOF periods (OR 2.08, 95% CI 2.02-2.15). There was no association between having a diagnosis of diabetes and recording of smoking status during pregnancy pre-QOF however, post-QOF diagnosis of diabetes was associated with a 12% increase in recording of smoking status (OR 1.12, 95% CI 1.05-1.19).

CONCLUSION

Recording of smoking status during pregnancy in primary care data is incomplete though has improved over time, especially after the implementation of the QOF, and varies by maternal characteristics and QOF-incentivised morbidities.

Understanding skin care and skin barrier function in infants

Skin care practices involving the application of products to the skin are common. This article focuses on these aspects of infant skin care, the importance of skin barrier function and how the use of products and therapies applied to the skin can affect skin‑barrier function. It also challenges current practice and tradition, and highlights the evolving body of research into practice and tradition.

Care in specialist medical and mental health unit compared with standard care for older people with cognitive impairment admitted to general hospital: randomised controlled trial (NIHR TEAM trial)

OBJECTIVE

To develop and evaluate a best practice model of general hospital acute medical care for older people with cognitive impairment.

DESIGN

Randomised controlled trial, adapted to take account of constraints imposed by a busy acute medical admission system.

SETTING

Large acute general hospital in the United Kingdom.

PARTICIPANTS

600 patients aged over 65 admitted for acute medical care, identified as "confused" on admission.

INTERVENTIONS

Participants were randomised to a specialist medical and mental health unit, designed to deliver best practice care for people with delirium or dementia, or to standard care (acute geriatric or general medical wards). Features of the specialist unit included joint staffing by medical and mental health professionals; enhanced staff training in delirium, dementia, and person centred dementia care; provision of organised purposeful activity; environmental modification to meet the needs of those with cognitive impairment; delirium prevention; and a proactive and inclusive approach to family carers.

PRIMARY OUTCOME

number of days spent at home over the 90 days after randomisation.

SECONDARY OUTCOMES

structured non-participant observations to ascertain patients' experiences; satisfaction of family carers with hospital care. When possible, outcome assessment was blind to allocation.

RESULTS

There was no significant difference in days spent at home between the specialist unit and standard care groups (median 51 v 45 days, 95% confidence interval for difference -12 to 24; P=0.3). Median index hospital stay was 11 versus 11 days, mortality 22% versus 25% (-9% to 4%), readmission 32% versus 35% (-10% to 5%), and new admission to care home 20% versus 28% (-16% to 0) for the specialist unit and standard care groups, respectively. Patients returning home spent a median of 70.5 versus 71.0 days at home (-6.0 to 6.5). Patients on the specialist unit spent significantly more time with positive mood or engagement (79% v 68%, 2% to 20%; P=0.03) and experienced more staff interactions that met emotional and psychological needs (median 4 v 1 per observation; P<0.001). More family carers were satisfied with care (overall 91% v 83%, 2% to 15%; P=0.004), and severe dissatisfaction was reduced (5% v 10%, -10% to 0%; P=0.05).

CONCLUSIONS

Specialist care for people with delirium and dementia improved the experience of patients and satisfaction of carers, but there were no convincing benefits in health status or service use. Patients' experience and carers' satisfaction might be more appropriate measures of success for frail older people approaching the end of life.

TRIAL REGISTRATION

Clinical Trials NCT01136148.

Sex-stratified genome-wide association studies including 270,000 individuals show sexual dimorphism in genetic loci for anthropometric traits

Given the anthropometric differences between men and women and previous evidence of sex-difference in genetic effects, we conducted a genome-wide search for sexually dimorphic associations with height, weight, body mass index, waist circumference, hip circumference, and waist-to-hip-ratio (133,723 individuals) and took forward 348 SNPs into follow-up (additional 137,052 individuals) in a total of 94 studies. Seven loci displayed significant sex-difference (FDR<5%), including four previously established (near GRB14/COBLL1, LYPLAL1/SLC30A10, VEGFA, ADAMTS9) and three novel anthropometric trait loci (near MAP3K1, HSD17B4, PPARG), all of which were genome-wide significant in women (P<5×10(-8)), but not in men. Sex-differences were apparent only for waist phenotypes, not for height, weight, BMI, or hip circumference. Moreover, we found no evidence for genetic effects with opposite directions in men versus women. The PPARG locus is of specific interest due to its role in diabetes genetics and therapy. Our results demonstrate the value of sex-specific GWAS to unravel the sexually dimorphic genetic underpinning of complex traits.

Stress in Latino families following an adolescent's childbearing: effects on family relationships and siblings

This study examined how increased stress in Latino families following an adolescent's childbearing impacts family relationships and the adolescent's siblings. Participants were 243 Mexican American youth (mean age: 13.7 years; 62% girls), or 121 youth who had a pregnant adolescent sister and 122 youth who had an adolescent sister who had never been pregnant. Youth and their mothers were studied at 4 time points across 15 months: The families of pregnant adolescents were studied when the adolescent sister was in her third trimester of pregnancy, and at 2 months, 6 months, and 12 months postpartum; the families of never-pregnant adolescents were studied at like intervals. Individual fixed-effects structural equation models were computed, which control for earlier measures of study constructs and thereby reduce omitted variable bias from preexisting family group differences. Results showed that an adolescent's childbearing was related to increases in family stress, which were related to increases in mothers' harsh parenting and mother-sibling conflict, which, in turn, were related to subsequent increases in siblings' problem behavior. Multiple group analyses revealed that the pathways through which a teenager's childbearing influences siblings operate similarly for girls and boys. Tests of an alternate ordering of model variables indicated a poor fit with the data. Findings provide evidence that the accumulation of stressful family changes following an adolescent's childbearing can negatively impact siblings. Findings also elucidate how family-level stress and disruption experienced across a family transition trickle down to affect family relationships and, in turn, child family members.

The younger siblings of childbearing adolescents: parenting influences on their academic and social-emotional adjustment

The younger siblings of childbearing adolescents have poorer school outcomes and exhibit more internalizing and externalizing problems compared to their peers without a childbearing sister. We test a model where living with an adolescent childbearing sister constitutes a major family stressor that disrupts mothers' parenting and well-being, and through which, adversely affect youths' adjustment. Data came from 243 Latino younger siblings (62% female, M age 13.7 years) and their mothers, 121 of whom lived with a childbearing adolescent sister and 122 of whom did not. Individual fixed-effects models controlled for earlier measures of each respective model construct, thereby reducing omitted variable bias from pre-existing group differences. Results show that, for boys, the relationship between living with a childbearing adolescent sister and youth outcomes was sequentially mediated through mothers' stress and parenting (i.e., monitoring and nurturance). For girls, however, the relationship was mediated through mothers' monitoring only. Findings elucidate the within-family processes that contribute to the problematic outcomes of youth living with childbearing adolescent older sisters.

The impact of motor and non motor symptoms on health state values in newly diagnosed idiopathic Parkinson's disease

The aim of the study was to estimate health state utility values in newly diagnosed idiopathic Parkinson's disease (PD) for use in the assessment of health-related quality-of-life (HRQL), and in the estimation of quality-adjusted life-years (QALYs). Data from 162 patients enrolled in a community-based incidence study of PD were used to estimate health state utility values. Self-report data from the EQ-5D, a generic measure of HRQL, were used to derive preference-based health state utility values. The impact of motor and non motor symptoms, and other clinical and demographic factors, on the derived EQ-5D health state values was examined in univariate and multivariate analyses. The mean health state utility value for recently diagnosed PD patients was estimated at 0.65 ± 0.27. Significant reductions in health state values were attributable to pain (-0.18), motor functioning (-0.16), depression (-0.12), and insomnia (-0.11). Depression had its greatest impact (-0.19) in patients in the less severe stages of PD (i.e. Hoehn Yahr stages ≤2.5). This study shows, through the presentation of QALY values, that there is scope to achieve significant health gains in newly diagnosed idiopathic PD patients via improved management of pain, depression and insomnia, alongside the treatment of primary motor symptoms.

Maternal mental health and its association with infant growth at 6 months in ethnic groups: results from the Born-in-Bradford birth cohort study

Objective

To identify factors associated with infant growth up to 6 months, with a particular focus on maternal distress, and to explore the effect of ethnicity on any relation between maternal distress and infant growth.

Methods

Cohort study recruiting White and Pakistani women in the United Kingdom (UK). Infant growth was measured at birth and 6 months. Standard assessment of mental health (GHQ-28) was undertaken in pregnancy (26–28 weeks gestation) and 6 months postpartum. Modelling included social deprivation, ethnicity, and other known influences on infant growth such as maternal smoking and alcohol consumption.

Results

Maternal distress improved markedly from pregnancy to 6 months postpartum. At both times Pakistani women had more somatic and depression symptoms than White women. Depression in pregnancy (GHQ subscale D) was associated with lower infant growth at 6 months. Self-reported social dysfunction in pregnancy (GHQ subscale C) was associated with lower gestational age.. Pakistani women reported higher GHQ scores during pregnancy associated with smaller infants at birth. They lived in areas of higher social deprivation, reported less alcohol consumption and smoking postnatally, all independent influences on growth at 6 months.

Conclusions

Maternal mental health in pregnancy is an independent influence on infant growth up to 6 months and is associated with ethnicity which was itself associated with deprivation in our sample. There is a complex relationship between symptoms of maternal distress, ethnicity, deprivation, health behaviours, and early infant growth. Measures should include both emotional and somatic symptoms and interventions to reduce risks of poor early growth need to include psychological and social components.

The risk of preeclampsia rises with increasing prepregnancy body mass index

PURPOSE

To explore the dose-dependent relation between prepregnancy body mass index (BMI) and the risk of preeclampsia after adjusting for measured confounders.

METHODS

We studied 1179 primiparous women who enrolled at < 16 weeks' gestation into a prospective cohort study of the pathogenesis of preeclampsia. Multivariable logistic regression was used to quantify the independent effect of prepregnancy BMI on the risk of preeclampsia after adjusting for race and smoking status. BMI was specified as a restricted quadratic spline.

RESULTS

Preeclampsia risk rose strikingly from a BMI of 15 to 30 kg/m(2). Compared with women with a BMI of 21, the adjusted risk of preeclampsia doubled at a BMI of 26 (odds ratio 2.1 [95% confidence interval, 1.4, 3.4]), and nearly tripled at a BMI of 30 (2.9 [1.6, 5.3]). Women with a BMI of 17 had a 57% reduction in preeclampsia risk compared with women with a BMI of 21 (0.43 [0.25, 0.76]), and a BMI of 19 was associated with a 33% reduction in risk (0.66 [0.50, 0.87]).

CONCLUSIONS

These results indicate that preeclampsia risk rises through most of the BMI distribution. The dramatic elevation in overweight prevalence in the United States may increase preeclampsia incidence in the future.