Chemically induced vesiculation as a platform for studying TMEM16F activity.

Calcium-activated phospholipid scramblase mediates the energy-independent bidirectional translocation of lipids across the bilayer, leading to transient or, in the case of apoptotic scrambling, sustained collapse of membrane asymmetry. Cells lacking TMEM16F-dependent lipid scrambling activity are deficient in generation of extracellular vesicles (EVs) that shed from the plasma membrane in a Ca2+-dependent manner, namely microvesicles. We have adapted chemical induction of giant plasma membrane vesicles (GPMVs), which require both TMEM16F-dependent phospholipid scrambling and calcium influx, as a kinetic assay to investigate the mechanism of TMEM16F activity. Using the GPMV assay, we identify and characterize both inactivating and activating mutants that elucidate the mechanism for TMEM16F activation and facilitate further investigation of TMEM16F-mediated lipid translocation and its role in extracellular vesiculation.

Social justice, activism and dentistry in the era of #BLM.

The #Black Lives Matter (BLM) movement thrust the dental profession into a period of critical reflection. Whilst there is enthusiasm for critical reflection and change now, we know from other social movements, like feminism, that this initial phase or 'wave' of activity will subside, hopefully to be replaced by a next 'wave'. How will we nurture this moment of activism and ensure that this initial energetic phase of activism and mobilisation transforms into more sustained and sustainable change? This article offers a sociological-ethical framework to ascertain if dentistry is the progressive and responsive profession it claims to be in the immediate aftermath of the #BLM movement. The dual theory of justice developed by Nancy Fraser (2001, 2004, 2005) and its distinction of the role played by redistribution and recognition in the pursuit of justice will be used to illuminate the challenges that dentistry and oral health face in this regard. It then plots the current efforts of the dental profession against the known trajectory of social movements to adjudicate what has been achieved and what work is yet to be done to ensure inclusion and race-based justice.

Dentistry, e-health and digitalisation: A critical narrative review of the dental literature on digital technologies with insights from health and technology studies.

OBJECTIVE: To overview current developments in e-health and digitalisation in dentistry and identify gaps in the dental literature on this topic; Basic research design: a critical narrative review of published articles and relevant online materials; Results: Four themes are identified as characterising the current dental literature on e-health and digitalisation: 1) the impact of digitalisation on dental surgeries, 2) digital technology and practice management, 3) digitalisation beyond the dental surgery and in dentist-patient communication, and 4) digital technology and education. However, gaps remain in our understanding of the impact of digital technology on dental practice, particularly in relation to its ethical considerations. Following the example of the wider medical literature, the review introduces the field of critical digital health studies and identifies areas for future investigation and exploration based on its four characteristics: devices and software, data materialisation, data practices and data mobilities; Conclusion and Clinical significance: Digital technology is changing clinical practice and patient care. Dentistry needs to expand its understanding of how dental apps, digital workflow models and digital health information are transforming and disrupting dental practice in order to anticipate how this digital shift will impact on dentistry. The emerging field of critical digital health studies can signpost ways to improve research and practice on the topic in the future.

Atomistic insight into lipid translocation by a TMEM16 scramblase.

The transmembrane protein 16 (TMEM16) family of membrane proteins includes both lipid scramblases and ion channels involved in olfaction, nociception, and blood coagulation. The crystal structure of the fungal Nectria haematococca TMEM16 (nhTMEM16) scramblase suggested a putative mechanism of lipid transport, whereby polar and charged lipid headgroups move through the low-dielectric environment of the membrane by traversing a hydrophilic groove on the membrane-spanning surface of the protein. Here, we use computational methods to explore the membrane-protein interactions involved in lipid scrambling. Fast, continuum membrane-bending calculations reveal a global pattern of charged and hydrophobic surface residues that bends the membrane in a large-amplitude sinusoidal wave, resulting in bilayer thinning across the hydrophilic groove. Atomic simulations uncover two lipid headgroup-interaction sites flanking the groove. The cytoplasmic site nucleates headgroup-dipole stacking interactions that form a chain of lipid molecules that penetrate into the groove. In two instances, a cytoplasmic lipid interdigitates into this chain, crosses the bilayer, and enters the extracellular leaflet, and the reverse process happens twice as well. Continuum membrane-bending analysis carried out on homology models of mammalian homologs shows that these family members also bend the membrane-even those that lack scramblase activity. Sequence alignments show that the lipid-interaction sites are conserved in many family members but less so in those with reduced scrambling ability. Our analysis provides insight into how large-scale membrane bending and protein chemistry facilitate lipid permeation in the TMEM16 family, and we hypothesize that membrane interactions also affect ion permeation.

Developing a Dental Scrubs Ceremony to define professional identity and teach professionalism to dental undergraduates; lessons learned.

INTRODUCTION: The UK General Dental Council stipulates that professionalism is a key aspect of the teaching and training of dental students. However, dental educators highlight that teaching dental student's professionalism can be challenging and students often rate this teaching activity negatively. This article documents a teaching initiative at one UK Dental School that aimed to strengthen the professionalism curriculum by introducing a Dental Scrubs Ceremony for second-year students. MATERIALS AND METHOD: The Dental Scrubs Ceremony is inspired by the White Coat Ceremonies that medical students have in universities in North America. It marks the students' first step in their professional and clinical development, with the signing of a pledge of conduct and public presentation of dental scrubs to each student. We report student feedback questionnaire data over a three-year period together with reflections on the merits and limitations of this alternative approach to teaching professionalism. RESULTS: Student evaluation data show that the perceived usefulness and worthwhileness of a Dental Scrubs Ceremony have grown since its inception in 2015. Most students enjoyed the symbolism of the ceremony, receiving their dental scrubs in a formal event. However, there was mixed evaluation for its effectiveness to teach professionalism. CONCLUSION: A Dental Scrubs Ceremony is a useful addition to the formal curriculum of professionalism in a dental school. It provides dental students with an opportunity to be inducted into the dental profession as novice dental students starting out on their professional career.

New Continuum Approaches for Determining Protein-Induced Membrane Deformations.

The influence of the membrane on transmembrane proteins is central to a number of biological phenomena, notably the gating of stretch activated ion channels. Conversely, membrane proteins can influence the bilayer, leading to the stabilization of particular membrane shapes, topological changes that occur during vesicle fission and fusion, and shape-dependent protein aggregation. Continuum elastic models of the membrane have been widely used to study protein-membrane interactions. These mathematical approaches produce physically interpretable membrane shapes, energy estimates for the cost of deformation, and a snapshot of the equilibrium configuration. Moreover, elastic models are much less computationally demanding than fully atomistic and coarse-grained simulation methodologies; however, it has been argued that continuum models cannot reproduce the distortions observed in fully atomistic molecular dynamics simulations. We suggest that this failure can be overcome by using chemically and geometrically accurate representations of the protein. Here, we present a fast and reliable hybrid continuum-atomistic model that couples the protein to the membrane. We show that the model is in excellent agreement with fully atomistic simulations of the ion channel gramicidin embedded in a POPC membrane. Our continuum calculations not only reproduce the membrane distortions produced by the channel but also accurately determine the channel's orientation. Finally, we use our method to investigate the role of membrane bending around the charged voltage sensors of the transient receptor potential cation channel TRPV1. We find that membrane deformation significantly stabilizes the energy of insertion of TRPV1 by exposing charged residues on the S4 segment to solution.

Continuum descriptions of membranes and their interaction with proteins: Towards chemically accurate models.

Biological membranes deform in response to resident proteins leading to a coupling between membrane shape and protein localization. Additionally, the membrane influences the function of membrane proteins. Here we review contributions to this field from continuum elastic membrane models focusing on the class of models that couple the protein to the membrane. While it has been argued that continuum models cannot reproduce the distortions observed in fully-atomistic molecular dynamics simulations, we suggest that this failure can be overcome by using chemically accurate representations of the protein. We outline our recent advances along these lines with our hybrid continuum-atomistic model, and we show the model is in excellent agreement with fully-atomistic simulations of the nhTMEM16 lipid scramblase. We believe that the speed and accuracy of continuum-atomistic methodologies will make it possible to simulate large scale, slow biological processes, such as membrane morphological changes, that are currently beyond the scope of other computational approaches. This article is part of a Special Issue entitled: Membrane Proteins edited by J.C. Gumbart and Sergei Noskov.

An observational analysis of recent female dental enrolment figures in the Republic of Ireland.

PURPOSE/OBJECTIVE: This research investigates the participation and completion rates of Irish female undergraduate dental students from 2003 to 2014. METHODS: The Higher Education Authority database was accessed and dental students enrolment and completion figures were extracted, compiled and analysed according to gender distribution. RESULT: From 2003 to 2014, there has been a steady increase in the number of female students enrolled in and completing Ireland's undergraduate dentistry programmes. CONCLUSIONS: The findings reveal that a distinct process of feminisation has occurred in Ireland since the early 2000s. The feminisation of dentistry in Ireland will impact on workforce projections for the Irish dental service. However, more research needs to be undertaken to explore why female students are motivated to pursue a career in dentistry. Due regard also needs to be given to ensuring these women progress in their dental career. Dental education can play an important role here.

Significant laryngeal destruction in a northern European cohort of Behçet's disease patients.

OBJECTIVES: Behçet's disease (BD) is a multisystem autoimmune disease of unknown origin typically affecting the triad of oral and genital mucosa and the eye. Limited data are available in the literature regarding the otolaryngology-related manifestations of BD, particularly in northern Europeans. This is a novel study detailing surprising and significant laryngeal structural changes in a northern European cohort of BD. METHODS: Patients meeting the International Study Group for Behçet's Disease (ISGBD) and the International Criteria for Behçet's Disease (ICBD) criteria for diagnosis were identified from an institutional database. Patients underwent examination with an otolaryngologist, including flexible laryngoscopy. Intra-oral, pharyngeal and laryngeal manifestations of BD were documented and characterised. Patients underwent hearing assessment with pure-tone audiometry. RESULTS: Fifteen patients with BD were identified (4 male, 11 female; median age 36 years). 60% (n=9) showed evidence of disease on examination and flexible laryngoscopy. 33% (n=5) showed laryngeal changes related to BD. 13% (n=2) demonstrated bilateral sensorineural hearing loss. The 5 cases demonstrating laryngeal manifestations of disease are described in detail with photographic records. CONCLUSIONS: Limited data has been published regarding the laryngeal manifestations of BD, particularly in a northern European population. Our cohort of BD patients demonstrate significant laryngeal structural changes. It would appear that these clinically relevant changes may be more common than was previously thought. Raised awareness of the risk of laryngeal pathology in BD patients, often in the absence of overt clinical symptomatology, may result in earlier diagnosis and treatment. Rheumatologists and otolaryngologists should consider closer multi-disciplinary co-operation in the management and follow up of patients with BD.

De novo design of pH-responsive self-assembling helical protein filaments.

Biological evolution has led to precise and dynamic nanostructures that reconfigure in response to pH and other environmental conditions. However, designing micrometre-scale protein nanostructures that are environmentally responsive remains a challenge. Here we describe the de novo design of pH-responsive protein filaments built from subunits containing six or nine buried histidine residues that assemble into micrometre-scale, well-ordered fibres at neutral pH. The cryogenic electron microscopy structure of an optimized design is nearly identical to the computational design model for both the subunit internal geometry and the subunit packing into the fibre. Electron, fluorescent and atomic force microscopy characterization reveal a sharp and reversible transition from assembled to disassembled fibres over 0.3 pH units, and rapid fibre disassembly in less than 1 s following a drop in pH. The midpoint of the transition can be tuned by modulating buried histidine-containing hydrogen bond networks. Computational protein design thus provides a route to creating unbound nanomaterials that rapidly respond to small pH changes.

Mutation of the ST7 tumor suppressor gene on 7q31.1 is rare in breast, ovarian and colorectal cancers.

The gene ST7 has recently been implicated as the broad-range tumor suppressor on human chromosome 7q31.1. We did not detect somatic mutations in ST7 in any of 149 primary ovarian, breast or colon carcinomas. These data suggest that epigenetic downregulation or haploinsufficiency, rather than somatic genetic alterations, may be the primary mechanism of abrogation of ST7 function in these tumor types.

Precisely patterned nanofibres made from extendable protein multiplexes.

Molecular systems with coincident cyclic and superhelical symmetry axes have considerable advantages for materials design as they can be readily lengthened or shortened by changing the length of the constituent monomers. Among proteins, alpha-helical coiled coils have such symmetric, extendable architectures, but are limited by the relatively fixed geometry and flexibility of the helical protomers. Here we describe a systematic approach to generating modular and rigid repeat protein oligomers with coincident C2 to C8 and superhelical symmetry axes that can be readily extended by repeat propagation. From these building blocks, we demonstrate that a wide range of unbounded fibres can be systematically designed by introducing hydrophilic surface patches that force staggering of the monomers; the geometry of such fibres can be precisely tuned by varying the number of repeat units in the monomer and the placement of the hydrophilic patches.

The role of surgery for anaplastic thyroid carcinoma in the era of targeted therapeutics: A scoping review.

Background: Questions exist regarding patient selection for surgery in anaplastic thyroid carcinoma (ATC), particularly with the advent of neoadjuvant-targeted therapeutics. The present scoping review sought to evaluate what extent of surgical resection should be performed in ATC. Methods: A scoping review was carried out in accordance with Joanna Briggs Institute and the preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews (PRISMA-ScR) protocols. Included studies were required to provide clear description of the surgery performed for ATC. Results: The final search identified 6901 articles. Ultimately only 15 articles including 1484 patients met inclusion criteria. A total of 765 patients (51.5%) underwent attempted curative intent surgery. The approach to resection of adjacent tissues varied between studies. Eight studies considered laryngeal ± pharyngeal resection (8/15, 53.3%), eight studies (53.3%) considered tracheal resection and again eight studies (53.3%) considered esophageal resection. More extensive resections increased morbidity without improving overall survival (OS) (<9 months in the 12 studies using a combination of surgery and chemoradiotherapy). In the three studies utilizing targeted therapy in addition to surgery, OS was notably improved while surgical resection following neoadjuvant therapy was less extensive. Conclusions: There is no clear agreement in the literature regarding the limits of surgical resection in locoregionally advanced ATC. A definition of surgically resectable disease will be required to guide surgical decision making in ATC, particularly with the potential to reduce tumor burden using neoadjuvant targeted treatment in suitable patients. Level of evidence: III.

Local structural flexibility drives oligomorphism in computationally designed protein assemblies.

Many naturally occurring protein assemblies have dynamic structures that allow them to perform specialized functions. For example, clathrin coats adopt a wide variety of architectures to adapt to vesicular cargos of various sizes. Although computational methods for designing novel self-assembling proteins have advanced substantially over the past decade, most existing methods focus on designing static structures with high accuracy. Here we characterize the structures of three distinct computationally designed protein assemblies that each form multiple unanticipated architectures, and identify flexibility in specific regions of the subunits of each assembly as the source of structural diversity. Cryo-EM single-particle reconstructions and native mass spectrometry showed that only two distinct architectures were observed in two of the three cases, while we obtained six cryo-EM reconstructions that likely represent a subset of the architectures present in solution in the third case. Structural modeling and molecular dynamics simulations indicated that the surprising observation of a defined range of architectures, instead of non-specific aggregation, can be explained by constrained flexibility within the building blocks. Our results suggest that deliberate use of structural flexibility as a design principle will allow exploration of previously inaccessible structural and functional space in designed protein assemblies.

Factors associated with red blood cells transfusion during first bloodless priming cardiac surgery in children.

INTRODUCTION: Red blood cell (RBC) transfusion is often required during cardiac surgery in children. However, RBC is a rare product, and its transfusion is associated with adverse events and a worse surgical outcome. Characterization of factors related to RBC transfusion during cardiac surgery in children would provide prevention strategies. METHODS: We conducted a retrospective single-center study, including all children who underwent their first cardiac surgery using bloodless priming cardiopulmonary bypass (CPB). RESULTS: The study included 173 children between 2011 and 2019,; 57 had intraoperative transfusion and 17 postoperative transfusion. Age (OR: 0.76, p<0.001), weight (OR: 0.93, p<0.001), body mass index ([BMI] OR: 0.83, p<0.001), hemoglobin level (OR: 0.68, p<0.05), hematocrit level (OR: 0.88, p<0.05), mean corpuscular volume ([MCV] (OR: 0.86, p<0.001), hemodilution (OR: 100, p<0.01), and CPB duration (OR: 1.01, p<0.05) were associated with an increased risk of intraoperative transfusion in univariate analysis. In multivariate analysis, only CPB duration (OR: 1.02, p<0.001) and MCV (OR: 0.89, p<0.05) were associated with transfusion. Concerning postoperative transfusions, the RACHS surgical difficulty score (OR: 6.83, p<0.01), duration of CPB (OR: 1.01, p<0,001), length of stay in the PICU (OR: 2.37, p<0.001), length of hospitalization (OR: 1.2, p<0.001), and reoperation (OR: 20.59, p<0.001) were significant using univariate analysis, and only the need for a reoperation (OR: 19.16, p<0.01) remained significant in multivariate analysis. CONCLUSION: Low MCV appears to be one of the main risk factors for intraoperative transfusion in RBC. It may reflect iron deficiency that should be checked and supplemented preoperatively in order to reduce the risk of transfusion.

Systematic skin and nasal decolonization lowers Staphylococcus infection in pediatric cardiac surgery.

BACKGROUND: Postoperative infections occur in approximately 10% of pediatric cardiac surgeries, involving Staphylococcus species in most cases. Nasal decontamination of Staphylococcus with mupirocin has been reported to reduce postoperative Staphylococcus infections after cardiac surgery in adults, but the effect of preoperative decontamination in children undergoing cardiac surgery has not been sufficiently studied to reach consensus. METHODS: We conducted a single-center retrospective study to evaluate the impact of systematic preoperative decolonization with intranasal mupirocin application and skin-washing with chlorhexidine soap on postoperative Staphylococcus infection in children undergoing cardiac surgery. Our population was divided into three groups according to decolonization protocol (group N: no decolonization; group T: targeted decolonization in Staphylococcus aureus [SA] carriers only; and group S: systematic decolonization). RESULTS: A total of 393 children were included between October 2011 and August 2015 (122 in group N, 148 in group T, and 123 in group S). The Staphylococcus infection rate significantly decreased in group S compared to group N (0.8% vs. 7.7%; p < 0.05) and tended to decrease in group S compared to group T (0.8% vs. 4.7%; p = 0.06). Systematic decontamination also significantly reduced the rate of infections starting from the skin (including surgical site infections and bloodstream infections) compared to targeted decolonization or lack of decolonization, but had no effect on the rate of pulmonary infections. CONCLUSION: The results of our study suggest that systematic preoperative skin and nasal decontamination, regardless of SA carriage status, could reduce the rate of postoperative Staphylococcus infections after cardiac surgery in children.

Natural and Designed Proteins Inspired by Extremotolerant Organisms Can Form Condensates and Attenuate Apoptosis in Human Cells.

Many organisms can survive extreme conditions and successfully recover to normal life. This extremotolerant behavior has been attributed in part to repetitive, amphipathic, and intrinsically disordered proteins that are upregulated in the protected state. Here, we assemble a library of approximately 300 naturally occurring and designed extremotolerance-associated proteins to assess their ability to protect human cells from chemically induced apoptosis. We show that several proteins from tardigrades, nematodes, and the Chinese giant salamander are apoptosis-protective. Notably, we identify a region of the human ApoE protein with similarity to extremotolerance-associated proteins that also protects against apoptosis. This region mirrors the phase separation behavior seen with such proteins, like the tardigrade protein CAHS2. Moreover, we identify a synthetic protein, DHR81, that shares this combination of elevated phase separation propensity and apoptosis protection. Finally, we demonstrate that driving protective proteins into the condensate state increases apoptosis protection, and highlights the ability of DHR81 condensates to sequester caspase-7. Taken together, this work draws a link between extremotolerance-associated proteins, condensate formation, and designing human cellular protection.

Potential effects of Rift Valley fever in the United States.

Rift Valley fever virus (RVFV) has been the cause of disease outbreaks throughout Africa and the Arabian Peninsula, and the infection often results in heavy economic costs through loss of livestock. If RVFV, which is common to select agent lists of the US Department of Health and Human Services and the US Department of Agriculture, entered the United States, either by accidental or purposeful means, the effects could be substantial. A group of subject matter experts met in December 2009 to discuss potential implications of an introduction of RVF to the United States and review current modeling capabilities. This workshop followed a similar meeting held in April 2007. This report summarizes the 2 workshop proceedings. Discussions primarily highlighted gaps in current economic and epidemiologic RVF models as well as gaps in the overall epidemiology of the virus.