A Machine Learning Algorithm Improves the Diagnostic Accuracy of the Histologic Component of Antibody Mediated Rejection (AMR-H) in Cardiac Transplant Endomyocardial Biopsies.

BACKGROUND: Pathologic antibody mediated rejection (pAMR) remains a major driver of graft failure in cardiac transplant patients. The endomyocardial biopsy remains the primary diagnostic tool but presents with challenges, particularly in distinguishing the histologic component (pAMR-H) defined by 1) intravascular macrophage accumulation in capillaries and 2) activated endothelial cells that expand the cytoplasm to narrow or occlude the vascular lumen. Frequently, pAMR-H is difficult to distinguish from acute cellular rejection (ACR) and healing injury. With the advent of digital slide scanning and advances in machine deep learning, artificial intelligence technology is widely under investigation in the areas of oncologic pathology, but in its infancy in transplant pathology. For the first time, we determined if a machine learning algorithm could distinguish pAMR-H from normal myocardium, healing injury and ACR. MATERIALS AND METHODS: A total of 4,212 annotations (1,053 regions of normal, 1,053 pAMR-H, 1,053 healing injury and 1,053 ACR) were completed from 300 hematoxylin and eosin slides scanned using a Leica Aperio GT450 digital whole slide scanner at 40X magnification. All regions of pAMR-H were annotated from patients confirmed with a previous diagnosis of pAMR2 (>50% positive C4d immunofluorescence and/or >10% CD68 positive intravascular macrophages). Annotations were imported into a Python 3.7 development environment using the OpenSlide™ package and a convolutional neural network approach utilizing transfer learning was performed. RESULTS: The machine learning algorithm showed 98% overall validation accuracy and pAMR-H was correctly distinguished from specific categories with the following accuracies: normal myocardium (99.2%), healing injury (99.5%) and ACR (99.5%). CONCLUSION: Our novel deep learning algorithm can reach acceptable, and possibly surpass, performance of current diagnostic standards of identifying pAMR-H. Such a tool may serve as an adjunct diagnostic aid for improving the pathologist's accuracy and reproducibility, especially in difficult cases with high inter-observer variability. This is one of the first studies that provides evidence that an artificial intelligence machine learning algorithm can be trained and validated to diagnose pAMR-H in cardiac transplant patients. Ongoing studies include multi-institutional verification testing to ensure generalizability.

Adaptation and study protocol for harvest for health together Arizona: A mentored community garden intervention for survivors of cancer.

Background: Current health behavior recommendations for skin cancer prevention, treatment, and survivorship are the same for survivors of other cancers; they include eating a healthy diet, being physically active, maintaining a healthy weight, and minimizing ultraviolet (U.V.) exposure. Few interventions exist to support health behaviors beyond U.V. exposure. We adapted Harvest for Health, a home-based mentored gardening intervention for cancer survivors, for implementation in Arizona as a community-based intervention. Methods: Stakeholder-informed adaptations for Harvest for Health Together Arizona (H4H2-AZ) included updating intervention materials to be relevant to the arid desert environment, emphasizing the importance of sun safety in cancer survivorship, and shifting from a home-based to a community-based delivery model. Participants will be enrolled in cohorts aligned with growing seasons (e.g., spring, monsoon, fall) and matched to an individual 30 ft2 community garden plot for two growing seasons (6 months). Original intervention components retained are: 1) Master Gardeners deliver the intervention providing one-to-one mentorship and 2) gardening materials and supplies provided. This pilot six-month single-arm intervention will determine feasibility, acceptability, and appropriateness of an evidence-based adapted mentored community gardening intervention for survivors of skin cancer as primary outcomes. Secondary outcomes are to explore the effects on cancer preventive health behaviors and health-related quality of life. Discussion: This pilot single-arm intervention will determine feasibility, acceptability, and appropriateness of an evidence-based adapted mentored community gardening intervention for survivors of skin cancer. If successful, the intervention could be widely implemented throughout existing Master Gardener programs and community garden networks for survivors of other cancers. Trial registration: ClinicalTrials.gov identifier: NCT05648604. Trial registered on December 13, 2022.

3D models of the cardiac conduction system in healthy neonatal human hearts.

Iatrogenic damage to the cardiac conduction system (CCS) remains a significant risk during congenital heart surgery. Current surgical best practice involves using superficial anatomical landmarks to locate and avoid damaging the CCS. Prior work indicates inherent variability in the anatomy of the CCS and supporting tissues. This study introduces high-resolution, 3D models of the CCS in normal pediatric human hearts to evaluate variability in the nodes and surrounding structures. Human pediatric hearts were obtained with an average donor age of 2.7 days. A pipeline was developed to excise, section, stain, and image atrioventricular (AVN) and sinus nodal (SN) tissue regions. A convolutional neural network was trained to enable precise multi-class segmentation of whole-slide images, which were subsequently used to generate high- resolution 3D tissue models. Nodal tissue region models were created. All models (10 AVN, 8 SN) contain tissue composition of neural tissue, vasculature, and nodal tissues at micrometer resolution. We describe novel nodal anatomical variations. We found that the depth of the His bundle in females was on average 304 µm shallower than those of male patients. These models provide surgeons with insight into the heterogeneity of the nodal regions and the intricate relationships between the CCS and surrounding structures.

Report of the 2022 Banff Heart Concurrent: Focus on non-human leukocyte antigen antibodies in rejection and the pathology of "mixed" rejection.

The Banff Heart Concurrent Session, held as part of the 16th Banff Foundation for Allograft Pathology Conference at Banff, Alberta, Canada, on September 21, 2022, focused on 2 major topics: non-human leukocyte antigen (HLA) antibodies and mixed rejection. Each topic was addressed in a multidisciplinary fashion with clinical, immunological, and pathology perspectives and future developments and prospectives. Following the Banff organization model and principles, the collective aim of the speakers on each topic was to • Determine current knowledge gaps in heart transplant pathology • Identify limitations of current pathology classification systems • Discuss next steps in addressing gaps and refining classification system.

Improving autism identification and support for individuals assigned female at birth: clinical suggestions and research priorities.

Emerging evidence suggests that the higher prevalence of autism in individuals who are assigned male than assigned female at birth results from both biological factors and identification biases. Autistic individuals who are assigned female at birth (AFAB) and those who are gender diverse experience health disparities and clinical inequity, including late or missed diagnosis and inadequate support. In this Viewpoint, an international panel of clinicians, scientists, and community members with lived experiences of autism reviewed the challenges in identifying autism in individuals who are AFAB and proposed clinical and research directions to promote the health, development, and wellbeing of autistic AFAB individuals. The recognition challenges stem from the interplay between cognitive differences and nuanced or different presentations of autism in some AFAB individuals; expectancy, gender-related, and autism-related biases held by clinicians; and social determinants. We recommend that professional development for clinicians be supported by health-care systems, professional societies, and governing bodies to improve equitable access to assessment and earlier identification of autism in AFAB individuals. Autistic AFAB individuals should receive tailored support in education, identity development, health care, and social and professional sense of belonging.

Consensus statement on the processing, interpretation and reporting of temporal artery biopsy for arteritis.

Giant cell arteritis (GCA) is the most common systemic vasculitis in adults in Europe and North America, typically involving the extra-cranial branches of the carotid arteries and the thoracic aorta. Despite advances in noninvasive imaging, temporal artery biopsy (TAB) remains the gold standard for establishing a GCA diagnosis. The processing of TAB depends largely on individual institutional protocol, and the interpretation and reporting practices vary among pathologists. To address this lack of uniformity, the Society for Cardiovascular Pathology formed a committee tasked with establishing consensus guidelines for the processing, interpretation, and reporting of TAB specimens, based on the existing literature. This consensus statement includes a discussion of the differential diagnoses including other forms of arteritis and noninflammatory changes of the temporal artery.

Manduca sexta caterpillars parasitized by the wasp Cotesia congregata stop chewing despite an intact motor system.

The parasitic wasp Cotesia congregata suppresses feeding in its host, the caterpillar Manduca sexta, during specific periods of wasp development. We examined both feeding behaviour and the neurophysiology of the mandibular closer muscle in parasitized and unparasitized control M. sexta to determine how the wasp may accomplish this. To test whether the wasps activated a pre-existing host mechanism for feeding cessation, we examined the microstructure of feeding behaviour in caterpillars that stopped feeding due to illness-induced anorexia or an impending moult. These microstructures were compared with that shown by parasitized caterpillars. While there were overall differences between parasitized and unparasitized caterpillars, the groups showed similar progression in feeding microstructure as feeding ended, suggesting a common pattern for terminating a meal. Parasitized caterpillars also consumed less leaf area in 100 bites than control caterpillars at around the same time their feeding microstructure changed. The decline in food consumption was accompanied by fewer spikes per burst and shorter burst durations in chewing muscle electromyograms. Similar extracellular results were obtained from the motorneuron of the mandibular closer muscle. However, chewing was dramatically re-activated in non-feeding parasitized caterpillars if the connectives posterior to the suboesophageal ganglion were severed. The same result was observed in unparasitized caterpillars given the same treatment. Our results suggest that the reduced feeding in parasitized caterpillars is not due to damage to the central pattern generator (CPG) for chewing, motor nerves or chewing muscles, but is more likely to be due to a suppression of chewing CPG activity by ascending or descending inputs.

Muscle in the caterpillar Manduca sexta responds to an immune challenge, but at a cost, suggesting a physiological trade-off.

Although skeletal muscle is a specialized tissue that provides the motor for movement, it also participates in other functions, including the immune response. However, little is known about the effects of this multitasking on muscle. We show that muscle loses some of its capacity while it is participating in the immune response. Caterpillars (Manduca sexta) were exposed to an immune challenge, predator stress or a combination of immune challenge and predator stress. The expression of immune genes (toll-1, domeless, cactus, tube and attacin) increased in body wall muscle after exposure to an immune challenge. Muscle also showed a reduction in the amount of the energy storage molecule glycogen. During an immune challenge, the force of the defensive strike, an important anti-predator behaviour in M. sexta, was reduced. Caterpillars were also less able to defend themselves against a common enemy, the wasp Cotesia congregata, suggesting that the effect on muscle is biologically significant. Our results support the concept of an integrated defence system in which life-threatening events activate organism-wide responses. We suggest that increased mortality from predation is a non-immunological cost of infection in M. sexta. Our study also suggests that one reason non-immunological costs of infection exist is because of the participation of diverse organs, such as muscle, in immunity.

Association of Sun Safety Behaviors and Barriers with Sunburn History in College Students in a Region with High UV Exposure.

Over five million cases of skin cancer are diagnosed each year in the United States with melanoma the third most common cancer in young adults. While publications have shown that sunburns increase the risk of developing melanoma throughout the lifetime including in adolescence and adulthood showing the importance of altering sun exposing behaviors throughout the lifetime, use of sun protection in college students remails low. In Fall 2019, an online survey of undergraduate students living on campus at a large southwestern university was conducted to determine the frequency of recent sunburns as well as sun protective behaviors and perceived knowledge of and barriers to sun protection. Associations between knowledge, behaviors, and barriers with self-reported sunburn were evaluated using logistic regression. Over 46% of 458 students reported at least one sunburn in the past three months and 21% reported having multiple sunburns in that period. Furthermore, 53% reported that they intentionally tanned their skin outdoors occasionally or more frequently, while 6.4% reported using an indoor tanning bed occasionally or more. Adjusted for skin sensitivity, recent sunburn history was associated with higher tanning activity scores and with high agreement that tanning was attractive (p < 0.01). This information can inform a more targeted series of intervention programming on the university campus.

Health Risk Implications of Volatile Organic Compounds in Wildfire Smoke During the 2019 FIREX-AQ Campaign and Beyond.

Fire Influence on Regional to Global Environments and Air Quality was a NOAA/NASA collaborative campaign conducted during the summer of 2019. The objectives included identifying and quantifying wildfire composition, smoke evolution, and climate and health impacts of wildfires and agricultural fires in the United States. Ground based mobile sampling via sorbent tubes occurred at the Nethker and Williams Flats fires (2019) and Chief Timothy and Whitetail Loop fires (2020) in Idaho and Washington. Air samples were analyzed through thermal desorption-gas chromatography-mass spectrometry for a variety of volatile organic compounds to elucidate both composition and health impacts. Benzene, toluene, ethylbenzene, xylenes, butenes, phenol, isoprene and pinenes were observed in the wildfire smoke, with benzene ranging from 0.04 to 25 ppbv. Health risk was assessed for each fire by determining sub-chronic (wildfire event) and projected chronic inhalation risk exposure from benzene, a carcinogen, as well as other non-carcinogenic compounds including toluene, ethylbenzene, xylenes, and hexane. The cancer risk of benzene from sub-chronic exposure was 1 extra cancer per million people and ranged from 1 to 19 extra cancers per million people for the projected chronic scenarios, compared to a background level of 1 extra cancer per million people. The hazard index of non-carcinogenic compounds was less than one for all scenarios and wildfires sampled, which was considered low risk for non-cancer health events.

Behavioral and neural mechanisms of latent inhibition.

Fear is an adaptive emotion that serves to protect an organism against potential dangers. It is often studied using classical conditioning paradigms where a conditioned stimulus is paired with an aversive unconditioned stimulus to induce a threat response. Less commonly studied is a phenomenon that is related to this form of conditioning, known as latent inhibition. Latent inhibition (LI) is a paradigm in which a neutral cue is repeatedly presented in the absence of any aversive associations. Subsequent pairing of this pre-exposed cue with an aversive stimulus typically leads to reduced expression of a conditioned fear/threat response. In this article, we review some of the theoretical basis for LI and its behavioral and neural mechanisms. We compare and contrast LI and fear/threat extinction-a process in which a previously conditioned cue is repeatedly presented in the absence of aversive outcomes. We end with highlighting the potential clinical utility of LI. Particularly, we focus on how LI application could be useful for enhancing resilience, especially for individuals who are more prone to continuous exposure to trauma and stressful environments, such as healthcare workers and first responders. The knowledge to be gained from advancing our understanding of neural mechanisms in latent inhibition could be applicable across psychiatric disorders characterized by exaggerated fear responses and impaired emotion regulation.

Diffusive uptake rates for passive air sampling: Application to volatile organic compound exposure during FIREX-AQ campaign.

Passive (diffusive) sampling using sorbents is an economical and versatile method of measuring pollutants in air, including volatile organic compounds (VOCs). Diffusive uptake rates (UTRs) are needed for each analyte to obtain average concentrations during a specific passive sampling time duration. Here, a simultaneous active/diffusive ambient air sampling technique on Tenax®TA was employed to measure 24-hours, 7, 14 and 28-days UTRs of up to 27 VOCs, including benzene, toluene, ethylbenzene, xylenes (BTEX), C6-C12 hydrocarbons, benzenes derivatives, tetrachloroethylene, pinenes and limonene. Samples were analyzed via thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) for desired analytes. Seven-day UTR values ranged from 0.17 to 0.59 mL/min and many compounds exhibited a linear relationship with UTR and time duration up to 14 or 28 days. This may be the most comprehensive UTR tabulation of VOCs on Tenax®TA for time periods of 24 hours -28 days available. These rates were applied to VOC data measured during the 2019 NASA/NOAA Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign, with goals to determine the chemical composition of western US wildfire smoke and to assess human exposure to air toxics. Summer 2019 exposure levels of BTEX at five Northwestern cities were low and the cancer risk due to benzene was assessed during FIREX-AQ to be background or 1 × 10-6. The UTRs derived here can be useful in applications of diffusive sampling, including estimation of sub-chronic to chronic human exposure risk of air toxics and wildfire smoke.

Steroid sulfatase in the mouse NIH-3T3 fibroblast cell line: Characterization, and downregulation by glucocorticoids.

Steroid hormones often circulate in the blood as inactive sulfated forms, such as estrone sulfate and dehydroepiandrosterone sulfate. The enzyme steroid sulfatase (STS) converts these steroids into active forms, mainly estrogens, in peripheral tissues. We have previously characterized STS activity in human and mouse breast and bone tissues, and we have shown that STS can provide estrogens to these tissues from circulating sulfated precursors. This study was designed to characterize STS activity in a mouse fibroblast cell line (NIH-3T3). Using a radioactive estrone sulfate (E1S) conversion assay, we detected STS activity in cultured NIH-3T3 cells. This activity was blocked by the STS inhibitors EMATE and STX-64, indicating authentic STS activity. We also found that microsomes prepared from NIH-3T3 cells had relatively high STS activity and that cytosols had low activity, consistent with the known distribution of this enzyme to the endoplasmic reticulum. Michaelis-Menten analysis of the NIH-3T3 microsomes indicated a Km of 10.9 µM using E1S as substrate. Primary fibroblasts prepared from mouse ears and tails also had measurable STS activity, as indicated by 3H-E1S conversion assay, further supporting the conclusion that fibroblasts possess STS. Furthermore, Western blotting confirmed the presence of immunoreactive STS in NIH-3T3 microsomes. With regard to regulation, treatments of cultured NIH-3T3 cells revealed that cortisol and the synthetic glucocorticoids dexamethasone and prednisolone decreased STS activity, as we have found for cell lines from other tissues. The effect of cortisol was seen at both 10 µM and 1.0 µM but not at 0.1 µM. Western blotting also indicated a decrease in STS immunoreactivity in cortisol-treated microsomes. The reduction in STS activity by dexamethasone in whole cells was reversed by the glucocorticoid receptor antagonist RU-486, indicating that glucocorticoid downregulation of STS activity is receptor mediated. An inhibition assay on NIH-3T3 microsomes revealed that STS activity was inhibited significantly by 10 µM estradiol-17ß, a known substrate inhibitor of E1S for STS, but not by 10 µM cortisol. This is consistent with the idea that cortisol inhibits STS in NIH-3T3 cells through a regulatory mechanism rather than by substrate inhibition. Our results could have important implications regarding local estrogen production by STS in fibroblasts, which are the most common connective tissue cells in the body, and on possible regulation of local estrogen levels by cortisol.

Does increasing the number of channels during neuromuscular electrical stimulation reduce fatigability and produce larger contractions with less discomfort?

PURPOSE: Neuromuscular electrical stimulation (NMES) is often delivered at frequencies that recruit motor units (MUs) at unphysiologically high rates, leading to contraction fatigability. Rotating NMES pulses between multiple electrodes recruits subpopulations of MUs from each site, reducing MU firing rates and fatigability. This study was designed to determine whether rotating pulses between an increasing number of stimulation channels (cathodes) reduces contraction fatigability and increases the ability to generate torque during NMES. A secondary outcome was perceived discomfort. METHODS: Fifteen neurologically intact volunteers completed four sessions. NMES was delivered over the quadriceps through 1 (NMES1), 2 (NMES2), 4 (NMES4) or 8 (NMES8) channels. Fatigability was assessed over 100 contractions (1-s on/1-s off) at an initial contraction amplitude that was 20% of a maximal voluntary contraction. Torque-frequency relationships were characterized over six frequencies from 20 to 120 Hz. RESULTS: NMES4 and NMES8 resulted in less decline in peak torque (42 and 41%) over the 100 contractions than NMES1 and NMES2 (53 and 50% decline). Increasing frequency from 20 to 120 Hz increased torque by 7, 13, 21 and 24% MVC, for NMES1, NMES2, NMES4 and NMES8, respectively. Perceived discomfort was highest during NMES8. CONCLUSION: NMES4 and NMES8 reduced contraction fatigability and generated larger contractions across a range of frequencies than NMES1 and NMES2. NMES8 produced the most discomfort, likely due to small electrodes and high current density. During NMES, more is not better and rotating pulses between four channels may be optimal to reduce contraction fatigability and produce larger contractions with minimal discomfort compared to conventional NMES configurations.

Indirect Vibration of the Upper Limbs Alters Transmission Along Spinal but Not Corticospinal Pathways.

The use of upper limb vibration (ULV) during exercise and rehabilitation continues to gain popularity as a modality to improve function and performance. Currently, a lack of knowledge of the pathways being altered during ULV limits its effective implementation. Therefore, the aim of this study was to investigate whether indirect ULV modulates transmission along spinal and corticospinal pathways that control the human forearm. All measures were assessed under CONTROL (no vibration) and ULV (30 Hz; 0.4 mm displacement) conditions while participants maintained a small contraction of the right flexor carpi radialis (FCR) muscle. To assess spinal pathways, Hoffmann reflexes (H-reflexes) elicited by stimulation of the median nerve were recorded from FCR with motor response (M-wave) amplitudes matched between conditions. An H-reflex conditioning paradigm was also used to assess changes in presynaptic inhibition by stimulating the superficial radial (SR) nerve (5 pulses at 300Hz) 37 ms prior to median nerve stimulation. Cutaneous reflexes in FCR elicited by stimulation of the SR nerve at the wrist were also recorded. To assess corticospinal pathways, motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation of the contralateral motor cortex were recorded from the right FCR and biceps brachii (BB). ULV significantly reduced H-reflex amplitude by 15.7% for both conditioned and unconditioned reflexes (24.0 ± 15.7 vs. 18.4 ± 11.2% M max ; p < 0.05). Middle latency cutaneous reflexes were also significantly reduced by 20.0% from CONTROL (-1.50 ± 2.1% Mmax) to ULV (-1.73 ± 2.2% Mmax; p < 0.05). There was no significant effect of ULV on MEP amplitude (p > 0.05). Therefore, ULV inhibits cutaneous and H-reflex transmission without influencing corticospinal excitability of the forearm flexors suggesting increased presynaptic inhibition of afferent transmission as a likely mechanism. A general increase in inhibition of spinal pathways with ULV may have important implications for improving rehabilitation for individuals with spasticity (SCI, stroke, MS, etc.).