Thermotolerance in S. cerevisiae as a model to study extracellular vesicle biology.

The budding yeast Saccharomyces cerevisiae is a proven model organism for elucidating conserved eukaryotic biology, but to date its extracellular vesicle (EV) biology is understudied. Here, we show yeast transmit information through the extracellular medium that increases survival when confronted with heat stress and demonstrate the EV-enriched samples mediate this thermotolerance transfer. These samples contain vesicle-like particles that are exosome-sized and disrupting exosome biogenesis by targeting endosomal sorting complexes required for transport (ESCRT) machinery inhibits thermotolerance transfer. We find that Bro1, the yeast ortholog of the human exosome biomarker ALIX, is present in EV samples, and use Bro1 tagged with green fluorescent protein (GFP) to track EV release and uptake by endocytosis. Proteomics analysis reveals that heat shock protein 70 (HSP70) family proteins are enriched in EV samples that provide thermotolerance. We confirm the presence of the HSP70 ortholog stress-seventy subunit A2 (Ssa2) in EV samples and find that mutant yeast cells lacking SSA2 produce EVs but they fail to transfer thermotolerance. We conclude that Ssa2 within exosomes shared between yeast cells contributes to thermotolerance. Through this work, we advance Saccharomyces cerevisiae as an emerging model organism for elucidating molecular details of eukaryotic EV biology and establish a role for exosomes in heat stress and proteostasis that seems to be evolutionarily conserved.

Interventions associated with survival after prehospital intubation in the deployed combat setting.

INTRODUCTION: Airway compromise is the second leading cause of potentially preventable death on the battlefield. Prehospital airway management is often unavoidable in a kinetic combat environment and expected to increase in future wars where timely evacuation will be unreliable and air superiority not guaranteed. We compared characteristics of survivors to non-survivors among combat casualties undergoing prehospital airway intubation. MATERIALS AND METHODS: We requested all Department of Defense Trauma Registry (DODTR) encounters during 2007-2023 with documentation of any airway intervention or assessment within the first 72-h after injury. We conducted a retrospective cohort study of all casualties with intubation documented in the prehospital setting. We used descriptive and inferential statistical analysis to compare survivors through 7 days post injury versus non-survivors. We constructed 3 multivariable logistic regression models to test for associations between interventions and 7-day survival after adjusting for injury severity score, mechanism of injury, and receipt of sedatives, paralytics, and blood products. RESULTS: There were 1377 of 48,301 patients with documentation of prehospital intubation in a combat setting. Of these, 1028 (75%) survived through 7 days post injury. Higher proportions of survivors received ketamine, paralytic agents, parenteral opioids, and parenteral benzodiazepines; there was no difference in the proportions of survivors versus non-survivors receiving etomidate. The multivariable models consistently demonstrated positive associations between 7-day survival and receipt of non-depolarizing paralytics and opioid analgesics. CONCLUSIONS: We found an association between non-depolarizing paralytic and opioid receipt with 7-day survival among patients undergoing prehospital intubation. The literature would benefit from future multi-center randomized controlled trials to establish optimal pharmacologic strategies for trauma patients undergoing prehospital intubation.

Massive Transfusion Thresholds Associated with Combat Casualty Mortality during Operations in Afghanistan and Iraq: Implications for Role 1 Logistical Support Chains.

INTRODUCTION: Limited literature exists examining outcomes associated with alternative thresholds for massive transfusion outside of the historical definition of 10 units of packed red blood cells (PRBC) in 24 hours. This study reports the predictive accuracy of alternative thresholds for 24-hour mortality and explores implications for Role 1 care supply requirements. METHODS: We conducted a secondary analysis of data from the Department of Defense Trauma Registry (DODTR) spanning encounters from 1 January 2007 through 17 March 2020. We included all casualties who received at least 1 unit of either PRBC or whole blood. We calculated area under the receiver operator curve (AUROC) of blood product quantity received, including both PRBC and whole blood, as a predictor for mortality within 24 hours of arrival to a military treatment facility. We identified optimal predictive thresholds per Youden's index. RESULTS: We identified 28,950 encounters of which 2,608 (9.0%) entailed receipt of at least 1 unit of PRBC or whole blood. Most casualties sustained battle injuries (2,437, 93.4%) with explosives as the most common mechanism (1,900, 72.8%) followed by firearms (609, 23.3%). The AUROC for blood product received within 24 hours was 0.59. The optimal threshold for predicting 24-hour mortality per Youden's Index was 20 units (sensitivity of 34.9% and specificity of 78.6%). The threshold exceeding 90% sensitivity was 2 units; whereas, the threshold exceeding 90% specificity was 33 units. CONCLUSIONS: We identified a wide range of numbers of received blood products associated with short-term mortality based upon prioritization of sensitivity or specificity. This study found only 2 units of blood product received had a 90% sensitivity for predicting 24-hour mortality, highlighting the resource mobilization challenges that confront healthcare providers during resuscitation at the Role 1.

Case Report: Recurrent Acute Macular Neuroretinopathy-Monitoring Recovery with Multimodal Imaging.

SIGNIFICANCE: Acute macular neuroretinopathy (AMN) is a rare, nonprogressive condition affecting the outer retina that can be diagnosed clinically using widely available multimodal imaging techniques. This case report presents an exceedingly rare same-eye recurrence of AMN and describes the characteristic imaging findings of this unique, not fully understood clinical entity. PURPOSE: The following report provides a detailed account of recurrent AMN from 4 hours of symptom onset to 4 months with repeat multimodal imaging captured at different visits. This report also devotes some discussion to the current understanding of its pathophysiology, associations, management, and imaging characteristics. CASE REPORT: A 32-year-old woman with unilateral recurrent AMN was monitored frequently with various multimodal imaging from 4 hours after onset of new scotoma to 4 months. The primary finding in the acute stage was a hyperreflective lesion of the outer nuclear and outer plexiform layers followed by disruption of underlying external limiting membrane, ellipsoid zone, and photoreceptors. This resolved into stable outer nuclear layer thinning and subtle disruption of the deeper layers after 1 week. Fundus photography revealed a red-brown petaloid lesion adjacent to the fovea, and optical coherence tomography angiography revealed subtle decreased perfusion of the choriocapillaris layer throughout follow-up. CONCLUSIONS: Acute macular neuroretinopathy is a rare nonprogressive condition of the outer retina most often affecting otherwise healthy young female individuals and is most associated with recent flu-like illness and oral contraceptives. The underlying mechanism of AMN remains unknown, but modern imaging techniques have elucidated the disease locus to be choroidal and/or deep capillary plexus. It is important for eye care providers to recognize AMN as a clinical entity distinct from other retinal conditions that require different management.

Not Like the Textbook: An Atypical Case of Ectopic Pregnancy.

Ectopic pregnancy is a potentially life-threatening outcome of pregnancy that occurs with the implantation of an embryo outside of the endometrial cavity. Classically considered a "must not miss" diagnosis, ectopic pregnancy is a common emergency department presentation, associated with a symptom triad of amenorrhea, vaginal bleeding, and abdominal pain. However, varied presentations of ectopic pregnancy or lack of typical risk factors can complicate the evaluation and diagnosis of this condition. This case report describes an atypical presentation of ectopic pregnancy after a reported spontaneous abortion, in which the patient was initially discharged with a diagnosis of pelvic inflammatory disease. This case provides an illustration of ectopic pregnancy that presented without classically associated symptoms, and also highlights how anchoring bias and pre-emptive closure, among other cognitive biases, contributed to a missed diagnosis.

Interrater agreement of the HEART score history component: A chart review study.

Study objectives: This study investigated the interrater reliability of the history component of the HEART (history, electrocardiogram, age, risk, troponin) score between physicians in emergency medicine (EM) and internal medicine (IM) at 1 tertiary-care center. Methods: We conducted a retrospective, secondary analysis of 60 encounters selected randomly from a database of 417 patients with chest pain presenting from January to June 2016 to an urban tertiary-care center. A total of 4 raters (1 EM attending, 1 EM resident, 1 IM attending, and 1 IM resident) scored the previously abstracted history data from these encounters.The primary outcome was the interrater agreement of HEART score history components, as measured by kappa coefficient, between EM and IM attending physicians. Secondary outcomes included the agreement between attending and resident physicians, overall agreement, pairwise percent agreement, and differences in scores assigned. Results: The kappa value for the EM attending physician and IM attending physician was 0.33 with 55% agreement. Interrater agreement of the other pairs was substantial between EM attending and resident but was otherwise fair to moderate. Percent agreement between the other pairs ranged from 48.3% to 80%. There was a significant difference in scores assigned and the subgroup in which there was disagreement between the raters demonstrated significantly higher scores by the EM attending and resident when compared to the IM attending. Conclusion: This study demonstrates fair agreement between EM and IM attending physicians in the history component of the HEART score with significantly higher scores by the EM attending physician in cases of disagreement at 1 tertiary-care center.

Descriptive Analysis of Casualties Rapidly Returned to the Fight after Injury: Reverse Triage Implications for Large Scale Combat Operations.

BACKGROUND: During large scale combat operations, rising numbers of casualties will likely outstrip in-theater US military medical hospitalization assets. This highlights the importance of identifying those casualties who can return to the fight in order to minimize further medical resource depletion. We describe specific characteristics of casualties returned to duty without requiring evacuation from theater during recent major combat operations. MATERIALS AND METHODS: We conducted a secondary analysis of previously published data from the Department of Defense Trauma Registry during 01 January 2007 through 17 March 2020. We included all adult US military casualties. We categorized casualties according to documented disposition, namely, return to duty within 72 hours without evacuation from theater, return to duty greater than 72 hours without evacuation from theater, and all other casualties. RESULTS: Of 10,182 adult US military casualties, 3,856 (37.9%) returned to duty within 72 hours without evacuation from theater and 220 (2.2%) returned to duty in greater than 72 hours without evacuation from theater. The cohort that rapidly returned to duty had a lower median injury severity score (2) than casualties returning to duty in greater than 72 hours (4) and those evacuated from theater (11). Notably higher proportions of casualties evacuated from theater sustained injuries to the face, thorax, abdomen, and extremities. Modes of transportation were similar across all three groups, though casualties undergoing evacuation from theater were more likely to undergo air transportation during the spectrum of their medical care. CONCLUSIONS: Most combat casualties returning to duty without evacuation from theater did so within 72 hours of hospitalization. Casualties not requiring evacuation from theater were less likely to sustain injuries to the face, thorax, abdomen, and extremities.

Lactation ketoacidosis induced by breastfeeding while on a ketogenic diet.

Lactation ketoacidosis is a very rare cause of metabolic acidosis in breastfeeding patients. We present a case of a 34-year-old female, 8-weeks postpartum, who was breastfeeding while also on the ketogenic diet. She developed dyspnea, chest pain, nausea, vomiting, and an inability to tolerate oral intake for several days. She presented with a metabolic acidosis with an anion gap of 33, HCO3 of 5.1 mmol/L, venous pH of 7.045, and serum b-hydroxybutyrate of 7.4 mmol/L. She was treated in the emergency department with intravenous normal saline and intravenous dextrose, with prompt transfer to the intensive care unit for treatment with an intravenous sodium bicarbonate drip and an intravenous insulin drip with dextrose. After normalization of laboratory values, she re-developed an elevated anion gap acidosis after breastfeeding in the ICU overnight. She was started on a carbohydrate-rich diet and made a full recovery without reported repeat incidences. We provide a summary of our case, discuss known causes of lactation ketoacidosis, and emphasize the importance of a thorough history and physical. In this case a dietary history was more helpful than a very expensive laboratory and imaging evaluation.

Shallow Water Diving-Associated Alveolar Hemorrhage in an Active Duty Sailor: A Case Report.

Breath-hold diving is a common practice as a part of military dive training. An association between prior lung injury and a propensity for lung barotrauma may have the potential to impact mission readiness for combat divers, Pararescue, Combat Controllers, Army Engineer divers, and various units in Naval Special Warfare and Special Operations. Barotrauma is a common complication of diving, typically occurring at depths greater than 30 m (98.4 ft). Individuals with abnormal lung anatomy or function may be at increased risk of barotrauma at shallower depths than those with healthy lungs, rendering these service members unfit for certain missions. We describe the case of a 25-year-old male, with a remote history of polytrauma and resultant pulmonary pleural adhesions, whose dive training was complicated by lung barotrauma at shallow depths. In missions or training utilizing breath-hold diving, the association with secondary alterations in lung or thoracic anatomy and function may limit which service members can safely participate.

Development of ex situ normothermic reperfusion as an innovative method to assess pancreases after preservation.

Static cold storage (SCS) is the standard method for pancreas preservation prior to transplantation; however, it does not permit organ assessment. Normothermic reperfusion (NR) is utilized clinically for other organs to assess viability. Our aim was to develop NR using normothermic machine perfusion technique to simulate reperfusion at the time of transplantation, enabling evaluation of oxygenated hypothermic machine perfusion (HMPO2) as a newer strategy to optimize pancreas preservation. 13 porcine pancreases procured after circulatory death were divided into 3 groups: 4 pancreases preserved using SCS, and 2 groups preserved by HMPO2 (n = 4 and n = 5, differing by type of preservation solution). Duration of perfusion or cold storage was 6 hours before the 1-hour assessment using NR. Outcome measures were perfusion characteristics, biochemistry and change in tissue water mass as oedema assessment. During NR, the HMPO2 groups demonstrated better perfusion characteristics, normal macroscopic appearances, decreased water mass and one HMPO2 group demonstrated a response to glucose stimulation. Conversely, the SCS group showed an increased water mass and developed early macroscopic appearances of oedema, interstitial haemorrhage and minimal portal outflow. This study suggests that ex situ assessment of pancreases by NR is promising, and that HMPO2 may be better than SCS.

Peri-intubation cardiac arrest in the Emergency Department: A National Emergency Airway Registry (NEAR) study.

AIM: To determine the incidence of peri-intubation cardiac arrest through analysis of a multi-center Emergency Department (ED) airway registry and to report associated clinical characteristics. METHODS: This is a secondary analysis of prospectively collected data (National Emergency Airway Registry) comprising ED endotracheal intubations (ETIs) of subjects >14 years old from 2016 to 2018. We excluded those with cardiac arrest prior to intubation. The primary outcome was peri-intubation cardiac arrest. Multivariable logistic regression generated adjusted odds ratios (aOR) of variables associated with this outcome, controlling for clinical features, difficult airway characteristics, and ETI modality. RESULTS: Of 15,776 subjects who met selection criteria, 157 (1.0%, 95% CI 0.9-1.2%) experienced peri-intubation cardiac arrest. Pre-intubation systolic blood pressure <100 mm Hg (aOR 6.2, 95% CI 2.5-8.5), pre-intubation oxygen saturation <90% (aOR 3.1, 95% CI 2.0-4.8), and clinician-reported need for immediate intubation without time for full preparation (aOR 1.8, 95% CI, 1.2-2.7) were associated with higher likelihood of peri-intubation cardiac arrest. The association between pre-intubation shock and cardiac arrest persisted in additional modeling stratified by ETI indication, induction agent, and oxygenation status. CONCLUSIONS: Peri-intubation cardiac arrest for patients undergoing ETI in the ED is rare. Higher likelihood of arrest occurs in patients with pre-intubation shock or hypoxemia. Prospective trials are necessary to determine whether a protocol to optimize pre-intubation haemodynamics and oxygenation mitigates the risk of peri-intubation cardiac arrest.

The Biology of Vasopressin.

Vasopressins are evolutionarily conserved peptide hormones. Mammalian vasopressin functions systemically as an antidiuretic and regulator of blood and cardiac flow essential for adapting to terrestrial environments. Moreover, vasopressin acts centrally as a neurohormone involved in social and parental behavior and stress response. Vasopressin synthesis in several cell types, storage in intracellular vesicles, and release in response to physiological stimuli are highly regulated and mediated by three distinct G protein coupled receptors. Other receptors may bind or cross-bind vasopressin. Vasopressin is regulated spatially and temporally through transcriptional and post-transcriptional mechanisms, sex, tissue, and cell-specific receptor expression. Anomalies of vasopressin signaling have been observed in polycystic kidney disease, chronic heart failure, and neuropsychiatric conditions. Growing knowledge of the central biological roles of vasopressin has enabled pharmacological advances to treat these conditions by targeting defective systemic or central pathways utilizing specific agonists and antagonists.

Retropharyngeal Abscess With Severe Airway Compromise Following Anterior Cervical Spine Surgery: A Case Report.

Anterior cervical corpectomy, discectomy, and fusion are common surgical management options for symptomatic cervical radiculopathy and myelopathy. While these procedures are common and well-tolerated, postoperative complications span from mild dysphasia to airway compromise secondary to retropharyngeal or peri-cervical space abscess. These critical patients require robust airway management, which may entail a multidisciplinary approach or airway management in the operating room. We describe a patient who developed airway compromise 10 days following anterior cervical discectomy and fusion with a pre-platysmal abscess and a large retropharyngeal abscess. These abscesses were large enough to cause a mass effect with tracheal deviation. This deviation was severe enough that the patient required awake incision and drainage prior to rapid sequence intubation.

Guanfacine toxic ingestion with subsequent cardiogenic pulmonary edema.

Guanfacine is a central alpha-2 agonist often prescribed for Attention-deficit hyperactive disorder as well as tic disorder, with a usual dose of 1-4 mg per day. Due to its sympatholytic mechanism of action, Guanfacine can cause autonomic instability and hypotension. It can additionally cause cardiac dysfunction to include symptomatic bradycardias and contractility suppression. The authors present a case of a 17 year-old male with an ingestion of 80 mg of extended release Guanfacine with delayed onset cardiogenic pulmonary edema requiring mechanical ventilation. Previous pediatric ingestions have generated bradycardia, hypotension, and decreased level of consciousness, responsive to intravenous fluids, vasopressors, and occasionally naloxone. However, cardiogenic pulmonary edema from reduced cardiac contractility is a novel consequence of extended release Guanfacine ingestion. With Guanfacine's extended half-life, this unique case underscores the importance of emergency providers' familiarity with this toxidrome as well the necessity for prolonged, close observation following Guanfacine ingestion.

Acute coronary syndrome in Dextrocardia.

Situs inversus with dextrocardia is both a clinical and diagnostic challenge for emergency physicians to properly identify acute coronary syndrome. While dextrocardia itself does not independently increase the risk of coronary artery disease, mirrored symptoms, including right-sided and rightward radiating chest pain in any patient with cardiac risk factors should raise suspicion for acute coronary syndrome. In patients with a reversed cardiac silhouette on a chest radiograph, a reversed electrocardiogram, to include both the precordial and limb leads, is necessary to evaluate for cardiac ischemia in presumed dextrocardia. The authors present a case of a 66-year-old man with dextrocardia who presented with shortness of breath and hypotension. Rapid application of a reversed electrocardiogram resulted in the timely diagnosis of ST-segment elevation myocardial infarction and activation of the cardiac catheterization laboratory resulting in the preservation of this patient's life.

A coronavirus disease 2019 (COVID-19) patient with bilateral orchitis.

During the development of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2), a myriad of complications has emerged and although rare, several genitourinary complications have been reported. The bulk of these complications have been secondary to hypercoagulable states, such as priapism. Previous SARS family infections have caused orchitis, though no adult cases of orchitis have been reported. We describe a novel case of SARS-CoV2 bilateral orchitis in a previously healthy 37-year-old male who presented for testicular pain with constitutional symptoms. Additionally, there was no epididymitis associated with the bilateral orchitis. Based on both data in SARS-CoV2 infected males and previous data from prior SARS infections, spermatocyte function may be compromised secondary to this infection. With the various symptoms associated with this virulent pathogen, we characterize the potential complications and importance of fertility follow up.

Pancreaticopleural fistula, a rare mediastinal emergency.

A pancreaticopleural fistula (PPF) is a rare condition that causes thoracic symptoms such as dyspnea and chest pain secondary to exudative pleural effusions. While PPF is a very rare complication with only 52 cases reported between 1960 and 2007, they typically occur in patients who are male, middle aged, and have a history of chronic alcohol use and chronic pancreatitis (Aswani and Hira, 2015; Francisco et al., n.d.; Valeshabad et al., 2018; Ali et al., 2009). The fistula between the pancreas and pleural cavity causes large, rapidly accumulating, and recurrent pleural effusions which cause symptoms that can be difficult to differentiate from other acute thoracic pathologies (Francisco et al., n.d.). As a result, it is essential that providers have a high index of suspicion for PPF in these appropriate populations. We present a case study to review the typical presentation, pathophysiology, and current approach to treatment of PPF. This case is unique as the patient had no known risk factors. Due to limited data on this topic, there are no evidence-based guidelines on this topic, leaving a variety of case reports to inform clinical management in the emergency department.

Postpartum Bilateral Subdural Hematomas: A Case Report.

Postpartum headache is a common emergency department (ED) complaint in women following delivery. Though the majority of these headaches are due to primary headache disorders or postdural puncture headaches, life-threatening complications can occur. Both postpartum pre-eclampsia can occur as well as hypercoagulable and vascular disorders including stroke, venous sinus thrombosis (VST), and reversible cerebral vasoconstrictive syndrome. With the increasing use of epidurals for intrapartum analgesia, rare, dangerous complications can present in a similar fashion. The authors present a persistent postpartum headache secondary to bilateral subdural hematomas (SDH) from epidural induced intracranial hypotension.

Precision glass molding of diffractive optical elements with high surface quality.

Diffractive optical surfaces have attractive properties for use in optical systems, like reducing weight and correcting for chromatic aberrations, but fabrication of high-quality glass diffractive optics is challenging, preventing it from being widely adopted in commercial applications. In this Letter, we report on a fabrication method to address molding challenges for high-surface-quality diffractive glass optics at molding temperatures up to 550°C, including selection of mold material, mold fabrication, precision glass molding, durability, and stability of the mold. To enable optimal mold machining and easy mold release, nickel phosphorous (NiP) is chosen as the plating material for its cutting performance and anti-adhesion properties, and copper-nickel C71500 (CuNi) is selected as the mold substrate because its coefficient of thermal expansion (CTE) is close to NiP. By the proposed method, diffractive glass optics with 2 nm Sa surface roughness is demonstrated.

Pediatric Cirrhotic Variceal Bleed Precipitating Diabetic Ketoacidosis.

Cirrhosis and its associated complications such, as variceal bleeding, are rare in children, carrying significant morbidity and mortality. Leading causes of cirrhosis in the pediatric population include infection, neoplasm, and metabolic and genetic disorders, which is in contrast to the adult population. Acute gastrointestinal bleeding, as seen with variceal bleeding, has been previously associated with diabetic ketoacidosis through a multifactorial relationship. The case was complicated by hypovolemic shock whose resuscitation and subsequent transfusion was associated with cardiac overload. We highlight the need for balanced, judicious resuscitation in these individuals as well as the need for heightened awareness of coexisting pathologies such as diabetic ketoacidosis.