Mechanism of Bloom syndrome complex assembly required for double Holliday junction dissolution and genome stability

The RecQ-like helicase BLM cooperates with topoisomerase IIIα, RMI1, and RMI2 in a heterotetrameric complex (the "Bloom syndrome complex") for dissolution of double Holliday junctions, key intermediates in homologous recombination. Mutations in any component of the Bloom syndrome complex can cause genome instability and a highly cancer-prone disorder called Bloom syndrome. Some heterozygous carriers are also predisposed to breast cancer. To understand how the activities of BLM helicase and topoisomerase IIIα are coupled, we purified the active four-subunit complex. Chemical cross-linking and mass spectrometry revealed a unique architecture that links the helicase and topoisomerase domains. Using biochemical experiments, we demonstrated dimerization mediated by the N terminus of BLM with a 2:2:2:2 stoichiometry within the Bloom syndrome complex. We identified mutations that independently abrogate dimerization or association of BLM with RMI1, and we show that both are dysfunctional for dissolution using in vitro assays and cause genome instability and synthetic lethal interactions with GEN1/MUS81 in cells. Truncated BLM can also inhibit the activity of full-length BLM in mixed dimers, suggesting a putative mechanism of dominant-negative action in carriers of BLM truncation alleles. Our results identify critical molecular determinants of Bloom syndrome complex assembly required for double Holliday junction dissolution and maintenance of genome stability.

Coordinated β-globin expression and α2-globin reduction in a multiplex lentiviral gene therapy vector for β-thalassemia

A primary challenge in lentiviral gene therapy of β-hemoglobinopathies is to maintain low vector copy numbers to avoid genotoxicity while being reliably therapeutic for all genotypes. We designed a high-titer lentiviral vector, LVβ-shα2, that allows coordinated expression of the therapeutic β^A-T87Q-globin gene and of an intron-embedded miR-30-based short hairpin RNA (shRNA) selectively targeting the α2-globin mRNA. Our approach was guided by the knowledge that moderate reduction of α-globin chain synthesis ameliorates disease severity in β-thalassemia. We demonstrate that LVβ-shα2 reduces α2-globin mRNA expression in erythroid cells while keeping α1-globin mRNA levels unchanged and β^A-T87Q-globin gene expression identical to the parent vector. Compared with the first β^A-T87Q-globin lentiviral vector that has received conditional marketing authorization, BB305, LVβ-shα2 shows 1.7-fold greater potency to improve α/β ratios. It may thus result in greater therapeutic efficacy and reliability for the most severe types of β-thalassemia and provide an improved benefit/risk ratio regardless of the β-thalassemia genotype.

NEW DEVELOPMENTS AND APPLICATIONS OF SUPERHEATED EMULSIONS: WARHEAD VERIFICATION AND SPECIAL NUCLEAR MATERIAL INTERDICTION

In recent years, neutron detection with superheated emulsions has received renewed attention thanks to improved detector manufacturing and read-out techniques, and thanks to successful applications in warhead verification and special nuclear material (SNM) interdiction. Detectors are currently manufactured with methods allowing high uniformity of the drop sizes, which in turn allows the use of optical read-out techniques based on dynamic light scattering. Small detector cartridges arranged in 2D matrices are developed for the verification of a declared warhead without revealing its design. For this application, the enabling features of the emulsions are that bubbles formed at different times cannot be distinguished from each other, while the passive nature of the detectors avoids the susceptibility to electronic snooping and tampering. Large modules of emulsions are developed to detect the presence of shielded special nuclear materials hidden in cargo containers 'interrogated' with high energy X-rays. In this case, the enabling features of the emulsions are photon discrimination, a neutron detection threshold close to 3 MeV and a rate-insensitive read-out.

Novel findings from a beta coronavirus outbreak on an American Miniature Horse breeding farm in upstate New York

This case report describes an outbreak and novel findings associated with a beta coronavirus (BCoV) infection that occurred on an American Miniature Horse (AMH) breeding farm in upstate New York, in January and February of 2013. Twenty-nine AMH and one donkey were present on the farm when the outbreak occurred. One 10-year-old Quarter Horse mare, stabled at a separate location and owned by an employee of the farm, also tested positive. A polymerase chain reaction (PCR) assay for the detection of BCoV was performed at the Animal Health Diagnostic Center (AHDC) at Cornell on all faecal samples. The PCR assay used detects multiple beta coronaviruses, including, but not limited to, equine enteric coronavirus (ECoV). Novel findings regarding this BCoV infection in horses were recognised in this outbreak study. To the authors' knowledge, this is the largest outbreak of BCoV described thus far in a closed herd on a single premise. The case fatality rate was 0% unlike that described in a previous outbreak of ECoV involving miniature horses and a miniature donkey (Fielding et al. 2015). The morbidity rate was lower in this outbreak than in previously described studies (Oue et al. 2013; Pusterla et al. 2013). This outbreak also demonstrated the potential for BCoV transmission via farm personnel. The duration of shedding of virus in the faeces among some asymptomatic horses in this outbreak was longer than previously described clinical cases of ECoV (Pusterla et al. 2013; Nemoto et al. 2014). This study suggests that asymptomatic animals may play a role in the maintenance of BCoV during an outbreak; therefore, the need for diagnostic testing of both clinically affected and apparently clinically normal horses on a premises followed by appropriate biosecurity and control measures.

A qualitative metasynthesis exploring the impact of prostate cancer and its management on younger, unpartnered and gay men

Prostate cancer (PCa) can negatively impact on men's sexual, urinary and emotional functioning, affecting quality of life. Most men with PCa are older (≥65 years), married and heterosexual and little is known about the impact on men who are younger, unpartnered or gay. We aimed to synthesise existing qualitative research on these three groups of men. A systematic metasynthesis was undertaken that included data on the unique impacts of PCa on younger (<65 years) (n = 7 papers), unpartnered (n = 17 papers) or gay or bisexual men (n = 11 papers) using a modified meta-ethnographic approach. The three overarching constructs illustrated the magnified disruption to men's biographies, that included: marginalisation, isolation and stigma-relating to men's sense of being "out of sync"; the burden of emotional and embodied vulnerabilities and the assault on identity-illustrating the multiple threats to men's work, sexual and social identities; shifting into different communities of practice-such as the shift from being part of a sexually active community to celibacy. These findings suggest that PCa can have a particular impact on the quality of life of younger, unpartnered and gay men. This has implications for the provision of tailored support and information to these potentially marginalised groups.

Ocular Lesions in Red-Tailed Hawks (Buteo jamaicensis) With Naturally Acquired West Nile Disease

Ocular lesions are common in red-tailed hawks with West Nile (WN) disease. These lesions consist of pectenitis, choroidal or retinal inflammation, or retinal necrosis, but detailed investigation of the ocular lesions is lacking. Postmortem examination of the eyes of 16 red-tailed hawks with naturally acquired WN disease and 3 red-tailed hawks without WN disease was performed using histopathology, immunohistochemistry for West Nile virus (WNV) antigen, glial fibrillary acid protein, cleaved caspase-3, and the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method. Retinal lesions were classified as type I or type II lesions. Type I lesions were characterized by lymphoplasmacytic infiltrates in the subjacent choroid with degeneration limited to the outer retina (type Ia lesion) or with degeneration and necrosis of the outer retina or outer and inner retina (type Ib lesion) while retinal collapse, atrophy, and scarring were hallmarks of type II lesions. Type II retinal lesions were associated with a more pronounced choroiditis. Although not statistically significant, WNV antigen tended to be present in larger quantity in type Ib lesions. Type I lesions are considered acute while type II lesions are chronic. The development of retinal lesions was associated with the presence of an inflammatory infiltrate in the choroid. A breakdown of the blood-retina barrier is suspected to be the main route of infection of the retina. Within the retina, virus appeared to spread via both neuronal and Müller cell processes.

A Cas9 Variant for Efficient Generation of Indel-Free Knockin or Gene-Corrected Human Pluripotent Stem Cells

While Cas9 nucleases permit rapid and efficient generation of gene-edited cell lines, the CRISPR-Cas9 system can introduce undesirable “on-target” mutations within the second allele of successfully modified cells via non-homologous end joining (NHEJ). To address this, we fused the Streptococcus pyogenes Cas9 (SpCas9) nuclease to a peptide derived from the human Geminin protein (SpCas9-Gem) to facilitate its degradation during the G₁ phase of the cell cycle, when DNA repair by NHEJ predominates. We also use mRNA transfection to facilitate low and transient expression of modified and unmodified versions of Cas9. Although the frequency of homologous recombination was similar for SpCas9-Gem and SpCas9, we observed a marked reduction in the capacity for SpCas9-Gem to induce NHEJ-mediated indels at the target locus. Moreover, in contrast to native SpCas9, we demonstrate that transient SpCas9-Gem expression enables reliable generation of both knockin reporter cell lines and genetically repaired patient-specific induced pluripotent stem cell lines free of unwanted mutations at the targeted locus.

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“On-target” deleterious mutations are often encountered with CRISPR-Cas9 gene editing

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SpCas9-Gem retains gene-targeting efficiency with reduced NHEJ activity

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SpCas9-Gem facilitates derivation of “indel-free” gene-edited iPSCs

The therapeutic potential of genome editing for β-thalassemia

The rapid advances in the field of genome editing using targeted endonucleases have called considerable attention to the potential of this technology for human gene therapy. Targeted correction of disease-causing mutations could ensure lifelong, tissue-specific expression of the relevant gene, thereby alleviating or resolving a specific disease phenotype. In this review, we aim to explore the potential of this technology for the therapy of β-thalassemia. This blood disorder is caused by mutations in the gene encoding the β-globin chain of hemoglobin, leading to severe anemia in affected patients. Curative allogeneic bone marrow transplantation is available only to a small subset of patients, leaving the majority of patients dependent on regular blood transfusions and iron chelation therapy. The transfer of gene-corrected autologous hematopoietic stem cells could provide a therapeutic alternative, as recent results from gene therapy trials using a lentiviral gene addition approach have demonstrated. Genome editing has the potential to further advance this approach as it eliminates the need for semi-randomly integrating viral vectors and their associated risk of insertional mutagenesis. In the following pages we will highlight the advantages and risks of genome editing compared to standard therapy for β-thalassemia and elaborate on lessons learned from recent gene therapy trials.

Diffuse intrinsic pontine glioma treated with prolonged temozolomide and radiotherapy--results of a United Kingdom phase II trial (CNS 2007 04)

Diffuse intrinsic pontine glioma (DIPG) has a dismal prognosis with no chemotherapy regimen so far resulting in any significant improvement over standard radiotherapy. In this trial, a prolonged regimen (21/28d) of temozolomide was studied with the aim of overcoming O(6)-methylguanine methyltransferase (MGMT) mediated resistance. Forty-three patients with a defined clinico-radiological diagnosis of DIPG received radiotherapy and concomitant temozolomide (75 mg/m(2)) after which up to 12 courses of 21d of adjuvant temozolomide (75-100mg/m(2)) were given 4 weekly. The trial used a 2-stage design and passed interim analysis. At diagnosis median age was 8 years (2-20 years), 81% had cranial nerve abnormalities, 76% ataxia and 57% long tract signs. Median Karnofsky/Lansky score was 80 (10-100). Patients received a median of three courses of adjuvant temozolomide, five received all 12 courses and seven did not start adjuvant treatment. Three patients were withdrawn from study treatment due to haematological toxicity and 10 had a dose reduction. No other significant toxicity related to temozolomide was noted. Overall survival (OS) (95% confidence interval (CI)) was 56% (40%, 69%) at 9 months, 35% (21%, 49%) at 1 year and 17% (7%, 30%) at 2 years. Median survival was 9.5 months (range 7.5-11.4 months). There were five 2-year survivors with a median age of 13.6 years at diagnosis. This trial demonstrated no survival benefit of the addition of dose dense temozolomide, to standard radiotherapy in children with classical DIPG. However, a subgroup of adolescent DIPG patients did have a prolonged survival, which needs further exploration.

Assess, compare and enhance the status of Persons with Multiple Sclerosis (MS) in Europe: a European Register for MS

OBJECTIVES

Persons with multiple sclerosis (PwMS) experience health-related quality of life (HRQoL) problems greatly differing across Europe, and the European Union (EU) faces deep inequalities in MS management from country to country. Through the establishment of a European MS Register (EUReMS), an effective action is proposed to improve the overall knowledge on MS and support effective intervention programmes at EU and national political level. EUReMS aims to achieve consensus on its mission and vision, to define existing data providers, to develop models driving future MS health policies and research, to develop an information technology (IT) infrastructure for a data set, to develop a European shared governance and to secure providers' data provision into EUReMS.

MATERIALS AND METHODS

EUReMS is meant to build on a minimum set of core data from existing national and regional population-based MS registries and from PwMS' perspectives. EUReMS' main partner is the European MS Platform (EMSP) acting in collaboration with associated and collaborating European partners.

RESULTS

EUReMS was launched in July 2011. A Consensus Statement on purposes, vision, mission and strategies was produced in December 2011, and a comprehensive survey on existing MS data collections in Europe has been performed, and the EUReMS data mask is currently being discussed.

CONCLUSIONS

EUReMS will represent a tool to provide up to date, comparable and sustainable MS data through an effective and credible register, which will encourage extensive knowledge building of MS, more equitable policies and higher standards in MS treatment and services.

The impact of a managed transition of care upon psychosocial characteristics and patient satisfaction in a cohort of adult survivors of childhood cancer

OBJECTIVE

Many adult survivors of childhood cancer receive care in paediatric departments, despite national policy to transition their care to adult services. When long-term follow-up care for survivors of childhood cancer in our region moved from a paediatric to an adult environment in 2009, we prospectively assessed the impact of this change on patient satisfaction.

METHODS

Questionnaire data were collected in paediatric and adult clinical environments regarding the level of satisfaction with care and potential mediators: quality of life, psychological health and social difficulties. Predictors of satisfaction and optimum longitudinal risk-based care were described using path analysis and compared with previously described models.

RESULTS

There was no significant difference in satisfaction between the paediatric and adult settings. Short waiting times and increased understanding of the purpose of follow-up were significantly associated with increased satisfaction. Those with a higher perception of health problems and those that were older were more likely to not attend all of their clinic appointments.

CONCLUSIONS

Within our service, transition to adult care did not impact significantly upon patient satisfaction. Shorter waits and knowing why participants were attending the clinic increased satisfaction. Joint working between adult and paediatric cancer professionals enabled adult survivors of childhood cancer to receive highly satisfactory care in adult services.

Implementing improved post-treatment care for cancer survivors in England, with reflections from Australia, Canada and the USA

Increasing cancer incidence together with improved survival rates are contributing to the growing number of cancer survivors. Survivors may encounter a range of potential effects as a result of the cancer itself or cancer treatments. Traditionally, the major focus of follow-up care has been on detection of cancer recurrence; however, the efficacy of such strategies is questionable. Traditional follow-up frequently fails to identify or adequately address many survivors’ concerns. Aftercare needs to be planned to enable better outcomes for survivors, while using scarce health-care resources efficiently. This review focuses on provision of survivorship care, rather than on research. England’s National Cancer Survivorship Initiative has developed principles for improved care of those living with and beyond cancer. These include risk-stratified pathways of care, the use of treatment summaries and care plans, information and education to enable choice and the confidence to self manage, rapid re-access to specialist care, remote monitoring and well-coordinated care. Many of these principles are relevant internationally, though preferred models of care will depend on local circumstances.

SU-E-T-11: LINAC Dose Profiling Using Cherenkov Emission Imaging

PURPOSE

To demonstrate the potential for fast 3D dose profile imaging of a LINAC beam using images of the induced Cherenkov radiation in a water tank. A specialized time-gated imaging system was developed as a prototype to quantify and compare with Monte Carlo, to illustrate the concept.

METHODS

Images were acquired from a water tank during irradiation from a 6 MV Varian-2100C linear accelerator beam using a time-gated CCD-based imaging system. The camera was placed normal to the tank wall to minimize parallax reflections, and resultant images were produced by evaluating the median of each pixel in a stack of 2000 images taken at a rate of 60 Hz with an exposure time of 10 ms. Experimental data was compared to images obtained from GEANT4 simulations of the optical setup.

RESULTS

Examination of the scored quantities for dose and generated Cherenkov photons indicates that there is a strong similarity, which can be explained by considering the electron energy losses per unit path length. However, due to the complex convolution of the Cherenkov emission directionality and camera lens angular field of view, this relationship is distorted. These errors can be calibrated using the GEANT4 simulations to more accurately reflect the intrinsic dose in the water volume.

CONCLUSIONS

This work demonstrates dose profiling using the induced Cherenkov radiation signal for the first time. These preliminary results serve as a proof of concept of imaging at one azimuthal angle. Analogous to SPECT, the technique could easily be translated to multiple angles yielding full dose reconstructions following filtered back projection. Further refinement of this technology could be the first step in a paradigm shift towards an alternative method for fast radiation field analysis. Advantages would include increased speed, as well as the ability to profile dynamic beam shapes within transparent solid anthropomorphic phantoms. This work has been financially supported by NIH grant R01CA109558.

Survival trends of cancer amongst the south Asian and non-south Asian population under 30 years of age in Yorkshire, UK

INTRODUCTION

Several studies have shown differences in survival trends between ethnic groups across adults with cancer in the UK. It is unclear whether these differences exist exclusively in the older adult population or whether they begin to emerge in children and young adults.

METHODS

Subjects (n=3534) diagnosed with cancer under 30 years of age in Yorkshire between 1990 and 2005 were analysed. Differences in survival rates for diagnostic subgroups were estimated by ethnic group (south Asian or not) using Kaplan-Meier estimation and Cox regression.

RESULTS

When compared to non-south Asians (all other ethnic groups excluding south Asians) a significant increased risk of death was seen for south Asians with leukaemia (hazard ratio (HR)=1.75; 95% confidence interval (CI)=1.11-2.76) and lymphoma (HR=2.05; 95% CI=1.09-3.87), whereas south Asians with solid tumours other than central nervous system tumours had a significantly reduced risk of death(HR=0.50; 95% CI=0.28-0.89). This was independent of socioeconomic deprivation.

CONCLUSION

We found evidence of poorer survival outcomes for south Asians compared to non-south Asian children and young adults with leukaemia and lymphoma, but better outcomes for south Asian children and young adults with other solid tumours. This needs to be explained, and carefully addressed in the on-going development of cancer services.

A simple practical patient-reported clinic satisfaction measure for young adults

Background:

The development of practical patient-reported outcome measures (PROM) to assess the user view of health programmes is increasingly important. Valid, shorter instruments are more likely to be used and completed than extensive questionnaires.

Methods:

Consecutive adult outpatient attendees who were long-term survivors of childhood cancer completed the 16-item Patient Satisfaction with Communication Questionnaire (PSCQ). These data were used to develop a three-item questionnaire. The brief PROM was validated against data from a second, independent survey conducted in a similar fashion.

Results:

In all, 93 individuals contributed PSCQ data, a response rate of 63%. The brief PROM was highly correlated with the original PSCQ in derivation (ρ=0.87, P<0.001) and validation (ρ=0.82, P<0.001) data sets. Using a cutoff of scores <9 to indicate dissatisfaction showed fair discrimination in derivation (sensitivity 85%, specificity 80%) and validation data sets (sensitivity 75%, specificity 78%).

Conclusion:

It is possible to quickly and efficiently assess satisfaction with follow-up clinics with three questions. This brief PROM could prove useful in monitoring services quality by allowing clinic users to provide timely feedback on their care.

Cancer incidence among the south Asian and non-south Asian population under 30 years of age in Yorkshire, UK

Background:

Few studies have examined epidemiological differences between ethnic groups for children and young adults with cancer.

Methods:

Subjects aged 0–29 years, diagnosed between 1990 and 2005 in the former Yorkshire Regional Health Authority, were included in the analysis. Ethnicity (south Asian or not) was assigned using name analysis program and Hospital Episode Statistics data. Differences in incidence (per 1 000 000 person-years) rates and trends were analysed using joinpoint and Poisson regression analysis.

Results:

Overall cancer incidence was similar for south Asians (12.1, 95% CI: 10.7–13.5; n=275) and non-south Asians (12.6, 95% CI: 12.2–13.1; n=3259). Annual incidence rates increased significantly by 1.9% per year on average (95% CI: 1.2–2.6%), especially for south Asians (7.0% 95% CI: 4.2–9.9%).

Conclusion:

If present trends continue, the higher rate of increase seen among south Asians aged 0–29 years in Yorkshire will result in three times higher cancer incidence than non-south Asians by 2020.

Educational attainment among adult survivors of childhood cancer in Great Britain: a population-based cohort study

BACKGROUND

Previous studies of educational attainment among childhood cancer survivors were small, had contradictory findings, and were not population based. This study investigated educational attainment in a large population-based cohort of survivors of all types of childhood cancer in Great Britain.

METHODS

Four levels of educational attainment among 10,183 cancer survivors--degree, teaching qualification, advanced (A') levels, and ordinary (O') levels--were compared with expected levels in the general population. A questionnaire was used to obtain educational attainment data for survivors, and comparable information for the general population was available from the General Household Survey. Factors associated with level of educational attainment achieved by cancer survivors were identified using multivariable logistic regression together with likelihood ratio tests. Logistic regression adjusting for age and sex was used for comparisons with the general population. All statistical tests were two-sided.

RESULTS

Childhood cancer survivors had lower educational attainment than the general population (degree: odds ratio [OR] = 0.77, 99% confidence interval [CI] = 0.68 to 0.87; teaching qualification: OR = 0.85, 99% CI = 0.77 to 0.94; A'level: OR = 0.85, 99% CI = 0.78 to 0.93; O'level: OR = 0.81, 99% CI = 0.74 to 0.90; P < .001, all levels). Statistically significant deficits were restricted to central nervous system (CNS) neoplasm and leukemia survivors. For leukemia, only those treated with radiotherapy were considered. Odds ratios for achievement by irradiated CNS tumor survivors were 50%-74% of those for cranially irradiated leukemia or nonirradiated CNS tumor survivors. Survivors at greater risk of poorer educational outcomes included those treated with cranial irradiation, diagnosed with a CNS tumor, older at questionnaire completion, younger at diagnosis, diagnosed with epilepsy, and who were female.

CONCLUSIONS

Specific groups of childhood cancer survivors achieve lower-than-expected educational attainment. Detailed educational support and implementation of regular cognitive assessment may be indicated for some groups to maximize long-term function.

Fatal pneumonitis in children with metastatic rhabdomyosarcoma following whole lung radiotherapy and sequential epirubicin

Interstitial pneumonitis is a recognized complication following whole lung radiotherapy. We report two cases in which fatal pneumonitis appeared to be precipitated by the administration of epirubicin-containing combination chemotherapy within 7 weeks of completion of whole lung radiotherapy. These cases highlight a potentially fatal interaction between radiotherapy and modern chemotherapy regimens.