Selective degradation of cyclin B1 mRNA in rat oocytes by RNA interference (RNAi)

Cyclic adenosine monophosphate (cAMP) keeps oocytes in meiotic arrest, thereby preventing activation of the key regulators of meiosis, p34cdc2/cyclin B1, (known as maturation-promoting factor (MPF)) and Erk 1 and 2, members of the mitogen-activated protein kinase (MAPK) family. The activity of MAPK in oocytes is upregulated by Mos. We previously demonstrated that Mos translation in rat oocytes is negatively regulated by a PKA-mediated cAMP action, which inhibits c-mos mRNA polyadenylation and is associated with the suppression of p34 cdc2 kinase. The goal of the present study was to provide definitive evidence that Mos translation is subjected to MPF regulation. In order to inhibit MPF activity, we employed the double-stranded (ds) RNA interference (RNAi) of gene expression. We demonstrated that the introduction of cyclin B1 dsRNA into rat oocytes selectively depleted the corresponding mRNA, further ablating its protein product. These oocytes, which exhibit low MPF activity, failed to elongate the c-mos mRNA poly(A) tail, did not accumulate Mos and were unable to activate MAPK. We conclude that an active MPF in rat oocytes is necessary for c-mos mRNA polyadenylation and Mos translation.     

Detection and phasing of single base de novo mutations in biopsies from human in vitro fertilized embryos by advanced whole-genome sequencing

Currently, the methods available for preimplantation genetic diagnosis (PGD) of in vitro fertilized (IVF) embryos do not detect de novo single-nucleotide and short indel mutations, which have been shown to cause a large fraction of genetic diseases. Detection of all these types of mutations requires whole-genome sequencing (WGS). In this study, advanced massively parallel WGS was performed on three 5- to 10-cell biopsies from two blastocyst-stage embryos. Both parents and paternal grandparents were also analyzed to allow for accurate measurements of false-positive and false-negative error rates. Overall, >95% of each genome was called. In the embryos, experimentally derived haplotypes and barcoded read data were used to detect and phase up to 82% of de novo single base mutations with a false-positive rate of about one error per Gb, resulting in fewer than 10 such errors per embryo. This represents a ∼100-fold lower error rate than previously published from 10 cells, and it is the first demonstration that advanced WGS can be used to accurately identify these de novo mutations in spite of the thousands of false-positive errors introduced by the extensive DNA amplification required for deep sequencing. Using haplotype information, we also demonstrate how small de novo deletions could be detected. These results suggest that phased WGS using barcoded DNA could be used in the future as part of the PGD process to maximize comprehensiveness in detecting disease-causing mutations and to reduce the incidence of genetic diseases.Worldwide, more than 5 million babies (Ferraretti et al. 2013) have been born through in vitro fertilization (IVF) since the birth of the first in 1978 (Steptoe and Edwards 1978). Exact numbers are difficult to determine, but it has been estimated that currently 350,000 babies are born yearly through IVF (de Mouzon et al. 2009, 2012; Centers for Disease Control and Prevention 2011; Ferraretti et al. 2013). That number is expected to rise, as advanced maternal age is associated with decreased fertility rates and women in developed countries continue to delay childbirth to later ages. In 95% of IVF procedures, no diagnostic testing of the embryos is performed (https://www.sartcorsonline.com/rptCSR_PublicMultYear.aspx?ClinicPKID=0). Couples with prior difficulties conceiving or those wishing to avoid the transmission of highly penetrant heritable diseases often choose to perform preimplantation genetic diagnosis (PGD). PGD involves the biopsy of one cell from a 3-d embryo or the recently more preferred method, due to improved implantation success rates (Scott et al. 2013b), of up to 10 cells from a 5- to 6-d blastocyst-stage embryo. Following biopsy, genetic analysis is performed on the isolated cell(s). Currently this is an assay for translocations and the correct chromosome copy number (Hodes-Wertz et al. 2012; Munne 2012; Yang et al. 2012; Scott et al. 2013a; Yin et al. 2013), a unique test designed and validated for each specific heritable disease (Gutierrez-Mateo et al. 2009), or a combination of both (Treff et al. 2013). Importantly, none of these approaches can detect de novo mutations.Advanced maternal age has long been associated with an increased risk of producing aneuploid embryos (Munne et al. 1995; Crow 2000; Hassold and Hunt 2009) and giving birth to a child afflicted with Down syndrome or other diseases resulting from chromosomal copy number alterations. Conversely, children of older fathers have been shown to have an increase in single base and short multibase insertion/deletion (indels) de novo mutations (Kong et al. 2012). Many recent large-scale sequencing studies have found that de novo variations spread across many different genes are likely to be the cause of a large fraction of autism cases (Michaelson et al. 2012; O’Roak et al. 2012; Sanders et al. 2012; De Rubeis et al. 2014; Iossifov et al. 2014), severe intellectual disability (Gilissen et al. 2014), epileptic encephalopathies (Epi4K Consortium and Epilepsy Phenome/Genome Project 2013), and many other congenital disorders (de Ligt et al. 2012; Veltman and Brunner 2012; Yang et al. 2013; Al Turki et al. 2014). Additionally rare and de novo variations have been suggested to be prevalent in patients with schizophrenia (Fromer et al. 2014; Purcell et al. 2014), and Michaelson et al. (2012) found that single base de novo mutations affect conserved regions of the genome and essential genes more often than regions of unknown function. Current targeted approaches to PGD would miss many of these important functional changes within the embryonic DNA sequence, and even a whole-genome sequencing (WGS)–based carrier screen of both parents would not enable comprehensive preimplantation or prenatal diagnoses due to de novo mutations. As more parents delay childbirth into their mid-30s and later, these studies suggest we should try to provide better diagnostic tests for improving the health of newborns. In this study, we demonstrate the use of an advanced WGS process that provides an accurate and phased genome sequence from about 10 cells, allowing highly sensitive and specific detection of single base de novo mutations from IVF blastocyst biopsies.     

Myocardial healing using cardiac fat

Introduction: Chronic diseases, including myocardial scar healing and heart failure remission, impose huge social and economic burdens, and novel approaches are needed. Several therapeutic modalities are currently being evaluated, including cell therapy, stem cell conditioning, and cardiac tissue engineering.

Areas covered: This review discusses the restoration of cardiac function after myocardial infarction using a vascularized flap of autologous cardiac adipose tissue over an akinetic scar. It addresses the risks and benefits of using cardiac adipose progenitors and the adipose graft transposition procedure (AGTP) to ameliorate cardiac dysfunction in preclinical and clinical trials.

Expert commentary: The focus is shifting from first-generation studies that used ex vivo expanded and manipulated progenitors to newer second-generation approaches, including AGTP, which are inexpensive and do not raise ethical issues. AGTP safety has been validated, and the ongoing AGTP-2 trial to determine AGTP efficacy and outcome is currently recruiting patients (NCT02798276). This reparative strategy is safe, avoids the risks associated with ex vivo manipulation, and the preclinical and clinical trials performed to date show cardiac function recovery and reduced necrosis. Confirmation of these data in the AGTP-2 trial could pave the way for the clinical use of this novel modality.     

Profiles of Food Security for US Farmworker Households and Factors Related to Dynamic of Change

Objectives. We recruited 248 farmworker families with preschool-aged children in North Carolina and examined food security indicators over 24 months to identify food security patterns and examine the dynamic of change over time.Methods. Participants in the Niños Sanos study, conducted 2011 to 2014, completed quarterly food security assessments. Based on responses to items in the US Household Food Security Survey Module, we identified different states of food security by using hidden Markov model analysis, and examined factors associated with different states. We delineated factors associated with changes in state by using mixed-effect ordinal logistic regression.Results. About half of the households (51%) consistently stayed in the most food-secure state. The least food-secure state was transient, with only 29% probability of this state for 2 consecutive quarters. Seasonal (vs migrant) work status, having immigration documents (vs not documented), and season predicted higher levels of food security.Conclusions. Heterogeneity in food security among farmworker households calls for tailoring intervention strategies. The transiency and unpredictability of low food security suggest that access to safety-net programs could reduce low food security risk in this population.Farmworkers in the United States experience challenging living conditions and economic insecurity because of low-paying and contingent employment. Although an exact number of farmworkers is not available, estimates place the population at 900 000, plus dependents.1 This includes migrant farmworkers, who establish temporary residences to do farm work, as well as seasonal workers who reside in one place and do farm work during the agricultural season.2 Currently, most farmworkers are Latino and foreign-born,3 which can limit their eligibility and access to food safety-net programs such as the Supplemental Nutrition Assistance Program. In addition, many reside in rural areas where access to healthy food retail stores may be limited by both availability and transportation, although home food production is sometimes possible.4 Together, these create a situation in which farmworker households are likely to experience low food security (resulting from insufficient household resources), but this may be episodic. Children in farmworker households may be particularly vulnerable to the effects of low food security.5Low food security is associated with negative developmental outcomes in infants and toddlers.6 Persistently low food security in early childhood is associated with long-term lower health status.7 For children at school age, this can adversely affect academic performance, weight gain, and social skills.8 With the large population of farmworkers in the United States, food security among their families is an important public health issue.Previous reports of food security for farmworker households have found 20% to 80% to be food insecure.9–14 However, all of these reports have been cross-sectional, and most have used an extended recall period, asking respondents to recall whether their household was food insecure at any time during the past year. Such data provide no information on the duration of food security states or on factors associated with transitions in and out of low food security. Examining food security over time as a dynamic construct is necessary to understand its duration and to develop protective measures for low food security.This repeated-measures study gathered data quarterly for 24 months, and examined different states of food security by using the 18-item US Household Food Security Survey Module.15 Instead of constructing a single score, we used the full item set to form a food security profile. The approach allowed us to delineate several different states of food security within the food security profile, and examine the dynamic of change in food security over the 24-month period. The aims of the study were to (1) describe multiple states of food security of farmworker households, (2) identify factors associated with the different food security states, and (3) delineate the dynamic of change in food security states across a period of 24 months.     

Association between overweight and characteristics of young adult students: support for nursing care

OBJECTIVE:

to verify associations between overweight and the characteristics of young adult students to support nursing care.

METHOD:

case-control study conducted with young adults from public schools. The sample was composed of 441 participants (147 cases and 294 controls, with and without excess weight, respectively). Sociodemographic and clinical characteristics were collected together with exposure factors and anthropometrics. Multiple logistic regression was used. The study received Institutional Review Board approval.

RESULTS:

statistically significant association with overweight: non-Caucasian, having a partner; weight gain during adolescence, mother''s excess weight, the use of obesogenic medication, augmented diastolic blood pressure, of abdominal circumference and waist/hip ratio. In addition to these, schooling and weight gain during childhood were also included in the multivariate analysis. After adjustment, the final model included: having a partner, weight gain during adolescence, augmented diastolic blood pressure and abdominal circumference.

CONCLUSION:

the analysis of predictor variables for excess weight among young adult students supports nurses in planning and developing educational practices aimed to prevent this clinical condition, which is a risk factor for other chronic comorbidities, such as cardiovascular diseases.     

Correction: Tunnel injection from WS2 quantum dots to InGaN/GaN quantum wells

Correction for ‘Tunnel injection from WS₂ quantum dots to InGaN/GaN quantum wells’ by Svette Reina Merden Santiago et al., RSC Adv., 2018, 8, 15399–15404.

Eqn (4) in the published paper was incorrect; the correct version is shown below:4The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.