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Objective: In the West Midlands regional genetics service, cases of perinatal death with a possible genetic diagnosis are evaluated by the perinatal pathology genetic multidisciplinary team (MDT). The MDT assesses autopsy findings and suggests appropriate genomic assessment. The objective of this retrospective service evaluation was to determine the clinical utility of the MDT in assessing perinatal deaths associated with structural anomaly. This is the first evaluation since the introduction of whole-genome and whole-exome sequencing in routine clinical care., Methods: This was a retrospective service evaluation including all cases of perinatal death with an associated structural anomaly and suspected genetic etiology that underwent perinatal MDT assessment between January and December 2021. All cases received a full or partial postmortem examination and at least a chromosomal microarray analysis. Demographic characteristics, phenotype, genotype, MDT recommendations, diagnoses, outcomes and impact of postmortem analysis and genetic testing data were collected from patient case notes., Results: Overall, 123 cases were discussed at the MDT meetings in 2021. Genetic evaluation was recommended in 84 cases and accepted in 64 cases. A range of genetic tests were requested according to indication and availability. Thirty diagnoses were made in 29 cases from 26 unrelated families. The diagnostic yield was 24% (29/123) in all cases or 45% (29/64) in cases with a suspected genetic diagnosis who underwent genetic testing. Postmortem examination provided clinically actionable phenotypic data in 79% of cases. A genetic diagnosis enabled accurate recurrence risk counseling and provision of appropriate follow-up, including prenatal testing and preimplantation diagnosis for patients with inherited conditions., Conclusions: Genomic testing was a clinically useful addition to (but not a substitute for) postmortem examination in cases of perinatal death associated with structural anomaly. The MDT approach helped assess cases and plan appropriate follow-up. Expedited whole-genome sequencing or panel-agnostic analysis were most appropriate for heterogeneous presentations. This broad approach can also expand knowledge of prenatal phenotypes and detect novel disease genes, and should be a priority in future research. © 2024 International Society of Ultrasound in Obstetrics and Gynecology., (© 2024 International Society of Ultrasound in Obstetrics and Gynecology.)

Objectives: The value of prenatal exome sequencing (pES) for fetuses with structural anomalies is widely reported. In England, testing is conducted through trio exome sequencing and analysis of a gene panel. Over a 30-month period testing of 921 pregnancies resulted in a genetic diagnosis in 32.8% of cases (302/921). Here we review cases diagnosed with an inborn error of metabolism., Methods: Diagnoses of inborn errors of metabolism (IEM) were classified according to the ICIMD classification system. Genetic diagnoses were assessed against Human Phenotype Ontology terms, gestation of scan findings and literature evidence., Results: 35/302 diagnoses (11.6%) represented IEM. Almost half affected metabolism of complex macromolecules and organelles (n = 16), including congenital disorders of glycosylation (n = 8), peroxisome biogenesis disorders (n = 4), and lysosomal storage disorders (n = 4). There were eight disorders of lipid metabolism and transport, the majority being genes in the cholesterol biosynthesis pathway, eight disorders of intermediary metabolism, of which seven were defects in "energy" processes, and two diagnoses of alkaline phosphatase deficiency., Conclusions: Review of pES diagnoses and ultrasound scan findings is key to understanding genotype-phenotype correlations. IEM are genetically heterogeneous and may present with variable scan findings, which makes an individual diagnosis difficult to suspect. Diagnosis during pregnancy is particularly important for many IEM with respect to prognosis and early neonatal management., (© 2023 John Wiley & Sons Ltd.)

Objective: Health care and health professions education are becoming increasingly global, yet no formal international accrediting body exists for medical education. Among the challenges in developing international standards for medical education is the variation in program models, with some regions offering six-year bachelor's degrees and others, including North America, customarily requiring a bachelor's degree prior to admission to a 4-year graduate-level degree program. This study sought to determine the applicability of the USA Liaison Committee on Medical Education (LCME) accreditation standards internationally as the foundation for program development, quality improvement, and program evaluation in a program that follows the North American medical education model in the United Arab Emirates (UAE)., Methods: Using a qualitative political, economic, sociocultural, technological, legal, and environmental (PESTLE) analysis framework, we systematically assessed the applicability of each of the 93 LCME accreditation elements to the nascent doctor of medicine (MD) degree program at Khalifa University., Results: All 93 elements in the most current LCME accreditation standards were deemed applicable internationally in a program developed in accordance with the North American model of medical education. Of these, three elements were deemed applicable with caveats in the legal or regulatory processes required to achieve comparable compliance outside of the USA. No elements were deemed not applicable in an international setting., Conclusions: Our analysis demonstrates that the LCME accreditation standards are model-specific and can be effectively applied internationally in programs that follow the North American model of medical education. Countries in which no specialized medical education accrediting body exists can apply the LCME standards and achieve international benchmarks of quality in medical education through rigorous self-assessment and continuous quality improvement.

Background: Claimants with chronically painful injuries sustained in motor vehicle accidents (MVAs) undergo assessment and management influenced by insurance and medico-legal processes defined by a biomedical paradigm which is discordant with best evidence. We aim to demonstrate the impact of biopsychosocial factors on post-MVA sequelae which contribute to non-recovery., Methods: This was a retrospective cohort study of medico-legal documents and reports on 300 consecutive claimants referred to a pain medicine physician over 7 years (2012-2018) for assessment of painful musculoskeletal injuries post-MVA. One hundred data items were extracted from the medico-legal documents and reports for each claimant and entered into an electronic database. Post-MVA sequelae were analysed using chi-square analysis (OR >2) for significant associations with demographic, pre-MVA and post-MVA variables. Factors with significant associations were entered into a logistic regression model to determine significant statistical predictors of post-MVA sequelae contributing to non-recovery., Results: The claimants were aged 17 to 80 years (mean age 42 years), and approximately half (53%, n=159) were female. The time from MVA to interview averaged 2.5 years. Widespread pain was present in 18% (n=54), and widespread somatosensory signs implying central sensitisation (OR=9.85, p<.001) was the most significant multivariate association. Long-term opiate use post-MVA (32%) was predicted by pre-MVA sleep disturbance (OR=5.08, p=.001), post-MVA major depressive disorder (MDD) (OR=3.02, p=.003) and long-term unemployment (OR=2.22. p=.007). Approximately half (47%, n=142) required post-MVA support from a psychologist or psychiatrist. Post-traumatic stress disorder (PTSD) was diagnosed by a psychiatrist or psychologist in 20% (n=59), yet early identification of risk of PTSD was rare. Pre-MVA, 89.4% (n=268) were studying or employed. Permanent unemployability post-MVA occurred in 35% (n=104) and was predicted by MDD (OR=3.59, p=.001) and antidepressant use (OR=2.17, p=.005). Major social change post-MVA (70%) was predicted by older age (OR=.966, p=.003), depressive symptoms (OR=3.71, p<.001) and opiate use (OR=2.00, p=.039)., Conclusions: Biomedical factors, including older age, impaired sleep and indicators of widespread central sensitisation, and psychological factors, including stress, anxiety and depression, were the most prominent multivariate associations as statistical predictors of major adverse sequelae contributing to non-recovery for claimants with chronic pain post-MVA., Competing Interests: Declaration of Competing Interest The authors declare no relationships or activities that could appear to have influenced the submitted work., (Copyright © 2022. Published by Elsevier Ltd.)

Background: Neoadjuvant therapy reduces fitness, muscle mass, and quality of life (QOL). For patients undergoing chemotherapy and surgery for esophagogastric cancer, maintenance of fitness is paramount. This study investigated the effect of exercise and psychological prehabilitation on anaerobic threshold (AT) at cardiopulmonary exercise testing (CPET). Secondary endpoints included peak oxygen uptake (peak VO 2 ), skeletal muscle mass, QOL, and neoadjuvant therapy completion., Methods: This parallel-arm randomized controlled trial assigned patients with locally advanced esophagogastric cancer to receive prehabilitation or usual care. The 15-week program comprised twice-weekly supervised exercises, thrice-weekly home exercises, and psychological coaching. CPET was performed at baseline, 2 weeks after neoadjuvant therapy, and 1 week preoperatively. Skeletal muscle cross-sectional area at L3 was analyzed on staging and restaging computed tomography. QOL questionnaires were completed at baseline, mid-neoadjuvant therapy, at restaging laparoscopy, and postoperatively at 2 weeks, 6 weeks and 6 months., Results: Fifty-four participants were randomized (prehabilitation group, n = 26; control group, n = 28). No difference in AT between groups was observed post-neoadjuvant therapy. Prehabilitation resulted in an attenuated peak VO 2 decline {-0.4 [95% confidence interval (CI) -0.8 to 0.1] vs. -2.5 [95% CI -2.8 to -2.2] mL/kg/min; p = 0.022}, less muscle loss [-11.6 (95% CI -14.2 to -9.0) vs. -15.6 (95% CI -18.7 to -15.4) cm 2 /m 2 ; p = 0.049], and improved QOL. More prehabilitation patients completed neoadjuvant therapy at full dose [prehabilitation group, 18 (75%) vs. control group, 13 (46%); p = 0.036]. No adverse events were reported., Conclusions: This study has demonstrated some retention of cardiopulmonary fitness (peak VO 2 ), muscle, and QOL in prehabilitation subjects. Further large-scale trials will help determine whether these promising findings translate into improved clinical and oncological outcomes. Trial Registration ClinicalTrials.gov NCT02950324., (© 2021. Society of Surgical Oncology.)

As the global demand for seafood increases, research into the genetic basis of traits that can increase aquaculture production is critical. The eastern oyster (Crassostrea virginica) is an important aquaculture species along the Atlantic and Gulf Coasts of the United States, but increases in heavy rainfall events expose oysters to acute low salinity conditions, which negatively impact production. Low salinity survival is known to be a moderately heritable trait, but the genetic architecture underlying this trait is still poorly understood. In this study, we used ddRAD sequencing to generate genome-wide single-nucleotide polymorphism (SNP) data for four F2 families to investigate the genomic regions associated with survival in extreme low salinity (<3). SNP data were also used to assess the feasibility of genomic selection (GS) for improving this trait. Quantitative trait locus (QTL) mapping and combined linkage disequilibrium analysis revealed significant QTL on eastern oyster chromosomes 1 and 7 underlying both survival and day to death in a 36-day experimental challenge. Significant QTL were located in genes related to DNA/RNA function and repair, ion binding and membrane transport, and general response to stress. GS was investigated using Bayesian linear regression models and prediction accuracies ranged from 0.48 to 0.57. Genomic prediction accuracies were largest using the BayesB prior and prediction accuracies did not substantially decrease when SNPs located within the QTL region on Chr1 were removed, suggesting that this trait is controlled by many genes of small effect. Our results suggest that GS will likely be a viable option for improvement of survival in extreme low salinity., (© The Author(s) 2021. Published by Oxford University Press on behalf of Genetics Society of America.)

Background: The Doctor of Nursing Practice (DNP) nurse is recognized as a practice scholar in nursing and leadership; moreover, the volume of published scholarship from DNP authors is expanding., Purpose: The aim of this research was to quantify and analyze DNP-authored peer-reviewed journal publications from 2012 through 2018., Methods: This was a descriptive analysis of DNP graduate publications found in the WorldCat database from 2012 through 2018., Results: Nearly 2000 (n = 1903) DNP-authored, peer-reviewed journal publications were extracted. Doctor of Nursing Practice-authored publications increased 136% from 2012 to 2018, including 1059 (56%) with DNP authors as first authors and 494 (26%) from DNP graduate solo authors. There were 1179 collaborative and interprofessional publications (62%)., Conclusions: The findings in this research demonstrate an increase in the number of DNP-authored scholarly publications since 2012. Scholarly publications by DNP authors expand the dissemination of knowledge and offer an avenue to improve health outcomes nationally and globally., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Dystrophinopathies are X-linked diseases, including Duchenne muscular dystrophy and Becker muscular dystrophy, due to DMD gene variants. In recent years, the application of new genetic technologies and the availability of new personalised drugs have influenced diagnostic genetic testing for dystrophinopathies. Therefore, these European best practice guidelines for genetic testing in dystrophinopathies have been produced to update previous guidelines published in 2010.These guidelines summarise current recommended technologies and methodologies for analysis of the DMD gene, including testing for deletions and duplications of one or more exons, small variant detection and RNA analysis. Genetic testing strategies for diagnosis, carrier testing and prenatal diagnosis (including non-invasive prenatal diagnosis) are then outlined. Guidelines for sequence variant annotation and interpretation are provided, followed by recommendations for reporting results of all categories of testing. Finally, atypical findings (such as non-contiguous deletions and dual DMD variants), implications for personalised medicine and clinical trials and incidental findings (identification of DMD gene variants in patients where a clinical diagnosis of dystrophinopathy has not been considered or suspected) are discussed.

Objective: Non-invasive prenatal testing (NIPT) is increasingly being adopted as a screening test in the UK and is currently accessed through certain National Health Service healthcare systems or by private provision. This audit aims to describe reasons for and results of cytogenomic investigations carried out within UK genetic laboratories following an NIPT result indicating increased chance of cytogenomic abnormality ('high-chance NIPT result')., Method: A questionnaire was sent out to 24 genetics laboratories in the UK and completed by 18/24 (75%)., Results: Data were returned representing 1831 singleton pregnancies. A total of 1329 (73%) invasive samples were taken following NIPT results showing a high chance of trisomy 21; this was confirmed in 1305 (98%) of these by invasive sampling. Trisomy 21 was confirmed in >99% of patients who also had high-screen risk results or abnormal scan findings. Amongst invasive samples taken due to NIPT results indicating a high chance of trisomy 18, 84% yielded a compatible result, and this number dropped to 49% for trisomy 13 and 51% for sex chromosomes., Conclusion: In the UK, the majority of patients having invasive sampling for high-chance NIPT results are doing so following an NIPT result indicating an increased chance of common trisomies (92%). In this population, NIPT performs particularly well for trisomy 21, but less well for other indications.

Background: Non-invasive prenatal testing (NIPT) for the detection of foetal aneuploidy through analysis of cell-free DNA (cfDNA) in maternal blood is offered routinely by many healthcare providers across the developed world. This testing has recently been recommended for evaluative implementation in the UK National Health Service (NHS) foetal anomaly screening pathway as a contingent screen following an increased risk of trisomy 21, 18 or 13. In preparation for delivering a national service, we have implemented cfDNA-based NIPT in our Regional Genetics Laboratory. Here, we describe our validation and verification processes and initial experiences of the technology prior to rollout of a national screening service., Methods: Data are presented from more than 1000 patients (215 retrospective and 840 prospective) from 'high- and low-risk pregnancies' with outcome data following birth or confirmatory invasive prenatal sampling. NIPT was by the Illumina Verifi® test., Results: Our data confirm a high-fidelity service with a failure rate of ~0.24% and a high sensitivity and specificity for the detection of foetal trisomy 13, 18 and 21. Secondly, the data show that a significant proportion of patients continue their pregnancies without prenatal invasive testing or intervention after receiving a high-risk cfDNA-based result. A total of 46.5% of patients referred to date were referred for reasons other than high screen risk. Ten percent (76/840 clinical service referrals) of patients were referred with ultrasonographic finding of a foetal structural anomaly, and data analysis indicates high- and low-risk scan indications for NIPT., Conclusions: NIPT can be successfully implemented into NHS regional genetics laboratories to provide high-quality services. NHS provision of NIPT in patients with high-risk screen results will allow for a reduction of invasive testing and partially improve equality of access to cfDNA-based NIPT in the pregnant population. Patients at low risk for a classic trisomy or with other clinical indications are likely to continue to access cfDNA-based NIPT as a private test.

Glacial lake outburst floods (GLOFs) are a major concern in the Himalaya and on the Tibetan Plateau (TP), where several disasters occurring over the past century have caused significant loss of life and damage to infrastructure. This study responds directly to the needs of local authorities to provide guidance on the most dangerous glacial lakes across TP where local monitoring and other risk reduction strategies can subsequently be targeted. Specifically, the study aims to establish a first comprehensive prioritisation ranking of lake danger for TP, considering both the likelihood and possible magnitude of any outburst event (hazard), and the exposure of downstream communities. A composite inventory of 1,291 glacial lakes (>0.1 km 2 ) was derived from recent remote sensing studies, and a fully automated and object assessment scheme was implemented using customised GIS tools. Based on four core determinates of GLOF hazard (lake size, watershed area, topographic potential for ice/rock avalanching, and dam steepness), the scheme accurately distinguishes the high to very high hazard level of 19 out of 20 lakes that have previously generated GLOFs. Notably, 16% of all glacial lakes threaten human settlements, with a hotspot of GLOF danger identified in the central Himalayan counties of Jilong, Nyalam, and Dingri, where the potential trans-boundary threat to communities located downstream in Nepal is also recognised. The results provide an important and object scientific basis for decision-making, and the methodological approach is ideally suited for replication across other mountainous regions where such first-order studies are lacking., (Copyright © 2019 Science China Press. Published by Elsevier B.V. All rights reserved.)

This study tested Context-Dependent Effect (CDE) on face recognition by viewing facial expressions as context and face identity as the target. Three groups were defined - Neutral, Happy and Angry, reflecting the facial expressions of the faces presented at the study phase. At the study phase, participants were presented with 42 color photos of faces for 5 s each. At the test phase, participants were presented with 84 pictures of faces, half of which had been viewed beforehand (old). One-third of the old and new faces displayed the same facial expression shown at study, and the remaining two-thirds had one of the other two expressions. Behavioral results show that consistency of facial expressions between study and test facilitated face recognition (i.e., CDE). Eye-tracking results showed that lengthier focus on a face at the study phase gives the participant an advantage only when the same face is presented again at the test phase. Angry expressions intensify binding more than happy or neutral expressions, resulting in higher costs when changing facial expression between study and test. The theoretical implications of these results in terms of the relationship between facial identity and facial expression are discussed. The practical implications, particularly for eyewitness memory literature, are also discussed., (Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.)

Background: The under-5 mortality rate (U5MR) is an important metric of child health and survival. Country-level estimates of U5MR are readily available, but efforts to estimate U5MR subnationally have been limited, in part, due to spatial misalignment of available data sources (e.g., use of different administrative levels, or as a result of historical boundary changes)., Methods: We analyzed all available complete and summary birth history data in surveys and censuses in six countries (Bangladesh, Cameroon, Chad, Mozambique, Uganda, and Zambia) at the finest geographic level available in each data source. We then developed small area estimation models capable of incorporating spatially misaligned data. These small area estimation models were applied to the birth history data in order to estimate trends in U5MR from 1980 to 2015 at the second administrative level in Cameroon, Chad, Mozambique, Uganda, and Zambia and at the third administrative level in Bangladesh., Results: We found substantial variation in U5MR in all six countries: there was more than a two-fold difference in U5MR between the area with the highest rate and the area with the lowest rate in every country. All areas in all countries experienced declines in U5MR between 1980 and 2015, but the degree varied both within and between countries. In Cameroon, Chad, Mozambique, and Zambia we found areas with U5MRs in 2015 that were higher than in other parts of the same country in 1980. Comparing subnational U5MR to country-level targets for the Millennium Development Goals (MDG), we find that 12.8% of areas in Bangladesh did not meet the country-level target, although the country as whole did. A minority of areas in Chad, Mozambique, Uganda, and Zambia met the country-level MDG targets while these countries as a whole did not., Conclusions: Subnational estimates of U5MR reveal significant within-country variation. These estimates could be used for identifying high-need areas and positive deviants, tracking trends in geographic inequalities, and evaluating progress towards international development targets such as the Sustainable Development Goals.

The corpus callosum (CC) is vulnerable to severe traumatic brain injury (TBI). Social cognition requires integration of non-verbal and verbal information in order to understand social behaviour and may be compromised if the CC is damaged. 17 adults with severe, chronic TBI and 17 control participants underwent structural MRI and Diffusion Tensor Imaging. A region of interest analysis examined fractional anisotropy (FA) and mean diffusivity (MD) across regions of the CC. Performance on The Awareness of Social Inference Test (TASIT): part 1 (emotion recognition) and parts 2 and 3 (social inference), was examined in relation to FA and MD. Across participants, higher genu FA values were related to higher TASIT part 3 scores. Increased splenium FA was associated with better performance for TASIT parts 1-3. There was no association between DTI values and TASIT in the controls alone. In the TBI group, FA of the genu and splenium was correlated with TASIT part 3. The pattern of performance was similar when controlling for non-social cognitive ability. In conclusion, social information is complex and multi-modal requiring inter-hemispheric connection. People with TBI, regardless of focal grey matter injury, may lose social cognitive ability due to trauma related changes to the corpus callosum.

There is a need for short, reliable, sensitive assessment tools to measure social cognition. The Awareness of Social Inference Test (TASIT) is an ecologically valid instrument that uses videos of actors engaged in everyday conversations to assess emotion perception, the ability to detect lies, sarcasm and sincerity, and the ability to judge what others are thinking, intending, feeling, and saying. A recently developed short version of TASIT retains the structure of the original test and its clinical sensitivity. In this paper, we compare TASIT-S performance in healthy adolescents, adults, and older adults as well as the effects of country (U.S.A. and Australia), English familiarity and gender. In this study 616 Australians including 226 adolescents (13-19) and 390 adults aged 20-75 + along with 180 U.S. residents (aged 20-74) completed one, two, or three parts of TASIT-S either face to face (Australians) or on-line (US residents). Results indicated that there were minor differences in TASIT-S performance (Part 3 only) based on country of residence and no significant effects for English familiarity in adolescents (not examined in adults). There were no gender effects. Young and middle aged adults (20-59) tended to perform better than adolescents and older adults on most parts of TASIT-S. In general, TASIT-S scores decreased moderately with advancing age. In conclusion, TASIT-S is a useful screen for social cognitive impairment in English speakers that is appropriate for use from adolescence through to older age. It produces comparable scores in the U.S.A. and Australia.

Once considered an incurable disease, the continuous evolution of technologies and techniques has improved both oncological outcomes and quality of life for patients with rectal cancer. Multiport laparoscopic surgery for rectal cancer is the standard of care in many institutions and countries and is the approach that has been most subjected to controlled trial. Following a number of randomized trials as well as large series and registry reports and several Cochrane reviews, there is no evidence of any oncological disadvantage to laparoscopic surgery compared with the open approach and there is good evidence of improved short-term outcomes and some evidence of improved long-term outcomes. We describe the "standard" approach to multiport, laparoscopic low anterior resection.

For commercial oyster aquaculture, triploidy has significant advantages. To produce triploids, the principal technology uses diploid × tetraploid crosses. The development of tetraploid brood stock for this purpose has been successful, but as more is understood about tetraploids, it seems clear that chromosome instability is a principal feature in oysters. This paper is a continuation of work to investigate chromosome instability in polyploid Crassostrea virginica. We established families between tetraploids-apparently stable (non-mosaic) and unstable (mosaic)-and normal reference diploids, creating triploid groups, as well as tetraploids between mosaic and non-mosaic tetraploids. Chromosome loss was about the same for triploid juveniles produced from either mosaic or non-mosaic tetraploids or from either male or female tetraploids. However, there was a statistically significant difference in chromosome loss in tetraploid juveniles produced from mosaic versus non-mosaic parents, with mosaics producing more unstable progeny. These results confirm that chromosome instability, as manifested in mosaic tetraploids, is of little concern for producing triploids, but it is clearly problematic for tetraploid breeding. Concordance between the results from cytogenetics and flow cytometry was also tested for the first time in oysters, by assessing the ploidy of individuals using both techniques. Results between the two were non-concordant.

A fractionation methodology of fat, oil and grease (FOG) deposits was developed based on the insolubility of fatty acid salts in dichloromethane (DCM) and the relatively high solubility of fatty acids and triglycerides in DCM. Using this method, coupled with spectral analysis, it was shown that fatty acids rather than fatty acid salts were the predominant species in FOG deposits obtained from three metropolitan locations in the United States and that fatty acid triglycerides were either not detected or were present in very small concentrations. This solubility-based fractionation approach also revealed the presence of nitrogen-containing compounds that had not been previously detected in FOG deposits including peptides and (or) proteins. The comparison of the ratios of stearic acid salts to stearic acid versus the ratio of palmitic acid salts to palmitic acid in FOG deposits may indicate that the initial step in FOG deposit formation is the preferential precipitation of stearic acid salts.

The commercial production of triploids, and the creation of tetraploid broodstock to support it, has become an important technique in aquaculture of the eastern oyster, Crassostrea virginica. Tetraploids are produced by cytogenetic manipulation of embryos and have been shown to undergo chromosome loss (to become a mosaic) with unknown consequences for breeding. Our objective was to determine the extent of aneuploidy in triploid progeny produced from both mosaic and non-mosaic tetraploids. Six families of triploids were produced using a single diploid female and crossed with three mosaic and non-mosaic tetraploid male oysters. A second set of crosses was performed with the reciprocals. Chromosome counts of the resultant embryos were tallied at 2-4 cell stage and as 6-hour(h)-old embryos. A significant level of aneuploidy was observed in 6-h-old embryos. For crosses using tetraploid males, aneuploidy ranged from 53% to 77% of observed metaphases, compared to 36% in the diploid control. For crosses using tetraploid females, 51%-71% of metaphases were aneuploidy versus 53% in the diploid control. We conclude that somatic chromosome loss may be a regular feature of early development in triploids, and perhaps polyploid oysters in general. Other aspects of chromosome loss in polyploid oysters are also discussed.

Introduction: Non-invasive prenatal diagnosis (NIPD) makes use of cell-free fetal DNA (cffDNA) in the mother's bloodstream as an alternative to invasive sampling methods such as amniocentesis or CVS, which carry a 0.5-1% risk of fetal loss. We describe a droplet digital PCR (ddPCR) assay designed to inform the testing options for couples whose offspring are at risk of suffering from cystic fibrosis via compound heterozygosity. By detecting the presence or absence of the paternal mutation in the cffDNA, it is possible to predict whether the fetus will be an unaffected carrier (absence) or whether further invasive testing is indicated (presence)., Methods: We selected a family in which the parents were known to carry different mutated CFTR alleles as our test system. NIPD was performed for three of their pregnancies during the first trimester (at around 11-12 weeks of gestation). Taqman probes were designed against an amplicon in exon 11 of the CFTR gene, to quantify the proportion of mutant (ΔF508-MUT; FAM) and normal (ΔF508-NOR; VIC) alleles at position c.1521&#95;1523 of the CFTR gene., Discussion: The assay correctly and unambiguously recognized the ΔF508-MUT CFTR allele in the cffDNA of all three proband fetuses and none of the six unaffected control fetuses. In conclusion, the Bio-Rad QX100 was found to be a cost-effective and technically undemanding platform for designing bespoke NIPD assays.

Oyster species suffer from numerous disease outbreaks, often causing high mortality. Because the environment cannot be controlled, genetic improvement for disease resistance to pathogens is an attractive option to reduce their impact on oyster production. We review the literature on selective breeding programs for disease resistance in oyster species, and the impact of triploidy on such resistance. Significant response to selection to improve disease resistance was observed in all studies after two to four generations of selection for Haplosporidium nelsoni and Roseovarius crassostrea in Crassostrea virginica, OsHV-1 in Crassostrea gigas, and Martelia sydneyi in Saccostrea glomerata. Clearly, resistance in these cases was heritable, but most of the studies failed to provide estimates for heritability or genetic correlations with other traits, e.g., between resistance to one disease and another. Generally, it seems breeding for higher resistance to one disease does not confer higher resistance or susceptibility to another disease. For disease resistance in triploid oysters, several studies showed that triploidy confers neither advantage nor disadvantage in survival, e.g., OsHV-1 resistance in C. gigas. Other studies showed higher disease resistance of triploids over diploid as observed in C. virginica and S. glomerata. One indirect mechanism for triploids to avoid disease was to grow faster, thus limiting the span of time when oysters might be exposed to disease., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Aim: Perineal herniation following abdomino-perineal excision of the rectum (APER) can be debilitating. Repair options include a transabdominal (laparoscopic or open), perineal or a combined approach, but there is no consensus on the optimal technique. We describe a novel laparoscopic two-mesh technique and short- to medium-term outcomes., Method: Six patients underwent this operation between 2008 and 2014. Patients were positioned in a modified Lloyd-Davies position, allowing perineal access, and steep Trendelenburg to aid displacement of small bowel from the pelvis. A polypropylene mesh was shaped, placed over the hernial defect, tacked postero-laterally and sutured antero-laterally to reconstitute the pelvic diaphragm. A second larger mesh (composite) was placed over the first supporting mesh and secured with tacks and sutures, overlapping the hernial defect, preventing small bowel contact with the mesh., Results: The median time from the index operation to presentation of the hernia was 5 months. One patient with dense small bowel adhesions from the primary repair had a combined laparoscopic and perineal approach. The median operating time was 141 min and median length of stay was 3 days. There were no intra-operative complications and no recurrences over a follow-up of 1-76 months., Conclusion: We describe a novel laparoscopic technique for perineal hernia repair following APER with a low recurrence rate in the intermediate term., (Colorectal Disease © 2014 The Association of Coloproctology of Great Britain and Ireland.)

Background: The indoor tanning industry is currently receiving increased attention from policymakers, but this industry has not been well researched. Our study examines economic, demographic, and climate-related variables to better understand variations among North Carolina counties in terms of the number of tanning beds and booths per capita during a recent 3-year period., Methods: This study used regression analysis to estimate the magnitude and statistical significance of correlations between the density of tanning beds and other relevant variables from 2007 through 2009., Results: The number of indoor tanning beds per capita in a county is positively correlated with the county's unemployment rate and with the proportion of the county's population that consists of white females 18-49 years of age; there is also a weakly positive correlation with the number of days per year of hot weather in the county. All else being equal, tanning beds are marginally more common in counties with higher rates of unemployment, with a greater number of days when the temperature exeeds 90 degrees Fahrenheit, and with residents who are more likely to engage in risky behaviors (as measured by the gonorrhea infection rate and the percentage of the population who smoke cigarettes)., Limitations: The data span a 3-year period (2007-2009) during which economic conditions were depressed., Conclusion: Economic, demographic, geographic, and climate-related factors should be considered when policies that affect the tanning industry in North Carolina are being developed and implemented.

Chromosomal abnormalities are a significant cause of pregnancy loss. Solid tissue fetal and neonatal pathology samples are routinely examined by karyotype analysis after cell culture. However, there is a high failure rate, and this approach is expensive and labor intensive. We have therefore evaluated a new molecular strategy involving quantitative fluorescent polymerase chain reaction (QF-PCR) and subtelomere multiplex ligation-dependent probe amplification (MLPA) analysis. A retrospective audit showed that less than 4% of abnormal cases may not be detected by this molecular strategy. We validated this strategy in parallel with cytogenetic analysis on 110 patient samples, which included cases of fetal loss, still birth, neonatal death, termination of pregnancy, recurrent miscarriage, and sudden unexpected death in infancy. This validation showed that 55 of the 57 samples that gave a result for both strategies were concordant. During the 1st year of diagnostic testing, we analyzed 382 samples by the molecular strategy. A 16% abnormality rate was observed. These included trisomies 13, 18, 21, monosomy X, and triploidy detected by QF-PCR (77%), and 23% were other trisomies and subtelomere imbalances detected by MLPA. This strategy had a 92% success rate in contrast to the 20%-30% failure rate observed with cell culture and cytogenetic analysis. We conclude that QF-PCR and subtelomere MLPA is a suitable strategy for analysis of the majority of fetal and neonatal pathology samples, with many advantages over conventional cytogenetic analysis.

Circulating ghrelin elevates abdominal adiposity by a mechanism independent of its central orexigenic activity. In this study we tested the hypothesis that peripheral ghrelin induces a depot-specific increase in white adipose tissue (WAT) mass in vivo by GH secretagogue receptor (GHS-R(1a))-mediated lipolysis. Chronic iv infusion of acylated ghrelin increased retroperitoneal and inguinal WAT volume in rats without elevating superficial sc fat, food intake, or circulating lipids and glucose. Increased retroperitoneal WAT mass resulted from adipocyte enlargement probably due to reduced lipid export (ATP-binding cassette transporter G1 mRNA expression and circulating free fatty acids were halved by ghrelin infusion). In contrast, ghrelin treatment did not up-regulate biomarkers of adipogenesis (peroxisome proliferator-activated receptor-gamma2 or CCAAT/enhancer binding protein-alpha) or substrate uptake (glucose transporter 4, lipoprotein lipase, or CD36) and although ghrelin elevated sterol-regulatory element-binding protein 1c expression, WAT-specific mediators of lipogenesis (liver X receptor-alpha and fatty acid synthase) were unchanged. Adiposity was unaffected by infusion of unacylated ghrelin, and the effects of acylated ghrelin were abolished by transcriptional blockade of GHS-R(1a), but GHS-R(1a) mRNA expression was similar in responsive and unresponsive WAT. Microarray analysis suggested that depot-specific sensitivity to ghrelin may arise from differential fine tuning of signal transduction and/or lipid-handling mechanisms. Acylated ghrelin also induced hepatic steatosis, increasing lipid droplet number and triacylglycerol content by a GHS-R(1a)-dependent mechanism. Our data imply that, during periods of energy insufficiency, exposure to acylated ghrelin may limit energy utilization in specific WAT depots by GHS-R(1a)-dependent lipid retention.

Autosomal dominant polycystic kidney disease (ADPKD) is estimated to affect 1/600-1/1000 individuals worldwide. The disease is characterized by age dependent renal cyst formation that results in kidney failure during adulthood. Although ultrasound imaging may be an adequate diagnostic tool in at risk individuals older than 30, this modality may not be sufficiently sensitive in younger individuals or for those from PKD2 families who have milder disease. DNA based assays may be indicated in certain clinical situations where imaging cannot provide a definitive clinical diagnosis. The goal of this study was to evaluate the utility of direct DNA analysis in a test sample of 82 individuals who were judged to have polycystic kidney disease by standard clinical criteria. The samples were analyzed using a commercially available assay that employs sequencing of both genes responsible for the disorder. Definite disease causing mutations were identified in 34 (approximately 42%) study participants. An additional 30 (approximately 37%) subjects had either in frame insertions/deletions, non-canonical splice site alterations or a combination of missense changes that were also judged likely to be pathogenic. We noted striking sequence variability in the PKD1 gene, with a mean of 13.1 variants per participant (range 0-60). Our results and analysis highlight the complexity of assessing the pathogenicity of missense variants particularly when individuals have multiple amino acid substitutions. We conclude that a significant fraction of ADPKD mutations are caused by amino acid substitutions that need to be interpreted carefully when utilized in clinical decision-making.

Objectives: QF-PCR analysis can be used as a rapid test to diagnose primary trisomy in prenatal samples. Mosaicism in CVS detected by QF-PCR has previously been reported; however, no case has so far been reported in which the QF-PCR result was completely discrepant to that of the karyotype analysis from a long-term culture., Methods: A CVS, referred because of a high serum screening risk of 1:10 for Down Syndrome and 1:110 for Edwards Syndrome, was tested by QF-PCR analysis and chromosome analysis of cultured cells. Subsequent analyses were carried out on a follow-up amniotic fluid sample and foetal tissue samples., Results: Conflicting results were obtained between QF-PCR analysis on two independent fronds from the chorionic villi and chromosome analysis on cultured CVS. Cytogenetic and molecular analysis on a subsequent amniotic fluid sample indicated trisomy 18 with no evidence of mosaicism. Analysis of follow-up tissue confirmed trisomy in a foetal skin sample and mosaicism for trisomy 18 in four placental sites tested., Conclusion: We report here an apparently normal CVS QF-PCR result that was completely discrepant with the trisomy 18 positive karyotype result on long-term culture. This has important implications regarding our current testing protocol., (2006 John Wiley & Sons, Ltd.)

The availability of tetraploid Pacific oysters provides a unique opportunity for comparative studies of sperm cryopreservation between diploids and tetraploids. In parallel to studies with sperm from diploid oysters, this study reports systematic factor optimization for sperm cryopreservation of tetraploid oysters. Specifically, this study evaluated the effects of cooling rate, single or combined cryoprotectants at various concentrations, equilibration time (exposure to cryoprotectant), and straw size. Similar to sperm from diploids, the optimal cooling rate was 5 degrees C/min to -30 degrees C, followed by cooling at 45 degrees C/min to -80 degrees C before plunging into liquid nitrogen. Screening of single or combined cryoprotectants at various concentrations showed that a combination of the cryoprotectants 6% polyethylene glycol/4% propylene glycol and 6% polyethylene glycol/4% dimethyl sulfoxide yielded consistently high post-thaw motility. A long equilibration (60 min) yielded higher percent fertilization, and confirmed that extended equilibration could be beneficial when low concentrations of cryoprotectant are used. There was no significant difference in post-thaw motility between straw sizes of 0.25 and 0.5 mL. Despite low post-thaw fertilization (<10%) in general for sperm from tetraploids, optimized protocols in the present study effectively retained post-thaw motility for sperm from tetraploid oysters. This study confirmed that sperm from tetraploid Pacific oysters were more negatively affected by cryopreservation than were those of diploids. One possible explanation is that sperm from these two ploidies are different in their plasma membrane properties (e.g., structure, permeability, and elasticity), and the plasma membrane of sperm from tetraploids is more sensitive to cryopreservation effects. The fact that combinations of non-permeating and permeating cryoprotectants improved post-thaw motility in sperm from tetraploids provided presumptive evidence for this interpretation.

Genetic variation in wild Asian populations and U.S. hatchery stocks of Crassostrea ariakensis was examined using polymerase chain reactions with restriction fragment length polymorphism (PCR-RFLP) analysis of both the mitochondrial COI gene and the nuclear internal transcribed spacer (ITS) 1 region and using 3 microsatellite markers. Hierarchical analysis of molecular variance and pairwise comparisons revealed significant differentiation (P < 0.05) between samples from the northern region, represented by collections from China and Japan, and 2 of 3 samples from southern China. PCR-RFLP patterns were identified that were diagnostic for the northern (N-type) and southern (S-type) groups. Microsatellite marker profiles were used to assign each oyster to one of the two northern or two southern populations. Results for more than 97% of the oysters were consistent with the PCR-RFLP patterns observed for each individual in that oysters with N-type patterns were assigned to one of the northern populations and those with S-type patterns to one of the southern populations. At one site of the Beihai (B) region in southern China a mix of individuals with either the N-type or S-type PCR-RFLP genotypes was found. No heterozygotes at the nuclear ITS-1 locus were found in the sample, possibly indicating reproductive isolation in sympatry. Microsatellite assignment test results of the B individuals were also consistent with identifications as either the N-type or S-type based on PCR-RFLP patterns. The parental population for one hatchery stock was this B sample, which initially was composed of almost equal numbers of northern and southern genetic types. After hatchery spawns, however, more than 97% of the progeny fell into the northern genetic group by PCR-RFLP and microsatellite assignment test analyses, indicating that the individuals with the southern genotype contributed little to the spawn, owing to gametic incompatibility, differential larval survival, or a difference in timing of sexual maturity. Overall, results suggested that oysters collected as C. ariakensis in this study, and likely in other studies as well, include two different sympatric species with some degree of reproductive isolation.

Cryopreservation of sperm from tetraploid organisms (the possession of four chromosome sets) is essentially unexplored. This is the first cryopreservation study to address sperm from tetraploid Pacific oysters, Crassostrea gigas, and addresses the commercial production of triploid oysters (three chromosome sets). Initial motility, refrigerated storage of undiluted sperm, osmolality of extender solutions, sperm concentrations, equilibration time, and cryoprotectants of propylene glycol and dimethyl sulfoxide were evaluated with sperm from diploid and tetraploid oysters. Unlike most teleost fishes, in which the duration of active motility is typically brief, the motility of sperm from oysters lasts for hours. The present study showed that responses to treatment effects by sperm from tetraploids were different from diploids. The majority of tetraploid experiments resulted in less than 10% motility after thawing and less than 5% fertilization. The highest fertilization obtained for thawed sperm was 96% for sperm from diploid oysters and 28% for sperm from tetraploid oysters. Differential responses to treatments by sperm from tetraploid and diploid oysters may be due to differences in gonadal development. However, the use of cryopreserved sperm from tetraploid Pacific oysters produced 100% triploid offspring by fertilization of eggs from diploid females as determined by flow cytometry of larvae. This study demonstrates that sperm from tetraploid oysters can be collected, frozen, and stored for production of triploid offspring.

Eighteen microsatellite markers were developed for the Crassostrea virginica nuclear genome, including di-, tri-, and tetranucleotide microsatellite repeat regions that included perfect, imperfect, and compound repeat sequences. A reference panel with DNA from the parents and four progeny of 10 full-sib families was used for a preliminary confirmation of polymorphism at these loci and indications of null alleles. Null alleles were discovered at three loci; in two instances, primer redesign enabled their amplification. Two to five representative alleles from each locus were sequenced to ensure that the targeted loci were amplifying. The sequence analysis revealed not only variation in the number of simple sequence repeat units, but also polymorphisms in the microsatellite flanking regions. A total of 3626 bp of combined microsatellite flanking region from the 18 loci was examined, revealing indels as well as nucleotide site substitutions. Overall, 16 indels and 146 substitutions were found with an average of 4.5% polymorphism across all loci. Eight markers were tested on the parents and 39-61 progeny from each of four families for examination of allelic inheritance patterns and genotypic ratios. Twenty-six tests of segregation ratios revealed eight significant departures from expected Mendelian ratios, three of which remained significant after correction for multiple tests. Deviations were observed in both the directions of heterozygote excess and deficiency.

Loss of function after SCI, ABI or stroke has a marked affect on ones quality of life. Return of function has been a long-standing goal of physical and occupational therapy. Repeated motor practice has been identified as crucial for motor recovery. The development of a robotic device for neuromotor rehabilitation and upper extremity neuromuscular system recovery is described. The actuator mechanism allows free motion when possible, and provides programmable therapeutic levels of resistance. The sensor system allows characterization of the applied forces, and accurate measurement of the range of motion of the joint. The control system provides real time feedback of actuator commands based on sensor data, calibration routines, and operational modes.

Although largely considered a problem of developing countries today, trachoma was once extremely common in parts of the United States and accounted for a large proportion of blindness. Under an act signed by President Woodrow Wilson in June 1913, a substantial part of the U.S. Public Health Service budget was earmarked to fight trachoma. Numerous trachoma surveys revealed the presence of a "trachoma belt" across the mid United States, and the prevalence of trachoma reached as high as 50-90% among school children on some Indian reservations. Crowding, poverty, and lack of clean water and hygiene were identified as risk factors for trachoma. Measures taken to combat trachoma included isolation schools for infected children, special government trachoma hospitals and field clinics, screening of immigrants to the U.S., improvements in hygiene and sanitation, and antibiotic therapy. The Indian Health Service utilized radical eyelid surgery with reportedly disastrous consequences. Prevalence surveys show a clear decline in trachoma in the U.S. during the twentieth century.

We report the development of a new 'photochemical titration' actinometric method for measurement of UV-B (290-320 nm) and UV-A (320-400 nm) light dose during drug photostability testing. It is based upon photolysis of aqueous 2-nitrobenzaldehyde solution, a well-characterized reaction that has been previously demonstrated to be useful as an accurate and reliable actinometric method. Our new method can be performed by a chemical technician using only common reagents. It has been developed for use with xenon arc lamp illumination chambers which are commonly employed for drug photostability testing, but can be readily modified for use with the other illumination sources.

Chewing lice, Geomydoecus and Thomomydoecus, coexist on pocket gophers, Thomomys spp. We investigated the spatial distribution of the 2 genera on their hosts and explored possible mechanisms of resource partitioning by chewing lice. Chewing lice appear to partition available host resources spatially, with Geomydoecus occurring primarily on the lateral and dorsal regions of the host, and Thomomydoecus occurring primarily on the lateral and ventral regions. Although spatial partitioning of the host habitat is evident, it does not appear to be explained by hair diameter. Spatial partitioning of the host's body could be the result of some other factor, possibly temperature or humidity gradients of the host's body.

The dynamics of polar body release are important for creating polyploid shellfish. For producing triploids, these dynamics concern meiosis in diploid eggs and are well understood. For creating tetraploids, eggs from triploids are employed and the dynamics, variation, and environmental influences upon polar body release are less studied. We investigated the effects of several agents on the timing of 50% first polar body (PB1) release in eggs of triploids. PB1 release is generally slower in triploid eggs than diploid ones at 26 degrees C. Lowering the temperature (from 26 to 19 degrees C) had a marked effect on timing of 50% PB1 in both diploid and triploid eggs. While lower temperature merely slowed development in diploid eggs, it nearly halted it in triploid eggs. At any temperature, the variability in 50% PB1 release was much higher in triploid eggs than diploid ones; this variation occurred both within eggs from individual females and among eggs from different females. The amount of time eggs remain in seawater between the time they are stripped and fertilized (or time of hydration) also affected rate of meiosis. In triploid eggs, the average time necessary for the expulsion of 50% PB1 was 23 min post-fertilization (PF) for 75 min of hydration versus 29 min PF for 35 min. However, increasing the time of hydration had no effect on the variability in the timing among females. Serotonin also had no effect on the dynamics of polar body release in triploids. Variability among triploid females in timing of meiosis cannot be improved with any treatments we tried. Consequently we recommend that treatments of triploid eggs to produce tetraploids incorporate a single female at a time.

A unique feature of sex in Crassostrea oysters is the coexistence of protandric sex change, dioecy, and hermaphroditism. To determine whether such a system is genetically controlled, we analyzed sex ratios in 86 pair-mated families of the Pacific oyster, Crassostrea gigas Thunberg. The overall female ratios of one-, two-, and three-year-old oysters were 37%, 55%, and 75%, respectively, suggesting that a significant proportion of oysters matured first as males and changed to females in later years. Detailed analysis of sex ratios in factorial and nested crosses revealed significant paternal effects, which corresponded to two types of sires. No major maternal effects on sex were observed. Major genetic control of sex was further indicated by the distribution of family sex ratios in two to four apparently discreet groups. These and other data from the literature are compatible with a single-locus model of primary sex determination with a dominant male allele (M) and a protandric female allele (F), so that MF are true males and FF are protandric females that are capable of sex change. The rate of sex change of FF individuals may be influenced by secondary genes and/or environmental factors. Strong maternal and weak paternal effects on sexual maturation or time of spawning were also suggested., (© 1998 The Society for the Study of Evolution.)

Chromosome segregation in fertilized eggs from triploid Pacific oysters, following inhibition of the first polar body (PB1), was studied with acetic orcein staining techniques. To block the release of PB1, fertilized eggs were treated with 0.5 mg/l of cytochalasin B (CB). Four types of segregation were observed, namely, "tripolar segregation" (54.5%), "united bipolar segregation" (12%), "separated bipolar segregation" (2.5%), and "incomplete united bipolar segregation" (4%). The remaining 23% could not be classified because of chromosome disorganization, but appeared to be variants of the above. It seemed clear that the predominant pattern that gave rise to tetraploids was united bipolar segregation, although certain separated bipolar segregations might also lead to the formation of tetraploids. The sequential events of meioses observed in CB-treated eggs are described. The asynchrony of meiotic events and possible mechanisms for the various types of chromosome segregation are discussed.

Use of the fragrance 6-methylcoumarin (6-MC) in cosmetic products has declined significantly due to numerous reports of photoallergic contact dermatitis associated with its use. We have determined that 6-MC undergoes direct photolysis with an estimated half-life of 83 minutes when illuminated with mid-latitude U.S., noon-centered, equinox sunlight and a quantum yield for photolysis at 313 nm of phi = 3 x 10(-3). The work presented here also provides evidence that singlet molecular oxygen ((1)O2) is formed in illuminated solutions containing 6-MC. An estimated value of phi = 0.01 is reported for the (1)O2 quantum yield at 313 nm. Formation of (1)O2 is significant because it is known to react with a variety of biomolecules and it is possible that (1)O2 formation is at least partially responsible for reports of 6-MC photoallergenicity and phototoxicity.

Sex and meiosis were studied in induced autotetraploids of the Pacific oyster (Crassostrea gigas Thunberg) and were compared with sex and meiosis in autotriploids and normal diploids. Tetraploid oysters reached sexual maturity at 1 year of age in an approximately 1:1 sex ration. In contrast with the abnormally high frequency of hermaphrodites among triploids, tetraploids had about the same level of hermaphrodites as normal diploids. Fecundity of tetraploids was comparable to that of normal diploids, differing from the greatly reduced fecundity of triploids. Homologous chromosomes synapsed predominantly as trivalents in eggs from triploids and as quadrivalents in eggs from tetraploids. After fertilization, eggs from tetraploids and triploids went through two meiotic divisions, as normal eggs did. The average gamete chromosome number was 10.0 for diploids and 19.9 for tetraploids. The distribution of gamete chromosome numbers from triploids suggested that the extra chromosome in the trivalent segregated randomly during anaphase I. In tetraploids, however, the two extra chromosomes in the quadrivalents did not segregate independently and, instead, they preferentially cosegregated to opposite poles producing balanced gametes. These results suggest that mechanisms may exist to weight, balance, and equally distribute quadrivalents, possibly through mitotic force and tension. Errors in chromosome balancing in normal meiosis may result in nondisjunction, which is the primary cause of human aneuploidy.

In gene mapping, the genetic distance between two genes is measured by the frequency of meiotic crossovers occurring between them. It is generally assumed that there is more than one crossover per chromosome, and the distribution of crossovers along chromosomes is random and follows a Poisson distribution (no interference), or that interference is inversely correlated with distance. Although those assumptions may be correct for some organisms, we report here a novel exception in the marine mollusc Mulinia lateralis Say. Using segregation analysis of gynogenetic diploids, we found surprisingly high gene-centromere recombinant frequencies for most of the 13 allozyme loci studied. For at least six loci, there was always one and only one crossover occurring between the gene and its centromere, suggesting complete interference where the occurrence of one crossover completely suppressed the occurrence of another. The complete interference was confirmed by the cytogenetic observation that there was only one chiasma for all bivalents. Further, sites of the single crossover seem not to be randomly distributed along chromosomes, but preferentially located in a recombination hot-region proximal to the centromere. The restricted distribution of a single crossover per chromosome provides one explanation for the unique phenomenon of heterozygote deficiency in M. lateralis and other molluscs.

A pantropic pseudotyped retroviral vector containing the envelope protein of vesicular stomatitis virus was used as a gene transfer vector in the dwarf surfclam, Mulinia lateralis. These pantropic retroviral vectors have an extremely broad host cell range and can infect many nonmammalian species. Newly fertilized dwarf surfclam eggs were electroporated at 700 V in the presence of 1 x 10(4) colony-forming units of pantropic pseudotyped retroviral particles. Infection was well tolerated and did not affect the survival rate of the embryos. Gametes collected from P1 presumptive transgenic animals were analyzed for the presence of provirus by PCR, and in different experiments 13-33% of the gamete pools were positive for the transgene. Dot blot hybridization of DNA samples from the F1 offspring of two different crosses between infected P1 and wild-type individuals revealed that 28% and 31% of F1 offspring were transgenic, respectively. Southern blot analysis of DNA isolated from PCR-positive F1 animals confirmed integration of a single copy of the provirus into the host genome. Thus, the germ lines of these two P1 transgenic animals were mosaic for the transgene. Expression of beta-galactosidase encoded by the provirus was detected in transgenic but not control surfclam embryos. Pantropic pseudotyped retroviral vectors provide a useful method for the stable introduction of foreign genetic information into surfclams and may facilitate the introduction of desirable genetic traits into commercially important shellfish and crustaceans.

Evidence is presented for the photochemical formation of singlet molecular oxygen (1O2) in air-saturated aqueous solutions of several sunscreen active ingredients using sunlight-range illumination. This is of significance because (1) 1O2 is known to be cytotoxic, and (2) there have been several reports of toxic effects associated with the use of some sunscreens; most notably, with p-aminobenzoic acid (PABA). Illuminated aqueous solutions of PABA, 2-ethylhexyl p-(dimethylamino)benzate (ODPABA), 2-hydroxy-4-methoxybenzophenone (BZ3), 2,2'-dihydroxy-4-methoxybenzophenone (BZ8), 2-ethylhexyl 2-cyano-3,3-diphenylacrylate (OCR), 2-ethylhexyl p-methoxycinnamate (OMC), and 2-ethylhexyl salicylate (OCS) were evaluated individually for 1O2 formation. Furfuryl alcohol (FFA), a well-known chemical trap for 1O2, was added to each of the aqueous sunscreen solutions. The FFA was consumed when solutions of PABA, ODPABA, OMC, and OCR were illuminated, but no loss of FFA other than by direct photolysis occurred in solutions of BZ3, BZ8, or OCS. There was also no significant loss of FFA in any of these solutions kept in the dark. Further evidence for the formation of 1O2 in illuminated aqueous sunscreen solutions is provided by the results of experiments in which individual solutions containing sunscreen active ingredients and FFA that were diluted with D2O exhibited an increased rate of FFA consumption while the addition of azide ion (N3-) reduced the rate of FFA consumption. Continuous sunlight-range illumination of aqueous PABA solutions produced significantly higher steady-state concentrations of 1O2 than in solutions containing any of the other sunscreen active ingredients evaluated. The substituted benzophenone compounds (BZ3 and BZ8) and the salicylate-based compound (OCS) not only appear to produce no 1O2, but they also appear to produce no other reactive oxidant species that are capable of consuming FFA. This indicates that BZ3, BZ8, and OCS may be peferable, from the standpoint of toxic oxidant formation, for use as sunscreen active ingredients when compared to the other compounds evaluated in this study.