Adaptation and content validation of measure yourself medical outcomes profile (MYMOP) for 7-11 year-old children.

BACKGROUND: The Measure Yourself Medical Outcome Profile (MYMOP) is an individualised tool designed for adults but used with children without any evidence of validation in this population. Individualised instruments are patient-specific rather than disease-specific and therefore can be applied across various health conditions. This study sought to adapt, and content validate the MYMOP for application in 7-11 year old children. METHODS: There were two main phases of the four iterations: expert consultation (three rounds) and interviews with child-parent pairs at the Outpatient clinics of a Children's Hospital. Thematic analysis was undertaken using an inductive, interpretative approach. RESULTS: Four paediatricians completed the first survey, five paediatricians participated in the focus group, and four paediatric health-related quality of life (HRQOL) research experts completed the second survey. Several changes were recommended to the MYMOP by the expert groups. Twenty-five children (17 general medicine, and 8 diabetes/endocrine clinic) aged 7-11 years completed the draft paediatric MYMOP (P-MYMOP) and were interviewed. Results demonstrated that the majority of participants were able to identify their own problems and activity limitations, and all participants understood the 7-point faces scale. Most parents and children perceived that the P-MYMOP would be useful to complete before clinic appointments. CONCLUSIONS: The P-MYMOP is the first content-validated generic individualised HRQOL measure for children 7-11 years old. Given that validation is an iterative process, further research to assess its feasibility, reliability, and construct validity is required.

Asymmetric expression of proteins in the granules of the placentomal Binucleate cells in Giraffa camelopardalis†.

Mature granulated trophoblast binucleate cells (BNC) have been found in all ruminant placentas examined histologically so far. BNC are normally fairly evenly distributed throughout the fetal villus and all their granules contain a similar variety of hormones and pregnancy associated glycoproteins (PAGs). Only the Giraffe is reported to show a different BNC protein expression, this paper is designed to investigate that. Gold labelled Lectin histochemistry and protein immunocytochemistry were used on deplasticised 1 µm sections of a wide variety of ruminant placentomes with a wide range of antibodies and lectins. In the Giraffe placentomes, even though the lectin histochemistry shows an even distribution of BNC throughout the trophoblast of the placental villi, the protein expression in the BNC granules is limited to the BNC either in the apex or the base of the villi. Placental lactogens and Prolactin (PRL) are present only in basally situated BNC: PAGs only in the apical BNC. PRL is only found in the Giraffe BNC which react with many fewer of the wide range of antibodies used here to investigate the uniformity of protein expression in ruminant BNC. The possible relevance of these differences to ruminant function and evolution is considered to provide a further example of the versatility of the BNC system.

Modeling human peri-implantation placental development and function†.

It is very difficult to gain a better understanding of the events in human pregnancy that occur during and just after implantation because such pregnancies are not yet clinically detectable. Animal models of human placentation are inadequate. In vitro models that utilize immortalized cell lines and cells derived from trophoblast cancers have multiple limitations. Primary cell and tissue cultures often have limited lifespans and cannot be obtained from the peri-implantation period. We present here two contemporary models of human peri-implantation placental development: extended blastocyst culture and stem-cell derived trophoblast culture. We discuss current research efforts that employ these models and how such models might be used in the future to study the "black box" stage of human pregnancy.

Effects of racism on the socio-emotional wellbeing of Aboriginal Australian children.

BACKGROUND: Racism is a pervasive experience in the life of Aboriginal Australians that begins in childhood. As a psychosocial stressor, racism compromises wellbeing and impacts developmental trajectories. The purpose of the present study was to estimate the effect of racism on indicators of Australian Aboriginal child socio-emotional wellbeing (SEWB) at one to two years after exposure. Age-related differences in the onset of symptoms were explored. METHODS: Data from the B- and K-cohorts of the Longitudinal Study of Indigenous Children were used (aged 6 to 12 years). Racism, confounding variables, and the Strengths and Difficulties Questionnaire (a measure of SEWB) were collected by questionnaires and guided interviews with each child's main caregiver. Adjusted Poisson regression was used to estimate the relative risk (RRa) effects of racism on SEWB for both cohorts separately. RRa were pooled in a random effects meta-analysis. RESULTS: Exposure to racism was associated with an adjusted point estimate indicating a 41% increased risk for total emotional and behavioural difficulties, although the confidence intervals were wide (pooled RRa 1.41, 95% CI 0.75, 2.07). Analyses by cohort showed younger children had higher RRa for total difficulties (RRa 1.72, 95% CI 1.16, 2.54), whilst older children had higher RRa for hyperactive behaviour (RRa 1.66, 95% CI 1.01, 2.73). CONCLUSIONS: The effects observed contributes to our understanding of the impact of racism on Aboriginal Australian children. Support for emotional and behavioural difficulties, and hyperactive behaviour, for Aboriginal children might help counteract the effects of racism. Future longitudinal research and policies aimed at reducing racism in Australian society are necessary.

Service and support needs following pediatric brain injury: perspectives of children with mild traumatic brain injury and their parents.

OBJECTIVE: To provide a qualitative examination of the service and support needs of children who have had a mild traumatic brain injury (mTBI), and their parents, in order to improve clinical services. METHODS: Semi-structured interviews were conducted with 9 children (8-12 years; M = 10.6 years, SD = 0.8) and their parents (n = 9) 29-55 days (M = 34 days; SD = 9.3) after presenting to an Australian Paediatric Emergency Department (PED) for mTBI. Children's post-concussive symptoms (PCS) were additionally measured using the Post-Concussive Symptom Inventory (PCSI). Audio recordings were transcribed, and a thematic analysis was conducted. RESULTS: Post-injury needs were reflected in four main themes: Communication; Family Burden; Continuity of Care; and Social and Community Support. These themes reflected children's and parents' needs for information, emotional/social/community support, and follow-up care. Both the children's and parents' needs, and the extent to which they were met, appeared to be related to the severity and duration of the child's PCS. CONCLUSIONS: Dedicated pediatric mTBI follow-up services that build on family's resources and meet their individual needs for information, emotional support, and referral may assist in optimizing post-injury outcomes.

Spinal dural arteriovenous fistula: delay to radiological diagnosis and sources of radiological error.

AIM: To highlight the magnetic resonance imaging (MRI) signs associated with spinal dural arteriovenous fistula (SDAVF) through categorisation of sources of radiological error and investigation of the delay to radiological diagnosis. MATERIAL AND METHODS: This was a retrospective, observational study of cases referred to a neuroscience centre over 11 years. All patients who underwent spinal digital subtraction angiography (DSA) with a subsequent diagnosis of SDAVF were identified. Prior imaging was reviewed and compared with the formal reports issued. RESULTS: Thirty-seven patients with SDAVF were initially imaged in seven institutions. Radiological abnormalities including intradural vessels (37/37, 100%), cord T2 signal change (34/37, 91.9%), and cord expansion (26/37, 70.2%) were present on prior MRI. These signs were not recognised in 22/37 (59.5%), 7/34 (20.5%), and 15/26 (57.7%) of cases, respectively. Increased T2 signal in the cord was the most commonly identified sign (27/34; 79.4%), but prompted either no diagnosis (7/34; 20.5%) or differential diagnoses including ischaemic, inflammatory, or neoplastic aetiologies or a syrinx in 11/34 (32.4%). An appropriate diagnosis was made on initial MRI in 15 patients (40.5%). The time from initial imaging to diagnosis was significantly delayed for those patients who did not have an arteriovenous vascular aetiology included in the initial differential diagnosis (281 (423.3) days versus 22 (15.7) days, p=0.03). CONCLUSION: SDAVF have imaging features that are frequently missed or misinterpreted. This results in a significant delay to definitive diagnosis and therefore treatment.

Sun-related behaviours among young Australians with Asian ethnic background: differences according to sociocultural norms and skin tone perceptions.

Deliberate tanning, poor sun protection and sun exposure increase an individual's risk for skin cancer. Recent evidence suggests that individuals of Asian heritage have lower incidence of skin cancer than Caucasians but that their post-diagnosis outcomes are often worse. In Western cultures tanning behaviours are often motivated by a desire for 'attractive' tanned skin. Conversely, a light complexion is desired in a number of Asian cultures and may consequently serve to protect this group from excessive and risky sun exposure behaviours. This possibility is yet to be tested, with little known about the sun-related behaviours of Asian people residing in Australia. The present study involves 140 South Australian young adults who report having Asian heritage. Results show that the majority of female participants, and significantly fewer males, reported participating in deliberate outdoor tanning behaviour. Perceptions of family, peer and media tanning norms influenced behaviour, with peer norms being the strongest predictor. The desire for a lighter skin tone was associated with increased sun-protective behaviour and a lower number of previous severe sunburns. As a significant proportion of participants engaged in deliberate tanning behaviour, it is recommended that future research continue to explore factors associated with tanning, including an explicit measure of culture.

Predictors of mental health in adults with congenital craniofacial conditions attending the Australian craniofacial unit.

Objective : Adults with craniofacial conditions experience more psychosocial problems than adults in the general population, but little is known about the factors that render a person more or less susceptible to these problems. Guided by research on adults with other conditions that affect appearance, this study examined predictors of psychosocial outcome in adults with craniofacial conditions. Design : Single-sample cross-sectional design. Setting : The Australian Craniofacial Unit, Women's and Children's Hospital, Adelaide, one of the main craniofacial treatment centers in Australia. Participants : Adults (N  =  93; 36.9% of the potential sample) with congenital craniofacial conditions (excluding cleft lip and/or cleft palate) who were treated in the Australian Craniofacial Unit. Main Outcome Measures : All participants completed measures assessing anxiety, depression, and quality of life (Hospital Anxiety and Depression Scale, Short-Form Health Survey) and variables predicted to affect these outcomes (SF-36 Health Survey - Multidimensional Scale of Perceived Social Support, Rosenberg Self-Esteem Scale, Cleft Satisfaction Profile, Brief Fear of Negative Evaluation Scale, Derriford Appearance Scale). Results : Multiple regression analyses revealed that anxiety was predicted by social support, self-esteem, and fear of negative evaluation, while depression was predicted by self-esteem and social support. Physical quality of life was not predicted by any of the measures. Satisfaction with appearance, gender, age, and education were not related to outcome. Conclusions : Interventions designed to increase perceived social support and self-esteem and reduce fear of negative evaluation appear to be indicated and may assist in establishing a causal relationship between these variables.

The effect of visible facial difference on personal space during encounters with the general public.

Previous research has found that people with visible differences are granted more physical space than people without visible differences during encounters with the general public. This study aimed to examine whether given significant sociocultural changes, this remains the case in contemporary Australia. The personal space afforded to a person with a visible difference (with a temporary difference--a scar and a permanent difference--a strawberry hemangioma) or a person without a visible difference by 408 pedestrians on a busy pedestrian walkway in the central business district of Adelaide, Australia, was measured. This was a replication and extension of a study by N. Rumsey, R. Bull, and D. Gahagan (1982). Pedestrians stood no further away from the model in the visibly different conditions than in the nonvisibly different conditions. Pedestrians stood an average of 128 cm away in the control condition, 120 cm away in the scar condition, and 140 cm away in the birthmark condition. People did not stand to the nonvisibly different (left) side of the model more frequently in the visibly different conditions than in the nonvisibly different conditions. As the original research by N. Rumsey et al. is frequently cited as representing the current situation for people with visible differences, failing to replicate the result is significant. Changes may be due to either recent sociocultural changes promoting inclusion of disability or increasing social taboo against expressing overt prejudice.

Development of properly-polarized trophoblast stem cell-derived organoids to model early human pregnancy.

The development of human trophoblast stem cells (hTSC) and stem cell-derived trophoblast organoids has enabled investigation of placental physiology and disease and early maternal-fetal interactions during a stage of human pregnancy that previously had been severely restricted. A key shortcoming in existing trophoblast organoid methodologies is the non-physiologic position of the syncytiotrophoblast (STB) within the inner portion of the organoid, which neither recapitulates placental villous morphology in vivo nor allows for facile modeling of STB exposure to the endometrium or the contents of the intervillous space. Here we have successfully established properly-polarized human trophoblast stem cell (hTSC)-sourced organoids with STB forming on the surface of the organoid. These organoids can also be induced to give rise to the extravillous trophoblast (EVT) lineage with HLA-G + migratory cells that invade into an extracellular matrix-based hydrogel. Compared to previous hTSC organoid methods, organoids created by this method more closely mimic the architecture of the developing human placenta and provide a novel platform to study normal and abnormal human placental development and to model exposures to pharmaceuticals, pathogens and environmental insults. Motivation: Human placental organoids have been generated to mimic physiological cell-cell interactions. However, those published models derived from human trophoblast stem cells (hTSCs) or placental villi display a non-physiologic "inside-out" morphology. In vivo , the placental villi have an outer layer of syncytialized cells that are in direct contact with maternal blood, acting as a conduit for gas and nutrient exchange, and an inner layer of progenitor, single cytotrophoblast cells that fuse to create the syncytiotrophoblast layer. Existing "inside-out" models put the cytotrophoblast cells in contact with culture media and substrate, making physiologic interactions between syncytiotrophoblast and other cells/tissues and normal and pathogenic exposures coming from maternal blood difficult to model. The goal of this study was to develop an hTSC-derived 3-D human trophoblast organoid model that positions the syncytiotrophoblast layer on the outside of the multicellular organoid.

Effect of glucose concentration during in vitro culture of mouse embryos on development to blastocyst, success of embryo transfer, and litter sex ratio.

A high-glucose concentration in the reproductive tract during early development may result in aberrant embryo or fetal development, with effects that could have a greater impact on one sex than the other. Here, we determine if a high-glucose concentration impacts embryo development and pregnancy outcomes in a sex-specific manner in the mouse. Zygotes were cultured in potassium simple optimized medium, which typically contains 0.2 mM D-glucose, with and without additional glucose supplementation to a concentration of 28 mM. Zygote cleavage and blastocyst rate did not differ between treatments, but total and trophectoderm cell counts were reduced in blastocysts cultured in a high glucose. No differences between sexes nor inner cell mass cell number were observed within each treatment. Blastocysts developed in both media were transferred to recipients. The percentage of blastocysts resulting in viable pups was significantly reduced when the blastocysts were cultured in 28 mM glucose (74 ± 4%, controls vs. 55.8 ± 7.1%, 28 mM glucose), but conceptus loss affected both sexes equally as litter sex ratio did not differ between treatments (52.7% and 52.2% males for controls and high glucose, respectively). Pup body weight at birth was higher for males than females, but was not affected by earlier culture in high glucose. In conclusion, in vitro culture in medium with a glucose concentration approximating that of diabetic serum reduces total and trophectoderm cell numbers at the blastocyst stage and conceptus development to term, but these detrimental effects are not sex-specific.

Induced pluripotent stem cells from pigs and other ungulate species: an alternative to embryonic stem cells?

Robust embryonic stem cell (ESC) lines from livestock species have been difficult to derive and maintain, and unlike mouse ESC, have not contributed to our ability to understand directed differentiation in vitro. Nor have such cells yet provided a simpler means than pronuclear injection to manipulate the genomes of agriculturally important species, such as cattle, sheep and pigs. Induced pluripotent stem cells (iPSC) generated by reprogramming somatic cells, such as fibroblasts, with a set of stemness genes, most usually but not exclusively POU5F1, SOX2, KLF4 and c-MYC, offer an alternative to ESC in these regards, as they exhibit a pluripotent phenotype resembling that of ESC, yet are readily generated in the laboratory. Accordingly, such cells, in association with cloning technologies, may be useful for introducing complex genetic changes into livestock, although this potential has yet to be demonstrated. Porcine iPSC may be especially valuable because the pig is a prime biomedical model for tissue transplantation. In general, iPSC from livestock, like those from humans, are of the epiblast type and depend upon FGF2 and activin/nodal signalling systems to maintain their pluripotency and growth. Recent experiments, in which newly reprogrammed porcine and bovine cells were selected on a LIF-based medium in presence of specific protein kinase inhibitors, have allowed iPSC cells of the naïve type, resembling the more amenable blastocyst-derived mouse ESC and iPSC to be isolated. However, hurdles still remain if such cells are to achieve their biotechnological promise.

Psychosocial functioning in adults with congenital craniofacial conditions.

OBJECTIVE: To examine the psychosocial functioning of adults with congenital craniofacial conditions relative to normative data. DESIGN: Single sample cross-sectional design. SETTING: The Australian Craniofacial Unit, Women's and Children's Hospital, Adelaide, which is one of the main craniofacial treatment centers in Australia. PARTICIPANTS: Adults (N  =  93) with congenital craniofacial conditions (excluding cleft lip/palate) who were treated in the Australian Craniofacial Unit. MAIN OUTCOME MEASURES: All participants completed self-report scales assessing health-related quality of life (SF-36); life satisfaction, anxiety, and depression (HADS); self-esteem (Rosenberg); appearance-related concerns; perceived social support; and social anxiety. RESULTS: Overall, participants were very similar in psychosocial function to the general population. However, adults with craniofacial conditions were less likely to be married and have children (females), were more likely to be receiving a disability pension, and reported more appearance-related concerns and less social support from friends. They also reported more limitations in both their social activities, due to physical or emotional problems, and usual role activities, because of emotional problems, as well as poorer mental health. CONCLUSIONS: These results give cause to be very positive about the long-term outcomes of children who are undergoing treatment for craniofacial conditions, while also identifying specific areas that interventions could target.

Cognitive, behavioral and psychological functioning of children and adults with conservatively managed metopic synostosis.

Children diagnosed with metopic synostosis (MS) commonly experience poor neuropsychological outcomes, with research suggesting that children whose MS is managed conservatively (without surgery) potentially having worse outcomes than their operated peers. However, studies of children whose MS was managed conservatively are scarce. This study therefore examined the cognitive, behavioral, and psychological functioning of children/adults with conservatively managed MS (N = 38) and compares their outcomes to individually matched healthy controls (N = 38) of the same age and sex (matched-pairs design) from the general community. Age-appropriate, validated assessments measuring general cognition, verbal and visuospatial ability, attention and working memory, executive functioning, behavior, depression, anxiety, and satisfaction with appearance were utilized. Group differences were estimated using linear regression for (a) the overall sample and (b) by broad developmental stages: 2&3 yrs; ≥6-≤17. Moderate to large negative effects (g = -0.38 to -1.30) were evident before controlling for socio-economic status (SES), with the MS group performing significantly worse on 8 out of the 10 cognitive domains (general cognition, visuospatial ability, working memory, information processing, executive functioning: semantic & initial letter verbal fluency, switching, inhibition+switching). However, only initial letter verbal fluency (g = -0.99) and switching (g = -1.19) remained significant after adjusting for SES. The MS group displayed more behavioral problems, although this was not significant. Depression, anxiety, and satisfaction with appearance did not differ between the groups. Regular monitoring of cognitive functioning, particularly executive functioning, should be undertaken for those with conservatively managed MS.

An analysis of lectin-initiated cell agglutination in a series of CHO subclones which respond morphologically to growth in dibutyryl cyclic AMP.

We have investigated the molecular basis of the agglutinability of CHO subclones which respond differentially in terms of morphology and surface architecture in the presence of dB-cAMP in the medium. We have demonstrated that the agglutinability of these subclones with both wheat germ agglutinin (WGA) and concanavalin A (Con A) probably depends on the free lateral mobility of the lectin receptor sites in the plane of the membrane. The nonagglutinable surface architecture seems to depend on the presence in the membrane of a protease-labile peptide(s), which appears to be distinct from the lectin receptors, as well as on continuous protein and RNA synthesis. This dependence on continuous transcription and translation may be related to the maintenance of the protease-labile peptide(s) in such a state as to restrict mobility of the lectin receptors. The surface architecture defined as nonagglutinable also depends on the state of polymerization of the intracellular microtubules and microfilaments. It is suggested that these microskeletal elements serve to anchor the lectin receptors in such a manner as to restrict their mobility and thereby reduce the relative agglutinability of a cell line. We suggest that control of the free mobility of both the Con A and WGA receptor sites is dependent on two constraints, one applied by protease-labile ("surface") membrane components and the other by components of the intracellular microskeletal system.

Cognitive, behavioral and psychological functioning in children with metopic synostosis: a meta-analysis examining the impact of surgical status.

Neurodevelopmental delays are known to occur in children with metopic synostosis, but it is presently unclear whether the cognitive, behavioral and psychological outcomes of children with metopic synostosis differ to those of their healthy peers. This meta-analysis consolidated data from 17 studies (published prior to August 2017) that examined the cognitive, behavioral and psychological outcomes of children (n = 666; aged ≤19 yrs) with metopic synostosis. Hedges'g (gw) effect sizes compared the outcomes of samples with metopic synostosis (unoperated, operated) to healthy controls or normative data and, where available, the prevalence of problems/disorders was calculated. Children with unoperated metopic synostosis performed significantly worse than their healthy peers on measures of: general cognition (gw = -.38), motor functioning, (gw = -.81), and verbal (gw = -.82) and visuospatial (gw = -.92) abilities. Children with operated metopic synostosis performed significantly worse on measures of motor functioning (gw = -.45), visuospatial skills (gw = -.32), attention (gw = -.50), executive functioning (gw = -.36), arithmetic ability (gw = -.37), and behavior (gw = -.34). Cognitive, behavioral, and psychological problems were prevalent, but variable. Overall, the cognitive, behavioral, and psychological outcomes of children with metopic synostosis are generally worse than their healthy peers, regardless of surgical status. However, research is sparse, samples small, controls are rarely recruited, and the severity of metopic synostosis often not stated. Nevertheless, the findings suggest that children with metopic synostosis are likely to experience a variety of negative outcomes and should therefore receive ongoing monitoring and support.

Human embryonic stem cells as models for trophoblast differentiation.

Trophectoderm is specified from pluripotent blastomeres at some time prior to blastocyst formation. Proliferating cytotrophoblast derived from trophectoderm is the forerunner of the entire trophoblast component of the mature human placenta, including extravillous cytotrophoblast and syncytiotrophoblast. Recently human embryonic stem cells (hESC) have been employed to study these events in an in vitro situation. Here we review some of the work in this emerging area of trophoblast biology. We concentrate primarily on a model in which colonies of hESC are exposed to BMP4 in stem cell growth medium lacking FGF2. Under both low (4%) and high (20%) O(2) conditions, differentiation proceeds unidirectionally towards trophoblast from the outside of the colonies inwards, with the progression fastest under high O(2). Immunohistochemical observations performed on whole colonies combined with microarray analysis of mRNA can be employed to track developmental transitions as they occur over time and in two-dimensional space as the cells respond to BMP4.

Repression of Ets-2-induced transactivation of the tau interferon promoter by Oct-4.

Oct-4 is a POU family transcription factor associated with potentially totipotent cells. Genes expressed in the trophectoderm but not in embryos prior to blastocyst formation may be targets for silencing by Oct-4. Here, we have tested this hypothesis with the tau interferon genes (IFNT genes), which are expressed exclusively in the trophectoderm of bovine embryos. IFNT promoters contain an Ets-2 enhancer, located at -79 to -70, and are up-regulated about 20-fold by the overexpression of Ets-2 in human JAr choriocarcinoma cells, which are permissive for IFNT expression. This enhancement was reversed in a dose-dependent manner by coexpression of Oct-4 but not either Oct-1 or Oct-2. When cells were transfected with truncated bovine IFNT promoters designed to eliminate potential octamer sites sequentially, luciferase reporter expression from each construct was still silenced by Oct-4. Full repression required both the N-terminal and POU domains of Oct-4, but neither domain used alone was an effective silencer. Oct-4 and Ets-2 formed a complex in vitro in the absence of DNA through binding of the POU domain of Oct-4 to a site located between the "pointed" and DNA binding domains of Ets-2. The two transcription factors were also coimmunoprecipitated after being expressed together in JAr cells. Oct-4, therefore, silences IFNT promoters by quenching Ets-2 transactivation. The POU domain most probably binds to Ets-2 directly, while the N-terminal domain inhibits transcription. These findings provide further evidence that the developmental switch to the trophectoderm is accompanied by the loss of Oct-4 silencing of key genes.

Dynamics of the nucleated polymerization model of prion replication.

The disease process for transmissible spongiform encephalopathies (TSEs), in one way or another, involves the conversion of a predominantly alpha-helical normal host-coded prion protein (PrP(C)) to an abnormally folded (predominantly beta sheet) protease resistant isoform (PrP(Sc)). Several alternative mechanisms have been proposed for this auto-catalytic process. Here the dynamical behavior of one of these models, the nucleated polymerization model, is studied by Monte Carlo discrete-event simulation of the explicit conversion reactions. These simulations demonstrate the characteristic dynamical behavior of this model for prion replication. Using estimates for the reaction rates and concentrations, time courses are estimated for concentration of PrP(Sc), PrP(Sc) aggregates, and PrP(C) as well as size distributions for the aggregates. The implications of these dynamics on protein misfolding cyclic amplification (PMCA) is discussed.

Fluorescent in situ hybridization for sex chromosome determination before and after fertilization in mice.

In mice, the relative numbers of male and female pups per litter not only can vary but can probably change over the course of pregnancy in response to numerous environmental and physiological factors. As such, a technique is required to determine gender at several developmental stages. Here we describe a robust and accurate fluorescent in situ hybridization (FISH) procedure for determining chromosomal sex that can be applied with minimal modification to sperm, pre-and post-implantation conceptuses and recovered dead post-natal pups. Sperm was prepared for FISH analysis y using a modified microwave decondensation-denaturation technique. Preimplantation conceptuses (0.5dpc) were cultured to the morula stage before sexing. They were then acid-treated to remove the zona pellucida. Tissue homogenates from postimplantational conceptuses (8.5dpc) and stillborn pups were fixed to pre-etched slides. Specimens were hybridized with identical, commercially available DNA probes for the X (FITC) and Y (Cy3) chromosomes. Sperm ratios met the expected value of 0.5 when determined by using XY FISH. Preimplantation conceptuses pre-treated with pepsin yielded distinct fluorescence of X and Y chromosomes in morulae, whereas microwave decondensation resulted in loss of conceptuses from the slide. Both 4.0 and 8.5dpc conceptuses displayed mean sex ratios of 0.5. Post-natal FISH analysis allowed gender identification of pups that could not be sexed due to developmental abnormalities or partial cannibalism. FISH analysis of sperm and of multiple conceptuses or post-natal tissue provided a cost-effective, accurate alternative to PCR-based sex determination.