281 research outputs found

    Bta-miR-10b secreted by bovine embryos negatively impacts preimplantation embryo quality

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    In a previous study, we found miR-10b to be more abundant in a conditioned culture medium of degenerate embryos compared to that of blastocysts. Here, we show that miR-10b mimics added to the culture medium can be taken up by embryos. This uptake results in an increase in embryonic cell apoptosis and aberrant expression of DNA methyltransferases (DNMTs). Using several algorithms, Homeobox Al (HOXA1) was identified as one of the potential miR-10b target genes and dual-luciferase assay confirmed HOXA1 as a direct target of miR-10b. Microinjection of si-HOXA1 into embryos also resulted in an increase in embryonic cell apoptosis and downregulation of DNMTs. Cell progression analysis using Madin-Darby bovine kidney cells (MDBKs) showed that miR-10b overexpression and HOXA1 knockdown results in suppressed cell cycle progression and decreased cell viability. Overall, this work demonstrates that miR-10b negatively influences embryo quality and might do this through targeting HOXA1 and/or influencing DNA methylation

    Quasi-dynamic network loading: Adding queuing and spillback to static traffic assignment

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    For many years, static traffic assignment models have been widely applied in transport planning studies and will continue to be an important tool for strategic policy decisions. As is well known, in the traditional approach, the location of the delays and queues are not predicted correctly, and the resulting travel times do not correspond well with reality. Dynamic models can approach reality much better, but come at a computational cost. In this paper we propose a quasi-dynamic model which inherits most of the computational efficiency of static models, but aims to keep most of the important dynamic features, such as queuing, spillback, and shockwaves. Instead of adjusting the traditional static model or using heuristics, we theoretically derive the model from the dynamic link transmission model, assuming stationary travel demand and instantaneous flow. Furthermore, we present algorithms for solving the model. On a corridor network we illustrate the feasibility and compare it with other approaches, and on a larger network of Amsterdam we discuss the computational efficiency

    Bias in regression coefficient estimates when assumptions for handling missing data are violated: a simulation study

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    Background The purpose of this simulation study is to assess the performance of multiple imputation compared to complete case analysis when assumptions of missing data mechanisms are violated. Methods The authors performed a stochastic simulation study to assess the performance of Complete Case (CC) analysis and Multiple Imputation (MI) with different missing data mechanisms (missing completely at random (MCAR), at random (MAR), and not at random (MNAR)). The study focused on the point estimation of regression coefficients and standard errors. Results When data were MAR conditional on Y, CC analysis resulted in biased regression coefficients; they were all underestimated in our scenarios. In these scenarios, analysis after MI gave correct estimates. Yet, in case of MNAR MI yielded biased regression coefficients, while CC analysis performed well.Conclusion The authors demonstrated that MI was only superior to CC analysis in case of MCAR or MAR. In some scenarios CC may be superior over MI. Often it is not feasible to identify the reason why data in a given dataset are missing. Therefore, emphasis should be put on reporting the extent of missing values, the method used to address them, and the assumptions that were made about the mechanism that caused missing data

    Imbalanced Folate and Vitamin B12 in the Third Trimester of Pregnancy and its Association with Birthweight and Child Growth up to 2 Years

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    Scope: Folic acid supplementation during pregnancy may lead to an imbalance when vitamin B12 intake is low (folate trap) and may affect child’s growth. Methods: The authors study the association between third trimester maternal intakes of folate and B12 and birthweight and postnatal growth of 2632 infants from the KOALA Birth Cohort Study. Plasma vitamin biomarkers are measured in 1219 women. Results: Imbalanced total intakes (folate > 430 µg day−1 combined with B12 < 5.5 µg day−1) are not associated with birthweight [ adj (95% CI) = –14.87 (–68.87, 39.13)] compared with high intakes of both. Imbalanced intake is associated with a lower z score of weight at 1–2 years [ adj = –0.14 (–0.25, –0.03)]. Having red blood cell folate > 745 nmol L−1 and plasma B12 < 172 pmol L−1 is not associated with birthweight [ adj = –7.10 (–97.90, 83.71) g]. Maternal dietary B12 intake [ adj = –9.5 (–15.6, –3.3)] and plasma methylmalonic acid [ adj = 234 (43, 426)] are associated with birthweight. Conclusion: Low maternal dietary B12 intake and elevated methylmalonic acid rather than imbalanced vitamins are associated with higher birthweight, suggesting that low maternal B12 can predispose the infants for later obesity

    Maternal recognition of pregnancy in the horse : are MicroRNAs the secret messengers?

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    The signal for maternal recognition of pregnancy (MRP) has still not been identified in the horse. High-throughput molecular biology at the embryo-maternal interface has substantially contributed to the knowledge on pathways affected during MRP, but an integrated study in which proteomics, transcriptomics and miRNA expression can be linked directly is currently lacking. The aim of this study was to provide such analysis. Endometrial biopsies, uterine fluid, embryonic tissues, and yolk sac fluid were collected 13 days after ovulation during pregnant and control cycles from the same mares. Micro-RNA-Sequencing was performed on all collected samples, mRNA-Sequencing on the same tissue samples and mass spectrometry was conducted previously on the same fluid samples. Differential expression of miRNA, mRNA and proteins showed high conformity with literature and confirmed involvement in pregnancy establishment, embryo quality, steroid synthesis and prostaglandin regulation, but the link between differential miRNAs and their targets was limited and did not indicate the identity of an unequivocal signal for MRP in the horse. Differential expression at the embryo-maternal interface was prominent, highlighting a potential role of miRNAs in embryo-maternal communication during early pregnancy in the horse. These data provide a strong basis for future targeted studies

    Selection of reference genes for quantitative real-time PCR in equine in vivo and fresh and frozen-thawed in vitro blastocysts

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    <p>Abstract</p> <p>Background</p> <p>Application of reverse transcription quantitative real-time polymerase chain reaction is very well suited to reveal differences in gene expression between <it>in vivo </it>and <it>in vitro </it>produced embryos. Ultimately, this may lead to optimized equine assisted reproductive techniques. However, for a correct interpretation of the real-time PCR results, all data must be normalized, which is most reliably achieved by calculating the geometric mean of the most stable reference genes. In this study a set of reliable reference genes was identified for equine <it>in vivo </it>and fresh and frozen-thawed <it>in vitro </it>embryos.</p> <p>Findings</p> <p>The expression stability of 8 candidate reference genes (<it>ACTB</it>, <it>GAPDH</it>, <it>H2A/I</it>, <it>HPRT1</it>, <it>RPL32</it>, <it>SDHA</it>, <it>TUBA4A</it>, <it>UBC</it>) was determined in 3 populations of equine blastocysts (fresh <it>in vivo</it>, fresh and frozen-thawed <it>in vitro </it>embryos). Application of geNorm indicated <it>UBC</it>, <it>GAPDH</it>, <it>ACTB </it>and <it>HPRT1 </it>as the most stable genes in the <it>in vivo </it>embryos and <it>UBC</it>, <it>RPL32</it>, <it>GAPDH </it>and <it>ACTB </it>in both <it>in vitro </it>populations. When <it>in vivo </it>and <it>in vitro </it>embryos were combined, <it>UBC</it>, <it>ACTB</it>, <it>RPL32 </it>and <it>GAPDH </it>were found to be the most stable. <it>SDHA </it>and <it>H2A/I </it>appeared to be highly regulated.</p> <p>Conclusions</p> <p>Based on these results, the geometric mean of <it>UBC</it>, <it>ACTB</it>, <it>RPL32 </it>and <it>GAPDH </it>is to be recommended for accurate normalization of quantitative real-time PCR data in equine <it>in vivo </it>and <it>in vitro </it>produced blastocysts.</p

    Proteins involved in embryo-maternal interaction around the signalling of maternal recognition of pregnancy in the horse

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    During maternal recognition of pregnancy (MRP), a conceptus-derived signal leads to the persistence of the corpus luteum and the maintenance of gestation. In the horse, the nature of this signal remains to be elucidated. Several studies have focused on the changes in gene expression during MRP, but little information exists at the protein level. The aim of this study was to identify the proteins at the embryo-maternal interface around signalling of MRP in the horse (day 13) by means of mass spectrometry. A distinct influence of pregnancy was established, with 119 proteins differentially expressed in the uterine fluid of pregnant mares compared to cyclic mares and with upregulation of several inhibitors of the prostaglandin synthesis during pregnancy. By creating an overview of the proteins at the embryo-maternal interface in the horse, this study provides a solid foundation for further targeted studies of proteins potentially involved in embryo-maternal interactions, MRP and pregnancy loss in the horse

    Nationwide implementation of a decision aid on vaginal birth after cesarean:a before and after cohort study

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    Woman with a history of a previous cesarean section (CS) can choose between an elective repeat CS (ERCS) and a trial of labor (TOL), which can end in a vaginal birth after cesarean (VBAC) or an unplanned CS. Guidelines describe women's rights to make an informed decision between an ERCS or a TOL. However, the rates of TOL and vaginal birth after CS varies greatly between and within countries. The objective of this study is to asses nation-wide implementation of counselling with a decision aid (DA) including a prediction model, on intended delivery compared to care as usual. We hypothesize that this may result in a reduction in practice variation without an increase in cesarean rates or complications. In a multicenter controlled before and after cohort study we evaluate the effect of nation-wide implementation of a DA. Practice variation was defined as the standard deviation (SD) of TOL percentages. A total of 27 hospitals and 1,364 women were included. A significant decrease was found in practice variation (SD TOL rates: 0.17 control group vs. 0.10 intervention group following decision aid implementation, p=0.011). There was no significant difference in the ERCS rate or overall CS rates. A 21% reduction in the combined maternal and perinatal adverse outcomes was seen. Nationwide implementation of the DA showed a significant reduction in practice variation without an increase in the rate of cesarean section or complications, suggesting an improvement in equality of care

    Graphical Tasks to Measure Upper Limb Function in Patients With Parkinson's Disease:Validity and Response to Dopaminergic Medication

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    The most widely used method to assess motor functioning in Parkinson's disease (PD) patients is the unified Parkinson's disease rating scale-III (UPDRS-III). The UPDRS-III has limited ability to detect subtle changes in motor symptoms. Alternatively, graphical tasks can be used to provide objective measures of upper limb motor dysfunction. This study investigated the validity of such graphical tasks to assess upper limb function in PD patients and their ability to detect subtle changes in performance. Fourteen PD patients performed graphical tasks before and after taking dopaminergic medication. Graphical tasks included figure tracing, writing, and a modified Fitts' task. The Purdue pegboard test was performed to validate these graphical tasks. Movement time (MT), writing size, and the presence of tremor were assessed. MT on the graphical tasks correlated significantly with performance on the Purdue pegboard test (Spearman's rho > 0.65; p <0.05). MT decreased significantly after the intake of dopaminergic medication. Tremor power decreased after taking dopaminergic medication in most PD patients who suffered from tremor. Writing size did not correlate with performance on the Purdue pegboard test, nor did it change after taking medication. Our set of graphical tasks is valid to assess upper limb function in PD patients. MT proved to be the most useful measure for this purpose. The response on dopaminergic medication was optimally reflected by an improved MT on the graphical tasks in combination with a decreased tremor power, whereas writing size did not respond to dopaminergic treatment
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