MicroRNA Signatures of the Developing Primate Fovea

Rod and cone photoreceptors differ in their shape, photopigment expression, synaptic connection patterns, light sensitivity, and distribution across the retina. Although rods greatly outnumber cones, human vision is mostly dependent on cone photoreceptors since cones are essential for our sharp visual acuity and color discrimination. In humans and other primates, the fovea centralis (fovea), a specialized region of the central retina, contains the highest density of cones. Despite the vast importance of the fovea for human vision, the molecular mechanisms guiding the development of this region are largely unknown. MicroRNAs (miRNAs) are small post-transcriptional regulators known to orchestrate developmental transitions and cell fate specification in the retina. Here, we have characterized the transcriptional landscape of the developing rhesus monkey retina. Our data indicates that non-human primate fovea development is significantly accelerated compared to the equivalent retinal region at the other side of the optic nerve head, as described previously. Notably, we also identify several miRNAs differentially expressed in the presumptive fovea, including miR-15b-5p, miR-342-5p, miR-30b-5p, miR-103-3p, miR-93-5p as well as the miRNA cluster miR-183/-96/-182. Interestingly, miR-342-5p is enriched in the nasal primate retina and in the peripheral developing mouse retina, while miR-15b is enriched in the temporal primate retina and increases over time in the mouse retina in a central-to-periphery gradient. Together our data constitutes the first characterization of the developing rhesus monkey retinal miRNome and provides novel datasets to attain a more comprehensive understanding of foveal development.

Opium tincture for opioid substitution treatment

Introduction

Opium tincture (OT) is widely used for opioid substitution treatment (OST) in Iran.

Objectives

To determine if OT is a safe and effective medication for OST.

Methods

Opium Trial was a multicenter, double‐blind, noninferiority randomized controlled trial, with 204 participants with opioid dependence in Iran. Participants were then randomized to OT or methadone arms with an allocation ratio of 1:1 and were followed for 12 weeks. The primary outcome was retention in treatment, compared between the two groups using both intention-To-Treat (ITT) and Per-Protocol (PP) analyses.

Results

A total of 70 participants (IT: 68.6%, PP: 69.3%) in methadone arm and 61 participants (ITT: 59.8%, PP: 60.4%) in OT arm remained in the treatment. The relative retention rate was 1.15 (0.97, 1.36) in both analyses in favour of methadone. A total of 46 out of 152 (30.3%) participants in OT arm and 83 out of 168 (49.4%) participants in methadone arm reported opioid use outside the treatment. The difference in these two proportions (OT - methadone) was 19%: (10%, 28%) in favour of OT. The proportion of patients with adverse events were not different between the two arms (P = 0.06). There was no serious AE in OT arm.

Conclusions

Opium tincture is a clinically effective and safe medication, but this study could not conclude if it was as equally effective as methadone in retaining participants in treatment, but it showed that OT was superior to methadone in reducing opioid use outside the treatment.

Disclosure

No significant relationships.

Risk and protective factors for opioid overdose during the COVID-19 pandemic

Introduction

People who use drugs (PWUD) are now at the intersection of two public health emergencies – the Covid-19 pandemic and the overdose crisis. They may be at heightened risk of overdose due to increased isolation, worsened mental health, and changes to the illicit drug supply. The province of British Columbia (BC) in Canada is anticipated to experience a record-breaking year of overdose deaths as over 1,500 people (32.9 deaths per 100,000) have died from overdose in 2020. In response, BC released new clinical guidelines in March to allow the prescribing of pharmaceutical alternatives aiming to reduce PWUD’s risk of overdose and contracting Covid-19.

Objectives

We examined the risk and protective factors for overdose during these dual crises. We explored how the Covid-19 pandemic has impacted the mental health and substance use of PWUD and their access to treatment and harm reduction services.

Methods

We are conducting a survey among patients with opioid use disorder at a major hospital in Vancouver, BC. It includes the following domains: sociodemographic characteristics; mental and physical health; substance use patterns; opioid overdose history; access to treatment, harm reduction services; impacts of Covid-19.

Results

We anticipate collecting data from 200 participants. Descriptive statistics and regression analysis will be conducted to describe the sample and determine the risk, protective factors for overdose.

Conclusions

We will gain a better understanding of overdose risk in PWUD who are now navigating the complex challenges created by the dual crises. This will in turn inform the establishment of evidence-based strategies to reduce their overdose risk.

Disclosure

No significant relationships.

Health Science Students as PPE Coaches in the Emergency Department - a Pandemic Pilot Project

PPE is an integral part of reducing transmission of COVID-19. We assessed a 5-week pilot project of utilising health science student volunteers as PPE coaches in the adult and paediatric emergency department (ED) during the pandemic. PPE coaches were provided with training, PPE checklist, area for written observations, and feedback surveys. Overall, correct PPE use improved over time. Coaches felt safe, that training was adequate, and part of the team. Factors that contributed to project effectiveness included institutional support, role clarification, and continuous feedback from staff. Our findings support the utilisation of students in IPC projects.

Influences on myocardial perfusion in non-obstructive coronary disease: an observational quantitative perfusion mapping study

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This study was supported by a Clinical Training Research Fellowship (K. Knott) from the British Heart Foundation and directly and indirectly from the Biomedical Research Centre at University College London Hospitals and Barts Heart Centre.

Background

Cardiovascular magnetic resonance (CMR) with automated inline perfusion mapping permits rapid fully automated non-invasive myocardial blood flow (MBF, ml/g/min). Understanding the microvascular component of MBF would help optimize epicardial coronary artery disease detection and potentially serve as an independent diagnostic / therapeutic target. 

Purpose

To explore MBF influences at stress and rest in patients with unobstructed epicardial coronary arteries.

Methods

242 participants (mean age 56.9 years) from 5 European centers with unobstructed epicardial coronary arteries and no myocardial scar underwent adenosine vasodilator perfusion mapping at stress and rest. The factors influencing MBF were determined using univariate and multivariate linear regression analyses.

Results

Mean rest perfusion was 0.91+/-0.24ml/g/min. Rest perfusion was higher in females (0.97+/-0.22ml/g/min vs 0.83 +/- 0.24ml/g/min) and lower in patients on beta blockers. Mean stress MBF was 2.53+/-0.82ml/g/min. Factors independently associated with reduced stress MBF were increasing age, diabetes, increasing left ventricular mass (LVMi) and the use of beta blockers.  The predicted stress MBF can be obtained from the equation MBF = 2.66–0.015(age-60)–0.013(LVMi-57)-0.405(diabetes)–0.365(beta blocker). This means stress MBF falls 10% over 19 years and that diabetes drops the MBF by the equivalent of being 27 years older. These changes are large: for example, a 70-year-old diabetic would have 30% lower stress MBF than a 35 year-old non-diabetic. 

Conclusions

In the absence of obstructive epicardial coronary disease, stress MBF falls with age, diabetes, increased LV mass and beta-blockers. These data may help develop normal reference ranges, input to other modelling (eg CT FFR), and they advance perfusion mapping as a measure of microvascular function.

Abstract Figure. Summary of the determinants of perfusion

Perceived barriers and enablers to physical activity participation in people with Alopecia Areata: a constructivist grounded theory study

BACKGROUND

Alopecia Areata (AA) is an autoimmune disease that is characterised by hair loss. Individuals diagnosed with it often describe feelings of trauma and social rejection due to cosmetic repercussions and are at high risk of experiencing psychological distress. Physical activity (PA) participation has been associated with better mental health outcomes in diverse populations. A preliminary study of individuals with AA indicated that severe hair loss is associated with symptomatic depression, anxiety and stress, which negatively impacted PA participation. While strategies to increase PA participation in the general population have been established, little is known about PA participation in people with AA. This study aimed to understand barriers and enablers to PA participation in people with AA to inform the development of evidence-based interventions.

METHODS

The study used a grounded theory (GT) methodology, relying on an iterative and simultaneous process of data collection, coding, theory development, and data comparisons to explore the perceived barriers and enablers to PA. Data were collected through a focus group (8 participants [33.38 ± 10.81 years]) and individual telephone interviews (8 participants [33.89 ± 11.87 years]). The study was conducted in Melbourne, Australia. Interview data were recorded digitally, transcribed verbatim and analysed. Recruitment continued until theoretical saturation was achieved.

RESULTS

The constructivist grounded theory method used has assisted to develop an explanatory model which is used to explain the themes for barriers and enablers to PA participation. The four phases in the explanatory model are as follows (1) onset of AA; (2) reaction towards the condition; (3) adjustment; and (4) acceptance.

CONCLUSION

The findings highlighted perceived barriers and enablers to PA participation in people with AA. Future interventions could consider addressing these barriers specifically to maximise effectiveness and to improve mental health status based on the phases of the explanatory model.

Radial Spin Texture of the Weyl Fermions in Chiral Tellurium

Trigonal tellurium, a small-gap semiconductor with pronounced magneto-electric and magneto-optical responses, is among the simplest realizations of a chiral crystal. We have studied by spin- and angle-resolved photoelectron spectroscopy its unconventional electronic structure and unique spin texture. We identify Kramers-Weyl, composite, and accordionlike Weyl fermions, so far only predicted by theory, and show that the spin polarization is parallel to the wave vector along the lines in k space connecting high-symmetry points. Our results clarify the symmetries that enforce such spin texture in a chiral crystal, thus bringing new insight in the formation of a spin vectorial field more complex than the previously proposed hedgehog configuration. Our findings thus pave the way to a classification scheme for these exotic spin textures and their search in chiral crystals.

Evidence for abnormal deformational reserve in hypertrophic obstructive cardiomyopathy on exercise: is this a true fingerprint?

 

Hypertrophic obstructive cardiomyopathy (HOCM) is characterized by muscle hypertrophy and fibrosis, interfering with force generation and relaxation. Abnormal ventricular (LV) myocardial deformation have been demonstrated in patients with HOCM at rest, but there is lack of data regarding the deformational mechanics in exercise in obstructive HCM.

Aims

To assess the adaptability of LV deformational behaviour to physical exercise in HOCM patients as compared to healthy controls and to examine if Deformational Imaging (DMI) can provide additional information.

Methods

28 obstructive HOCM (age 51.2±14.2yrs; 16 men, LVOT-obstruction 56±19mmHg at rest or on Valsalva maneuver) and 32 control subjects (50.9±6.8 yrs, 19 men from the MAGYAR-PATH Registry) underwent bicycle stress Echo (ESE) with full conventional 2D- and Doppler TTE, 2D- and 3D-Speckle Tracking Analysis (DMI) and 3D-Full Volume assessment both at rest and on submaximal ESE.

Results

At rest, the HOCM group had lower GLS (−14.6±4.5 vs 18.4±2.6%, p<0.01) but higher CS (−32.9±5.1 vs 28.8±2.3%) and Twist (9.9±2.6 vs 6.1±2.2°) than in control subjects. Exercise induced an increase in all strains in control subjects but less in HOCM (GLS: −21.4±3.5 vs 15.1±3.0% and CS: −33.9±3.6 vs 34.1±4.2% in controls). The increase of LV twist was blunted in HOCM (Δ1.2 vs Δ3.6° in controls). The PSS was more pronounced in HOCM on ESE (46.6±12.0 vs 21.2±9.6%, AUC: 0.71 for predicting HOCM), the UTR was slower (118±2.1 vs 133.1±14.1°/s) and occurred later in HOCM. The MD of Strain increased in HOCM on ESE (Δ85.1 vs Δ8.1ms in controls). The Twist had positive correlation with LVOT-obstruction (R2=0.54, p<0.01) and inverse correlation with UTR (R2=−0.72, p<0.02). The UTR/Twist ratio diminished only in HOCM on exercise (−6.0±0.8 vs −13.1±2.5 1/s). The MD, the PSS on ESE and the UTR/Twist ratio predicted the HOCM deformation phenotype accurately (AUC: 0.72, cut-off 6.0 1/s).

Conclusions

The HOCM patients had attenuated Strain and Rotational response on exercise implying impaired deformational adaptability with post-systolic shortening and pronounced mechanical dispersion of peak Strain on exercise which was more accurate to identify the HOCM phenotype than other Echo-indices. These findings support evidence for reduced systolic-diastolic coupling efficiency in HOCM patients on exercise which can contribute to the development of exercise-related breathlessness, dynamic LVOT-obstruction and arrhythmias in patients with HOCM. These distinct deformational patterns on exercise can help in the differential diagnosis of patients with LV hypertrophy of unknown aetiology with good sensitivity and specificity and can also aid in the risk stratification workup in HOCM.

DMI Predictors for HOCM

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Milton Keynes University Hospital Research Founding