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.

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.

A novel pulsed field ablation system using linear and spiral ablation catheters can create large and durable endocardial and epicardial ventricular lesions in vivo

BACKGROUND

We investigated the preclinical safety and efficacy of ventricular pulsed field ablation (PFA) using a family of novel, 6-/8-Fr, linear, and spiral PFA/mapping catheters (CRC EP, Inc).

METHODS

QRS-gated, bipolar PFA (>2.0 kV) was performed in 10 healthy swine. Altogether, 20 endocardial and epicardial right and left ventricular applications were delivered. The catheters were inserted through an 8.5-Fr steerable introducer. The intensity of skeletal muscle activation was quantified using an accelerometer. Lesions were assessed by pre- versus post-PFA electrogram analysis, pacing threshold, 3D voltage mapping, necropsy, and histology. The swine rete mirabile, liver and kidneys were examined for embolic events.

RESULTS

All applications were single-shot (56 ± 18 s) without catheter repositioning. Minimal microbubbling was observed without significant skeletal muscle stimulation (mean acceleration 0.05 m/s2) or ventricular tachyarrhythmias. There was significant reduction in post- versus pre-PFA electrogram amplitude (0.5 ± 0.2 mV versus 3.2 ± 0.9 mV, P < 0.001) with a marked increase in pacing threshold (>20 mA versus 7.5 ± 2.9 mA, P < 0.001). All lesions were large and durable up to 28 days, measuring 32 ± 5 mm (length), 27 ± 8 mm (width), and 8 ± 3 mm (depth) using the spiral catheters and 43 ± 1 mm (length), 7 ± 1 mm (width), and 8 ± 1 mm (depth) using the linear catheters. Despite higher waveform voltages and prolonged applications, no thermal effects were detected at necropsy/histology. Moreover, gross and microscopic examinations revealed no evidence of thromboembolism, vascular or collateral injury.

CONCLUSIONS

A novel, QRS-gated PFA system using linear and spiral PFA catheters is capable of creating large and durable ventricular lesions in vivo without significant microbubbling, ventricular arrhythmias or thromboembolism.

Function and dysfunction of the dystonia network: an exploration of neural circuits that underlie the acquired and isolated dystonias

Dystonia is a highly prevalent movement disorder that can manifest at any time across the lifespan. An increasing number of investigations have tied this disorder to dysfunction of a broad "dystonia network" encompassing the cerebellum, thalamus, basal ganglia, and cortex. However, pinpointing how dysfunction of the various anatomic components of the network produces the wide variety of dystonia presentations across etiologies remains a difficult problem. In this review, a discussion of functional network findings in non-mendelian etiologies of dystonia is undertaken. Initially acquired etiologies of dystonia and how lesion location leads to alterations in network function are explored, first through an examination of cerebral palsy, in which early brain injury may lead to dystonic/dyskinetic forms of the movement disorder. The discussion of acquired etiologies then continues with an evaluation of the literature covering dystonia resulting from focal lesions followed by the isolated focal dystonias, both idiopathic and task dependent. Next, how the dystonia network responds to therapeutic interventions, from the "geste antagoniste" or "sensory trick" to botulinum toxin and deep brain stimulation, is covered with an eye towards finding similarities in network responses with effective treatment. Finally, an examination of how focal network disruptions in mouse models has informed our understanding of the circuits involved in dystonia is provided. Together, this article aims to offer a synthesis of the literature examining dystonia from the perspective of brain networks and it provides grounding for the perspective of dystonia as disorder of network function.

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.

Preclinical evaluation of a novel single-shot pulsed field ablation system for pulmonary vein and atrial ablation

INTRODUCTION

Pulsed field ablation (PFA) is a nonthermal ablative strategy that achieves cell death via electroporation. Herein, we investigated the preclinical safety and efficacy of PFA using two novel 8-French, 16-electrode spiral PFA/mapping catheters (ElePulse; CRC EP, Inc.).

METHODS

Bipolar PFA (>1.8 kV) was performed using 30 s, single-shot, QRS-gated applications. Altogether, 94 atrial structures were ablated in 23 swine, one canine, and one ovine, including right and left atria and atrial appendages, pulmonary veins, and superior and inferior (IVC) vena cavae. We also examined the impact of PFA on the phrenic nerve (14 swine) and on a deviated esophagus after delivery of PFA from inside the IVC (five swine).

RESULTS

All applications were single-shot without catheter repositioning. Minimal microbubbling was observed without significant skeletal muscle twitching/activation (mean acceleration: 0.05 m/s2 ). There was a marked reduction in post-PFA versus pre-PFA atrial electrogram amplitude (0.17 ± 0.21 vs. 1.18 ± 1.08 mV; p < .0001). Lesion durability was demonstrated up to 3 months in all targeted tissues. Histologically, lesions were contiguous and transmural, except in the atrial appendage, and without any thermal effects. Magnetic resonance, gross, and histologic examinations of the brain, rete mirabile, and kidneys revealed no thromboembolism. No acute/long-term phrenic nerve dysfunction was encountered. Although within 2 h of ablation, histologic examinations of the esophagus revealed acute PFA-related changes in the muscular layer, these completely resolved by 21 ± 5 days.

CONCLUSION

A novel, single-shot, spiral PFA system is capable of safely creating large, durable atrial lesions without significant adverse effects on the phrenic nerve or the esophagus.

Patient-Level Characteristics Associated with Tobacco Users and Nonusers at a Student-Run Free Clinic

OBJECTIVES

Many tobacco users are motivated to quit but lack the resources to do so. To date, studies characterizing tobacco users at student-run free clinics have used small sample sizes, which may not be large enough to detect differences across key variables. As such, we assessed sociodemographic differences between tobacco users and nonusers at a student-run free clinic using a pooled cross-sectional design.

METHODS

We used patient-level data from the electronic health records for all of the patients who were seen during January 2012 to February 2020 inclusive. Our dependent variable was whether patients self-reported tobacco use. We assessed for differences across age, sex, race/ethnicity, and education level using a multivariable logistic regression model.

RESULTS

Across 4264 patients, 28.7% reported tobacco use. When controlling for other factors, greater odds of tobacco use were observed in this cohort for patients who were male (odds ratio [OR] 1.690, 95% confidence interval [CI] 1.468-1.944), those with educational attainment of 9th to 11th grade (OR 2.291, 95% CI 1.558-3.369), and those who were high school graduates/completed the General Education Development test (OR 1.849, 95% CI 1.295-2.638) compared with those with less than a high school education. Similarly, patients of older age had greater odds of tobacco use.

CONCLUSIONS

Our study found patient-level differences that may need to be integrated into improving the reach of intervention methods. Future research should look at a broader set of metrics (eg, geographic location, socioeconomic status) and ascertain reasons for sociodemographic differences observed.

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.

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.

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.

Initial Specimen Diversion Device® Reduces Blood Culture Contamination and Vancomycin Use in Academic Medical Center

BACKGROUND

In suspected bloodstream infections, accurate blood culture results are critical to timely diagnoses and appropriate antibiotic administration.

AIM

An Initial Specimen Diversion Device®, Steripath®, (Magnolia Medical Technologies, Seattle, WA) was evaluated for efficacy in reducing blood culture contamination at Brooke Army Medical Center (6.8% six-month contamination rate prior to intervention) in a six-month quality improvement project.

METHODS

Blood cultures in the emergency department were collected using either Steripath® or the standard method. 20 mL of blood was cultured into an aerobic and anaerobic medium and incubated for five days using an automated microbial detection system immediately after collection. Positive bottles were Gram stained and plated. Rapid molecular PCR identification was performed on all first positive bottles within a blood culture set for each admission or ED visit. Speciation was deduced during antimicrobial sensitivity testing using the Vitek-2 instrument.

FINDINGS

Seven (7/1016, 0.69%) contamination events occurred when using Steripath® vs. 53 (53/800, 6.6%) contamination events when using the standard method. Steripath® use was associated with a 90% lower incidence of blood culture contamination vs. the standard method. Post-study, Steripath® use was implemented as standard practice hospital-wide, and a retrospective data analysis attributed a 31.4% decrease in vancomycin days of therapy to Steripath® adoption.

CONCLUSION

Using Steripath® significantly decreased blood culture contamination events for bacterial bloodstream infections compared to the standard method. Subsequent adoption of Steripath® reduced overall vancomycin usage. With widescale implementation Steripath® could bolster antibiotic stewardship, mitigating antibiotic resistance caused by unnecessary antibacterial treatments.

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.

LFA-1 and kindlin-3 enable the collaborative transport of SLP-76 microclusters by myosin and dynein motors

Integrin engagement within the immune synapse enhances T cell activation, but our understanding of this process is incomplete. In response to T cell receptor (TCR) ligation, SLP-76 (LCP2), ADAP (FYB1) and SKAP55 (SKAP1) are recruited into microclusters and activate integrins via the effectors talin-1 and kindlin-3 (FERMT3). We postulated that integrins influence the centripetal transport and signaling of SLP-76 microclusters via these linkages. We show that contractile myosin filaments surround and are co-transported with SLP-76 microclusters, and that TCR ligand density governs the centripetal movement of both structures. Centripetal transport requires formin activity, actomyosin contraction, microtubule integrity and dynein motor function. Although immobilized VLA-4 (α4β1 integrin) and LFA-1 (αLβ2 integrin) ligands arrest the centripetal movement of SLP-76 microclusters and myosin filaments, VLA-4 acts distally, while LFA-1 acts in the lamellum. Integrin β2, kindlin-3 and zyxin are required for complete centripetal transport, while integrin β1 and talin-1 are not. CD69 upregulation is similarly dependent on integrin β2, kindlin-3 and zyxin, but not talin-1. These findings highlight the integration of cytoskeletal systems within the immune synapse and reveal extracellular ligand-independent roles for LFA-1 and kindlin-3. This article has an associated First Person interview with the first author of the paper.

The Prop1-like homeobox gene unc-42 specifies the identity of synaptically connected neurons

Many neuronal identity regulators are expressed in distinct populations of cells in the nervous system, but their function is often analyzed only in specific isolated cellular contexts, thereby potentially leaving overarching themes in gene function undiscovered. We show here that the Caenorhabditis elegans Prop1-like homeobox gene unc-42 is expressed in 15 distinct sensory, inter- and motor neuron classes throughout the entire C. elegans nervous system. Strikingly, all 15 neuron classes expressing unc-42 are synaptically interconnected, prompting us to investigate whether unc-42 controls the functional properties of this circuit and perhaps also the assembly of these neurons into functional circuitry. We found that unc-42 defines the routes of communication between these interconnected neurons by controlling the expression of neurotransmitter pathway genes, neurotransmitter receptors, neuropeptides, and neuropeptide receptors. Anatomical analysis of unc-42 mutant animals reveals defects in axon pathfinding and synaptic connectivity, paralleled by expression defects of molecules involved in axon pathfinding, cell-cell recognition, and synaptic connectivity. We conclude that unc-42 establishes functional circuitry by acting as a terminal selector of functionally connected neuron types. We identify a number of additional transcription factors that are also expressed in synaptically connected neurons and propose that terminal selectors may also function as 'circuit organizer transcription factors' to control the assembly of functional circuitry throughout the nervous system. We hypothesize that such organizational properties of transcription factors may be reflective of not only ontogenetic, but perhaps also phylogenetic trajectories of neuronal circuit establishment.

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.

Evaluation of Blast Overpressure Exposure Effects on Concentration of Antibiotics in Mice

OBJECTIVE

Infection as sequelae to explosion-related injury is an enduring threat to our troops. There are limited data on the effects of blast on antibiotic pharmacokinetics (PK), pharmacodynamics (PD), and efficacy. The observational study presented here is our Institute's first attempt to address this issue by combining our existing interdepartmental blast, infection modeling, and in vivo PK/PD capabilities and was designed to determine the PK effects of blast on the first-line antibiotic, cefazolin, in an in vivo mouse model.

METHODS

A total of 160 male BALB/c mice were divided to sham and blast (exposed to blast overpressure of 19 psi) in two biological replicates. At 1 hour after blast/sham exposure, the animals received IV injection of cefazolin (328 mg/kg). Animals were euthanized at 3 minutes, 10 minutes, 15 minutes, 30 minutes, 1 hour, 3 hours, 6 hours, or 10 hours after the injection. Plasma and liver were analyzed for concentration of cefazolin using mass-spectrometry.

RESULTS

We observed increases in the concentration of cefazolin in the plasma and liver of blast exposed animals at later time points and increase in elimination half-life.

CONCLUSION

Our results indicate that blast-induced physiologic changes significantly influence cefazolin PK and suggest that efficacy could be affected in the context of the blast; assessment of efficacy and PD effects require further investigation. Metabolic changes resulting from blast may influence other classes of antibiotics and other therapeutics used with these injuries. Therefore, this may have important treatment considerations in other areas of military medicine.

Saccharomyces boulardii CNCM I-745 probiotic does not alter the pharmacokinetics of amoxicillin

Background Probiotics are live microbial organisms that provide benefit to the host while co-habitating in the gastrointestinal tract. Probiotics are safe, available over the counter, and have clinical benefit by reducing the number of antibiotic-associated diarrhea days. Prescriptions from providers and direct consumer demand of probiotics appear to be on the rise. Several recent animal studies have demonstrated that probiotics may have significant effect on absorption of co-administered drugs. However, to date, most probiotic-drug interaction studies in animal models have been limited to bacterial probiotics and nonantibiotic drugs. Methods We performed a traditional pharmacokinetic mouse study examining the interactions between a common commercially available yeast probiotic, Saccharomyces boulardii CNCM I-745 (Florastor®) and an orally administered amoxicillin. Results We showed that there were no significant differences in pharmacokinetic parameters (half-life, area under the curve, peak concentrations, time to reach maximum concentration, elimination rate constant) of amoxicillin between the probiotic treated and untreated control groups. Conclusions Altogether, our findings suggest that coadministration or concurrent use of S. boulardii probiotic and amoxicillin would not likely alter the efficacy of amoxicillin therapy.

Ciliary Rab28 and the BBSome negatively regulate extracellular vesicle shedding

Cilia both receive and send information, the latter in the form of extracellular vesicles (EVs). EVs are nano-communication devices that influence cell, tissue, and organism behavior. Mechanisms driving ciliary EV biogenesis are almost entirely unknown. Here, we show that the ciliary G-protein Rab28, associated with human autosomal recessive cone-rod dystrophy, negatively regulates EV levels in the sensory organs of Caenorhabditis elegans in a cilia specific manner. Sequential targeting of lipidated Rab28 to periciliary and ciliary membranes is highly dependent on the BBSome and the prenyl-binding protein phosphodiesterase 6 subunit delta (PDE6D), respectively, and BBSome loss causes excessive and ectopic EV production. We also find that EV defective mutants display abnormalities in sensory compartment morphogenesis. Together, these findings reveal that Rab28 and the BBSome are key in vivo regulators of EV production at the periciliary membrane and suggest that EVs may mediate signaling between cilia and glia to shape sensory organ compartments. Our data also suggest that defects in the biogenesis of cilia-related EVs may contribute to human ciliopathies.