Restoring Atrial T-Tubules Augments Systolic Ca Upon Recovery From Heart Failure.

BACKGROUND: Transverse (t)-tubules drive the rapid and synchronous Ca2+ rise in cardiac myocytes. The virtual complete atrial t-tubule loss in heart failure (HF) decreases Ca2+ release. It is unknown if or how atrial t-tubules can be restored and how this affects systolic Ca2+. METHODS: HF was induced in sheep by rapid ventricular pacing and recovered following termination of rapid pacing. Serial block-face scanning electron microscopy and confocal imaging were used to study t-tubule ultrastructure. Function was assessed using patchclamp, Ca2+, and confocal imaging. Candidate proteins involved in atrial t-tubule recovery were identified by western blot and expressed in rat neonatal ventricular myocytes to determine if they altered t-tubule structure. RESULTS: Atrial t-tubules were lost in HF but reappeared following recovery from HF. Recovered t-tubules were disordered, adopting distinct morphologies with increased t-tubule length and branching. T-tubule disorder was associated with mitochondrial disorder. Recovered t-tubules were functional, triggering Ca2+ release in the cell interior. Systolic Ca2+, ICa-L, sarcoplasmic reticulum Ca2+ content, and SERCA function were restored following recovery from HF. Confocal microscopy showed fragmentation of ryanodine receptor staining and movement away from the z-line in HF, which was reversed following recovery from HF. Acute detubulation, to remove recovered t-tubules, confirmed their key role in restoration of the systolic Ca2+ transient, the rate of Ca2+ removal, and the peak L-type Ca2+ current. The abundance of telethonin and myotubularin decreased during HF and increased during recovery. Transfection with these proteins altered the density and structure of tubules in neonatal myocytes. Myotubularin had a greater effect, increasing tubule length and branching, replicating that seen in the recovery atria. CONCLUSIONS: We show that recovery from HF restores atrial t-tubules, and this promotes recovery of ICa-L, sarcoplasmic reticulum Ca2+ content, and systolic Ca2+. We demonstrate an important role for myotubularin in t-tubule restoration. Our findings reveal a new and viable therapeutic strategy.

The kinematics of amblypygid (Arachnida) pedipalps during predation: extreme elongation in raptorial appendages does not result in a proportionate increase in reach and closing speed.

The link between form and function is key to understanding the evolution of unique and/or extreme morphologies. Amblypygids, or whip spiders, are arachnids that often have highly elongated spined pedipalps. These limbs are used to strike at, and secure, prey before processing by the chelicerae. Amblypygi pedipalps are multifunctional, however, being used in courtship and contest, and vary greatly in form between species. Increased pedipalp length may improve performance during prey capture, but length could also be influenced by factors including territorial contest and sexual selection. Here, for the first time, we used high-speed videography and manual tracking to investigate kinematic differences in prey capture between amblypygid species. Across six morphologically diverse species, spanning four genera and two families, we created a total dataset of 86 trials (9-20 per species). Prey capture kinematics varied considerably between species, with differences being expressed in pedipalp joint angle ranges. In particular, maximum reach ratio did not remain constant with total pedipalp length, as geometric scaling would predict, but decreased with longer pedipalps. This suggests that taxa with the most elongated pedipalps do not deploy their potential length advantage to proportionally increase reach. Therefore, a simple mechanical explanation of increased reach does not sufficiently explain pedipalp elongation. We propose other factors to help explain this phenomenon, such as social interactions or sexual selection, which would produce an evolutionary trade-off in pedipalp length between prey capture performance and other behavioural and/or anatomical pressures.

Reactivities of acrylamide warheads toward cysteine targets: a QM/ML approach to covalent inhibitor design.

Covalent inhibition offers many advantages over non-covalent inhibition, but covalent warhead reactivity must be carefully balanced to maintain potency while avoiding unwanted side effects. While warhead reactivities are commonly measured with assays, a computational model to predict warhead reactivities could be useful for several aspects of the covalent inhibitor design process. Studies have shown correlations between covalent warhead reactivities and quantum mechanic (QM) properties that describe important aspects of the covalent reaction mechanism. However, the models from these studies are often linear regression equations and can have limitations associated with their usage. Applications of machine learning (ML) models to predict covalent warhead reactivities with QM descriptors are not extensively seen in the literature. This study uses QM descriptors, calculated at different levels of theory, to train ML models to predict reactivities of covalent acrylamide warheads. The QM/ML models are compared with linear regression models built upon the same QM descriptors and with ML models trained on structure-based features like Morgan fingerprints and RDKit descriptors. Experiments show that the QM/ML models outperform the linear regression models and the structure-based ML models, and literature test sets demonstrate the power of the QM/ML models to predict reactivities of unseen acrylamide warhead scaffolds. Ultimately, these QM/ML models are effective, computationally feasible tools that can expedite the design of new covalent inhibitors.

What should be next in lifelong posterior hypospadias: Conclusions from the 2023 ERN eUROGEN and EJP-RD networking meeting.

BACKGROUND: A congenital disease is for life. Posterior hypospadias, the severe form of hypospadias with a penoscrotal, scrotal, or perineal meatus, is a challenging condition with a major impact on lifelong quality of life. AIM: Our network meeting is aimed to identify what is currently missing in the lifelong treatment of posterior hypospadias, to improve care, quality of life, and awareness for these patients. METHODS: The network meeting "Lifelong Posterior Hypospadias" in Utrecht, The Netherlands was granted by the European Joint Programme on Rare Diseases-Networking Support Scheme. There was a combination of interactive sessions (hackathons) and lectures. This paper can be regarded as the last phase of the hackathon. RESULTS: Surgery for hypospadias remains challenging and complications may occur until adulthood. Posterior hypospadias affects sexual function, fertility, and hormonal status. Transitional care from childhood into adulthood is currently insufficiently established. Patients should be more involved in defining desired treatment approach and outcome measures. For optimal outcome evaluation standardization of data collection and registration at European level is necessary. Tissue engineering may provide a solution to the shortage of healthy tissue in posterior hypospadias. For optimal results, cooperation between basic researchers from different centers, as well as involving clinicians and patients is necessary. CONCLUSIONS: To improve outcomes for patients with posterior hypospadias, patient voices should be included and lifelong care by dedicated healthcare professionals guaranteed. Other requirements are joining forces at European level in uniform registration of outcome data and cooperation in basic research.

A movement for movement: an exploratory study of primary healthcare professionals' perspectives on implementing the Royal College of General Practitioners' active practice charter initiative.

BACKGROUND: Regular physical activity (PA) results in extensive physical, psychological, and social benefits. Despite primary care being a key point of influence for PA behaviours in the UK, research indicates poor application of PA interventions in this context. To address this, the Royal College of General Practitioners' (RCGP) developed and implemented the Active Practice Charter (APC). The aim of the study was to evaluate the perceived impact and acceptability of the APC initiative from the perspective of primary healthcare professionals (PHPs). METHODS: An online exploratory cross-sectional survey was designed to assess the perceived impact, experiences, and challenges of the APC initiative, from the perspective of PHPs. The survey was distributed by the RCGP via email to 184 registered APC practices across the UK. RESULTS: Responses were reviewed from staff (n = 33) from 21 APC practices. Initiatives used by APC practices included: educational programmes, partnerships with PA providers, referral systems, and infrastructure investment. Perceived benefits included: increased awareness about PA, staff cohesion, and improved well-being. However, staff felt the APC had limited effect due to implementation barriers, including: a lack of engagement, time, resources, and funding. CONCLUSION: This is the first evaluation of any nationwide UK-based initiative engaging GP practices in promoting PA. Acknowledging the limitations in response rate, although support exists for the RCGP APC, the evaluation highlights challenges to its implementation. Nonetheless, the wide reach of the RCGP, combined with the cited staff and patient benefits, demonstrates the significant potential of the APC initiative. Given the need to address physical inactivity nationally, further development the APC offers a possible solution, with further research required to overcome the challenges to implementation.

Distributional coding of associative learning in discrete populations of midbrain dopamine neurons.

Midbrain dopamine neurons are thought to play key roles in learning by conveying the difference between expected and actual outcomes. Recent evidence suggests diversity in dopamine signaling, yet it remains poorly understood how heterogeneous signals might be organized to facilitate the role of downstream circuits mediating distinct aspects of behavior. Here, we investigated the organizational logic of dopaminergic signaling by recording and labeling individual midbrain dopamine neurons during associative behavior. Our findings show that reward information and behavioral parameters are not only heterogeneously encoded but also differentially distributed across populations of dopamine neurons. Retrograde tracing and fiber photometry suggest that populations of dopamine neurons projecting to different striatal regions convey distinct signals. These data, supported by computational modeling, indicate that such distributional coding can maximize dynamic range and tailor dopamine signals to facilitate specialized roles of different striatal regions.

A value hierarchy for inclusive design of heart valve implants in regenerative medicine.

Aim: This paper investigates the conditions for inclusive design of regenerative medicine interventions from a bioethical perspective, taking regenerative valve implants as a showcase.Methods: A value hierarchy is construed to translate the value of justice into norms and design requirements for inclusive design of regenerative valve implants.Results: Three norms are proposed and translated into design requirements: regenerative valve implants should be designed to promote equal opportunity to good health for all potential users; equal respect for all potential users should be shown; and the implants should be designed to be accessible to everyone in need.Conclusion: The norms and design requirements help to design regenerative valve implants that are appropriate, respectful and available for everyone in need.

Scientists in the field of regenerative medicine are developing a new type of heart valve implant. After implantation, the synthetic implant slowly breaks down and is replaced by a new living heart valve. These so-called regenerative implants promise a complete cure. However, they also raise ethical questions. For example, questions related to justice and inclusion. In this paper, we explore how regenerative implants can be designed to be inclusive, meaning suitable, respectful and available for everyone. We argue that the design of regenerative implants should be adapted to relevant differences between users. The implants should be affordable in the short and long term. The implants should be suitable for use worldwide. The implants should be designed by teams of diverse age, gender and ethnicity. Users should be engaged in the design. And the communication about the implants to researchers and users should be inclusive. Overall, this paper provides ethical guidance to researchers and clinicians developing regenerative implants.

The genome sequence of the Rock Grayling, Hipparchia semele (Linnaeus, 1758).

We present a genome assembly from an individual female Hipparchia semele (the Rock Grayling; Arthropoda; Insecta; Lepidoptera; Nymphalidae). The genome sequence is 403.4 megabases in span. Most of the assembly is scaffolded into 30 chromosomal pseudomolecules, including the W and Z sex chromosomes. The mitochondrial genome has also been assembled and is 15.22 kilobases in length. Gene annotation of this assembly on Ensembl identified 17,540 protein coding genes.