CD40 forward signalling is a physiological regulator of early sensory axon growth.

Multiple members of the tumour necrosis factor superfamily (TNFSF) regulate the growth and branching of neural processes late in development, when neurons are establishing and refining connections. Here, we present the first evidence that a TNFSF member acts much earlier in development, when axons are growing to their targets. CD40L transiently enhanced axon growth from embryonic mouse DRG neurons cultured at this early stage. Early spinal nerves of embryos lacking the CD40L receptor (Cd40-/- mice) were significantly shorter in vivo than those of Cd40+/+ littermates. CD40L was synthesized in early DRG targets and was co-expressed with CD40 in early DRG neurons. Whereas CD40L enhanced early axon growth independently of neurotrophins, disruption of a CD40L/CD40 autocrine loop impaired early neurotrophin-promoted axon growth. In marked contrast to the widespread regulation of axon and dendrite growth by CD40L reverse signalling later in development, CD40-Fc, which activates reverse signalling, had no effect on early sensory axon growth. These results suggest that CD40 forward signalling is a novel physiological regulator of early axon growth that acts by target-derived and autocrine mechanisms.

Modeling Immune Evasion and Vaccine Limitations by Targeted Nasopharyngeal Bordetella pertussis Inoculation in Mice.

Conventional pertussis animal models deliver hundreds of thousands of Bordetella pertussis bacteria deep into the lungs, rapidly inducing severe pneumonic pathology and a robust immune response. However, human infections usually begin with colonization and growth in the upper respiratory tract. We inoculated only the nasopharynx of mice to explore the course of infection in a more natural exposure model. Nasopharyngeal colonization resulted in robust growth in the upper respiratory tract but elicited little immune response, enabling prolonged and persistent infection. Immunization with human acellular pertussis vaccine, which prevents severe lung infections in the conventional pneumonic infection model, had little effect on nasopharyngeal colonization. Our infection model revealed that B. pertussis can efficiently colonize the mouse nasopharynx, grow and spread within and between respiratory organs, evade robust host immunity, and persist for months. This experimental approach can measure aspects of the infection processes not observed in the conventional pneumonic infection model.

TWE-PRIL reverse signalling suppresses sympathetic axon growth and tissue innervation.

TWE-PRIL is a naturally occurring fusion protein of components of two TNF superfamily members: the extracellular domain of APRIL; and the intracellular and transmembrane domains of TWEAK with no known function. Here, we show that April-/- mice (which lack APRIL and TWE-PRIL) exhibited overgrowth of sympathetic fibres in vivo, and sympathetic neurons cultured from these mice had significantly longer axons than neurons cultured from wild-type littermates. Enhanced axon growth from sympathetic neurons cultured from April-/- mice was prevented by expressing full-length TWE-PRIL in these neurons but not by treating them with soluble APRIL. Soluble APRIL, however, enhanced axon growth from the sympathetic neurons of wild-type mice. siRNA knockdown of TWE-PRIL but not siRNA knockdown of APRIL alone also enhanced axon growth from wild-type sympathetic neurons. Our work reveals the first and physiologically relevant role for TWE-PRIL and suggests that it mediates reverse signalling.

BET 1: is the patient's perception of shortness of breath a useful triage tool in exacerbations of COPD?

A shortcut review was carried out to establish whether the degree of breathlessness in patients with an acute exacerbation of COPD is indicative of the severity of the exacerbation. Three hundred and forty-seven papers were found using the reported searches, of which five presented the best available evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these five papers are tabulated. It is concluded that increased shortness of breath is associated with a worse prognosis in patients with acute exacerbations of COPD. Dyspnoea assessment should be included in the triage process.

BET 1: The role of topical phenylephrine in non-traumatic epistaxis.

A short cut review of the literature was carried out to establish whether topical phenylephrine was an effective treatment for non-traumatic epistaxis. A single paper looked at this modality comparing it to another topical treatment. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses are tabulated. It is concluded that further more robust studies are needed to answer this question.

Social-media-enabled learning in emergency medicine: a case study of the growth, engagement and impact of a free open access medical education blog.

BACKGROUND: Clinicians are increasingly using social media for professional development and education. In 2012, we developed the St.Emlyn's blog, an open access resource dedicated to providing free education in the field of emergency medicine. OBJECTIVE: To describe the development and growth of this international emergency medicine blog. METHOD: We present a narrative description of the development of St.Emlyn's blog. Data on scope, impact and engagement were extracted from WordPress, Twitter and Google Analytics. RESULTS: The St.Emlyn's blog demonstrates a sustained growth in size and user engagement. Since inception in 2012, the site has been viewed over 1.25 million times with a linear year-on-year growth. We have published over 500 blog posts, each of which attracts a mean of 2466 views (range 382-69 671). The site has been viewed in nearly every country in the world, although the majority (>75%) of visitors come from the USA, UK and Australia. SUMMARY: This case study of an emergency medicine blog quantifies the reach and engagement of social-media-enabled learning in emergency medicine.

How events in emergency medicine impact doctors' psychological well-being.

BACKGROUND: Emergency medicine is a high-pressured specialty with exposure to disturbing events and risk. We conducted a qualitative study to identify which clinical events resulted in emotional disruption and the impact of these events on the well-being of physicians working in an ED. METHODS: We used the principles of naturalistic inquiry to conduct narrative interviews with physicians working in the ED at Central Manchester University Hospitals NHS Foundation Trust, between September and October 2016. Participants were asked, 'Could you tell me about a time when an event at work has continued to play on your mind after the shift in which it occurred was over?' Data were analysed using framework analysis. The study had three a priori themes reported here. Other emergent themes were analysed separately. RESULTS: We interviewed 17 participants. Within the first a priori theme ('clinical events') factors associated with emotional disruption included young or traumatic deaths, patients or situations that physicians could relate to, witnessing the impact of death on relatives, the burden of responsibility (including medical error) and conflict in the workplace. Under theme 2 (psychological and physical effects), participants reported substantial upset leading to substance misuse, sleep disruption and neglecting their own physical needs through preoccupation with caring. Within theme 3 (impact on relationships), many interviewees described becoming withdrawn from personal relationships following clinical events, while others described feeling isolated because friends and family were non-medical. CONCLUSIONS: Clinical events encountered in the ED can affect a physician's psychological and physical well-being. For many participants these effects were negative and long lasting.

BET 1: IN PATIENTS WITH SUSPECTED ACUTE CORONARY SYNDROME, DOES WELLENS' SIGN ON THE ELECTROCARDIOGRAPH IDENTIFY CRITICAL LEFT ANTERIOR DESCENDING ARTERY STENOSIS?

Wellens' syndrome consists of a history suggestive of an acute coronary syndrome and biphasic or deeply inverted T waves in ECG leads V2-V3. A shortcut review was carried out to establish whether this ECG pattern identifies patients with a critical left anterior descending artery stenosis. Six relevant papers were found. The clinical bottom line is that biphasic T-wave inversion in lead V2-V3 should alert the clinician to a probable critical stenosis of the left anterior descending artery.

BET 1: Lidocaine with propofol to reduce pain on injection.

A short review was carried out to see if mixing lidocaine with propofol is a safe and effective method in reducing the commonly reported pain at the injection site. Four relevant papers were found using the described search strategy. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these papers are tabulated. Although a promising idea, a paucity of good quality evidence suggests further needed research.

ProNGF promotes neurite growth from a subset of NGF-dependent neurons by a p75NTR-dependent mechanism.

The somatosensory and sympathetic innervation of the vertebrate head is derived principally from the neurons of trigeminal and superior cervical ganglia (SCG), respectively. During development, the survival of both populations of neurons and the terminal growth and branching of their axons in the tissues they innervate is regulated by the supply of nerve growth factor (NGF) produced by these tissues. NGF is derived by proteolytic cleavage of a large precursor protein, proNGF, which is recognised to possess distinctive biological functions. Here, we show that proNGF promotes profuse neurite growth and branching from cultured postnatal mouse SCG neurons. In marked contrast, proNGF does not promote the growth of trigeminal neurites. Studies using compartment cultures demonstrated that proNGF acts locally on SCG neurites to promote growth. The neurite growth-promoting effect of proNGF is not observed in SCG neurons cultured from p75(NTR)-deficient mice, and proNGF does not phosphorylate the NGF receptor tyrosine kinase TrkA. These findings suggest that proNGF selectively promotes the growth of neurites from a subset of NGF-responsive neurons by a p75(NTR)-dependent mechanism during postnatal development when the axons of these neurons are ramifying within their targets in vivo.

BET 1: Does apnoeic oxygenation reduce the risk of desaturation in patients requiring endotracheal intubation?

A shortcut review of the literature was carried out to establish whether the use of apnoeic oxygenation technique during endotracheal intubation reduces the incidence of critical desaturation. Four trials were found to be directly relevant to the three-part question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these papers are tabulated. The clinical bottom line is that there is emerging evidence that the use of apnoeic oxygenation decreases the incidence of critical desaturation during endotracheal intubation. Due to the heterogeneity of trials, however, further well-constructed and emergency department (ED)-based studies are probably warranted before conclusion can be drawn for daily emergency medicine practice.

Size-focusing synthesis of gold nanoclusters with p-mercaptobenzoic acid.

Etching or size-focusing methods are now widespread for preparation of atomically monodisperse thiolate-protected gold nanoparticles. Size-focusing methods are not widespread, however, in the production of water-soluble gold nanoparticles. Reported here is a new method for size-focusing of large gold nanoparticles utilizing p-mercaptobenzoic acid. We observe preferential formation of three large gold nanoparticles with approximate masses of 23, 51, and 88 kDa. On the basis of the stability of these masses against further etching or growth, they appear to be especially stable sizes. These sizes are not prominent after etching challenges with organosoluble ligands, and the 51 and 88 kDa sizes appear to be novel stable thiolate-protected gold cluster sizes. The overall trend in particle size distribution over time is also unusual, with larger sizes dominating at longer time points.

Gastrointestinal conditions related to tooth wear.

Gastro-oesophageal reflux disease (GORD) is a relatively common condition that occurs in adults and less commonly in children. It develops when the reflux of stomach contents into the oesophagus causes troublesome symptoms and/or complications. Signs and symptoms include heartburn, retrosternal discomfort, epigastric pain and hoarseness, dental erosion, chronic cough, burning mouth syndrome, halitosis and laryngitis. A proportion of patients will, however, have silent reflux. Strongly associated risk factors include family history, age, hiatus hernia, obesity and neurological conditions, such as cerebral palsy. There are different treatment options which may be considered for GORD, consisting of conservative, medical and surgical therapy. Dentists should be aware of the symptoms of GORD and dental signs of intrinsic erosion indicative of possible GORD so that they can question patients about this and, if appropriate, initiate a referral to a general medical practitioner.

Application of quasimetagenomics methods to define microbial diversity and subtype Listeria monocytogenes in dairy and seafood production facilities.

IMPORTANCE: In developed countries, the human diet is predominated by food commodities, which have been manufactured, processed, and stored in a food production facility. Little is known about the application of metagenomic sequencing approaches for detecting foodborne pathogens, such as L. monocytogenes, and characterizing microbial diversity in food production ecosystems. In this work, we investigated the utility of 16S rRNA amplicon and quasimetagenomic sequencing for the taxonomic and phylogenetic classification of Listeria culture enrichments of environmental swabs collected from dairy and seafood production facilities. We demonstrated that single-nucleotide polymorphism (SNP) analyses of L. monocytogenes metagenome-assembled genomes (MAGs) from quasimetagenomic data sets can achieve similar resolution as culture isolate whole-genome sequencing. To further understand the impact of genome coverage on MAG SNP cluster resolution, an in silico downsampling approach was employed to reduce the percentage of target pathogen sequence reads, providing an initial estimate of required MAG coverage for subtyping resolution of L. monocytogenes.

Clinical and radiographic assessment and restoration of maxillary sinus function in relation to oro-antral fistula closure: a systematic review.

BACKGROUND: The purpose of this study was to determine current practice in assessment of maxillary sinus health during oro-antral fistula closure. METHOD: A systematic review using specific MeSH headings between 1990 and September 2021 on Medline, Ovid, and PubMed was performed. The inclusion criterion was closure of oro-antral fistula in adult patients. Exclusion criteria were oro-antral fistula arising in children; or from trauma, malignancy, or developmental abnormality; or any osteonecrotic lesion of bone. Risk of bias for individual papers was not assessed. Oxford Centre for Evidence Based Medicine levels of evidence were recorded. RESULTS: 4309 papers were identified, and 119 were eligible for review. Nineteen were from otolaryngology (16%), 25 from combined ear, nose, and throat (ENT) and oral/oral and maxillofacial (OS/OMF) surgery (21%), and 75 from OS/OMF surgery (63%). Preoperative rhinoscopy and cross-sectional imaging were reported in 33 papers (28%), reflecting the role of ENT with or without OS/OMFS. Sixty-eight did not record any formal assessment of maxillary sinus health (57%), of which 60 were from OS/OMF surgery (50%). Use of computed tomography was reported in 58 papers (49%), and use of cone beam computed tomography was reported in 8 papers (7%) but did not correlate with assessment of sinus health. DISCUSSION: Most surgery for oro-antral fistual closure was undertaken without objective assessment of maxillary sinus health, pre- or postoperatively. The involvement of ENT was associated with formal assessment of maxillary sinus health.

Bbvac: A Live Vaccine Candidate That Provides Long-Lasting Anamnestic and Th17-Mediated Immunity against the Three Classical Bordetella spp.

Acute pathogens such as Bordetella pertussis can cause severe disease but are ultimately cleared by the immune response. This has led to the accepted paradigm that convalescent immunity is optimal and therefore broadly accepted as the "gold standard" against which vaccine candidates should be compared. However, successful pathogens like B. pertussis have evolved multiple mechanisms for suppressing and evading host immunity, raising the possibility that disruption of these mechanisms could result in substantially stronger or better immunity. Current acellular B. pertussis vaccines, delivered in a 5-dose regimen, induce only short-term immunity against disease and even less against colonization and transmission. Importantly, they provide modest protection against other Bordetella species that cause substantial human disease. A universal vaccine that protects against the three classical Bordetella spp. could decrease the burden of whooping cough-like disease in humans and other animals. Our recent work demonstrated that Bordetella spp. suppress host inflammatory responses and that disrupting the regulation of immunosuppressive mechanisms can allow the host to generate substantially stronger sterilizing immunity against the three classical Bordetella spp. Here, we identify immune parameters impacted by Bordetella species immunomodulation, including the generation of robust Th17 and B cell memory responses. Disrupting immunomodulation augmented the immune response, providing strong protection against the prototypes of all three classical Bordetella spp. as well as recent clinical isolates. Importantly, the protection in mice lasted for at least 15 months and was associated with recruitment of high numbers of B and T cells in the lungs as well as enhanced Th17 mucosal responses and persistently high titers of antibodies. These findings demonstrate that disrupting bacterial immunomodulatory pathways can generate much stronger and more protective immune responses to infection, with important implications for the development of better vaccines. IMPORTANCE Infectious diseases are a major cause of morbidity and mortality in the United States, accounting for over 40 million hospitalizations since 1998. Therefore, novel vaccine strategies are imperative, which can be improved with a better understanding of the mechanisms that bacteria utilize to suppress host immunity, a key mechanism for establishing colonization. Bordetella spp., the causative agents of whooping cough, suppress host immunity, which allows for persistent colonization. We discovered a regulator of a bacterial immunosuppressive pathway, which, when mutated in Bordetella spp., allows for rapid clearance of infection and subsequent generation of protective immunity for at least 15 months. After infection with the mutant strain, mice exhibited sterilizing immunity against the three classical Bordetella spp., suggesting that the immune response can be both stronger and cross-protective. This work presents a strategy for vaccine development that can be applied to other immunomodulatory pathogens.

Modeling the catarrhal stage of Bordetella pertussis upper respiratory tract infections in mice.

Pertussis (whooping cough) is a highly transmissible human respiratory disease caused by Bordetella pertussis, a human-restricted pathogen. Animal models generally involve pneumonic infections induced by depositing large numbers of bacteria in the lungs of mice. These models have informed us about the molecular pathogenesis of pertussis and guided development of vaccines that successfully protect against severe disease. However, they bypass the catarrhal stage of the disease, when bacteria first colonize and initially grow in the upper respiratory tract. This is a critical and highly transmissible stage of the infection that current vaccines do not prevent. Here, we demonstrate a model system in which B. pertussis robustly and persistently infects the nasopharynx of TLR4-deficient mice, inducing localized inflammation, neutrophil recruitment and mucus production as well as persistent shedding and occasional transmission to cage mates. This novel experimental system will allow the study of the contributions of bacterial factors to colonization of and shedding from the nasopharynx, as occurs during the catarrhal stage of pertussis, and interventions that might better control the ongoing circulation of pertussis.