Factors associated with plans for early retirement among Ontario family physicians during the COVID-19 pandemic: a cross-sectional study.

BACKGROUND: Higher numbers of family physicians (FPs) stopped practicing or retired during the COVID-19 pandemic, worsening the family doctor shortage in Canada. Our study objective was to determine which factors were associated with FPs' plans to retire earlier during the COVID-19 pandemic. METHODS: We administered two cross-sectional online surveys to Ontario FPs asking whether they were "planning to retire earlier" as a result of the pandemic during the first and third COVID-19 pandemic waves (Apr-Jun 2020 and Mar-Jul 2021). We used logistic regression to determine which factors were associated with early retirement planning, adjusting for age. RESULTS: The age-adjusted proportion of FP respondents planning to retire earlier was 8.2% (of 393) in the first-wave and 20.5% (of 454) in the third-wave. Planning for earlier retirement during the third-wave was associated with age over 50 years (50-59 years odds ratio (OR) 5.37 (95% confidence interval (CI):2.33-12.31), 60 years and above OR 4.18 (95% CI: 1.90-10.23)), having difficulty handling increased non-clinical responsibilities (OR 2.95 (95% CI: 1.79-4.94)), feeling unsupported to work virtually (OR 1.96 (95% CI: 1.19-3.23)) or in-person (OR 2.70 (95% CI: 1.67-4.55)), feeling unable to provide good care (OR 1.82 (95% CI: 1.10-3.03)), feeling work was not valued (OR 1.92 (95% CI: 1.15-3.23)), feeling frightened of dealing with COVID-19 (OR 2.01 (95% CI: 1.19-3.38)), caring for an elderly relative (OR 2.36 (95% CI: 1.69-3.97)), having difficulty obtaining personal protective equipment (OR 2.00 (95% CI: 1.16-3.43)) or difficulty implementing infection control practices in clinic (OR 2.10 (95% CI: 1.12-3.89)). CONCLUSIONS: Over 20% of Ontario FP respondents were considering retiring earlier by the third-wave of the COVID-19 pandemic. Supporting FPs in their clinical and non-clinical roles, such that they feel able to provide good care and that their work is valued, reducing non-clinical (e.g., administrative) responsibilities, dealing with pandemic-related fears, and supporting infection control practices and personal protective equipment acquisition in clinic, particularly in those aged 50 years or older may help increase family physician retention during future pandemics.

A team of chaperones play to win in the bacterial periplasm.

The survival and virulence of Gram-negative bacteria require proper biogenesis and maintenance of the outer membrane (OM), which is densely packed with ß-barrel OM proteins (OMPs). Before reaching the OM, precursor unfolded OMPs (uOMPs) must cross the whole cell envelope. A network of periplasmic chaperones and proteases maintains unfolded but folding-competent conformations of these membrane proteins in the aqueous periplasm while simultaneously preventing off-pathway aggregation. These periplasmic proteins utilize different strategies, including conformational heterogeneity, oligomerization, multivalency, and kinetic partitioning, to perform and regulate their functions. Redundant and unique characteristics of the individual periplasmic players synergize to create a protein quality control team capable responding to changing environmental stresses.

Integration of hospital with congregate care homes in response to the COVID-19 pandemic.

Background: The coronavirus disease 2019 (COVID-19) pandemic has highlighted the need to improve the safety of the environments where we care for older adults in Canada. After providing assistance during the first wave, many Ontario hospitals formally partnered with local congregate care homes in a "hub and spoke" model during second pandemic wave onward. The objective of this article is to describe the implementation and longitudinal outcomes of residents in one hub and spoke model composed of a hospital partnered with 18 congregate care homes including four long-term care and 14 retirement or other congregate care homes. Intervention: Homes were provided continuous seven-day per week access to hospital support, including infection prevention and control (IPAC), testing, vaccine delivery and clinical support as needed. Any COVID-19 exposure or transmission triggered a same-day meeting to implement initial control measures. A minimum of weekly on-site visits occurred for long-term care homes and biweekly for other congregate care homes, with up to daily on-site presence during outbreaks. Outcomes: Case detection among residents increased following implementation in context of increased testing, then decreased post-immunization until the Omicron wave when it peaked. After adjusting for the correlation within homes, COVID-related mortality decreased following implementation (OR=0.51, 95% CI, 0.30-0.88; p=0.01). In secondary analysis, homes without pre-existing IPAC programs had higher baseline COVID-related mortality rate (OR=19.19, 95% CI, 4.66-79.02; p<0.001) and saw a larger overall decrease during implementation (3.76% to 0.37%-0.98%) as compared to homes with pre-existing IPAC programs (0.21% to 0.57%-0.90%). Conclusion: The outcomes for older adults residing in congregate care homes improved steadily throughout the COVID-19 pandemic. While this finding is multifactorial, integration with a local hospital partner supported key interventions known to protect residents.

Conscientious, competent and caring: producing the junior doctor of the future.

This article is based on the Association for the Study of Medical Education Gold Medal Plenary for 2022, given by the first author. It outlines different ways in which medical training can be approached, based on his career and his work with colleagues. Among the attributes that it would be desirable to promote in future doctors are conscientiousness, competence and care for patients as individuals. This article explores each of these in separate sections. The first demonstrates that the trait of conscientiousness can be observed in first and second year medical students by their compliance in routine low level tasks such as attendance and submission of required work on time. A 'conscientiousness index' calculated on this basis is a statistically significant predictor of later events such as performance in exams, the prescribing safety assessment, and the UK situational judgement test in subsequent years, and also in postgraduate assessments such as Royal college exams and the annual reviews of competence progression. The second proposes that competence in tasks undertaken by junior doctors is better achieved by teaching on medical imaging, clinical skills and living anatomy than by cadaveric dissection. The final section argues that the incorporation of arts and humanities teaching into medical education is likely to lead to better understanding of the patient perspective in later practice.

The association between immigration status and the development of type 2 diabetes in women with a prior diagnosis of gestational diabetes: A population-based study.

AIMS: The aim of this study was to examine the influence of immigration status and region of origin on the risk of type 2 diabetes in women with prior gestational diabetes (GDM). METHODS: This retrospective population-based cohort study included women with gestational diabetes (GDM) aged 16 to 50 years in Ontario, Canada, who gave birth between 2006 and 2014. We compared the incidence of type 2 diabetes after delivery between long-term residents and immigrants-overall, by time since immigration and by region of-using Cox regression adjusted for age, year, neighbourhood income, rurality, infant birth weight and presence of hypertensive disorders of pregnancy (HDP). RESULTS: Among 38,515 women with prior GDM (42% immigrants), immigrants had a significantly higher risk of type 2 diabetes compared with long-term residents (adjusted hazard ratio [HR] 1.19, 95% confidence interval [CI] 1.13-1.26), with no meaningful difference based on time since immigration. The highest adjusted relative risks of type 2 diabetes compared with long-term residents were found for immigrants from Sub-Saharan Africa (HR 1.63, 95% CI 1.40-1.90), Latin America/Caribbean (HR 1.44, 95% CI 1.28-1.62) and South Asia (HR 1.34, 95% CI 1.25-1.44). CONCLUSIONS: Immigration is associated with a significantly higher risk of type 2 diabetes after GDM, particularly for women from certain low- and middle-income countries. Diabetes prevention strategies will need to consider the unique needs of immigrants from these regions.

Generation of unfolded outer membrane protein ensembles defined by hydrodynamic properties.

Outer membrane proteins (OMPs) must exist as an unfolded ensemble while interacting with a chaperone network in the periplasm of Gram-negative bacteria. Here, we developed a method to model unfolded OMP (uOMP) conformational ensembles using the experimental properties of two well-studied OMPs. The overall sizes and shapes of the unfolded ensembles in the absence of a denaturant were experimentally defined by measuring the sedimentation coefficient as a function of urea concentration. We used these data to model a full range of unfolded conformations by parameterizing a targeted coarse-grained simulation protocol. The ensemble members were further refined by short molecular dynamics simulations to reflect proper torsion angles. The final conformational ensembles have polymer properties different from unfolded soluble and intrinsically disordered proteins and reveal inherent differences in the unfolded states that necessitate further investigation. Building these uOMP ensembles advances the understanding of OMP biogenesis and provides essential information for interpreting structures of uOMP-chaperone complexes.

FkpA enhances membrane protein folding using an extensive interaction surface.

Outer membrane protein (OMP) biogenesis in gram-negative bacteria is managed by a network of periplasmic chaperones that includes SurA, Skp, and FkpA. These chaperones bind unfolded OMPs (uOMPs) in dynamic conformational ensembles to suppress aggregation, facilitate diffusion across the periplasm, and enhance folding. FkpA primarily responds to heat-shock stress, but its mechanism is comparatively understudied. To determine FkpA chaperone function in the context of OMP folding, we monitored the folding of three OMPs and found that FkpA, unlike other periplasmic chaperones, increases the folded yield but decreases the folding rate of OMPs. The results indicate that FkpA behaves as a chaperone and not as a folding catalyst to influence the OMP folding trajectory. Consistent with the folding assay results, FkpA binds all three uOMPs as determined by sedimentation velocity (SV) and photo-crosslinking experiments. We determine the binding affinity between FkpA and uOmpA171 by globally fitting SV titrations and find it to be intermediate between the known affinities of Skp and SurA for uOMP clients. Notably, complex formation steeply depends on the urea concentration, suggesting an extensive binding interface. Initial characterizations of the complex using photo-crosslinking indicate that the binding interface spans the entire FkpA molecule. In contrast to prior findings, folding and binding experiments performed using subdomain constructs of FkpA demonstrate that the full-length chaperone is required for full activity. Together these results support that FkpA has a distinct and direct effect on OMP folding that it achieves by utilizing an extensive chaperone-client interface to tightly bind clients.

Revisiting macromolecular hydration with HullRadSAS.

Hydration of biological macromolecules is important for their stability and function. Historically, attempts have been made to describe the degree of macromolecular hydration using a single parameter over a narrow range of values. Here, we describe a method to calculate two types of hydration: surface shell water and entrained water. A consideration of these two types of hydration helps to explain the "hydration problem" in hydrodynamics. The combination of these two types of hydration allows accurate calculation of hydrodynamic volume and related macromolecular properties such as sedimentation and diffusion coefficients, intrinsic viscosities, and the concentration-dependent non-ideality identified with sedimentation velocity experiments.

The association between offspring birthweight and future risk of maternal diabetes: A population-based study.

AIMS: As an indicator of maternal cardiometabolic health, newborn birthweight may be an important predictor of maternal type 2 diabetes mellitus (diabetes). We evaluated the relation between offspring birthweight and onset of maternal diabetes after pregnancy. METHODS: This retrospective cohort study used linked population-based health databases from Ontario, Canada. We included women aged 16-50 years without pre-pregnancy diabetes, and who had a live birth between 2006 and 2014. We used Cox proportional hazard regression to evaluate the association between age- and sex-standardized offspring birthweight percentile categories and incident maternal diabetes, while adjusting for maternal age, parity, year, ethnicity, gestational diabetes (GDM) and hypertensive disorders of pregnancy (HDP). Results were further stratified by the presence of GDM in the index pregnancy. RESULTS: Of 893,777 eligible participants, 14,329 (1.6%) women were diagnosed with diabetes over a median (IQR) of 4.4 (1.5-7.4) years of follow-up. There was a continuous positive relation between newborn birthweight above the 75th percentile and maternal diabetes. Relative to a birthweight between the 50th and 74.9th percentiles, women whose newborn had a birthweight between the 97th and 100th percentiles had an adjusted hazards ratio (aHR) of diabetes of 2.30 (95% CI 2.16-2.46), including an aHR of 2.01 (95% CI 1.83-2.21) among those with GDM, and 2.59 (2.36-2.84) in those without GDM. CONCLUSIONS: A higher offspring birthweight signals an increased risk of maternal diabetes, offering another potentially useful way to identify women especially predisposed to diabetes.

A proteome-wide map of chaperone-assisted protein refolding in a cytosol-like milieu.

The journey by which proteins navigate their energy landscapes to their native structures is complex, involving (and sometimes requiring) many cellular factors and processes operating in partnership with a given polypeptide chain's intrinsic energy landscape. The cytosolic environment and its complement of chaperones play critical roles in granting many proteins safe passage to their native states; however, it is challenging to interrogate the folding process for large numbers of proteins in a complex background with most biophysical techniques. Hence, most chaperone-assisted protein refolding studies are conducted in defined buffers on single purified clients. Here, we develop a limited proteolysis-mass spectrometry approach paired with an isotope-labeling strategy to globally monitor the structures of refolding Escherichia coli proteins in the cytosolic medium and with the chaperones, GroEL/ES (Hsp60) and DnaK/DnaJ/GrpE (Hsp70/40). GroEL can refold the majority (85%) of the E. coli proteins for which we have data and is particularly important for restoring acidic proteins and proteins with high molecular weight, trends that come to light because our assay measures the structural outcome of the refolding process itself, rather than binding or aggregation. For the most part, DnaK and GroEL refold a similar set of proteins, supporting the view that despite their vastly different structures, these two chaperones unfold misfolded states, as one mechanism in common. Finally, we identify a cohort of proteins that are intransigent to being refolded with either chaperone. We suggest that these proteins may fold most efficiently cotranslationally, and then remain kinetically trapped in their native conformations.

The prevalence of documented cardiovascular-related pregnancy complications: cross-sectional study in an academic primary care centre.

BACKGROUND: Pregnancy and the postpartum period offer a unique opportunity to identify patients with risk factors leading to premature cardiovascular disease (CVD), which often go unrecognised. AIM: This study investigates self-reported prevalence of CVD-related pregnancy complications and its documentation in electronic medical records (EMRs) in an academic family health team (AFHT). DESIGN & SETTING: A retrospective cross-sectional survey conducted from 2016 to 2017 in an AFHT. METHOD: The survey assessed self-reported pregnancy complications and obstetric histories of adult females. EMRs of responders who provided consent were appraised for documented pregnancy complications, and management of traditional cardiovascular risk factors post-pregnancy. RESULTS: Out of 211 responders, 28% (n = 60) had at least one pregnancy complication reported in the survey and/or in the EMR, of which 67% (n = 40) had the complication documented in their EMR. The most prevalent complications were preterm birth (PTB; 12%, n = 25), hypertensive disorders of pregnancy (HDP; 10%, n = 22), and gestational diabetes mellitus (GDM; 7%, n = 14). Twenty-nine per cent (n = 4) of the patients with GDM had a 75 g oral glucose tolerance test result documented post-pregnancy. Of those with HDP, 36% (n = 8) had body mass index and 50% (n = 11) had a blood pressure measurement recorded after delivery. CONCLUSION: There has been a significant lack of documentation of pregnancy-related cardiovascular risk factors and subsequent management, introducing a missed opportunity for early cardiovascular intervention. Adequate documentation of pregnancy complications in the EMR and better transitions in care between obstetric and primary care teams could potentially enable clinicians to intervene early and better manage females at increased risk of CVD.

Membrane proteins enter the fold.

Membrane proteins have historically been recalcitrant to biophysical folding studies. However, recent adaptations of methods from the soluble protein folding field have found success in their applications to transmembrane proteins composed of both α-helical and ß-barrel conformations. Avoiding aggregation is critical for the success of these experiments. Altogether these studies are leading to discoveries of folding trajectories, foundational stabilizing forces and better-defined endpoints that enable more accurate interpretation of thermodynamic data. Increased information on membrane protein folding in the cell shows that the emerging biophysical principles are largely recapitulated even in the complex biological environment.

Diabetes after pregnancy: a study protocol for the derivation and validation of a risk prediction model for 5-year risk of diabetes following pregnancy.

BACKGROUND: Pregnancy offers a unique opportunity to identify women at higher future risk of type 2 diabetes mellitus (DM). In pregnancy, a woman has greater engagement with the healthcare system, and certain conditions are more apt to manifest, such as gestational DM (GDM) that are important markers for future DM risk. This study protocol describes the development and validation of a risk prediction model (RPM) for estimating a woman's 5-year risk of developing type 2 DM after pregnancy. METHODS: Data will be obtained from existing Ontario population-based administrative datasets. The derivation cohort will consist of all women who gave birth in Ontario, Canada between April 2006 and March 2014. Pre-specified predictors will include socio-demographic factors (age at delivery, ethnicity), maternal clinical factors (e.g., body mass index), pregnancy-related events (gestational DM, hypertensive disorders of pregnancy), and newborn factors (birthweight percentile). Incident type 2 DM will be identified by linkage to the Ontario Diabetes Database. Weibull accelerated failure time models will be developed to predict 5-year risk of type 2 DM. Measures of predictive accuracy (Nagelkerke's R2), discrimination (C-statistics), and calibration plots will be generated. Internal validation will be conducted using a bootstrapping approach in 500 samples with replacement, and an optimism-corrected C-statistic will be calculated. External validation of the RPM will be conducted by applying the model in a large population-based pregnancy cohort in Alberta, and estimating the above measures of model performance. The model will be re-calibrated by adjusting baseline hazards and coefficients where appropriate. DISCUSSION: The derived RPM may help identify women at high risk of developing DM in a 5-year period after pregnancy, thus facilitate lifestyle changes for women at higher risk, as well as more frequent screening for type 2 DM after pregnancy.

De novo design of transmembrane ß barrels.

Transmembrane ß-barrel proteins (TMBs) are of great interest for single-molecule analytical technologies because they can spontaneously fold and insert into membranes and form stable pores, but the range of pore properties that can be achieved by repurposing natural TMBs is limited. We leverage the power of de novo computational design coupled with a "hypothesis, design, and test" approach to determine TMB design principles, notably, the importance of negative design to slow ß-sheet assembly. We design new eight-stranded TMBs, with no homology to known TMBs, that insert and fold reversibly into synthetic lipid membranes and have nuclear magnetic resonance and x-ray crystal structures very similar to the computational models. These advances should enable the custom design of pores for a wide range of applications.

BMI and risk of gestational diabetes among women of South Asian and Chinese ethnicity: a population-based study.

AIMS/HYPOTHESIS: The aim of this study was to examine how BMI influences the association between Asian ethnicity and risk of gestational diabetes (GDM). METHODS: This population-based cohort study included pregnant women without pre-existing diabetes mellitus in Ontario, Canada between 2012 and 2014. Women of Chinese and South Asian ethnicity were identified using a validated surname algorithm. GDM was ascertained using hospitalisation codes. The relationship between ethnicity and GDM was modelled using modified Poisson regression, adjusted for maternal age, pre-pregnancy BMI, parity, previous GDM, long-term residency status, income quintile and smoking status. An interaction term between ethnicity and pre-pregnancy BMI was tested. RESULTS: Of 231,618 pregnant women, 9289 (4.0%) were of South Asian ethnicity and 12,240 (5.3%) were of Chinese ethnicity. Relative to women from the general population, in whom prevalence of GDM was 4.3%, the adjusted RR of GDM was higher among those of South Asian ethnicity (1.81 [95% CI 1.64, 1.99]) and Chinese ethnicity (1.66 [95% CI 1.53, 1.80]). The association between GDM and Asian ethnicity remained significant across BMI categories but differed according to BMI. The prevalence of GDM exceeded 5% at an estimated BMI of 21.5 kg/m2 among South Asian women, 23.0 kg/m2 among Chinese women and 29.5 kg/m2 among the general population. CONCLUSIONS/INTERPRETATION: The risk of GDM is significantly higher in South Asian and Chinese women, whose BMI is lower than that of women in the general population. Accordingly, targeted GDM prevention strategies may need to consider lower BMI cut-points for Asian populations.

Local Bilayer Hydrophobicity Modulates Membrane Protein Stability.

Through the insertion of nonpolar side chains into the bilayer, the hydrophobic effect has long been accepted as a driving force for membrane protein folding. However, how the changing chemical composition of the bilayer affects the magnitude of the side-chain transfer free energies (ΔGsc°) has historically not been well understood. A particularly challenging region for experimental interrogation is the bilayer interfacial region that is characterized by a steep polarity gradient. In this study, we have determined the ΔGsc° for nonpolar side chains as a function of bilayer position using a combination of experiment and simulation. We discovered an empirical correlation between the surface area of the nonpolar side chain, the transfer free energies, and the local water concentration in the membrane that allows for ΔGsc° to be accurately estimated at any location in the bilayer. Using these water-to-bilayer ΔGsc° values, we calculated the interface-to-bilayer transfer free energy (ΔGi,b°). We find that the ΔGi,b° are similar to the "biological", translocon-based transfer free energies, indicating that the translocon energetically mimics the bilayer interface. Together these findings can be applied to increase the accuracy of computational workflows used to identify and design membrane proteins as well as bring greater insight into our understanding of how disease-causing mutations affect membrane protein folding and function.