Labile assembly of a tardigrade protein induces biostasis

Tardigrades are microscopic animals that survive desiccation by inducing biostasis. To survive drying tardigrades rely on intrinsically disordered CAHS proteins, which also function to prevent perturbations induced by drying in vitro and in heterologous systems. CAHS proteins have been shown to form gels both in vitro and in vivo, which has been speculated to be linked to their protective capacity. However, the sequence features and mechanisms underlying gel formation and the necessity of gelation for protection have not been demonstrated. Here we report a mechanism of fibrillization and gelation for CAHS D similar to that of intermediate filament assembly. We show that in vitro, gelation restricts molecular motion, immobilizing and protecting labile material from the harmful effects of drying. In vivo, we observe that CAHS D forms fibrillar networks during osmotic stress. Fibrillar networking of CAHS D improves survival of osmotically shocked cells. We observe two emergent properties associated with fibrillization; (i) prevention of cell volume change and (ii) reduction of metabolic activity during osmotic shock. We find that there is no significant correlation between maintenance of cell volume and survival, while there is a significant correlation between reduced metabolism and survival. Importantly, CAHS D's fibrillar network formation is reversible and metabolic rates return to control levels after CAHS fibers are resolved. This work provides insights into how tardigrades induce reversible biostasis through the self-assembly of labile CAHS gels.

Early intervention and disease modification in atopic dermatitis-the current state of the field and barriers to progress

Atopic dermatitis (AD) is a highly prevalent chronic inflammatory skin disease representing a major source of global disability burden. Disease-modifying therapies are showing promise in chronic inflammatory disorders such as rheumatoid arthritis and Crohn's disease with method and timing of initial treatment impacting long-term disease outcomes. Whether disease-modifying therapies, specifically those used as an early interventional approach, impacts disease course and comorbidity development in AD is not well-understood. We reviewed the progress in disease modification strategies, emphasizing early intervention approaches in common (or proto-typical) inflammatory diseases. Although more common in other fields, disease modification approaches are becoming increasingly investigated in dermatology, though studies in AD are lacking. Despite significant limitations in ongoing and completed studies, early data are promising and suggest that both the choice and timing of early intervention approach can affect long-term disease course and comorbidity development. To best improve AD patient outcomes, more research is needed to further explore the impact of early disease-modifying therapies. Future studies should focus on identifying the most effective approaches and extend the early results to a more inclusive set of comorbidities and longer-term outcomes.

Asian Cohort for Alzheimer's Disease (ACAD) pilot study on genetic and non-genetic risk factors for Alzheimer's disease among Asian Americans and Canadians

INTRODUCTION

Clinical research in Alzheimer's disease (AD) lacks cohort diversity despite being a global health crisis. The Asian Cohort for Alzheimer's Disease (ACAD) was formed to address underrepresentation of Asians in research, and limited understanding of how genetics and non-genetic/lifestyle factors impact this multi-ethnic population.

METHODS

The ACAD started fully recruiting in October 2021 with one central coordination site, eight recruitment sites, and two analysis sites. We developed a comprehensive study protocol for outreach and recruitment, an extensive data collection packet, and a centralized data management system, in English, Chinese, Korean, and Vietnamese.

RESULTS

ACAD has recruited 606 participants with an additional 900 expressing interest in enrollment since program inception.

DISCUSSION

ACAD's traction indicates the feasibility of recruiting Asians for clinical research to enhance understanding of AD risk factors. ACAD will recruit > 5000 participants to identify genetic and non-genetic/lifestyle AD risk factors, establish blood biomarker levels for AD diagnosis, and facilitate clinical trial readiness.

HIGHLIGHTS

The Asian Cohort for Alzheimer's Disease (ACAD) promotes awareness of under-investment in clinical research for Asians. We are recruiting Asian Americans and Canadians for novel insights into Alzheimer's disease. We describe culturally appropriate recruitment strategies and data collection protocol. ACAD addresses challenges of recruitment from heterogeneous Asian subcommunities. We aim to implement a successful recruitment program that enrolls across three Asian subcommunities.

Demonstrating Agreement between Radio and Fluorescence Measurements of the Depth of Maximum of Extensive Air Showers at the Pierre Auger Observatory

We show, for the first time, radio measurements of the depth of shower maximum (X_{max}) of air showers induced by cosmic rays that are compared to measurements of the established fluorescence method at the same location. Using measurements at the Pierre Auger Observatory we show full compatibility between our radio and the previously published fluorescence dataset, and between a subset of air showers observed simultaneously with both radio and fluorescence techniques, a measurement setup unique to the Pierre Auger Observatory. Furthermore, we show radio X_{max} resolution as a function of energy and demonstrate the ability to make competitive high-resolution X_{max} measurements with even a sparse radio array. With this, we show that the radio technique is capable of cosmic-ray mass composition studies, both at Auger and at other experiments.

Natural history of occult hernias in adults at a safety-net hospital

PURPOSE

Occult hernias, hernias seen on radiologic imaging but not felt on physical exam, are common. Despite their high prevalence, little is known about the natural history of this finding. Our aim was to determine and report on the natural history of patients with occult hernias including the impact on abdominal wall quality of life (AW-QOL), need for surgery, and risk of acute incarceration/strangulation.

METHODS

This was a prospective cohort study of patients who underwent a computed tomography (CT) abdomen/pelvis scan from 2016 to 2018. Primary outcome was change in AW-QOL using the modified Activities Assessment Scale (mAAS), a hernia-specific, validated survey (1 = poor, 100 = perfect). Secondary outcomes included elective and emergent hernia repairs.

RESULTS

A total of 131 (65.8%) patients with occult hernias completed follow-up with a median (IQR) of 15.4 (22.5) months. Nearly half of these patients (42.8%) experienced a decrease in their AW-QOL, 26.0% were unchanged, and 31.3% reported improvement. One-fourth of patients (27.5%) underwent abdominal surgery during the study period: 9.9% were abdominal procedures without hernia repair, 16.0% involved elective hernia repairs, and 1.5% were emergent hernia repairs. AW-QOL improved for patients who underwent hernia repair (+ 11.2 ± 39.7, p = 0.043) while those who did not undergo hernia repair experienced no change in AW-QOL (- 3.0 ± 35.1).

CONCLUSION

When untreated, patients with occult hernias on average experience no change in their AW-QOL. However, many patients experience improvement in AW-QOL after hernia repair. Additionally, occult hernias have a small but real risk of incarceration requiring emergent repair. Further research is needed to develop tailored treatment strategies.

Energetic Electron Precipitation Driven by Electromagnetic Ion Cyclotron Waves from ELFIN's Low Altitude Perspective

We review comprehensive observations of electromagnetic ion cyclotron (EMIC) wave-driven energetic electron precipitation using data collected by the energetic electron detector on the Electron Losses and Fields InvestigatioN (ELFIN) mission, two polar-orbiting low-altitude spinning CubeSats, measuring 50-5000 keV electrons with good pitch-angle and energy resolution. EMIC wave-driven precipitation exhibits a distinct signature in energy-spectrograms of the precipitating-to-trapped flux ratio: peaks at >0.5 MeV which are abrupt (bursty) (lasting ∼17 s, or Δ L ∼ 0.56 ) with significant substructure (occasionally down to sub-second timescale). We attribute the bursty nature of the precipitation to the spatial extent and structuredness of the wave field at the equator. Multiple ELFIN passes over the same MLT sector allow us to study the spatial and temporal evolution of the EMIC wave - electron interaction region. Case studies employing conjugate ground-based or equatorial observations of the EMIC waves reveal that the energy of moderate and strong precipitation at ELFIN approximately agrees with theoretical expectations for cyclotron resonant interactions in a cold plasma. Using multiple years of ELFIN data uniformly distributed in local time, we assemble a statistical database of ∼50 events of strong EMIC wave-driven precipitation. Most reside at L ∼ 5 - 7 at dusk, while a smaller subset exists at L ∼ 8 - 12 at post-midnight. The energies of the peak-precipitation ratio and of the half-peak precipitation ratio (our proxy for the minimum resonance energy) exhibit an L -shell dependence in good agreement with theoretical estimates based on prior statistical observations of EMIC wave power spectra. The precipitation ratio's spectral shape for the most intense events has an exponential falloff away from the peak (i.e., on either side of ∼ 1.45 MeV). It too agrees well with quasi-linear diffusion theory based on prior statistics of wave spectra. It should be noted though that this diffusive treatment likely includes effects from nonlinear resonant interactions (especially at high energies) and nonresonant effects from sharp wave packet edges (at low energies). Sub-MeV electron precipitation observed concurrently with strong EMIC wave-driven >1 MeV precipitation has a spectral shape that is consistent with efficient pitch-angle scattering down to ∼ 200-300 keV by much less intense higher frequency EMIC waves at dusk (where such waves are most frequent). At ∼100 keV, whistler-mode chorus may be implicated in concurrent precipitation. These results confirm the critical role of EMIC waves in driving relativistic electron losses. Nonlinear effects may abound and require further investigation.

Cannabis use for Sleep Disturbance Among Older Patients in a Geriatrics Clinic

Cannabis use is growing among older adults to manage medical concerns including poor sleep. In this study, we characterized how patients seen at a geriatrics clinic use cannabis to address sleep disturbance. Specifically, we conducted an anonymous survey of 568 adults, including 83 who reported cannabis use within the past 3 years, to inquire about such use. We compared cannabis use characteristics between those using it for sleep disturbance versus all other conditions. We considered a p-value <.10 to be statistically significant. Among the cannabis users in our sample, 29% reported using cannabis for sleep disturbance (N = 24). They were more likely than other users to be female (p = .07), consume cannabis more frequently (p = .01), use products containing tetrahydrocannabinol (THC) (vs. cannabidiol [CBD]-only; p < .01), and use cannabis to target more symptoms (p < .01). As cannabis use continues to grow in older populations, it is essential to delineate better how cannabis may be used safely and effectively to improve older adults' sleep health.

A short, animated storytelling video about sodium intake as a major cardiovascular risk factor and recommendations for a healthy diet: an online, randomized, controlled trial

BACKGROUND

Increased uptake of sodium is a major cause for cardiovascular disease and mortality. Reduction of daily salt intake below a reference level of 2 g per day (the equivalent to 5 g salt/day) is known to effectively reduce cardiovascular mortality. The widespread use of social media, with a constant increase in video consumption, is opening new avenues for the dissemination of innovative and scalable approaches to health-related information and recommendations for a healthy diet, such as via video interventions with short animated stories (SAS).

OBJECTIVE

This study will evaluate the effect of a sodium intake-SAS video intervention on immediate and medium-term knowledge about dietary sodium. Beyond that, immediate and medium-term effects on behavioral expectation to reduce sodium intake as well as voluntary post-trial engagement with the video content will be examined.

METHODS

In this 4-armed, parallel, randomized controlled trial, 10,000 adult, US participants will be randomly assigned to (1) a short, animated storytelling intervention video on sodium as a cardiovascular disease risk factor followed by surveys assessing the facts on sodium and cardiovascular disease conveyed in the video (2) the surveys only, (3) an attention placebo control video followed by the before mentioned surveys, and (4) an arm that is exposed to neither the video nor the surveys. Two weeks later, participants in all four arms will complete all of the surveys.

RESULTS

Primary outcomes are the immediate and medium-term effects of the short, animated storytelling intervention video on knowledge about dietary sodium. Secondary outcomes are immediate and medium-term effects of the short, animated storytelling intervention on behavioral expectation to reduce sodium intake as well as voluntary post-trial engagement with the video content.

CONCLUSION

This study will extend the knowledge on the effects of short, animated storytelling for the containment of the global cardiovascular disease burden. Knowledge on the groups that may be more likely to voluntarily engage with SAS video content will help to improve targeting of future interventions towards audiences at risk. TRIAL REGISTRATION {2A}: ClinicalTrials.gov NCT05735457. Registered on February 21, 2023.

Machine Learning Classification of Alzheimer's Disease Pathology Reveals Diffuse Amyloid as a Major Predictor of Cognitive Impairment in Human Hippocampal Subregions

Analyzing Alzheimer's disease (AD) pathology within anatomical subregions is a significant challenge, often carried out by pathologists using a standardized, semi-quantitative approach. To augment traditional methods, a high-throughput, high-resolution pipeline was created to classify the distribution of AD pathology within hippocampal subregions. USC ADRC post-mortem tissue sections from 51 patients were stained with 4G8 for amyloid, Gallyas for neurofibrillary tangles (NFTs) and Iba1 for microglia. Machine learning (ML) techniques were utilized to identify and classify amyloid pathology (dense, diffuse and APP (amyloid precursor protein)), NFTs, neuritic plaques and microglia. These classifications were overlaid within manually segmented regions (aligned with the Allen Human Brain Atlas) to create detailed pathology maps. Cases were separated into low, intermediate, or high AD stages. Further data extraction enabled quantification of plaque size and pathology density alongside ApoE genotype, sex, and cognitive status. Our findings revealed that the increase in pathology burden across AD stages was driven mainly by diffuse amyloid. The pre and para-subiculum had the highest levels of diffuse amyloid while NFTs were highest in the A36 region in high AD cases. Moreover, different pathology types had distinct trajectories across disease stages. In a subset of AD cases, microglia were elevated in intermediate and high compared to low AD. Microglia also correlated with amyloid pathology in the Dentate Gyrus. The size of dense plaques, which may represent microglial function, was lower in ApoE4 carriers. In addition, individuals with memory impairment had higher levels of both dense and diffuse amyloid. Taken together, our findings integrating ML classification approaches with anatomical segmentation maps provide new insights on the complexity of disease pathology in AD progression. Specifically, we identified diffuse amyloid pathology as being a major driver of AD in our cohort, regions of interest and microglial responses that might advance AD diagnosis and treatment.

Radiation Therapy Decision Making Process and Operations for COVID-19 Positive Patients

Purpose/Objective(s)

A challenging clinical dilemma during the COVID-19 pandemic is management of cancer patients who test positive for COVID. Given the need to balance the risk of disease progression with the risk of transmission to other patients and staff, radiation therapy for these patients requires careful consideration and modification of standard workflows. It is also critical to develop processes to mitigate radiation treatment interruption, which can affect patient outcomes. The objective of this study was to report the clinical operations and outcomes for COVID positive patients receiving radiation therapy during the pandemic at a tertiary cancer center including 2 network locations.

Materials/Methods

During March 2020 to March 2022, the Radiation Oncology COVID committee (RO COVID) developed an integrated process to triage patients, provide treatment recommendations, and implement infection control procedures to safely deliver radiation therapy to COVID positive patients. Policies were created for each center with multidisciplinary input from infectious disease, radiation oncology, radiation therapy, and nursing. All COVID positive patients were presented to the RO COVID group and evaluated for clinical urgency, benefit with radiation, and life expectancy. If deemed necessary, a limited planned break or hypofractionated regimen was recommended to minimize staff exposure. We conducted a retrospective review of COVID positive patients with different primary malignancies treated through the COVID positive pathway.

Results

A total of 68 COVID positive patients were treated with the COVID positive pathway (HN 15, Breast 9, CNS 8, GU 8, GYN, 7, Thoracic 6, GI 5, HEME 5, PED 3, SARC 2). The median age was 57.1 years (IQR 45.8-63.4) and 47% were female. There were 39 patients (57%) who were asymptomatic and were tested for routine pre-radiation screening or due to concerns of COVID exposure. Twenty-three (34%) patients were treated with palliative intent and 8 (12%) were treated for an emergent indication (i.e., spinal cord compression, bleeding). Thirteen (19%) patients were receiving radiation treatment, had a treatment break (7-21 days), and then resumed their radiation course. All treatments were successfully completed without known nosocomial spread of COVID to staff or other patients. Among this heterogenous group of patients, 58 (85%) were alive with a median follow up of 2 months (IQR 0.5-7.5). COVID infection may have contributed to 3 out of 10 deaths (4% of total cohort). The remaining deaths were due to progression of disease or other non-COVID causes.

Conclusion

In this study, COVID positive patients were safely treated with radiation therapy through a comprehensive decision making and clinical operations pathway taking into account evolving COVID guidelines for three different variant surges. Although limited in follow up, patient outcomes are promising with few COVID-related deaths and low overall mortality rates, even with hypofractionated regimens.

TREM2 drives microglia response to amyloid-β via SYK-dependent and -independent pathways

Genetic studies have highlighted microglia as pivotal in orchestrating Alzheimer's disease (AD). Microglia that adhere to Aβ plaques acquire a transcriptional signature, "disease-associated microglia" (DAM), which largely emanates from the TREM2-DAP12 receptor complex that transmits intracellular signals through the protein tyrosine kinase SYK. The human TREM2R47H variant associated with high AD risk fails to activate microglia via SYK. We found that SYK-deficient microglia cannot encase Aβ plaques, accelerating brain pathology and behavioral deficits. SYK deficiency impaired the PI3K-AKT-GSK-3β-mTOR pathway, incapacitating anabolic support required for attaining the DAM profile. However, SYK-deficient microglia proliferated and advanced to an Apoe-expressing prodromal stage of DAM; this pathway relied on the adapter DAP10, which also binds TREM2. Thus, microglial responses to Aβ involve non-redundant SYK- and DAP10-pathways. Systemic administration of an antibody against CLEC7A, a receptor that directly activates SYK, rescued microglia activation in mice expressing the TREM2R47H allele, unveiling new options for AD immunotherapy.

Secretion and Uptake of Copper via a Small Copper Carrier in Blood Fluid

Studies with Wilson disease model mice that accumulate excessive copper, due to a dysfunctional ATP7B “copper pump” resulting in decreased biliary excretion, showed that the compensatory increase in urinary copper loss was due to a small copper carrier (∼1 kDa) (SCC). We show here that SCC is also present in the blood plasma of normal and Wilson disease model mice and dogs, as determined by ultrafiltration and size exclusion chromatography (SEC). It is secreted by cultured hepatic and enterocytic cells, as determined by pretreatment with ⁶⁷Cu nitrilotriacetate (NTA) or nonradioactive 5–10 μM Cu-NTA, and collecting and examining 3 kDa ultrafiltrates of the conditioned media, where a single major copper peak is detected by SEC. Four different cultured cell types exposed to the radiolabeled SCC all took up the ⁶⁷Cu at various rates. Rates differed somewhat when uptake was from Cu-NTA. Uptake of SCC-⁶⁷Cu was inhibited by excess nonradioactive Cu(I) or Ag(I) ions, suggesting competition for uptake by copper transporter 1 (CTR1). Knockout of CTR1 in fibroblasts reduced uptake rates by 60%, confirming its participation, but also involvement of other transporters. Inhibitors of endocytosis, or an excess of metal ions taken up by divalent metal transporter 1, did not decrease SCC-⁶⁷Cu uptake. The results imply that SCC may play a significant role in copper transport and homeostasis, transferring copper particularly from the liver (but also intestinal cells) to other cells within the mammalian organism, as well as spilling excess into the urine in copper overload—as an alternative means of copper excretion.

Caloric restriction in humans reveals immunometabolic regulators of health span

The extension of life span driven by 40% caloric restriction (CR) in rodents causes trade-offs in growth, reproduction, and immune defense that make it difficult to identify therapeutically relevant CR-mimetic targets. We report that about 14% CR for 2 years in healthy humans improved thymopoiesis and was correlated with mobilization of intrathymic ectopic lipid. CR-induced transcriptional reprogramming in adipose tissue implicated pathways regulating mitochondrial bioenergetics, anti-inflammatory responses, and longevity. Expression of the gene Pla2g7 encoding platelet activating factor acetyl hydrolase (PLA2G7) is inhibited in humans undergoing CR. Deletion of Pla2g7 in mice showed decreased thymic lipoatrophy, protection against age-related inflammation, lowered NLRP3 inflammasome activation, and improved metabolic health. Therefore, the reduction of PLA2G7 may mediate the immunometabolic effects of CR and could potentially be harnessed to lower inflammation and extend the health span.

Machine learning-based approaches for identifying human blood cells harboring CRISPR-mediated fetal chromatin domain ablations

Two common hemoglobinopathies, sickle cell disease (SCD) and β-thalassemia, arise from genetic mutations within the β-globin gene. In this work, we identified a 500-bp motif (Fetal Chromatin Domain, FCD) upstream of human ϒ-globin locus and showed that the removal of this motif using CRISPR technology reactivates the expression of ϒ-globin. Next, we present two different cell morphology-based machine learning approaches that can be used identify human blood cells (KU-812) that harbor CRISPR-mediated FCD genetic modifications. Three candidate models from the first approach, which uses multilayer perceptron algorithm (MLP 20-26, MLP26-18, and MLP 30-26) and flow cytometry-derived cellular data, yielded 0.83 precision, 0.80 recall, 0.82 accuracy, and 0.90 area under the ROC (receiver operating characteristic) curve when predicting the edited cells. In comparison, the candidate model from the second approach, which uses deep learning (T2D5) and DIC microscopy-derived imaging data, performed with less accuracy (0.80) and ROC AUC (0.87). We envision that equivalent machine learning-based models can complement currently available genotyping protocols for specific genetic modifications which result in morphological changes in human cells.

SURPRISINGLY FEW WOMEN WITH SEVERE OSTEOPOROSIS BY BONE DENSITOMETRY UNDERGO WORKUP FOR SECONDARY CAUSES - A RETROSPECTIVE EVALUATION

We describe clinical features of women with extremely low bone density, and investigate secondary causes of osteoporosis. Our hypothesis was that this population would be enriched in identifiable causes of osteoporosis. We performed a retrospective review of medical records of all women seen at our university over 4 years with T-score on bone densitometry at/below -4 at any site. Historical and fracture details were abstracted. We considered a thorough work up to include Vitamin D, PTH, CBC, chemistry panel, cortisol, transglutaminase, myeloma screen, tryptase and 24-hour urine calcium.

RESULTS

137 women were identified with T-score at/below -4. Percent identified as Asian was 26% (higher than local prevalence of 8%). Average BMI was 21.6 kg/m². Clearly identifiable causes of osteoporosis were noted in 57% (inflammatory disorder, glucocorticoid or antacid exposure, prolonged immobilization and alcoholism were most prevalent). Of the remainder, full work up was performed only in 8%. Endocrine consultation and white race predicted thoroughness of secondary work-up.

CONCLUSION

Fragility fractures, leanness and Asian race were common in women with very low T-score. However, few new causes were identified. Underlying etiology was either immediately evident or inadequately studied, especially in minorities.

Abstract 371: A single-center retrospective review assessing the use of tumor mutation burden as a predictor of therapeutic success in patients receiving immunotherapy

Background

Cancer is a genetic disease in which cells may accumulate somatic mutations. The measurement of the frequency these somatic mutations occur is referred to as tumor mutational burden or TMB. A minority of these mutations may give rise to neoantigens that could in turn be recognized and targeted by the immune system. The more somatic mutations a tumor develops, the more likely these neoantigens are to form. Recent studies, namely KEYNOTE-158, found high TMB status to be associated with improved outcomes in patients receiving pembrolizumab monotherapy.

Materials and Methods

This was a single-center retrospective study that analyzed 73 patients who received cancer treatment at Avera Cancer Institute between June 2016 and July 2019. Patients were included/excluded from the final analysis based on having received at least one dose of pembrolizumab, ipilimumab, and/or nivolumab. Information was collected on patient characteristics, treatment, and clinical outcomes. The primary outcomes were complete and partial response rates and were assessed objectively based on a composite of radiographic reports, physician documentation, and treatment course. Secondary outcomes were clinical outcomes in patients with PD-1 and/or PD-L1 expression, clinical outcomes in patients receiving mono-immunotherapy vs combination therapy, and clinical outcomes based on the line of treatment in which immunotherapy was utilized.

Results

A total of 34 patients met the inclusion criteria of having a high TMB value (10 mutations/megabase) and having received one dose of pembrolizumab, ipilimumab, or nivolumab.

Primary Outcomes•16 patients experienced a partial response (AR = 0.47) and 6 of these patients experienced a complete response (AR = 0.17)

Secondary Outcomes•Absolute risk with prior TMB information (PR 0.43, CR: 0.17)•Absolute risks for monotherapy (PR: 0.375, CR: 0.125) vs combination therapy (PR: 0.556, CR: 0.375)•Average line of treatment for TF, PR, and CR were 2.24, 2, and 1.83 respectively.

Discussion

Studies like KEYNOTE-158 found a significant correlation between high TMB and improved clinical outcomes in patients receiving checkpoint inhibitors. However, in this cohort of patients high TMB status was not a good predictor of therapeutic success compared to the data presented in KEYNOTE-001, CHECKMATE-057, OAK, or PACIFIC. While there are limitations associated with the sample size, the data support that checkpoint therapy benefits patients when it is used earlier in their treatment course and combined with other treatments. Further exploration is required to determine the most appropriate cut point for calling a patient TMB high as well as how TMB and PD-L1 predict response to specific therapies.

Citation Format: Khai Nguyen, Bing Xu, Rachel Elsey, Tobias Meissner, Casey Williams. A single-center retrospective review assessing the use of tumor mutation burden as a predictor of therapeutic success in patients receiving immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 371.

Cell morphology-based machine learning models for human cell state classification

Herein, we implement and access machine learning architectures to ascertain models that differentiate healthy from apoptotic cells using exclusively forward (FSC) and side (SSC) scatter flow cytometry information. To generate training data, colorectal cancer HCT116 cells were subjected to miR-34a treatment and then classified using a conventional Annexin V/propidium iodide (PI)-staining assay. The apoptotic cells were defined as Annexin V-positive cells, which include early and late apoptotic cells, necrotic cells, as well as other dying or dead cells. In addition to fluorescent signal, we collected cell size and granularity information from the FSC and SSC parameters. Both parameters are subdivided into area, height, and width, thus providing a total of six numerical features that informed and trained our models. A collection of logistical regression, random forest, k-nearest neighbor, multilayer perceptron, and support vector machine was trained and tested for classification performance in predicting cell states using only the six aforementioned numerical features. Out of 1046 candidate models, a multilayer perceptron was chosen with 0.91 live precision, 0.93 live recall, 0.92 live f value and 0.97 live area under the ROC curve when applied on standardized data. We discuss and highlight differences in classifier performance and compare the results to the standard practice of forward and side scatter gating, typically performed to select cells based on size and/or complexity. We demonstrate that our model, a ready-to-use module for any flow cytometry-based analysis, can provide automated, reliable, and stain-free classification of healthy and apoptotic cells using exclusively size and granularity information.

Integrated bioelectronic proton-gated logic elements utilizing nanoscale patterned Nafion

A central endeavour in bioelectronics is the development of logic elements to transduce and process ionic to electronic signals. Motivated by this challenge, we report fully monolithic, nanoscale logic elements featuring n- and p-type nanowires as electronic channels that are proton-gated by electron-beam patterned Nafion. We demonstrate inverter circuits with state-of-the-art ion-to-electron transduction performance giving DC gain exceeding 5 and frequency response up to 2 kHz. A key innovation facilitating the logic integration is a new electron-beam process for patterning Nafion with linewidths down to 125 nm. This process delivers feature sizes compatible with low voltage, fast switching elements. This expands the scope for Nafion as a versatile patternable high-proton-conductivity element for bioelectronics and other applications requiring nanoengineered protonic membranes and electrodes.

Use of Cannabis for Sleep: Patterns of Use Among a Sample of Patients in a Geriatrics Clinic

Cannabis may be useful for treatment of sleep problems in older adults. Little is known about use patterns of cannabis for sleep. We conducted a clinic-based anonymous survey in a geriatrics clinic in La Jolla, CA. Among n=568 surveys, 10% reported recent use (within past 6 months). Among recent users, 30% reported using cannabis for sleep, most finding it helpful. Compared to cannabis users for other conditions, cannabis users for sleep were more likely to use THC containing products (62.5% vs. 32.1%), use cannabis on a daily or weekly basis (76.2% vs. 43.2%), use vape pens (29.2% vs. 6.9%), and to obtain cannabis via a delivery service (33.3% vs. 14.0%) (all p’s<0.05). Only 40% reported their doctor knew about their cannabis use. Our findings suggest sleep is a common reason for using cannabis. Future research should assess how use patterns can result in effective treatment for sleep in older adults. Part of a symposium sponsored by the Sleep, Circadian Rhythms and Aging Interest Group.

Uncoupling gene expression noise along the central dogma using genome engineered human cell lines

Eukaryotic protein synthesis is an inherently stochastic process. This stochasticity stems not only from variations in cell content between cells but also from thermodynamic fluctuations in a single cell. Ultimately, these inherently stochastic processes manifest as noise in gene expression, where even genetically identical cells in the same environment exhibit variation in their protein abundances. In order to elucidate the underlying sources that contribute to gene expression noise, we quantify the contribution of each step within the process of protein synthesis along the central dogma. We uncouple gene expression at the transcriptional, translational, and post-translational level using custom engineered circuits stably integrated in human cells using CRISPR. We provide a generalized framework to approximate intrinsic and extrinsic noise in a population of cells expressing an unbalanced two-reporter system. Our decomposition shows that the majority of intrinsic fluctuations stem from transcription and that coupling the two genes along the central dogma forces the fluctuations to propagate and accumulate along the same path, resulting in increased observed global correlation between the products.

Cannabis: An Emerging Treatment for Common Symptoms in Older Adults

BACKGROUND/OBJECTIVES

Use of cannabis is increasing in a variety of populations in the United States; however, few investigations about how and for what reasons cannabis is used in older populations exist.

DESIGN

Anonymous survey.

SETTING

Geriatrics clinic.

PARTICIPANTS

A total of 568 adults 65 years and older.

INTERVENTION

Not applicable.

MEASUREMENTS

Survey assessing characteristics of cannabis use.

RESULTS

Approximately 15% (N = 83) of survey responders reported using cannabis within the past 3 years. Half (53%) reported using cannabis regularly on a daily or weekly basis, and reported using cannabidiol-only products (46%). The majority (78%) used cannabis for medical purposes only, with the most common targeted conditions/symptoms being pain/arthritis (73%), sleep disturbance (29%), anxiety (24%), and depression (17%). Just over three-quarters reported cannabis "somewhat" or "extremely" helpful in managing one of these conditions, with few adverse effects. Just over half obtained cannabis via a dispensary, and lotions (35%), tinctures (35%), and smoking (30%) were the most common administration forms. Most indicated family members (94%) knew about their cannabis use, about half reported their friends knew, and 41% reported their healthcare provider knowing. Sixty-one percent used cannabis for the first time as older adults (aged ≥61 years), and these users overall engaged in less risky use patterns (e.g., more likely to use for medical purposes, less likely to consume via smoking).

CONCLUSION

Most older adults in the sample initiated cannabis use after the age of 60 years and used it primarily for medical purposes to treat pain, sleep disturbance, anxiety, and/or depression. Cannabis use by older adults is likely to increase due to medical need, favorable legalization, and attitudes.