DNA methylation signatures of early-life adversity are exposure-dependent in wild baboons

The early-life environment can profoundly shape the trajectory of an animal's life, even years or decades later. One mechanism proposed to contribute to these early-life effects is DNA methylation. However, the frequency and functional importance of DNA methylation in shaping early-life effects on adult outcomes is poorly understood, especially in natural populations. Here, we integrate prospectively collected data on fitness-associated variation in the early environment with DNA methylation estimates at 477,270 CpG sites in 256 wild baboons. We find highly heterogeneous relationships between the early-life environment and DNA methylation in adulthood: aspects of the environment linked to resource limitation (e.g., low-quality habitat, early-life drought) are associated with many more CpG sites than other types of environmental stressors (e.g., low maternal social status). Sites associated with early resource limitation are enriched in gene bodies and putative enhancers, suggesting they are functionally relevant. Indeed, by deploying a baboon-specific, massively parallel reporter assay, we show that a subset of windows containing these sites are capable of regulatory activity, and that, for 88% of early drought-associated sites in these regulatory windows, enhancer activity is DNA methylation-dependent. Together, our results support the idea that DNA methylation patterns contain a persistent signature of the early-life environment. However, they also indicate that not all environmental exposures leave an equivalent mark and suggest that socioenvironmental variation at the time of sampling is more likely to be functionally important. Thus, multiple mechanisms must converge to explain early-life effects on fitness-related traits.

3-Year Outcomes From the Amplatzer Amulet Left Atrial Appendage Occluder Randomized Controlled Trial (Amulet IDE)

BACKGROUND

The Amulet (Abbott) left atrial appendage occluder investigational device exemption trial is the largest randomized trial evaluating the safety and effectiveness of the Amulet left atrial appendage occluder compared with the Watchman 2.5 device (Boston Scientific) through 5 years.

OBJECTIVES

This analysis evaluated the device effect on 3-year outcomes in the Amulet investigational device exemption trial.

METHODS

The medication regimen and key clinical outcomes were reported through 3 years including: 1) the composite of ischemic stroke or systemic embolism (SE); 2) the composite of all strokes, SE, or cardiovascular (CV) death; 3) major bleeding; and 4) all-cause death and CV death.

RESULTS

A total of 1,878 patients at 108 sites were randomized. A significantly higher percentage of patients were free of oral anticoagulation usage at 3 years with Amulet (96.2%) vs Watchman (92.5%) (P < 0.01). Clinical outcomes were comparable for the composite of ischemic stroke or SE (5.0% vs 4.6%; P = 0.69); the composite of all strokes, SE, or CV death (11.1% vs 12.7%; P = 0.31); major bleeding (16.1% vs 14.7%; P = 0.46); all-cause death (14.6% vs 17.9%; P = 0.08); and CV death (6.6% vs 8.5%; P = 0.14) for Amulet and Watchman, respectively. Through 3 years, device factors (device-related thrombus or peridevice leak ≥3 mm) preceded ischemic stroke events and CV deaths more frequently in Watchman compared with Amulet patients.

CONCLUSIONS

The Amulet occluder demonstrated continued safety and effectiveness with over 96% free of oral anticoagulation usage through 3 years in a high-risk population compared to the Watchman device. (AMPLATZER Amulet LAA Occluder Trial [Amulet IDE]; NCT02879448).

Mechanisms, predictors, and evolution of severe peri-device leaks with two different left atrial appendage occluders

AIMS

Incomplete left atrial appendage occlusion (LAAO) due to peri-device leak (PDL) is a limitation of the therapy. The Amulet IDE trial is the largest randomized head-to-head trial comparing the Amulet and Watchman 2.5 LAAO devices with fundamentally different designs. The predictors and mechanistic factors impacting differences in PDLs within the Amulet IDE trial are assessed in the current analysis.

METHODS AND RESULTS

An independent core lab analysed all images for the presence or absence of severe PDL (>5 mm). The incidence, mechanistic factors, predictors using propensity score-matched controls, and evolution of severe PDLs through 18 months were assessed. Of the 1878 patients randomized in the trial, the Amulet occluder had significantly fewer severe PDLs than the Watchman device at 45 days (1.1 vs. 3.2%, P < 0.001) and 12 months (0.1 vs. 1.1%, P < 0.001). Off-axis deployment or missed lobes were leading mechanistic PDL factors in each device group. Larger left atrial appendage (LAA) dimensions including orifice diameter, landing zone diameter, and depth predicted severe PDL with the Watchman device, with no significant anatomical limitations noted with the Amulet occluder. Procedural and device implant predictors were found with the Amulet occluder attributed to the learning curve with the device. A majority of Watchman device severe PDLs did not resolve over time through 18 months.

CONCLUSION

The dual-occlusive Amplatzer Amulet LAA occluder provided improved LAA closure compared with the Watchman 2.5 device. Predictors and temporal observations of severe PDLs were identified in the Amulet IDE trial.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov Unique identifier NCT02879448.

DNA methylation signatures of early life adversity are exposure-dependent in wild baboons

The early life environment can profoundly shape the trajectory of an animal's life, even years or decades later. One mechanism proposed to contribute to these early life effects is DNA methylation. However, the frequency and functional importance of DNA methylation in shaping early life effects on adult outcomes is poorly understood, especially in natural populations. Here, we integrate prospectively collected data on fitness-associated variation in the early environment with DNA methylation estimates at 477,270 CpG sites in 256 wild baboons. We find highly heterogeneous relationships between the early life environment and DNA methylation in adulthood: aspects of the environment linked to resource limitation (e.g., low-quality habitat, early life drought) are associated with many more CpG sites than other types of environmental stressors (e.g., low maternal social status). Sites associated with early resource limitation are enriched in gene bodies and putative enhancers, suggesting they are functionally relevant. Indeed, by deploying a baboon-specific, massively parallel reporter assay, we show that a subset of windows containing these sites are capable of regulatory activity, and that, for 88% of early drought-associated sites in these regulatory windows, enhancer activity is DNA methylation-dependent. Together, our results support the idea that DNA methylation patterns contain a persistent signature of the early life environment. However, they also indicate that not all environmental exposures leave an equivalent mark and suggest that socioenvironmental variation at the time of sampling is more likely to be functionally important. Thus, multiple mechanisms must converge to explain early life effects on fitness-related traits.

Selection against admixture and gene regulatory divergence in a long-term primate field study

Genetic admixture is central to primate evolution. We combined 50 years of field observations of immigration and group demography with genomic data from ~9 generations of hybrid baboons to investigate the consequences of admixture in the wild. Despite no obvious fitness costs to hybrids, we found signatures of selection against admixture similar to those described for archaic hominins. These patterns were concentrated near genes where ancestry is strongly associated with gene expression. Our analyses also show that introgression is partially predictable across the genome. This study demonstrates the value of integrating genomic and field data for revealing how "genomic signatures of selection" (e.g., reduced introgression in low-recombination regions) manifest in nature; moreover, it underscores the importance of other primates as living models for human evolution.

Distinct gene regulatory signatures of dominance rank and social bond strength in wild baboons

The social environment is a major determinant of morbidity, mortality and Darwinian fitness in social animals. Recent studies have begun to uncover the molecular processes associated with these relationships, but the degree to which they vary across different dimensions of the social environment remains unclear. Here, we draw on a long-term field study of wild baboons to compare the signatures of affiliative and competitive aspects of the social environment in white blood cell gene regulation, under both immune-stimulated and non-stimulated conditions. We find that the effects of dominance rank on gene expression are directionally opposite in males versus females, such that high-ranking males resemble low-ranking females, and vice versa. Among females, rank and social bond strength are both reflected in the activity of cellular metabolism and proliferation genes. However, while we observe pronounced rank-related differences in baseline immune gene activity, only bond strength predicts the fold-change response to immune (lipopolysaccharide) stimulation. Together, our results indicate that the directionality and magnitude of social effects on gene regulation depend on the aspect of the social environment under study. This heterogeneity may help explain why social environmental effects on health and longevity can also vary between measures. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.

Sparrows and supergenes: Ecological epigenetics in action

Despite the promise of ecological epigenetics, there remain few cases that clearly link epigenetic variation in wild animal populations to evolutionary change. In this issue of Molecular Ecology, Sun et al. provide such an example in white-throated sparrows-a fascinating system in which a large chromosomal rearrangement generates a "supergene" polymorphism linked to plumage colour, aggression and parenting behaviour. By combining whole genome bisulphite sequencing with RNA-sequencing and chromatin accessibility data, they show that the two alleles of this chromosomal polymorphism also exhibit substantial differences in DNA methylation levels, with implications for gene expression and transposable element activity. Their results provide a compelling case study for how genetic and epigenetic evolution proceed in concert. They also demonstrate the importance of integrating multiple types of genomic information to understand how gene regulation evolves, providing a model for future work in nonmodel species.

High social status males experience accelerated epigenetic aging in wild baboons

Aging, for virtually all life, is inescapable. However, within populations, biological aging rates vary. Understanding sources of variation in this process is central to understanding the biodemography of natural populations. We constructed a DNA methylation-based age predictor for an intensively studied wild baboon population in Kenya. Consistent with findings in humans, the resulting 'epigenetic clock' closely tracks chronological age, but individuals are predicted to be somewhat older or younger than their known ages. Surprisingly, these deviations are not explained by the strongest predictors of lifespan in this population, early adversity and social integration. Instead, they are best predicted by male dominance rank: high-ranking males are predicted to be older than their true ages, and epigenetic age tracks changes in rank over time. Our results argue that achieving high rank for male baboons - the best predictor of reproductive success - imposes costs consistent with a 'live fast, die young' life-history strategy.

Adult Plant Leaf Rust Resistance in AC Taber Wheat Maps to Chromosomes 2BS and 3BS

AC Taber is a hard red spring wheat cultivar that has had long-lasting resistance to the leaf rust fungus Puccinia triticina. The objective of this study was to determine the chromosome location of the leaf rust resistance genes in AC Taber. The leaf rust-susceptible cultivar Thatcher was crossed with AC Taber to develop an F₆ recombinant inbred line (RIL) population. The RILs and parents were evaluated for segregation of leaf rust resistance in five field plot tests and in two seedling tests to race BBBDB of P. triticina. A genetic map of the RIL population was developed using 90,000 single nucleotide polymorphism markers with the Illumina Infinium iSelect 90K wheat bead array. Quantitative trait loci (QTLs) with significant effects for lower leaf rust severity in the field plot tests were found on chromosomes 2BS and 3BS. The same QTLs also had significant effects for lower infection type in seedlings to leaf rust race BBBDB. The gene on 2BS was the adult plant resistance gene Lr13, and the gene on 3BS mapped to the same region as the adult plant resistance gene Lr74 and other QTLs for leaf rust resistance. Kompetitive allele-specific PCR assay markers linked to the 2BS and 3BS regions were developed and should be useful for marker-based selection of these genes.

Behavioral mimicry predicts social favor in adolescent rhesus macaques (Macaca mulatta)

Non-conscious mimicry is a highly conserved component of animal behavior with multifaceted connections to sociality across taxa. One intriguing consequence of this mimicry in primates is that it promotes positive social feedback from the recipient toward the mimicker. This suggests that mimicry in primates may be an important aspect of positive social interaction, but few studies have tracked the consequences of mimicry in naturally occurring complex social conditions. Here, we designed a novel ethogram to characterize mimicry between conspecifics, to better understand whether mimicry is associated with affiliation between primates in a semi-naturalistic captive setting. In this study, 15 juvenile (aged 2-4 years) rhesus macaques (Macaca mulatta) were observed at the California National Primate Research Center. Frequencies of mimicry defined a priori (e.g. following, postural mimicry) were observed over a course of 12 weeks. In separate observations during the same period, focal social behavior (e.g. aggression, play, affiliation) with group members was also observed. Subjects that exhibited higher degrees of mimicry were not more prosocial, but they received significantly more play overtures from social partners (p < 0.01). Additionally, rates of mimicry were higher in 2- and 3-year-olds than 4-year-olds. These results provide proof of principle in a small sample of monkeys that mimicry is associated with social advantages in a complex, semi-naturalistic setting in primates.

Broadening primate genomics: new insights into the ecology and evolution of primate gene regulation

Comparative analyses have played a key role in understanding how gene regulatory evolution contributes to primate phenotypic diversity. Recently, these studies have expanded to include a wider range of species, within-population as well as interspecific analyses, and research on wild as well as captive individuals. This expansion provides context for understanding genetic and environmental effects on gene regulation in humans, including the importance of the pathogen and social environments. Although taxonomic representation remains biased, inclusion of more species has also begun to reveal the evolutionary processes that explain whether and when gene regulation is conserved. Together, this work highlights how studies in other primates contribute to understanding evolution in our own lineage, and we conclude by identifying promising avenues for future work.

Development of an automated micropipette coating method for drug-coated balloons

Drug-coated balloons (DCBs) are a recent technology developed to treat peripheral artery disease (PAD). Along with a suitable formulation of antiproliferative drug and excipient, coating method is an important aspect of a DCB as these factors affect coating characteristics and drug delivery to the treatment site. The multiple release tailored medical devices DCB (MR-TMD-DCB), designed to achieve multiple inflations to treat complex PAD, contains paclitaxel (PAT) as the antiproliferative drug and polyethylene oxide (PEO) as the excipient. In our previous studies, the MR-TMD-DCB was coated using a manual dip coating method. In this study, an automated micropipette coating method was developed using a modified spray coating instrument to coat the MR-TMD-DCB. First, the coating formulation and strategy was optimized. A drug formulation of 16 wt% PAT and 4% wt/vol PEO, a polymer formulation of 2.5% wt/vol PEO, and a total of two drug layers produced a mostly uniform and thin coating with no defects and acceptable drug load. The balloon also had optimal drug uptake in arterial tissue in an in vitro flow model. Next, the reproducibility of the coating strategy was improved by optimizing the instrument parameters. The optimized instrument parameters (translational speed = 0.150 in/s, revolution rate = 100 rpm, flow rate = 0.6 ml/min) resulted in improved reproducibility of the drug load and similar coating properties as the DCB. This study demonstrated the ability to automate the micropipette process to obtain a balloon with optimal coating properties and drug tissue uptake.

DIMINISHED COMPLEXITY OF RELIGIOUS BELIEF AMONG DROPOUTS FROM A LONGITUDINAL STUDY OF COPING

Selective attrition is a common problem in longitudinal studies of older adults. Dropout is due to many factors, but frequently health concerns figure prominently as a reason for attrition. In light of previous work that suggests health problems reduce complexity of religious and other social involvements, the current study examines complexity of religiousness among dropouts and continuers in a longitudinal study of religion and health in later life. A random sample of 287 older adults living in Worcester, MA was assessed at two times of measurement 12 months apart using interview-based measures of religious orientation (Batson, Schoenrade, and Ventis, 1993) and health (OARS). Of the 287 who began the study, 72 dropped out and were not available to be assessed at 12 month assessment. Using Mplus, a three-factor model of Ends, Means, and Quest orientations demonstrated a good fit to the data in both dropout and continuer subsamples (e.g., CFI’s equaled .959 and .966, respectively). Diminished correlations between Ends, Means, and Quest orientations in the dropout vs. continuer subsample suggests diminished complexity of religious orientation among dropouts. Dropouts were more seriously ill, had higher levels of functional impairment, and demonstrated lower SES, suggesting increased vulnerability and fewer resources may have been the reason for dropping from the study as well as one possible cause of their diminished religious complexity.

Thatcher wheat line RL6149 carries Lr64 and a second leaf rust resistance gene on chromosome 1DS

The leaf rust resistance gene Lr64 in the Thatcher wheat RL6149 was mapped to chromosome 6AL with SNP and KASP markers and a second leaf rust resistance gene was mapped to chromosome 1DS. RL6149, a near-isogenic line of Thatcher wheat, carries leaf rust resistance gene Lr64 on chromosome arm 6AL. The objective of this study was to develop molecular markers that can be easily used to select wheat lines with Lr64. RL6149 was crossed with Thatcher and F₂ plants derived from a single F₁ plant were advanced to F₆ lines by single seed descent. The 100 F₇ recombinant inbred lines (RIL) were inoculated with two races of P.triticina that differed widely for virulence in order to identify resistant and susceptible RIL. Thirty RIL that differed for resistance and the parental lines were genotyped with the 90 K Infinium iSelect single nucleotide polymorphism (SNP) array to find closely linked markers with Lr64. Seven linked SNPs on chromosome arm 6AL were converted into Kompetitive Allele Specific PCR (KASP) markers that were genotyped on the 100 RIL. A genetic linkage map for the seven KASP markers spanned 19.1 cM on chromosome arm 6AL. KASP marker K-IWB59855 was tightly linked to Lr64. A second unexpected gene for leaf rust resistance also segregated in the F₇ lines. Four KASP markers that spanned 18.6 cM located the gene on chromosome 1DS. The KASP marker K-IWB38437 was tightly linked to the second leaf rust resistance gene.

Development of drug-coated balloon for the treatment of multiple peripheral artery segments

OBJECTIVE

Peripheral artery disease is the second most common cardiovascular disease. It can often occur in complex form when there is a presence of long, diffuse, and multiple lesions. Current treatments use either single long drug-coated balloons (DCBs) or multiple DCBs; however, treatment success is limited. The purpose of this study was to investigate the preclinical feasibility of our multiple-release Tailored Medical Devices DCB (MR-TMD-DCB) to treat multiple arterial segments using a single DCB.

METHODS

The MR-TMD-DCBs were developed using a two-layer coating approach. The DCBs were developed in a certified Current Good Manufacturing Practices facility using presterilized materials and reagent and then characterized for coating morphology, thermal and chemical changes, and in vitro particulate shedding. The drug loss, tissue uptake, and undelivered drug amounts were analyzed using an in vitro peripheral artery flow model and explanted pig arteries. Then, an in vivo survival study was performed using a healthy porcine model to measure the short-term drug uptake (seven swine; 14 treatments at day 1) and retention (seven swine; 14 treatments at day 7) in two different arterial segments after treatment with a single MR-TMD-DCB.

RESULTS

The coating on the MR-TMD-DCB was smooth and homogeneous with paclitaxel molecularly dispersed in its amorphous state. A negligible number of particulates were shed from the MR-TMD-DCB coating. A similar amount of drug was accurately delivered into two separate explanted arteries using a single MR-TMD-DCB during the in vitro flow model testing (707 ± 109 ng/mg in the first explanted artery and 783 ± 306 ng/mg in the second explanted artery). The MR-TMD-DCB treatment resulted in equivalent drug amounts in the two arterial segments at day 1 (63 ± 19 ng/mg in the first treatment site and 59 ±19 ng/mg in the second treatment site) and at day 7 (9 ± 6 ng/mg in the first treatment site and 10 ± 6 ng/mg in the second treatment site). In addition, the drug levels at each time point were in the clinically relevant range to prevent neointimal hyperplasia.

CONCLUSIONS

The MR-TMD-DCBs provided equivalent and clinically relevant drug retention levels into two different arterial segments. Thus, MR-TMD-DCBs can be used to accurately deliver drug into multiple arterial segments with the use of a single DCB. The clinical outcomes of these findings need further investigation. Future long-term pharmacokinetics and safety studies will be performed to evaluate the safety and efficacy of the MR-TMD-DCB.

Views from the clinic: Healthcare provider perspectives on whole genome sequencing in paediatrics

Whole genome sequencing (WGS) is a transformative technology which promises improved diagnostic rates compared to conventional genetic testing strategies and tailored approaches to patient care. Due to the practical and ethical complexities associated with using WGS, particularly in the paediatric context, input from a broad spectrum of healthcare providers can guide implementation strategies. We recruited healthcare providers from the largest paediatric academic health science centre in Canada and conducted semi-structured qualitative interviews, exploring experiences with and perceptions of the opportunities and challenges associated with WGS. Interview transcripts were coded and analyzed thematically. Interviews were completed with 14 genetics professionals (geneticists and genetic counsellors) and 15 non-genetics professionals (physician sub-specialists and nurses). Genetics professionals ordered genetic tests more often and reported greater confidence on pre- and post-test genetic counselling compared to non-genetics professionals. Most healthcare providers endorsed WGS when a more specific test was either not available or not likely to yield a diagnosis. While genetics professionals raised concerns regarding the time demands associated with reviewing WGS variants, non-genetics professionals reflected concerns about knowledge and training. Providers' position on reporting secondary variants to parents drew upon but was not limited to the concept of best interests. Taken together, understanding practical and principled matters of WGS from healthcare providers' perspectives can guide ongoing efforts to implement WGS in paediatrics.

Determining the cross-talk between smooth muscle cells and macrophages on a cobalt-chromium stent material surface using an in vitro postimplantation coculture model

Smooth muscle cells (SMCs) and macrophages are important cellular components involved in the development of complications following the implantation of cardiovascular devices. This leads to various disorders such as restenosis, chronic inflammation, and may ultimately result in device failure. In this study, we developed a postimplant stent coculture model using different ratios of SMCs and macrophages seeded on to cobalt-chromium alloy. The macrophages had an increased affinity to the coculture surfaces, which resulted in decreased SMC attachment to the alloy surfaces at the initial time point. Once adhered, the macrophages spread freely and displayed advanced stages of inflammation at 48 h when cocultured with SMCs. This resulted in an increased secretion of proinflammatory cytokines (tumor necrosis factor alpha, monocyte chemotactic protein 1, interleukin [IL]-6, and IL-8) by 48 h in the coculture samples with the greatest increase observed with the high number of macrophages. Therefore, the increased levels of proinflammatory cytokines promoted the growth of SMCs in coculture to a greater extent than when the SMCs were culture alone. Thus, this study demonstrated the constant cross-talk between SMCs and macrophages occurring on the postimplant stent surface. Similar coculture models can be used to test the biocompatibility of drugs and biomaterials at possible postimplantation scenarios. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 673-685, 2018.

In vitro particulate and in vivo drug retention study of a novel polyethylene oxide formulation for drug-coated balloons

OBJECTIVE

The purpose of this study was to investigate the newly developed drug-coated balloon (DCB) using polyethylene oxide (PEO) as a platform and to compare it directly with a commercially available DCB in a preclinical experimental setting.

METHODS

The PEO balloon was characterized for coating morphology and degree of paclitaxel (PAT) crystallinity. PAT tissue levels were then measured up to 30 days in a healthy porcine model (10 swine, 20 vessels) after treatment with either a PEO balloon or a commercially available DCB. An in vitro bench-top model was used to compare the particulates released from the PEO balloon and commercially available DCB.

RESULTS

The coating on the PEO balloon was smooth and homogeneous with PAT in its amorphous state. From the porcine survival study, the PAT tissue levels were comparable between PEO balloon and commercially available DCB after 7 days of treatment. Both the PEO balloon and the commercially available DCB retained therapeutic drug up to 30 days. During the simulated in vitro model, the PEO balloon shed significantly fewer particulates that were smaller than those of the commercially available DCB. Most important, the PEO balloon shed 25 times fewer large particulates than the commercially available DCB.

CONCLUSIONS

The amorphous PAT in the PEO balloon provided comparable drug tissue retention levels to those of the commercially available DCB and fewer particulates. Thus prepared PEO balloon proved to be safe and effective in the preclinical experimental setting. The clinical outcomes of these findings need further investigation.

Parents perspectives on whole genome sequencing for their children: qualified enthusiasm?

OBJECTIVE

To better understand the consequences of returning whole genome sequencing (WGS) results in paediatrics and facilitate its evidence-based clinical implementation, we studied parents' experiences with WGS and their preferences for the return of adult-onset secondary variants (SVs)-medically actionable genomic variants unrelated to their child's current medical condition that predict adult-onset disease.

METHODS

We conducted qualitative interviews with parents whose children were undergoing WGS as part of the SickKids Genome Clinic, a research project that studies the impact of clinical WGS on patients, families, and the healthcare system. Interviews probed parents' experience with and motivation for WGS as well as their preferences related to SVs. Interviews were analysed thematically.

RESULTS

Of 83 invited, 23 parents from 18 families participated. These parents supported WGS as a diagnostic test, perceiving clear intrinsic and instrumental value. However, many parents were ambivalent about receiving SVs, conveying a sense of self-imposed obligation to take on the 'weight' of knowing their child's SVs, however unpleasant. Some parents chose to learn about adult-onset SVs for their child but not for themselves.

CONCLUSIONS

Despite general enthusiasm for WGS as a diagnostic test, many parents felt a duty to learn adult-onset SVs. Analogous to 'inflicted insight', we call this phenomenon 'inflicted ought'. Importantly, not all parents of children undergoing WGS view the best interests of their child in relational terms, thereby challenging an underlying justification for current ACMG guidelines for reporting incidental secondary findings from whole exome and WGS.

Prediction of histological stage based on cystoscopic appearances of newly diagnosed bladder tumours

INTRODUCTION In the 75-80% of urothelial bladder cancers (UBC) presenting as non-muscle invasive bladder cancer (NMIBC), transurethral resection of bladder tumour (TURBT) is the key treatment and staging procedure. In the 20-25% of patients with muscle invasive bladder cancer (MIBC), further cross-sectional imaging is required to complete the staging process before considering radical treatment. Given the adverse effects of ionising radiation, clinicians identify patients believed to have MIBC, and so requiring further imaging pre-TURBT, at the tumour histology/stage based on the tumour's visual characteristics. There is minimal evidence describing the accuracy of such predictions in newly-diagnosed patients. METHODS Over a 6-year period, a database of patients undergoing resection of newly-diagnosed bladder lesions in a single UK centre was prospectively established. Predictions based on histology were simultaneously recorded, and the accuracy of these predictions of histology/stage subsequently assessed. RESULTS One hundred and twenty two (73.1%) patients with histologically confirmed NMIBC had predictions recorded versus 45 (26.9%) patients with MIBC. Visual assessment predictions of MIBC had a sensitivity of 88.9% (95% confidence interval [CI] 76.5%-95.2%) and a specificity of 91.0% (95% CI 84.6%-94.9%), giving a positive predictive value of 78.4% (95% CI 65.4%-87.5%) and a negative predictive value of 95.7% (95% CI 90.3%-98.1%). CONCLUSIONS We find that visual assessment is accurate in predicting the presence of MIBC. This supports the practice of stratifying patients at the time of initial cystoscopy for those requiring further radiological staging pre-TURBT.

Macrophage responses to 316L stainless steel and cobalt chromium alloys with different surface topographies

The surface topography of a biomaterial plays a vital role in determining macrophage interactions and influencing immune response. In this study, we investigated the effect of smooth and microrough topographies of commonly used metallic biomaterials such as 316 L stainless steel (SS) and cobalt-chromium (CoCr) alloys on macrophage interactions. The macrophage adhesion was greater on CoCr compared to SS, irrespective of their topographies. The macrophage activation and the secretion of most pro-inflammatory cytokines (TNF-α, IL-6, and IP-10) were greater on microrough surfaces than on smooth surfaces by day-1. However, by day-2, the macrophage activation on smooth surfaces was also significantly increased up to the same level as observed on the microrough surfaces, with more amount of cytokines secreted. The secretion of anti-inflammatory cytokine (IL-10) was significantly increased from day-1 to day-2 on all the alloy surfaces with the effect most prominently observed on microrough surfaces. The production of nitric oxide by the macrophages did not show any major substrate-dependent effect. The foreign body giant cells formed by macrophages were least observed on the microrough surfaces of CoCr. Thus, this study demonstrated that the nature of material (SS or CoCr) and their surface topographies (smooth or microrough) strongly influence the macrophage responses. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2658-2672, 2016.

Non-Pharmacological Factors in Drug Therapy—The Inter-Action of Doctor, Patient and Tablet Appearance in the Treatment of Anxiety/Depressive Syndromes

The degree to which placebo response is involved in an active treatment situation in normal clinical practice, and the factors comprising the placebo response, have been analyzed in a study on patients with anxiety/depressive syndromes. Four tablet preparations of different appearance but identical pharmacological activity were used over a three week period, and a comparison of therapeutic benefits between ‘treatments', doctors, and doctor—patient groupings was made, in addition to an analysis of the relationship of patients' self-assessments with their physicians' ratings.

The results showed that although direct pharmacological effect was paramount in determining therapeutic outcome, detailed differences were related to various placebo factors. The similarity between physicians' and patients' ratings tends to decrease during the course of treatment, and possible reasons for this are reviewed in the light of previous work.

Responses of endothelial cells, smooth muscle cells, and platelets dependent on the surface topography of polytetrafluoroethylene

In this study, the effect of different structures (flat, expanded, and electrospun) of polytetrafluoroethylene (PTFE) on the interactions of endothelial cells (ECs), smooth muscle cells (SMCs), and platelets was investigated. In addition, the mechanisms that govern the interactions between ECs, SMCs, and platelets with different structures of PTFE were discussed. The surface characterizations showed that the different structures of PTFE have the same surface chemistry, similar surface wettability and zeta potential, but uniquely different surface topography. The viability, proliferation, morphology, and phenotype of ECs and SMCs interacted with different structures of PTFE were investigated. Expanded PTFE (ePTFE) provided a relatively better surface for the growth of ECs. In case of SMC interactions, although all the different structures of PTFE inhibited SMC growth, a maximum inhibitory effect was observed for ePTFE. In case of platelet interactions, the electrospun PTFE provided a better surface for preventing the adhesion and activation of platelets. Thus, this study demonstrated that the responses of ECs, SMCs, and platelets strongly dependent on the surface topography of the PTFE. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2291-2304, 2016.

Preparation, characterization, in vitro drug release, and cellular interactions of tailored paclitaxel releasing polyethylene oxide films for drug-coated balloons

Drug-coated balloons (DCBs) are used to treat various cardiovascular diseases. Currently available DCBs carry drug on the balloon surface either solely or using different carriers. Several studies have shown that a significant amount of drug is lost in the blood stream during balloon tracking to deliver only a sub-therapeutic level of drug at the treatment site. This research is focused on developing paclitaxel (PAT) loaded polyethylene oxide (PEO) films (PAT-PEO) as a controlled drug delivery carrier for DCBs. An array of PAT-PEO films were developed in this study to provide tailored release of >90% of drug only at specific time intervals, which is the time frame required for carrying out balloon-based therapy. The characterizations of PAT-PEO films using SEM, FTIR, and DSC showed that the films developed were homogenous and the PAT was molecularly dispersed in the PEO matrix. Mechanical tests showed that most PAT-PEO films developed were flexible and ductile, with yield and tensile strengths not affected after PAT incorporation. The viability, proliferation, morphology, and phenotype of smooth muscle cells (SMCs) interacted with control-PEO and PAT-PEO films were investigated. All control-PEO and PAT-PEO films showed a significant inhibitory effect on the growth of SMCs, with the degree of inhibition strongly dependent on the w/v% of the polymer used. The PAT-PEO coating was produced on the balloons. The integrity of PAT-PEO coating was well maintained without any mechanical defects occurring during balloon inflation or deflation. The drug release studies showed that only 15% of the total PAT loaded was released from the balloons within the initial 1min (typical balloon tracking time), whereas 80% of the PAT was released between 1min and 4min (typical balloon treatment time). Thus, this study demonstrated the use of PEO as an alternate drug delivery system for the balloons.

STATEMENT OF SIGNIFICANCE

Atherosclerosis is primarily responsible for cardiovascular diseases (CVDs) in millions of patients every year. Drug-coated balloons (DCBs) are commonly used to treat various CVDs. However, in several currently used DCBs, a significant amount of drug is lost in the blood stream during balloon tracking to deliver only a sub-therapeutic level of drug at the treatment site. In this study, paclitaxel containing polyethylene oxide (PEO) films were developed to provide unique advantages including drug release profiles specifically tailored for balloon-based therapy, homogeneous films with molecularly dispersed drug, flexible and ductile films, and exhibits significant inhibitory effect on smooth muscle cell growth. Thus, this study demonstrated the use of PEO as an alternate drug delivery platform for DCBs to improve its efficacy.

Association mapping of North American spring wheat breeding germplasm reveals loci conferring resistance to Ug99 and other African stem rust races

BACKGROUND

The recently identified Puccinia graminis f. sp. tritici (Pgt) race TTKSK (Ug99) poses a severe threat to global wheat production because of its broad virulence on several widely deployed resistance genes. Additional virulences have been detected in the Ug99 group of races, and the spread of this race group has been documented across wheat growing regions in Africa, the Middle East (Yemen), and West Asia (Iran). Other broadly virulent Pgt races, such as TRTTF and TKTTF, present further difficulties in maintaining abundant genetic resistance for their effective use in wheat breeding against this destructive fungal disease of wheat. In an effort to identify loci conferring resistance to these races, a genome-wide association study was carried out on a panel of 250 spring wheat breeding lines from the International Maize and Wheat Improvement Center (CIMMYT), six wheat breeding programs in the United States and three wheat breeding programs in Canada.

RESULTS

The lines included in this study were grouped into two major clusters, based on the results of principal component analysis using 23,976 SNP markers. Upon screening for adult plant resistance (APR) to Ug99 during 2013 and 2014 in artificial stem rust screening nurseries at Njoro, Kenya and at Debre Zeit, Ethiopia, several wheat lines were found to exhibit APR. The lines were also screened for resistance at the seedling stage against races TTKSK, TRTTF, and TKTTF at USDA-ARS Cereal Disease Laboratory in St. Paul, Minnesota; and only 9 of the 250 lines displayed seedling resistance to all the races. Using a mixed linear model, 27 SNP markers associated with APR against Ug99 were detected, including markers linked with the known APR gene Sr2. Using the same model, 23, 86, and 111 SNP markers associated with seedling resistance against races TTKSK, TRTTF, and TKTTF were identified, respectively. These included markers linked to the genes Sr8a and Sr11 providing seedling resistance to races TRTTF and TKTTF, respectively. We also identified putatively novel Sr resistance genes on chromosomes 3B, 4D, 5A, 5B, 6A, 7A, and 7B.

CONCLUSION

Our results demonstrate that the North American wheat breeding lines have several resistance loci that provide APR and seedling resistance to highly virulent Pgt races. Using the resistant lines and the SNP markers identified in this study, marker-assisted resistance breeding can assist in development of varieties with elevated levels of resistance to virulent stem rust races including TTKSK.

Infection and Colonization of Several Bermudagrasses by Ophiosphaerella korrae

Bermudagrass (Cynodon spp.) is the most commonly used turfgrass in the southern United States where it is severely affected by spring dead spot (SDS) caused by Ophiosphaerella herpotricha, O. korrae, and O. narmari. In this study, infection of bermudagrass roots and stolons by O. korrae was characterized using a transformant that expressed the red fluorescent protein tdTomato. Roots of interspecific hybrid cultivars Midlawn and Tifway 419, C. transvaalensis accessions Uganda and 3200, and C. dactylon cultivar U3 were inoculated and observed from 2 to 14 days postinoculation (DPI) while stolons were observed from 2 to 22 DPI. For all five cultivars tested, a similar level of root colonization was observed; however, differences were observed in the rate of necrosis development. Necrosis of Tifway 419 and Midlawn tissues was evident at 2 DPI, in Uganda and 3200 at 8 DPI, and in U3 necrosis was often absent as late as 14 DPI. The fungus rapidly penetrated the root epidermis and colonized the cortex of all cultivars by 4 DPI. Colonization of stele tissues by O. korrae was rare in hybrid cultivars but common in C. transvaalensis and C. dactylon accessions. On intact stolons, the fungus did not penetrate the epidermis 22 DPI though epidermal necrosis was evident on the surface of only the hybrid bermudagrasses. Wounded stolons became necrotic in all cultivars. Infection and colonization of various bermudagrasses by O. korrae was found to be similar to that by O. herpotricha, suggesting that host genetic resistance may be used for effective management of SDS caused by both species.

Predictive genetic testing for adult-onset disorders in minors: a critical analysis of the arguments for and against the 2013 ACMG guidelines

The publication of the ACMG recommendations has reignited the debate over predictive testing for adult-onset disorders in minors. Response has been polarized. With this in mind, we review and critically analyze this debate. First, we identify long-standing inconsistencies between consensus guidelines and clinical practice regarding risk assessment for adult-onset genetic disorders in children using family history and molecular analysis. Second, we discuss the disparate assumptions regarding the nature of whole genome and exome sequencing underlying arguments of both supporters and critics, and the role these assumptions play in the arguments for and against reporting. Third, we suggest that implicit differences regarding the definition of best interests of the child underlie disparate conclusions as to the best interests of children in this context. We conclude by calling for clarity and consensus concerning the central foci of this debate.

Fluoroscopic sentinel events in neuroendovascular procedures: how to screen, prevent, and address occurrence

Radiation-induced skin injury during fluoroscopic procedures has been recently addressed by The Joint Commission, which defined prolonged fluoroscopy resulting in a cumulative peak skin dose of ≥15 Gy to a single field as a sentinel event (FSE). Neuroendovascular procedures can be associated with a high radiation skin dose and present risks such as potential FSEs. Managing these risks is the responsibility of the interventional neuroradiologist. In this review, we discuss hospital policies needed for screening and preventing FSEs, methods for minimizing radiation-induced skin injury, and actions necessary to address potential FSEs once they have occurred.

Interspecific nuclear-cytoplasmic compatibility controlled by genes on group 1 chromosomes in durum wheat

Triticum longissimum cytoplasm is incompatible with the T. turgidum nuclear genome. Two nuclear genes, scs and Vi, derived from the nuclear genome of T. timopheevii and by a spontaneous mutation, respectively, restore nuclear-cytoplasmic compatibility, normal plant vigor, and male fertility in these alloplasmic genotypes. The objectives of this study were (i) to determine the chromosomal locations of scs and Vi; (ii) to identify DNA markers for scs and Vi; and (iii) to determine the interactions involving the dosage of scs and Vi. Two populations segregating for scs and Vi were produced and scored for seedling vigor (indicating presence of scs) and degree of self-fertility (indicating presence of Vi). Four RFLP markers were mapped near scs. Aneuploid analysis revealed that these markers, and hence the scs gene, are located on the long arm of chromosome 1A. Four RFLP markers were mapped near Vi on 1BS. Results indicated that other factors may be inhibiting the expression of Vi. We determined the dosage of scs and Vi in both populations with the aid of the linked RFLP markers. Individuals with two versus one dose of scs had reduced self-fertility, while individuals with two versus one dose of Vi had similar self-fertility.

SU-E-I-10: Putting Teeth into Your CT Dosimetry Program: Approaches to Cone- Beam Dental/Maxillofacial CT Dosimetry

PURPOSE

To review and compare different approaches to the problem of dosimetry for limited field-of-view (FOV) cone beam CT devices for dental and maxillofacial applications.

METHODS

The determination of patient doses from specialized, cone-beam CT devices for dental and maxillofacial work requires medical physicists to re-evaluate their dosimetry methods. These devices work in cone-beam geometry, with an axial field dimension on the order of the lengths of the standard head CTDI phantom and pencil ionization chamber. They may also utilize less than 360 degree scans, resulting in asymmetrical radiation distributions. This operating regime is far from that for which conventional CT dosimetry was designed, and alternative approaches must be considered. The alternatives include extensions of conventional CT dosimetry currently used for large axial FOV scanners (e.g. the extended CTDI parameter (CTDIe) for the Toshiba Aquillion One with 160 mm axial FOV) and the new method based on point dosimetry measurements recently formalized in AAPM Report TG-111. Conventional, modified-conventional, and TG-111 dosimetry measurements are used in two CT dose phantoms (adult head and pediatric head) to obtain dose indices for the Planmeca ProMax 3D Max dental CT scanner. Surface dose maps are generated using radiochromic film for correlation with the chamber dosimetry.

RESULTS

Results for the three dosimetry approaches are compared for the specific case of the ProMax 3D Max scanner. Strengths and weaknesses of the three measurement paradigms for this type of application are compared.

CONCLUSIONS

The increasing availability of specialized scanners operating in full cone-beam mode will require the clinical medical physicist to be conversant with extensions to the CT dose index methodology suitable for this equipment.

First Detection in North America of Virulence in Wheat Leaf Rust (Puccinia triticina) to Seedling Plants of Wheat with Lr21

Leaf rust resistance gene Lr21 is present in hard red spring wheat (Triticum aestivum) cultivars grown in Minnesota, North Dakota, South Dakota, Manitoba, and Saskatchewan. Isolates of Puccinia triticina, the causal organism of wheat leaf rust, with virulence to this gene have not been previously detected in annual virulence surveys in the United States. (2). In 2010, hard red spring wheat cvs. Faller, RB07 (1), and Glenn, all with Lr21, had 0 to 5% levels of leaf rust severity, which was higher than in previous years in research plots in North Dakota and Minnesota. Leaf rust collections from wheat cultivars and germplasm lines with Lr21 at three locations in Minnesota and North Dakota were increased on plants of the leaf rust susceptible wheat Thatcher and the Thatcher line with Lr21. Single uredinia from the collections were isolated and increased on seedlings of Thatcher. The single uredinial isolates were inoculated to 7- to 8-day-old seedling plants of the set of 19 differential lines that are currently used in the leaf rust virulence surveys (2). Thatcher lines with Lr3bg, Lr14b, Lr20, and Lr23 were also tested. The isolates were also inoculated to seedling plants of hard red spring wheat cultivars with Lr21: Glenn, Steele-ND, Faller, RB07, Amidon, AC Cora, and McKenzie (3). Previous standardized methods for growing seedling plants, increase of rust isolates, inoculation, incubation, and evaluation of infection types (IT) were used (2). All tests with the Thatcher differential lines and the cultivars with Lr21 were repeated at least twice. Virulence phenotypes were described based on virulence to the 19 differentials in the P. triticina virulence nomenclature system used in the United States. (2). Two virulence phenotypes, TFBJQ and TFBGQ, with virulence to Lr21 were found at the three locations. TFBJQ is virulent (IT 3 to 4) to genes Lr1, 2a, 2c, 3, 10, 14a, 14b, 20, 21, 24, 26, 28, and avirulent (IT 0 to 2⁺) to genes Lr3ka, Lr3bg, Lr9, Lr11, Lr17, Lr18, Lr30, LrB, and Lr39/41. TFBGQ was avirulent to Lr14a and Lr20, but identical to TFBJQ for virulence and avirulence to the other resistance genes. Isolates of both phenotypes were virulent on seedlings of Faller, Glenn, RB07 (1), Steele-ND, AC Cora, and Amidon. McKenzie had IT of 2⁺ due to the additional presence of Lr16 (3). Both TFBJQ and TFBGQ have intermediate IT of 2⁺ to Lr16; IT 2⁺3 to Lr23, and are completely virulent to Lr1, Lr2a, and Lr10 that are present in hard red spring wheat cultivars. Both phenotypes have high IT to Lr24 and Lr26 that are present in soft red winter wheat and hard red winter wheat cultivars. The Lr21 virulent phenotypes likely arose by mutation from the group of P. triticina genotypes in the simple sequence repeat group NA-5 (4) that have intermediate IT of ;2^- to ;2⁺ to the Thatcher line with Lr21. P. triticina isolates with virulence to Lr21 are a new threat to wheat production since in 2010 more than 50% of the hard red spring wheat acreage in Minnesota and North Dakota relied on Lr21 for effective resistance to leaf rust. References: (1) J. A. Anderson et al. J. Plant Regist. 3:175, 2009. (2) J. A. Kolmer et al. Plant Dis. 94:775, 2010. (3) B. McCallum and P. Seto-Goh. Can. J. Plant Pathol. 32:387, 2010. (4) M. E. Ordoñez and J. A. Kolmer. Phytopathology 99:750, 2009.

Mapping QTL in the porcine MHC region affecting fatness and growth traits in a Meishan/Large White composite population

A number of studies have mapped QTL regulating porcine fatness and growth traits to the region of the major histocompatibility complex (MHC) on porcine chromosome 7 using various experimental crosses. The QTL results from crosses using the Chinese Meishan (MS) (slow growing and fat) are particularly interesting because the MS alleles have been found to be associated with increased growth rate and reduced backfat depth. We investigated these QTL further in a composite population derived previously over eight generations by intercrossing Meishan and the European Large White breeds. Genotype information from 32 markers in a 15cM target region was used in linkage and association analyses. A two-step variance component analysis identified QTL for three growth-related traits, explaining 19 ∼ 24% of the phenotypic variance with a confidence interval of 4 cM in the target region. SNP association analyses found that ss181128966 and ss181128924 within the QTL interval were strongly associated with the growth traits. Only weak signals for an effect on backfat depth were found in the association and linkage analyses, possibly because of past directional selection in the composite population.

Design of polymer nanocomposites in solution by polymer functionalization

Polymer nanocomposites, materials combining polymers and inorganic components such as nanosized crystallites or nanoparticles have attracted significant attention in recent years. A successful strategy for designing polymer nanocomposites is polymer functionalization via attaching functional groups with specific affinity for the inorganic component. In this paper, a systematic investigation by molecular dynamics of polymer functionalization for design of composites combining nanosize crystallites with multiblock polymers in solution is presented. It is shown that functionalization is an example of active self-assembly, where the resulting polymer nanocomposite exhibits a different type of order than the original pure polymer system (without inorganic components). Optimal polymer architectures and concentrations are identified appropriate for different applications, alongside an in-depth analysis on the origin and stability of the resulting phases as well as its experimental implications.

Pneumonia risk in COPD patients receiving inhaled corticosteroids alone or in combination: TORCH study results

Inhaled corticosteroids (ICS) are important in reducing exacerbation frequency associated with chronic obstructive pulmonary disease (COPD). However, little is known about the risk of associated infections. In a post hoc analysis of the TOwards a Revolution in COPD Health (TORCH) study, we analysed and identified potential risk factors for adverse event reports of pneumonia in this randomised, double-blind trial comparing twice-daily inhaled salmeterol (SAL) 50 microg, fluticasone propionate (FP) 500 microg, and the combination (SFC) with placebo in 6,184 patients with moderate-to-severe COPD over 3 yrs. Despite a higher withdrawal rate in the placebo arm, after adjusting for time on treatment, a greater rate of pneumonia was reported in the FP and SFC treatment arms (84 and 88 per 1,000 treatment-yrs, respectively) compared with SAL and placebo (52 and 52 per 1,000 treatment-yrs, respectively). Risk factors for pneumonia were age > or =55 yrs, forced expiratory volume in 1 s <50% predicted, COPD exacerbations in the year prior to the study, worse Medical Research Council dyspnoea scores and body mass index <25 kg.m(-2). No increase in pneumonia deaths with SFC was observed; this could not be concluded for FP. Despite the benefits of ICS-containing regimens in COPD management, healthcare providers should remain vigilant regarding the possible development of pneumonia as a complication in COPD patients receiving such therapies.

Adherence to inhaled therapy, mortality and hospital admission in COPD

BACKGROUND

Little is known about adherence to inhaled medication in chronic obstructive pulmonary disease (COPD) and the impact on mortality and morbidity.

METHODS

Data on drug adherence from a randomised double-blind trial comparing inhaled salmeterol 50 microg + fluticasone propionate 500 microg twice daily with placebo and each drug individually in 6112 patients with moderate to severe COPD over 3 years in the TORCH study were used. All-cause mortality and exacerbations leading to hospital admission were primary and secondary end points. The study of adherence was not specified a priori as an ancillary study.

RESULTS

Of the 4880 patients (79.8%) with good adherence defined as >80% use of study medication, 11.3% died compared with 26.4% of the 1232 patients (20.2%) with poor adherence. The annual rates of hospital admission for exacerbations were 0.15 and 0.27, respectively. The association between adherence and mortality remained unchanged and statistically significant after adjusting for other factors related to prognosis (hazard ratio 0.40 (95% CI 0.35 to 0.46), p<0.001). The association was even stronger when analysing on-treatment deaths only. Similarly, the association between adherence and hospital admission remained unchanged and significant in a multivariate analysis (rate ratio 0.58 (95% CI 0.44 to 0.73, p<0.001). The association between increased adherence and improved mortality and reduction in hospital admission was independent of study treatment. The effect of treatment was more pronounced in patients with good adherence than in those with poor adherence.

CONCLUSION

Adherence to inhaled medication is significantly associated with reduced risk of death and admission to hospital due to exacerbations in COPD. Further research is needed to understand these strong associations.

Mutations in LAMB2 causing a severe form of synaptic congenital myasthenic syndrome

Background:

We describe a severe form of congenital myasthenic syndrome (CMS) associated with congenital nephrosis and ocular malformations caused by two truncating mutations in the gene encoding the laminin β2 subunit (LAMB2).

Methods and results:

Mutational analysis in the affected patient, who has a history of a serious untoward reaction to treatment with acetylcholinesterase inhibition, revealed two frame-shifting heteroallelic mutations, a maternally inherited 1478delG and a paternally inherited 4804delC. An anconeus muscle biopsy demonstrated a profound distortion of the architecture and function of the neuromuscular junction, which was strikingly similar to that seen in mice lacking laminin β2 subunit. The findings included: pronounced reduction of the axon terminal size with encasement of the nerve endings by Schwann cells, severe widening of the primary synaptic cleft and invasion of the synaptic space by the processes of Schwann cells, and moderate simplification of postsynaptic folds and intact expression of the endplate acetylcholinesterase. The endplate potential quantal content was notably reduced, while the frequencies and amplitudes of miniature endplate potentials were only moderately diminished and the decay phases of miniature endplate potentials were normal. Western blot analysis of muscle and kidney tissue and immunohistochemistry of kidney tissue showed no laminin β2 expression.

Conclusion:

This case, which represents a new type of synaptic CMS, exemplifies the wide variability of phenotypes associated with LAMB2 mutations and underscores the fundamental role that laminin β2 plays in the development of the human neuromuscular junction.

Micellar crystals in solution from molecular dynamics simulations

Polymers with both soluble and insoluble blocks typically self-assemble into micelles, which are aggregates of a finite number of polymers where the soluble blocks shield the insoluble ones from contact with the solvent. Upon increasing concentration, these micelles often form gels that exhibit crystalline order in many systems. In this paper, we present a study of both the dynamics and the equilibrium properties of micellar crystals of triblock polymers using molecular dynamics simulations. Our results show that equilibration of single micelle degrees of freedom and crystal formation occur by polymer transfer between micelles, a process that is described by transition state theory. Near the disordered (or melting) transition, bcc lattices are favored for all triblocks studied. Lattices with fcc ordering are also found but only at lower kinetic temperatures and for triblocks with short hydrophilic blocks. Our results lead to a number of theoretical considerations and suggest a range of implications to experimental systems with a particular emphasis on Pluronic polymers.

Genetics of Leaf Rust Resistance in Brambling Wheat

The CIMMYT-developed spring wheat 'Brambling' has a high level of adult-plant resistance (APR) to leaf rust caused by Puccinia triticina. Our objectives were to determine the genetic basis of resistance in seedlings and adult plants and the magnitude of genotype × environment effects on the expression of APR. Brambling was crossed with spring wheat 'Jupateco 73S' that is highly susceptible to current predominant P. triticina races in Mexico and the United States. The F₁, F_2:3, F_4:5, F_4:6, and F_5:7 recombinant inbred lines (RILs) were evaluated under artificial field epidemics in Mexico and St. Paul, MN. The RILs also were tested with five races of P. triticina in greenhouse seedling experiments. A DNA marker was used to postulate the presence of slow-rusting gene Lr34 in the RILs. F₁ data suggested strong dominant effect of the APR genes in Brambling. The proportion of homozygous susceptible lines in each generation indicated the presence of three effective resistance genes in adult plants of Brambling in tests in Mexico and three or four genes in tests in St. Paul. The RILs segregated for seedling genes Lr14a and Lr23 and adult-plant slow-rusting gene Lr34 derived from Brambling and Lr17a from Jupateco 73S. Gene Lr23 conditioned APR to P. triticina races present in the St. Paul nursery and accounted for the additional effective gene at this location. Expression of APR was influenced by the environment in the RILs, even though Brambling displayed a consistent response, indicating that stability of APR can be achieved by combinations of slow-rusting resistance genes.

Reaction of Elite Wheat Genotypes from the Northern Great Plains of North America to Septoria Diseases

Stagonospora nodorum blotch (SNB), caused by Phaeosphaeria nodorum, and Septoria tritici blotch (STB), caused by Mycosphaerella graminicola, are the main pathogens of the Septoria disease complex of wheat (Triticum aestivum) in North America. This study was conducted to determine the disease reaction of 126 elite hard red spring, white, and durum wheat cultivars and advanced breeding lines collected from the northern Great Plains of the United States and Canada to SNB and STB. Seedlings of the 126 wheat genotypes were evaluated for resistance to SNB and STB under controlled environmental conditions. Moreover, these 126 wheat genotypes also were infiltrated with culture filtrate of P. nodorum isolate Sn2000. Based on disease reactions, three cultivars (McNeal, Dapps, and Oklee) and 12 advanced breeding lines (CA-901-580W, 97SO254-8-1, MN03291, MN03308, WA007925, MT0245, ND756, ND801, ND803, ND808, ND809, and ND811) adapted to the northern Great Plains were found to be resistant to both Septoria diseases and insensitive to the culture filtrate. Additionally, eight genetically diverse lines and cultivars, including two tetraploid wheat genotypes, were identified to be resistant to both Septoria diseases. These results suggest that the wheat genotypes contain a broad genetic base for resistance to the Septoria diseases in the northern Great Plains of the United States and Canada, and the resistant sources identified in this study may be utilized in wheat-breeding programs.

PTHrP increases transcriptional activity of the integrin subunit alpha5

Increasing evidence is emerging highlighting the role of parathyroid hormone-related protein (PTHrP) during metastasis by regulating cell adhesion. The current study demonstrated that modulation of PTHrP expression by PTHrP overexpression and small interfering RNA-induced silencing resulted in changes in cell adhesion and integrin expression. RNA interference of endogenous PTHrP caused a significant reduction in cell adhesion of a breast cancer cell line to collagen type I, fibronectin and laminin (P<0.05) and of a colon cancer cell to collagen type I and fibronectin (P<0.05). Overexpression of PTHrP induced a significant increase in cell adhesion of colon (P<0.0001) and breast (P<0.05) cancer cells to the same extracellular matrix proteins. These PTHrP-mediated effects were attributed to changes in integrin expression as the differences in adhesion profile correlated with the integrin expression profile. In an attempt to elucidate the mechanism whereby PTHrP regulates integrin expression, promoter activity of the integrin α₅ subunit was analysed and significant increases in transcriptional activity were observed in PTHrP overexpressing cells (P<0.0001), which was dependent on nuclear localisation. These results indicate that modulation of cell adhesion is a normal physiological action of PTHrP, mediated by increasing integrin gene transcription.