Splitting the anterior mitral leaflet impairs left ventricular function in an ovine model

OBJECTIVES: During mitral valve replacement, the anterior mitral leaflet is usually resected or modified. Anterior leaflet splitting seems the least disruptive modification. Reattachment of the modified leaflet to the annulus reduces the annulopapillary distance. The goal of this study was to quantify the acute effects on left ventricular function of splitting the anterior mitral leaflet and shortening the annulopapillary distance. METHODS: In 6 adult sheep, a wire was placed around the anterior leaflet and exteriorized through the left ventricular wall to enable splitting the leaflet in the beating heart. Releasable snares to reduce annulopapillary distance were likewise positioned and exteriorized. A mechanical mitral prosthesis was inserted to prevent mitral incompetence during external manipulations of the native valve. Instantaneous changes in left ventricular function were recorded before and after shortening the annulopapillary distance, then before and after splitting the anterior leaflet. RESULTS: After splitting the anterior leaflet, preload recruitable stroke work, stroke work, stroke volume, cardiac output, left ventricular end systolic pressure and mean pressure were significantly decreased by 26%, 23%, 12%, 9%, 15% and 11%, respectively. Shortening the annulopapillary distance was associated with significant decreases in the end systolic pressure volume relationship, preload recruitable stroke work, stroke work and left ventricular end systolic pressure by 67%, 33%, 15% and 13%, respectively. Shortening the annulopapillary distance after splitting the leaflet had no significant effect. CONCLUSIONS: Splitting the anterior mitral leaflet acutely impaired left ventricular contractility and haemodynamics in an ovine model. Shortening the annulopapillary distance after leaflet splitting did not further impair left ventricular function

Remuneration of primary dental care in England: a qualitative framework analysis of perspectives of a new service delivery model incorporating incentives for improved access, quality and health outcomes

Objective: This study aimed to describe stakeholder perspectives of a new service delivery model in primary care dentistry incorporating incentives for access, quality and health outcomes. Design: Data were collected through observations, interviews and focus groups. Setting: This was conducted under six UK primary dental care practices, three working under the incentive-driven contract and three working under the traditional activity-based contract. Participants: Observations were made of 30 dental appointments. Eighteen lay people, 15 dental team staff and a member of a commissioning team took part in the interviews and focus groups. Results: Using a qualitative framework analysis informed by Andersen’s model of access, we found oral health assessments influenced patients’ perceptions of need, which led to changes in preventive behaviour. Dentists responded to the contract, with greater emphasis on prevention, use of the disease risk ratings in treatment planning, adherence to the pathways and the utilisation of skill-mix. Participants identified increases in the capacity of practices to deliver more care as a result. These changes were seen to improve evaluated and perceived health and patient satisfaction. These outcomes fed back to shape people’s predispositions to visit the dentist. Conclusion: The incentive-driven contract was perceived to increase access to dental care, determine dentists’ and patients’ perceptions of need, their behaviours, health outcomes and patient satisfaction. Dentists face challenges in refocusing care, perceptions of preventive dentistry, deployment of skill mix and use of the risk assessments and care pathways. Dentists may need support in these areas and to recognise the differences between caring for individual patients and the patient-base of a practice

Analogue Mean Systemic Filling Pressure: a New Volume Management Approach During Percutaneous Left Ventricular Assist Device Therapy

The absence of an accepted gold standard to estimate volume status is an obstacle for optimal management of left ventricular assist devices (LVADs). The applicability of the analogue mean systemic filling pressure (Pmsa) as a surrogate of the mean circulatory pressure to estimate volume status for patients with LVADs has not been investigated. Variability of flows generated by the Impella CP, a temporary LVAD, should have no physiological impact on fluid status. This translational interventional ovine study demonstrated that Pmsa did not change with variable circulatory flows induced by a continuous flow LVAD (the average dynamic increase in Pmsa of 0.20 ± 0.95 mmHg from zero to maximal Impella flow was not significant (p = 0.68)), confirming applicability of the human Pmsa equation for an ovine LVAD model. The study opens new directions for future translational and human investigations of fluid management using Pmsa for patients with temporary LVADs

Assessing the risk of SARS-CoV-2 transmission in international professional golf.

Objectives: There is no published data on the incidence or risk of SARS-CoV-2 transmission when playing golf, a sport played outdoors where social distancing is possible. The purpose of this prospective study was to report incidence and transmission regarding SARS-CoV-2, of professional golfers competing on the PGA European Tour across 23 events in 11 countries. Methods: Daily symptom and temperature checks and weekly reverse transcriptase PCR (RT-PCR) screening were performed to determine potential carriage of SARS-CoV-2. Onset and type of symptomology were analysed. Gene expression and cycle thresholds (Cts) were reviewed for all positive cases. Repeat PCR testing was performed on all positive players. RT-PCR analysis included human housekeeping genes and various RNA genes specific for SARS-CoV-2. Results: During the study period, there were 2900 RT-PCR tests performed on 195 professional golfers competing on the European Tour. Four players tested positive on-site during the study period (0.14% of tests; positive results were declared with Ct <40). Two positive tests were returned as part of routine protocols, while two reported a history of close contact with an individual who had tested positive for SARS-CoV-2 and were isolated and target tested. All were asymptomatic at time of testing, with three developing symptoms subsequently. None required hospital admission. There was no transmission from player to player. Conclusion: Golf is an outdoor sport where social distancing is possible, meaning risks can be low if guidance is followed by participants. Risk of transmission of SARS-CoV-2 can be mitigated by highly accurate RT-PCR testing of participants and by setting up a safe bubble that includes testing players and support staff, as well as all persons coming into contact with them during the course of the tournament, for example, drivers and hotel staff. This report can also provide reassurance for participants and policy makers regarding community golf, which can be encouraged for the health benefits it provides, in a relatively low-risk environment, with minimal risk of transmission by observing sensible viral hygiene protocols

Liquid Polymorphism and Double Criticality in a Lattice Gas Model

We analyze the possible phase diagrams of a simple model for an associating liquid proposed previously. Our two-dimensional lattice model combines oreintati onal ice-like interactions and \"{}Van der Waals\"{} interactions which may be repulsive, and in this case represent a penalty for distortion of hydrogen bonds in the presence of extra molecules. These interactions can be interpreted in terms of two competing distances, but not necessarily soft-core. We present mean -field calculations and an exhaustive simulation study for different parameters which represent relative strength of the bonding interaction to the energy penalty for its distortion. As this ratio decreases, a smooth disappearance of the doubl e criticality occurs. Possible connections to liquid-liquid transitions of molecul ar liquids are suggested

Pilot evaluation of risk assessment and enhanced protocols regarding contacts at an international professional golf event

Objectives The aim of this study was to assess whether a risk assessment and managed risk approach to contact tracing was practical and feasible at the Gran Canaria Lopesan Open 2021 and could inform further pilot work regarding disease transmission during elite sporting events. Methods This prospective cohort study included all international attendees. All participants required a minimum of one negative reverse transcriptase PCR (RT-PCR) test prior to travelling to each tournament. High-risk contacts were isolated for 10 days. Moderate-risk contacts received education regarding enhanced medical surveillance, had daily rapid antigen testing for 5 days, with RT-PCR day 5, mandated mask use and access to outside space for work purposes only. Low-risk contacts received rapid antigen testing every 48 hours and PCR testing on day 5. Results A total of 550 persons were accredited and were required to undergo RT-PCR testing before the event. Two of these tests were positive (0.36%). Of these, case 1 had 1 high, 23 moderate and 48 low-risk contacts. Case 2 did not have any significant travel history within 2 days of positive test and had one high-risk contact. There were no further positive tests on site in the wider cohort of attendees, from a total of 872 RT-PCR and 198 rapid antigen tests. Conclusions This pilot study showed it is practical, feasible and well accepted to provide enhanced (daily) virus testing and risk-mitigating measures at a professional golf event. Further study is required to assess the efficacy of these interventions; however, no transmission was found in this pilot study

Risk assessment and implementation of risk reduction measures is not associated with increased transmission of SARS-CoV-2 compared with standard isolation at professional golf events

Objectives The purpose of this prospective study was to report incidence and transmission of SARS-CoV-2, among professional golfers and essential support staff undergoing risk assessment and enhanced risk reduction measures when considered a close contact as opposed to standard isolation while competing on the DP World Tour during the 2021 season. Methods This prospective cohort study included all players and essential support staff participating in 26 DP World Tour events from 18 April 2021 to 21 November 2021. High-risk contacts were isolated for 10 days. Moderate-risk contacts received education regarding enhanced medical surveillance, had daily rapid antigen testing for 5 days, with reverse transcriptase-polymerase chain reaction (RT-PCR) tesing on day 5, mandated mask use and access to outside space for work purposes only. Low-risk contacts typically received rapid antigen testing every 48 hours and RT-PCR testing on day 5. Results The total study cohort compromised 13 394 person-weeks of exposure. There were a total of 30 positive cases over the study period. Eleven contacts were stratified as ‘high risk’. Two of these subsequently tested positive for SARS-CoV-2. There were 79 moderate-risk contact and 73 low-risk contacts. One moderate-risk contact subsequently tested positive for SARS-CoV-2 but did not transmit the virus. All other contacts, remained negative and asymptomatic to the end of the tournament week. Conclusions A risk assessment and risk reduction-based approach to contact tracing was safe in this professional golf event setting when Alpha and Delta were the predominant variants. It enabled professional golfers and essential support staff to work

Cord blood group 2 innate lymphoid cells are associated with lung function at 6 weeks of age.

Objective: Offspring born to mothers with asthma in pregnancy are known to have lower lung function which tracks with age. Human group 2 innate lymphoid cells (ILC2) accumulate in foetal lungs, at 10-fold higher levels compared to adult lungs. However, there are no data on foetal ILC2 numbers and the association with respiratory health outcomes such as lung function in early life. We aimed to investigate cord blood immune cell populations from babies born to mothers with asthma in pregnancy. Methods: Cord blood from babies born to asthmatic mothers was collected, and cells were stained in whole cord blood. Analyses were done using traditional gating approaches and computational methodologies (t-distributed stochastic neighbour embedding and PhenoGraph algorithms). At 6 weeks of age, the time to peak tidal expiratory flow as a percentage of total expiratory flow time (tPTEF/tE%) was determined as well as Lung Clearance Index (LCI), during quiet natural sleep. Results: Of 110 eligible infants (March 2017 to November 2019), 91 were successfully immunophenotyped (82.7%). Lung function was attempted in 61 infants (67.0%), and 43 of those infants (70.5% of attempted) had technically acceptable tPTEF/tE% measurements. Thirty-four infants (55.7% of attempted) had acceptable LCI measurements. Foetal ILC2 numbers with increased expression of chemoattractant receptor-homologous molecule (CRTh2), characterised by two distinct analysis methodologies, were associated with poorer infant lung function at 6 weeks of age." Conclusion: Foetal immune responses may be a surrogate variable for or directly influence lung function outcomes in early life

Returning persons with SARS-CoV-2 to the field of play in professional golf: a risk assessment and risk reduction approach

Objectives This pilot study aimed to see whether a risk assessment and risk reduction approach was a practical and feasible approach, as compared with standard isolation for fully vaccinated, asymptomatic persons positive for SARS-CoV-2. Methods This prospective cohort study included all players and caddies participating in two large professional golf events from 7 to 20 February 2022 in South Africa. Fully vaccinated persons testing positive who were asymptomatic were subject to risk assessment and risk reduction measures to protect the integrity of the event. Asymptomatic individuals who could socially distance in outdoor areas were allowed to participate. Close contacts were subject to daily rapid antigen tests and asked to prioritise outdoor space. Results The protocols put in place for the events were practical, feasible, and well accepted by event participants and staff during the study period. There was a total of 378 player-week episodes and 378 caddie-week episodes during the study period. Three persons tested positive while registered at events during the study period (0.4% of person episodes). The positive tests were returned from two players and one caddie, all of which were asymptomatic at the time of testing. There was one high-risk contact who consistently returned negative antigen tests. There was no evidence of transmission. Conclusions The approach was practical and feasible. A risk assessment and risk reduction approach allowed fully vaccinated asymptomatic persons with SARS-CoV-2 to participate in golf, an outdoor sport where social distancing is possible, compared with standard isolation