Blood Glucose During High Altitude Trekking in Young Healthy Adults.

Reid, Ly-Anh, Jordan L Rees, Miranda Kimber, Marina James, Graeme M Purdy, Megan Smorschok, Lauren E Maier, Normand G. Boulé, Trevor A. Day, Margie H. Davenport, and Craig D. Steinback. Blood glucose during high altitude trekking in young healthy adults. High Alt Med Biol. 00:00-00, 2024. Introduction: High altitude trekking is becoming more popular and accessible to an increased number of people. Simultaneously, there is a worldwide rise in the prevalence of metabolic diseases. The purpose of this study was to examine the impact of a gradual trekking ascent to high altitude on continuous glucose monitoring outcomes including fasting, mean 24-hour, postprandial, and post-75 g modified oral glucose tolerance test. This study also investigated the relationship between physical activity intensity, high altitude, and glucose concentrations. Methods: Individuals (n = 9) from Alberta, Canada participated in a 2-week trek in the Khumbu Valley in Nepal, ascending by foot from 2,860 m to 5,300 m (∼65 km) over 10 days. A standardized 75 g oral glucose load was given to participants at four different altitudes (1,130 m, 3,440 m, 3,820 m, 5,160 m). Physical activity (Actigraph accelerometry) and interstitial glucose (iPro2, Medtronic) were measured continuously during the trek. Results: Fasting and mean 24-hour glucose concentrations were not different between altitudes. However, 2-hour post dinner glucose and 2-hour post lunch glucose, AUC concentrations were different between altitudes. The relationship between physical activity intensity and glucose was not influenced by increasing altitudes. Conclusion: Our findings suggest that glucose regulation is largely preserved at high altitude; however, inconsistency in our postprandial glucose concentrations at altitude warrants further investigation.

Changes in Emergency Department Pediatric Readiness and Mortality.

Importance: High emergency department (ED) pediatric readiness is associated with improved survival, but the impact of changes to ED readiness is unknown. Objective: To evaluate the association of changes in ED pediatric readiness at US trauma centers between 2013 and 2021 with pediatric mortality. Design, Setting, and Participants: This retrospective cohort study was performed from January 1, 2012, through December 31, 2021, at EDs of trauma centers in 48 states and the District of Columbia. Participants included injured children younger than 18 years with admission or injury-related death at a participating trauma center, including transfers to other trauma centers. Data analysis was performed from May 2023 to January 2024. Exposure: Change in ED pediatric readiness, measured using the weighted Pediatric Readiness Score (wPRS, range 0-100, with higher scores denoting greater readiness) from national assessments in 2013 and 2021. Change groups included high-high (wPRS ≥93 on both assessments), low-high (wPRS <93 in 2013 and wPRS ≥93 in 2021), high-low (wPRS ≥93 in 2013 and wPRS <93 in 2021), and low-low (wPRS <93 on both assessments). Main Outcomes and Measures: The primary outcome was lives saved vs lost, according to ED and in-hospital mortality. The risk-adjusted association between changes in ED readiness and mortality was evaluated using a hierarchical, mixed-effects logistic regression model based on a standardized risk-adjustment model for trauma, with a random slope-random intercept to account for clustering by the initial ED. Results: The primary sample included 467 932 children (300 024 boys [64.1%]; median [IQR] age, 10 [4 to 15] years; median [IQR] Injury Severity Score, 4 [4 to 15]) at 417 trauma centers. Observed mortality by ED readiness change group was 3838 deaths of 144 136 children (2.7%) in the low-low ED group, 1804 deaths of 103 767 children (1.7%) in the high-low ED group, 1288 deaths of 64 544 children (2.0%) in the low-high ED group, and 2614 deaths of 155 485 children (1.7%) in the high-high ED group. After risk adjustment, high-readiness EDs (persistent or change to) had 643 additional lives saved (95% CI, -328 to 1599 additional lives saved). Low-readiness EDs (persistent or change to) had 729 additional preventable deaths (95% CI, -373 to 1831 preventable deaths). Secondary analysis suggested that a threshold of wPRS 90 or higher may optimize the number of lives saved. Among 716 trauma centers that took both assessments, the median (IQR) wPRS decreased from 81 (63 to 94) in 2013 to 77 (64 to 93) in 2021 because of reductions in care coordination and quality improvement. Conclusions and Relevance: Although the findings of this study of injured children in US trauma centers were not statistically significant, they suggest that trauma centers should increase their level of ED pediatric readiness to reduce mortality and increase the number of pediatric lives saved after injury.

Adapting the Zero Suicide framework to the adult emergency department setting: Strategies for nurse leaders.

The ED has been increasingly recognized as a key setting for suicide prevention. Zero Suicide (ZS) is an aspirational goal to eliminate suicide for all patients within a health care system through utilization of best practices. However, there has been limited exploration of ZS implementation within the ED. As ED nurses play an important role in suicide prevention through their close contact with patients at risk for suicide, ZS implementation would benefit from tailored strategies for ED nurse leadership. We describe the ZS framework and provides strategies for nurse leaders to adapt each ZS component in the adult ED.

Multidecadal vegetation transformations of a New Mexico ponderosa pine landscape after severe fires and aerial seeding.

Wildfires and climate change increasingly are transforming vegetation composition and structure, and postfire management may have long-lasting effects on ecosystem reorganization. Postfire aerial seeding treatments are commonly used to reduce runoff and soil erosion, but little is known about how seeding treatments affect native vegetation recovery over long periods of time, particularly in type-converted forests that have been dramatically transformed by the effects of repeated, high-severity fire. In this study, we analyze and report on a rare long-term (23-year) dataset that documents vegetation dynamics following a 1996 post-fire aerial seeding treatment and a subsequent 2011 high-severity reburn in a dry conifer landscape of northern New Mexico, USA. Repeated surveys between 1997 and 2019 of 49 permanent transects were analyzed for differences in vegetation cover, richness, and diversity between seeded and unseeded areas, and to characterize the development of seeded and unseeded vegetation communities through time and across gradients of burn severity, elevation, and soil-available water capacity. Seeded plots showed no significant difference in bare ground cover during the initial years postfire relative to unseeded plots. Postfire seeding led to a clear and sustained divergence in herbaceous community composition. Seeded plots had a much higher cover of non-native graminoids, primarily Bromus inermis, a likely contaminant in the seed mix. High-severity reburning of all plots in 2011 reduced native graminoid cover by half at seeded plots compared with both prefire levels and with plots that were unseeded following the initial 1996 fire. In addition, higher fire severity was associated with increased non-native graminoid cover and reduced native graminoid cover. This study documents fire-driven ecosystem transformation from conifer forest into a shrub-and-grass-dominated system, reinforced by aerial seeding of grasses and high-severity reburning. This unique long-term dataset illustrates that post-fire seeding carries significant risks of unwanted non-native species invasions that persist through subsequent fires-thus alternative postfire management actions merit consideration to better support native ecosystem resilience given emergent climate change and increasing disturbance. This study also highlights the importance of long-term monitoring of postfire vegetation dynamics, as short-term assessments miss key elements of complex ecosystem responses to fire and postfire management actions.

Allometry and ecology shape eye size evolution in spiders.

Eye size affects many aspects of visual function, but eyes are costly to grow and maintain. The allometry of eyes can provide insight into this trade-off, but this has mainly been explored in species that have two eyes of equal size. By contrast, animals possessing larger visual systems can exhibit variable eye sizes within individuals. Spiders have up to four pairs of eyes whose sizes vary dramatically, but their ontogenetic, static, and evolutionary allometry has not yet been studied in a comparative context. We report variable dynamics in eye size across 1,098 individuals in 39 species and 8 families, indicating selective pressures and constraints driving the evolution of different eye pairs and lineages. Supplementing our sampling with a recently published phylogenetically comprehensive dataset, we confirmed these findings across more than 400 species; found that ecological factors such as visual hunting, web building, and circadian activity correlate with eye diameter; and identified significant allometric shifts across spider phylogeny using an unbiased approach, many of which coincide with visual hunting strategies. The modular nature of the spider visual system provides additional degrees of freedom and is apparent in the strong correlations between maximum/minimum investment and interocular variance and three key ecological factors. Our analyses suggest an antagonistic relationship between the anterior and posterior eye pairs. These findings shed light on the relationship between spider visual systems and their diverse ecologies and how spiders exploit their modular visual systems to balance selective pressures and optical and energetic constraints.

Comparative Trends in the Distribution of Prostate Cancer Stage at Diagnosis in the Department of Defense Cancer Registry and the Surveillance, Epidemiology, and End Results Data, 2004-2014.

INTRODUCTION: It has been demonstrated that there was an increase in later-stage prostate cancer (PCa) at diagnosis after the U.S. Preventive Services Task Force recommended against prostate-specific antigen screening for prostate cancer. However, the cancer characteristics at diagnosis within the equal-access Military Health System (MHS) during the period have not been described. In this study, we compared PCa stage at diagnosis and its trends between the military health care system and the general public and further compared the trends in tumor stage by race. MATERIALS AND METHODS: This study was based on nonidentifiable data from the U.S. Department of Defense's Central Cancer Registry (CCR) and the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute. Patients diagnosed between 2004 and 2014 were included. The distributions of PCa stage at diagnosis over time were compared between the 2 populations. Comparisons were further conducted for White and Black patients, respectively. RESULTS: Among the 11,895 patients in the CCR and 544,142 patients in SEER, the majority of patients were diagnosed with stage I or II prostate cancer. However, the CCR had a larger proportion of early-stage tumors (stages I and II combined) with 84.3% vs. 80.0% of SEER patients. The proportion of late-stage tumors (stages III and IV combined) increased over time from 2008 for both populations and the proportion of early-stage tumors decreased for the general population. In terms of temporal distributions by race, the trends were the same between White and Black groups in the general population. In the MHS, the trends in the White patients were similar to those in the general population, but in the Black patients, the percentages of stages I and II at diagnosis continued to increase and those of stages III and IV decreased, differing from those in the general population. CONCLUSIONS: The MHS consistently diagnosed PCa at an earlier stage than the U.S. general population across all time periods evaluated in this study. Although similar trends were observed for White patients between both populations, the proportion of stages I and II at diagnosis increased from 2012 among Black patients in the MHS, which stands in sharp contrast to trends in the U.S. general population. Although the differences between the two populations may be associated with various factors, differences in accessibility to care and thus the use of prostate-specific antigen testing might play an important role.

Development and external validation of a head and neck cancer risk prediction model.

BACKGROUND: Head and neck cancer (HNC) incidence is on the rise, often diagnosed at late stage and associated with poor prognoses. Risk prediction tools have a potential role in prevention and early detection. METHODS: The IARC-ARCAGE European case-control study was used as the model development dataset. A clinical HNC risk prediction model using behavioral and demographic predictors was developed via multivariable logistic regression analyses. The model was then externally validated in the UK Biobank cohort. Model performance was tested using discrimination and calibration metrics. RESULTS: 1926 HNC cases and 2043 controls were used for the development of the model. The development dataset model including sociodemographic, smoking, and alcohol variables had moderate discrimination, with an area under curve (AUC) value of 0.75 (95% CI, 0.74-0.77); the calibration slope (0.75) and tests were suggestive of good calibration. 384 616 UK Biobank participants (with 1177 HNC cases) were available for external validation of the model. Upon external validation, the model had an AUC of 0.62 (95% CI, 0.61-0.64). CONCLUSION: We developed and externally validated a HNC risk prediction model using the ARCAGE and UK Biobank studies, respectively. This model had moderate performance in the development population and acceptable performance in the validation dataset. Demographics and risk behaviors are strong predictors of HNC, and this model may be a helpful tool in primary dental care settings to promote prevention and determine recall intervals for dental examination. Future addition of HPV serology or genetic factors could further enhance individual risk prediction.

University teaching of mass spectrometry as a key practical technique within the context of a fully integrated, spiral curriculum.

RATIONALE: Mass spectrometry (MS) is introduced to high school students in the UK in many pre-university course syllabi. As such, we have identified the use of MS as a key technique that should be taught practically to undergraduates from the outset of their studies. This mini-review describes how we introduce and develop students' use of MS throughout our three-year undergraduate spiral curriculum practical programme, using atmospheric pressure chemical ionization MS (APCI-MS). METHODS: We have used an Advion ExpressionL spectrometer, fitted with an atmospheric solids analysis probe or a Plate Express TLC sampler for sample introduction. RESULTS: We have successfully demonstrated the use of APCI-MS in a range of practicals and experiments covering organic and organometallic chemistries, with large cohorts of students gaining hands-on instrumental experience in authentic research settings. CONCLUSIONS: APCI-MS has proven to be an easy-to-use and valuable addition to our undergraduate practical course. The robustness of the spectrometer enables routine use by large cohorts of students with minimal supervision, and routine maintenance can be carried out by non-specialist technicians. Students can readily process and interpret results for a series of routine analyses, as well as demonstrate uses in problem-solving exercises.

Influence of hypercapnia and hypercapnic hypoxia on the heart rate response to apnea.

We aimed to determine the relative contribution of hypercapnia and hypoxia to the bradycardic response to apneas. We hypothesized that apneas with hypercapnia would cause greater bradycardia than normoxia, similar to the response seen with hypoxia, and that apneas with hypercapnic hypoxia would induce greater bradycardia than hypoxia or hypercapnia alone. Twenty-six healthy participants (12 females; 23 ± 2 years; BMI 24 ± 3 kg/m2) underwent three gas challenges: hypercapnia (+5 torr end tidal partial pressure of CO2 [PETCO2]), hypoxia (50 torr end tidal partial pressure of O2 [PETO2]), and hypercapnic hypoxia (combined hypercapnia and hypoxia), with each condition interspersed with normocapnic normoxia. Heart rate and rhythm, blood pressure, PETCO2, PETO2, and oxygen saturation were measured continuously. Hypercapnic hypoxic apneas induced larger bradycardia (-19 ± 16 bpm) than normocapnic normoxic apneas (-11 ± 15 bpm; p = 0.002), but had a comparable response to hypoxic (-19 ± 15 bpm; p = 0.999) and hypercapnic apneas (-14 ± 14 bpm; p = 0.059). Hypercapnic apneas were not different from normocapnic normoxic apneas (p = 0.134). After removal of the normocapnic normoxic heart rate response, the change in heart rate during hypercapnic hypoxia (-11 ± 16 bpm) was similar to the summed change during hypercapnia+hypoxia (-9 ± 10 bpm; p = 0.485). Only hypoxia contributed to this bradycardic response. Under apneic conditions, the cardiac response is driven by hypoxia.

A pilot dose-finding study of Terazosin in humans.

Background: Parkinson's disease (PD) is a prevalent neurodegenerative disorder where progressive neuron loss is driven by impaired brain bioenergetics, particularly mitochondrial dysfunction and disrupted cellular respiration. Terazosin (TZ), an α-1 adrenergic receptor antagonist with a known efficacy in treating benign prostatic hypertrophy and hypertension, has shown potential in addressing energy metabolism deficits associated with PD due to its action on phosphoglycerate kinase 1 (PGK1). This study aimed to investigate the safety, tolerability, bioenergetic target engagement, and optimal dose of TZ in neurologically healthy subjects. Methods: Eighteen healthy men and women (60 - 85 years old) were stratified into two cohorts based on maximum TZ dosages (5 mg and 10 mg daily). Methods included plasma and cerebrospinal fluid TZ concentration measurements, whole blood ATP levels, 31 Phosphorous magnetic resonance spectroscopy for brain ATP levels, 18 F-FDG PET imaging for cerebral metabolic activity, and plasma metabolomics. Results: Our results indicated that a 5 mg/day dose of TZ significantly increased whole blood ATP levels and reduced global cerebral 18 F-FDG PET uptake without significant side effects or orthostatic hypotension. These effects were consistent across sexes. Higher doses did not result in additional benefits and showed a potential biphasic dose-response. Conclusions: TZ at a dosage of 5 mg/day engages its metabolic targets effectively in both sexes without inducing significant adverse effects and provides a promising therapeutic avenue for mitigating energetic deficiencies. Further investigation via clinical trials to validate TZ's efficacy and safety in neurodegenerative (i.e., PD) contexts is warranted.

Assessing eDNA capture method from aquatic environment to optimise recovery of human mt-eDNA.

Previous studies have shown that environmental DNA (eDNA) from human sources can be recovered from natural bodies of water, and the generation of DNA profiles from such environmental samples may assist in forensic investigations. However, fundamental knowledge gaps exist around the factors influencing the probability of detecting human eDNA and the design of optimal sampling protocols. One of these is understanding the particle sizes eDNA signals are most strongly associated with and the most appropriate filter size needed for efficiently capturing eDNA particles. This study assessed the amount of mitochondrial eDNA associated with different particle sizes from human blood and skin cells recovered from freshwater samples. Samples (300 mL) were taken from experimental 10 L tanks of freshwater spiked with 50 µL of human blood or skin cells deposited by vigorously rubbing hands together for two minutes in freshwater. Subsamples were collected by passing 250 mL of experimental water sample through six different filter pore sizes (from 0.1 to 8 µm). This process was repeated at four time intervals after spiking over 72 hours to assess if the particle size of the amount of eDNA recovered changes as the eDNA degrades. Using a human-specific quantitative polymerase chain reaction (qPCR) assay targeting the HV1 mitochondrial gene region, the total amount of mitochondrial eDNA associated with different particle size fractions was determined. In the case of human blood, at 0 h, the 0.45 µm filter pore size captured the greatest amount of mitochondrial eDNA, capturing 42 % of the eDNA detected. The pattern then changed after 48 h, with the 5 µm filter pore size capturing the greatest amount of eDNA (67 %), and 81 % of eDNA at 72 h. Notably, a ten-fold dilution proved to be a valuable strategy for enhancing eDNA recovery from the 8 µm filter at all time points, primarily due to the PCR inhibition observed in hemoglobin. For human skin cells, the greatest amounts of eDNA were recovered from the 8 µm filter pore size and were consistent through time (capturing 37 %, 56 %, and 88 % of eDNA at 0 hours, 48 hours, and 72 hours respectively). There is a clear variation in the amount of eDNA recovered between different cell types, and in some forensic scenarios, there is likely to be a mix of cell types present. These results suggest it would be best to use a 5 µm filter pore size to capture human blood and an 8 µm filter pore size to capture human skin cells to maximize DNA recovery from freshwater samples. Depending on the cell type contributing to the eDNA, a combination of different filter pore sizes may be employed to optimize the recovery of human DNA from water samples. This study provides the groundwork for optimizing a strategy for the efficient recovery of human eDNA from aquatic environments, paving the way for its broader application in forensic and environmental sciences.

Pulmonary Hypertension and Survival among Non-Small Cell Lung Cancer Patients: A Retrospective Cohort Study in the U.S. Military Health System.

Background: Lung cancer is one of the most lethal cancers with survival being closely related to stage and influenced by comorbid illness. The survival implications of pulmonary hypertension (PH) on patients with non-small cell lung cancer (NSCLC) have only been evaluated in small cohorts, with limited long-term follow-up. Methods: We conducted a retrospective cohort study of 7946 patients with NSCLC diagnosed in the MHS. This study evaluated the survival impact of PH in patients diagnosed with NSCLC in the MHS. Patients were classified as having and not having PH. We stratified PH into those diagnosed before the diagnosis of NSCLC and those diagnosed after NSCLC diagnosis. Results: Relative to patients without PH, patients with PH diagnosed before NSCLC had an increased risk of death (HR = 1.15 [95% CI, 1.02-1.29]). The increased risk of death was more obvious for patients with PH diagnosed after NSCLC compared with those without PH (HR = 2.74 [95% CI, 2.51-2.99]). The results were similar when stratified by patient demographics. Conclusions: In the MHS, PH is associated with worsened NSCLC survival, regardless of when it is diagnosed. When PH is diagnosed after NSCLC, it is associated with a marked reduction in survival, and this finding may suggest a potential role for monitoring pulmonary pressures in NSCLC patients. Furthermore, as specific PH therapy exists, some NSCLC patients with PH may be candidates for therapy.

Structure of the Hir histone chaperone complex.

The evolutionarily conserved HIRA/Hir histone chaperone complex and ASF1a/Asf1 co-chaperone cooperate to deposit histone (H3/H4)2 tetramers on DNA for replication-independent chromatin assembly. The molecular architecture of the HIRA/Hir complex and its mode of histone deposition have remained unknown. Here, we report the cryo-EM structure of the S. cerevisiae Hir complex with Asf1/H3/H4 at 2.9-6.8 Å resolution. We find that the Hir complex forms an arc-shaped dimer with a Hir1/Hir2/Hir3/Hpc2 stoichiometry of 2/4/2/4. The core of the complex containing two Hir1/Hir2/Hir2 trimers and N-terminal segments of Hir3 forms a central cavity containing two copies of Hpc2, with one engaged by Asf1/H3/H4, in a suitable position to accommodate a histone (H3/H4)2 tetramer, while the C-terminal segments of Hir3 harbor nucleic acid binding activity to wrap DNA around the Hpc2-assisted histone tetramer. The structure suggests a model for how the Hir/Asf1 complex promotes the formation of histone tetramers for their subsequent deposition onto DNA.

The hospital costs of high emergency department pediatric readiness.

Objective: We estimate annual hospital expenditures to achieve high emergency department (ED) pediatric readiness (HPR), that is, weighted Pediatric Readiness Score (wPRS) ≥ 88 (0-100 scale) across EDs with different pediatric volumes of children, overall and after accounting for current levels of readiness. Methods: We calculated the annual hospital costs of HPR based on two components: (1) ED pediatric equipment and supplies and (2) labor costs required for a Pediatric Emergency Care Coordinator (PECC) to perform pediatric readiness tasks. Data sources to generate labor cost estimates included: 2021 national salary information from U.S. Bureau of Labor Statistics, detailed patient and readiness data from 983 EDs in 11 states, the 2021 National Pediatric Readiness Project assessment; a national PECC survey; and a regional PECC survey. Data sources for equipment and supply costs included: purchasing costs from seven healthcare organizations and equipment usage per ED pediatric volume. We excluded costs of day-to-day ED operations (ie, direct clinical care and routine ED supplies). Results: The total annual hospital costs for HPR ranged from $77,712 (95% CI 54,719-100,694) for low volume EDs to $279,134 (95% CI 196,487-362,179) for very high volume EDs; equipment costs accounted for 0.9-5.0% of expenses. The total annual cost-per-patient ranged from $3/child (95% CI 2-4/child) to $222/child (95% CI 156-288/child). After accounting for current readiness levels, the cost to reach HPR ranged from $23,775 among low volume EDs to $145,521 among high volume EDs, with costs per patient of $4/child to $48/child. Conclusions: Annual hospital costs for HPR are modest, particularly when considered per child.

Time-of-Flight MRA of Intracranial Aneurysms with Interval Surveillance, Clinical Segmentation and Annotations.

Intracranial aneurysms (IAs) are present in 2-6% of the global population and can be catastrophic upon rupture with a mortality rate of 30-50%. IAs are commonly detected through time-of-flight magnetic resonance angiography (TOF-MRA), however, this data is rarely available for research and training purposes. The provision of imaging resources such as TOF-MRA images is imperative to develop new strategies for IA detection, rupture prediction, and surgical training. To support efforts in addressing data availability bottlenecks, we provide an open-access TOF-MRA dataset comprising 63 patients, of which 24 underwent interval surveillance imaging by TOF-MRA. Patient scans were evaluated by a neuroradiologist, providing aneurysm and vessel segmentations, clinical annotations, 3D models, in addition to 3D Slicer software environments containing all this data for each patient. This dataset is the first to provide interval surveillance imaging for supporting the understanding of IA growth and stability. This dataset will support computational and experimental research into IA dynamics and assist surgical and radiology training in IA treatment.

Surgical capacity is disaster preparedness: A scoping review of how surgery and anesthesiology departments responded to COVID-19.

OBJECTIVE: This study evaluated how surgical and anesthesiology departments adapted their resources in response to the coronavirus disease 2019 (COVID-19) pandemic. DESIGN: This scoping review used the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews protocol, with Covidence as a screening tool. An initial search of PubMed, Embase, Web of Science, Global Index Medicus, and Cochrane Systematic Reviews returned 6,131 results in October 2021. After exclusion of duplicates and abstract screening, 415 articles were included. After full-text screening, 108 articles remained. RESULTS: Most commonly, studies were retrospective in nature (47.22 percent), with data from a single institution (60.19 percent). Nearly all studies occurred in high-income countries (HICs), 78.70 percent, with no articles from low-income countries. The reported responses to the COVID-19 pandemic involving surgical departments were grouped into seven categories, with multiple responses reported in some articles for a total of 192 responses. The most frequently reported responses were changes to surgical department staffing (29.17 percent) and task-shifting or task-sharing of personnel (25.52 percent). CONCLUSION: Our review reflects the mechanisms by which hospital surgical systems responded to the initial stress of the COVID-19 pandemic and reinforced the many changes to hospital policy that occurred in the pandemic. Healthcare systems with robust surgical systems were better able to cope with the initial stress of the COVID-19 pandemic. The well-resourced health systems of HICs reported rapid and dynamic changes by providers to assist in and ultimately improve the care of patients during the pandemic. Surgical system strengthening will allow health systems to be more resilient and prepared for the next disaster.

Acute exposure to hydrazine reported to four United States regional poison centers: reconsidering a paradigm.

INTRODUCTION: Exposures to hydrazines occur during aeronautic and space operations and pose a potential risk to personnel. Historically, extensive preparatory countermeasures have been taken due to concern for severe toxicity. This study seeks to better understand manifestations of acute occupational exposures to hydrazine to guide recommendations for management. MATERIALS AND METHODS: A retrospective database review of records from four United States regional poison centers was conducted of all human exposures to hydrazine, monomethylhydrazine, or 1,1-dimethylhydrazine over two decades. Following case abstraction, descriptive statistics were performed to characterize demographics, manifestations, treatments, and outcomes. RESULTS: One hundred and thirty-five cases were identified, and most were adult males exposed to inhaled hydrazine propellant vapors. Fifty-seven percent of patients were asymptomatic following exposure; otherwise, common symptoms were dyspnea, throat irritation, cough, ocular irritation, and headache. All patients were evacuated or received decontamination, with a few reports of symptomatic treatments, including oxygen supplementation and salbutamol (albuterol). Patients usually recovered quickly and were released after a brief healthcare facility evaluation or observed locally. No patients developed delayed symptoms. Symptoms of severe toxicity were not observed, and there were no deaths. DISCUSSION: Acute exposures to hydrazines during operations within the aerospace industry appear to be limited primarily to mucosal and mild pulmonary irritation without significant neurologic, hepatic, or hematologic toxicity. These findings are contrary to previously established expectations and may be related to low-level exposures or possibly due to current emergency countermeasures. CONCLUSIONS: Care in occupational hydrazine exposure will focus on evacuation, decontamination, and symptomatic management of chemical irritant properties of hydrazines. It is reasonable to manage mild cases outside of a healthcare facility. Continued endeavors in human space exploration and habitation will increase the risk of these exposures, making it imperative that clinicians be comfortable with the care and management of these patients.

Population density effects on gamete traits and fertilisation dynamics under varying sperm environments in mussels.

Gamete traits can vary widely among species, populations and individuals, influencing fertilisation dynamics and overall reproductive fitness. Sexual selection can play an important role in determining the evolution of gamete traits with local environmental conditions determining the strength and direction of sexual selection. Here, we test for signatures of post-mating selection on gamete traits in relation to population density, and possible interactive effects of population density and sperm concentration on sperm motility and fertilisation rates among natural populations of mussels. Our study shows that males from high-density populations produce smaller sperm compared with males from low-density populations, but we detected no effect of population density on egg size. Our results also reveal that females from low-density populations tended to exhibit lower fertilisation rates across a range of sperm concentrations, although this became less important as sperm concentration increased. Variances in fertilisation success were higher for females than males and the effect of gamete compatibility between males and females increases as sperm concentrations increase. These results suggest that local population density can influence gamete traits and fertilisation dynamics but also highlight the importance of phenotypic plasticity in governing sperm-egg interactions in a highly dynamic selective environment.