Population niche width is driven by within-individual niche expansion and individual specialization in introduced brook trout in mountain lakes.

The width of a population's resource-use niche is determined by individual diet breadth ("within-individual component") and the degree of niche partitioning between individuals ("between-individual component"). The balance between these two factors affects ecological stability and evolutionary trajectories, and may shift as ecological opportunity permits broader population niches. Lakes in California's Sierra Nevada Mountains vary in resource diversity for introduced brook trout (Salvelinus fontinalis) due to elevation, lake morphometry, and watershed features. We compared the relative contributions of within- and between-individual niche components to two measures of the dietary niches of thirteen populations of brook trout: prey taxonomic composition and prey size distribution. For both taxonomic and size diversity of fish diets, population niche width was positively related to both the within- and between-individual components. For taxonomic diversity, the two components increased in parallel, while for size diversity, the between-individual component became more important relative to the within-individual component in populations with the greatest niche widths. Our results support the Niche Variation Hypothesis that populations with broader niches are more heterogeneous among individuals and show that individual niche width and individual specialization can operate in parallel to expand the population niche.

Combinatorial metabolism drives the naive to primed pluripotent chromatin landscape.

Since epigenetic modifications are a key driver for cellular differentiation, the regulation of these modifications is tightly controlled. Interestingly, recent studies have revealed metabolic regulation for epigenetic modifications in pluripotent cells. As metabolic differences are prominent between naive (pre-implantation) and primed (post-implantation) pluripotent cells, the epigenetic changes regulated by metabolites has become an interesting topic of analysis. In this review we discuss how combinatorial metabolic activities drive the developmental progression through early pluripotent stages.

Investigating the electronic structure of confined multiexcitons with nonlinear spectroscopies.

Strong confinement in semiconductor quantum dots enables them to host multiple electron-hole pairs or excitons. The excitons in these materials are forced to interact, resulting in quantum-confined multiexcitons (MXs). The MXs are integral to the physics of the electronic properties of these materials and impact their key properties for applications such as gain and light emission. Despite their importance, the electronic structure of MX has yet to be fully characterized. MXs have a complex electronic structure arising from quantum many-body effects, which is challenging for both experiments and theory. Here, we report on the investigation of the electronic structure of MX in colloidal CdSe QDs using time-resolved photoluminescence, state-resolved pump-probe, and two-dimensional spectroscopies. The use of varying excitation energy and intensities enables the observation of many signals from biexcitons and triexcitons. The experiments enable the study of MX structures and dynamics on time scales spanning 6 orders of magnitude and directly reveal dynamics in the biexciton manifold. These results outline the limits of the simple concept of binding energy. The methods of investigations should be applicable to reveal complex many-body physics in other nanomaterials and low-dimensional materials of interest.

Widespread correction of central nervous system disease after intracranial gene therapy in a feline model of Sandhoff disease.

Sandhoff disease (SD) is caused by deficiency of N-acetyl-ß-hexosaminidase (Hex) resulting in pathological accumulation of GM2 ganglioside in lysosomes of the central nervous system (CNS) and progressive neurodegeneration. Currently, there is no treatment for SD, which often results in death by the age of five years. Adeno-associated virus (AAV) gene therapy achieved global CNS Hex restoration and widespread normalization of storage in the SD mouse model. Using a similar treatment approach, we sought to translate the outcome in mice to the feline SD model as an important step toward human clinical trials. Sixteen weeks after four intracranial injections of AAVrh8 vectors, Hex activity was restored to above normal levels throughout the entire CNS and in cerebrospinal fluid, despite a humoral immune response to the vector. In accordance with significant normalization of a secondary lysosomal biomarker, ganglioside storage was substantially improved, but not completely cleared. At the study endpoint, 5-month-old AAV-treated SD cats had preserved neurological function and gait compared with untreated animals (humane endpoint, 4.4±0.6 months) demonstrating clinical benefit from AAV treatment. Translation of widespread biochemical disease correction from the mouse to the feline SD model provides optimism for treatment of the larger human CNS with minimal modification of approach.

Can you ever collect too many oocytes?

STUDY QUESTION: Does the chance of pregnancy keep improving with increasing number of oocytes, or can you collect too many? SUMMARY ANSWER: Clinical pregnancy (CP) and live birth (LB) rates per embryo transfer varied from 10.2 and 9.2% following one oocyte collected to 37.7 and 31.3% when >16 oocytes were collected. Regression modelling indicated success rates increased or at least stayed the same with number of oocytes collected. WHAT IS KNOWN ALREADY: It has been suggested that if >15 oocytes are collected, the success rate for fresh embryo transfers decreases. As this is counterintuitive, as more oocytes should result in more embryos, with a better choice of quality embryos, we decided to analyse the recent experience in a busy IVF unit. STUDY DESIGN, SIZE DURATION: A retrospective analysis of clinical pregnancy and live birth outcome, with respect to number of oocytes collected at Monash IVF for the 2-year period between August 2010 and July 2012, where patients under the age of 45 years underwent a fresh embryo transfer. This included 7697 stimulated cycles for IVF and ICSI. PARTICIPANT/MATERIALS, SETTING, METHODS: Statistical analysis involved data tables and graphs comparing oocyte number with outcome. Results of women who had their first oocyte collection with an embryo transfer within the reference period were analysed by logistic regression analysis including other covariates that might influence pregnancy outcome. Analysis was also carried out of all the 7679 oocyte collections undertaken, resulting in fresh embryo transfers by generalized estimating equations to allow for the within subject correlation in outcomes for repeated treatments. MAIN RESULTS AND THE ROLE OF CHANCE: The number of oocytes collected varied from 1 to 48. Clinical pregnancy and live birth rates per embryo transfer varied from 10.2 and 9.2% when only one oocyte was collected to 37.7 and 31.3% when >16 oocytes were collected. Regression modelling indicated success rates increased or at least stayed the same or with the number of oocytes collected. The percentage of women with embryos cryopreserved increased from under 20% with <4 oocytes collected to over 70% with >16 oocytes collected. There was a slight increase (from 18 to 22%) in oocyte immaturity and a more marked increase (from 0 to 3%) in cancelling fresh transfers to prevent Ovarian Hyperstimulation Syndrome (OHSS) with increase in number of oocytes collected above 16. The results of this study suggest that you cannot collect too many oocytes as both clinical pregnancy and live birth rates do not decrease with high numbers of oocytes collected. However, once >15 oocytes are collected, everything gets quite uncertain. LIMITATIONS, REASONS FOR CAUTION: As the data become sparse above 15 oocytes, we could not demonstrate a significant increase in pregnancy rates above this number. Larger studies would be required to answer the question whether there is a plateau, or rates continue to increase. The negative of aggressive stimulation to produce many oocytes is that the risk of OHSS increases, and this is the most serious complication of ovarian stimulation. STUDY FUNDING/COMPLETING OF INTERESTS: No funding was required. There is no conflict of interest, except that G.K., V.M. and C.M. are shareholders in Monash IVF Pty Ltd.

Imaging of frequent emergency department users with alcohol use disorders.

BACKGROUND: Patients with altered level of consciousness secondary to alcohol use disorders (AUDs) often undergo imaging in the emergency department (ED), although the frequency and yield of this practice over time are unknown. STUDY OBJECTIVES: We describe the use of imaging, the associated ionizing radiation exposure, cumulative costs, and identified acute and chronic injuries and abnormalities among frequent users of the ED with AUDs. METHODS: This is a retrospective case series of individuals identified through an administrative database having 10 or more annual ED visits in 2 consecutive years who were prospectively followed for a third year. International Classification of Diseases, 9(th) Revision, Clinical Modification and Current Procedural Terminology codes were used to select individuals with alcohol-related diagnoses, track imaging procedures, and calculate cost. Diagnoses, imaging results, and radiation exposure per computed tomography (CT) study were abstracted from the medical record. RESULTS: Fifty-one individuals met inclusion criteria and had a total of 1648 imaging studies over the 3-year period. Subjects had a median of 5 (interquartile range [IQR] 2-10) CT scans, 20 (IQR 10-33) radiographs, 28.3 mSv (IQR 8.97-61.71) ionizing radiation, 0.2% (IQR 0.07-0.4) attributable risk of cancer, and $2979 (IQR 1560-5440) in charges using a national rate. The incidence of acute fracture or intracranial head injury was 55%, and 39% of the cohort had a history of moderate or severe traumatic brain injury. CONCLUSION: The remarkable use of imaging and occurrence of injury among these highly vulnerable and frequently encountered individuals compels further study to refine clinical practices through the development of evidence-based, effective interventions.

The homeobox gene mirror links EGF signalling to embryonic dorso-ventral axis formation through notch activation.

Recent studies in vertebrates and Drosophila melanogaster have revealed that Fringe-mediated activation of the Notch pathway has a role in patterning cell layers during organogenesis. In these processes, a homeobox-containing transcription factor is responsible for spatially regulating fringe (fng) expression and thus directing activation of the Notch pathway along the fng expression border. Here we show that this may be a general mechanism for patterning epithelial cell layers. At three stages in Drosophila oogenesis, mirror (mirr) and fng have complementary expression patterns in the follicle-cell epithelial layer, and at all three stages loss of mirr enlarges, and ectopic expression of mirr restricts, fng expression, with consequences for follicle-cell patterning. These morphological changes are similar to those caused by Notch mutations. Ectopic expression of mirr in the posterior follicle cells induces a stripe of rhomboid (rho) expression and represses pipe (pip), a gene with a role in the establishment of the dorsal-ventral axis, at a distance. Ectopic Notch activation has a similar long-range effect on pip. Our results suggest that Mirror and Notch induce secretion of diffusible morphogens and we have identified TGF-beta (encoded by dpp) as such a molecule in germarium. We also found that mirr expression in dorsal follicle cells is induced by the EGF-receptor (EGFR) pathway and that mirr then represses pip expression in all but the ventral follicle cells, connecting EGFR activation in the dorsal follicle cells to repression of pip in the dorsal and lateral follicle cells. Our results suggest that the differentiation of ventral follicle cells is not a direct consequence of germline signalling, but depends on long-range signals from dorsal follicle cells, and provide a link between early and late events in Drosophila embryonic dorsal-ventral axis formation.

18†Engaging with young people to improve research, services and workforce development: eye-YPAG and 'visually' workshops.

Involving children and young people (CYP) in service and research design improves quality and accessibility. Running events in schools to invite CYP to volunteer and explore careers in the NHS may contribute to uptake of training posts and developing the NHS workforce.Here we evaluate two activities with CYP, our Young Person's Advisory Group for research (eye-YPAG) and our workshop for secondary schools, 'visually'.We evaluated eye-YPAG in focus groups and online surveys with group members, parents/carers, researchers, facilitators and funders. We conducted thematic analysis and descriptive statistics. To evaluate 'visually', we monitored the numbers of workshops and young people applying for volunteering roles. We asked those who started working with us about their experience.eye-YPAG members valued social and creative aspects as well as learning about research and developing skills and confidence. Researchers reported that CYP gave novel suggestions, modifying research plans, and that their different perspective was helpful in making research more relevant for children and families.Over 6 months, we held 15 'visually' workshops in secondary schools. Ninety students applied for volunteering roles, and 20 have completed the Human Resources onboarding process. Young volunteers report that this work has increased their confidence and that they have gained insights into how a hospital works. One is considering training to become an orthoptist.Both eye-YPAG and 'visually' are available to all eye researchers and units in the UK and can facilitate outreach activities.

Mediating effects of inequitable gender norms on intimate partner violence and contraceptive use in a cluster randomized control trial in Niger: A causal inference mediation analysis.

Background: Gender inequity, a deeply-rooted driver of poor health globally, is expressed in society through gender norms, the unspoken rules that govern gender-related roles and behavior. The development of public health interventions focused on promoting equitable gender norms are gaining momentum internationally, but there remain critical gaps in the evidence about how these interventions are working to change behavioral outcomes. Methods: A four-arm cluster randomized control trial (cRCT) was conducted to evaluate the effects of the Reaching Married Adolescents in Niger (RMA) intervention on modern contraceptive use and intimate partner violence (IPV) among married adolescent girls and their husbands in Dosso, Niger (T1: 1042 dyads; 24 mos. follow-up: 737 dyads, 2016-2019). This study seeks to understand if changes in perceived inequitable gender norms among husbands are the mechanism behind effects on modern contraceptive use and IPV. We estimated natural direct and indirect effects via these gender norms using inverse odds ratio weighting. An intention-to-treat approach and a difference-in-differences estimator in a hierarchical linear probability model was used to estimate prevalence differences, along with bootstrapping to estimate confidence intervals. Results: The total effects of the RMA small group intervention (Arm 2) is estimated to be an 8% reduction in prevalence of IPV [95% CI: -0.18, 0.01]. For this arm, the natural indirect effect through gender inequitable social norms is associated with a 2% decrease (95% CI: -0.07, 0.12), accounting for 22.3% of this total effect, and the natural direct effect with a 6% decrease (95% CI: -0.20, -0.02) in IPV. Of the total effect of the RMA household visit intervention (Arm 1) on contraceptive use (20% increase), indirect effects via inequitable gender norms were associated with an 11% decrease (95% CI: -0.18, -0.01) and direct effects with a 32% increase (95% CI: 0.13, 0.44) in contraceptive use. For the combination arm, of the total effects on contraceptive use (19% increase), indirect effects were associated with a 9% decrease (95% CI: -0.20, 0.02) and direct effects with a 28% increase (95% CI: 0.12, 0.46). Conclusion: The present study contributes experimental evidence that the small group RMA intervention reduced IPV partially via reductions in perceived inequitable gender norms among husbands. Evidence also suggests that increases in perceived inequitable gender norms resulted in decreased contraceptive use among those receiving the household visit intervention component. Not only do these results open the "black box" around how the RMA small group intervention may create behavior change to help inform its future use, they provide evidence supporting behavior change theories and frameworks that postulate the importance of changing underlying social norms in order to reduce IPV and increase modern contraceptive use.

Generation and characterization of phage-GnRH chemical conjugates for potential use in cat and dog immunocontraception.

Overpopulation of cats and dogs is a serious worldwide problem that demands novel, safe and cost-effective solutions. The objective of this study was to generate and characterize phage-peptide conjugates with gonadotropin-releasing hormone (GnRH) for potential use as an immunocontraceptive. A filamentous phage vector f5-8 with wild-type phage coat proteins was used as a carrier for construction of chemical conjugates with GnRH, a peptide that acts as a master reproductive hormone. In such conjugates, the phage body plays the role of a carrier protein, while multiple copies of GnRH peptide stimulate production of neutralizing anti-GnRH antibodies potentially leading to contraceptive effects. To generate the constructs, four different GnRH-based peptides were synthesized and conjugated to phage particles in a two-step procedure: (i) peptides were reacted with phage to form a conjugate using 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride chemistry (EDC) and (ii) the conjugates were separated from remaining free peptides by dialysis. Formation and specificity of phage-GnRH conjugates were confirmed by three independent methods: spectrophotometry, electron microscopy and ELISA. When the conjugates were tested for interaction with sera collected from cats and dogs immunized with GnRH-based vaccines in independent studies, strong specific ELISA signals were obtained, suggesting the potential use of the conjugates for cat and dog immunosterilization. The ability of the conjugates to stimulate production of anti-GnRH antibodies in vivo was evaluated in mice. While optimization of dose, immunization route and adjuvant still requires investigation, our preliminary results demonstrated the presence of anti-GnRH antibodies in sera of mice immunized with such conjugates. Fertility trials in cats and dogs will be needed to evaluate contraceptive potentials of the phage-GnRH peptide chemical conjugates.

Quinn's advantage fertilization medium enhances zona pellucida-induced acrosome reaction compared with human tubal fluid medium.

The aim of this study was to compare sperm velocity, hyperactivation, zona pellucida (ZP) binding and ZP-induced acrosome reaction (AR) between Quinn's advantage fertilization (QAF), human tubal fluid (HTF) and Ham's F10 media. Semen samples were obtained from normozoospermic men and motile spermatozoa were prepared by gradient centrifugation (PureSperm). Unfertilized oocytes from clinical IVF were used for spermatozoa-oocyte interaction tests. Sperm velocity and hyperactivation were assessed using a Hamilton-Thorn motility analyser. When media were supplemented with human albumin, sperm motility and velocity and sperm binding were not significantly different between QAF and HTF. However, ZP-induced AR was significantly higher with QAF than HTF (42±22 versus 21±18, P<0.th001). Sperm velocity, hyperactivation and sperm binding were also significantly higher in QAF than Ham's F10 media. Supplementation of media with either human serum or human albumin showed no difference in effect on all sperm test results. In conclusion, QAF medium significantly enhances ZP-induced AR which is essential for sperm penetration. Thus QAF appears to be a better medium than HTF for sperm fertilizing ability in conventional IVF.

Functional integration of striatal allografts in a primate model of Huntington's disease.

Huntington's disease is an autosomal dominant, inherited disorder that results in progressive degeneration of the basal ganglia (especially the neostriatal caudate nucleus and putamen) and other forebrain structures and is associated with a clinical profile of movement, cognitive and psychiatric impairments for which there is at present no effective therapy. Neuropathological, neurochemical and behavioral features of the disease can all be reproduced in experimental animals by local injection of excitotoxic or metabolic toxins into the neostriatum. All these features of the disease can be alleviated, at least in rats, by transplantation of embryonic striatal tissue into the degenerated striatum, which was the basis for commencing the first clinical trials of striatal transplantation in Huntington's patients. However, although rat striatal xenografts may temporarily reduce apomorphine-induced dyskinesias in monkeys, there has been no demonstration that allograft techniques that work well in rats translate effectively to the much larger differentiated striatum of primates. Here we demonstrate good survival, differentiation and integration of striatal allografts in the primate neostriatum, and recovery in a test of skilled motor performance. Long-term graft survival in primates indicates probable success for clinical transplants in Huntington's disease; in addition, our data suggest that graft placement has a direct influence on the pattern and extent of functional recovery.

Stem cell division is regulated by the microRNA pathway.

One of the key characteristics of stem cells is their capacity to divide for long periods of time in an environment where most of the cells are quiescent. Therefore, a critical question in stem cell biology is how stem cells escape cell division stop signals. Here, we report the necessity of the microRNA (miRNA) pathway for proper control of germline stem cell (GSC) division in Drosophila melanogaster. Analysis of GSCs mutant for dicer-1 (dcr-1), the double-stranded RNaseIII essential for miRNA biogenesis, revealed a marked reduction in the rate of germline cyst production. These dcr-1 mutant GSCs exhibit normal identity but are defective in cell cycle control. On the basis of cell cycle markers and genetic interactions, we conclude that dcr-1 mutant GSCs are delayed in the G1 to S transition, which is dependent on the cyclin-dependent kinase inhibitor Dacapo, suggesting that miRNAs are required for stem cells to bypass the normal G1/S checkpoint. Hence, the miRNA pathway might be part of a mechanism that makes stem cells insensitive to environmental signals that normally stop the cell cycle at the G1/S transition.

New assisted reproductive technology laws in Victoria: a genuine overhaul or just cut and paste?

A new Assisted Reproductive Treatment Act was passed in Victoria on December 2008 and came into effect on 1 January 2010. The new legislation changed who was eligible for assisted reproductive technology (ART) and the types of services that clinics could provide. This article reports on interviews with service providers in Victoria who experience first hand the impact of legislation on clinical practice and patients, as well as regulators who are able to provide insight into the values underpinning the regulatory framework. The new legislation was viewed by all participants as an improvement on the old Act because of the removal of discriminatory and ambiguous aspects. The authors argue that while some of the details of the legislation have changed, the underlying principles and the framework have not.

Comparison of visual and computerised antenatal cardiotocography in the prevention of perinatal morbidity and mortality. A systematic review and meta-analysis.

INTRODUCTION: Antenatal cardiotocography (CTG) is used to monitor fetal well-being. There are two methods: visual (vCTG) or computerised (cCTG). An earlier Cochrane review compared the effects of both approaches on maternal and fetal outcomes. The objective of this systematic review was to update this search and identify studies not included in the Cochrane review. MATERIALS AND METHODS: MEDLINE, EMBASE, CINAHL and MIDIRS databases were searched up to February 2021. We included randomised controlled trials (RCT) and non-randomised studies (NRS) of pregnant women receiving antenatal CTG with comparison of cCTG to vCTG and clinical outcomes. The Cochrane Risk of Bias Tool and Joanna Briggs Institute Critical Appraisal Checklist were used for quality assessment. Data is presented as risk ratios with 95% confidence intervals and I2 is used as the statistical measure of heterogeneity. RESULTS: Three RCTs and three NRS were included. Meta-analysis of RCTs demonstrated a non-significant reduction in all-cause perinatal mortality (RR 0.23 [95%CI 0.04-1.30]), preventable perinatal mortality excluding congenital anomalies (RR 0.27 [95% CI 0.05-1.56]) and cesarean section (RR 0.91 [95%CI 0.68-1.22]). All RCTs included high-risk women and had a high risk of bias. There was one antenatal stillbirth across the three RCTs (n = 497). The NRS were at high-risk of bias and statistical analysis was not possible due to heterogeneity. Individual findings suggest reduced investigation and better prediction of neonatal outcomes with cCTG. CONCLUSIONS: There is a non-significant reduction in perinatal mortality with cCTG. Despite no clear reduction in perinatal mortality and morbidity with cCTG, it is objective and may reduce time spent in hospital and further investigations for women.

Men's experiences of infertility and infertility treatment 5 years after diagnosis of male factor infertility: a retrospective cohort study.

BACKGROUND: The aim of this study was to describe the perceptions of infertile men regarding the impact of infertility on their intimate relationships, their experience of treatment and their sources of information and support. METHODS: A cross-sectional survey of a consecutive cohort of men diagnosed 5 years earlier as infertile at Melbourne IVF and the Royal Women's Hospital Reproductive Services, Melbourne was conducted. Study-specific questions assessed the impact of male factor infertility on the intimate relationships, their perceived quality of infertility-related health care and their preferred sources of infertility-related information and personal support and the effectiveness of these. RESULTS: The response rate was 41% (112/276). Male factor infertility was reported to have had a negative impact on the intimate partner relationship by 25% of men, and 32% reported a negative effect on their sexual satisfaction. Satisfaction with medical care and clinic information was high and not influenced by the outcome of the treatment. Clinic-provided information and discussion with clinic staff were the most strongly preferred sources of information, and the partner and clinic staff were the most valued sources of personal support. Very few men found support groups useful and less than half confided in friends. CONCLUSIONS: The findings suggest that for a significant subgroup of men, male factor infertility affects their intimate relationship negatively. Wider sources of social support are not used by infertile men as they rely predominantly on clinic-provided information and support. This indicates that psychologically informed supportive clinical care is particularly important for men diagnosed as infertile.

Prevalence and risk factors for obstetric haemorrhage in 6730 singleton births after assisted reproductive technology in Victoria Australia.

BACKGROUND: Obstetric haemorrhages have been reported to be increased after assisted reproduction technologies (ART) but the mechanisms involved are unclear. METHODS: This retrospective cohort study compared the prevalence of antepartum haemorrhage (APH), placenta praevia (PP), placental abruption (PA) and primary post-partum haemorrhage (PPH) in women with singleton births between 1991 and 2004 in Victoria Australia: 6730 after IVF/ICSI, 24 619 from the general population, 779 after gamete intrafallopian transfer (GIFT) and 2167 non-ART conceptions in infertile patients. Risk factors for haemorrhages in the IVF/ICSI group were examined by logistic regression. RESULTS: The IVF/ICSI group had more APH: 6.7 versus 3.6% (adjusted OR 2.0; 95% CI 1.8-2.3), PP: 2.6 versus 1.1% (2.3; 1.9-2.9), PA: 0.9 versus 0.4% (2.1; 1.4-3.0) and PPH: 11.1 versus 7.9% (1.3; 1.2-1.4) than the general population. APH, PP and PA were as frequent in the GIFT group as in the IVF/ICSI group, but were less frequent in the non-ART group. Within the IVF/ICSI group, fresh compared with frozen thawed embryo transfers (FET) was associated with more frequent APH (1.5; 1.2-1.8) and PA (2.1; 1.2-3.7) and the odds ratio increased with number of oocytes collected (1.02; 1.00-1.04). Endometriosis patients had more PP (1.7; 1.2-2.4) and PPH (1.3; 1.1-1.6) than those without endometriosis. FET in artificial cycles was associated with increased PPH (1.8; 1.3-2.6) compared with FET in natural cycles. CONCLUSIONS: Obstetric haemorrhages are more frequent with singleton births after IVF, ICSI and GIFT. The exploratory analysis of factors in the IVF/ICSI group, showing associations with fresh embryo transfers in stimulated cycles, endometriosis and hormone treatments, suggests that events around the time of implantation may be responsible and that suboptimal endometrial function is the critical mechanism.

Increased risk of blastogenesis birth defects, arising in the first 4 weeks of pregnancy, after assisted reproductive technologies.

BACKGROUND: The reasons for increased birth defect prevalence following in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) are largely unknown. Classification of birth defects by pathology rather than organ system, and examination of the role of embryo freezing and thawing may provide clues to the mechanisms involved. This study aimed to investigate these two factors. METHOD: Data on 6946 IVF or ICSI singleton pregnancies were linked to perinatal outcomes obtained from population-based data sets on births and birth defects occurring between 1991 and 2004 in Victoria, Australia. These were compared with 20,838 outcomes for singleton births in the same population, conceived without IVF or ICSI. Birth defects were classified according to pathogenesis. RESULTS: Overall, birth defects were increased after IVF or ICSI [adjusted odds ratio (OR) 1.36; 95% CI: 1.19-1.55] relative to controls. There was no strong evidence of risk differences between IVF and ICSI or between fresh and thawed embryo transfer. However, a specific group, blastogenesis birth defects, were markedly increased [adjusted OR 2.80, 95% CI: 1.63-4.81], with the increase relative to the controls being significant for fresh embryo transfer (adjusted OR 3.65; 95% CI: 2.02-6.59) but not for thawed embryo transfer (adjusted OR 1.60; 95% CI: 0.69-3.69). CONCLUSION: Our findings suggest that there is a specific risk of blastogenesis birth defects arising very early in pregnancy after IVF or ICSI and that this risk may be lower with use of frozen-thawed embryo transfer.

The conserved WW-domain binding sites in Dystroglycan C-terminus are essential but partially redundant for Dystroglycan function.

BACKGROUND: Dystroglycan (Dg) is a transmembrane protein that is a part of the Dystrophin Glycoprotein Complex (DGC) which connects the extracellular matrix to the actin cytoskeleton. The C-terminal end of Dg contains a number of putative SH3, SH2 and WW domain binding sites. The most C-terminal PPXY motif has been established as a binding site for Dystrophin (Dys) WW-domain. However, our previous studies indicate that both Dystroglycan PPXY motives, WWbsI and WWbsII can bind Dystrophin protein in vitro. RESULTS: We now find that both WW binding sites are important for maintaining full Dg function in the establishment of oocyte polarity in Drosophila. If either WW binding site is mutated, the Dg protein can still be active. However, simultaneous mutations in both WW binding sites abolish the Dg activities in both overexpression and loss-of-function oocyte polarity assays in vivo. Additionally, sequence comparisons of WW binding sites in 12 species of Drosophila, as well as in humans, reveal a high level of conservation. This preservation throughout evolution supports the idea that both WW binding sites are functionally required. CONCLUSION: Based on the obtained results we propose that the presence of the two WW binding sites in Dystroglycan secures the essential interaction between Dg and Dys and might further provide additional regulation for the cytoskeletal interactions of this complex.

Enhancement of sperm-zona pellucida (ZP) binding capacity by activation of protein kinase A and C pathways in certain infertile men with defective sperm-ZP binding.

BACKGROUND: Defective sperm-zona pellucida (ZP) binding (DSZPB) is a common cause of failure of fertilization in vitro. This study was to determine if DSZPB is caused by defective pathways upstream of protein kinase A (PKA) and C (PKC), or reduced protein tyrosine phosphorylation (TP). METHODS: Infertile men with DSZPB and either normal sperm morphology (NSM) > or = 14% (n = 15) or < or =5% (n = 15) were studied. Sperm-ZP binding test was performed by incubation of motile sperm with oocytes for 2 h with or without dibutyryl cyclic AMP (dbcAMP, PKA activator) or phorbol myristate acetate (PMA, PKC activator). TP of capacitated sperm in medium was assessed by immunofluorescence with an anti-phosphotyrosine monoclonal antibody. RESULTS: For normal sperm with normal sperm-ZP binding, both PMA and dbcAMP significantly enhanced sperm-ZP binding in a dose-response manner. Only dbcAMP, but not PMA, significantly increased TP of capacitated sperm. In DSZPB men with severe teratozoospermia (NSM < or = 5%), neither PMA nor dbcAMP enhanced sperm-ZP binding, despite dbcAMP significantly increasing the TP of capacitated sperm for all samples. In contrast, for DSZPB with NSM > or = 14%, PMA caused significantly increased sperm binding up to normal levels (> or =40 sperm bound/ZP) in five men, and dbcAMP had a similar result in two men. Again TP was significantly enhanced only by dbcAMP, but not by PMA. CONCLUSIONS: There is defective signalling in pathways upstream of PKC and PKA in some men with DSZPB and normal semen analysis. Stimulation of TP by dbcAMP does not enhance sperm-ZP binding capacity in DSZPB men with low TP, regardless of sperm morphology.