Serine deamination by human serine racemase synergizes with antibiotics to curtail the replication of Chlamydia trachomatis.

The obligate intracellular bacterium, Chlamydia trachomatis, has evolved to depend on its human host for many metabolites, including most amino acids and three of the four nucleotides. In view of this, it is not surprising that depletion of a single amino acid in the host cell growth medium blocks chlamydial replication. Paradoxically, supra-normal levels of some amino acids also block productive replication of Chlamydia. Here, we have determined how elevated serine levels, generated by exogenous supplementation, impede chlamydial inclusion development and reduce the generation of infectious progeny. Our findings reveal that human serine racemase, which is broadly expressed in multiple tissues, potentiates the anti-chlamydial effect of elevated serine concentrations. In addition to reversibly converting l-serine to d-serine, serine racemase also deaminates serine via ß-elimination. We have determined that d-serine does not directly impact Chlamydia; rather, ammonia generated by serine deamination limits the productive chlamydial replication. Our findings imply that ammonia produced within host cells can traverse the chlamydial inclusion membrane. Further, this property of serine deaminase can be exploited to sensitize Chlamydia to concentrations of doxycycline that are otherwise not bactericidal. Because exogenously elevated levels of serine can be tolerated over extended periods, the broad expression pattern of serine racemase indicate it to be a host enzyme whose activity can be directed against multiple intracellular bacterial pathogens. From a therapeutic perspective, by demonstrating host metabolism can be skewed to generate an anti-bacterial metabolite that synergizes with antibiotics, we believe our results provide a new approach to target intracellular pathogens.

Synthesis and study of optical properties of a Gd3+-doped NaYF4 phosphor for phototherapy lamp application.

In recent trends, radiation falls under the narrowband ultraviolet-B region (305-315 nm) widely used in phototherapy lamp applications in the treatment of skin diseases. In this paper, we report a Gd3+-doped NaYF4 luminescent material synthesized for the first time using the low-temperature co-precipitation method. It crystallized into a face-centred cubic structure, as confirmed by X-ray diffraction characterization techniques and Rietveld refinement. The photoluminescence property of the as-prepared sample shows a highly intense, sharp emission band obtained at 311 nm, which belongs to the narrowband ultraviolet-B region and corresponds to the transition of the 6P7/2→8S7/2 level of the Gd3+ ions under 272 nm excitation (8S7/2 to 6IJ). The transitions of the Gd3+ ions are detected entirely with different concentrations of Gd3+ ions. Scanning electron microscopy analysis indicated that the average particle was 288 nm. The critical distance for energy transfer was calculated to be equal to 11.5017 Å. Dipole-dipole interaction is responsible for energy transfer, as analyzed by Dexter theory. These excellent optical characteristics, together with their highly efficient and low-cost synthesis approach, indicate that synthesized NaYF4:Gd3+ phosphors have excessive potential for phototherapeutic lamp applications.

Otolaryngology Care Disparities in American Indian Populations.

Our objectives were to quantify geographical disparities in otolaryngology care access with respect to American Indian (AI) populations and to identify gaps in care. Although increased incidence and mortality rates of ear, nose, and throat (ENT) conditions in AI populations are well documented, few studies address factors contributing to these differential outcomes. We conducted a cross-sectional study of US states with AI areas that either met the population threshold for the American Community Survey annual estimate or annual supplemental estimate. A 2-tailed t test was used to compare the geographic distribution of ENT providers practicing within AI areas against non-AI areas, showing a statistically significant difference (P < .001) in the concentration of providers (0.409 vs 2.233 providers per 100,000 patients). To our knowledge, this is the first study to explore geographic barriers contributing to AI disparities within otolaryngology.

An Integrative Model of ENT Healthcare for the Homeless Population.

OBJECTIVE: Our aim was to determine the need for otolaryngology care within the homeless population, identify barriers to access that the homeless population may face, and develop a model system which would address these needs with respect to the barriers. METHODS: A retrospective chart review of 812 patients seen between 1/25/16-3/21/2020 was performed. Charts were obtained from homeless patients seen at free general clinics held shelters in Chicago, IL (781 charts) and in Champaign, IL (31 charts). Records reporting at least one otolaryngology disease in a patient experiencing homelessness were included in this study. Patients were considered homeless if they resided at the shelter at the time of their appointment. To determine common barriers to care, a simple yes/no questionnaire was administered to residents at west-side Chicago homeless shelters. Questions addressed barriers to health care access that had been mentioned by patients seen at free clinics. RESULTS: Chart review findings demonstrated that 14.3% (n = 142) of all homeless patients seen at free in-shelter clinics were seen for ENT-related disorders. Survey results revealed that 76.3% (n = 71) of respondents believed that telemedicine services would be useful in shelters. 74.2% (n = 69) stated they were unable to afford prescribed medications. 93.5% (n = 87) stated that better access to transportation would increase their likelihood of seeking care. CONCLUSIONS: In our attempt to bridge this inequity, we have launched a hybrid in-person/virtual care program to improve access to otolaryngology care for the homeless community. LEVEL OF EVIDENCE: N/A Laryngoscope, 134:2705-2709, 2024.

Temporal evolution of chest radiographic appearances in COVID-19 with clinicoradiological associations: a multicentre United Kingdom resident-led study.

AIM: To describe the (a) frequency of improving, static, and worsening chest radiograph (CXR) appearances; (b) differences in demographic, initial rudimentary haematological and CXR variables and these patterns; and (c) frequency of different trajectories of serial CXR evolution, in COVID-19 patients presenting consecutively. MATERIALS AND METHODS: This multicentre retrospective study included all COVID-19 patients admitted from 1-30 April 2020, meeting the inclusion criteria across 24 (blinded) hospitals. Follow-up CXRs on admission, the subsequent (where available), and at 4-8 weeks were scored for the presence of parenchymal opacities across six zones. Three cohorts were defined: improved, static, and/or worsened. The chi-squared and Kruskal-Wallis tests were used to compare demographic, laboratory, and CXR variables. Trajectories of CXR evolution were assessed when all three CXRs were available (226 patients). RESULTS: Of 452 included patients (median age 66 years, interquartile range 54.3-79, 262 men), 211 (46.7%) improved, 140 (31%) were static, and 101 (22.3%) worsened. Improving patients were more likely younger, with a classic COVID-19 radiograph and higher initial CXR zonal severity scores (both p<0.001), while worsening patients had lower initial lymphocyte counts (p=0.008). The most frequent trajectory was worsened then improved (n=63, 27.9%) followed by static then improved (n=46, 20.4%) and static (n=42, 18.6%). CONCLUSION: Most patients with COVID-19 during the first wave of the pandemic demonstrated radiographic improvement; these patients were more likely younger with classic COVID-19 appearances and initially more extensive abnormality. Conversely, radiographic deterioration was associated with lower lymphocyte counts. The three most common trajectories were worsening then improvement, static then improvement, and static throughout.

Synthesis and study of luminescence properties of a deep red-emitting phosphor K2 LiAlF6 :Mn4+ for plant cultivation.

Light is the most important component in plant growth and development. This study synthesised a novel Mn4+ -doped K2 LiAlF6 red-emitting phosphor using the coprecipitation method. We observed that on addition of dopant Mn4+ ions to the host K2 LiAlF6 , its phase changed from rhombohedral to cubic due to the change in the lattice position of the atoms. When the atoms are excited at 468 nm, the K2 LiAlF6 :Mn4+ phosphor exhibited a red emission band ranging from 630 to 700 nm, centred at 638 nm, which matched well with the absorption spectra of phytochrome PR. The critical quenching content of Mn4+ ions was ~3 mol%. The critical distance between Mn4+ ions was determined to be 19.724 Å, and non-radiative energy transfer among the nearest-neighbour Mn4+ ions was the mechanism used for the concentration quenching effect. The Commission International de l'Eclairage (CIE) chromaticity coordinates of the K2 LiAlF6 :0.03 Mn4+ sample were (x = 0.7162, y = 0.2837). The luminescence mean decay time was calculated to be 8.29 ms. These results demonstrated the promising prospect of K2 LiAlF6 :Mn4+ as a red-emitting phosphor for application in red light-emitting diodes for plant cultivation.

Glutamine-rich regions of the disordered CREB transactivation domain mediate dynamic intra- and intermolecular interactions.

The cyclic AMP response element (CRE) binding protein (CREB) is a transcription factor that contains a 280-residue N-terminal transactivation domain and a basic leucine zipper that mediates interaction with DNA. The transactivation domain comprises three subdomains, the glutamine-rich domains Q1 and Q2 and the kinase inducible activation domain (KID). NMR chemical shifts show that the isolated subdomains are intrinsically disordered but have a propensity to populate local elements of secondary structure. The Q1 and Q2 domains exhibit a propensity for formation of short ß-hairpin motifs that function as binding sites for glutamine-rich sequences. These motifs mediate intramolecular interactions between the CREB Q1 and Q2 domains as well as intermolecular interactions with the glutamine-rich Q1 domain of the TATA-box binding protein associated factor 4 (TAF4) subunit of transcription factor IID (TFIID). Using small-angle X-ray scattering, NMR, and single-molecule Förster resonance energy transfer, we show that the Q1, Q2, and KID regions remain dynamically disordered in a full-length CREB transactivation domain (CREBTAD) construct. The CREBTAD polypeptide chain is largely extended although some compaction is evident in the KID and Q2 domains. Paramagnetic relaxation enhancement reveals transient long-range contacts both within and between the Q1 and Q2 domains while the intervening KID domain is largely devoid of intramolecular interactions. Phosphorylation results in expansion of the KID domain, presumably making it more accessible for binding the CBP/p300 transcriptional coactivators. Our study reveals the complex nature of the interactions within the intrinsically disordered transactivation domain of CREB and provides molecular-level insights into dynamic and transient interactions mediated by the glutamine-rich domains.

Reentrant DNA shells tune polyphosphate condensate size.

The ancient, inorganic biopolymer polyphosphate (polyP) occurs in all three domains of life and affects myriad cellular processes. An intriguing feature of polyP is its frequent proximity to chromatin, and in the case of many bacteria, its occurrence in the form of magnesium-enriched condensates embedded in the nucleoid, particularly in response to stress. The physical basis of the interaction between polyP and DNA, two fundamental anionic biopolymers, and the resulting effects on the organization of both the nucleoid and polyP condensates remain poorly understood. Given the essential role of magnesium ions in the coordination of polymeric phosphate species, we hypothesized that a minimal system of polyP, magnesium ions, and DNA (polyP-Mg2+-DNA) would capture key features of the interplay between the condensates and bacterial chromatin. We find that DNA can profoundly affect polyP-Mg2+ coacervation even at concentrations several orders of magnitude lower than found in the cell. The DNA forms shells around polyP-Mg2+ condensates and these shells show reentrant behavior, primarily forming in the concentration range close to polyP-Mg2+ charge neutralization. This surface association tunes both condensate size and DNA morphology in a manner dependent on DNA properties, including length and concentration. Our work identifies three components that could form the basis of a central and tunable interaction hub that interfaces with cellular interactors. These studies will inform future efforts to understand the basis of polyP granule composition and consolidation, as well as the potential capacity of these mesoscale assemblies to remodel chromatin in response to diverse stressors at different length and time scales.

Spatial and functional arrangement of Ebola virus polymerase inside phase-separated viral factories.

Ebola virus (EBOV) infection induces the formation of membrane-less, cytoplasmic compartments termed viral factories, in which multiple viral proteins gather and coordinate viral transcription, replication, and assembly. Key to viral factory function is the recruitment of EBOV polymerase, a multifunctional machine that mediates transcription and replication of the viral RNA genome. We show that intracellularly reconstituted EBOV viral factories are biomolecular condensates, with composition-dependent internal exchange dynamics that likely facilitates viral replication. Within the viral factory, we found the EBOV polymerase clusters into foci. The distance between these foci increases when viral replication is enabled. In addition to the typical droplet-like viral factories, we report the formation of network-like viral factories during EBOV infection. Unlike droplet-like viral factories, network-like factories are inactive for EBOV nucleocapsid assembly. This unique view of EBOV propagation suggests a form-to-function relationship that describes how physical properties and internal structures of biomolecular condensates influence viral biogenesis.

Evaluation of Wait Times for Otolaryngology Appointments in Illinois.

Objective: The objective of this study was to quantify the wait times that patients may encounter for common clinical diagnoses when seeking otolaryngology care, while determining whether a wait time disparity exists based on geographic location within Illinois. Methods: In November 2022, a list of Illinois otolaryngologists was obtained from www.entnet.org. Using a uniform script, each of the 291 otolaryngologists were contacted. The caller posed as a new patient with either sudden sensorineural hearing loss, a neck mass, or chronic sinusitis. Each clinic was called 3 times and wait times were recorded. One hundred fifty-eight otolaryngologists were included in the analysis. Results: The average statewide wait time for a new patient presenting with sudden unilateral hearing loss, a neck mass, and chronic sinusitis was 18.0, 22.6, and 25.5 days, respectively. There was no statistically significant difference between urban and rural wait times. Discussion: Although wait time differences were noted, the lack of urban versus rural p value significance may be attributed to the small sample size (n = 11) of rural otolaryngologists in Illinois. However, the overall wait times in this study were longer compared to those reported in other studies, suggesting that the current number of otolaryngologists in Illinois is inadequate to meet the public need. Implications for Practice: We have demonstrated that the current demand for otolaryngology care is outstripping the existing supply in Illinois. This suggests that an emphasis should be placed on training more otolaryngologists, or increasing the use of physician extenders, while incentivizing otolaryngologists to practice in rural areas. Level of Evidence: 5.

Topological Considerations in Biomolecular Condensation.

Biomolecular condensation and phase separation are increasingly understood to play crucial roles in cellular compartmentalization and spatiotemporal regulation of cell machinery implicated in function and pathology. A key aspect of current research is to gain insight into the underlying physical mechanisms of these processes. Accordingly, concepts of soft matter and polymer physics, the thermodynamics of mixing, and material science have been utilized for understanding condensation mechanisms of multivalent macromolecules resulting in viscoelastic mesoscopic supramolecular assemblies. Here, we focus on two topological concepts that have recently been providing key mechanistic understanding in the field. First, we will discuss how percolation provides a network-topology-related framework that offers an interesting paradigm to understand the complex networking of dense 'connected' condensate structures and, therefore, their phase behavior. Second, we will discuss the idea of entanglement as another topological concept that has deep roots in polymer physics and important implications for biomolecular condensates. We will first review some historical developments and fundamentals of these concepts, then we will discuss current advancements and recent examples. Our discussion ends with a few open questions and the challenges to address them, hinting at unveiling fresh possibilities for the modification of existing knowledge as well as the development of new concepts relevant to condensate science.

Academic clinical fellows in radiology: how can we improve success?

AIM: To survey past and current radiology academic clinical fellows (ACFs) for feedback on their experiences, academic achievements, challenges faced in balancing academic and clinical responsibilities, and opinion on how to optimise the fellowship programme. MATERIALS & METHODS: A 26-question online survey approved by the Royal College of Radiologists (RCR) Academic Committee was distributed over a 7-month period (June 2021 to January 2022) to current and past radiology ACFs via the National Institute for Health and Care Research (NIHR) integrated academic training imaging leads, radiology training programme directors, and social media. RESULTS: Thirty-five survey responses were received from past or present ACFs. Of the respondents, 42.8% (15/35) entered ACF training from another research post, and most continued their academic interests after ACF training (59.3%, 16/27 that had completed the post). The majority (22/35, 63%) had or were in the process of obtaining a postgraduate research degree. The most common academic outputs were scientific publications and national/international conference presentations. Most (23/35, 66%) would recommend the ACF post to colleagues, although some found it challenging balancing on-call and examination commitments during training. CONCLUSIONS: Entry into the radiology ACF programme is often after a prior academic post. Many ACFs appear to enjoy their fellowship experience and continue academic interests after training, some achieving higher research degrees. Challenges in balancing clinical workload require some flexibility from local clinical and academic supervisors. Suggestions for alternative structuring of the ACF pathway and how to optimise entry into these competitive posts are also outlined.

Coupling of binding and differential subdomain folding of the intrinsically disordered transcription factor CREB.

The cyclic AMP response element binding protein (CREB) contains a basic leucine zipper motif (bZIP) that forms a coiled coil structure upon dimerization and specific DNA binding. Although this state is well characterized, key features of CREB bZIP binding and folding are not well understood. We used single-molecule Förster resonance energy transfer (smFRET) to probe conformations of CREB bZIP subdomains. We found differential folding of the basic region and leucine zipper in response to different binding partners; a strong and previously unreported DNA-independent dimerization affinity; folding upon binding to nonspecific DNA; and evidence of long-range interdomain interactions in full-length CREB that modulate DNA binding. These studies provide new insights into DNA binding and dimerization and have implications for CREB function.

Short PolyA RNA Homopolymers Undergo Mg2+-Mediated Kinetically Arrested Condensation.

RNA-RNA interactions have increasingly been recognized for their potential to shape the mesoscale properties of biomolecular condensates, influencing morphology, organization, and material state through networking interactions. While most studies have focused on networking via Watson-Crick base pairing interactions, previous work has suggested a potential for noncanonical RNA-RNA interactions to also give rise to condensation and alter overall material state. Here, we test the phase separation of short polyA RNA (polyrA) homopolymers. We discover and characterize the potential for short polyrA sequences to form RNA condensates at lower Mg2+ concentrations than previously observed, which appear as internally arrested droplets with slow polyrA diffusion despite continued fusion. Our work also reveals a negative cooperativity effect between the effects of Mg2+ and Na+ on polyrA condensation. Finally, we observe that polyrA sequences can act as promoters of phase separation in mixed sequences. These results demonstrate the potential for noncanonical interactions to act as networking stickers, leading to specific condensation properties inherent to polyrA composition and structure, with implications for the fundamental physical chemistry of the system and function of polyA RNA in biology.

Indian Guidelines on Nebulization Therapy.

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

Design and Implementation of a Global Health and Underserved Care Track in an Otolaryngology Residency.

Despite widespread resident interest in global health and underserved care, few otolaryngology residency programs offer a formal global health experience. This article is the first to characterize a formal otolaryngology global health and underserved care track with a focus on how this curriculum integrates with and supplements resident education. Components of the track include longitudinal limited-resource field experiences in domestic and abroad settings, a related quality improvement project, and completion of a formalized global health educational curriculum. In addition to delivering humanitarian aid, residents in this track obtain a unique educational experience in all 6 core competencies of the Accreditation Council for Graduate Medical Education. Early barriers to implementation included identifying mentorship, securing funding, and managing busy resident schedules. In this work, we detail track components, schedule by track year, keys to implementation, and potential educational pitfalls.

Rural Otolaryngology Care Disparities: A Scoping Review.

OBJECTIVE: To broadly synthesize the literature regarding rural health disparities in otolaryngology, categorize findings, and identify research gaps to stimulate future work. STUDY DESIGN: Scoping review. DATA SOURCES: A comprehensive literature search was performed in the following databases: PubMed/MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, Google Scholar, and CINAHL. REVIEW METHODS: The methods were developed in concordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist. Peer-reviewed, English-language, US-based studies examining a rural disparity in otolaryngology-related disease incidence, prevalence, diagnosis, treatment, or outcome were included. Descriptive studies, commentaries, reviews, and letters to the editor were excluded. Studies published prior to 1980 were excluded. RESULTS: The literature search resulted in 1536 unique abstracts and yielded 79 studies that met final criteria for inclusion. Seventy-five percent were published after 2010. The distribution of literature was as follows: otology (34.2%), head and neck cancer (20.3%), endocrine surgery (13.9%), rhinology and allergy (8.9%), trauma (5.1%), laryngology (3.8%), other pediatrics (2.5%), and adult sleep (1.3%). Studies on otolaryngology health care systems also accounted for 10.1%. The most common topics studied were practice patterns (41%) and epidemiology (27%), while the Southeast (47%) was the most common US region represented, and database study (42%) was the most common study design. CONCLUSION: Overall, there was low-quality evidence with large gaps in the literature in all subspecialties, most notably facial plastic surgery, laryngology, adult sleep, and pediatrics. Importantly, there were few studies on intervention and zero studies on resident exposure to rural populations, which will be critical to making rural otolaryngology care more equitable in the future.