Dynamics of magnetization at infinite temperature in a Heisenberg spin chain

Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin dynamics of the one-dimensional Heisenberg model were conjectured as to belong to the Kardar-Parisi-Zhang (KPZ) universality class based on the scaling of the infinite-temperature spin-spin correlation function. In a chain of 46 superconducting qubits, we studied the probability distribution of the magnetization transferred across the chain's center, [Formula: see text]. The first two moments of [Formula: see text] show superdiffusive behavior, a hallmark of KPZ universality. However, the third and fourth moments ruled out the KPZ conjecture and allow for evaluating other theories. Our results highlight the importance of studying higher moments in determining dynamic universality classes and provide insights into universal behavior in quantum systems.

Stable quantum-correlated many-body states through engineered dissipation

Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.

Aging impairs the osteocytic regulation of collagen integrity and bone quality

Poor bone quality is a major factor in skeletal fragility in elderly individuals. The molecular mechanisms that establish and maintain bone quality, independent of bone mass, are unknown but are thought to be primarily determined by osteocytes. We hypothesize that the age-related decline in bone quality results from the suppression of osteocyte perilacunar/canalicular remodeling (PLR), which maintains bone material properties. We examined bones from young and aged mice with osteocyte-intrinsic repression of TGFβ signaling (TβRIIocy-/-) that suppresses PLR. The control aged bone displayed decreased TGFβ signaling and PLR, but aging did not worsen the existing PLR suppression in male TβRIIocy-/- bone. This relationship impacted the behavior of collagen material at the nanoscale and tissue scale in macromechanical tests. The effects of age on bone mass, density, and mineral material behavior were independent of osteocytic TGFβ. We determined that the decline in bone quality with age arises from the loss of osteocyte function and the loss of TGFβ-dependent maintenance of collagen integrity.

Identification of biomarker candidates for exfoliative glaucoma from autoimmunity profiling

BACKGROUND

Exfoliative glaucoma (XFG) is a subtype of open-angle glaucoma characterized by distinctive extracellular fibrils and a yet unknown pathogenesis potentially involving immune-related factors. The aim of this exploratory study was to identify biomarkers for XFG using data from autoimmunity profiling performed on blood samples from a Scandinavian cohort of patients.

METHODS

Autoantibody screening was analyzed against 258 different protein fragments in blood samples taken from 30 patients diagnosed with XFG and 30 healthy donors. The 258 protein fragments were selected based on a preliminary study performed on 3072 randomly selected antigens and antigens associated with the eye. The "limma" package was used to perform moderated t-tests on the proteomic data to identify differentially expressed reactivity between the groups.

RESULTS

Multiple associated genes were highlighted as possible biomarker candidates including FUT2, CDH5, and the LOX family genes. Using seven variables, our binary logistic regression model was able to classify the cases from the controls with an AUC of 0.85, and our reduced model using only one variable corresponding to the FUT2 gene provided an AUC of 0.75, based on LOOCV. Furthermore, over-representation gene analysis was performed to identify pathways that were associated with antigens differentially bound to self-antibodies. This highlighted the enrichment of pathways related to collagen fibril formation and the regulatory molecules mir-3176 and mir-876-5p.

CONCLUSIONS

This study suggests several potential biomarkers that may be useful in developing further models of the pathology of XFG. In particular, CDH5, FUT2, and the LOX family seem to have a relationship which merits additional exploration.

Measurement-induced entanglement and teleportation on a noisy quantum processor

Measurement has a special role in quantum theory1: by collapsing the wavefunction, it can enable phenomena such as teleportation2 and thereby alter the 'arrow of time' that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time3-10 that go beyond the established paradigms for characterizing phases, either in or out of equilibrium11-13. For present-day noisy intermediate-scale quantum (NISQ) processors14, the experimental realization of such physics can be problematic because of hardware limitations and the stochastic nature of quantum measurement. Here we address these experimental challenges and study measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping9,15-17 to avoid mid-circuit measurement and access different manifestations of the underlying phases, from entanglement scaling3,4 to measurement-induced teleportation18. We obtain finite-sized signatures of a phase transition with a decoding protocol that correlates the experimental measurement with classical simulation data. The phases display remarkably different sensitivity to noise, and we use this disparity to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realizing measurement-induced physics at scales that are at the limits of current NISQ processors.

Association between Regular Vaginal Dilation and/or Sexual Activity and Long-Term Vaginal Morbidity in Cervical Cancer Survivors

PURPOSE/OBJECTIVE(S)

To evaluate the association between regular vaginal dilation and/or sexual activity and vaginal morbidity in locally advanced cervical cancer patients after definitive radiochemotherapy and image-guided adaptive brachytherapy from the EMBRACE I study.

MATERIALS/METHODS

Physician-assessed vaginal morbidity (CTCAE v.3), vaginal dilation and patient-reported sexual activity (EORTC QLQ CX24) were assessed at baseline, every 3 months in the 1st year, every 6 months in the 2nd and 3rd year and yearly thereafter. For this longitudinal analysis, a subgroup of patients was selected with at least 3 follow-ups with information on vaginal dilation and/or sexual activity. Vaginal penetration summarized either the use of vaginal dilators or sexual activity or both. Regular vaginal penetration was defined if reported in ≥50%, infrequent if reported in <50% and absent if reported in 0% of follow-ups. Actuarial estimates of vaginal morbidity were calculated with Kaplan-Meier method and included the individual symptoms: vaginal dryness, stenosis, mucositis and bleeding. Group comparisons were evaluated with the log-rank test.

RESULTS

The EMBRACE I study included 1416 patients overall (2008-2015); the subgroup of patients for this longitudinal evaluation consists of 882 patients, with a median follow-up of 60 months (IQR 47-77). Of those, 565 (64%) reported regular, 205 (23%) infrequent and 112 (13%) no penetration. Reporting regular penetration was associated with a significantly lower risk of vaginal stenosis G≥2 of 23% at 5 years, compared to reporting of infrequent (37%) and no penetration (36%, p≤0.001). However, reporting regular penetration was associated with a significantly higher risk for vaginal dryness G≥1 (72% vs. 69% vs. 62%, respectively, p = 0.038) and bleeding G≥1 (61% vs. 40% vs. 25%, respectively, p≤0.001). No associations were seen for G≥1 vaginal stenosis, G≥2 dryness, G≥2 bleeding and G≥1/G≥2 mucositis.

CONCLUSION

Regular penetration (defined as vaginal dilation and/or sexual activity) was associated with lower risk for vaginal stenosis G≥2, but higher risk for vaginal dryness G≥1 and bleeding G≥1. Mild vaginal dryness seems to become apparent in particular for patients experiencing vaginal penetration. Minor vaginal blood loss during dilation and/or sexual activity is commonly reported by patients, resulting from atrophy of the vaginal mucosa and/or telangiectasia. While both of these G≥1 symptoms can be managed with lubricants, moisturizer and/or hormonal replacement therapy, G≥2 vaginal stenosis represents an irreversible fibrotic adverse event that can cause dyspareunia in many cancer patients. These long-term data support clinical recommendations for dilation and/or sexual activity after radiotherapy.

A systematic review of screening diagnostic tools for trigeminal neuralgia

Background and objective

Trigeminal neuralgia (TN) is a rare chronic neuropathic pain condition of sudden and severe pain, often described as an electric shock. Diagnosis is challenging for non-expert clinicians, particularly in primary care settings. We wanted to identify and assess the diagnostic accuracy of existing screening tools for TN and orofacial pain that could be used to support the diagnosis of TN in primary care.

Databases and data treatment

We searched key databases (MEDLINE, ASSIA, Embase, and Web of Knowledge and PsycINFO) supplemented by citation tracking from January 1988 to 2021. We used an adapted version of the Quality of Diagnostic Accuracy Studies (QUADAS-2) to assess the methodological quality of each study.

Results

Searches identified five studies, from the UK, USA and Canada; three validated self-report questionnaires; and two artificial neural networks. All screened for multiple orofacial pain diagnoses, including dentoalveolar pain, musculoskeletal pain (temporomandibular disorders) and neurological pain (trigeminal neuralgia, headache, atypical facial pain and postherpetic neuralgia). The overall quality assessment was low for one study.

Conclusions

Diagnosis of TN can be challenging for non-expert clinicians. Our review found few existing screening tools to diagnose TN, and none is currently suitable to be used in primary care settings. This evidence supports the need to adapt an existing tools or to create a new tool for this purpose. The development of an appropriate screening questionnaire could assist non-expert dental and medical clinicians to identify TN more effectively and empower them to manage or refer patients for treatment more effectively.

Non-Abelian braiding of graph vertices in a superconducting processor

Indistinguishability of particles is a fundamental principle of quantum mechanics¹. For all elementary and quasiparticles observed to date-including fermions, bosons and Abelian anyons-this principle guarantees that the braiding of identical particles leaves the system unchanged^2,3. However, in two spatial dimensions, an intriguing possibility exists: braiding of non-Abelian anyons causes rotations in a space of topologically degenerate wavefunctions^4-8. Hence, it can change the observables of the system without violating the principle of indistinguishability. Despite the well-developed mathematical description of non-Abelian anyons and numerous theoretical proposals^9-22, the experimental observation of their exchange statistics has remained elusive for decades. Controllable many-body quantum states generated on quantum processors offer another path for exploring these fundamental phenomena. Whereas efforts on conventional solid-state platforms typically involve Hamiltonian dynamics of quasiparticles, superconducting quantum processors allow for directly manipulating the many-body wavefunction by means of unitary gates. Building on predictions that stabilizer codes can host projective non-Abelian Ising anyons^9,10, we implement a generalized stabilizer code and unitary protocol²³ to create and braid them. This allows us to experimentally verify the fusion rules of the anyons and braid them to realize their statistics. We then study the prospect of using the anyons for quantum computation and use braiding to create an entangled state of anyons encoding three logical qubits. Our work provides new insights about non-Abelian braiding and, through the future inclusion of error correction to achieve topological protection, could open a path towards fault-tolerant quantum computing.

Formation of robust bound states of interacting microwave photons

Systems of correlated particles appear in many fields of modern science and represent some of the most intractable computational problems in nature. The computational challenge in these systems arises when interactions become comparable to other energy scales, which makes the state of each particle depend on all other particles1. The lack of general solutions for the three-body problem and acceptable theory for strongly correlated electrons shows that our understanding of correlated systems fades when the particle number or the interaction strength increases. One of the hallmarks of interacting systems is the formation of multiparticle bound states2-9. Here we develop a high-fidelity parameterizable fSim gate and implement the periodic quantum circuit of the spin-½ XXZ model in a ring of 24 superconducting qubits. We study the propagation of these excitations and observe their bound nature for up to five photons. We devise a phase-sensitive method for constructing the few-body spectrum of the bound states and extract their pseudo-charge by introducing a synthetic flux. By introducing interactions between the ring and additional qubits, we observe an unexpected resilience of the bound states to integrability breaking. This finding goes against the idea that bound states in non-integrable systems are unstable when their energies overlap with the continuum spectrum. Our work provides experimental evidence for bound states of interacting photons and discovers their stability beyond the integrability limit.

Noise-resilient edge modes on a chain of superconducting qubits

Inherent symmetry of a quantum system may protect its otherwise fragile states. Leveraging such protection requires testing its robustness against uncontrolled environmental interactions. Using 47 superconducting qubits, we implement the one-dimensional kicked Ising model, which exhibits nonlocal Majorana edge modes (MEMs) with ℤ 2 parity symmetry. We find that any multiqubit Pauli operator overlapping with the MEMs exhibits a uniform late-time decay rate comparable to single-qubit relaxation rates, irrespective of its size or composition. This characteristic allows us to accurately reconstruct the exponentially localized spatial profiles of the MEMs. Furthermore, the MEMs are found to be resilient against certain symmetry-breaking noise owing to a prethermalization mechanism. Our work elucidates the complex interplay between noise and symmetry-protected edge modes in a solid-state environment.

239 An Audit on The Consenting Process For Orthopaedic Surgery During The COVID Pandemic

Aim

The Royal College of Surgeons have published guidelines on consenting for treatment of patients when COVID-19 is present in society. Patients should be made aware that attending hospital for elective surgical procedures exposes them to the risk of contracting COVID-19, despite the stringent health and hygiene measures employed by hospitals and their staff. Our aim is to investigate whether orthopaedic patients are being appropriately consented for surgery during the COVID pandemic.

Method

A prospective audit of 100 consent forms was performed. The forms were examined to identify whether COVID-19 risk was documented as a potential risk of surgery. Data was also collected on consented grade, patient length of stay and any complications post-operatively.

Results

56% of consent forms reviewed did not contain the risk of COVID documented in them. 34% of forms that did not state COVID risk were completed by consultants, 18% by fellows and 48% were by registrars. 24% of these patients had an in-patient length of stay of 3 or more days. 6% patients were suspected of COVID post-operatively and tested. 0% patients contracted COVID in this cohort.

Conclusions

The Royal College of Surgeons COVID-19 Toolkit states that the risk of contracting COVID while in hospital is 0.45%. All patients should be made aware of this risk prior to proceeding with surgery. Only 44% of patients in our hospital have had this risk discussed and documented. This compliance level has to be significantly improved.

Interplay between probe design and test performance: overlap between genomic regions of interest, capture regions and high quality reference calls influence performance of WES-based assays

Whole exome sequencing (WES)-based assays undergo rigorous validation before being implemented in diagnostic laboratories. This validation process generates experimental evidence that allows laboratories to predict the performance of the intended assay. The NA12878 Genome in a Bottle (GIAB) HapMap reference sample is commonly used for validation in diagnostic laboratories. We investigated what data points should be taken into consideration when validating WES-based assays using the GIAB reference in a diagnostic setting. We delineate specific factors that require special consideration and identify OMIM genes associated with diseases that may 'bypass' validation. Four replicates of the NA12878 sample were sequenced at the CHEO Genetics Diagnostic Laboratory on a NextSeq 500; the data were analyzed using the bcbio_nexgen v1.1.2 pipeline. The hap.py validation engine, Real Time Genomics vcfeval tool, and high confidence (HC) variant calls in HC regions available for the GIAB sample were used to validate the obtained variant calls. The same validation process was then used to evaluate variant calls obtained for the same sample by two other clinical diagnostic laboratories. We showed that variant calls in NA12878 can be confidently measured only in the regions that intersect between the GIAB HC regions and the target regions of exome capture. Of the 4139 (as of October 2019) OMIM genes associated with a phenotype and having a known molecular basis of disease, 84 were fully outside of the GIAB HC regions and many of the remaining OMIM genes were only partially covered by the HC regions. A significant proportion of variants identified in the NA12878 sample outside of the HC regions have unknown (UNK) status due to the absence of HC reference alleles. Verification of such calls is possible either by an alternative truth set or by orthogonal testing. Similarly, many variants outside of exome capture regions, if not accounted for, will be deemed false negatives due to insufficient probe coverage. Our results demonstrate the importance of the intersection between genomic regions of interest, capture regions, and the high confidence regions. If not considered, false and ambiguous variant calls could have a negative impact on diagnostic accuracy of the intended WES-based diagnostic assay and increase the need for confirmatory testing. To enable laboratories to identify 'problematic' regions and optimize validation efforts, we have made our VCF and BED files available in UCSC Genome Browser: NA12878 WES Benchmark. Relevant genes and genome annotations are evolving, we implemented a general purpose algorithm to cross-reference OMIM genes with the genomic regions of interest that can be applied to capture genes/regions outside HC regions (see repository of data material section).

Early Childhood Obesity Prevention: Challenges and Barriers of Implementing Child and Adult Care Food

INTRODUCTION

The Child and Adult Care Food Program requirements promote healthy eating behaviors and increased physical activity in the daycare setting to help prevent childhood obesity. Some of these standards can be difficult to meet for early childhood education centers. This study examines the challenges and barriers daycare centers face when implementing these guidelines.

METHODS

Focus groups consisting of participants from early childhood education centers within our community were conducted in April and May of 2018.

RESULTS

Three focus groups were conducted, with a total of 7 childcare center directors. Eight themes that affect nutrition and physical activity curriculums at early childhood education centers arose: teacher philosophy and involvement, training/expertise of staff, parental involvement, financial constraints, children's interests, food availability, physical environment, and regulations/guidelines. Overall, participants expressed their sense that child care facilities are undervalued. They agreed that healthy, fresh food choices are expensive, difficult to obtain due to the volume needed, and require additional training to prepare. Emphasis on gross motor development has a varied level of support from families and teachers. Challenges and barriers to providing adequate gross motor activities include limited financial support, lack of physical space, lack of teacher willingness to engage in outdoor activity, and parental resistance.

CONCLUSIONS

Financial constraints and the "undervaluing" of childcare contribute greatly to many of the challenges and barriers early childhood education centers face in meeting nutrition and physical activity standards. Findings from this study shed light on the significant role early childcare centers play in nurturing child development and the efforts these centers undertake in the interest of children.

ALU transposition induces familial hypertrophic cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy (LVH) in the absence of predisposing cardiovascular conditions. Pathogenic variants in at least 16 cardiac sarcomeric genes have been implicated in HCM, most of which act in a dominant‐negative fashion. However loss‐of‐function (haploinsufficiency) is the most common disease mechanism for pathogenic variants in MYBPC3, suggesting that MYBPC3 complete deletion may play a role in HCM pathogenesis. Here, we investigate MYBPC3 complete deletion as a disease mechanism in HCM by analyzing two unrelated patients with confirmed diagnosis of HCM that tested negative by Sanger sequencing analysis.

Methods

MYBPC3 complete deletion was investigated by Multiplex ligation‐dependent probe amplification (MLPA) and microarray analyses. The mechanism of deletion was investigated by interrogating the SINEBase database.

Results

Patient‐1 was diagnosed with nonobstructive HCM in his mid‐40s while undergoing assessment for palpitations, and patient‐2 with obstructive HCM in his late‐20s while undergoing systolic heart murmur assessment for an unrelated illness. MLPA testing revealed a heterozygous deletion of all MYBPC3 exons in both patients. Subsequent microarray testing confirmed these deletions which extended beyond the 5′ and 3′ ends of MYBPC3. Genomic assessment suggested that these deletions resulted from Alu/Alu‐homologous recombination.

Conclusion

Our results demonstrate that haploinsufficiency resulting from MYBPC3 complete deletion, potentially mediated by Alu recombination, is an important disease mechanism in cardiomyopathy and emphasizes the importance of copy number variation analysis in patients clinically suspected of HCM.

A multicentre, clinical evaluation of a hydro-responsive wound dressing: the Glasgow experience

OBJECTIVE

Our aim was to assess the effectiveness of hydro-responsive wound dressing (HRWD) in debridement and wound bed preparation of a variety of acute and chronic wounds that presented with devitalised tissue needing removal so that healing may proceed.

METHOD

This was a non-comparative evaluation of acute and chronic wounds that required debridement as part of their normal treatment regimen. Clinicians recorded wound changes including a subjective assessment level of devitalised tissue and wound bed preparation, presence of pain, wound status (e.g., wound size) and periwound skin condition. Data was also collected from clinicians and patients to provide information on clinical performance of the dressing.

RESULTS

We recruited 100 patients with a variety of wound types into the study. Over 90% of the clinicians reported removal of devitalised tissue to enable a healing response in both chronic and acute wounds. Specifically, over the course of the evaluation period, levels of devitalised tissue (necrosis and slough) reduced from 85.5% to 26.3%, and this was accompanied by an increase in wound bed granulation from 12.0% to 33.7%. Correspondingly, there was a 40% reduction in wound area, hence a clinically relevant healing response was seen upon treatment with HRWD. It is also noteworthy that this patient population included a significant proportion of chronic wounds (51.4%) that showed no signs of wound progression within <4 weeks before study inclusion. Of these chronic wounds, 93% demonstrated wound progression upon treatment with HRWD. Despite reported pain levels being low pre- and post-dressing change, overall wound pain improved (reduced) in 48% of patients. Periwound skin condition showed a tendency towards improvement, and the fluid management capabilities of the HRWD was reported as good to excellent in the majority of cases. Wound infections were reduced by at least 60% over the evaluation period. A simple cost-effective analysis demonstrated significant savings using HRWD (£6.33) over current standard practice regimens of a four-step debridement process (£8.05), larval therapy (£306.39) and mechanical pad debridement (£11.46).

CONCLUSION

HRWD was well tolerated and was demonstrated to be an efficient debridement tool providing rapid, effective and pain free debridement in a variety of wound types.

Adopting High-Resolution Allele Frequencies Substantially Expedites Variant Interpretation in Genetic Diagnostic Laboratories

A cohort of 1242 individuals tested in a clinical diagnostic laboratory was used to test whether the filtering allele frequencies (FAFs)-based framework, recently recommended for MHY7-associated cardiomyopathy, is extendable to 45 cardiomyopathy genes. Statistical analysis revealed a threshold of 0.00164% for the extreme outlier allele frequencies (AFs), based on the Genome Aggregation Database (exome fraction) total AFs of 138 unique pathogenic and likely pathogenic variants; 135 of them (97.8%) had AFs of <0.004%, the recommended threshold to apply moderate pathogenicity evidence for MYH7-associated cardiomyopathy. Of the 460 cases reported with only variant(s) of unknown clinical significance (VUCSs), 97 (21%) solely had VUCSs with FAFs >0.03%, frequencies above which were estimated herein as strong evidence against pathogenicity. Interestingly, 74.5% (172/231) of the unique VUCSs with FAFs >0.03% had Genome Aggregation Database maximum allele frequencies across all populations AFs >0.1%, deemed herein as stand-alone evidence against pathogenicity. Accordingly, using an FAF threshold of >0.1%, compared with AF >1%, led us to issue considerably more (25.9% versus 41.3%) negative patient reports. Also, 82.7% (N = 629) of the unique classified benign or likely benign variants with AFs <1% had FAFs >0.1%, reinforcing the use of this filtering strategy. Together, these data demonstrate that implementing FAF thresholds may considerably decrease the amount of variant interpretations and significantly reduce the cost of genetic testing for clinical genetic laboratories, without compromising the accuracy of genetic diagnostic services.

Genetic Diagnostic Testing for Inherited Cardiomyopathies: Considerations for Offering Multi-Gene Tests in a Health Care Setting

Inherited cardiomyopathies (ICs) are a major cause of heart disease. Given their marked clinical and genetic heterogeneity, the content and clinical utility of IC multi-gene panels has been the topic of continuous debate. Our genetics diagnostic laboratory has been providing clinical diagnostic testing for ICs since 2012. We began by testing nine genes and expanded our panel by fivefold in 2015. Here, we describe the implementation of a cost-effective next-generation sequencing (NGS)-based assay for testing of IC genes, including a protocol that minimizes the amount of Sanger sequencing required to confirm variants identified by NGS, which reduces the cost and time of testing. The NGS assay was developed for the simultaneous analysis of 45 IC genes and was assessed for the impact of panel expansion on variant detection, turnaround time, and cost of testing in a cohort of 993 patients. The assay led to a considerable reduction in test cost and turnaround time. However, only a marginal increase was observed in the diagnostic yield, whereas the rate of inconclusive findings increased considerably. These findings suggest that the ongoing evaluation of gene content and monitoring of clinical utility for multi-gene tests are essential to achieve maximum clinical utility of multi-gene tests in a publicly funded health care setting.

Adolescent and adult differences in major depression symptom profiles

BACKGROUND

Depression is the leading global cause of disability and often begins in adolescence. The genetic architecture and treatment response profiles for adults and adolescents differ even though identical criteria are used to diagnose depression across different age groups. There is no clear consensus on how these groups differ in their symptom profiles.

METHODS

Using data from a two-generation family study, we compared the presentation of DSM-IV depressive symptoms in adolescents and adults with MDD (Major Depressive Disorder). We also compared DSM-IV depressive symptom counts using latent class analysis.

RESULTS

Vegetative symptoms (appetite and weight change, loss of energy and insomnia) were more common in adolescent MDD than adult MDD. Anhedonia/loss of interest and concentration problems were more common in adults with MDD. When using latent class analysis to look at depressive symptoms, a vegetative symptom profile was also seen in adolescent depression only.

LIMITATIONS

Adults and adolescents were recruited in different ways. Adolescent cases were more likely to be first-onset while adult cases were recurrences. It was not possible to examine how recurrence affected adolescent depression symptom profiles.

CONCLUSION

Differences in how depression presents in adolescents and adults may be consistent with different pathophysiological mechanisms. For adolescents, we found that vegetative/physical disturbances were common (loss of energy, changes in weight, appetite and sleep changes). For adults, anhedonia/loss of interest and concentration difficulties were more common.

Leveraging the power of new molecular technologies in the clinical setting requires unprecedented awareness of limitations and drawbacks: experience of one diagnostic laboratory

BACKGROUND

Advances in molecular technologies and in-silico variant prediction tools offer wide-ranging opportunities in diagnostic settings, yet they also present with significant limitations.

OBJECTIVE

Here, we contextualise the limitations of next-generation sequencing (NGS), multiplex ligation-dependent probe amplification (MLPA) and in-silico prediction tools routinely used by diagnostic laboratories by reviewing specific experiences from our diagnostic laboratory.

METHODS

We investigated discordant annotations and/or incorrect variant 'callings' in exons of 56 genes constituting our cardiomyopathy and connective tissue disorder NGS panels. Discordant variants and segmental duplications (SD) were queried using the National Center for Biotechnology Information (NCBI) Basic Local Alignment Search Tool and the University of California Santa Cruz genome browser, respectively, to identify regions of high homology. Discrepant variant analyses by in-silico models were re-evaluated using updated file entries.

RESULTS

We observed a 5% error rate in MYH7 variant 'calling' using MLPA, which resulted from >90% homology of the MYH7 probe-binding site to MYH6. SDs were detected in TTN, PKP2 and MYLK. SDs in MYLK presented the highest risk (15.7%) of incorrect variant 'calling'. The inaccurate 'callings' and discrepant in-silico predictions were resolved following detailed investigation into the source of error.

CONCLUSION

Recognising the limitations described here may help avoid incorrect diagnoses and leverage the power of new molecular technologies in diagnostic settings.

Can rescuers accurately deliver subtle changes to chest compression depth if recommended by future guidelines?

BACKGROUND

A recent study reported that a compression depth of 4.56 cm optimised survival following cardiac arrest, which is at variance with the current guidelines of 5.0-6.0 cm. A reduction in recommended compression depth is only likely to improve survival if healthcare professionals can accurately deliver a relatively small change in target depth. This study aimed to determine if healthcare professionals could accurately judge their delivered compression depth by 0.5 cm increments.

METHOD

This randomised interventional trial asked BLS-trained healthcare professionals to complete two minutes of continuous chest compressions on an adult manikin, randomised (without any feedback device), to compress to one of three target depth ranges of 4.0-5.0 cm, 4.5-5.5 cm or 5.0-6.0 cm, at the recommended rate of 100-120 compressions min^-1. Basic demographic data, compression rate, and compression depth were recorded.

RESULTS

One hundred and one participants were recruited, of whom one withdrew. Median depths of 3.66 cm (IQR: 3.37-4.16 cm), 4.13 cm (IQR: 3.65-4.36 cm) and 4.76 cm (IQR: 4.16-5.24 cm) were found for the target depths of 4.0-5.0 cm (n = 30), 4.5-5.5 cm (n = 35) and 5.0-6.0 cm (n = 35) respectively (P < 0.001). Overall, 18 participants successfully compressed to their target depth.

CONCLUSIONS

Rescuers are able to judge 0.5 cm differences in compression depth with precision, but remain unable to accurately judge overall target depth. Reducing the current recommended compression depth to 4.56 cm is likely to result in delivered compressions significantly below the optimal depth.

The developing shoulder has a limited capacity to recover after a short duration of neonatal paralysis

Mechanical stimuli are required for the proper development of the musculoskeletal system. Removal of muscle forces during fetal or early post-natal timepoints impairs the formation of bone, tendon, and their attachment (the enthesis). The goal of the current study was to examine the capacity of the shoulder to recover after a short duration of neonatal rotator cuff paralysis, a condition mimicking the clinical condition neonatal brachial plexus palsy. We asked if reapplication of muscle load to a transiently paralyzed muscle would allow for full recovery of tissue properties. CD-1 mice were injected with botulinum toxin A to paralyze the supraspinatus muscle from birth through 2 weeks and subsequently allowed to recover. The biomechanics of the enthesis was determined using tensile testing and the morphology of the shoulder joint was determined using microcomputed tomography and histology. A recovery period of at least 10 weeks was required to achieve control properties, demonstrating a limited capacity of the shoulder to recover after only two weeks of muscle paralysis. Although care must be taken when extrapolating results from an animal model to the human condition, the results of the current study imply that treatment of neonatal brachial plexus palsy should be aggressive, as even short periods of paralysis could lead to long-term deficiencies in enthesis biomechanics and shoulder morphology.

The effect of suture caliber and number of core suture strands on zone II flexor tendon repair: a study in human cadavers

PURPOSE

To compare the tensile properties of a 3-0, 4-strand flexor tendon repair with a 4-0, 4-strand repair and a 4-0, 8-strand repair.

METHODS

Following evaluation of the intrinsic material properties of the 2 core suture calibers most commonly used in tendon repair (3-0 and 4-0), we tested the mechanical properties of 40 cadaver flexor digitorum profundus tendons after zone II repair with 1 of 3 techniques: a 3-0, 4-strand core repair, a 4-0, 8-strand repair, or a 4-0, 4-strand repair. We compared results across suture caliber for the 2 sutures and across tendon repair methods.

RESULTS

Maximum load to failure of 3-0 polyfilament caprolactam suture was 49% greater than that of 4-0 polyfilament caprolactam suture. The cross-sectional area of 3-0 polyfilament caprolactam was 42% greater than that of 4-0 polyfilament caprolactam. The 4-0, 8-strand repair produced greater maximum load to failure when compared with the 2 4-strand techniques. Load at 2-mm gap, stiffness, and work to yield were significantly greater in the 4-0, 8-strand repair than in the 3-0, 4-strand repair.

CONCLUSIONS

In an ex vivo model, an 8-strand repair using 4-0 suture was 43% stronger than a 4-strand repair using 3-0 suture, despite the finding that 3-0 polyfilament caprolactam was 49% stronger than 4-0 polyfilament caprolactam. These results suggest that, although larger-caliber suture has superior tensile properties, the number of core suture strands across a repair site has an important effect on time zero, ex vivo flexor tendon repair strength.

CLINICAL RELEVANCE

Surgeons should consider using techniques that prioritize multistrand core suture repair over an increase in suture caliber.

Exercise for depression in care home residents: a randomised controlled trial with cost-effectiveness analysis (OPERA)

BACKGROUND

Many older people living in care homes (long term residential care or nursing homes) are depressed. Exercise is a promising non-drug intervention for preventing and treating depression in this population.

OBJECTIVE

To evaluate the impact of a 'whole-home' intervention, consisting of training for residential and nursing home staff backed up with a twice-weekly, physiotherapist-led exercise class on depressive symptoms in care home residents.

DESIGN

A cluster randomised controlled trial with a cost-effectiveness analysis to compare (1) the prevalence of depression in intervention homes with that in control homes in all residents contributing data 12 months after homes were randomised (cross-sectional analysis); (2) the number of depressive symptoms at 6 months between intervention and control homes in residents who were depressed at pre-randomisation baseline assessment (depressed cohort comparison); and (3) the number of depressive symptoms at 12 months between intervention and control homes in all residents who were present at pre-randomisation baseline assessment (cohort comparison).

SETTING

Seventy-eight care homes in Coventry and Warwickshire and north-east London.

PARTICIPANTS

Care home residents aged ≥ 65 years.

INTERVENTIONS

Control intervention: Depression awareness training programme for care home staff. Active intervention: A 'whole-home' exercise intervention, consisting of training for care home staff backed up with a twice-weekly, physiotherapist-led exercise group.

MAIN OUTCOME MEASURES

Geriatric Depression Scale-15, proxy European Quality of Life-5 Dimensions (EQ-5D), cost-effectiveness from an National Health Service perspective, peripheral fractures and death.

RESULTS

We recruited a total of 1054 participants. Cross-sectional analysis: We obtained 595 Geriatric Depression Scale-15 scores and 724 proxy EQ-5D scores. For the cohort analyses we obtained 765 baseline Geriatric Depression Scale-15 scores and 776 proxy EQ-5D scores. Of the 781 who we assessed prior to randomisation, 765 provided a Geriatric Depression Scale-15 score. Of these 374 (49%) were depressed and constitute our depressed cohort. Resource-use and quality-adjusted life-year data, based on proxy EQ-5D, were available for 798 residents recruited prior to randomisation. We delivered 3191 group exercise sessions with 31,705 person attendances and an average group size of 10 (5.3 study participants and 4.6 non-study participants). On average, our participants attended around half of the possible sessions. No serious adverse events occurred during the group exercise sessions. In the cross-sectional analysis the odds for being depressed were 0.76 [95% confidence interval (CI) 0.53 to 1.09] lower in the intervention group at 12 months. The point estimates for benefit for both the cohort analysis (0.13, 95% CI -0.33 to 0.60) and depressed cohort (0.22, 95% CI -0.52 to 0.95) favoured the control intervention. There was no evidence of differences in fracture rates or mortality (odds ratio 1.07, 95% CI 0.79 to 1.48) between the two groups. There was no evidence of differences in the other outcomes between the two groups. Economic analysis: The additional National Health Service cost of the OPERA intervention was £374 per participant (95% CI -£655 to £1404); the mean difference in quality-adjusted life-year was -0.0014 (95% CI -0.0728 to 0.0699). The active intervention was thus dominated by the control intervention, which was more effective and less costly.

CONCLUSION

The results do not support the use of a whole-home physical activity and moderate-intensity exercise programme to reduce depression in care home residents.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN43769277.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 17, No. 18. See the Health Technology Assessment programme website for further project information.

Effect of bone morphogenetic protein 2 on tendon-to-bone healing in a canine flexor tendon model

Tendon-to-bone healing is typically poor, with a high rate of repair-site rupture. Bone loss after tendon-to-bone repair may contribute to poor outcomes. Therefore, we hypothesized that the local application of the osteogenic growth factor bone morphogenetic protein 2 (BMP-2) would promote bone formation, leading to improved repair-site mechanical properties. Intrasynovial canine flexor tendons were injured in Zone 1 and repaired into bone tunnels in the distal phalanx. BMP-2 was delivered to the repair site using either a calcium phosphate matrix (CPM) or a collagen sponge (COL) carrier. Each animal also received carrier alone in an adjacent repair to serve as an internal control. Repairs were evaluated at 21 days using biomechanical, radiographic, and histologic assays. Although an increase in osteoid formation was noted histologically, no significant increases in bone mineral density occurred. When excluding functional failures (i.e., ruptured and gapped repairs), mechanical properties were not different when comparing BMP-2/CPM groups with carrier controls. A significantly higher percentage of BMP-2 treated specimens had a maximum force <20 N compared to carrier controls. While tendon-to-bone healing can be enhanced by addressing the bone loss that typically occurs after surgical repair, the delivery of BMP-2 using the concentrations and methods of the current study did not improve mechanical properties over carrier alone. The anticipated anabolic effect of BMP-2 was insufficient in the short time frame of this study to counter the post-repair loss of bone.

Intrasynovial flexor tendon repair: a biomechanical study of variations in suture application in human cadavera

To improve the functional outcomes of intrasynovial tendon suture, prior experiments evaluated individual technical modifications used in the repair process. Few studies, however, have assessed the combinatorial effects of those suture modifications in an integrated biomechanical manner, including a sample size sufficient to make definitive observations on repair technique. Two hundred fifty-six flexor tendon repairs were performed in human cadavera, and biomechanical properties were determined. The effects of five factors for flexor tendon repair were tested: core suture caliber (4-0 or 3-0), number of sutures crossing the repair site (four- or eight-strand), core suture purchase (0.75 or 1.2 cm), peripheral suture caliber (6-0 or 5-0), and peripheral suture purchase (superficial or 2 mm). Significant factors affecting the properties of the repair were the number of core suture strands and the peripheral suture purchase. The least significant factors were core suture purchase and peripheral suture caliber. The choice of core suture caliber affected the properties of repair marginally. Based on these results, we recommend that surgeons continue to focus on multi-strand repair methods, as the properties of eight-strand repairs were far better than those of four-strand repairs. To resist gap formation and enhance repair strength, a peripheral suture with 2 mm purchase is also recommended. Finally, since core suture caliber affected some biomechanical properties, including the failure mode, a 3-0 suture could be considered, provided that future in vivo studies can confirm that gliding properties are not adversely influenced.

A multicentred randomised controlled trial of a primary care-based cognitive behavioural programme for low back pain. The Back Skills Training (BeST) trial

OBJECTIVES

To estimate the clinical effectiveness of active management (AM) in general practice versus AM plus a group-based, professionally led cognitive behavioural approach (CBA) for subacute and chronic low back pain (LBP) and to measure the cost of each strategy over a period of 12 months and estimate cost-effectiveness.

DESIGN

Pragmatic multicentred randomised controlled trial with investigator-blinded assessment of outcomes.

SETTING

Fifty-six general practices from seven English regions.

PARTICIPANTS

People with subacute and chronic LBP who were experiencing symptoms that were at least moderately troublesome.

INTERVENTIONS

Participants were randomised (in a ratio of 2:1) to receive either AM+CBA or AM alone.

MAIN OUTCOME MEASURES

Primary outcomes were the Roland Morris Disability Questionnaire (RMQ) and the Modified Von Korff Scale (MVK), which measure LBP and disability. Secondary outcomes included mental and physical health-related quality of life (Short Form 12-item health survey), health status, fear avoidance beliefs and pain self-efficacy. Cost-utility of CBA was considered from both the UK NHS perspective and a broader health-care perspective, including both NHS costs and costs of privately purchased goods and services related to LBP. Quality-adjusted life-years (QALYs) were calculated from the five-item EuroQoL.

RESULTS

Between April 2005 and April 2007, 701 participants were randomised: 233 to AM and 468 to AM+CBA. Of these, 420 were female. The mean age of participants was 54 years and mean baseline RMQ was 8.7. Outcome data were obtained for 85% of participants at 12 months. Benefits were seen across a range of outcome measures in favour of CBA with no evidence of group or therapist effects. CBA resulted in at least twice as much improvement as AM. Mean additional improvement in the CBA arm was 1.1 [95% confidence interval (CI) 0.4 to 1.7], 1.4 (95% CI 0.7 to 2.1) and 1.3 (95% CI 0.6 to 2.1) change points in the RMQ at 3, 6 and 12 months respectively. Additional improvement in MVK pain was 6.8 (95% CI 3.5 to 10.2), 8.0 (95% CI 4.3 to 11.7) and 7.0 (95% CI 3.2 to 10.7) points, and in MVK disability was 4.3 (95% CI 0.4 to 8.2), 8.1 (95% CI 4.1 to 12.0) and 8.4 (95% CI 4.4 to 12.4) points at 3, 6 and 12 months respectively. At 12 months, 60% of the AM+CBA arm and 31% of the AM arm reported some or complete recovery. Mean cost of attending a CBA course was 187 pounds per participant with an additional benefit in QALYs of 0.099 and an additional cost of 178.06 pounds. Incremental cost-effectiveness ratio was 1786.00 pounds. Probability of CBA being cost-effective reached 90% at about 3000 pounds and remained at that level or above; at a cost-effectiveness threshold of 20,000 pounds the CBA group had an almost 100% probability of being considered cost-effective. User perspectives on the acceptability of group treatments were sought through semi-structured interviews. Most were familiar with key messages of AM; most who had attended any group sessions had retained key messages from the sessions and two-thirds talked about a reduction in fear avoidance and changes in their behaviour. Group sessions appeared to provide reassurance, lessen isolation and enable participants to learn strategies from each other.

CONCLUSIONS

Long-term effectiveness and cost-effectiveness of CBA in treating subacute and chronic LBP was shown, making this intervention attractive to patients, clinicians and purchasers. Short-term (3-month) clinical effects were similar to those found in high-quality studies of other therapies and benefits were maintained and increased over the long term (12 months). Cost per QALY was about half that of competing interventions for LBP and because the intervention can be delivered by existing NHS staff following brief training, the back skills training programme could be implemented within the NHS with relative ease.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN37807450.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.