Factors affecting electrogram sensing in an insertable cardiac monitor: Insights from surface electrocardiogram mapping analysis.

BACKGROUND: Fidelity of electrogram sensing may reduce false alerts from an insertable cardiac monitor (ICM). OBJECTIVE: The purpose of this study was to assess the effect of vector length, implant angle, and patient factors on electrogram sensing using surface electrocardiogram (ECG) mapping. METHODS: Twelve separate precordial single-lead surface ECGs were acquired from 150 participants at 2 interelectrode distances (75 and 45 mm), at 3 vector angles (vertical, oblique, and horizontal), and in 2 postures (upright and supine). A subset of 50 patients also received a clinically indicated ICM implant in 1:1 ratio (Reveal LINQ [Medtronic, Minneapolis, MN]/BIOMONITOR III [Biotronik, Berlin, Germany]). All ECGs and ICM electrograms were analyzed by blinded investigators using DigitizeIt software (V2.3.3, Braunschweig, Germany). The P-wave visibility threshold was set at > 0.015 mV. Logistic regression was used to identify factors affecting P-wave amplitude. RESULTS: A total of 1800 tracings from 150 participants (44.5% [n = 68] female; median age 59 [35-73] years) were assessed. The median P- and R-wave amplitudes were 45% and 53% larger with vector lengths of 75 and 45 mm, respectively (P < .001 for both). The oblique orientation yielded the best P- and R-wave amplitudes, while posture change did not affect P-wave amplitude. Mixed effects modeling found that visible P-waves occur more frequently with a vector length of 75 mm than with 45 mm (86% vs 75%, respectively; P < .0001). A longer vector length improved both P-wave amplitude and visibility in all body mass index categories. There was a moderate correlation of P- and R-wave amplitudes from the ICM electrograms to those from surface ECG recordings (intraclass correlation coefficient 0.74 and 0.80, respectively). CONCLUSION: Longer vector length and oblique implant angle yielded the best electrogram sensing and are relevant considerations for ICM implantation procedures.

The Burden of Cardiac Implantable Electronic Device Checks in the Peri-MRI Setting: The CHECK-MRI Study.

BACKGROUND: Most modern cardiac implantable electronic device (CIED) systems are now compatible with magnetic resonance imaging (MRI) scans. The requirement for both pre- and post-MRI CIED checks imposes significant workload to the cardiac electrophysiology service. Here, we sought to determine the burden of CIED checks associated with MRI scans. METHODS: We identified all CIED checks performed peri-MRI scans at our institution over a 3-year period between 1 July 2017 to 30 June 2020, comprising three separate financial years (FY). Device check reports, MRI scan reports and clinical summaries were collated. The workload burden was determined by assessing the occasions and duration of service. Analysis was performed to determine cost burden/projections for this service and identify factors contributing to the workload. RESULTS: A total of 739 CIED checks were performed in the peri-MRI scan setting (370 pre- and 369 post-MRI scan), including 5% (n=39) that were performed outside of routine hours (weekday <8 am or >5 pm, and weekends). MRIs were performed for 295 patients (75±13 years old, 64% male) with a CIED (88% permanent pacemaker, and 12% high voltage device), including 49 who had more than one MRI scan. The proportion of total MRI scans for patients with a CIED in-situ increased each FY (from 0.5% of all MRIs in FY1, to 0.9% in FY2, to 1.0% in FY3). The weekly workload increased (R2=0.2, p<0.001), but with week-to-week variability due to ad hoc scheduling (209 days with only one MRI vs 78 days with ≥2 MRIs for CIED patients). The projected annual cost of this service will increase to AUD$161,695 in 10 years for an estimated annual 546 MRI scans for CIED patients. CONCLUSIONS: There is an increasing workload burden and expense associated with CIED checks in the peri-MRI setting. Appropriate budgeting, staff allocation and standardisation of automated CIED pre-programming features among manufacturers are urgently needed.

Changes in R-wave amplitude at implantation are associated with gender and orientation of insertable cardiac monitor: observations from the confirm Rx™ body posture and physical activity study.

BACKGROUND: Insertable cardiac monitors (ICMs) are small subcutaneously implanted devices that detect changes in R-wave amplitudes (RWAs), effective in arrhythmia-monitoring. Although ICMs have proven to be immensely successful, electrical artefacts are frequent and can lead to misdiagnosis. Thus, there is a growing need to sustain and increase efficacy in detection rates by gaining insight into various patient-specific factors such as body postures and activities. METHODS: RWAs were measured in 15 separate postures, including supine, lying on the right-side (RS) or left-side (LS) and sitting, and two separate ICM orientations, immediately after implantation of Confirm Rx™ ICM in 99 patients. RESULTS: The patients (53 females and 46 males, mean ages 66.62 ± 14.7 and 66.40 ± 12.25 years, respectively) had attenuated RWAs in RS, LS and sitting by ~ 26.4%, ~ 27.8% and ~ 21.2% respectively, compared to supine. Gender-based analysis indicated RWAs in RS (0.32 mV (0.09-1.03 mV), p < 0.0001) and LS (0.37 mV (0.11-1.03 mV), p = 0.004) to be significantly attenuated compared to supine (0.52 mV (0.20-1.03 mV) for female participants. Similar attenuation was not evident for male participants. Further, parasternally oriented ICMs (n = 44), attenuated RWAs in RS (0.37 mV(0.09-1.03 mV), p = 0.05) and LS (0.34 mV (0.11-1.03 mV), p = 0.02) compared to supine (0.48 mV (0.09-1.03 mV). Similar differences were not observed in participants with ICMs in the 45°-relative-to-sternum (n = 46) orientation. When assessing the combined effect of gender and ICM orientation, female participants demonstrated plausible attenuation in RWAs for RS and LS postures compared to supine, an effect not observed in male participants. CONCLUSION: This is the first known study depicting the effects on RWA due to body postures and activities immediately post-implantation with an overt impact by gender and orientation of ICM. Future work assessing the cause of gender-based differences in RWAs may be critical. TRIAL REGISTRATION: Clinical Trials, NCT03803969. Registered 15 January 2019 - Retrospectively registered, https://clinicaltrials.gov/NCT03803969.

Fixation in the stochastic Lotka-Volterra model with small fitness trade-offs.

We study the probability of fixation in a stochastic two-species competition model. By identifying a naturally occurring fast timescale, we derive an approximation to the associated backward Kolmogorov equation that allows us to obtain an explicit closed form solution for the probability of fixation of either species. We use our result to study fitness tradeoff strategies and show that, despite some tradeoffs having nearly negligible effects on the corresponding deterministic dynamics, they can have large implications for the outcome of the stochastic system.

Cardiac Society of Australia and New Zealand (CSANZ) Position Statement on the Follow-Up of Cardiovascular Implantable Electronic Devices 2022.

Recognising the need for a national approach for the recommended best practice for the follow-up of implanted cardiac rhythm devices to ensure patient safety, this document has been produced by the Cardiac Society of Australia and New Zealand (CSANZ). It draws on accepted practice standards and guidelines of international electrophysiology bodies. It lays out methodology, frequency, and content of follow-up, including remote monitoring; personnel, including physician, allied health, nursing and industry; paediatric and adult congenital heart patients; and special considerations including magnetic resonance imaging scanning, perioperative management, and hazard alerts.

Impact of device length on electrogram sensing in miniaturized insertable cardiac monitors.

BACKGROUND: Little data exists on electrogram sensing in current generation of miniaturized insertable cardiac monitors (ICMs). OBJECTIVE: To compare the sensing capability of ICM with different vector length: Medtronic Reveal LINQ (~40 mm) vs. Biotronik Biomonitor III (BM-III, ~70 mm). METHODS: De-identified remote monitoring transmissions from n = 40 patients with BM-III were compared with n = 80 gender and body mass index (BMI)-matched patients with Reveal LINQ. Digital measurement of P- and R-wave amplitude from calibrated ICM electrograms was undertaken by 3 investigators independently. Further, we evaluated the impact of BMI and gender on P-wave visibility. RESULTS: Patients in both groups were well matched for gender and BMI (53% male, mean BMI 26.7 kg/m2, both p = NS). Median P- and R-wave amplitude were 97% & 56% larger in the BM-III vs. LINQ [0.065 (IQR 0.039-0.10) vs. 0.033 (IQR 0.022-0.050) mV, p < .0001; & 0.78 (IQR 0.52-1.10) vs. 0.50 (IQR 0.41-0.89) mV, p = .012 respectively). The P/R-wave ratio was 36% greater with the BM-III (p < .001). The 25th percentile of P-wave amplitude for all 120 patients was .026 mV. Logistic regression analysis showed BM-III was more likely than LINQ to have P-wave amplitude ≥.026 mV (OR 7.47, 95%CI 1.965-29.42, p = .003), and increasing BMI was negatively associated with P-wave amplitude ≥.026 mV (OR 0.84, 95%CI 0.75-0.95, p = .004). However, gender was not significantly associated with P-wave amplitude ≥.026 mV (p = .37). CONCLUSION: The longer ICM sensing vector of BM-III yielded larger overall P- and R- wave amplitude than LINQ. Both longer sensing vector and lower BMI were independently associated with greater P-wave visibility.

In vitro embryotoxicity and mode of antibacterial mechanistic study of gold and copper nanoparticles synthesized from Angelica keiskei (Miq.) Koidz. leaves extract.

The present study demonstrated the in vitro embryotoxicity assessment of gold nanoparticles (AuNPs) and copper nanoparticles (CuNPs) prepared from the leaves extract of Angelica keiskei (Miq.) Koidz. and addressed their mode of antibacterial mechanisms. Both AuNPs and CuNPs were rapidly synthesized and the formations were observed within 1 h and 24 h, respectively. Further the morphological images of the nanoparticles were confirmed through transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). The high-resolution X-ray diffraction (HR-XRD) analysis of the biosynthesized AuNPs and CuNPs were matched with joint committee on powder diffraction standards (JCPDS) file no of 04-0784 and 89-5899, respectively. A strong prominent Au and Cu signals were observed through energy dispersive spectroscopy (EDS) analysis. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed the responsible phytochemicals for the synthesis of AuNPs and CuNPs. In order to assess the toxic effects of AuNPs and CuNPs, bactericidal activity was performed against few of the test pathogens in which the effective inhibition was observed against Gram-negative bacteria than the Gram-positive bacteria. The mode of action and interaction of nanoparticles were performed on the bacterial pathogens and the results concluded that the interaction of nanoparticles initially initiated on the surface of the cell wall adherence followed by ruptured the cells and caused the cell death. In addition to the antibacterial activity, in vitro embryotoxicity studies were performed against zebrafish embryos and the results confirmed that 200 µg/ml concentration of AuNPs showed the embryotoxicity, whereas 2 µg/ml of CuNPs resulted the embryotoxicity. Furthermore, the morphological anomalies of zebrafish embryos revealed the toxic nature of the synthesized nanoparticles.

R-wave amplitude changes with posture and physical activity over time in an insertable cardiac monitor.

Background: Insertable cardiac monitors (ICMs) are accepted tools in cardiac arrhythmia management. Consistent R-wave amplitude (RWA) is essential for optimal detection. Objectives: Assess RWAs with posture/activities at insertion and at 30 days. Methods: Participants (n = 90) with Confirm Rx™ ICM had RWAs measured in different postures (supine, right-side [RS], left-side [LS], sitting, and standing) and defined physical activities (including isometric push [IPUSH] and pull) at 2 time points. ICMs were inserted in 45° to sternum and parasternal orientations. Results: There were significant reductions at insertion with RS, LS, sitting, or standing vs supine (reference position) (all P < .05). At 30 days, significant changes only occurred with LS and sitting (P < .05). Sex had an effect on RWAs, with females having significant variability at insertion (supine vs RS, LS, sitting, standing, and IPUSH; all P < .05). Males showed large RWA interpatient variabilities but minimal differences between positions vs supine. At 30 days, RS, LS, and sitting positions remained significant for females (P < .05), while in males RWAs were higher than at insertion for most postures and activities. The orientation 45° to sternum had consistently higher RWAs vs parasternal orientation at both time points (P < .0001). In females, ICM orientation had no significant effect on RWAs; however, in males the 45° to sternum produced higher RWAs. ICM movement from the insertion site showed no correlation with RWA changes. Conclusion: The mean RWAs were higher at 30 days with less interparticipant and interpostural variability; males had higher RWAs compared to females; 45° to sternum orientation had higher RWAs; and ICM migration from the insertion site did not affect RWAs.

Should We Check It? Assessing Interrogation of Cardiac Implantable Electronic Devices in the Emergency Department-The CHECK-ED Study: Implications for Service Planning and Care Delivery.

BACKGROUND: Requests from the emergency department (ED) for cardiac implantable electronic device (CIED) checks constitute a large workload for cardiac electrophysiology services. We sought to determine the yield of, and clinical characteristics associated with, clinically relevant (remarkable) issues from ED CIED checks. METHODS: Consecutive CIED checks from our ED over a 12-month period were studied. A remarkable issue (RI) was defined as arrhythmia relating to the presentation or device/lead issue requiring reprogramming or intervention. The association between the presenting complaint and an RI was assessed using regression analysis. Multivariable regression model was used to identify pre-specified patient-level characteristics that were predictive of a RI. RESULTS: A RI was found in 28% (n=98) of 354 ED CIED checks for 306 patients (76±16 yrs, 59% male). Most patients had no RI (n=224, 73%). One third of checks occurred after-hours and these had a higher yield of RIs than those during routine clinic hours (35% vs 23%, p=0.018). Presenting with a perceived ICD shock was predictive of a RI (odds ratio [OR] 6.0, 95% CI=1.8-20.0). Syncope/presyncope was five-fold less likely to be predictive of a RI (OR 0.19, 95% CI=0.13-0.28) despite being the most common indication for CIED check (51%, n=180 checks). Only history of AF was predictive of RI while advancing age was predictive of not finding a RI. CONCLUSION: Almost three-quarters of ED CIED checks did not yield any RI. Patient-reported ICD shock and history of AF were predictive of RI, while syncope/presyncope was not. New models of care especially during after-hours, may help to reduce the burden on cardiac electrophysiology services and health care costs.

Systematic review of electrophysiology procedures in patients with obstruction of the inferior vena cava.

AIMS: The objective of the study was to conduct a systematic review to describe and compare the different approaches for performing cardiac electrophysiology (EP) procedures in patients with interrupted inferior vena cava (IVC) or equivalent entities causing IVC obstruction. METHODS: We conducted a structured search to identify manuscripts reporting EP procedures with interrupted IVC or IVC obstruction of any aetiology published up until August 2020. No restrictions were applied in the search strategy. We also included seven local cases that met inclusion criteria. RESULTS: The analysis included 142 patients (mean age 48.9 years; 48% female) undergoing 143 procedures. Obstruction of the IVC was not known before the index procedure in 54% of patients. Congenital interruption of IVC was the most frequent cause (80%); and, associated congenital heart disease (CHD) was observed in 43% of patients in this setting. The superior approach for ablation was the most frequently used strategy (52%), followed by inferior approach via the azygos or hemiazygos vein (24%), transhepatic approach (14%), and retroaortic approach (10%). Electroanatomical mapping (58%), use of long sheaths (41%), intracardiac echocardiography (19%), transesophageal echocardiography (15%) and remote controlled magnetic navigation (13%) were used as adjuncts to aid performance. Ablation was successful in 135 of 140 procedures in which outcomes were reported. Major complications were only reported in patients undergoing AF ablation, including two patients with pericardial effusion, one of whom required surgical repair, and another patient who died after inadvertent entry into an undiagnosed atrioesophageal fistula from a previous procedure. CONCLUSION: The superior approach is most frequent approach for performing EP procedures in the setting of obstructed IVC. Transhepatic approach is a feasible alternative, and may provide a "familiar approach" for transseptal access when it is required. Adjunctive use of long sheaths, intravascular echocardiography, electro-anatomical mapping and remote magnetic navigation may be helpful, especially if there is associated complex CHD. With careful planning, EP procedures can usually be successfully performed with a low risk of complications.

Quantitative Imaging of Bacteriophage Amplification for Rapid Detection of Bacteria in Model Foods.

Rapid detection of bacteria in water and food samples is a critical need. The current molecular methods like real-time PCR can provide rapid detection after initial enrichment. However, these methods require significant preparation steps, specialized facilities to reduce contamination, and relatively expensive reagents. This study evaluates a novel approach for detecting bacteria based on imaging of bacteriophage amplification upon infection of the target host bacteria to mitigate some of these constraints and improve the specificity of discriminating live vs. dead bacteria. Thus, this research leverages the natural ability of lytic bacteriophages to rapidly amplify their genetic material and generate progeny phages upon infecting the host bacterium. This study uses a nucleic acid staining dye, a conventional fluorescence microscope, and quantitative image analysis for imaging the amplification of bacteriophages. The sensitivity and assay time for imaging-based quantification of phage amplification for detecting Escherichia coli were compared with RT-PCR and the standard plaque-forming assay for detection phage amplification in model systems, including coconut water and spinach wash water. The results demonstrate that the imaging approach matches both the sensitivity and speed for detecting E. coli using the RT-PCR method without requiring isolation of nucleic acids, expensive reagents, and specialized facilities. The quantitative imaging results demonstrate the detection of 10 CFU/ml of E. coli in coconut water and simulated spinach wash water with a chemical oxygen demand (COD) of 3,000 ppm within 8 h, including initial enrichment of the bacteria. In summary, the results of this study illustrate a novel phage amplification-based approach for detecting target bacteria in complex food and water samples using simple sample preparation methods and low-cost reagents.

Autonomic Afferent Dysregulation in Atrial Fibrillation.

OBJECTIVES: This study sought to evaluate the role of cardiac afferent reflexes in atrial fibrillation (AF). BACKGROUND: Efferent autonomic tone is not associated with atrial remodeling and AF persistence. However, the role of cardiac afferents is unknown. METHODS: Individuals with nonpermanent AF (n = 48) were prospectively studied (23 in the in-AF group and 25 in sinus rhythm [SR]) with 12 matched control subjects. We performed: 1) low-level lower body negative pressure (LBNP), which decreases cardiac volume, offloading predominantly cardiac afferent (volume-sensitive) low-pressure baroreceptors; 2) Valsalva reflex (predominantly arterial high-pressure baroreceptors); and 3) isometric handgrip reflex (both baroreceptors). We measured beat-to-beat mean arterial pressure (MAP) and heart rate (HR). LBNP elicits reflex vasoconstriction, estimated using venous occlusion plethysmography-derived forearm blood flow (∝1/vascular resistance), maintaining MAP. To assess reversibility, we repeated LBNP (same day) after 1-hour low-level tragus stimulation (in n = 5 in the in-AF group and n = 10 in the in-SR group) and >6 weeks post-cardioversion (n = 7). RESULTS: The 3 groups were well matched for age (59 ± 12 years, 83% male), body mass index, and risk factors (P = NS). The in-AF group had higher left atrial volume (P < 0.001) and resting HR (P = 0.01) but similar MAP (P = 0.7). The normal LBNP vasoconstriction (-49 ± 5%) maintaining MAP (control subjects) was attenuated in the in-SR group (-12 ± 9%; P = 0.005) and dysfunctional in the in-AF group (+11 ± 6%; P < 0.001), in which MAP decreased and HR was unchanged. Valsalva was normal throughout. Handgrip MAP response was lowest in the in-AF group (P = 0.01). Interestingly, low-level tragus stimulation and cardioversion improved LBNP vasoconstriction (-48 ± 15%; P = 0.04; and -32 ± 9%; P = 0.02, respectively). CONCLUSIONS: Cardiac afferent (volume-sensitive) reflexes are abnormal in AF patients during SR and dysfunctional during AF. This could contribute to AF progression, thus explaining "AF begets AF." (Characterisation of Autonomic function in Atrial Fibrillation [AF-AF Study]; ACTRN12619000186156).

Application of Engineered Bacteriophage T7 in the Detection of Bacteria in Food Matrices.

Detection of pathogens in a food matrix is challenging due to various constraints including complexity and the cost of sample preparation for microbial analysis from food samples, time period for the detection of pathogens, and high cost and specialized resources required for advanced molecular assays. To address some of these key challenges, this study illustrates a simple and rapid colorimetric detection of target bacteria in distinct food matrices, including fresh produce, without prior isolation of bacteria from a food matrix. This approach combines bacteriophage-induced expression of an exogenous enzyme, alkaline phosphatase, the specific colorimetric substrate that generates insoluble color products, and a simple filtration method to localize the generation of colored signal. Using this approach, this study demonstrates the specific detection of inoculated Escherichia coli in coconut water and baby spinach leaves. Without isolating bacteria from the selected food matrices and using a food sample size that is representative of industrial samples, the inoculated samples were added to the enrichment broth for a short period (5 h) and incubated with an engineered bacteriophage T7 with a phoA gene. The incubation period with the engineered bacteriophage was 30 min for liquid samples and 2 h for fresh produce samples. The samples were then filtered through a 0.2-micron polycarbonate membrane and incubated with a colorimetric substrate, i.e., nitro blue tetrazolium/5-bromo-4-chloro-3-indolyl phosphate (NBT/BCIP). This substrate forms a dark purple precipitate upon interactions with the released enzyme on a filter membrane. This approach successfully detected 10 CFU/ml of E. coli in coconut water and 102 CFU/g of E. coli on baby spinach leaves with 5 h of enrichment. Success of this approach illustrates potential for detecting target bacteria in food systems using a simple visual assay and/or quantitative colorimetric measurements.

Sex differences in Cardiac electronic device implantation: Outcomes from an Australian multi-centre clinical quality registry.

BACKGROUND: There is uncertainty regarding whether outcomes after Cardiac Implantable Electronic Devices (CIED) differ between women and men. There are no prospectively collected data regarding Australian CIED outcomes. This study aimed to determine whether the characteristics and outcomes of Australian patients undergoing CIED implantation differ by sex. METHODS: We prospectively followed 5,360 patients undergoing CIED implantation between 2015 and 2019 in a large multi-centre Australian registry. Patient characteristics, procedural data, medications and clinical outcomes to 1 year were analysed. RESULTS: The mean age was 76.2 + 11.2 years, and 2022 (37.7%) were female. Women were older than men at device implantation (77.0 ±â€¯11.6 years vs. 75.5 ±â€¯10.9 years, p < 0.001). Most implants were de novo (79.7%). Pacing was more commonly for sick sinus syndrome in women than men (54.4% vs. 47.2%, p < 0.001) and less often for A-V block (28.3% vs. 35.1%, p < 0.001). Adverse events at 30 days were low compared to international cohorts, for mortality (0.06%) and major complications (0.6%). There were no significant sex differences (women vs. men) for death (HR 1.33, 95% CI 0.58-3.13, p = 0.49) or major complications (HR 1.41, 95% 95% CI 0.65-3.03, p = 0.39). At 1-year, there was no difference in major complications or risk-adjusted all-cause mortality (HR 1.05, 95% CI 0.70-1.29, p = 0.77) between women and men. CONCLUSIONS: Clinical practice and 30-day outcomes after CIED implantation in Australia are consistent with international reports. There were no differences in procedural complication rates or clinical outcomes at 1-year between women and men, regardless of age or CIED system implanted.

Rapid identification of pathogens by using surface-enhanced Raman spectroscopy and multi-scale convolutional neural network.

Salmonella is a prevalent pathogen causing serious morbidity and mortality worldwide. There are over 2600 serovars of Salmonella. Among them, Salmonella Enteritidis, Salmonella Typhimurium, and Salmonella Paratyphi were reported to be the most common foodborne pathogenic serovars in the EU and China. In order to provide a more efficient approach to detect and distinguish these serovars, a new analytical method was developed by combining surface-enhanced Raman spectroscopy (SERS) with multi-scale convolutional neural network (CNN). We prepared 34-nm gold nanoparticles (AuNPs) as the label-free Raman substrate, measured 1854 SERS spectra of these three Salmonella serovars, and then proposed a multi-scale CNN model with three parallel CNNs to achieve multi-dimensional extraction of SERS spectral features. We observed the impact of the number of iterations and training samples on the recognition accuracy by changing the ratio of the number of the training and testing sets. By comparing the calculated data with experimental one, it was shown that our model could reach recognition accuracy more than 97%. These results indicate that it was not only feasible to combine SERS spectroscopy with multi-scale CNN for Salmonella serotype identification, but also for other pathogen species and serovar identifications.

Supporting people leaving prisons during COVID-19: perspectives from peer health mentors.

PURPOSE: Currently, people leaving prisons face concurrent risks from the COVID-19 pandemic and the overdose public health emergency. The closure or reduction of community services people rely on after release such as treatment centres and shelters has exacerbated the risks of poor health outcomes and harms. This paper aims to learn from peer health mentors (PHM) about changes to their work during overlapping health emergencies, as well as barriers and opportunities to support people leaving prison in this context. DESIGN/METHODOLOGY/APPROACH: The Unlocking the Gates (UTG) Peer Health Mentoring Program supports people leaving prison in British Columbia during the first three days after release. The authors conducted two focus groups with PHM over video conference in May 2020. Focus groups were recorded and transcribed, and themes were iteratively developed using narrative thematic analysis. FINDINGS: The findings highlighted the importance of peer health mentorship for people leaving prisons. PHM discussed increased opportunities for collaboration, ways the pandemic has changed how they are able to provide support, and how PHM are able to remain responsive and flexible to meet client needs. Additionally, PHM illuminated ways that COVID-19 has exacerbated existing barriers and identified specific actions needed to support client health, including increased housing and recovery beds, and tools for social and emotional well-being. ORIGINALITY/VALUE: This study contributes to our understanding of peer health mentorship during the COVID-19 pandemic from the perspective of mentors. PHM expertise can support release planning, improved health and well-being of people leaving prison and facilitate policy-supported pandemic responses.

The Rcs System in Enterobacteriaceae: Envelope Stress Responses and Virulence Regulation.

The bacterial cell envelope is a protective barrier at the frontline of bacterial interaction with the environment, and its integrity is regulated by various stress response systems. The Rcs (regulator of capsule synthesis) system, a non-orthodox two-component regulatory system (TCS) found in many members of the Enterobacteriaceae family, is one of the envelope stress response pathways. The Rcs system can sense envelope damage or defects and regulate the transcriptome to counteract stress, which is particularly important for the survival and virulence of pathogenic bacteria. In this review, we summarize the roles of the Rcs system in envelope stress responses (ESRs) and virulence regulation. We discuss the environmental and intrinsic sources of envelope stress that cause activation of the Rcs system with an emphasis on the role of RcsF in detection of envelope stress and signal transduction. Finally, the different regulation mechanisms governing the Rcs system's control of virulence in several common pathogens are introduced. This review highlights the important role of the Rcs system in the environmental adaptation of bacteria and provides a theoretical basis for the development of new strategies for control, prevention, and treatment of bacterial infections.

Trends in the use, complications, and costs of permanent pacemakers in Australia: A nationwide study from 2008 to 2017.

OBJECTIVE: To characterize contemporary pacemaker procedure trends. METHODS: Nationwide analysis of pacemaker procedures and costs between 2008 and 2017 in Australia. The main outcome measures were total, age- and gender-specific implant, replacement, and complication rates, and costs. RESULTS: Pacemaker implants increased from 12,153 to 17,862. Implantation rates rose from 55.3 to 72.6 per 100,000, a 2.8% annual increase (incidence rate ratio [IRR] 1.028; 95% CI, 1.02-1.04; p < .001). Pacemaker implants in the 80+ age group were 17.37-times higher than the < 50 group (95% CI 16.24-18.59; p < .001), and in males were 1.48-times higher than in females (95% CI 1.42-1.55; p < .001). However, there were similar increases according to age (p = .10) and gender (p = .68) over the study period. Left ventricular lead rates were stable (IRR 0.995; 95% CI 0.98-1.01; p = .53). Generator replacements decreased from 20.5 to 18.3 per 100,000 (IRR 0.975; 95% CI 0.97-0.98; p < .001). Although procedures for generator-related complications were stable (IRR 0.995; 95% CI 0.98-1.01; p = .54), those for lead-related complications decreased (IRR 0.985; 95% CI 0.98-0.99; p < .001). Rates for all pacemaker procedures were consistently greater in males (p < .001). Although annual costs of all pacemaker procedures increased from $178 million to $329 million, inflation-adjusted costs were more stable, rising from $294 million to $329 million. CONCLUSIONS: Increasing demand for pacemaker implants is driven by the ageing population and rising rates across all ages, while replacement and complication procedure rates appeared more stable. Males have consistently greater pacemaker procedure rates than females. Our findings have significant clinical and public health implications for healthcare resource planning.

Rapid detection of Escherichia coli using bacteriophage-induced lysis and image analysis.

Rapid detection of bacterial pathogens is a critical unmet need for both food and environmental samples such as irrigation water. As a part of the Food safety Modernization Act (FSMA), The Produce Safety rule has established several requirements for testing for the presence of generic Escherichia coli in water, but the current method available for testing (EPA M1603) demands specified multiple colony verification and highly trained personnel to perform these tests. The purpose of the study was to assess a phage induced bacterial lysis using quantitative image analysis to achieve rapid detection of E. coli at low concentrations within 8 hours. This study aimed to develop a simple yet highly sensitive and specific approach to detect target bacteria in complex matrices. In the study, E. coli cells were first enriched in tryptic soy broth (TSB), followed by T7 phage induced lysis, concentration, staining and fluorescent imaging. Image analysis was conducted including image pre-processing, image segmentation and quantitatively analysis of cellular morphological features (area, eccentricity and full width at half maximum). Challenge experiments using realistic matrices, including simulated fresh produce wash water, coconut water and spinach wash water, demonstrated the method can be applied for use in situations that occur in food processing facilities. The results indicated E. coli cells that are lysed by T7 phages demonstrated significantly (P < 0.05) higher extracellular DNA release, altered cellular shape (from rod to circular) and diffused fluorescent signal intensity. Using this biosensing strategy, a sensitivity to detect Escherichia coli at 10 CFU/ml within 8 hours was achieved, both in laboratory medium and in complex matrices. The proposed phage based biosensing strategy enables rapid detection of bacteria and is applicable to analysis of food systems. Furthermore, the steps involved in this assay can be automated to enable detection of target bacteria in food facilities without extensive resources.