Procedural Interventions for Terminally Ill Children - Are We Aiding Palliation?

Objectives: Many children undergo surgery or an invasive procedure during their terminal hospital admission.1 The types of procedures, patients, and the intent of the procedures has not been well defined. Understanding these details may help pediatric surgeons better determine the clinical settings in which certain procedures will not enhance palliation or survival. Methods: A retrospective single institution chart review was performed for patients age 14 days to 18 years with chronic conditions who died while inpatient from 2013-2017. Data was gathered on demographics, primary diagnosis, intubation status, palliative care involvement, duration of hospital stay, length of palliative care involvement, and total number of procedures. Negative binomial regression was used to assess association with number of procedures. Results: 132 children met inclusion criteria. Most children were White and less than one year old. The most common type of diagnosis was cardiac in nature. Children underwent an average of three procedures. 75% were intubated and 77.5% had palliative care involved. Patients who were less than one year old at death were more likely to have been intubated, had longer terminal hospital stays, and had more procedures. Those who were intubated underwent more procedures and had longer hospital stays. Those with longer palliative care involvement had fewer procedures. Conclusions: Children undergo a significant number of surgical procedures during their terminal hospitalization. This may be influenced by age, intubation status, and length of stay. Ongoing study may help refine which procedures may have limited impact on survival in the chronically ill pediatric population.

Bundling Colorectal Cancer Screening Outreach with Screening for Social Risk in Federally Qualified Health Centers: A Stepped-Wedge Implementation-Effectiveness Study

BACKGROUND

Bundling is combining individual interventions to meet quality metrics. Bundling offers of cancer screening with screening for social determinants of health (SDOH) may enable health centers to assist patients with social risks and yield efficiencies.

OBJECTIVE

To measure effects of bundling fecal immunochemical testing (FIT) and SDOH screening in federally qualified health centers (FQHCs).

DESIGN

Clustered stepped-wedge trial.

PARTICIPANTS

Four Massachusetts FQHCs randomized to implement bundled FIT-SDOH over 8-week "steps."

INTERVENTION

Outreach to 50-75-year-olds overdue for CRC screening to offer FIT with SDOH screening. The implementation strategy used facilitation and training for data monitoring and reporting.

MAIN MEASURES

Implementation process descriptions, data from facilitation meetings, and CRC and SDOH screening rates. Rates were compared between implementation and control FQHCs in each "step" by fitting generalized linear mixed-effects models with random intercepts for FQHCs, patients, and "step" by FQHC.

KEY RESULTS

FQHCs tailored implementation processes to their infrastructure, workflows, and staffing and prioritized different groups for outreach. Two FQHCs used population health outreach, and two integrated FIT-SDOH within established programs, such as pre-visit planning. Of 34,588 patients overdue for CRC screening, 54% were female; 20% Black, 11% Latino, 10% Asian, and 47% white; 32% had Medicaid, 16% Medicare, 32% private insurance, and 11% uninsured. Odds of CRC screening completion in implementation "steps" compared to controls were higher overall and among groups prioritized for outreach (overall: adjusted odds ratio (aOR) 2.41, p = 0.005; prioritized: aOR 2.88, p = 0.002). Odds of SDOH screening did not differ across "steps."

CONCLUSIONS

As healthcare systems are required to conduct more screenings, it is notable that outreach for a long-standing cancer screening requirement increased screening, even when bundled with a newer screening requirement. This outreach was feasible in a real-world safety-net clinical population and may conserve resources, especially compared to more complex or intensive outreach strategies.

CLINICAL TRIALS REGISTRATION

NCT04585919.

The First Statewide Implementation of a Regional Disaster Teleconsultation System to Expand Critical Care Surge Capacity: A Case Study in Vermont

Background: In December 2021, the Region 1 Disaster Health Response System, the state of Vermont, and the National Emergency Tele-Critical Care Network partnered to provide statewide access to disaster teleconsultations during COVID-19 surge conditions. In this case report, we describe how a disaster teleconsultation system was implemented in Vermont to provide access to temporary tele-critical care consultations during the Omicron COVID-19 surge. Methods: We measured the time from request of service to implementation and calculated descriptive statistics. Results: Seven of Vermont's 14 hospitals requested the service. Despite a technology solution capable of providing services within hours, mean time to service implementation was 27 days (interquartile range 20-41 days). Conclusions: Integration of disaster teleconsultation systems into state and local emergency management plans are needed to bring administrative start-up times in line with technical readiness.

Receptors underlying an odorant's valence across concentrations in Drosophila larvae

Odorants interact with receptors expressed in specialized olfactory neurons, and neurons of the same class send their axons to distinct glomeruli in the brain. The stereotypic spatial glomerular activity map generates recognition and the behavioral response for the odorant. The valence of an odorant changes with concentration, typically becoming aversive at higher concentrations. Interestingly, in Drosophila larvae, the odorant (E)-2-hexenal is aversive at low concentrations and attractive at higher concentrations. We investigated the molecular and neural basis of this phenomenon, focusing on how activities of different olfactory neurons conveying opposing effects dictate behaviors. We identified the repellant neuron in the larvae as one expressing the olfactory receptor Or7a, whose activation alone at low concentrations of (E)-2-hexenal elicits an avoidance response in an Or7a-dependent manner. We demonstrate that avoidance can be overcome at higher concentrations by activation of additional neurons that are known to be attractive, most notably odorants that are known activators of Or42a and Or85c. These findings suggest that in the larval stage, the attraction-conveying neurons can overcome the aversion-conveying channels for (E)-2-hexenal.

Impact of a Reading Room Coordinator on Efficiency of On-Call Radiology Residents

OBJECTIVES

Few level I trauma, tertiary care, academic centers have a paid, permanent reading room coordinator (RRC) to facilitate image management services during off-hour calls, to minimize interruptions to reading workflow. The purpose of this study is to investigate the effect of an RRC on the efficiency of radiology residents signing preliminary reports for emergency department (ED) and inpatient studies.

METHODS

A pre- and postintervention retrospective review was performed, using carestream PACS to retrieve imaging studies read on call during two time periods-July 1 to December 1, 2019 (pre-RRC), and July 1 to December 1, 2021 (post-RRC). Efficiency of residents signing preliminary reports was measured by turnaround time (TAT), defined as the time from when a study was marked complete by a technologist to when a preliminary report was signed by a resident, in PACS.

RESULTS

In the above time periods, residents interpreted a total of 64,406 studies on call. For ED studies, the mean TAT was 7.0 min shorter post-RRC, compared with pre-RRC (95% confidence interval [CI]: -7.8 to -6.1, (t = 15.50, degrees of freedom (df) = 31,866, P < .0001). The percentage of ED studies signed within 30 min increased from 57.7% to 65.8%, an increase of 8.1% (95% CI: 7.0% to 9.1%) after employing an RRC (χ2 = 228.11, df = 1, P < .0001). For inpatient studies, the mean TAT was 10.2 min shorter post-RRC (95% CI: -12.3 to -8.0, t = 9.22, df = 25,193, P < .0001).

CONCLUSIONS

An RRC increased radiology resident on-call workflow efficiency, facilitating care for patients in both the ED and inpatient setting.

Evaluating top-down, bottom-up, and environmental drivers of pelagic food web dynamics along an estuarine gradient

Identification of the key biotic and abiotic drivers within food webs is important for understanding species abundance changes in ecosystems, particularly across ecotones where there may be strong variation in interaction strengths. Using structural equation models (SEMs) and four decades of integrated data from the San Francisco Estuary, we investigated the relative effects of top-down, bottom-up, and environmental drivers on multiple trophic levels of the pelagic food web along an estuarine salinity gradient and at both annual and monthly temporal resolutions. We found that interactions varied across the estuarine gradient and that the detectability of different interactions depended on timescale. For example, for zooplankton and estuarine fishes, bottom-up effects appeared to be stronger in the freshwater upstream regions, while top-down effects were stronger in the brackish downstream regions. Some relationships (e.g., bottom-up effects of phytoplankton on zooplankton) were seen primarily at annual timescales, whereas others (e.g., temperature effects) were only observed at monthly timescales. We also found that the net effect of environmental drivers was similar to or greater than bottom-up and top-down effects for all food web components. These findings can help identify which trophic levels or environmental factors could be targeted by management actions to have the greatest impact on estuarine forage fishes and the spatial and temporal scale at which responses might be observed. More broadly, this study highlights how environmental gradients can structure community interactions and how long-term data sets can be leveraged to generate insights across multiple scales.

Plasticity of gene expression in the nervous system by exposure to environmental odorants that inhibit HDACs

Eukaryotes respond to secreted metabolites from the microbiome. However, little is known about the effects of exposure to volatiles emitted by microbes or in the environment that we are exposed to over longer durations. Using Drosophila melanogaster, we evaluated a yeast-emitted volatile, diacetyl, found at high levels around fermenting fruits where they spend long periods of time. Exposure to the diacetyl molecules in headspace alters gene expression in the antenna. In vitro experiments demonstrated that diacetyl and structurally related volatiles inhibited conserved histone deacetylases (HDACs), increased histone-H3K9 acetylation in human cells, and caused changes in gene expression in both Drosophila and mice. Diacetyl crosses the blood-brain barrier and exposure caused modulation of gene expression in the mouse brain, therefore showing potential as a neuro-therapeutic. Using two separate disease models previously known to be responsive to HDAC inhibitors, we evaluated the physiological effects of volatile exposure. Diacetyl exposure halted proliferation of a neuroblastoma cell line in culture. Exposure to diacetyl vapors slowed progression of neurodegeneration in a Drosophila model for Huntington's disease. These changes strongly suggest that certain volatiles in the surroundings can have profound effects on histone acetylation, gene expression, and physiology in animals.

Plasticity of gene expression in the nervous system by exposure to environmental odorants that inhibit HDACs

Eukaryotes are often exposed to microbes and respond to their secreted metabolites, such as the microbiome in animals or commensal bacteria in roots. Little is known about the effects of long-term exposure to volatile chemicals emitted by microbes, or other volatiles that we are exposed to over a long duration. Using the model system Drosophila melanogaster, we evaluate a yeast emitted volatile, diacetyl, found in high levels around fermenting fruits where they spend long periods of time. We find that exposure to just the headspace containing the volatile molecules can alter gene expression in the antenna. Experiments showed that diacetyl and structurally related volatile compounds inhibited human histone-deacetylases (HDACs), increased histone-H3K9 acetylation in human cells, and caused wide changes in gene expression in both Drosophila and mice. Diacetyl crosses the blood-brain barrier and exposure causes modulation of gene expression in the brain, therefore has potential as a therapeutic. Using two separate disease models known to be responsive to HDAC-inhibitors, we evaluated physiological effects of volatile exposure. First, we find that the HDAC inhibitor also halts proliferation of a neuroblastoma cell line in culture as predicted. Next, exposure to vapors slows progression of neurodegeneration in a Drosophila model for Huntington's disease. These changes strongly suggest that unbeknown to us, certain volatiles in the surroundings can have profound effects on histone acetylation, gene expression and physiology in animals.

Acid-base and electrolyte evaluation in dogs with upper GI obstruction: 115 dogs (2015-2021)

OBJECTIVES

Metabolic alkalosis, although uncommon in small animals, has been previously associated with gastrointestinal obstructions. Depending on the population and disease process evaluated, previous prevalence of metabolic alkalosis is reported as ranging from 2% to 45% in canine patients. The objective of this study was to determine the prevalence of metabolic alkalosis and other acid-base and electrolyte disorders in a cohort of dogs with a confirmed upper gastrointestinal obstruction.

MATERIALS AND METHODS

Electronic medical records were reviewed to identify dogs who presented for vomiting with evidence of an upper gastrointestinal obstruction from January 2015 to October 2021. Patients were enrolled only if a preoperative venous blood gas was obtained and analysed in house. Traditional acid-base analysis was utilised to determine an acid-base status before relieving the obstruction. When available, post-operative venous acid-base status was determined within 24 hours after surgery, and compared to preoperative results.

RESULTS

A total of 115 dogs were included in the study. Twenty-five out of 115 (22%) dogs displayed either a simple metabolic alkalosis or a mixed acid-base disturbance before surgery. Twenty-seven out of 115 dogs (37%) had a normal acid-base status at entry. Seventy-one dogs had pre- and post-operative venous blood gas results available. Metabolic alkalosis was resolved in nearly all patients post-operatively, with no patients displaying a simple metabolic alkalosis. A mixed metabolic acidosis and respiratory alkalosis was the most common condition post-operatively, found in 25 of 71 (35%) dogs. Severe derangements of electrolytes were infrequent preoperatively (3/115; 2.6%). A majority of patients in this study exhibited hypokalaemia (64.4%), hypochloraemia (72.8%) and hyponatraemia (77.4%) on preoperative venous blood gases. Venous pH, Pv CO2 , bicarbonate and base excess were significantly higher preoperatively when compared to the post-operative results.

CLINICAL SIGNIFICANCE

This study found the prevalence of pre-operative metabolic alkalosis in dogs with a documented upper gastrointestinal obstruction to be lower than previously reported. Surgical or endoscopic alleviation of the upper gastrointestinal obstruction resulted in resolution of metabolic alkalosis in nearly all patients.

Tissue-specific knockout in Drosophila neuromuscular system reveals ESCRT's role in formation of synapse-derived extracellular vesicles

Tissue-specific gene knockout by CRISPR/Cas9 is a powerful approach for characterizing gene functions in animal development. However, this approach has been successfully applied in only a small number of Drosophila tissues. The Drosophila motor nervous system is an excellent model system for studying the biology of neuromuscular junction (NMJ). To expand tissue-specific CRISPR to the Drosophila motor system, here we present a CRISPR-mediated tissue-restricted mutagenesis (CRISPR-TRiM) toolkit for knocking out genes in motoneurons, muscles, and glial cells. We validated the efficacy of this toolkit by knocking out known genes in each tissue, demonstrated its orthogonal use with the Gal4/UAS binary expression system, and showed simultaneous knockout of multiple redundant genes. Using these tools, we discovered an essential role for SNARE pathways in NMJ maintenance. Furthermore, we demonstrate that the canonical ESCRT pathway suppresses NMJ bouton growth by downregulating the retrograde Gbb signaling. Lastly, we found that axon termini of motoneurons rely on ESCRT-mediated intra-axonal membrane trafficking to lease extracellular vesicles at the NMJ.

Excess glutamate release triggers subunit-specific homeostatic receptor scaling

Ionotropic glutamate receptors (GluRs) are targets for modulation in Hebbian and homeostatic synaptic plasticity and are remodeled by development, experience, and disease. We have probed the impact of synaptic glutamate levels on the two postsynaptic GluR subtypes at the Drosophila neuromuscular junction, GluRA and GluRB. We first demonstrate that GluRA and GluRB compete to establish postsynaptic receptive fields, and that proper GluR abundance and composition can be orchestrated in the absence of any synaptic glutamate release. However, excess glutamate adaptively tunes postsynaptic GluR abundance, echoing GluR scaling observed in mammalian systems. Furthermore, when GluRA vs. GluRB competition is eliminated, GluRB becomes insensitive to glutamate modulation. In contrast, GluRA is now homeostatically regulated by excess glutamate to maintain stable miniature activity, where Ca2+ permeability through GluRA receptors is required. Thus, excess glutamate, GluR competition, and Ca2+ signaling collaborate to selectively target GluR subtypes for homeostatic regulation at postsynaptic compartments.

Physiologic and Nanoscale Distinctions Define Glutamatergic Synapses in Tonic vs Phasic Neurons

Neurons exhibit a striking degree of functional diversity, each one tuned to the needs of the circuitry in which it is embedded. A fundamental functional dichotomy occurs in activity patterns, with some neurons firing at a relatively constant "tonic" rate, while others fire in bursts, a "phasic" pattern. Synapses formed by tonic versus phasic neurons are also functionally differentiated, yet the bases of their distinctive properties remain enigmatic. A major challenge toward illuminating the synaptic differences between tonic and phasic neurons is the difficulty in isolating their physiological properties. At the Drosophila neuromuscular junction, most muscle fibers are coinnervated by two motor neurons: the tonic "MN-Ib" and phasic "MN-Is." Here, we used selective expression of a newly developed botulinum neurotoxin transgene to silence tonic or phasic motor neurons in Drosophila larvae of either sex. This approach highlighted major differences in their neurotransmitter release properties, including probability, short-term plasticity, and vesicle pools. Furthermore, Ca2+ imaging demonstrated ∼2-fold greater Ca2+ influx at phasic neuron release sites relative to tonic, along with an enhanced synaptic vesicle coupling. Finally, confocal and super-resolution imaging revealed that phasic neuron release sites are organized in a more compact arrangement, with enhanced stoichiometry of voltage-gated Ca2+ channels relative to other active zone scaffolds. These data suggest that distinctions in active zone nano-architecture and Ca2+ influx collaborate to differentially tune glutamate release at tonic versus phasic synaptic subtypes.SIGNIFICANCE STATEMENT "Tonic" and "phasic" neuronal subtypes, based on differential firing properties, are common across many nervous systems. Using a recently developed approach to selectively silence transmission from one of these two neurons, we reveal specialized synaptic functional and structural properties that distinguish these specialized neurons. This study provides important insights into how input-specific synaptic diversity is achieved, which could have implications for neurologic disorders that involve changes in synaptic function.

Exercise Preferences, Barriers, and Facilitators of Individuals With Cancer Undergoing Chemotherapy Before Stem Cell Transplantation: A Mixed-Methods Study

BACKGROUND

Exercise can help mitigate side effects of hematopoietic stem cell transplantation (HSCT), particularly when initiated before HSCT. However, the exercise-related barriers, facilitators, and preferences of this population remain unclear.

OBJECTIVE

This study aimed to explore the patient experience to inform future implementation of a prehabilitation intervention.

INTERVENTIONS/METHODS

A 2-phase sequential explanatory mixed-methods study was conducted using (1) cross-sectional survey and (2) focus groups. Survey questions aligned with the Theoretical Domains Framework. Focus group data were analyzed using a directed content analysis approach, followed by inductive thematic analysis to generate themes that represented the exercise-related barriers, facilitators, and preferences of participants.

RESULTS

Twenty-six participants completed phase 1 (n = 22 with multiple myeloma). Fifty percent of participants (n = 13) were fairly/very confident in their ability to exercise pre-HSCT. Eleven participants completed phase 2. Exercise barriers included knowledge/skill limitations, inadequate healthcare provider support, and the emotional toll of treatment. Facilitators included social support and goals. Exercise preferences were related to 2 themes: (1) program structure (subthemes: prescription and scheduling, mode of delivery) and (2) support (subthemes: support from personnel, tailoring, and education).

CONCLUSION

Key exercise-related barriers included knowledge limitations, disease/treatment effects, and inadequate support. Prehabilitation should be tailored, flexible, and include education and a virtual or hybrid delivery model in this population.

IMPLICATIONS FOR PRACTICE

Nurses are well positioned to identify functional limitations and counsel and refer patients to exercise programming and/or physiotherapy services. Including an exercise professional in the pretransplant care team would provide key supportive care assistance for the nursing team.

Healthy Human Laryngopharyngeal Sensory Innervation Density Correlates with Age

OBJECTIVE

Somatosensory feedback from upper airway structures is essential for swallowing and airway defense but little is known about the identities and distributions of human upper airway neurons. Furthermore, whether sensory innervation modifies with aging is unknown. In this study, we quantify neuronal and chemosensory cell density in upper airway structures and correlate with age.

METHODS

Participants underwent biopsies from base of tongue, lateral and midline pharyngeal wall, epiglottis, and arytenoids (N = 25 13 female/12 male; 20-80 years, mean 51.4 years without clinical diagnosis of dysphagia or clinical indication for biopsy). Tissue sections were labeled with antibodies for all neurons, myelinated neurons, and chemosensory cells. Densities of lamina propria innervation, epithelial innervation, solitary chemosensory cells, and taste buds were calculated and correlated with age.

RESULTS

Arytenoid had the highest density of innervation and chemosensory cells across all measures compared to other sites. Taste buds were frequently observed in arytenoid and epiglottis. Base of tongue, lateral pharynx, and midline posterior pharynx had minimal innervation and few chemosensory cells. Epithelial innervation was present primarily in close proximity to chemosensory cells and taste buds. Overall innervation and myelinated fibers in the arytenoid lamina propria decline with aging.

CONCLUSION

Findings establish the architecture of healthy adult sensory innervation and demonstrate the varied distribution of laryngopharyngeal innervation, necessary steps toward understanding the sensory basis for swallowing and airway defense. We also document age-related decline in arytenoid innervation density. These findings suggest that sensory afferent denervation of the upper airway may be a contributing factor to presbyphagia.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:773-784, 2023.

PIKFYVE inhibition mitigates disease in models of diverse forms of ALS

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that results from many diverse genetic causes. Although therapeutics specifically targeting known causal mutations may rescue individual types of ALS, these approaches cannot treat most cases since they have unknown genetic etiology. Thus, there is a pressing need for therapeutic strategies that rescue multiple forms of ALS. Here, we show that pharmacological inhibition of PIKFYVE kinase activates an unconventional protein clearance mechanism involving exocytosis of aggregation-prone proteins. Reducing PIKFYVE activity ameliorates ALS pathology and extends survival of animal models and patient-derived motor neurons representing diverse forms of ALS including C9ORF72, TARDBP, FUS, and sporadic. These findings highlight a potential approach for mitigating ALS pathogenesis that does not require stimulating macroautophagy or the ubiquitin-proteosome system.

An Observational Cohort Study of the Role of Level of Effort in Post-Acute Brain Injury Rehabilitation

OBJECTIVE

To investigate the role of participant level of effort (LoE) on outcome in post-acute brain injury rehabilitation with the hypothesis that greater effort is associated with more positive outcomes.

DESIGN

Observational cohort study.

SETTING

Comprehensive integrated rehabilitation program for brain injury within a skilled nursing facility.

PARTICIPANTS

Consecutive admissions with acquired brain injury (N=101).

INTERVENTIONS

Individualized interdisciplinary brain injury rehabilitation; therapist rating of participant LoE with Acquired Brain Injury LoE Scale (ABI-LoES) during physical therapy, occupational therapy, and speech and language pathology sessions.

MAIN OUTCOME MEASURES

Mayo-Portland Adaptability Inventory, fourth edition (MPAI-4); Supervision Rating Scale (SRS).

RESULTS

Linear regression showed that discharge MPAI-4 Total T scores were significantly associated with mean ABI-LoES rating, admission MPAI-4 Total T scores, age at admission, and days from injury but not with standard deviation of ABI-LoES rating, sex, injury type, length of stay, or treatment before or during the COVID-19 pandemic. Discharge SRS scores were significantly associated with mean ABI-LoES rating, admission SRS scores, and age. A 1-unit increase in mean ABI-LoES rating was associated with 5.1-unit lower discharge MPAI-4 Total T scores and 1.5 lower discharge SRS scores, after controlling for other variables. Logistic regression showed that the odds of achieving a minimal clinically important difference on the MPAI-4 were 8.34 times higher with each 1-unit increase in mean ABI-LoES rating after controlling for other variables. Admission MPAI-4 was negatively associated with mean ABI-LoES rating (β=-0.07, t=-8.85, P<.0001).

CONCLUSIONS

After controlling for nonmodifiable variables, average ABI-LoES rating is positively associated with outcome. Initial level of disability is negatively associated with mean ABI-LoES rating.

Results of the c-TRAK TN trial: a clinical trial utilising ctDNA mutation tracking to detect molecular residual disease and trigger intervention in patients with moderate- and high-risk early-stage triple-negative breast cancer

BACKGROUND

Post-treatment detection of circulating tumour DNA (ctDNA) in early-stage triple-negative breast cancer (TNBC) patients predicts high risk of relapse. c-TRAK TN assessed the utility of prospective ctDNA surveillance in TNBC and the activity of pembrolizumab in patients with ctDNA detected [ctDNA positive (ctDNA+)].

PATIENTS AND METHODS

c-TRAK TN, a multicentre phase II trial, with integrated prospective ctDNA surveillance by digital PCR, enrolled patients with early-stage TNBC and residual disease following neoadjuvant chemotherapy, or stage II/III with adjuvant chemotherapy. ctDNA surveillance comprised three-monthly blood sampling to 12 months (18 months if samples were missed due to coronavirus disease), and ctDNA+ patients were randomised 2 : 1 to intervention : observation. ctDNA results were blinded unless patients were allocated to intervention, when staging scans were done and those free of recurrence were offered pembrolizumab. A protocol amendment (16 September 2020) closed the observation group; all subsequent ctDNA+ patients were allocated to intervention. Co-primary endpoints were (i) ctDNA detection rate and (ii) sustained ctDNA clearance rate on pembrolizumab (NCT03145961).

RESULTS

Two hundred and eight patients registered between 30 January 2018 and 06 December 2019, 185 had tumour sequenced, 171 (92.4%) had trackable mutations, and 161 entered ctDNA surveillance. Rate of ctDNA detection by 12 months was 27.3% (44/161, 95% confidence interval 20.6% to 34.9%). Seven patients relapsed without prior ctDNA detection. Forty-five patients entered the therapeutic component (intervention n = 31; observation n = 14; one observation patient was re-allocated to intervention following protocol amendment). Of patients allocated to intervention, 72% (23/32) had metastases on staging at the time of ctDNA+, and 4 patients declined pembrolizumab. Of the five patients who commenced pembrolizumab, none achieved sustained ctDNA clearance.

CONCLUSIONS

c-TRAK TN is the first prospective study to assess whether ctDNA assays have clinical utility in guiding therapy in TNBC. Patients had a high rate of metastatic disease on ctDNA detection. Findings have implications for future trial design, emphasising the importance of commencing ctDNA testing early, with more sensitive and/or frequent ctDNA testing regimes.

A glutamate receptor C-tail recruits CaMKII to suppress retrograde homeostatic signaling

Presynaptic homeostatic plasticity (PHP) adaptively enhances neurotransmitter release following diminished postsynaptic glutamate receptor (GluR) functionality to maintain synaptic strength. While much is known about PHP expression mechanisms, postsynaptic induction remains enigmatic. For over 20 years, diminished postsynaptic Ca2+ influx was hypothesized to reduce CaMKII activity and enable retrograde PHP signaling at the Drosophila neuromuscular junction. Here, we have interrogated inductive signaling and find that active CaMKII colocalizes with and requires the GluRIIA receptor subunit. Next, we generated Ca2+-impermeable GluRs to reveal that both CaMKII activity and PHP induction are Ca2+-insensitive. Rather, a GluRIIA C-tail domain is necessary and sufficient to recruit active CaMKII. Finally, chimeric receptors demonstrate that the GluRIIA tail constitutively occludes retrograde homeostatic signaling by stabilizing active CaMKII. Thus, the physical loss of the GluRIIA tail is sensed, rather than reduced Ca2+, to enable retrograde PHP signaling, highlighting a unique, Ca2+-independent control mechanism for CaMKII in gating homeostatic plasticity.

Understanding consequences and tradeoffs of melt processing as a pretreatment for enzymatic depolymerization of poly(ethylene terephthalate)

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Evolution of vertebrate respiratory central rhythm generators

Tracing the evolution of the central rhythm generators associated with ventilation in vertebrates is hindered by a lack of information surrounding key transitions. To begin with, central rhythm generation has been studied in detail in only a few species from four vertebrate groups, lamprey, anuran amphibians, turtles, and mammals (primarily rodents). Secondly, there is a lack of information regarding the transition from water breathing fish to air breathing amniotes (reptiles, birds, and mammals). Specifically, the respiratory rhythm generators of fish appear to be single oscillators capable of generating both phases of the respiratory cycle (expansion and compression) and projecting to motoneurons in cranial nerves innervating bucco-pharyngeal muscles. In the amniotes we find oscillators capable of independently generating separate phases of the respiratory cycle (expiration and inspiration) and projecting to pre-motoneurons in the ventrolateral medulla that in turn project to spinal motoneurons innervating thoracic and abdominal muscles (reptiles, birds, and mammals). Studies of the one group of amphibians that lie at this transition (the anurans), raise intriguing possibilities but, for a variety of reasons that we explore, also raise unanswered questions. In this review we summarize what is known about the rhythm generating circuits associated with breathing that arise from the different rhombomeric segments in each of the different vertebrate classes. Assuming oscillating circuits form in every pair of rhombomeres in every vertebrate during development, we trace what appears to be the evolutionary fate of each and highlight the questions that remain to be answered to properly understand the evolutionary transitions in vertebrate central respiratory rhythm generation.

Engineering skeletal muscle tissues with advanced maturity improves synapse formation with human induced pluripotent stem cell-derived motor neurons

To develop effective cures for neuromuscular diseases, human-relevant in vitro models of neuromuscular tissues are critically needed to probe disease mechanisms on a cellular and molecular level. However, previous attempts to co-culture motor neurons and skeletal muscle have resulted in relatively immature neuromuscular junctions (NMJs). In this study, NMJs formed by human induced pluripotent stem cell (hiPSC)-derived motor neurons were improved by optimizing the maturity of the co-cultured muscle tissue. First, muscle tissues engineered from the C2C12 mouse myoblast cell line, cryopreserved primary human myoblasts, and freshly isolated primary chick myoblasts on micromolded gelatin hydrogels were compared. After three weeks, only chick muscle tissues remained stably adhered to hydrogels and exhibited progressive increases in myogenic index and stress generation, approaching values generated by native muscle tissue. After three weeks of co-culture with hiPSC-derived motor neurons, engineered chick muscle tissues formed NMJs with increasing co-localization of pre- and postsynaptic markers as well as increased frequency and magnitude of synaptic activity, surpassing structural and functional maturity of previous in vitro models. Engineered chick muscle tissues also demonstrated increased expression of genes related to sarcomere maturation and innervation over time, revealing new insights into the molecular pathways that likely contribute to enhanced NMJ formation. These approaches for engineering advanced neuromuscular tissues with relatively mature NMJs and interrogating their structure and function have many applications in neuromuscular disease modeling and drug development.

O65: C-MET PROTEIN AS A COLORECTAL CANCER BIOMARKER FOR FLUORESCENCE IMAGE-GUIDED SURGERY

Introduction

The c-Met transmembrane protein is vital for cell differentiation and migration and is overexpressed in many gastrointestinal cancers. This study aimed to investigate a novel c-Met targeted peptide coupled to a fluorophore (EMI-137, Edinburgh Molecular Imaging Ltd.) for use in fluorescence image-guided colorectal cancer (CRC) surgery.

Method

A high c-Met expressing cell-line, HT29, was identified with temporary RNA suppression and used to develop a mouse xenograph CRC model. Tumours were allowed to grow to 10mm. EMI-137 was injected into the tail vein and biodistribution analysed using the IVIS system.

Nine patients undergoing elective surgery for colon cancer received a single IV dose EMI-137 1-3 hours before surgery. Tumour and LN fluorescence was assessed with a prototype Karl Storz laparoscope. Intraoperative fluorescence was correlated with radiological and pathological TNM stage and tissue c-Met expression using immunohistochemistry.

Result

The HT29 xenograph CRC model demonstrated selective EMI-137 uptake and fluorescence 1- 6 hours post administration. Nine participants aged 67-77 years received EMI-137 106 minutes (S.D±17) before surgery. Marked background fluorescence was observed in all patients. 4/9 (44%) patients showed mild increase in tumour fluorescence over background. 5/9 patients had histological LN disease, but no fluorescent nodes were detected intraoperatively. There was no correlation with T-stage. At histopathological assessment 8/9 participants showed moderate or high tumour c-Met expression. 8/8 malignant LNs demonstrated high c-Met expression.

Conclusion

EMI-137 is specific for human c-Met in 2D and xenograph CRC models. EMI-137 is safe for human use but its utility is limited by insufficient tumour-to-background ratios.

Take-home message

This first-in-man study of a novel fluorescent peptide targeted to the c-Met receptor, found EMI-137 lacked the sensitivity and specificity to accurately map the tumour margins and lymph node burden in laparoscopic colonic cancer resection surgery.

Clinical utility of liver biopsies in dogs undergoing splenectomy

OBJECTIVE

To determine the prevalence of neoplasia detected on liver biopsy obtained at the time of splenectomy in dogs with splenic masses.

MATERIALS AND METHODS

Retrospective study of medical records of dogs with splenic masses from which liver biopsies were taken following splenectomy.

RESULTS

Malignant splenic neoplasia was detected in 50 of 113 (44.2%) of the dogs undergoing splenectomy. Neoplastic liver disease was detected on biopsy from 1 of 40 (2.5%) dogs with a grossly normal liver and from 20 of 69 (28.9%) dogs with a grossly abnormal liver. Dogs with a grossly abnormal liver had a ~ 16 times (95% CI: 2.5-170) higher chance of being diagnosed with liver neoplasia on biopsy. Haemoabdomen was also associated with an increased likelihood of liver neoplasia on biopsy at the time of splenectomy.

CLINICAL SIGNIFICANCE

A liver biopsy taken from grossly normal liver is a low-yield diagnostic test but liver biopsy is recommended following splenectomy if the liver appears abnormal at surgery.

Developmental arrest of Drosophila larvae elicits presynaptic depression and enables prolonged studies of neurodegeneration

Synapses exhibit an astonishing degree of adaptive plasticity in healthy and disease states. We have investigated whether synapses also adjust to life stages imposed by novel developmental programs for which they were never molded by evolution. Under conditions in which Drosophila larvae are terminally arrested, we have characterized synaptic growth, structure and function at the neuromuscular junction (NMJ). Although wild-type larvae transition to pupae after 5 days, arrested third instar (ATI) larvae persist for 35 days, during which time NMJs exhibit extensive overgrowth in muscle size, presynaptic release sites and postsynaptic glutamate receptors. Remarkably, despite this exuberant growth, stable neurotransmission is maintained throughout the ATI lifespan through a potent homeostatic reduction in presynaptic neurotransmitter release. Arrest of the larval stage in stathmin mutants also reveals a degree of progressive instability and neurodegeneration that was not apparent during the typical larval period. Hence, an adaptive form of presynaptic depression stabilizes neurotransmission during an extended developmental period of unconstrained synaptic growth. More generally, the ATI manipulation provides a powerful system for studying neurodegeneration and plasticity across prolonged developmental timescales.

Thyroid storm with encephalopathy and cardiovascular symptoms refractory to medical management in an adolescent

Thyroid storm (TS) is rare in pediatrics, most cases reported in literature responded well to medical therapy. We report the case of an adolescent female presented with TS refractory to anti-thyroid medical management. She had refractory hypertension, tachycardia, and progressive encephalopathy despite aggressive medical management. She underwent subtotal thyroidectomy after 2 weeks of failed medical management with a complete resolution of symptoms within days of surgery. We also learned sodium nitroprusside with its direct vasodilatory effect on conduit vessels, verapamil with its rate control properties, and labetalol with its dual sympathetic blockage property were beneficial in the management of this patient.

Cul3 and insomniac are required for rapid ubiquitination of postsynaptic targets and retrograde homeostatic signaling

At the Drosophila neuromuscular junction, inhibition of postsynaptic glutamate receptors activates retrograde signaling that precisely increases presynaptic neurotransmitter release to restore baseline synaptic strength. However, the nature of the underlying postsynaptic induction process remains enigmatic. Here, we design a forward genetic screen to discover factors in the postsynaptic compartment necessary to generate retrograde homeostatic signaling. This approach identified insomniac (inc), a putative adaptor for the Cullin-3 (Cul3) ubiquitin ligase complex, which together with Cul3 is essential for normal sleep regulation. Interestingly, we find that Inc and Cul3 rapidly accumulate at postsynaptic compartments following acute receptor inhibition and are required for a local increase in mono-ubiquitination. Finally, we show that Peflin, a Ca²⁺-regulated Cul3 co-adaptor, is necessary for homeostatic communication, suggesting a relationship between Ca²⁺ signaling and control of Cul3/Inc activity in the postsynaptic compartment. Our study suggests that Cul3/Inc-dependent mono-ubiquitination, compartmentalized at postsynaptic densities, gates retrograde signaling and provides an intriguing molecular link between the control of sleep and homeostatic plasticity at synapses.

The authors use a forward genetic screen to discover postsynaptic factors required for homeostatic synaptic plasticity at the Drosophila neuromuscular junction. They identify insomniac and the ubiquitin ligase Cul3, genes involved in sleep regulation, to be necessary for retrograde homeostatic signalling at this synapse.

Detection of Airway Invasion During Flexible Endoscopic Evaluations of Swallowing: Comparing Barium, Blue Dye, and Green Dye

Purpose The aim of this study was to assess the effects of barium, blue dye, and green dye on the frequency and reliability of detecting airway invasion (penetration and aspiration) seen during flexible endoscopic evaluations of swallowing (FEES). Method Thirty patients with neurodegenerative disease and suspected dysphagia underwent an FEES. Patients were presented with 10-cc boluses of water colored with blue dye, green dye, and barium, within the same examination, in a randomized order. Airway protection outcomes were blindly analyzed by a panel of expert raters. Outcomes included the presence of residue on airway structures (epiglottis, laryngeal vestibule, vocal folds, subglottis) and abnormal Penetration-Aspiration Scale (PAS; Rosenbek, Robbins, Roecker, Coyle, & Wood, 1996 ) scores (PAS ≥ 3). Statistical analyses were performed to determine group differences in the frequency of airway residue and abnormal PAS scores, as well as reliability. Results Airway residue was observed most frequently with barium when compared to blue dye ( p < .05) or green dye ( p < .05). Abnormal PAS scores were also observed most frequently with barium when compared to blue dye ( p < .0005) and green dye ( p < .0005). There were no significant differences in the observed frequency of airway residue nor abnormal PAS scores when comparing blue and green dye ( p > .05). Intrapanel reliability scores for airway residue and PAS scores, respectively, were very good ( k = .83) and good ( k = .67) for barium, very good ( k = 1.00) and moderate ( k = .50) for green dye, and moderate ( k = .47) and fair ( k = .33) for blue dye. Conclusion Airway invasion was detected significantly more frequently and with greater reliability with barium when compared to blue and green dye. Given these findings, standardized use of barium is recommended at some point during FEES, especially when attempting to detect subtle signs of airway invasion.

Arginine Metabolism in Supragingival Oral Biofilms as a Potential Predictor of Caries Risk

INTRODUCTION

Ammonia production via the arginine deiminase system (ADS) of oral bacteria can function to reduce the cariogenicity of oral biofilms by neutralizing glycolytic acids that cause tooth demineralization.

OBJECTIVES

This cohort study investigated the relationship between ADS activity and bacterial profile changes of supragingival biofilms with caries experience among children over time.

METHODS

A total of 79 children aged 2 to 7 y at baseline were assessed every 6 mo for a period of 18 mo. Children were grouped as caries free (CF), caries active with enamel lesions (CAE), or caries active with dentin lesions (CA). Supragingival plaque samples were collected from caries-free surfaces (PF) and from enamel (PE) and dentin (PD) lesions. Plaque ADS activity was measured by monitoring citrulline production from arginine and compared with ribosomal 16S rRNA-derived taxonomic profiles for the same samples.

RESULTS

At baseline, 37% of the children were CF, 34% CAE, and 29% CA. At 18 mo, 26% were CF, 41% CAE, 23% CA, and 10% were caries experienced (new restorations but no caries activity). Throughout the study period, ADS activity was significantly higher in the CF group than the CA group (P < 0.0001), and ADS activity in the PF samples was significantly higher than in the PE and PD samples (P < 0.0001). Distance-based redundancy analysis showed that the bacterial communities could be differentiated when plaque samples are grouped into levels of high and low ADS activity.

CONCLUSIONS

There is a positive correlation between caries activity and low arginolytic capacity of the supragingival oral biofilms of children and tooth surfaces over time. Measurements of arginine metabolism via ADS may be useful to differentiate the caries risk of individuals and tooth surfaces.

KNOWLEDGE TRANSFER STATEMENT

Findings from this study support the development of new strategies for caries risk assessment and prevention based on modulation of the virulence of the oral microbiome through arginine metabolism in supragingival biofilms.

Abstract GS3-02: PALLET: A neoadjuvant study to compare the clinical and antiproliferative effects of letrozole with and without palbociclib

Background: CDK4/6 inhibitors, such as palbociclib, are used to treat ER+ metastatic breast cancer in combination with endocrine therapy with trials ongoing in patients with primary disease. No biomarkers exist to identify those who do/do not benefit from added CDK4/6 inhibition. PALLET is an investigator-initiated/led phase II randomized trial collaboration between UK and NSABP investigators evaluating the biological and clinical effects of palbociclib with letrozole combination as neoadjuvant therapy.

Methods: Postmenopausal women with ER+ primary breast cancer and tumors &gt;2.0cm (ultrasound) were randomized to one of 4 treatment groups (3:2:2:2 ratio): Group A: letrozole (2.5mg/d) for 14 weeks; Group B: letrozole for 2 weeks followed by letrozole + palbociclib to 14 weeks; Group C: palbociclib for 2 weeks followed by letrozole + palbociclib to 14 weeks; Group D: letrozole + palbociclib for 14 weeks. Palbociclib was given 125mg/d PO on a 21 days on, 7 days off schedule. Post-14 week treatment was at the discretion of the treating clinician including letrozole until surgery. Core-cut biopsies were taken at baseline, 2 weeks and 14 weeks. Co-primary endpoints for letrozole alone vs palbociclib groups (Group A vs Groups B+C+D) were: (i) change in Ki67 (IHC) between baseline and 14 weeks (log-fold change, Mann-Whitney test); (ii) clinical response (ultrasound) after 14 weeks (4 group, ordinal, Mann-Whitney test). Complete cell-cycle arrest (CCCA) (Ki67≤2.7%) was analyzed using a logistic regression model adjusting for recruitment region. Pre-specified exploratory biomarkers included c-PARP (apoptosis).

Results: 307 patients were recruited between 27 Feb 2015 and 08 Mar 2018; 103 were randomized to letrozole alone and 204 to letrozole + palbociclib. 279 (90.9%) patients were evaluable for 14 week clinical response. Clinical response was not significantly different between letrozole vs letrozole + palbociclib groups [(p=0.20; CR+PR 49.5% (46/93) vs 54.3% (101/186) and PD 5.4% (5/93) vs 3.2% (6/186)] nor was the small proportion of patients with pathological CR (1/87, 1.1% vs 6/180, 3.3%; p=0.43). 190 (61.9%) patients were evaluable for 14 week change in Ki67. The median log-fold change in Ki67 was greater with letrozole + palbociclib vs letrozole alone (-4.1 vs -2.2; p&lt;0.001) corresponding to a geometric mean change of -97.4% vs -88.5%. Similarly, a greater proportion of patients who received letrozole + palbociclib achieved CCCA (90% vs 59%, p&lt;0.001). 146 (47.6%) patients were evaluable for c-PARP and the log-fold change (suppression) was greater with letrozole + palbociclib vs letrozole alone (-0.80 vs -0.42; p=0.003) corresponding to a geometric mean change of -56.8% vs -31.4%. Other biomarkers of response / resistance are being evaluated. A higher proportion of patients had a grade ≥3 toxicity on letrozole + palbociclib than letrozole alone (49.8% vs 17.0%; p&lt;0.001) mainly due to asymptomatic neutropenia.

Conclusion: Adding palbociclib to letrozole markedly enhanced the suppression of malignant cell proliferation as assessed by Ki67 but did not substantially increase the clinical response of primary ER+ breast cancer over a 14-week period. Concurrent reductions in cell death may have reduced the speed of tumor shrinkage.

Citation Format: Dowsett M, Jacobs S, Johnston S, Bliss J, Wheatley D, Holcombe C, Stein R, McIntosh S, Barry P, Dolling D, Snowdon C, Perry S, Batten L, Dodson A, Martins V, Modi A, Cornman C, Puhalla S, Wolmark N, Julian T, Pogue-Geile K, Robidoux A, Provencher L, Boileau JF, Shalaby I, Thirlwell M, Fisher K, Huang Bartlett C, Koehler M, Osborne K, Rimawi M. PALLET: A neoadjuvant study to compare the clinical and antiproliferative effects of letrozole with and without palbociclib [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS3-02.

Factors influencing medical student self-competence to provide weight management services

This study aimed to identify factors associated with high obesity care self-competence among US medical students. The authors performed a cross-sectional analysis of 2014 survey data on fourth year medical students collected online as part of the Medical Student Cognitive Habits and Growth Evaluation Study (CHANGES). Independent variables included quality and quantity of interaction with patients and peers with obesity; hours of communication and partnership skills training; negative remarks against patients with obesity by supervising physicians, and witnessed discrimination against patients with obesity. The dependent variable was self-competence in providing obesity care. Of 5823 students invited to participate, 3689 (63%) responded and were included in our analyses. Most students were white (65%), half were women and 42% had high self-competence in caring for patients with obesity. Factors associated with high self-competence included increased interaction with peers with obesity (39% vs. 49%, P < 0.001) and increased partnership skills training (32% vs. 61%, P < 0.001). Increased partnership skills training and quantity of interactions with peers with obesity were associated with high student self-competence in providing obesity-related care to patients. Medical schools might consider increasing partnership skills training to improve students' preparedness and skill in performing obesity-related care.

Multidrug-resistant Aeromonas hydrophila causing fatal bilateral necrotizing fasciitis in an immunocompromised patient: a case report

BACKGROUND

Aeromonas hydrophila is a water-dwelling, gram-negative rod-shaped bacterium, associated with diarrheal illness and, less commonly, necrotizing skin and soft tissue infections, especially among immunocompromised patients. Necrotizing fasciitis is associated with a high mortality rate, especially when caused by Aeromonas spp. Our patient was infected with an extremely aggressive form of multidrug-resistant Aeromonas spp. that produced both an extended-spectrum β-lactamase and an AmpC enzyme. Aeromonads are being recognized as important emerging pathogens because of their inherent antibiotic resistance profiles compounded by other virulence factors. These difficult-to-treat organisms can have significant implications in both clinical and public health settings.

CASE PRESENTATION

A 37-year-old Caucasian male with immunosuppression due to aplastic anemia being treated with cyclosporine, presented to hospital with relapsed disease. While in hospital, he subsequently developed overwhelming sepsis secondary to bilateral lower extremity necrotizing fasciitis. The necrotizing fasciitis was caused by a multidrug-resistant strain of A. hydrophila. Despite broad-spectrum antibiotics and aggressive surgical debridement, he succumbed to this severe invasive infection.

CONCLUSIONS

Necrotizing fasciitis caused by Aeromonas spp. is a rare infection that may have a poor clinical outcome, particularly if the diagnosis is delayed and/or the organism is highly virulent and multidrug resistant. Enhanced education of clinicians and microbiologists is required to prevent unnecessary complications and improve survival.

Marine Carbonates in the Mantle Source of Oceanic Basalts: Pb Isotopic Constraints

For almost fifty years, geochemists have been interpreting the clues from Pb isotopic ratios concerning mantle composition and evolution separately. The Pb isotopes of ocean island basalts (OIB) indicate that their mantle source is heterogeneous, most likely due to the presence of end-components derived from recycled crust and sediment. Some OIB have unusually high 206Pb/204Pb coming from one of the end-components with a long time-integrated high 238U/204Pb or μ (HIMU). Most OIB and many mid-ocean ridge basalts (MORB) also have high 206Pb/204Pb, indicating a HIMU-like source. Moreover, measured 232Th/238U (κ) for most MORB are lower than those deduced from their 208Pb/204Pb and 206Pb/204Pb. Such high μ and low κ features of oceanic basalts are inconsistent with the known geochemical behavior of U, Pb and Th and temporal evolution of the mantle; these have been respectively termed the 1st and 2nd Pb paradox. Here we show that subducted marine carbonates can be a source for HIMU and a solution to the Pb paradoxes. The results are consistent with the predictions of the marine carbonate recycling hypothesis that posits the Pb isotopes of oceanic basalts indicate a common origin and/or magma generation process.

A qualitative analysis of the barriers to antiretroviral therapy initiation among children 2 to 18 months of age in Swaziland

HIV/AIDS remains one of the leading causes of death among children under 5 years old in Swaziland. Although studies have shown that early initiation of infants and children diagnosed with HIV on antiretroviral therapy (ART) significantly reduces mortality, many children do not initiate ART until the later stages of disease. This study was designed to collect qualitative data from mothers and caregivers of HIV-positive children to identify the barriers to ART initiation. Focus group discussion (FGD) sessions were conducted in siSwati between July and September 2014 among caregivers of aged children 2-18 months in Swaziland who did or did not initiate ART between January 2011 and December 2012 after HIV DNA PCR-positive diagnosis of the infants. Denial, guilt, lack of knowledge, tuberculosis (TB)/HIV co-infection, HIV-related stigma, lack of money, and distance to clinics were reported by the participants as barriers to ART initiation. The findings further revealed that non-initiation on ART was not linked to a negative perception of the treatment. Findings suggest a need to improve sensitivity among healthcare workers as well as education and counselling services that will facilitate the ART initiation process.

Homeostatic plasticity can be induced and expressed to restore synaptic strength at neuromuscular junctions undergoing ALS-related degeneration

Amyotrophic lateral sclerosis (ALS) is debilitating neurodegenerative disease characterized by motor neuron dysfunction and progressive weakening of the neuromuscular junction (NMJ). Hereditary ALS is strongly associated with variants in the human C9orf72 gene. We have characterized C9orf72 pathology at the Drosophila NMJ and utilized several approaches to restore synaptic strength in this model. First, we demonstrate a dramatic reduction in synaptic arborization and active zone number at NMJs following C9orf72 transgenic expression in motor neurons. Further, neurotransmission is similarly reduced at these synapses, consistent with severe degradation. However, despite these defects, C9orf72 synapses still retain the ability to express presynaptic homeostatic plasticity, a fundamental and adaptive form of NMJ plasticity in which perturbation to postsynaptic neurotransmitter receptors leads to a retrograde enhancement in presynaptic release. Next, we show that these endogenous but dormant homeostatic mechanisms can be harnessed to restore synaptic strength despite C9orf72 pathogenesis. Finally, activation of regenerative signaling is not neuroprotective in motor neurons undergoing C9orf72 toxicity. Together, these experiments define synaptic dysfunction at NMJs experiencing ALS-related degradation and demonstrate the potential to activate latent plasticity as a novel therapeutic strategy to restore synaptic strength.

Assessing the safety culture of care homes: a multimethod evaluation of the adaptation, face validity and feasibility of the Manchester Patient Safety Framework

BACKGROUND

Understanding the cultural characteristics of healthcare organisations is widely recognised to be an important component of patient safety. A growing number of vulnerable older people are living in care homes but little attention has been paid to safety culture in this sector. In this study, we aimed to adapt the Manchester Patient Safety Framework (MaPSaF), a commonly used tool in the health sector, for use in care homes and then to test its face validity and preliminary feasibility as a tool for developing a better understanding of safety culture in the sector.

METHODS

As part of a wider improvement programme to reduce the prevalence of common safety incidents among residents in 90 care homes in England, we adapted MaPSaF and carried out a multimethod participatory evaluation of its face validity and feasibility for care home staff. Data were collected using participant observation, interviews, documentary analysis and a survey, and were analysed thematically.

RESULTS

MaPSaF required considerable adaptation in terms of its length, language and content in order for it to be perceived to be acceptable and useful to care home staff. The changes made reflected differences between the health and care home sectors in terms of the local context and wider policy environment, and the expectations, capacity and capabilities of the staff. Based on this preliminary study, the adapted tool, renamed 'Culture is Key', appears to have reasonable face validity and, with adequate facilitation, it is usable by front-line staff and useful in raising their awareness about safety issues.

CONCLUSIONS

'Culture is Key' is a new tool which appears to have acceptable face validity and feasibility to be used by care home staff to deepen their understanding of the safety culture of their organisations and therefore has potential to contribute to improving care for vulnerable older people.

The Role of Histone Deacetylase 6 in Synaptic Plasticity and Memory

Histone deacetylases (HDACs) have been extensively studied as drug targets in neurodegenerative diseases, but less is known about their role in healthy neurons. We tested zinc-dependent HDACs using RNAi in Drosophila melanogaster and found memory deficits with RPD3 and HDAC6. We demonstrate that HDAC6 is required in both the larval and adult stages for normal olfactory memory retention. Neuronal expression of HDAC6 rescued memory deficits, and we demonstrate that the N-terminal deacetylase (DAC) domain is required for this ability. This suggests that deacetylation of synaptic targets associated with the first DAC domain, such as the active-zone scaffold Bruchpilot, is required for memory retention. Finally, electrophysiological experiments at the neuromuscular junction reveal that HDAC6 mutants exhibit a partial block of homeostatic plasticity, suggesting that HDAC6 may be required for the stabilization of synaptic strength. The learning deficit we observe in HDAC6 mutants could be a behavioral consequence of these synaptic defects.

Young patients and gastrointestinal (GI) tract malignancies - are we addressing the unmet needs?

Background

Recent epidemiological studies indicate the rate of gastrointestinal (GI) malignancies among younger patients is increasing, mainly due to colorectal cancer. There is a paucity of data regarding the magnitude of treatment-related symptoms, psychosocial issues and potential unmet needs in this population. We aimed to characterize the needs of this population to evaluate whether unmet needs could be targeted by potential intervention.

Methods

Female and male patients diagnosed with cancer of the gastrointestinal tract <40y retrospectively completed a questionnaire to evaluate symptoms, daily function and unmet needs at pre-treatment, during and post-treatment. Comparisons were made by gender, disease stage and treatment modality. Multiple linear regression models evaluated effects of demographics, symptoms and needs on multiple domains of health-related-quality-of-life (using Short-Form Health Survey-12 and CARES).

Results

Fifty patients were enrolled (52 % female) to a pilot study. Median age at diagnosis was 35.5y (range, 21-40y). The symptoms that significantly increased from baseline to during and post-treatment were: diarrhea (37 %), sleeping disorder (32 %) and sexual dysfunction (40 %). Patients also reported significant deterioration in occupational activities and coping with children compared with baseline. Female patients reported significant unmet need for nutritional counseling and psychosocial support compared to male patients (p < 0.05). Patients treated with multimodality-treatment presented higher rates of unmet needs (p = 0.03).

Conclusions

Young patients with GI cancers represent a group with unique characteristics and needs compared with published evidence on other young-onset malignancies. The distinctive symptoms and areas of treatment-related functional impairments indicate there are unmet needs, especially in the area of psychosocial support and nutritional counseling.

Can macrophages within the microenvironment of locally invasive rectal cancers predict response to radiotherapy?

BACKGROUND

Only half of patients with locally invasive rectal carcinoma respond to short-course preoperative radiotherapy. A predictive test enabling better patient selection could avoid unneccessary radiation exposure to poor responders. Macrophages within the tumour immune microenvironment with tumoricidal M1 and tumour-protective M2 phenotypes could be modulating this response. This study investigated the possible predictive value of M1 and M2 subpopulations in identifying patients' likely response to short-course preoperative radiotherapy.

METHODS

Biopsy samples were taken from 29 patients with locally invasive rectal carcinoma before treatment with short-course radiotherapy and surgical specimens obtained after resection following short-course preoperative radiotherapy. Dual-staining immunohistochemistry was performed with CD68 as macrophage marker, HLA-DR as M1 marker, and CD163 as M2 marker. Samples were scored for hot-and-random spots by Nuance software (version 3.0.2) and compared with patients' outcome data. Tumour response was measured by assessment of reduction of tumour-cell density.

FINDINGS

Samples revealing a low score for HLA-DR positive M1 macrophages exhibited a better response to short-course radiotherapy with up to 80% (median 80·38% [IQR 46·94-84·73]) reduction in the tumour cell density. On the other hand those with a high score exhibited a poor response with only up to 20% (20·26 [0-48·19]) reduction. The difference in response between the two groups was significant (p=0·017). No such trends were observed for CD163+ M2 macrophages. The ratio of HLA-DR+ to CD163+ macrophages for biopsy and resection samples was significantly different, showing a drop in the HLA-DR positive macrophages in the resection samples (p=0·024). The mean of the difference between the biopsy (median 2·53 [IQR 1·98-3·08]) and resection (1·38 [0·96-1·8]) was 1·15 (p=0·024).

INTERPRETATION

Patients with a variable macrophage phenotype composition within biopsy samples from patients with locally invasive rectal carcinoma respond differently to short-course preoperative radiotherapy. Further investigation involving a panel of macrophage and other immune-cell markers could verify and validate these findings and develop them as predictive tests identifying good responders to radiotherapy in patients with locally invasive rectal carcinoma.

FUNDING

None.

An observational study on the expression levels of MDM2 and MDMX proteins, and associated effects on P53 in a series of human liposarcomas

Background

Inactivation of wild type P53 by its main cellular inhibitors (MDM2 and MDMX) is a well recognised feature of tumour formation in liposarcomas. MDM2 over-expression has been detected in approximately 80% of liposarcomas but only limited information is available about MDMX over-expression. To date, we are not aware of any study that has described the patterns of MDM2 and MDMX co-expression in liposarcomas. Such information has become more pertinent as various novel MDM2 and/or MDMX single and dual affinity antagonist compounds are emerging as an alternative approach for potential targeted therapeutic strategies.

Methods

We analysed a case series of 61 fully characterized liposarcomas of various sub-types by immunohistochemistry, to assess the expression levels of P53, MDM2 and MDMX, simultaneously. P53 sequencing was performed in all cases that expressed P53 protein in 10% or more of cells to rule out mutation-related over-expression.

Results

50 cases over-expressed MDM2 and 42 of these co-expressed MDMX at varying relative levels. The relative expression levels of the two proteins with respect to each other were subtype-dependent. This apparently affected the detected levels of P53 directly in two distinct patterns. Diminished levels of P53 were observed when MDM2 was significantly higher in relation to MDMX, suggesting a dominant role for MDM2 in the degradation of P53. Higher levels of P53 were noted with increasing MDMX levels suggesting an interaction between MDM2 and MDMX that resulted in a reduced efficiency of MDM2 in degrading P53. Of the 26 cases of liposarcoma with elevated P53 expression, 5 were found to have a somatic mutation in the P53 gene.

Conclusions

The results suggest that complex dynamic interactions between MDM2 and MDMX proteins may directly affect the cellular levels of P53. This therefore suggests that careful characterization of both these markers will be necessary in tumours when considering in vivo evaluation of novel blocker compounds for MDM proteins, as a therapeutic strategy to restore wild type P53 function.