The Atoh7 remote enhancer provides transcriptional robustness during retinal ganglion cell development.

The retinal ganglion cell (RGC) competence factor ATOH7 is dynamically expressed during retinal histogenesis. ATOH7 transcription is controlled by a promoter-adjacent primary enhancer and a remote shadow enhancer (SE). Deletion of the ATOH7 human SE causes nonsyndromic congenital retinal nonattachment (NCRNA) disease, characterized by optic nerve aplasia and total blindness. We used genome editing to model NCRNA in mice. Deletion of the murine SE reduces Atoh7 messenger RNA (mRNA) fivefold but does not recapitulate optic nerve loss; however, SEdel/knockout (KO) trans heterozygotes have thin optic nerves. By analyzing Atoh7 mRNA and protein levels, RGC development and survival, and chromatin landscape effects, we show that the SE ensures robust Atoh7 transcriptional output. Combining SE deletion and KO and wild-type alleles in a genotypic series, we determined the amount of Atoh7 needed to produce a normal complement of adult RGCs, and the secondary consequences of graded reductions in Atoh7 dosage. Together, these data reveal the workings of an evolutionary fail-safe, a duplicate enhancer mechanism that is hard-wired in the machinery of vertebrate retinal ganglion cell genesis.

Suprathreshold contrast response in normal and anomalous trichromats.

Maximum likelihood difference scaling was used to measure suprathreshold contrast response difference scales for low-frequency Gabor patterns, modulated along luminance and L-M color directions in normal, protanomalous, and deuteranomalous observers. Based on a signal-detection model, perceptual scale values, parameterized as $ d^\prime $d', were estimated by maximum likelihood. The difference scales were well fit by a Michaelis-Menten model, permitting estimates of response and contrast gain parameters for each subject. Anomalous observers showed no significant differences in response or contrast gain from normal observers for luminance contrast. For chromatic modulation, however, anomalous observers displayed higher contrast and lower response gain compared to normal observers. These effects cannot be explained by simple pigment shift models, and they support a compensation mechanism to optimize the mapping of the input contrast range to the neural response range. A linear relation between response and contrast gain suggests a neural trade-off between them.

Design and Pilot Study of a High-Fidelity Medical Simulation of a Hospital-Wide Cybersecurity Attack.

Background: Cybersecurity incidents affecting hospitals have grown in prevalence and consequence over the last two decades, increasing the importance of cybersecurity preparedness and response training to minimize clinical disruptions. This work describes the development, execution, and post-exercise assessment of a novel simulation scenario consisting of four interlocking intensive care unit (ICU) patient scenarios. This simulation was designed to demonstrate the management of acute pathologies without access to conventional treatment methods during a cybersecurity incident in order to raise clinician awareness of the increasing incidence and patient safety implications of such events. Methods: The simulation was developed by a multidisciplinary team of physicians, simulation experts, and medical education experts at UCSD School of Medicine. The simulation involves the treatment of four patients, respectively experiencing postoperative hemorrhage, end stage renal disease, diabetic ketoacidosis, and hypoxic respiratory failure, all without access to networked medical resources. The simulation was first executed as part of the proceedings of CyberMed Summit, a healthcare cybersecurity conference in La Jolla, California, on November 19th, 2022. Following the simulation, a debrief session was held with the learner in front of conference attendees, with additional questioning and discussion prompted by attendee input. Results: Though limited to a single subject by the pilot-study nature of this research, the physician learner successfully identified the acute etiologies and managed the patients' acute decompensations while lacking access to the hospital's electronic medical records (EMRs), laboratory results, imaging, and communication systems. Review of footage of the event and post-experience interviews yielded numerous insights on the specific physician-focused challenges and possible solutions to a hospital-infrastructure-crippling cyber attack. Conclusion: Healthcare cybersecurity incidents are known to result in significant disruption of clinical activities and can be viewed through a patient-safety oriented perspective. Simulation training may be a particularly effective method for raising clinician awareness of and preparedness for these events, though further research is required.

Building Affordable, Durable, Medium-fidelity Ballistic Gel Phantoms for Ultrasound-guided Nerve Block Training.

Ultrasound phantoms - alternatives to live human tissue - give learners the opportunity to practice ultrasound-guided regional anesthesia without introducing undue risk to patients. Gelatin-based phantoms provide educators with durable and reusable task trainers; however, commercially available gel-based phantoms are expensive. Here, we investigate the production of durable, low-cost, ballistic gel-based ultrasound phantoms for median, femoral, suprainguinal fascia iliaca plane, and serratus anterior plane nerve blocks, as well as a methodology for producing a phantom for any ultrasound-guided nerve block procedure. Computer-aided design (CAD) software was utilized to design four phantoms replicating the anatomy of median, femoral, suprainguinal fascia iliaca plane, and serratus anterior plane nerve blocks, including relevant landmarks and tissue planes. Plastic models of the desired tissue planes were 3D printed and used to create silicone molds. Ballistic gel was melted and mixed with flour and dye to create a liquid, echogenic ballistic gel, which was poured into the silicone molds. Vessels were simulated by creating negative space in the ballistic gel using metal rods. Nerves were simulated using yarn submerged in ultrasound gel. Simulated bones were designed using CAD and 3D printed. Ballistic gel is a versatile, durable medium that can be used to simulate a variety of tissues and can be melted and molded into any shape. Under ultrasound, these phantoms provide realistic tissue planes that represent the borders between different layers of skin, muscle, and fascia. The echogenicity of the muscle tissue layers, nerves, vessels, and bones is realistic, and bones have significant posterior shadowing as would be observed in a human subject. These phantoms cost $200 each for the first phantom and $60 for each subsequent phantom. These phantoms require some technical skill to design, but they can be built for just 4% of the cost of their commercial counterparts.

Effectiveness of rescue Me CPR! smartphone app providing real-time guidance to untrained bystanders performing CPR.

Background: Out-of-hospital cardiac arrest (OHCA) is a persistent global health challenge, owing, in part, to low rates of population CPR training. Smartphone applications have the potential to widely disseminate CPR basic training to a populace, but other studies have found multiple limitations in previously developed CPR guidance applications (CPR-GA). This study aims to use medical simulation to assess the relative CPR performance of novices using the 'Rescue Me CPR!' (RMC) app, a custom CPR-GA designed by this research team, to novices using 'PG-CPR!' (PGC), the most downloaded CPR-GA available in the USA, and to CPR certified medical personnel. Methods: In a prospective randomized experimental trial of 60 individuals, subjects were either given the RMC app, the PGC app, or had active CPR certification. They were presented a cardio-pulmonary arrest scenario and were observed while performing CPR on a high-fidelity manikin. Data was collected through four cycles of CPR, during which time 24 pertinent performance metrics and CPR steps were timed and recorded. These metrics were assessed on their own and used to calculate average time to compressions, average chest compression fraction, and rate of high-quality CPR for each study group. Results: CPR certified subjects called 911 in 100 % of simulation cases, started compressions 34 ± 10 s after first seeing the simulated patient, had an average chest compression fraction of 0.52, and performed high-quality CPR in 25 % of aggregate compression cycles. PGC app users called 911 in 70 % of simulation cases, started compressions 86 ± 17 s after first seeing the simulated patient, had an average chest compression fraction that could not be assessed due to inconsistent pauses during CPR, and performed high-quality CPR in 2.5 % of aggregate compression cycles. RMC app users called 911 in 100 % of simulation cases, started compressions 55 ± 6 s after first seeing the simulated patient, had an average chest compression fraction of 0.48, and performed high-quality CPR in 50 % of aggregate compression cycles. Conclusion: The results of this study demonstrate that in all studied metrics, except time-to-first-compression, CPR provided by individuals using the RMC app is statistically equivalent or superior to CPR performed by a CPR certified individual and, in almost every metric, superior to CPR performed by users of the most downloaded android CPR guidance application, PG-CPR.

Endotracheal tube forces exerted on the larynx and a novel support device to reduce it.

Objective: Endotracheal tubes (ETTs) are commonly associated with laryngeal injury that may be short lasting and temporary or more severe and life altering. Injury is believed to result from forces that these ETTs exert on the larynx. Here we quantify the forces of ETTs of various sizes on the laryngotracheal complex to gain a more quantitative understanding of these potential damaging forces. Here we also perform preclinical testing of a novel support device to offload these forces. Methods: Endotracheal intubation was performed on a fresh human cadaver using various ETT sizes. A strain-sensitive graphene nanosheet sensor and a commercially available force sensing resistor were secured behind the larynx, anterior to the prevertebral fascia. The forces exerted on the larynx were measured for each of the commonly used ETTs. A novel support device, ETT clip (Endo Clip), was attached to the ETTs and changes in these forces were observed. Results: Forces exerted on the laryngotracheal complex by various ETTs were observed to increase with increasing tube size. This pressure can be significantly reduced with a novel ETT clip. Conclusion: Here we demonstrate the first quantitative measurement of forces that ETTs exert on the larynx. We demonstrate a novel device that can easily clip onto an ETT reducing pressure on the laryngotracheal complex. This preclinical test paves the way for a human clinical trial. Level of evidence: 5.

Relative Effects of Various Factors on Ice Ball Formation and Ablation Zone Size During Ultrasound-Guided Percutaneous Cryoneurolysis: A Laboratory Investigation to Inform Clinical Practice and Future Research.

INTRODUCTION: Ultrasound-guided percutaneous cryoneurolysis provides analgesia using cold temperatures to reversibly ablate peripheral nerves. Cryoneurolysis probes pass a gas through a small internal annulus, rapidly lowering the pressure and temperature, forming an ice ball to envelope the target nerve. Analgesia is compromised if a nerve is inadequately frozen, and laboratory studies suggest that pain may be paradoxically induced with a magnitude and duration in proportion with the incomplete ablation. We therefore investigated the relative effects of various factors that may contribute to the size of the ice ball and the effective cryoneurolysis zone. METHODS: A cryoprobe was inserted into a piece of meat, a gas was passed through for 2 min, and the resulting ice ball width (cross-section) and length (axis parallel to the probe) were measured using ultrasound, with the temperature evaluated in nine concentric locations concurrently. RESULTS: The factor with the greatest influence on ice ball size was probe gauge: in all probe types, a change from 18 to 14 increased ice ball width, length, and volume by up to 70%, 113%, and 512% respectively, with minimum internal temperature decreasing as much as from -5 to -32 °C. In contrast, alternating the type of meat (chicken, beef, pork) and the shape of the probe tip (straight, coudé) affected ice ball dimensions to a negligible degree. The ice ball dimensions and the zone of adequate temperature drop were not always correlated, and, even within a visualized ice ball, the temperature was often inadequate to induce Wallerian degeneration. CONCLUSIONS: Percutaneous probe design can significantly influence the effective cryoneurolysis zone; visualizing a nerve fully encompassed in an ice ball does not guarantee adequate treatment to induce the desired Wallerian degeneration because ice forms at temperatures between 0 and -20 °C, whereas only temperatures below -20 °C induce Wallerian degeneration. The correlation between temperatures in isolated pieces of meat and perfused human tissue remains unknown, and further research to evaluate these findings in situ appears highly warranted.

Using directional OCT to analyze photoreceptor visibility over AMD-related drusen.

Investigators have reported reduced visibility of the cone photoreceptors overlying drusen using adaptive optics (AO) imaging techniques. Two hypotheses have been proposed to explain this phenomenon. First, the disease-related deformation of the photoreceptor outer segment (OS) may reduce its ability to act as a wave guide, thus decreasing the cell's familiar reflectance pattern. Second, drusen could disorient the photoreceptors away from the eye's pupil, reducing the amount of light reflected back out the pupil. In this work, we use directional OCT (dOCT) images of drusen in AMD patients to measure the respective contributions of these deforming and disorienting factors.

Pregnancy-associated large pelvic desmoid tumor: A case report of fetal-protective strategies and fertility preservation.

•Desmoid fibromatoses grow rapidly during the high estrogen-state of pregnancy.•Mass effect on the bladder is a complication of abdominal desmoid fibromatoses.•Cryoablation, doxorubicin, and post-partum prolactin are fetal-protective treatments.•Desmoid tumors can be effectively treated with fetal-protective strategies.

Adaptive Changes in Color Vision from Long-Term Filter Usage in Anomalous but Not Normal Trichromacy.

For over 150 years, spectrally selective filters have been proposed to improve the vision of observers with color vision deficiencies [1]. About 6% of males and <1% of females have anomalies in their gene arrays coded on the X chromosome that result in significantly decreased spectral separation between their middle- (M-) and long- (L-) wave sensitive cone photoreceptors [2]. These shifts alter individuals' color-matching and chromatic discrimination such that they are classified as anomalous trichromats [3, 4]. Broad-band spectrally selective filters proposed to improve the vision of color-deficient observers principally modify the illuminant and are largely ineffective in enhancing discrimination or perception because they do not sufficiently change the relative activity of M- and L-photoreceptors [5, 6]. Properly tailored notch filters, by contrast, might increase the difference of anomalous M- and L-cone signals. Here, we evaluated the effects of long-term usage of a commercial filter designed for this purpose on luminance and chromatic contrast response, estimated with a signal detection-based scaling method. We found that sustained use over two weeks was accompanied by increased chromatic contrast response in anomalous trichromats. Importantly, these improvements were observed when tested without the filters, thereby demonstrating an adaptive visual response. Normal observers and a placebo control showed no such changes in contrast response. These findings demonstrate a boosted chromatic response from exposure to enhanced chromatic contrasts in observers with reduced spectral discrimination. They invite the suggestion that modifications of photoreceptor signals activate a plastic post-receptoral substrate that could potentially be exploited for visual rehabilitation.

Automated quantification of choriocapillaris anatomical features in ultrahigh-speed optical coherence tomography angiograms.

In vivo visualization and quantification of choriocapillaris vascular anatomy is a fundamental step in understanding the relation between choriocapillaris degradation and atrophic retinopathies, including geographic atrophy. We describe a process utilizing ultrahigh-speed swept-source optical coherence tomography and a custom-designed "local min-max normalized masking" algorithm to extract in vivo anatomical metrics of the choriocapillaris. We used a swept-source optical coherence tomography system with a 1.6 MHz A-scan rate to image healthy retinas. With the postprocessing algorithm, we reduced noise, optimized visibility of vasculature, and skeletonized the vasculature within the images. These skeletonizations were in 89 % agreement with those made by skilled technicians and were, on average, completed in 18.6 s as compared to the 5.6 h technicians required. Anatomy within the processed images and skeletonizations was analyzed to identify average values ( mean ± SD ) of flow void radius ( 9.8 ± 0.7 µm ), flow void area ( 749 ± 110 µm 2 ), vessel radius ( 5.0 ± 0.3 µm ), branch-point to branch-point vessel length ( 26.8 ± 1.1 µm ), and branches per branch-point ( 3.1 ± 0.1 ) . To exemplify the uses of this tool a retina with geographic atrophy was imaged and processed to reveal statistically significant ( p < 0.05 ) increases in flow void radii and decreases in vessel radii under atrophic lesions as compared to atrophy-free regions on the same retina. Our results demonstrate a new avenue for quantifying choriocapillaris anatomy and studying vasculature changes in atrophic retinopathies.

The Allosteric Site on SHP2's Protein Tyrosine Phosphatase Domain is Targetable with Druglike Small Molecules.

Difficulties in developing active-site-directed protein tyrosine phosphatase (PTP) inhibitors have led to the perception that PTPs are "undruggable", highlighting the need for new means to target pharmaceutically important PTPs allosterically. Recently, we characterized an allosteric-inhibition site on the PTP domain of Src-homology-2-domain-containing PTP 2 (SHP2), a key anticancer drug target. The central feature of SHP2's allosteric site is a nonconserved cysteine residue (C333) that can potentially be labeled with electrophilic compounds for selective SHP2 inhibition. Here, we describe the first directed discovery effort for C333-targeted allosteric SHP2 inhibitors. By screening a previously reported library of reversible, covalent inhibitors, we identified a lead compound, which was modified to yield an irreversible inhibitor (12), that inhibits SHP2 allosterically and selectively through interaction with C333. These findings provide a novel paradigm for allosteric-inhibitor discovery on SHP2, one that may help to circumvent the challenges inherent in targeting SHP2's active site.