on

Physician Satisfaction Should Be the Measure of Electronic Health Record Quality for the Nation




on

Reply to Letter to Editor Concerning “Nocturnal Pressure Controlled Ventilation Improves Sleep Efficiency in Patients Receiving Mechanical Ventilation”




on

Nocturnal Pressure Support Ventilation: Truth or Dare?




on

The Evolution of Intermittent Mandatory Ventilation: Update and Implications for Home Care




on

Comparing Highs and Flows in Patients With COPD With Chronic Hypercapnic Respiratory Failure




on

The Challenge of Implementing Race-Neutral PFT Reference Equations




on

Supporting Evidence For Pulmonary Rehabilitation in the Treatment of Long COVID




on

Simulation in Mechanical Ventilation Training: Integrating Best Practices for Effective Education




on

Home Respiratory Strategies in Patients With COPD With Chronic Hypercapnic Respiratory Failure

BACKGROUND:Home noninvasive ventilation (NIV) may improve chronic hypercarbia in COPD and patient-important outcomes. The efficacy of home high-flow nasal cannula (HFNC) as an alternative is unclear.METHODS:We searched MEDLINE, Embase, Cochrane CENTRAL, Scopus, and ClinicalTrials.gov for randomized trials of subjects from inception to March 31, 2023, and updated the search on July 14, 2023. We performed a frequentist network meta-analysis and assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. We analyzed randomized controlled trials (RCTs) comparing NIV, HFNC, or standard care in adult subjects with COPD with chronic hypercapnic respiratory failure. Outcomes included mortality, COPD exacerbations, hospitalizations, and quality of life (St George Respiratory Questionnaire [SGRQ]).RESULTS:We analyzed 24 RCTs (1,850 subjects). We found that NIV may reduce the risk of death compared to standard care (relative risk 0.82 [95% CI 0.66–1.00]) and probably reduces exacerbations (relative risk 0.71 [95% CI 0.58–0.87]). HFNC probably reduces exacerbations compared to standard care (relative risk 0.77 [0.68–0.88]), but its effect on mortality is uncertain (relative risk 1.20 [95% CI 0.63–2.28]). HFNC probably improves SGRQ scores (mean difference −7.01 [95% CI −12.27 to −1.77]) and may reduce hospitalizations (relative risk 0.87 [0.69–1.09]) compared to standard care. No significant difference was observed between HFNC and NIV in reducing exacerbations.CONCLUSIONS:Both NIV and HFNC reduce exacerbation risks in subjects with COPD compared to standard care. HFNC may offer advantages in improving quality of life.




on

Downstream Effects of Market Changes on Inhalers: Impacts on Individuals With Chronic Lung Disease

COPD and asthma are two of the most common chronic lung diseases, affecting over 545 million people globally and 34 million in the United States. Annual health care costs related to chronic lung disease are estimated at €380 billion in the European Union, and $24–$50 billion in the United States averaging to $4,000 in out-of-pocket costs per person in the U.S. A full-text literature search was conducted for English publications between January 1, 2005–March 18, 2024. It returned over 5,000 publications that were further narrowed using key search words, resulting in 172 peer-reviewed articles. Using their experience and subject expertise, the authors further narrowed the peer-reviewed articles to 55 that were in their opinion relevant. Also, 38 recently published industry reports and news articles specific to downstream effects of inhaler market changes and the future impact were included. The literature suggests that individuals with chronic lung disease face increased challenges with access to inhaled medication due to rising medication costs, discontinuation of branded medications, introduction of generic medications not covered by insurance, exclusionary preferred drug list tactics that force health care providers into non-medical switching of medication or devices, and ongoing medication shortages. Providers experience ongoing hurdles in prescribing appropriate inhaled medications for individuals with chronic lung disease, including increased time and costs spent on administrative tasks due to inhaler denials, a loss of patient trust, and limits on their ability to prescribe appropriate inhaled medication for individuals with chronic lung disease.




on

Exploring the Impact of Varied Design Approaches and Materials in Respiratory Therapy Education




on

Effects of Lung Injury and Abdominal Insufflation on Respiratory Mechanics and Lung Volume During Time-Controlled Adaptive Ventilation

BACKGROUD:Lung volume measurements are important for monitoring functional aeration and recruitment and may help guide adjustments in ventilator settings. The expiratory phase of airway pressure release ventilation (APRV) may provide physiologic information about lung volume based on the expiratory flow-time slope, angle, and time to approach a no-flow state (expiratory time [TE]). We hypothesized that expiratory flow would correlate with estimated lung volume (ELV) as measured using a modified nitrogen washout/washin technique in a large-animal lung injury model.METHODS:Eight pigs (35.2 ± 1.0 kg) were mechanically ventilated using an Engström Carescape R860 on the APRV mode. All settings were held constant except the expiratory duration, which was adjusted based on the expiratory flow curve. Abdominal pressure was increased to 15 mm Hg in normal and injured lungs to replicate a combination of pulmonary and extrapulmonary lung injury. ELV was estimated using the Carescape FRC INview tool. The expiratory flow-time slope and TE were measured from the expiratory flow profile.RESULTS:Lung elastance increased with induced lung injury from 29.3 ± 7.3 cm H2O/L to 39.9 ± 15.1cm H2O/L, and chest wall elastance increased with increasing intra-abdominal pressures (IAPs) from 15.3 ± 4.1 cm H2O/L to 25.7 ± 10.0 cm H2O/L in the normal lung and 15.8 ± 6.0 cm H2O/L to 33.0 ± 6.2 cm H2O/L in the injured lung (P = .39). ELV decreased from 1.90 ± 0.83 L in the injured lung to 0.67 ± 0.10 L by increasing IAP to 15 mm Hg. This had a significant correlation with a TE decrease from 2.3 ± 0.8 s to 1.0 ± 0.1 s in the injured group with increasing insufflation pressures (ρ = 0.95) and with the expiratory flow-time slope, which increased from 0.29 ± 0.06 L/s2 to 0.63 ± 0.05 L/s2 (ρ = 0.78).CONCLUSIONS:Changes in ELV over time, and the TE and flow-time slope, could be used to demonstrate evolving lung injury during APRV. Using the slope to infer changes in functional lung volume represents a unique, reproducible, real-time, bedside technique that does not interrupt ventilation and may be used for clinical interpretation.




on

The Impact of Opioid Prescription on the Occurrence and Outcome of Pneumonia: A Nationwide Cohort Study in South Korea

BACKGROUND:Opioids are known to cause respiratory depression, aspiration, and to suppress the immune system. This study aimed to investigate the relationship between short- and long-term opioid use and the occurrence and clinical outcomes of pneumonia in South Korea.METHODS:The data for this population-based retrospective cohort analysis were obtained from the South Korean National Health Insurance Service. The opioid user group consisted of those prescribed opioids in 2016, while the non-user group, who did not receive opioid prescriptions that year, was selected using a 1:1 stratified random sampling method. The opioid users were categorized into short-term (1–89 d) and long-term (≥90 d) users. The primary end point was pneumonia incidence from January 1, 2017–December 31, 2021, with secondary end points including pneumonia-related hospitalizations and mortality rates during the study period.RESULTS:In total, 4,556,606 adults were enrolled (opioid group, 2,070,039). Opioid users had a 3% higher risk of pneumonia and an 11% higher risk of pneumonia requiring hospitalization compared to non-users. Short-term users had a 3% higher risk of pneumonia, and long-term users had a 4% higher risk compared to non-users (P < .001). Additionally, short-term users had an 8% higher risk of hospital-treated pneumonia, and long-term users had a 17% higher risk compared to non-users (P < .001).CONCLUSIONS:Both short- and long-term opioid prescriptions were associated with higher incidences of pneumonia and hospital-treated pneumonia. In addition, long-term opioid prescriptions were linked to higher mortality rates due to pneumonia.




on

Effect of Fasting Prior to Extubation on Prevalence of Empty Stomach in Enterally Fed and Mechanically Ventilated Patients

BACKGROUND:Practice on fasting prior to extubation in critically ill patients is variable. Efficacy of fasting in reducing gastric volume has not been well established. The primary objective of this study was to assess the effect of 4 h of fasting on prevalence of empty stomach using gastric ultrasonography in critically ill subjects who are fasted for extubation. The secondary objectives were to evaluate the change in gastric volumes during 4 h of fasting and to determine factors associated with empty stomach after fasting.METHODS:This was a single-center, prospective, observational study on adult ICU subjects who were enterally fed for at least 6 h continuously and mechanically ventilated. Gastric ultrasound was performed immediately prior to commencement of fasting, after 4 h of fasting, and after nasogastric (NG) aspiration after 4 h of fasting. An empty stomach was defined as a gastric volume ≤ 1.5 mL/kg.RESULTS:Forty subjects were recruited, and 38 (95%) had images suitable for analysis. The prevalence of empty stomach increased after 4 h of fasting (25 [65.8%] vs 31 [81.6%], P = .041) and after 4 h of fasting with NG aspiration (25 [65.8%] vs 34 [89.5%], P = .008). There was a significant difference in median (interquartile range) gastric volume per body weight between before fasting and 4 h after fasting (1.0 [0.5–1.8] mL/kg vs 0.4 [0.2–1.0] mL/kg, P < .001). No patient factors were associated with higher prevalence of empty stomach after 4 h of fasting.CONCLUSIONS:Most mechanically ventilated subjects had empty stomachs prior to fasting for extubation. Fasting for 4 h further increased the prevalence of empty stomach at extubation to > 80%.




on

The Impact of Increased PEEP on Hemodynamics, Respiratory Mechanics, and Oxygenation in Pediatric ARDS

BACKGROUND:PEEP is a cornerstone treatment for children with pediatric ARDS. Unfortunately, its titration is often performed solely by evaluating oxygen saturation, which can lead to inadequate PEEP level settings and consequent adverse effects. This study aimed to assess the impact of increasing PEEP on hemodynamics, respiratory system mechanics, and oxygenation in children with ARDS.METHODS:Children receiving mechanical ventilation and on pressure-controlled volume-guaranteed mode were prospectively assessed for inclusion. PEEP was sequentially changed to 5, 12, 10, 8 cm H2O, and again to 5 cm H2O. After 10 min at each PEEP level, hemodynamic, ventilatory, and oxygenation variables were collected.RESULTS:A total of 31 subjects were included, with median age and weight of 6 months and 6.3 kg, respectively. The main reasons for pediatric ICU admission were respiratory failure caused by acute viral bronchiolitis (45%) and community-acquired pneumonia (32%). Most subjects had mild or moderate ARDS (45% and 42%, respectively), with a median (interquartile range) oxygenation index of 8.4 (5.8–12.7). Oxygen saturation improved significantly when PEEP was increased. However, although no significant changes in blood pressure were observed, the median cardiac index at PEEP of 12 cm H2O was significantly lower than that observed at any other PEEP level (P = .001). Fourteen participants (45%) experienced a reduction in cardiac index of > 10% when PEEP was increased to 12 cm H2O. Also, the estimated oxygen delivery was significantly lower, at 12 cm H2O PEEP. Finally, respiratory system compliance significantly reduced when PEEP was increased. At a PEEP of 12 cm H2O, static compliance had a median reduction of 25% in relation to the initial assessment (PEEP of 5 cm H2O).CONCLUSIONS:Although it may improve arterial oxygen saturation, inappropriately high PEEP levels may reduce cardiac output, oxygen delivery, and respiratory system compliance in pediatric subjects with ARDS with low potential for lung recruitability.




on

Invasive Mechanical Ventilation and Risk of Hospital-Acquired Venous Thromboembolism

BACKGROUND:This study sought to estimate the overall cumulative incidence and odds of Hospital-acquired venous thromboembolism (VTE) among critically ill children with and without exposure to invasive ventilation. In doing so, we also aimed to describe the temporal relationship between invasive ventilation and hospital-acquired VTE development.METHODS:We performed a retrospective cohort study using Virtual Pediatric Systems (VPS) data from 142 North American pediatric ICUs among children < 18 y of age from January 1, 2016–December 31, 2022. After exclusion criteria were applied, cohorts were identified by presence of invasive ventilation exposure. The primary outcome was cumulative incidence of hospital-acquired VTE, defined as limb/neck deep venous thrombosis or pulmonary embolism. Multivariate logistic regression was used to determine whether invasive ventilation was an independent risk factor for hospital-acquired VTE development.RESULTS:Of 691,118 children studied, 86,922 (12.4%) underwent invasive ventilation. The cumulative incidence of hospital-acquired VTE for those who received invasive ventilation was 1.9% and 0.12% for those who did not (P < .001). The median time to hospital-acquired VTE after endotracheal intubation was 6 (interquartile range 3–14) d. In multivariate models, invasive ventilation exposure and duration were each independently associated with development of hospital-acquired VTE (adjusted odds ratio 1.64 [95% CI 1.42–1.86], P < .001; and adjusted odds ratio 1.03 [95% CI 1.02–1.03], P < .001, respectively).CONCLUSIONS:In this multi-center retrospective review from the VPS registry, invasive ventilation exposure and duration were independent risk factors for hospital-acquired VTE among critically ill children. Children undergoing invasive ventilation represent an important target population for risk-stratified thromboprophylaxis trials.




on

Quantitative Computed Tomography and Response to Pronation in COVID-19 ARDS

BACKGROUND:The use of prone position (PP) has been widespread during the COVID-19 pandemic. Whereas it has demonstrated benefits, including improved oxygenation and lung aeration, the factors influencing the response in terms of gas exchange to PP remain unclear. In particular, the association between baseline quantitative computed tomography (CT) scan results and gas exchange response to PP in invasively ventilated subjects with COVID-19 ARDS is unknown. The present study aimed to compare baseline quantitative CT results between subjects responding to PP in terms of oxygenation or CO2 clearance and those who did not.METHODS:This was a single-center, retrospective observational study including critically ill, invasively ventilated subjects with COVID-19–related ARDS admitted to the ICUs of Niguarda Hospital between March 2020–November 2021. Blood gas samples were collected before and after PP. Subjects in whom the PaO2/FIO2 increase was ≥ 20 mm Hg after PP were defined as oxygen responders. CO2 responders were defined when the ventilatory ratio (VR) decreased during PP. Automated quantitative CT analyses were performed to obtain tissue mass and density of the lungs.RESULTS:One hundred twenty-five subjects were enrolled, of which 116 (93%) were O2 responders and 51 (41%) CO2 responders. No difference in quantitative CT characteristics and oxygen were observed between responders and non-responders (tissue mass 1,532 ± 396 g vs 1,654 ± 304 g, P = .28; density −544 ± 109 HU vs −562 ± 58 HU P = .42). Similar findings were observed when dividing the population according to CO2 response (tissue mass 1,551 ± 412 g vs 1,534 ± 377 g, P = .89; density −545 ± 123 HU vs −546 ± 94 HU, P = .99).CONCLUSIONS:Most subjects with COVID-19–related ARDS improved their oxygenation at the first pronation cycle. The study suggests that baseline quantitative CT scan data were not associated with the response to PP in oxygenation or CO2 in mechanically ventilated subjects with COVID-19–related ARDS.




on

Perspectives on Using Race in Pulmonary Function Testing: A National Survey of Fellows and Program Directors

BACKGROUND:Pulmonary function tests (PFTs) have historically used race-specific prediction equations. The recent American Thoracic Society guidelines recommend the use of a race-neutral approach in prediction equations. There are limited studies centering the opinions of practicing pulmonologists on the use of race in spirometry. Provider opinion will impact adoption of the new guideline. The aim of this study was to ascertain the beliefs of academic pulmonary and critical care providers regarding the use of race as a variable in spirometry prediction equations.METHODS:We report data from 151 open-ended responses from a voluntary, nationwide survey (distributed by the Association of Pulmonary Critical Care Medicine Program Directors) of academic pulmonary and critical care providers regarding the use of race in PFT prediction equations. Responses were coded using inductive and deductive methods, and a thematic content analysis was conducted.RESULTS:There was a balanced distribution of opinions among respondents supporting, opposing, or being unsure about the incorporation of race in spirometry prediction equations. Responses demonstrated a wide array of understanding related to the concept and definition of race and its relationship to physiology.CONCLUSIONS:There was no consensus among providers regarding the use of race in spirometry prediction equations. Concepts of race having biologic implications persist among pulmonary providers and will likely affect the uptake of the Global Lung Function Initiative per the American Thoracic Society guidelines.




on

Rehabilitation Is Associated With Improvements in Post-COVID-19 Sequelae

BACKGROUND:Post–COVID-19 syndrome has affected millions of people, with rehabilitation being at the center of non-pharmacologic care. However, numerous published studies show conflicting results due to, among other factors, considerable variation in subject characteristics. Currently, the effects of age, sex, time of implementation, and prior disease severity on the outcomes of a supervised rehabilitation program after COVID-19 remain unknown.METHODS:This was a non-randomized case-control study. Subjects with post–COVID-19 sequelae were enrolled. Among study participants, those who could attend an 8-week, supervised rehabilitation program composed the intervention group, whereas those who couldn’t the control group. Measurements were collected at baseline and 8 weeks thereafter.RESULTS:Study groups (N = 119) had similar baseline measurements. Participation in rehabilitation (n = 47) was associated with clinically important improvements in the 6-min walk test (6MWT) distance, adjusted (for potential confounders) odds ratio (AOR) 4.56 (95% CI 1.95–10.66); 1-min sit-to-stand test, AOR 4.64 (1.88-11.48); Short Physical Performance Battery, AOR 7.93 (2.82–22.26); health-related quality of life (HRQOL) 5-level EuroQol-5D (Visual Analog Scale), AOR 3.12 (1.37–7.08); Montreal Cognitive Assessment, AOR 6.25 (2.16–18.04); International Physical Activity Questionnaire, AOR 3.63 (1.53–8.59); Fatigue Severity Scale, AOR 4.07 (1.51–10.98); Chalder Fatigue Scale (bimodal score), AOR 3.33 (1.45–7.67); Modified Medical Research Council dyspnea scale (mMRC), AOR 4.43 (1.83–10.74); Post–COVID-19 Functional Scale (PCFS), AOR 3.46 (1.51–7.95); and COPD Assessment Test, AOR 7.40 (2.92–18.75). Time from disease onset was marginally associated only with 6MWT distance, AOR 0.99 (0.99–1.00). Prior hospitalization was associated with clinically important improvements in the mMRC dyspnea scale, AOR 3.50 (1.06–11.51); and PCFS, AOR 3.42 (1.16–10.06). Age, sex, and ICU admission were not associated with the results of any of the aforementioned tests/grading scales.CONCLUSIONS:In this non-randomized, case-control study, post–COVID-19 rehabilitation was associated with improvements in physical function, activity, HRQOL, respiratory symptoms, fatigue, and cognitive impairment. These associations were observed independently of timing of rehabilitation, age, sex, prior hospitalization, and ICU admission.




on

Comparison of Web-Based and On-Site Lung Simulators for Education in Mechanical Ventilation

BACKGROUND:Training in mechanical ventilation is a key goal in critical care fellowship education. Web-based simulators offer a cost-effective and readily available alternative to traditional on-site simulators. However, it is unclear how effective they are as teaching tools. In this study, we evaluated the test scores of fellows who underwent mechanical ventilation training by using a web-based simulator compared with fellows who used an on-site simulator during a mechanical ventilation course.METHODS:This was a nonrandomized controlled trial conducted as part of a mechanical ventilation course that involved 70 first-year critical care fellows. The course was identical except for the simulation technology used. One group of instructors used a traditional on-site simulator, the ASL 5000 Lung Solution (n = 39). The second group was instructed in using a web-based simulator, VentSim (n = 31). Each fellow completed a pre-course test and a post-course test by using a validated, case-based ventilator waveform examination that consisted of 5 questions with a total possible score of 100. The primary outcome was a comparison of the mean scores on the posttest between the 2 groups. The study was designed as a non-inferiority trial with a predetermined margin of 10 points.RESULTS:There was no significant difference in the mean ± SD pretest scores between the web-based and the on-site groups (21.1 ± 12.6 and 26.9 ± 13.6 respectively; P = .11). The mean ± SD posttest scores were 45.6 ± 25.0 for the web-based simulator and 43.4 ± 16.5 for on-site simulator (mean difference 2.2; one-sided 95% CI –7.0 to ∞; Pnon-inferiority = .02 [non-inferiority confirmed]). Changes in mean ± SD scores (posttest – pretest) were 25.9 ± 20.9 for the web-based simulator and 16.5 ± 15.9 for the on-site simulator (mean difference 9.4, one-sided 95% CI 0.9 to ∞; Pnon-inferiority < .001 [non-inferiority confirmed]).CONCLUSIONS:In the education of first-year critical care fellows on mechanical ventilation waveform analysis, a web-based mechanical ventilation simulator was non-inferior to a traditional on-site mechanical ventilation simulator.




on

Prevalence of Dental Caries and Utilization of Dental Services among WIC-participating Children: A scoping review

Purpose Low-income children experience disproportionately high rates of dental caries and challenges in accessing dental care compared to their higher-income peers. The purpose of this scoping review was to examine the prevalence of dental caries and dental service utilization among Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) enrolled children.Methods The literature search and review were conducted between September 2023 and February 2024. The review followed the PRISMA-ScR reporting guidelines and included three databases: PubMed, CINAHL, and Dentistry & Oral Sciences Source. The study focused on children aged one to five participating in WIC within the United States (US) and aimed to determine the prevalence of dental service utilization and dental caries in the targeted population.Results This review includes twelve articles that are quantitative observational studies conducted from February 2001 to February 2023. Most of the studies were conducted in WIC programs in the Southern and Midwest regions of the US. Dental caries rates decreased by 61.8% from 2004 to 2016, with the highest prevalence in 2004, and the lowest prevalence in 2016. Dental service utilization among WIC children increased by 56.9% from 1992 to 2020.Conclusion There has been an increase in dental service utilization among WIC-enrolled children, with an overall decrease in dental caries over the last two decades. However, the prevalence of dental caries remains disproportionately high for children enrolled in WIC when compared to non-participants. To develop effective dental interventions for children enrolled in WIC, it is fundamental to identify the unique determinants of dental caries in this population.




on

Intraprofessional Education Experiences in Dentistry: Dental hygienists&#x2019; perceptions of collaboration with dentists

Purpose Health care professionals (HCPs) working collaboratively can improve patient outcomes and also increase their understanding of each other’s professional roles. This descriptive study aimed to explore dental hygienists’ perceptions of collaboration with dentists and intraprofessional educational (IntraPE) experiences.Methods A convenience sampling method was used to assess DHs perceptions of collaboration with dentists using the Interprofessional Collaboration Scale (ICS), a validated scale that measures perceptions of communication, accommodation, and isolation among HCPs. One open-ended question was added to explore IntraPE. Demographics, work characteristics and responses from the ICS were analyzed using frequency, mean, standard deviation, Pearson’s correlation, t-test, ANOVA, and multivariable regression. Responses from the open-ended question were transcribed, organized, and coded. Themes were identified using the Delve Qualitative Analysis Tool.Results Of the 264 participants, the average age was 38.9, and most identified as female (98.9%). Data analysis revealed that DHs had positive perceptions of collaboration with dentists. Significant relationships were found between ICS factor accommodation and the average number of patients treated per day (rs = −0.242, p<0.001), dentists’ age (rs = −.145, p<0.05). Isolation showed a significant negative correlation with the average number of patients treated per day (rs = −0.156, p<0.05). Most reported having no opportunities for IntraPE education experiences with dentists. Five categories of themes were identified from the open-ended question: shared academic setting, clinic dentist, externships, desire for more shared learning, and shared patient experiences.Conclusion Dental hygienists in this study had an overall more positive than negative perception of collaboration with dentists. Dental and dental hygiene programs should focus on intraprofessional education experiences to continue to enhance collaboration.




on

Comparison of Needle Depth Techniques for the Posterior Superior Alveolar Block

Purpose The posterior superior alveolar (PSA) block injection is one of many techniques used to provide profound anesthesia for invasive dental procedures. This technique has a high success rate but is not without complication risks. The purpose of this study was to determine if pulpal anesthesia of the maxillary second molar could be achieved using a reduced needle depth of 10mm or 5mm compared to the traditional needle depth of 16mm.Methods Sixty participants were asked to participate in three sessions. Each session started with a pre neural response test, followed by one randomized needle depth PSA injection, and ending with a post neural response test. The neural response test consisted of two parts, a cold refrigerant and a dental probe, on the buccal and interproximal surface of the maxillary second molar. After receiving a positive neural response, each participant received a posterior superior alveolar block injection using a short (21mm), 27-gauge dental needle with a randomized needle penetration depth of 16mm, 10mm, or 5mm. A post neural response test consisting of the same two parts as the pre-test was conducted on the maxillary second molar to evaluate for profound anesthesia.Results Positive neural responses were obtained from 100% of the participants (n=167) during the pre-tests. Study results demonstrated an 85% success rate at the traditional 16mm needle depth and a 93% and 92% success rates for the reduced needle depths of 10mm and 5mm, respectively. Pulpal anesthesia of the maxillary second molar had been achieved at all three needle depths with no statistically significant difference in the rate of success. Furthermore, there were no adverse events observed.Conclusion The reduced needle depth technique showed promise in achieving desired results of pulpal anesthesia with a reduced risk for complications associated with the PSA block injection. Additional studies are recommended to achieve evidence-based support for this reduced needle depth technique.




on

Effects of Ultrasonic Use on Hearing Loss in Dental Hygienists: A matched pairs design study

Purpose Dental professionals are exposed to hazardous noise levels on a daily basis in clinical practice. The purpose of this study was to compare the hearing status of dental hygienists who utilize ultrasonic scalers in the workplace compared to age-matched control participants (non-dental hygienists) who were not exposed to ultrasonic noise.Methods A convenience sample of nineteen dental hygienists (experimental) and nineteen non-dental hygienists (control) was recruited for this study. A matched pairs design was utilized; participants in each group were matched based on age and gender to eliminate confounding variables. The testing procedure consisted of an audiologist performing a series of auditory tests including otoacoustic emissions test, pure-tone audiometry, and tympanometry on the experimental and control groups.Results In the right ear, there were notable differences from 1000 Hz – 10,000 Hz and in the left ear from 6000 Hz – 10,000 Hz, with higher hearing thresholds in the experimental group of dental hygienists. While 56% of the univariate tests conducted on how many days were worked per week showed statistical significance, the regression line slope indicated those that worked more days had better hearing statuses. The variables for years in practice for dental hygienists, how many of those years were full-time employment, and how many years the dental hygienist had used an ultrasonic scaling device, also had many significant univariate tests for the experimental group only. These variables were more likely to serve as proxies representing true noise exposure. The paired t-test between the groups demonstrated statistically significant differences between the experimental and control group at 9000 Hz in both ears.Conclusion While results from this study demonstrated various qualitative differences in hearing status of the control group (non-dental hygienists) and experimental group (dental hygienists), age was found to be the most critical variable. Furthermore, this data demonstrated differences in hearing status based on various frequencies between dental hygienists and age-matched controls that should be further explored with a larger population.




on

Identification and Root Cause Analysis of the Visible Particles Commonly Encountered in the Biopharmaceutical Industry

Visible particle is an important issue in the biopharmaceutical industry, and it may occur across all the stages in the life cycle of biologics. Upon the occurrence of visible particles, it is often necessary to conduct chemical identification and root cause analysis to safeguard the safety and efficacy of the biotherapeutic products. In this article, we present a number of typical particles and relevant root cause analysis in the categories of extrinsic, intrinsic, and inherent particles that are commonly encountered in the biopharma industry. In particular, the optical images of particles obtained both in situ and after isolation are provided, along with spectral and elemental information. The particle identification was carried out with multiple microscopic and microspectroscopic techniques, including stereo optical microscopy, Fourier-transform infrared microscopy, confocal Raman microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Both commercial and in-house spectral databases were used for comparison and identification. In addition to particle identification, we placed significant efforts on the root cause analysis of the addressed particles with the intention to provide a relatively whole picture of the particle-related issues and practical references to particle mitigation for our peers in the biopharmaceutical industry.




on

Impact of Dimensional Variability of Primary Packaging Materials on the Break-Loose and Gliding Forces of Prefilled Syringes

A prefilled syringe (PFS) should be able to be adequately and consistently extruded during injection for optimal safe drug delivery and accurate dosing. To facilitate appropriate break-loose and gliding forces (BLGFs) required during injection, certain primary packaging materials (PPMs) such as the syringe barrel and plunger are usually coated with silicone oil, which acts as a lubricant. Due to its direct contact with drug, silicone oil can increase the number of particles in the syringe, which could lead to adverse interactions. Compliance with regulatory-defined silicone oil quantities in certain drug products, such as ophthalmics, presents a trade-off with the necessity for desirable low and consistent BLGF. In addition to its siliconization, the dimensional accuracy of the PPM has an important role in controlling the BLGF. The dimensions of the PPM are individualized depending on the product and its design and have certain tolerances that must be met during manufacturing. Most studies on ophthalmics focused on the adverse interactions between silicone oil and the drug. To the authors' knowledge, there have been no public studies so far that have investigated the impact of the dimensional variability of the PPM on the BLGF in ophthalmic PFSs. In this study, we applied advanced optical shaft and tactile measuring technologies to investigate this impact. The syringes investigated were first sampled during aseptic production and tested for the BLGF. Subsequently, defined dimensions of the PPM were measured individually. The results showed that the dimensional variability of the PPM can have a negative impact on the BLGF, despite their conformity to specifications, which indicates that the currently available market quality of PPMs is improvable for critical drug products such as ophthalmics. This study could serve as an approach to define product-specific requirements for primary packaging combinations and thus appropriate specifications based on data during the development stage of drug products.




on

Comparison of Binary Alcohol/Water Solvent Systems to Blood for Extractions of Blood-Contacting Medical Devices

The analysis of extractables and leachables and subsequent risk assessment is an important aspect of the determination of biocompatibility for many medical devices. Leachable chemicals have the potential to pose a toxicological risk to patients, and therefore it is required that they be adequately characterized and assessed for potential safety concerns. One important consideration in the assessment of leachables is the choice of a suitable simulating solvent intended to replicate the use condition for the device and its biological environment. This aspect of study design is especially difficult for blood-contacting medical devices due to the complexity of simulating the biological matrix. This publication reports a comparison of the extracting power of different binary solvent mixtures and saline in comparison with whole blood for a bloodline tubing set connected to a hemodialyzer. Ten different known extractables, spanning a range of physicochemical properties and molecular weights, were quantified. The results indicated that for low-molecular-weight analytes, a suitable exaggeration for whole blood can be obtained using a low-concentration ethanol/water mixture (20%), and in general, extracted quantity increases with the concentration of alcohol cosolvent. For polyvinylpyrrolidone, the opposite trend was observed, as solubility of the polymer was found to decrease with increasing alcohol concentration, resulting in lower extracted quantities at high alcohol concentrations. Analysis of ethanol/water concentrations in the extract solutions post extraction indicated no change in solvent composition.




on

Development and Validation of a Customized Amplex UltraRed Assay for Sensitive Hydrogen Peroxide Detection in Pharmaceutical Water

For clean-room technologies such as isolators and restricted access barrier systems (RABS), decontamination using hydrogen peroxide (H2O2) is increasingly attractive to fulfill regulatory requirements. Several approaches are currently used, ranging from manual wipe disinfection to vapor phase hydrogen peroxide (VPHP) or automated nebulization sanitization. Although the residual airborne H2O2 concentration can be easily monitored, detection of trace H2O2 residues in filled products is rather challenging. To simulate the filling process in a specific clean room, technical runs with water for injection (WfI) are popular. Thus, the ability to detect traces of H2O2 in water is an important prerequisite to ensure a safe and reliable use of H2O2 for isolator or clean room decontamination. The objective of this study was to provide a validated quantitative, fluorometric Amplex UltraRed assay, which satisfies the analytical target profile of quantifying H2O2 in WfI at low nanomolar to low micromolar concentrations (ppb range) with high accuracy and high precision. The Amplex UltraRed technology provides a solid basis for this purpose; however, no commercial assay kit that fulfills these requirements is available. Therefore, a customized Amplex UltraRed assay was developed, optimized, and validated. This approach resulted in an assay that is capable of quantifying H2O2 in WfI selectively, sensitively, accurately, precisely, and robustly. This assay is used in process development and qualification approaches using WfI in H2O2-decontaminated clean rooms and isolators.




on

Degradation of Obidoxime Chloride Solution for Injection upon Long-Term Storage under Field Conditions of Mediterranean Climate vs the Controlled Environment

Obidoxime chloride is an antidote for nerve gas intoxication. As an emergency medicine, it is being stored by the Israel Defense Forces (IDF) scattered throughout Israel in depots without a controlled environment (field conditions), thus being exposed to high and fluctuating temperatures. These conditions do not meet the manufacturer’s requirements. In addition, due to possible supply shortages, the utilization of expired batches was suggested. The current work investigated these matters. Long-term (15 years) storage under different conditions was initiated. Chemical stability and toxicity in rats were assessed. No difference was found between field conditions vs the controlled environment. The obidoxime assay remained >95% for 5 years and >90% for 7 years. The pH remained above the lower specification limit for 7–8 years. The major degradation product, 4-pyridinealdoxime, surpassed the allowed limit at 5 years. The content of total unknown impurities reached its maximum allowed by the IDF limit at 4–5 years. Threefold higher than clinically utilized doses of valid-to-date Toxogonin batches administered to rats did not cause any abnormality. However, expired batches produced significant toxic effects. Although no difference was found between storage of obidoxime ampoules when adhering to manufacturer’s recommendations vs field conditions, accumulation of degradants over the limit allowed by the IDF at 4–5 years of storage and the toxicity of the expired batches observed in rats led the IDF to a decision to shorten the shelf-life of this product from 5 to 4 years when stored in an uncontrolled environment of the Mediterranean climate.




on

NEAT1 promotes genome stability via m6A methylation-dependent regulation of CHD4 [Research Papers]

Long noncoding (lnc)RNAs emerge as regulators of genome stability. The nuclear-enriched abundant transcript 1 (NEAT1) is overexpressed in many tumors and is responsive to genotoxic stress. However, the mechanism that links NEAT1 to DNA damage response (DDR) is unclear. Here, we investigate the expression, modification, localization, and structure of NEAT1 in response to DNA double-strand breaks (DSBs). DNA damage increases the levels and N6-methyladenosine (m6A) marks on NEAT1, which promotes alterations in NEAT1 structure, accumulation of hypermethylated NEAT1 at promoter-associated DSBs, and DSB signaling. The depletion of NEAT1 impairs DSB focus formation and elevates DNA damage. The genome-protective role of NEAT1 is mediated by the RNA methyltransferase 3 (METTL3) and involves the release of the chromodomain helicase DNA binding protein 4 (CHD4) from NEAT1 to fine-tune histone acetylation at DSBs. Our data suggest a direct role for NEAT1 in DDR.




on

A germline PAF1 paralog complex ensures cell type-specific gene expression [Research Papers]

Animal germline development and fertility rely on paralogs of general transcription factors that recruit RNA polymerase II to ensure cell type-specific gene expression. It remains unclear whether gene expression processes downstream from such paralog-based transcription is distinct from that of canonical RNA polymerase II genes. In Drosophila, the testis-specific TBP-associated factors (tTAFs) activate over a thousand spermatocyte-specific gene promoters to enable meiosis and germ cell differentiation. Here, we show that efficient termination of tTAF-activated transcription relies on testis-specific paralogs of canonical polymerase-associated factor 1 complex (PAF1C) proteins, which form a testis-specific PAF1C (tPAF). Consequently, tPAF mutants show aberrant expression of hundreds of downstream genes due to read-in transcription. Furthermore, tPAF facilitates expression of Y-linked male fertility factor genes and thus serves to maintain spermatocyte-specific gene expression. Consistently, tPAF is required for the segregation of meiotic chromosomes and male fertility. Supported by comparative in vivo protein interaction assays, we provide a mechanistic model for the functional divergence of tPAF and the PAF1C and identify transcription termination as a developmentally regulated process required for germline-specific gene expression.




on

A cellular identity crisis? Plasticity changes during aging and rejuvenation [Reviews]

Cellular plasticity in adult multicellular organisms is a protective mechanism that allows certain tissues to regenerate in response to injury. Considering that aging involves exposure to repeated injuries over a lifetime, it is conceivable that cell identity itself is more malleable—and potentially erroneous—with age. In this review, we summarize and critically discuss the available evidence that cells undergo age-related shifts in identity, with an emphasis on those that contribute to age-associated pathologies, including neurodegeneration and cancer. Specifically, we focus on reported instances of programs associated with dedifferentiation, biased differentiation, acquisition of features from alternative lineages, and entry into a preneoplastic state. As some of the most promising approaches to rejuvenate cells reportedly also elicit transient changes to cell identity, we further discuss whether cell state change and rejuvenation can be uncoupled to yield more tractable therapeutic strategies.




on

Harnessing brain-body communication to understand cancer [Special Section: Symposium Outlook]

Solid tumors that arise in the body interact with neurons, which influences cancer progression and treatment response. Here, we discuss key questions in the field, including defining the nature of interactions between tumors and neural circuits and defining how neural signals shape the tumor microenvironment. This information will allow us to optimally target neural signaling to improve outcomes for cancer patients.




on

Temperature matters: the potential impact of thermoregulatory mechanisms in brain-body physiology [Special Section: Symposium Outlook]

Thermoregulation, responsible for maintaining a stable core temperature during wide fluctuations in external and internal thermal environments, is an iconic homeostatic process. However, we suggest that despite its fundamental physiological significance, the potential for required cool housing temperatures and thermoregulatory mechanisms to influence the interpretation of experimental data is not sufficiently appreciated. Moreover, although it is generally assumed that the major thermoregulatory pathways are well understood, here we discuss new research that suggests otherwise and reveals the emergence of a new wave of exciting ideas for this "old" field of research.




on

Bridging brain and body in cancer [Special Section: Symposium Outlook]

Recent work has highlighted the central role the brain–body axis plays in not only maintaining organismal homeostasis but also coordinating the body's response to immune and inflammatory insults. Here, we discuss how science is poised to address the many ways that our brain is directly involved with disease. In particular, we feel that combining cutting-edge tools in neuroscience with translationally relevant models of cancer will be critical to understanding how the brain and tumors communicate and modulate each other's behavior.




on

Interoceptive inference and prediction in food-related disorders [Special Section: Symposium Outlook]

The brain's capacity to predict and anticipate changes in internal and external environments is fundamental to initiating efficient adaptive responses, behaviors, and reflexes that minimize disruptions to physiology. In the context of feeding control, the brain predicts and anticipates responses to the consumption of dietary substances, thus driving adaptive behaviors in the form of food choices, physiological preparation for meals, and engagement of defensive mechanisms. Here, we provide an integrative perspective on the multisensory computation between exteroceptive and interoceptive cues that guides feeding strategy and may result in food-related disorders.




on

Consolidating roles of neuroimmune reflexes: specificity of afferent, central, and efferent signals in homeostatic immune networks [Special Section: Symposium Outlook]

Neural reflexes occupy a central role in physiological homeostasis. The vagus nerve is a major conduit for transmitting afferent and efferent signals in homeostatic reflex arcs between the body and the brain. Recent advances in neuroscience, immunology, and physiology have revealed important vagus nerve mechanisms in suppressing inflammation and treating rheumatoid arthritis and other autoimmune conditions. Numerous clinical trials indicate that there is significant benefit to vagus nerve stimulation therapy. Although many questions are still unanswered, it will be important, even necessary, to pursue answers that will be useful in guiding interventions to modulate immunological and physiological homeostasis.




on

What a wonderful world! [Special Section: Symposium Outlook]

The world of cancer science is moving toward a paradigm shift in making connections with neuroscience. After decades of research on genetic instability and mutations or on the tumor microenvironment, emerging evidence suggests that a malignant tumor is able to hijack and use the brain and its network of peripheral and central neurons as disrupters of homeostasis in the body. Whole-body homeostasis requires brain–body circuits to maintain survival and health via the processes of interoception, immunoception, and nociception. It is now likely that cancer disturbs physiological brain–body communication in making bidirectional brain tumor connections.




on

Deciphering visceral instincts: a scientific quest to unravel food choices from molecules to mind [Special Section: Symposium Outlook]

The study of biological mechanisms, while crucial, cannot fully explain complex phenomena like the instinct to eat. The mind–body connection, as exemplified by the concept of "voodoo death," highlights the profound influence of belief and cultural context on physiology. Indigenous knowledge systems further emphasize the interconnectedness of humans with their environment. Recent discoveries in gut–brain communication reveal the intricate neural circuits that drive our visceral desires, but a holistic approach that integrates both physiological mechanisms and the subjective experience of life, informed by diverse cultural perspectives, will be essential to truly understand what it means to be alive.




on

The area postrema: a critical mediator of brain-body interactions [Special Section: Symposium Outlook]

The dorsal vagal complex contains three structures: the area postrema, the nucleus tractus solitarii, and the dorsal motor nucleus of the vagus. These structures are tightly linked, both anatomically and functionally, and have important yet distinct roles in not only conveying peripheral bodily signals to the rest of the brain but in the generation of behavioral and physiological responses. Reports on the new discoveries in these structures were highlights of the symposium. In this outlook, we focus on the roles of the area postrema in mediating brain–body interactions and its potential utility as a therapeutic target, especially in cancer cachexia.




on

Cancer neuroscience at the brain-body interface [Special Section: Symposium Outlook]

Our approaches toward understanding cancer have evolved beyond cell-intrinsic and local microenvironmental changes within the tumor to encompass how the cancer interfaces with the entire host organism. The nervous system is uniquely situated at the interface between the brain and body, constantly receiving and sending signals back and forth to maintain homeostasis and respond to salient stimuli. It is becoming clear that various cancers disrupt this dialog between the brain and body via both neuronal and humoral routes, leading to aberrant brain activity and accelerated disease. In this outlook, I discuss this view of cancer as a homeostatic challenge, emphasize cutting-edge work, and provide outstanding questions that need to be answered to move the field forward.




on

Dysregulating mTORC1-4E-BP2 signaling in GABAergic interneurons impairs hippocampus-dependent learning and memory [RESEARCH PAPERS]

Memory formation is contingent on molecular and structural changes in neurons in response to learning stimuli—a process known as neuronal plasticity. The initiation step of mRNA translation is a gatekeeper of long-term memory by controlling the production of plasticity-related proteins in the brain. The mechanistic target of rapamycin complex 1 (mTORC1) controls mRNA translation, mainly through phosphorylation of the eukaryotic initiation factor 4E (eIF4E)-binding proteins (4E-BPs) and ribosomal protein S6 kinases (S6Ks). mTORC1 signaling decreases throughout brain development, starting from the early postnatal period. Here, we discovered that in mice, the age-dependent decrease in mTORC1 signaling occurs selectively in excitatory but not inhibitory neurons. Using a gene conditional knockout (cKO) strategy, we demonstrate that either up- or downregulating the mTORC1-4E-BP2 axis in GAD65 inhibitory interneurons, but not excitatory neurons, results in long-term object recognition and object location memory deficits. Our data indicate that the mTORC1 pathway in inhibitory but not excitatory neurons plays a key role in memory formation.




on

The influence of categorical stimuli on relational memory binding [RESEARCH PAPERS]

Binding of arbitrary information into distinct memory representations that can be used to guide behavior is a hallmark of relational memory. What is and is not bound into a memory representation and how those things influence the organization of that representation remain topics of interest. While some information is intentionally and effortfully bound—often the information that is consistent with task goals or expectations about what information may be required later—other information appears to be bound automatically. The present set of experiments sought to investigate whether spatial memory would be systematically influenced by the presence and absence of distinct categories of stimuli on a spatial reconstruction task. In this task, participants must learn multiple item-location bindings and place each item back in its studied location after a short delay. Across three experiments, participants made significantly more within-category errors (i.e., misassigning one item to the location of a different item from the same category) than between-category errors (i.e., misassigning one item to the location of an item from a different category) when categories were perceptually or semantically distinct. These data reveal that category information contributed to the organization of the memory representation and influenced spatial reconstruction performance. Together, these results suggest that categorical information can influence memory organization, and not always to the benefit of overall task performance.




on

High-resolution reconstruction of a C. elegans ribosome sheds light on evolutionary dynamics and tissue specificity [ARTICLE]

Caenorhabditis elegans is an important model organism for human health and disease, with foundational contributions to the understanding of gene expression and tissue patterning in animals. An invaluable tool in modern gene expression research is the presence of a high-resolution ribosome structure, though no such structure exists for C. elegans. Here, we present a high-resolution single-particle cryogenic electron microscopy (cryo-EM) reconstruction and molecular model of a C. elegans ribosome, revealing a significantly streamlined animal ribosome. Many facets of ribosome structure are conserved in C. elegans, including overall ribosomal architecture and the mechanism of cycloheximide, whereas other facets, such as expansion segments and eL28, are rapidly evolving. We identify uL5 and uL23 as two instances of tissue-specific ribosomal protein paralog expression conserved in Caenorhabditis, suggesting that C. elegans ribosomes vary across tissues. The C. elegans ribosome structure will provide a basis for future structural, biochemical, and genetic studies of translation in this important animal system.




on

Characterization and implementation of the MarathonRT template-switching reaction to expand the capabilities of RNA-seq [ARTICLE]

End-to-end RNA-sequencing methods that capture 5'-sequence content without cumbersome library manipulations are of great interest, particularly for analysis of long RNAs. While template-switching methods have been developed for RNA sequencing by distributive short-read RTs, such as the MMLV RTs used in SMART-Seq methods, they have not been adapted to leverage the power of ultraprocessive RTs, such as those derived from group II introns. To facilitate this transition, we dissected the individual processes that guide the enzymatic specificity and efficiency of the multistep template-switching reaction carried out by RTs, in this case, by MarathonRT. Remarkably, this is the first study of its kind, for any RT. First, we characterized the nucleotide specificity of nontemplated addition (NTA) reaction that occurs when the RT extends past the RNA 5'-terminus. We then evaluated the binding specificity of specialized template-switching oligonucleotides, optimizing their sequences and chemical properties to guide efficient template-switching reaction. Having dissected and optimized these individual steps, we then unified them into a procedure for performing RNA sequencing with MarathonRT enzymes, using a well-characterized RNA reference set. The resulting reads span a six-log range in transcript concentration and accurately represent the input RNA identities in both length and composition. We also performed RNA-seq from total human RNA and poly(A)-enriched RNA, with short- and long-read sequencing demonstrating that MarathonRT enhances the discovery of unseen RNA molecules by conventional RT. Altogether, we have generated a new pipeline for rapid, accurate sequencing of complex RNA libraries containing mixtures of long RNA transcripts.




on

lncRNA BC200 is processed into a stable Alu monomer [ARTICLE]

The noncoding RNA BC200 is elevated in human cancers and is implicated in translation regulation as well as cell survival and proliferation. Upon BC200 overexpression, we observed correlated expression of a second, smaller RNA species. This RNA is expressed endogenously and exhibits cell-type-dependent variability relative to BC200. Aptamer-tagged expression constructs confirmed that the RNA is a truncated form of BC200, and sequencing revealed a modal length of 120 nt; thus, we refer to the RNA fragment as BC120. We present a methodology for accurate and specific detection of BC120 and establish that BC120 is expressed in several normal human tissues and is also elevated in ovarian cancer. BC120 exhibits remarkable stability relative to BC200 and is resistant to knockdown strategies that target the 3' unique sequence of BC200. Combined knockdown of BC200 and BC120 exhibits greater phenotypic impacts than knockdown of BC200 alone, and overexpression of BC120 negatively impacts translation of a GFP reporter, providing insight into a potential translational regulatory role for this RNA. The presence of a novel, truncated, and stable form of BC200 adds complexity to the investigation of this noncoding RNA that must be considered in future studies of BC200 and other related Alu RNAs.




on

The small noncoding RNA Vaultrc5 is dispensable to mouse development [ARTICLE]

Vault RNAs (vtRNAs) are evolutionarily conserved small noncoding RNAs transcribed by RNA polymerase III. Vault RNAs were initially described as components of the vault particle, but have since been assigned multiple vault-independent functions, including regulation of PKR activity, apoptosis, autophagy, lysosome biogenesis, and viral particle trafficking. The full-length transcript has also been described as a noncanonical source of miRNAs, which are processed in a DICER-dependent manner. As central molecules in vault-dependent and independent processes, vtRNAs have been attributed numerous biological roles, including regulation of cell proliferation and survival, response to viral infections, drug resistance, and animal development. Yet, their impact to mammalian physiology remains largely unexplored. To study vault RNAs in vivo, we generated a mouse line with a conditional Vaultrc5 loss-of-function allele. Because Vaultrc5 is the sole murine vtRNA, this allele enables the characterization of the physiological requirements of this conserved class of small regulatory RNAs in mammals. Using this strain, we show that mice constitutively null for Vaultrc5 are viable and histologically normal but have a slight reduction in platelet counts, pointing to a potential role for vtRNAs in hematopoiesis. This work paves the way for further in vivo characterizations of this abundant but mysterious RNA molecule. Specifically, it enables the study of the biological consequences of constitutive or lineage-specific Vaultrc5 deletion and of the physiological requirements for an intact Vaultrc5 during normal hematopoiesis or in response to cellular stresses such as oncogene expression, viral infection, or drug treatment.




on

The antivirulent Staphylococcal sRNA SprC regulates CzrB efflux pump to adapt its response to zinc toxicity [ARTICLE]

Bacterial regulatory RNAs (sRNAs) are important players to control gene expression. In Staphylococcus aureus, SprC is an antivirulent trans-acting sRNA known to base-pair with the major autolysin atl mRNA, preventing its translation. Using MS2-affinity purification coupled with RNA sequencing, we looked for its sRNA-RNA interactome and identified 14 novel mRNA targets. In vitro biochemical investigations revealed that SprC binds two of them, czrB and deoD, and uses a single accessible region to regulate its targets, including Atl translation. Unlike Atl regulation, the characterization of the SprC-czrB interaction pinpointed a destabilization of the czrAB cotranscript, leading to a decrease of the mRNA level that impaired CzrB zinc efflux pump expression. On a physiological standpoint, we showed that SprC expression is detrimental to combat against zinc toxicity. In addition, phagocyctosis assays revealed a significant, but moderate, increase of czrB mRNA levels in a sprC-deleted mutant, indicating a functional link between SprC and czrB upon internalization in macrophages, and suggesting a role in resistance to both oxidative and zinc bursts. Altogether, our data uncover a novel pathway in which SprC is implicated, highlighting the multiple strategies used by S. aureus to balance virulence using an RNA regulator.




on

Abolished frameshifting for predicted structure-stabilizing SARS-CoV-2 mutants: implications to alternative conformations and their statistical structural analyses [ARTICLE]

The SARS-CoV-2 frameshifting element (FSE) has been intensely studied and explored as a therapeutic target for coronavirus diseases, including COVID-19. Besides the intriguing virology, this small RNA is known to adopt many length-dependent conformations, as verified by multiple experimental and computational approaches. However, the role these alternative conformations play in the frameshifting mechanism and how to quantify this structural abundance has been an ongoing challenge. Here, we show by DMS and dual-luciferase functional assays that previously predicted FSE mutants (using the RAG graph theory approach) suppress structural transitions and abolish frameshifting. Furthermore, correlated mutation analysis of DMS data by three programs (DREEM, DRACO, and DANCE-MaP) reveals important differences in their estimation of specific RNA conformations, suggesting caution in the interpretation of such complex conformational landscapes. Overall, the abolished frameshifting in three different mutants confirms that all alternative conformations play a role in the pathways of ribosomal transition.




on

DNAJA2 and Hero11 mediate similar conformational extension and aggregation suppression of TDP-43 [REPORT]

Many RNA-binding proteins (RBPs) contain low-complexity domains (LCDs) with prion-like compositions. These long intrinsically disordered regions regulate their solubility, contributing to their physiological roles in RNA processing and organization. However, this also makes these RBPs prone to pathological misfolding and aggregation that are characteristic of neurodegenerative diseases. For example, TAR DNA-binding protein 43 (TDP-43) forms pathological aggregates associated with amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). While molecular chaperones are well-known suppressors of these aberrant events, we recently reported that highly disordered, hydrophilic, and charged heat-resistant obscure (Hero) proteins may have similar effects. Specifically, Hero proteins can maintain the activity of other proteins from denaturing conditions in vitro, while their overexpression can suppress cellular aggregation and toxicity associated with aggregation-prone proteins. However, it is unclear how these protective effects are achieved. Here, we used single-molecule FRET to monitor the conformations of the aggregation-prone prion-like LCD of TDP-43. While we observed high conformational heterogeneity in wild-type LCD, the ALS-associated mutation A315T promoted collapsed conformations. In contrast, an Hsp40 chaperone, DNAJA2, and a Hero protein, Hero11, stabilized extended states of the LCD, consistent with their ability to suppress the aggregation of TDP-43. Our results link single-molecule effects on conformation to macro effects on bulk aggregation, where a Hero protein, like a chaperone, can maintain the conformational integrity of a client protein to prevent its aggregation.