Mitotically inactivated embryonic stem cells can be used as an in vivo feeder layer to nurse damaged myocardium after acute myocardial infarction: a preclinical study.

RATIONALE: Various types of viable stem cells have been reported to result in modest improvement in cardiac function after acute myocardial infarction. The mechanisms for improvement from different stem cell populations remain unknown. OBJECTIVE: To determine whether irradiated (nonviable) embryonic stem cells (iESCs) improve postischemic cardiac function without adverse consequences. METHODS AND RESULTS: After coronary artery ligation-induced cardiac infarction, either conditioned media or male murine or male human iESCs were injected into the penumbra of ischemic myocardial tissue of female mice or female rhesus macaque monkeys, respectively. Murine and human iESCs, despite irradiation doses that prevented proliferation and induced cell death, significantly improved cardiac function and decreased infarct size compared with untreated or media-treated controls. Fluorescent in situ hybridization of the Y chromosome revealed disappearance of iESCs within the myocardium, whereas 5-bromo-2'-deoxyuridine assays revealed de novo in vivo cardiomyocyte DNA synthesis. Microarray gene expression profiling demonstrated an early increase in metabolism, DNA proliferation, and chromatin remodeling pathways, and a decrease in fibrosis and inflammatory gene expression compared with media-treated controls. CONCLUSIONS: As a result of irradiation before injection, ex vivo and in vivo iESC existence is transient, yet iESCs provide a significant improvement in cardiac function after acute myocardial infarction. The mechanism(s) of action of iESCs seems to be related to cell-cell exchange, paracrine factors, and a scaffolding effect between iESCs and neighboring host cardiomyocytes.

Optimal Image Gain Intensity of Point-of-care Ultrasound when Screening for Ocular Abnormalities in the Emergency Department.

INTRODUCTION: Point-of-care ultrasound (POCUS) plays a pivotal role in evaluating ocular complaints in the emergency department (ED). The rapid and non-invasive nature of ocular POCUS makes it a safe and informative imaging modality. Previous studies have investigated using ocular POCUS to diagnose posterior vitreous detachment (PVD), vitreous hemorrhage (VH), and retinal detachment (RD); however, there are few studies that assess image optimization techniques and how they impact the overall accuracy of ocular POCUS. METHODS: We performed a retrospective review of ED patients who received ocular POCUS examinations and ophthalmology consultations as part of their evaluation for eye complaints at our urban, Level I trauma center ED from November 2017-January 2021. Of 706 exams, 383 qualified for the study. In this study we primarily investigated how stratified gain levels impact the accuracy of ocular POCUS for detection of any posterior chamber pathology and, secondarily, whether stratified gain levels impact the accuracy of detecting RD, VH, and PVD specifically. RESULTS: The images were found to have an overall sensitivity of 81% (76-86%), specificity of 82% (76-88%), positive predictive value (PPV) of 86% (81-91%), and negative predictive value (NPV) of 77% (70-83%). Images acquired with a gain of (25, 50] had a sensitivity of 71% (61-80%), specificity of 95% (85-99%), PPV of 96% (88-99%), and NPV of 68% (56-78%). Images acquired with a gain of (50, 75] had a sensitivity of 85% (73-93%), specificity of 85% (72-93%), PPV of 86% (75-94%), and NPV of 83% (70-92%). Images acquired with a high gain (75, 100] had a sensitivity of 91% (82-97%), specificity of 67% (53-79%), PPV of 78% (68-86%), and NPV of 86% (72-95%). CONCLUSION: In the ED setting, high (75, 100] gain on ocular POCUS scanning has a higher degree of sensitivity for detecting any posterior chamber abnormality, as compared to low (25, 50] gain levels. Thus, incorporating the use of high gain for ocular POCUS exams produces a more effective tool for ocular pathologies in acute care settings and may be particularly valuable in resource-limited settings.

Procedural simulation: medical student preference and value of three task trainers for ultrasound guided regional anesthesia.

BACKGROUND: Ultrasound guided regional anesthesia is widely taught using task trainer models. Commercially available models are often used; however, they can be cost prohibitive. Therefore, alternative "homemade" models with similar fidelity are often used. We hypothesize that professional task trainers will be preferred over homemade models. The purpose of this study is to determine realism, durability and cleanliness of three different task trainers for ultrasound guided nerve blocks. METHODS: This was a prospective observational study using a convenience sample of medical student participants in an ultrasound guided nerve block training session on January 24th, 2015. Participants were asked to perform simulated nerve blocks on three different task trainers including, 1 commercial and 2 homemade. A questionnaire was then given to all participants to rate their experiences both with and without the knowledge on the cost of the simulator device. RESULTS: Data was collected from 25 participants. The Blue Phantom model was found to have the highest fidelity. Initially, 10 (40%) of the participants preferred the Blue Phantom model, while 10 (40%) preferred the homemade gelatin model and 5 (20%) preferred the homemade tofu model. After cost awareness, the majority, 18 (72%) preferred the gelatin model. CONCLUSION: The Blue Phantom model was thought to have the highest fidelity, but after cost consideration the homemade gelatin model was preferred.

Feasibility study of first-year medical students identifying cardiac anatomy using ultrasound in rural Panama.

BACKGROUND: There are over 15 million children who have cardiac anomalies around the world, resulting in a significant morbidity and mortality. Early recognition and treatment can improve the outcomes and lengthen life-expectancy of these patients. The NIH and WHO have promoted guidelines for screening for congenital cardiac anomalies using ultrasound in rural environments. METHODS: Our study took place in Bocas Del Toro, Panama where a mobile clinic was established for community healthcare screening and ultrasonographic evaluation by medical student volunteers and volunteer clinical faculty. This was a non-blinded, investigational study utilizing a convenience sample of pediatric patients presenting for voluntary evaluation. Seven first-year medical students were recruited for the study. These students underwent a training program for advanced cardiac ultrasound instruction, termed "Pediatric Echocardiography Cardiac Screening (PECS)". RESULTS: Ten patients were enrolled in the study. Nine patients had adequate images as defined by the PECS criteria and were all classified as normal cardiac pathology by the medical students, resulting in a sensitivity and specificity of 100%. A single patient was identified by medical students as having a pathologic pulmonic stenosis. This was confirmed as correct by a blinded ultrasonographer. CONCLUSIONS: In this pilot study, the first-year medical students were able to correctly identify pediatric cardiac anatomy and pathology in rural Panama after undergoing a 12-hour ultrasound PECS training session. We believe that with this knowledge, minimally trained practitioners can be used to screen for cardiac anomalies in rural Panama using ultrasound.

Procedural simulation: medical student preference and value of three task trainers for ultrasound guided regional anesthesia / 世界急诊医学杂志（英文）

@#BACKGROUND: Ultrasound guided regional anesthesia is widely taught using task trainer models. Commercially available models are often used; however, they can be cost prohibitive. Therefore, alternative "homemade" models with similar fidelity are often used. We hypothesize that professional task trainers will be preferred over homemade models. The purpose of this study is to determine realism, durability and cleanliness of three different task trainers for ultrasound guided nerve blocks. METHODS: This was a prospective observational study using a convenience sample of medical student participants in an ultrasound guided nerve block training session on January 24th, 2015. Participants were asked to perform simulated nerve blocks on three different task trainers including, 1 commercial and 2 homemade. A questionnaire was then given to all participants to rate their experiences both with and without the knowledge on the cost of the simulator device. RESULTS: Data was collected from 25 participants. The Blue Phantom model was found to have the highest fidelity. Initially, 10 (40%) of the participants preferred the Blue Phantom model, while 10 (40%) preferred the homemade gelatin model and 5 (20%) preferred the homemade tofu model. After cost awareness, the majority, 18 (72%) preferred the gelatin model. CONCLUSION: The Blue Phantom model was thought to have the highest fidelity, but after cost consideration the homemade gelatin model was preferred.

Feasibility study of first-year medical students identifying cardiac anatomy using ultrasound in rural Panama / 世界急诊医学杂志（英文）

BACKGROUND: There are over 15 million children who have cardiac anomalies around the world, resulting in a significant morbidity and mortality. Early recognition and treatment can improve the outcomes and lengthen life-expectancy of these patients. The NIH and WHO have promoted guidelines for screening for congenital cardiac anomalies using ultrasound in rural environments. METHODS: Our study took place in Bocas Del Toro, Panama where a mobile clinic was established for community healthcare screening and ultrasonographic evaluation by medical student volunteers and volunteer clinical faculty. This was a non-blinded, investigational study utilizing a convenience sample of pediatric patients presenting for voluntary evaluation. Seven first-year medical students were recruited for the study. These students underwent a training program for advanced cardiac ultrasound instruction, termed "Pediatric Echocardiography Cardiac Screening (PECS)". RESULTS: Ten patients were enrolled in the study. Nine patients had adequate images as defined by the PECS criteria and were all classified as normal cardiac pathology by the medical students, resulting in a sensitivity and specificity of 100％. A single patient was identified by medical students as having a pathologic pulmonic stenosis. This was confirmed as correct by a blinded ultrasonographer. CONCLUSIONS: In this pilot study, the first-year medical students were able to correctly identify pediatric cardiac anatomy and pathology in rural Panama after undergoing a 12-hour ultrasound PECS training session. We believe that with this knowledge, minimally trained practitioners can be used to screen for cardiac anomalies in rural Panama using ultrasound.