2D antiscatter grid and scatter sampling based CBCT method for online dose calculations during CBCT guided radiation therapy of pelvis

BACKGROUND

Online dose calculations before the delivery of radiation treatments have applications in dose delivery verification, online adaptation of treatment plans, and simulation-free treatment planning. While dose calculations by directly utilizing CBCT images are desired, dosimetric accuracy can be compromised due to relatively lower HU accuracy in CBCT images.

PURPOSE

In this work, we propose a novel CBCT imaging pipeline to enhance the accuracy of CBCT-based dose calculations in the pelvis region. Our approach aims to improve the HU accuracy in CBCT images, thereby improving the overall accuracy of CBCT-based dose calculations prior to radiation treatment delivery.

METHODS

An in-house developed quantitative CBCT pipeline was implemented to address the CBCT raw data contamination problem. The pipeline combines algorithmic data correction strategies and 2D antiscatter grid-based scatter rejection to achieve high CT number accuracy. To evaluate the effect of the quantitative CBCT pipeline on CBCT-based dose calculations, phantoms mimicking pelvis anatomy were scanned using a linac-mounted CBCT system, and a gold standard multidetector CT used for treatment planning (pCT). A total of 20 intensity-modulated treatment plans were generated for five targets, using 6 and 10 MV flattening filter-free beams, and utilizing small and large pelvis phantom images. For each treatment plan, four different dose calculations were performed using pCT images and three CBCT imaging configurations: quantitative CBCT, clinical CBCT protocol, and a high-performance 1D antiscatter grid (1D ASG). Subsequently, dosimetric accuracy was evaluated for both targets and organs at risk as a function of patient size, target location, beam energy, and CBCT imaging configuration.

RESULTS

When compared to the gold-standard pCT, dosimetric errors in quantitative CBCT-based dose calculations were not significant across all phantom sizes, beam energies, and treatment sites. The largest error observed was 0.6% among all dose volume histogram metrics and evaluated dose calculations. In contrast, dosimetric errors reached up to 7% and 97% in clinical CBCT and high-performance ASG CBCT-based treatment plans, respectively. The largest dosimetric errors were observed in bony targets in the large phantom treated with 6 MV beams. The trends of dosimetric errors in organs at risk were similar to those observed in the targets.

CONCLUSIONS

The proposed quantitative CBCT pipeline has the potential to provide comparable dose calculation accuracy to the gold-standard planning CT in photon radiation therapy for the abdomen and pelvis. These robust dose calculations could eliminate the need for density overrides in CBCT images and enable direct utilization of CBCT images for dose delivery monitoring or online treatment plan adaptations before the delivery of radiation treatments.

Abdominal wall mass resections: single-center closure practices and outcomes following oncologic resections of abdominal wall fascia

PURPOSE

Radical resections for abdominal wall tumors are rare, thus yielding limited data on reconstruction of defects. We describe surgical management and long-term outcomes following radical tumor resection.

METHODS

This was a single-center retrospective review of patients between January 2010 and December 2022. Variables included operative characteristics, wound complications, hernia development, tumor recurrence, and reoperation. A multivariable analysis compared wound morbidity for suture and mesh repairs while adjusting for defect width, fascial closure, and CDC wound class.

RESULTS

120 patients were identified. Mean follow-up was 3.9 ± 3.4 years. Seventy-five (62.5%) of the masses were primary; most commonly desmoid (n = 25) and endometrioma (n = 27). Forty-five masses were metastases. Mean tumor width was 6.2 ± 3.4 cm; mean defect width was 8.1 ± 4.1 cm. Sixty-one patients (50.8%) had mesh placed, with variation in technique. Postoperative CT scans were available for 88 (73.3%) patients. Forty SSOs (33.3%), 11 SSIs (9.2%), and 18 (15%) SSOPIs occurred within 30 days. On multivariable analysis, increased defect width was associated with SSOPI (OR 1.17, p = 0.041) and CDC wound class II-III was associated with SSI (OR 8.38 and 49.1, p < 0.05) and SSOPI (OR 5.77 and 17.4, p < 0.05); mesh was not associated with these outcomes. Seven patients (5.8%) underwent 30-day reoperations and 35 (20.8%) required additional operations after 30 days. Thirteen percent developed abdominal wall (n = 8) or intra-abdominal tumor recurrence (n = 8) requiring reoperation. Twenty-seven (22.5%) patients developed hernias with a mean fascial defect width of 9.8 ± 7.2 cm.

CONCLUSION

Abdominal wall mass resections are morbid, often contaminated cases with high postoperative complication rates. Risks and benefits of mesh implantation should be tailored on an individual basis.

Expansion of Telestroke Coverage in Community Hospitals: Unifying Stroke Care and Reducing Transfer Rate

OBJECTIVE

Telestroke (TS) service has been shown to improve stroke diagnosis timing and accuracy, facilitate treatment decisions, and decrease interfacility transfers. Expanding TS service to inpatient units at the community hospital provides an opportunity to follow up on stroke patients and optimize medical management. This study examines the outcome of expanding TS coverage from acute emergency room triage to incorporate inpatient consultation.

METHODS

We studied the effect of expanding TS to inpatient consultation service at 19 regional hospitals affiliated with Promedica Stroke Network. We analyzed data pre- and post-TS expansion. We reviewed changes in TS utilization, admission rate, thrombolytic therapy, patient transfer rate, and diagnosis accuracy.

RESULTS

Between January 2018 and June 2022, a total of 9,756 patients were evaluated in our stroke network (4,705 in pre- and 5,051 in the post-TS expansion). In the post-TS expansion period, stroke patients' admission at the spoke hospital increased from 18/month to 40/month, and for TIA from 11/month to 16/month. TS cart use increased from 12% to 35.2%. Patient transfers to hub hospital decreased by 31%. TS service expansion did not affect intravenous thrombolytic therapy rate or door-to-needle time. There was no difference in length of stay or readmission rate, and the patients at the spoke hospitals had a higher rate of home discharge 57.38% compared with 52.58% at hub hospital.

INTERPRETATION

Telestroke service expansion to inpatient units helped decrease transfers and retain patients in their communities, increased stroke and TIA diagnosis accuracy, and did not compromise patients' hospitalization or outcome. ANN NEUROL 2024;95:576-582.

Pediatric Outcomes of Emergency Medical Services Non-Transport Before and During the COVID-19 Pandemic

Introduction

Pediatric patients account for 6-10% of emergency medical services (EMS) activations in the United States. Approximately 30% of these children are not transported to an emergency department (ED). Adult data in the literature reports higher hospitalization and complications following non-transport. Few studies discuss epidemiology and characteristics of pediatric non-transport; however, data on outcome is limited. Our primary aim was to determine outcomes of non-transported children within our urban EMS system before and during the COVID-19 pandemic. Our secondary objective was to explore reasons for non-transport.

Methods

This was a prospective, descriptive pilot study. We compared EMS data for September 2019 (pre-COVID-19) to September 2020 (pandemic). Included were children aged 0-17 years who activated EMS and did not receive transport to the primary hospital for the EMS capture area. We defined outcomes as repeat EMS activation, ED visits, and hospital admissions, all within 72 hours. Data was obtained via electronic capture. We used descriptive statistics to analyze our data, chi square for categorical data, stepwise logistic regression, and univariate logistic regression to test for association of covariates with non-transport.

Results

There were 1,089 pediatric EMS activations in September 2019 and 780 in September 2020. Non-transport occurred in 633 (58%) in September 2019 and 412 (53%) in September 2020. Emergency medical services was reactivated within 72 hours in the following: 9/633 (1.4%) in 2019; and 5/412 (1.2%) in 2020 (P = 0.77). Visits to the ED occurred in 57/633 (9%) in 2019 and 42/412 (10%) in 2020 (P = 0.53). Hospital admissions occurred in 10/633 (1.5%) in 2019 and 4/412 (0.97%) in 2020 (P = 0.19). One non-transported patient was admitted to the intensive care unit in September 2020 (<1%) and survived. Hispanic ethnicity, age >12 years, and fever were associated with repeat EMS activation. The most common reason for non-transport in both study periods was that the parent felt an ambulance was not necessary (47%).

Conclusion

In our system, non-transport of pediatric patients occurred in >50% of EMS activations with no significant adverse outcome. Age >12 years, fever, and Hispanic ethnicity were more common in repeated EMS activations. The most common reason for non-transport was parents feeling it was not necessary. Future studies are needed to develop reliable EMS guidelines for pediatric non-transport.

Taking identity-by-descent analysis into the wild: Estimating realized relatedness in free-ranging macaques

Biological relatedness is a key consideration in studies of behavior, population structure, and trait evolution. Except for parent-offspring dyads, pedigrees capture relatedness imperfectly. The number and length of DNA segments that are identical-by-descent (IBD) yield the most precise estimates of relatedness. Here, we leverage novel methods for estimating locus-specific IBD from low coverage whole genome resequencing data to demonstrate the feasibility and value of resolving fine-scaled gradients of relatedness in free-living animals. Using primarily 4-6× coverage data from a rhesus macaque (Macaca mulatta) population with available long-term pedigree data, we show that we can call the number and length of IBD segments across the genome with high accuracy even at 0.5× coverage. The resulting estimates demonstrate substantial variation in genetic relatedness within kin classes, leading to overlapping distributions between kin classes. They identify cryptic genetic relatives that are not represented in the pedigree and reveal elevated recombination rates in females relative to males, which allows us to discriminate maternal and paternal kin using genotype data alone. Our findings represent a breakthrough in the ability to understand the predictors and consequences of genetic relatedness in natural populations, contributing to our understanding of a fundamental component of population structure in the wild.

A 2D antiscatter grid and scatter sampling based CBCT method for online dose calculations during CBCT guided radiation therapy of pelvis

Online dose calculations before radiation treatment have applications in dose delivery verification, plan adaptation, and treatment planning. We propose a novel CBCT imaging pipeline to enhance accuracy. Our approach aims to improve HU accuracy in CBCT images for more precise dose calculations. A quantitative CBCT pipeline was implemented, combining data correction strategies and scatter rejection, achieving high CT number accuracy. We evaluated the pipeline's effect using pelvis anatomy phantoms and found that dosimetric errors in quantitative CBCT-based dose calculations were minimal. In contrast, clinical CBCT and high-performance ASG CBCT-based plans showed significant errors. The proposed quantitative CBCT pipeline offers comparable dose calculation accuracy to the gold-standard planning CT, eliminating the need for density overrides and enabling precise dose delivery monitoring or online plan adaptations in radiation therapy.

Arrhythmic Effects of Cannabis in Ischemic Heart Disease

Rationale: Cannabis use is increasing worldwide, especially among older individuals at risk for chronic ischemic heart disease (IHD). However, little is known about the arrhythmic effects of cannabis use in IHD. Accordingly, we prospectively assessed the relationship between cannabis use, heart rate (HR), and arrhythmias in healthy age-matched controls and subjects with IHD. Methods: Healthy controls (n=37, 57% men) and subjects with IHD (myocardial infarction ≥3 months ago; n=24, 58% men) who used cannabis wore a Zio® (iRhythm Technologies) monitor for 14 days. Noncannabis using ischemic subjects (n=35, 51% males) wore Zio monitors for standard clinical indications. Baseline HR was compared with average HR measured for 4 h following consumption and changes in HR and frequency of arrhythmias were correlated with cannabis use. Results: In controls, HR increased 20 min (4.99±6.7 bpm, p=0.08) after use, then declined 4 h following use (-7.4±7.7, p<0.001). Conversely, subjects with IHD showed minimal HR increase (1.6±3.9 bpm) and blunted HR decline (-3.4±5.6 bpm, p<0.001). Supraventricular tachycardia (SVT) (29.7% vs. 58.3%; p=0.04) and nonsustained ventricular tachycardia (NSVT) (5.6% vs. 47.8%, p=0.01) were the most frequently occurring arrhythmias in controls and IHD subjects, respectively. Incidence of SVT decreased as cannabis use increased in both groups. Conversely, NSVT tended to increase with increased use in controls, and was significantly more prevalent in IHD. However, overall arrhythmia burden did not differ between cannabis users and nonusers with IHD. Conclusion: Our findings demonstrate that chronic cannabis use is associated with only mild HR changes, which are blunted in IHD. In addition, our data suggest that among cannabis users, arrhythmias are more frequent in IHD subjects that in healthy subjects.

Yttrium-90 Activity Quantification in PET/CT-Guided Biopsy Specimens from Colorectal Hepatic Metastases Immediately after Transarterial Radioembolization Using Micro-CT and Autoradiography

PURPOSE

To evaluate the yttrium-90 (90Y) activity distribution in biopsy tissue samples of the treated liver to quantify the dose with higher spatial resolution than positron emission tomography (PET) for accurate investigation of correlations with microscopic biological effects and to evaluate the radiation safety of this procedure.

MATERIALS AND METHODS

Eighty-six core biopsy specimens were obtained from 18 colorectal liver metastases (CLMs) immediately after 90Y transarterial radioembolization (TARE) with either resin or glass microspheres using real-time 90Y PET/CT guidance in 17 patients. A high-resolution micro-computed tomography (micro-CT) scanner was used to image the microspheres in part of the specimens and allow quantification of 90Y activity directly or by calibrating autoradiography (ARG) images. The mean doses to the specimens were derived from the measured specimens' activity concentrations and from the PET/CT scan at the location of the biopsy needle tip for all cases. Staff exposures were monitored.

RESULTS

The mean measured 90Y activity concentration in the CLM specimens at time of infusion was 2.4 ± 4.0 MBq/mL. The biopsies revealed higher activity heterogeneity than PET. Radiation exposure to the interventional radiologists during post-TARE biopsy procedures was minimal.

CONCLUSIONS

Counting the microspheres and measuring the activity in biopsy specimens obtained after TARE are safe and feasible and can be used to determine the administered activity and its distribution in the treated and biopsied liver tissue with high spatial resolution. Complementing 90Y PET/CT imaging with this approach promises to yield more accurate direct correlation of histopathological changes and absorbed dose in the examined specimens.

Frequency-Dependent Squeezed Vacuum Source for the Advanced Virgo Gravitational-Wave Detector

In this Letter, we present the design and performance of the frequency-dependent squeezed vacuum source that will be used for the broadband quantum noise reduction of the Advanced Virgo Plus gravitational-wave detector in the upcoming observation run. The frequency-dependent squeezed field is generated by a phase rotation of a frequency-independent squeezed state through a 285 m long, high-finesse, near-detuned optical resonator. With about 8.5 dB of generated squeezing, up to 5.6 dB of quantum noise suppression has been measured at high frequency while close to the filter cavity resonance frequency, the intracavity losses limit this value to about 2 dB. Frequency-dependent squeezing is produced with a rotation frequency stability of about 6 Hz rms, which is maintained over the long term. The achieved results fulfill the frequency dependent squeezed vacuum source requirements for Advanced Virgo Plus. With the current squeezing source, considering also the estimated squeezing degradation induced by the interferometer, we expect a reduction of the quantum shot noise and radiation pressure noise of up to 4.5 dB and 2 dB, respectively.

Intention to vaccinate against COVID-19 and potential outreach strategies for a residential research university in Northeastern Ohio

INTRODUCTION

A university's understanding of student, faculty, and staff members' intention to vaccinate against COVID-19 has been vital in returning safely to in-person education, research, and engagement with communities and professions. We employed a novel survey to describe intentions across subpopulations of one campus and consider key issues in their rationales for intentions and hesitancies.

MATERIALS AND METHODS

1,077 surveys based on Theory of Planned Behavior were completed from randomly selected pools of undergraduate students, graduate students, part-time faculty, full-time faculty, and staff. Chi-Squared Automated Interaction Detection algorithm analysis provided paths for evaluation.

RESULTS AND DISCUSSION

83 percent of respondents said they would receive the vaccine at their first opportunity, while 5 percent said they would never get the vaccine; the remaining 12 percent wanted more evidence before getting the vaccine. Findings included negative health perceptions of the vaccine, misinformation on the process, as well as negative rhetorical responses differentiated between political partisanship and membership within the campus community, eg, faculty, staff, or student.

IMPLICATIONS

Universities seeking to raise campus vaccination rates should concentrate limited resources on the largest populations with the most opportunity to vaccinate. In this study, newer students, with conservative political views, represented a population of opportunity. Their formative beliefs may be influenced by messaging and in collaboration with students' personal physician and/or friend groups. A theory-based approach leads to focused efforts for safer campuses and resumption/continuation of face-to-face interactions for students, faculty, and staff.

The origins and functional effects of postzygotic mutations throughout the human life span

Postzygotic mutations (PZMs) begin to accrue in the human genome immediately after fertilization, but how and when PZMs affect development and lifetime health remain unclear. To study the origins and functional consequences of PZMs, we generated a multitissue atlas of PZMs spanning 54 tissue and cell types from 948 donors. Nearly half the variation in mutation burden among tissue samples can be explained by measured technical and biological effects, and 9% can be attributed to donor-specific effects. Through phylogenetic reconstruction of PZMs, we found that their type and predicted functional impact vary during prenatal development, across tissues, and through the germ cell life cycle. Thus, methods for interpreting effects across the body and the life span are needed to fully understand the consequences of genetic variants.

Z-REX: shepherding reactive electrophiles to specific proteins expressed tissue specifically or ubiquitously, and recording the resultant functional electrophile-induced redox responses in larval fish

This Protocol Extension describes the adaptation of an existing Protocol detailing the use of targetable reactive electrophiles and oxidants, an on-demand redox targeting toolset in cultured cells. The adaptation described here is for use of reactive electrophiles and oxidants technologies in live zebrafish embryos (Z-REX). Zebrafish embryos expressing a Halo-tagged protein of interest (POI)-either ubiquitously or tissue specifically-are treated with a HaloTag-specific small-molecule probe housing a photocaged reactive electrophile (either natural electrophiles or synthetic electrophilic drug-like fragments). The reactive electrophile is then photouncaged at a user-defined time, enabling proximity-assisted electrophile-modification of the POI. Functional and phenotypic ramifications of POI-specific modification can then be monitored, by coupling to standard downstream assays, such as click chemistry-based POI-labeling and target-occupancy quantification; immunofluorescence or live imaging; RNA-sequencing and real-time quantitative polymerase chain reaction analyses of downstream-transcript modulations. Transient expression of requisite Halo-POI in zebrafish embryos is achieved by messenger RNA injection. Procedures associated with generation of transgenic zebrafish expressing a tissue-specific Halo-POI are also described. The Z-REX experiments can be completed in <1 week using standard techniques. To successfully execute Z-REX, researchers should have basic skills in fish husbandry, imaging and pathway analysis. Experience with protein or proteome manipulation is useful. This Protocol Extension is aimed at helping chemical biologists study precision redox events in a model organism and fish biologists perform redox chemical biology.

Surgical stabilization of rib fracture patients versus nonoperative controls treated by a multidisciplinary team in a single institution

Introduction

Despite promising evidence, surgical stabilization of rib fractures (SSRF) is not ubiquitously offered in all trauma centers. Some centers struggle with patient selection while some struggle due to surgeon comfort with the technique. To address this issue, our trauma center developed a multidisciplinary SSRF approach between orthopedic and trauma surgery.

Methods

This retrospective study compared 43 patients who underwent SSRF at a level 1 trauma center with 43 nonoperatively managed controls. Our study Indications were flail chest with >3 segments; non-flail with severe, bi-cortical displacement of >3 contiguous segments. Main outcome measures included mortality, ICU duration, hospital stay LOS, rates of ventilator-associated pneumonia (VAP) and ventilator days.

Results

Results of SSRF included decreases in mortality (2% vs 16.3%; p = 0.03) and in ICU duration. Patients with SSRF had a significantly shorter duration in the ICU than the nonoperative group (8.72 vs 14 days; p = 0.013) but a similar hospital duration (LOS mean, 12.81 vs 15.2; p = 0.29). Less patients in the SSRF group developed VAP but the difference was not significant (2% vs 14%, p = 0.055).

Discussion

SSRF patient outcomes supported prior evidence. The tandem approach had benefits as surgeons were able to leverage skills and expertise, increase collaboration between services, and complete more difficult reconstructions. Our experience may serve as a model for trauma centers interested in starting a new program or enhancing current service offerings.

Varying failure criteria on performance validity tests influences interpretation of cognitive outcomes

OBJECTIVE

The present study examined the effects of applying various performance validity tests (PVT) failure criteria on the relationship between cognitive outcomes and posttraumatic stress (PTS) symptomology.

METHOD

One hundred and ninety-nine veterans with a history of mild traumatic brain injury referred for clinical evaluation completed cognitive tests, PVTs, and self-report measures of PTS symptoms and symptom exaggeration. Normative T scores of select cognitive tests were averaged into memory, attention/processing speed, and executive functioning composites. Separate one way analyses of variance assessed differences among high PTS (n = 140) versus low PTS (n = 59) groups and were repeated excluding participants based on varying combinations of PVT failure criteria.

RESULTS

When no PVTs were considered, the high PTS group demonstrated worse performance across all three cognitive domains. Excluding those who failed two or more stand-alone, or two or more embedded validity measures resulted in group differences across all cognitive composites. When participants were excluded based on failure of any one embedded and any one stand-alone PVT measure combined, the high PTS group performed worse on the executive functioning and attention/processing speed composites. The remaining three proposed methods to control for performance validity resulted in null PTS-cognition relationships. Results remained largely consistent after controlling for symptom exaggeration.

CONCLUSIONS

Methods of defining PVT failure can greatly influence differences in cognitive function between groups defined by PTS symptom levels. Findings highlight the importance of considering performance validity when interpreting cognitive data and warrant future investigation of PVT failure criteria in other conditions. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Diverse monogenic subforms of human spermatogenic failure

Non-obstructive azoospermia (NOA) is the most severe form of male infertility and typically incurable. Defining the genetic basis of NOA has proven challenging, and the most advanced classification of NOA subforms is not based on genetics, but simple description of testis histology. In this study, we exome-sequenced over 1000 clinically diagnosed NOA cases and identified a plausible recessive Mendelian cause in 20%. We find further support for 21 genes in a 2-stage burden test with 2072 cases and 11,587 fertile controls. The disrupted genes are primarily on the autosomes, enriched for undescribed human "knockouts", and, for the most part, have yet to be linked to a Mendelian trait. Integration with single-cell RNA sequencing data shows that azoospermia genes can be grouped into molecular subforms with synchronized expression patterns, and analogs of these subforms exist in mice. This analysis framework identifies groups of genes with known roles in spermatogenesis but also reveals unrecognized subforms, such as a set of genes expressed across mitotic divisions of differentiating spermatogonia. Our findings highlight NOA as an understudied Mendelian disorder and provide a conceptual structure for organizing the complex genetics of male infertility, which may provide a rational basis for disease classification.

Do Storage Conditions Affect Collected Cookstove Emission Samples? Implications for Field Studies

Cookstove emissions are a significant source of indoor air pollution in developing countries and rural communities world-wide. Considering that many research sites for evaluating cookstove emissions and interventions are remote and require potentially lengthy periods of particulate matter (PM) filter sample storage in sub-optimal conditions (e.g., lack of cold storage), an important question is whether samples collected in the field are stable over time. To investigate this, red oak was burned in a natural-draft stove, and fine PM (PM2.5) was collected on polytetrafluoroethylene filters. Filters were stored at either ambient temperature or more optimal conditions (-20°C or -80°C) for up to 3 months and extracted. The effects of storage temperature and length on stability were evaluated for measurements of extractable organic matter (EOM), PM2.5, and polycyclic aromatic compound (PAC) levels in the filter extracts. A parallel, controlled laboratory condition was also evaluated to further explore sources of variability. In general, PM2.5 and EOM in both simulated field and laboratory samples were similar regardless of the storage condition or duration. The extracts were also analyzed by gas chromatography to quantify 22 PACs and determine similarities and/or differences between the conditions. PAC levels were a more sensitive stability measure in differentiating between storage conditions. The findings suggest that measurements are relatively consistent across storage duration/temperatures for filter samples with relatively low EOM levels. This study aims to inform protocols and filter storage procedures for exposure and intervention research conducted in low- and middle-income countries where studies may be budget- and infrastructure-limited.

Optimizing Detection of MEC-Mediated Methicillin Resistance in Coagulase Negative Staphylococcus Species

Introduction/Objective

Parenteral therapy for invasive staphylococcal infections often comprises lipo/glycopeptides for methicillin resistant (MR) organisms, with extended spectrum penicillins reserved for those confirmed as methicillin susceptible (MS). While phenotypic antimicrobial susceptibility testing (AST) using cefoxitin has high accuracy for differentiating MR/MS for S. aureus, the same, simple approach does not reliably distinguish resistance among all coagulase negative Staphylococcus species (CoNS). As such, clinicians may work under an assumption that MS CoNS cannot be reliably predicted by laboratories, leading to lipo/glycopeptide therapeutic use for invasive infections caused by both MR and MS isolates. To better inform laboratory practice, this study aimed to establish the accuracy of multiple phenotypic and genotypic tests for differentiation of MR/MS among commonly recovered CoNS species producing invasive infections.

Methods/Case Report

A convenience sample of 155 unique invasive CoNS isolates with historic Vitek 2 and/or disc diffusion (DD) AST results (~50% MR) were retrieved from frozen storage and tested by: (1) cefoxitin and oxacillin DD, (2) a lateral flow immunoassay for PBP2a without beta-lactam induction, and (3) a lab-developed PCR for mecA. A commercial real-time PCR for mecA/C was also employed for a subset of isolates.

Results (if a Case Study enter NA)

A total of 144 isolates belonging to 11 taxa were evaluated by all tests after accounting for missing, non-viable, and incorrectly cataloged isolates. Using PCR mecA/C detection as the reference standard, categorical agreement for MR/MS status was 95.5% (127/133) for original Vitek GP75 results, 98.6% (142/144) for DD interpreted using updated, species-specific CLSI guidelines, and 100% (144/144) for the lateral flow PBP2a assay. Six MR isolates from five different taxa that were repeatedly mecA-negative by lab-developed PCR confirmed as mecA/C-positive by a commercial assay.

Conclusion

Although all methods evaluated distinguish MR/MS CoNS with sufficient accuracy, definitive determination is best achieved using off-label/lab-developed PCR for mec or lateral flow immunoassay for PBP2a.

Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M_{⊙} and 1.0  M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200]  Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M_{⊙}<m_{PBH}<1.0  M_{⊙} is f_{PBH}≡Ω_{PBH}/Ω_{DM}≲6%. This improves existing constraints on primordial black hole abundance by a factor of ∼3. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_{min}=1  M_{⊙}, where f_{DBH}≡Ω_{DBH}/Ω_{DM}≲0.003%. These are the first constraints placed on dissipative dark models by subsolar-mass analyses.

Ageism in healthcare technology: the older patients’ aspirations for improved online accessibility

Objective

To identify concerns, barriers and facilitators impacting the use of patient portals by older patients as well as desired features in future updates.

Materials and Methods

This is a cross-sectional study consisting of 2 focus group discussions culminating in an anonymous survey administered to women who were 65 years and older receiving urogynecologic care in Northwest Ohio.

Results

Of the 205 women surveyed (91% response rate), providers and healthcare systems play the primary 2 roles (73% and 69%, respectively) in facilitating patients’ use of patient portal systems and telehealth applications. Barriers to use revolved around technical difficulties (50%), privacy concerns (45%), and cost of technology (24%). The most important features desired were the ability to modify the text size within the application (47%) and an intuitive, simple interface (46%). Additional assistance for navigating technical challenges was suggested, specifically set-up of accounts (36%), saving and sharing information with caregivers (35%), and sign-in and navigation of portals (32%).

Conclusion

The paucity of age-aligned medical access software and products may lead to worsening of digital exclusion and disparities in healthcare. Portal application developers and healthcare systems must advance efforts that consider the needs of those who may be older when designing patient portals.

Epigenetics and first-episode psychosis: A systematic review

BACKGROUND

Schizophrenia has a large disease burden globally. Early intervention in psychosis, and therefore a decreased duration of untreated psychosis, has a positive clinical impact. There are several recognized risk factors for psychosis, including trauma history and substance use. This systematic review examined the literature for studies related to epigenetic changes in first-episode psychosis, with the goal of identifying future research directions.

METHODS

A literature review was conducted from inception to October 3, 2021 using MedLine/PubMed, Web of Science, and PsycInfo searches with the keywords ("first-episode schizophrenia" OR "first-episode psychosis" OR "drug-naive schizophrenia" OR "drug-naive psychosis") AND (epigenetic OR methylation OR hydroxymethylation OR "histone modification" OR "miRNA") as well as a search of the bibliography of the identified papers.

RESULTS

Seventeen studies that examined various portions of the genome were included in this systematic review. There were two studies that showed hypomethylation at the LINE-1 portion of the genome and two that showed hypermethylation at LINE-1. Additionally, two studies showed hypomethylation specifically at the GRIN2B promoter (part of LINE-1).

CONCLUSIONS

Although sample sizes were small, these studies provide evidence for epigenetic alterations in early psychosis. Further research in this area is warranted for more definitive epigenetic correlations.

575. Local Experience of Breakthrough SARS-CoV-2 Infections After Full Vaccination

Background

SARS-CoV-2 the etiology of COVID-19 has caused more than 33 million cases and almost 600,000 deaths in the United States alone. Vaccination is a vital tool in controlling the pandemic. With accelerated infection rates in various parts of the world, the incidence of variants has risen and threatens to set back the long sought after immunity, provided by available vaccines. The objective of this study was to evaluate the breakthrough infection rate after complete vaccination, in Sangamon County, with a rural and urban population of 195,000 in Central Illinois.

Methods

Data regarding breakthrough infections collected from the Sangamon County Department of Public Health, included the total number of infections, time after vaccination, age range of those infected and the type of vaccine used. Complete vaccination was defined as 14 days after the single dose of Johnson & Johnson/Janssen or the second dose of Pfizer-BioNTech or Moderna Inc. vaccine.

Results

The number of fully vaccinated individuals at the time of writing of this study was 87,086 which corresponded to 44.58 % of the total population. The breakthrough infection percentage was calculated as 0.036%. The mean time after vaccination to infection was 49.13 days with a standard deviation of 23.28.

Conclusion

Breakthrough infections among fully vaccinated individuals in our county, have been quite rare, which points to the high efficacy of the vaccines. A complex number of factors likely contribute to this including virus-related factors i.e. variant forms and specific patient-related factors which are not a part of this study. The afore-mentioned high efficacy rate of the vaccines provides further justification, to continue to pursue a persistent vaccination strategy to mitigate the effects of the SARS-CoV-2 virus.

Disclosures

All Authors: No reported disclosures

Pharmacological effects of ex vivo mesenchymal stem cell immunotherapy in patients with acute kidney injury and underlying systemic inflammation

Mesenchymal stem cells (MSCs) have natural immunoregulatory functions that have been explored for medicinal use as a cell therapy with limited success. A phase Ib study was conducted to evaluate the safety and immunoregulatory mechanism of action of MSCs using a novel ex vivo product (SBI-101) to preserve cell activity in patients with severe acute kidney injury. Pharmacological data demonstrated MSC-secreted factor activity that was associated with anti-inflammatory signatures in the molecular and cellular profiling of patient blood. Systems biology analysis captured multicompartment effects consistent with immune reprogramming and kidney tissue repair. Although the study was not powered for clinical efficacy, these results are supportive of the therapeutic hypothesis, namely, that treatment with SBI-101 elicits an immunotherapeutic response that triggers an accelerated phenotypic switch from tissue injury to tissue repair. Ex vivo administration of MSCs, with increased power of testing, is a potential new biological delivery paradigm that assures sustained MSC activity and immunomodulation.

Metabolic heterogeneous zone assessed by 18 FDG-PET is predictive of postablation mortality in patients with ventricular tachycardia

PURPOSE

We sought to study the predictive value of the metabolic heterogeneous zone (HZ) as determined by ¹⁸ Fluorodeoxyglucose (¹⁸ FDG) positron emission tomography (PET) viability studies in ventricular tachycardia (VT) patients.

METHODS

PET studies utilizing ⁸² Rubidium (⁸² Rb) tracer for perfusion and ¹⁸ FDG tracer for viability were analyzed using PMOD (PMOD Technologies) and further analyzed using 684-segment plots. ¹⁸ FDG uptake was normalized to the area with maximal perfusion on the rest ⁸² Rb study. Metabolic scar, HZ, and healthy segments were defined with perfusion-normalized ¹⁸ FDG uptake between 0%-50%, 50%-70%, and >70%, respectively.

RESULTS

Thirty-four VT patients (age, 63 ± 12 years) were evaluated with ¹⁸ FDG-PET viability study. Most (n = 31) patients underwent VT ablation. Patients were categorized to HZ < median versus HZ ≥ median based on a median HZ area size of 21.0 cm² . HZ size was significantly larger in the deceased group than the alive group (35.2 cm² vs. 18.1 cm² , p = .01). Deaths were significantly higher in HZ ≥ 21 cm² group than HZ < 21 cm² group (58.8% vs. 11.8%, p = .005). Survival analysis showed significantly higher mortality in the HZ ≥ 21 cm² group than the HZ < 21 cm² group (HR = 4.1, 95% CI: 1.3-12.6, p = .016). In a multivariable analysis, HZ was found to be an independent predictor for all-cause mortality (HR = 1.07, 95% CI: 1.02-1.12, p = .01) CONCLUSIONS: Increased HZ size of myocardium was associated with increased mortality. Metabolic HZ quantification may be of value in risk stratification and management of ischemic and nonischemic patients with VT.

Neural dynamics of semantic categorization in semantic variant of primary progressive aphasia

Semantic representations are processed along a posterior-to-anterior gradient reflecting a shift from perceptual (e.g., it has eight legs) to conceptual (e.g., venomous spiders are rare) information. One critical region is the anterior temporal lobe (ATL): patients with semantic variant primary progressive aphasia (svPPA), a clinical syndrome associated with ATL neurodegeneration, manifest a deep loss of semantic knowledge. We test the hypothesis that svPPA patients perform semantic tasks by over-recruiting areas implicated in perceptual processing. We compared MEG recordings of svPPA patients and healthy controls during a categorization task. While behavioral performance did not differ, svPPA patients showed indications of greater activation over bilateral occipital cortices and superior temporal gyrus, and inconsistent engagement of frontal regions. These findings suggest a pervasive reorganization of brain networks in response to ATL neurodegeneration: the loss of this critical hub leads to a dysregulated (semantic) control system, and defective semantic representations are seemingly compensated via enhanced perceptual processing.

Disruption of a ∼23-24 nucleotide small RNA pathway elevates DNA damage responses in Tetrahymena thermophila

Endogenous RNA interference (RNAi) pathways regulate a wide range of cellular processes in diverse eukaryotes, yet in the ciliated eukaryote, Tetrahymena thermophila, the cellular purpose of RNAi pathways that generate ∼23–24 nucleotide (nt) small (s)RNAs has remained unknown. Here, we investigated the phenotypic and gene expression impacts on vegetatively growing cells when genes involved in ∼23–24 nt sRNA biogenesis are disrupted. We observed slower proliferation and increased expression of genes involved in DNA metabolism and chromosome organization and maintenance in sRNA biogenesis mutants RSP1Δ, RDN2Δ, and RDF2Δ. In addition, RSP1Δ and RDN2Δ cells frequently exhibited enlarged chromatin extrusion bodies, which are nonnuclear, DNA-containing structures that may be akin to mammalian micronuclei. Expression of homologous recombination factor Rad51 was specifically elevated in RSP1Δ and RDN2Δ strains, with Rad51 and double-stranded DNA break marker γ-H2A.X localized to discrete macronuclear foci. In addition, an increase in Rad51 and γ-H2A.X foci was also found in knockouts of TWI8, a macronucleus-localized PIWI protein. Together, our findings suggest that an evolutionarily conserved role for RNAi pathways in maintaining genome integrity may be extended even to the early branching eukaryotic lineage that gave rise to Tetrahymena thermophila.

263 Airway, Voice and Swallow Outcomes Following Endotracheal Intubation and Mechanical Ventilation For COVID-19 Pneumonitis: Preliminary Results of a Prospective Cohort Study

Introduction

The COVID-19 pandemic has placed exceptional demands on Intensive Care Units (ICU) across the world – particularly requiring patients to be intubated and mechanically ventilated. Laryngeal injury following intubation is a common occurrence, therefore this study aims to analyse airway, voice, and swallow (AVS) outcomes of patients intubated for COVID-19 pneumonitis and compares it to intubated non-COVID-19 respiratory patients and other ICU admissions.

Method

We collected data from inpatient records, and follow-up clinics on intubated adult patients discharged from a tertiary care hospital ICU between 01/03/20 and 30/04/20. Patients were assessed with the AVS Scale, Voice Handicap Index-10 (VHI-10), and Eating Assessment Tool-10 (EAT-10).

Results

86 patients were admitted with COVID-19 pneumonitis, 17 patients were admitted with non-COVID-19 respiratory failure, and 26 patients were admitted with a non-respiratory diagnosis.

The COVID-19 cohort demonstrated higher rates of AVS difficulties (airway 59% vs 44% and 31%, voice 40% vs 19% and 19%, swallow 21% vs 6% and 12%). VHI-10 and EAT-10 scores showed no significant differences between groups.

Conclusions

Patients intubated for COVID-19 pneumonitis reported higher rates of AVS difficulties against non-COVID-19 reasons for intubation. Robust prospective screening protocols are essential to improving patient outcomes by highlighting and therefore managing laryngological sequelae that occur following intubation.

Evaluation of scatter rejection and correction performance of 2D antiscatter grids in cone beam computed tomography

PURPOSE

We have been investigating two-dimensional (2D) antiscatter grids (2D ASGs) to reduce scatter fluence and improve image quality in cone beam computed tomography (CBCT). In this work, two different aspects of 2D ASGs, their scatter rejection and correction capability, were investigated in CBCT experiments. To correct residual scatter transmitted through the 2D ASG, it was used as a scatter measurement device with a novel method: grid-based scatter sampling.

METHODS

Three focused 2D ASG prototypes with grid ratios of 8, 12, and 16 were developed for linac-mounted offset detector CBCT geometry. In the first phase, 2D ASGs were used as a scatter rejection device, and the effect of grid ratio on CT number accuracy and contrast-to-noise ratio (CNR) evaluated in CBCT images. In the second phase, a grid-based scatter sampling method which exploits the signal modulation characteristics of the 2D ASG's septal shadows to measure and correct residual scatter transmitted through the grid was implemented. To evaluate CT number accuracy, the percent change in CT numbers was measured by changing the phantom from head to pelvis size and configuration.

RESULTS

When 2D ASG was used as a scatter rejection device, CT number accuracy increased and the CT number variation due to change in phantom dimensions was reduced from 23% to 2-6%. A grid ratio of 16 yielded the lowest CT number variation. All three 2D ASGs yielded improvement in CNR, up to a factor of two in pelvis-sized phantoms. When 2D ASG prototypes were used for both scatter rejection and correction, CT number variations were reduced further, to 1.3-2.6%. In comparisons with a clinical CBCT system and a high-performance radiographic ASG, 2D ASG provided higher CT number accuracy under the same imaging conditions.

CONCLUSIONS

When 2D ASG is used solely as a scatter rejection device, substantial improvement in CT number accuracy can be achieved by increasing the grid ratio. Two-dimensional ASGs also provided significant CNR improvement even at lower grid ratios. Two-dimensional ASGs used in conjunction with the grid-based scatter sampling method provided further improvement in CT number accuracy, irrespective of the grid ratio, while preserving 2D ASGs' capacity to improve CNR. The combined effect of scatter rejection and residual scatter correction by 2D ASG may accelerate implementation of new techniques in CBCT that require high quantitative accuracy, such as radiotherapy dose calculation and dual energy CBCT.

Abstract PO009: Epigenetic silencing by SETDB1 represses tumor-cell intrinsic immunogenicity

Epigenetic alterations are defining features of many tumor types and have recently been implicated in tumor immunity. However, the epigenetic mechanisms that mediate immune sensitivity or resistance in cancer cells are poorly characterized. To systematically identify epigenetic regulators of immune evasion in cancer, we performed in vivo loss of function CRISPR screens against 936 chromatin regulator genes in syngeneic murine tumor models treated with immune checkpoint blockade. These screens identified SETDB1, an H3K9-methyltransferase, and associated members of the HUSH and KAP1 complexes as intrinsic mediators of immune evasion in cancer cells. We also found that amplification of SETDB1 (1q21) in certain human tumors is associated with immune exclusion and resistance to immune checkpoint blockade. Mechanistically, we find that SETDB1 targets broad domains, hundreds of kilobases in size, that are predominantly located within the open genome compartment “A” (i.e., euchromatin). These SETDB1 domains show strong enrichment for transposable elements (TEs) of the LTR family, and gene loci that arose through segmental duplication events, a key driver of mammalian genome evolution. Setdb1 KO derepresses latent regulatory elements at TEs within these regions and leads to the transcriptional up-regulation of nearby immune genes, including canonical stimulatory ligands of the NKG2D receptor. SETDB1 loss also triggers the activation of hundreds of TEs with the potential to encode retroviral proteins (Gag, Pol, Env), and promotes immune responses dependent on CD8+ T cells and tumor expression of MHC Class I. Our study establishes SETDB1 as an epigenetic checkpoint that represses intrinsic immunogenicity in cancer cells, and thus represents a novel target to enhance the efficacy and scope of immunotherapy.

Citation Format: Jingyi Wu, Arvin Iracheta-Vellve, James Patti, Jeffrey Hsu, Thomas Davis, Deborah Dele-Oni, Peter Du, Jeffrey Ishizuka, Sarah Kim, Susan Klaeger, Nelson Knudsen, Brian Miller, Tung Nguyen, Emily Robitschek, Emily Schneider, Margaret Zimmer, Jacob Jaffe, John Doench, W. Nicholas Haining, Kathleen Yates, Robert Manguso, Bradley Bernstein, Gabriel K. Griffin. Epigenetic silencing by SETDB1 represses tumor-cell intrinsic immunogenicity [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2020 Oct 19-20. Philadelphia (PA): AACR; Cancer Immunol Res 2021;9(2 Suppl):Abstract nr PO009.

A RAC-GEF network critical for early intestinal tumourigenesis

RAC1 activity is critical for intestinal homeostasis, and is required for hyperproliferation driven by loss of the tumour suppressor gene Apc in the murine intestine. To avoid the impact of direct targeting upon homeostasis, we reasoned that indirect targeting of RAC1 via RAC-GEFs might be effective. Transcriptional profiling of Apc deficient intestinal tissue identified Vav3 and Tiam1 as key targets. Deletion of these indicated that while TIAM1 deficiency could suppress Apc-driven hyperproliferation, it had no impact upon tumourigenesis, while VAV3 deficiency had no effect. Intriguingly, deletion of either gene resulted in upregulation of Vav2, with subsequent targeting of all three (Vav2-/- Vav3-/- Tiam1-/-), profoundly suppressing hyperproliferation, tumourigenesis and RAC1 activity, without impacting normal homeostasis. Critically, the observed RAC-GEF dependency was negated by oncogenic KRAS mutation. Together, these data demonstrate that while targeting RAC-GEF molecules may have therapeutic impact at early stages, this benefit may be lost in late stage disease.

Optimizing the Handling of Invasive Fungal Sinusitis Surgical Specimens

Introduction/Objective

Invasive fungal sinusitis (IFS) is an aggressive disease characterized by invasion of fungal hyphae into tissue/neurovascular bundles. This project assessed the handling of IFS specimens and implemented protocols to improve turnaround time (TAT).

Methods

A retrospective review of cases accessioned with a clinical concern for IFS from 2014-2019 was performed. TAT for each step in the specimen processing was recorded. A flowchart was created using stakeholder interviews and a revised protocol was developed after assessing critical needs. Assessment of interventions was performed following implementation of the new protocol. The protocol will be evaluated by prospective direct case-by-case feedback and after a 6-month interval (projected August/2020). At 6-months, goals are a 24 hours median time between frozen section and sign-out and elimination of outliers (greater than 2 working days).

Results

We identified 53 specimens from 32 patients in the pre-intervention period (36 cases positive for IFS). Median time from frozen section to final sign-out was 28 (5-312) hours. Four areas for improvements were identified:

(1) triaging specimens to different protocols according to arrival time, (2) optimized triaging for available histology processors, (3) standardized GMS ordering, and (4) standardized case delivery/communication with sign-out staff. Interventions include: protocol for processing specimens based on time of day, new histology protocols to expedite GMS performance, an email group for rapid communication with staff pathologists and histology, and a worksheet/checklist to track each case. After implementation of the protocol, 8 cases from 7 patients were received. Median time from frozen section to final sign-out was reduced to 20 (2 – 50) hours.

Conclusion

The protocol for handling IFS specimens became live on 2/1/2020. It has reduced TAT of suspected IFS cases, from a median of 28 hours to 20 hours. The longest interval to sign-out went from312 hours to 50 hours.

Affinity purification of human alpha galactosidase utilizing a novel small molecule biomimetic of alpha-D-galactose

Alpha galactosidase (a-Gal) is an acidic hydrolase that plays a critical role in hydrolyzing the terminal alpha-galactoyl moiety from glycolipids and glycoproteins. There are over a hundred mutations reported for the GLA gene that encodes a-Gal that result in reduced protein synthesis, protein instability, and reduction in function. The deficiencies of a-Gal can cause Fabry disease, a rare lysosomal storage disorder (LSD) caused by the failure to catabolize alpha-d-galactoyl glycolipid moieties. The current standard of care for Fabry disease is enzyme replacement therapy (ERT) where the purified recombinant form of human a-Gal is given to patients. The manufacture of a-Gal is currently performed utilizing traditional large-scale chromatography processes. Developing an affinity resin for the purification of a-Gal would reduce the complexity of the manufacturing process, reduce costs, and potentially produce a higher quality a-Gal. After the evaluation of many small molecules, a commercially available small molecule biomimetic, N-5-Carboxypentyl-1-deoxygalactonojirimycin (N5C-DGJ), was utilized for the development of a novel small molecule biomimetic affinity resin for a-Gal. Affinity purified a-Gal demonstrated a purity greater than 90%, exhibited expected thermal stability and specific activity. Complementing this affinity purification is the development of an elution buffer system that confers an increased thermal stability to a-Gal. The N5C-DGJ affinity resin tolerated sodium hydroxide sanitization with no loss of binding capacity, making it amenable to large scale purification processes and potential use in manufacturing. This novel method for purifying the challenging a-Gal enzyme can be extended to other enzyme replacement therapies.

Immediate weight bearing as tolerated (WBAT) correlates with a decreased length of stay post intramedullary fixation for subtrochanteric fractures: a multicenter retrospective cohort study

BACKGROUND

Subtrochanteric femur fractures associate with a relatively high complication rate and are traditionally treated operatively with a period of limited weight bearing. Transitioning from extramedullary to intramedullary implants, there are increasing biomechanical and clinical data to support early weight bearing. This multicenter retrospective study examines the effect of postoperative weight bearing as tolerated (WBAT) for subtrochanteric femur fractures. We hypothesize that WBAT will result in a decreased length of stay (LOS) without increasing the incidence of re-operation.

METHODS

This study assesses total LOS and postoperative LOS after intramedullary fixation for subtrochanteric fractures between postoperative weight bearing protocols across 6 level I trauma centers (n = 441). Analysis techniques consisted of multivariable linear regression and nonparametric comparative tests. Additional subanalyses were performed, targeting mechanism of injury (MOI), Winquist-Hansen fracture comminution, 20-year age strata, and injury severity score (ISS).

RESULTS

Total LOS was shorter in WBAT protocol within the overall sample (7.4 vs 9.7 days; p < 0.01). Rates of re-operation were similar between the two groups (10.6% vs 10.5%; p = 0.99). Stratified analysis identified patients between ages 41-80, WH comminution 2-3, high MOI, and ISS between 6-15 and 21-25 to demonstrate a significant reduction in LOS as a response to WBAT.

CONCLUSION

An immediate postoperative weight bearing as tolerated protocol in patients with subtrochanteric fractures reduced length of hospital stay with no significant difference in reoperation and complication rates. If no contraindication exists, immediate weight bearing as tolerated should be considered for patients with subtrochanteric femur fractures treated with statically locked intramedullary nails.

LEVEL OF EVIDENCE

Therapeutic Level III.

Regional and hemispheric susceptibility of the temporal lobe to FTLD-TDP type C pathology

Post-mortem studies show that focal anterior temporal lobe (ATL) neurodegeneration is most often caused by frontotemporal lobar degeneration TDP-43 type C pathology. Clinically, these patients are described with different terms, such as semantic variant primary progressive aphasia (svPPA), semantic dementia (SD), or right temporal variant frontotemporal dementia (FTD) depending on whether the predominant symptoms affect language, semantic knowledge for object or people, or socio-emotional behaviors. ATL atrophy presents with various degrees of lateralization, with right-sided cases considered rarer even though estimation of their prevalence is hampered by the paucity of studies on well-characterized, pathology-proven cohorts. Moreover, it is not clear whether left and right variants show a similar distribution of atrophy within the ATL cross-sectionally and longitudinally. Here we study the largest cohort to-date of pathology-proven TDP-43-C cases diagnosed during life as svPPA, SD or right temporal variant FTD. We analyzed clinical, cognitive, and neuroimaging data from 30 cases, a subset of which was followed longitudinally. Guided by recent structural and functional parcellation studies, we constructed four bilateral ATL regions of interest (ROIs). The computation of an atrophy lateralization index allowed the comparison of atrophy patterns between the two hemispheres. This led to an automatic, imaging-based classification of the cases as left-predominant or right-predominant. We then compared the two groups in terms of regional atrophy patterns within the ATL ROIs (cross-sectionally) and atrophy progression (longitudinally). Results showed that 40% of pathology proven cases of TDP-43-C diagnosed with a temporal variant presented with right-lateralized atrophy. Moreover, the findings of our ATL ROI analysis indicated that, irrespective of atrophy lateralization, atrophy distribution within both ATLs follows a medial-to-lateral gradient. Finally, in both left and right cases, atrophy appeared to progress to the contralateral ATL, and from the anterior temporal pole to posterior temporal and orbitofrontal regions. Taken together, our findings indicate that incipient right predominant ATL atrophy is common in TDP-43-C pathology, and that distribution of damage within the ATLs appears to be the same in left- and right- sided variants. Thus, regardless of differences in clinical phenotype and atrophy lateralization, both temporal variants of FTD should be viewed as a spectrum presentation of the same disease.

Exploring Sex Differences in the Effectiveness of Telehealth-Based Health Coaching in Weight Management in an Employee Population

PURPOSE

To explore a telehealth-based lifestyle therapeutics (THBC) program on weight loss (WL) and program satisfaction in an employer population.

DESIGN

This study was a collaboration between inHealth Lifestyle Therapeutics and a large national employer group including 685 participants (296 women [64% obese] and 389 men [62% obese]).

MEASURES

Percent WL and subjective rating (Perceived Program Value measured by a questionnaire) were assessed.

INTERVENTION

Average number of visits was 3.1 ± 0.4; each visit ranged between 20 and 45 minutes.

ANALYSIS

This study utilized a 2 × 2 block design using analysis of variance techniques based on sex (male and female) and initial body mass index (BMI) category (overweight and obese) tested at P ≤ .05.

RESULTS

There was no statistical difference in %WL between by sex (F_1,681 = 0.398, P = .528) nor an interaction between sex and BMI (F_1,681 = 0.809, P = .369). There was a statistically significant difference in %WL from pre to post program across initial BMI category (F_1,681 = 13.707, P ≤ .001) with obese participants losing an average of 1.1% (0.5%-1.6%) more than overweight participants (overweight 2.5% [2.1%-3.0%] vs obese 3.6% [3.2%-3.9%]). Obese participants were 1.15 (1.07-1.25) times more likely to lose weight compared to overweight participants. Analysis of variance power analysis indicated sufficient power on minimum factor combination n = 106 ( Effect Size = 0.282).

CONCLUSION

Results support the efficacy THBC in supporting WL with no reported differences between men and women, while having a high perceived value for employee participants.

Optimizing Coded Aperture Imaging techniques to allow for online tracking of fiducial markers with high-energy scattered radiation from treatment beam

PURPOSE

Real-time visualization of target motion using fiducial markers during radiation therapy treatment will allow for more accurate dose delivery. The purpose of this study was to optimize techniques for online fiducial marker tracking by detecting the scattered treatment beam through coded aperture imaging (CAI). Coded aperture imaging is a novel imaging technique that can allow target tracking in real time during treatment, and do so without adding any additional radiation dose, by making use of the scattered treatment beam radiation.

METHODS

Radiotherapy beams of various energies, incident on phantoms containing gold fiducial markers were modeled using MCNP6.2 Monte Carlo transport code. Orthogonal scatter radiographs were collected through a CAI geometry. After decoding the simulated radiograph data, the centroid location and FWHM/SNR of the fiducial signals were analyzed. The effects of properties related to the CA (rank, pattern, and physical dimensions), detector (dimensions and pixel count), position (CA and phantom), and the incident beam (spectrum and direction) were investigated. These variables were evaluated by quantifying the positional accuracy, resolution, and SNR of the fiducials' signal. The effects of phantom scatter and decoding artifacts were reduced via Fourier filtering to avoid treatment interruption and physical interaction with the coded mask.

RESULTS

The method was able to accurately localize the markers to within 1 pixel of a simulated radiograph. A 10 × 10 × 2 cm tungsten mask was chosen to attenuate >99 % of incident scatter through opaque elements, while minimizing collimation artifacts which arise from vignetting of the coded radiograph. Clear separation of centroids from fiducial signals with 2.5 mm separation was maintained, and initial optimization of parameters has produced an aperture which decodes the location of multiple fiducial markers inside a human phantom properly with a high SNR in the final radiograph image.

CONCLUSION

Current results show a proof of concept for a novel real-time imaging method. Coded aperture imaging is a promising technique for extracting the fiducial scatter signal from a broader Compton-scatter background. These results can be used to further optimize the CAI parameter space and guide fabrication and testing of a clinical device.