Chronic evoked seizures in young pre-symptomatic APP/PS1 mice induce serotonin changes and accelerate onset of Alzheimer's disease-related neuropathology

OBJECTIVE

Hyperexcitability is intimately linked to Alzheimer's disease (AD) pathology, but the precise timing and contributions of neuronal hyperexcitability to disease progression is unclear. Seizure induction in rodent AD models can uncover new therapeutic targets. Further, investigator-evoked seizures can directly establish how hyperexcitability and AD-associated risk factors influence neuropathological hallmarks and disease course at presymptomatic stages.

METHODS

Corneal kindling is a well-characterized preclinical epilepsy model that allows for precise control of seizure history to pair to subsequent behavioral assessments. 2-3-month-old APP/PS1, PSEN2-N141I, and transgenic control male and female mice were thus sham or corneal kindled for 2 weeks. Seizure-induced changes in glia, serotonin pathway proteins, and amyloid β levels in hippocampus and prefrontal cortex were quantified.

RESULTS

APP/PS1 females were more susceptible to corneal kindling. However, regardless of sex, APP/PS1 mice experienced extensive seizure-induced mortality versus kindled Tg- controls. PSEN2-N141I mice were not negatively affected by corneal kindling. Mortality correlated with a marked downregulation of hippocampal tryptophan hydroxylase 2 and monoamine oxidase A protein expression versus controls; these changes were not detected in PSEN2-N141I mice. Kindled APP/PS1 mice also exhibited soluble amyloid β upregulation and glial reactivity without plaque deposition.

SIGNIFICANCE

Evoked convulsive seizures and neuronal hyperexcitability in pre-symptomatic APP/PS1 mice promoted premature mortality without pathological Aβ plaque deposition, whereas PSEN2-N141I mice were unaffected. Disruptions in serotonin pathway metabolism in APP/PS1 mice was associated with increased glial reactivity without Aβ plaque deposition, demonstrating that neuronal hyperexcitability in early AD causes pathological Aβ overexpression and worsens long-term outcomes through a serotonin-related mechanism.

Diet composition and sterilization modifies intestinal microbiome diversity and burden of Theiler's virus infection-induced acute seizures

OBJECTIVE

Brain infection with Theiler's murine encephalomyelitis virus (TMEV) in C57BL/6J mice can induce acquired epileptogenesis. Diet alters acute seizure incidence in TMEV-infected mice; yet it is unclear whether intestinal dysbiosis may also impact acute or chronic behavioral comorbidities. This study thus assessed the impact of diet formulation and sterilization on acute seizure presentation, gut microbiome composition, and epilepsy-related chronic behavioral comorbidities.

METHODS

Baseline fecal samples were collected from male C57BL/6J mice (4- to 5-weeks-old; Jackson Labs) upon facility arrival. Mice were randomized to either autoclaved (AC) or irradiated diet (IR) (Prolab RMH 3000) or IR (Picolab 5053). Three days later, mice underwent intracerebral TMEV or phosphate-buffered saline (PBS) injection. Fecal samples were collected from a subset of mice at infection (Day 0) and Day 7 post-infection. Epilepsy-related working memory deficits and seizure threshold were assessed 6 weeks post-infection. Gut microbiome diversity was determined by 16S rRNA amplicon sequencing of fecal samples.

RESULTS

TMEV-infected mice displayed acute handling-induced seizures, regardless of diet: 28 of 57 IR Picolab 5053 (49.1%), 30 of 41 IR Prolab RMH 3000 (73.2%), and 47 of 77 AC Prolab RMH 3000 (61%) mice displayed seizures. The number of observed seizures differed significantly by diet: IR Picolab 5053 diet-fed mice had 2.2 ± 2.8 seizures (mean ± standard deviation), IR Prolab RMH 3000 diet-fed mice had 3.5 ± 2.9 seizures, and AC Prolab RMH 3000 diet-fed mice had 4.4 ± 3.8 seizures during the 7-day monitoring period. Gut microbiome composition differed significantly in TMEV-infected mice fed the AC Prolab RMH 3000 diet, with measured differences in gram-positive bacteria. These mice also displayed worsened long-term working memory deficits.

SIGNIFICANCE

Diet-induced differences in intestinal dysbiosis in the TMEV model are associated with marked changes in acute seizure presentation, symptomatic recovery, and onset of chronic behavioral comorbidities of epilepsy. Our study reveals a novel disease-modifying impact of dietary manipulation on intestinal bacterial species after TMEV-induced acute seizures.

Diet composition and sterilization modifies intestinal microbiome diversity and burden of Theiler's virus infection-induced acute seizures

Objective

Central nervous system infection with Theiler's murine encephalomyelitis virus (TMEV) in C57BL/6J mice can model acquired epileptogenesis. Diet alters the acute seizure incidence in TMEV-infected mice; yet it is unclear whether intestinal dysbiosis may also impact acute or chronic behavioral comorbidities. This study thus assessed the impact of diet sterilization in a specific pathogen-free vivarium on acute seizure presentation, the composition of the gut microbiome, and chronic behavioral comorbidities of epilepsy.

Methods

Baseline fecal samples were collected from male C57BL/6J mice (4-5 weeks-old; Jackson Labs) upon arrival. Mice were randomized to either autoclaved (AC) or irradiated (IR) diet (Prolab RMH 3000 - UU diets) or IR (Picolab 5053 - UW IR diet). Mice then underwent intracerebral TMEV or PBS injection three days later. Fecal samples were collected from a subset of mice at infection (Day 0) and Day 7 post-infection. Epilepsy-related working memory deficits and seizure threshold were assessed 6 weeks post-infection. Gut microbiome diversity was determined by 16S rRNA amplicon sequencing of fecal samples.

Results

TMEV-infected mice displayed acute handling-induced seizures, regardless of diet: 28/57 UW IR (49.1%), 30/41 UU IR (73.2%), and 47/77 UU AC (61%) mice displayed seizures. The number of observed seizures significantly differed: UW IR mice had 2.2±2.8 seizures (mean±standard deviation), UU IR mice had 3.5±2.9 seizures, and UU AC mice had 4.4±3.8 seizures during the 7-day monitoring period. The composition of the gut microbiome significantly differed in TMEV-infected mice fed the UU AC diet, with most measured differences occurring in Gram-positive bacteria. TMEV-infected mice fed the UU AC diet displayed worsened chronic working memory.

Significance

Intestinal dysbiosis evokes stark differences in acute seizure presentation in the TMEV model and vastly influences the trajectory of post-TMEV infection-induced behavioral comorbidities of epilepsy. Our study reveals a novel disease-modifying contribution of intestinal bacterial species after TMEV-induced acute seizures.

Chronic evoked seizures in young pre-symptomatic APP/PS1 mice induce serotonin changes and accelerate onset on Alzheimer's disease-related neurpathology

OBJECTIVE

People with early-onset Alzheimer's disease (AD) are at elevated seizure risk. Further, chronic seizures in pre-symptomatic stages may disrupt serotonin pathway-related protein expression, precipitating the onset of AD-related pathology and burden of neuropsychiatric comorbidities.

METHODS

2-3-month-old APP/PS1, PSEN2-N141I, and transgenic control mice were sham or corneal kindled for 2 weeks to model chronic seizures. Seizure-induced changes in glia, serotonin pathway proteins, and amyloid beta; levels in hippocampus and prefrontal cortex were quantified.

RESULTS

APP/PS1 mice experienced worsened mortality versus kindled Tg- controls. APP/PS1 females were also more susceptible to chronic kindled seizures. These changes correlated with a marked downregulation of hippocampal tryptophan hydroxylase 2 and monoamine oxidase A protein expression compared to controls; these changes were not detected in PSEN2-N141I mice. Kindled APP/PS1 mice exhibited amyloid beta; overexpression and glial overactivity without plaque deposition. PSEN2 protein expression was AD model-dependent.

SIGNIFICANCE

Seizures evoked in pre-symptomatic APP/PS1 mice promotes premature mortality in the absence of pathological amyloid deposition. Disruptions in serotonin pathway metabolism are associated with increased glial reactivity and PSEN2 downregulation without amyloid beta; deposition. This study provides the first direct evidence that seizures occurring prior to amyloid beta, plaque accumulation worsen disease burden in an AD genotype-specific manner.

Microglia specific deletion of miR-155 in Alzheimer's disease mouse models reduces amyloid-β pathology but causes hyperexcitability and seizures

Alzheimer's Disease (AD) is characterized by the accumulation of extracellular amyloid-β (Aβ) as well as CNS and systemic inflammation. Microglia, the myeloid cells resident in the CNS, use microRNAs to rapidly respond to inflammatory signals. MicroRNAs (miRNAs) modulate inflammatory responses in microglia, and miRNA profiles are altered in Alzheimer's disease (AD) patients. Expression of the pro-inflammatory miRNA, miR-155, is increased in the AD brain. However, the role of miR-155 in AD pathogenesis is not well-understood. We hypothesized that miR-155 participates in AD pathophysiology by regulating microglia internalization and degradation of Aβ. We used CX3CR1CreER/+ to drive-inducible, microglia-specific deletion of floxed miR-155 alleles in two AD mouse models. Microglia-specific inducible deletion of miR-155 in microglia increased anti-inflammatory gene expression while reducing insoluble Aβ1-42 and plaque area. Yet, microglia-specific miR-155 deletion led to early-onset hyperexcitability, recurring spontaneous seizures, and seizure-related mortality. The mechanism behind hyperexcitability involved microglia-mediated synaptic pruning as miR-155 deletion altered microglia internalization of synaptic material. These data identify miR-155 as a novel modulator of microglia Aβ internalization and synaptic pruning, influencing synaptic homeostasis in the setting of AD pathology.

Vaccine hesitancy educational tools for healthcare providers and trainees: A scoping review

In the era of vaccine hesitancy, highlighted by the current SARS-CoV2 pandemic, there is an acute need to develop an approach to reduce and address apprehension towards vaccinations. We sought to map and present an overview of existing educational interventions for healthcare providers (HCPs) on strategies to engage in effective vaccine discussion. We applied the Joanna Briggs Institute methodology framework in this scoping review. We searched five relevant databases (MEDLINE, CINAHL, EMBASE, PsycInfo, and SCOPUS) and grey literature through the Google search engine using keywords and subject headings that were systematically identified. We identified 3384 citations in peer-reviewed literature and 41 citations in grey literature. After screening for our inclusion criteria, we included 28 citations from peer reviewed literature and 16 citations from grey literature for analysis. We identified a total of 41 unique education interventions. Interventions were available from multiple disciplines, training levels, clinical settings, and diseases/vaccines. Interventions predominantly centered around two foci: knowledge sharing and communication training. Most interventions identified from peer-reviewed literature were facilitated and were applied with multiple modes of delivery. Interventions from grey literature were more topical and generally self-directed. We identified several gaps in knowledge. Firstly, accessibility and generalizability of interventions was limited. Secondly, distribution of interventions did not adequately address nursing and pharmacy disciplines, and did not cover the breadth of medical specialties for whom vaccine discussions apply. Thirdly, no interventions addressed self monitoring and the clinicians' recognition and management of emotions during difficult conversations. There is a need to address this gap and provide available, credible and comprehensive educational interventions that will support our healthcare providers in effective communication with vaccine hesitant patients.

Avasopasem manganese (GC4419) protects against cisplatin-induced chronic kidney disease: An exploratory analysis of renal metrics from a randomized phase 2b clinical trial in head and neck cancer patients

Head and neck squamous cell carcinoma (HNSCC) patients treated with high-dose cisplatin concurrently with radiotherapy (hdCis-RT) commonly suffer kidney injury leading to acute and chronic kidney disease (AKD and CKD, respectively). We conducted a retrospective analysis of renal function and kidney injury-related plasma biomarkers in a subset of HNSCC subjects receiving hdCis-RT in a double-blinded, placebo-controlled clinical trial (NCT02508389) evaluating the superoxide dismutase mimetic, avasopasem manganese (AVA), an investigational new drug. We found that 90 mg AVA treatment prevented a significant reduction in estimated glomerular filtration rate (eGFR) three months as well as six and twelve months after treatment compared to 30 mg AVA and placebo. Moreover, AVA treatment may have allowed renal repair in the first 22 days following cisplatin treatment as evidenced by an increase in epithelial growth factor (EGF), known to aid in renal recovery. An upward trend was also observed in plasma iron homeostasis proteins including total iron (Fe-blood) and iron saturation (Fe-saturation) in the 90 mg AVA group versus placebo. These data support the hypothesis that treatment with 90 mg AVA mitigates cisplatin-induced CKD by inhibiting hdCis-induced renal changes and promoting renal recovery.

Contactless skin perfusion monitoring with video cameras: tracking pharmacological vasoconstriction and vasodilation using photoplethysmographic changes

Objectives.Clinical assessment of skin perfusion informs prognosis in critically ill patients. Video camera monitoring could provide an objective, continuous method to monitor skin perfusion. In this prospective, interventional study of healthy volunteers, we tested whether video camera-derived photoplethysmography imaging and colour measurements could detect drug-induced skin perfusion changes.Approach.We monitored the lower limbs of 30 volunteers using video cameras while administering phenylephrine (a vasoconstrictor) and glyceryl trinitrate (a vasodilator). We report relative pixel intensity changes from baseline, as absolute values are sensitive to environmental factors. The primary outcome was the pre- to peak- infusion green channel amplitude change in the pulsatile PPGi waveform component. Secondary outcomes were pre-to-peak changes in the photoplethysmographic imaging waveform baseline, skin colour hue and skin colour saturation.Main results.The 30 participants had a median age of 29 years (IQR 25-34), sixteen (53%) were male. A 34.7% (p= 0.0001) mean decrease in the amplitude of the pulsatile photoplethysmographic imaging waveform occurred following phenylephrine infusion. A 30.7% (p= 0.000004) mean increase occurred following glyceryl trinitrate infusion. The photoplethysmographic imaging baseline decreased with phenylephrine by 2.1% (p= 0.000 02) and increased with glyceryl trinitrate by 0.5% (p= 0.026). Skin colour hue changed in opposite direction with phenylephrine (-0.0013,p= 0.0002) and glyceryl trinitrate (+0.0006,p= 0.019). Skin colour saturation decreased with phenylephrine by 0.0022 (p= 0.0002), with no significant change observed with glyceryl trinitrate (+0.0005,p= 0.21).Significance.Drug-induced vasoconstriction and vasodilation are associated with detectable changes in photoplethysmographic imaging waveform parameters and skin hue. Our findings suggest video cameras have great potential for continuous, contactless skin perfusion monitoring.

The impact of cultural stress and gender norms on alcohol use severity among Latino immigrant men

Alcohol misuse affects 15 million people in the United States. Compared to White men, Latino men have disproportionately higher rates of both alcohol misuse and negative alcohol-related consequences (e.g. drunk driving, liver disease, alcohol dependence, HIV/AIDS). This cross sectional study examined how cultural stressors [immigration stress and negative context of reception (NCR)] coupled with traditional Latino male gender norms (machismo and caballerismo) influences alcohol use severity (AUS) among adult Latino immigrant men. Data for the present study was collected between 2017 and 2018 from 279 Cuban, Central American, and South American adult Latino men who immigrated to the US approximately 10 years prior. Results from hierarchical multiple regression analysis revealed higher levels of perceived NCR (β = 0.15, p  = .01), and machismo (β = 0.16, p = .02) were associated with greater AUS. Significant interaction effects were found between both cultural stressors and machismo [immigration stress x machismo (β = 0.22, p < .001); NCR x machismo (β = 0.22, p < .001)] whereby higher levels of machismo strengthened the association between cultural stress and AUS. Findings from the present study can inform culturally appropriate interventions aimed at mitigating alcohol use among Latino immigrant men.

Learning from terrorist mass casualty incidents: a global survey

BACKGROUND

Reports published directly after terrorist mass casualty incidents frequently fail to capture difficulties that may have been encountered. An anonymised consensus-based platform may enable discussion and collaboration on the challenges faced. Our aim was to identify where to focus improvement for future responses.

METHODS

We conducted a mixed methods study by email of clinicians' experiences of leading during terrorist mass casualty incidents. An initial survey identified features that worked well, or failed to, during terrorist mass casualty incidents plus ongoing challenges and changes that were implemented as a result. A follow-up, quantitative survey measured agreement between responses within each of the themes using a Likert scale.

RESULTS

Thirty-three participants responded from 22 hospitals that had received casualties from a terrorist incident, representing 17 cities in low-middle, middle and high income countries. The first survey identified themes of sufficient (sometimes abundant) human resource, although coordination of staff was a challenge. Difficulties highlighted were communication, security, and management of blast injuries. The most frequently implemented changes were education on specific injuries, revising future plans and preparatory exercises. Persisting challenges were lack of time allocated to training and psychological well-being. The follow-up survey recorded highest agreement amongst correspondents on the need for re-triage at hospital (90% agreement), coordination roles (85% agreement), flexibility (100% agreement), and large-scale exercises (95% agreement).

CONCLUSION

This survey collates international experience gained from clinicians managing terrorist mass casualty incidents. The organisation of human response, rather than consumption of physical supplies, emerged as the main finding. NHSH Clinical Effectiveness Unit project registration number: 2020/21-036.

EP.WE.231Emergency Presentations of Colorectal Cancer during the COVID-19 Era

Aims

COVID-19 has reduced the ability to provide red flag investigations for colorectal patients. The aim of this study is to assess the number of emergency presentations of new colorectal malignancy during the COVID-19 era and if there is an increase in palliative cases.

Methods

A retrospective review of all patients presenting to unscheduled care with a new diagnosis of colorectal malignancy from 31st March 2020 - 25th January 2021 in a single UK Trust. An institutional data base and electronic care records were used to review patient demographics, management and curative intent. Data points for the same period in 2019-2020 were recorded for comparison.

Results

45 patients diagnosed with new colorectal malignancy during an unscheduled admission to hospital within the study timeframe. 22% (10/45) presented in January 2021. 29 diagnosed during the same time interval 2019-2020. Median age at presentation was 77.5 and 79 respectively.

40% (18/45) of patients in 2020-2021 proceeded to emergency surgery, compared to 58% (17/29) in 2019-2020 (p = 0.12).

10.3% (3/29) of 2019-2020 patients were managed with colonic stenting. This increased in 2020-2021 to 17.8% (8/45) (p = 0.38).

77.8% (35/45) patients in 2020/2021 presented at a palliative stage of disease compared to 62.1% (18/29) in 2019-2020 (p = 0.15).

Conclusions

Overall the data has not shown a statistically significant difference in patients presenting as an emergency with new colorectal malignancy. However, there was a rise in admissions noted in January 2021; should this trend continue, alongside the persistent pressures of COVID-19 ongoing research is needed to assess the true impact.

EP.WE.338Ambulatory Ultrasound Scans Reduce Inpatient Admissions During COVID-19: A Need for the Expansion of Ambulatory Services

Aim

With the increased need to manage patients out of hospital during COVID-19, it was anticipated that need for ambulatory imaging would increase. This study aimed to assess the demand for ambulatory ultrasounds (US) during the COVID-19 pandemic and the impact on inpatient admissions.

Methods

A retrospective review of patients presenting to the Emergency Department (ED) between 12^th July – 23^rd August 2020 who required an US as first line imaging. Electronic Care Records were used to collect data regarding type of US i.e., inpatient, or ambulatory, time taken for ambulatory US and outcome after imaging. The same period in 2019 was assessed for comparison.

Results

In 2020, 100 patients required an US compared to 88 in 2019. 37% (37/100) of which were discharged for an ambulatory US, compared to 14.8% (13/88) in 2019 (p = 0.006). The average waiting time for an ambulatory US in 2019 was 2 days, this increased to 7 days in 2020. Following ambulatory US in 2020 43.2% (16/37) required further outpatient imaging or assessment; similar outcomes were seen in 2019 with 46.2% (6/13). Overall, there was a 150% increase in the use of ambulatory US, with a 26% decrease in admissions in 2020 vs. 2019.

Conclusions

There was a significant increase in the number of patients discharged from ED to undergo an ambulatory US resulting in reduced inpatient admissions. This increase in demand is reflected by the prolonged waiting time highlighting the requirement for expansion of ambulatory services to meet this clinical need.

SP10.1.2 Increased Access to Computed Tomography Reduces Acute Surgical Admissions: Lessons Learnt During the COVID-19 Pandemic

Aim

With increased bed pressures due to COVID-19, keeping patients out of hospital became critical. Computed Tomography (CT) utilisation was increased to aid in the assessment of acute surgical patients. The aim of this study was to assess if increased access to CT reduced inpatient admissions.

Methods

A Retrospective audit of patients presenting to the Emergency Department (ED) between 12th July – 23rd August 2020 who required a CT scan. Data collected from Electronic Care Records and NIPACS, including patient destination at time of CT and decision following CT. For comparison, the same time-period in 2019 was assessed.

Results

In 2020, 301 patients required a CT compared to 207 in 2019. 84.7% (255/301) had a CT direct from ED in 2020 vs. 56.5% (117/207) in 2019 (p &lt; 0.001).

Of those who had CT direct from ED in 2020 18.4% (47/255) were discharged, compared to 1.7% (2/117) in 2019 (p &lt; 0.001). 9.8% (25/255) were directed to an alternative specialty in 2020 vs. 2.6% (3/117) in 2019 (p = 0.014).

2.7% (8/301) were discharged for an ambulatory CT in 2020, an increase from 0.5% (1/207) in 2019 (p = 0.07).

Overall, there was a 24% reduction in the number of patients requiring acute surgical admission in 2020 vs. 2019.

Conclusions

There was a significant increase in the number of CT’s carried out directly from ED. This enabled a significant number of patients to be discharged or transferred to a more appropriate specialty. These results demonstrate that increased access to CT can reduce the need for acute surgical admission.

A Subpopulation of Microglia Generated in the Adult Mouse Brain Originates from Prominin-1-Expressing Progenitors

Microglia maintain brain health and play important roles in disease and injury. Despite the known ability of microglia to proliferate, the precise nature of the population or populations capable of generating new microglia in the adult brain remains controversial. We identified Prominin-1 (Prom1; also known as CD133) as a putative cell surface marker of committed brain myeloid progenitor cells. We demonstrate that Prom1-expressing cells isolated from mixed cortical cultures will generate new microglia in vitro To determine whether Prom1-expressing cells generate new microglia in vivo, we used tamoxifen inducible fate mapping in male and female mice. Induction of Cre recombinase activity at 10 weeks in Prom1-expressing cells leads to the expression of TdTomato in all Prom1-expressing progenitors and newly generated daughter cells. We observed a population of new TdTomato-expressing microglia at 6 months of age that increased in size at 9 months. When microglia proliferation was induced using a transient ischemia/reperfusion paradigm, little proliferation from the Prom1-expressing progenitors was observed with the majority of new microglia derived from Prom1-negative cells. Together, these findings reveal that Prom1-expressing myeloid progenitor cells contribute to the generation of new microglia both in vitro and in vivo Furthermore, these findings demonstrate the existence of an undifferentiated myeloid progenitor population in the adult mouse brain that expresses Prom1. We conclude that Prom1-expressing myeloid progenitors contribute to new microglia genesis in the uninjured brain but not in response to ischemia/reperfusion.SIGNIFICANCE STATEMENT Microglia, the innate immune cells of the CNS, can divide to slowly generate new microglia throughout life. Newly generated microglia may influence inflammatory responses to injury or neurodegeneration. However, the origins of the new microglia in the brain have been controversial. Our research demonstrates that some newly born microglia in a healthy brain are derived from cells that express the stem cell marker Prominin-1. This is the first time Prominin-1 cells are shown to generate microglia.

The pro-inflammatory microRNA miR-155 influences fibrillar β-Amyloid1 -42 catabolism by microglia

Microglia are the innate immune cells of the central nervous system that adopt rapid functional changes in response to Damage Associated Molecular Patterns, including aggregated β-Amyloid (Aβ) found in Alzheimer's disease (AD). microRNAs (miRNAs) are post-transcriptional modulators that influence the timing and magnitude of microglia inflammatory responses by downregulating the expression of inflammatory effectors. Recent studies implicate miR-155, a miRNA known to regulate inflammatory responses, in the pathogenesis of neurodegenerative disorders including multiple sclerosis, ALS, familial Parkinson's disease, and AD. In this work, we asked if miR-155 expression in microglia modifies cellular behaviors in response to fibrillar Aβ_1-42 (fAβ_1-42 ), in vitro. We hypothesized that in microglia, miR-155 expression would impact the internalization and catabolism of extracellular fAβ_1-42 . Primary microglia stimulated with lipopolysaccharide demonstrate fast upregulation of miR-155 followed by delayed upregulation of miR-146a, an anti-inflammatory miRNA. Conditional overexpression of miR-155 in microglia resulted in significant upregulation of miR-146a. Conditional deletion of miR-155 promoted transit of fAβ_1-42 to low-pH compartments where catabolism occurs, while miR-155 overexpression decreases fAβ_1-42 catabolism. Uptake of fAβ_1-42 across the plasma membrane increased with both up and downregulation of miR-155 expression. Taken together, our results support the hypothesis that inflammatory signaling influences the ability of microglia to catabolize fAβ_1-42 through interconnected mechanisms modulated by miR-155. Understanding how miRNAs modulate the ability of microglia to catabolize fAβ_1-42 will further elucidate the role of cellular players and molecular crosstalk in AD pathophysiology.

Centralized Clinical Trial Imaging Data Management: Practical Guidance from a Comprehensive Cancer Center's Experience

Medical imaging is an integral part of clinical trial research and it must be managed properly to provide accurate data to the sponsor in a timely manner (Clune in Cancer Inform 4:33-56, 2007; Wang et al. in Proc SPIE Int Soc Opt Eng 7967, 2011). Standardized workflows for site qualification, protocol preparation, data storage, retrieval, de-identification, submission, and query resolution are paramount to achieve quality clinical trial data management such as reducing the number of imaging protocol deviations and avoiding delays in data transfer. Centralization of data management and implementation of relational databases and electronic workflows can help maintain consistency and accuracy of imaging data. This technical note aims at sharing the practical implementation of our centralized clinical trial imaging data management processes to avoid the fragmentation of tasks among various disease centers and research staff, and enable us to provide quality, accurate, and timely imaging data to clinical trial sponsors.

Ischemic preconditioning induces cortical microglial proliferation and a transcriptomic program of robust cell cycle activation

Ischemic preconditioning (IPC) is an experimental phenomenon in which a subthreshold ischemic insult applied to the brain reduces damage caused by a subsequent more severe ischemic episode. Identifying key molecular and cellular mediators of IPC will provide critical information needed to develop novel therapies for stroke. Here we report that the transcriptomic response of acutely isolated preconditioned cortical microglia is dominated by marked upregulation of genes involved in cell cycle activation and cellular proliferation. Notably, this transcriptional response occurs in the absence of cortical infarction. We employed ex vivo flow cytometry, immunofluorescent microscopy, and quantitative stereology methods on brain tissue to evaluate microglia proliferation following IPC. Using cellular colocalization of microglial (Iba1) and proliferation (Ki67 and BrdU) markers, we observed a localized increase in the number of microglia and proliferating microglia within the preconditioned hemicortex at 72, but not 24, hours post-IPC. Our quantification demonstrated that the IPC-induced increase in total microglia was due entirely to proliferation. Furthermore, microglia in the preconditioned hemisphere had altered morphology and increased soma volumes, indicative of an activated phenotype. Using transgenic mouse models with either fractalkine receptor (CX3CR1)-haploinsufficiency or systemic type I interferon signaling loss, we determined that microglial proliferation after IPC is dependent on fractalkine signaling but independent of type I interferon signaling. These findings suggest there are multiple distinct targetable signaling pathways in microglia, including CX3CR1-dependent proliferation that may be involved in IPC-mediated protection.

Stroke Volume estimation using aortic pressure measurements and aortic cross sectional area: Proof of concept

Accurate Stroke Volume (SV) monitoring is essential for patient with cardiovascular dysfunction patients. However, direct SV measurements are not clinically feasible due to the highly invasive nature of measurement devices. Current devices for indirect monitoring of SV are shown to be inaccurate during sudden hemodynamic changes. This paper presents a novel SV estimation using readily available aortic pressure measurements and aortic cross sectional area, using data from a porcine experiment where medical interventions such as fluid replacement, dobutamine infusions, and recruitment maneuvers induced SV changes in a pig with circulatory shock. Measurement of left ventricular volume, proximal aortic pressure, and descending aortic pressure waveforms were made simultaneously during the experiment. From measured data, proximal aortic pressure was separated into reservoir and excess pressures. Beat-to-beat aortic characteristic impedance values were calculated using both aortic pressure measurements and an estimate of the aortic cross sectional area. SV was estimated using the calculated aortic characteristic impedance and excess component of the proximal aorta. The median difference between directly measured SV and estimated SV was -1.4ml with 95% limit of agreement +/- 6.6ml. This method demonstrates that SV can be accurately captured beat-to-beat during sudden changes in hemodynamic state. This novel SV estimation could enable improved cardiac and circulatory treatment in the critical care environment by titrating treatment to the effect on SV.

A Randomized Controlled Study of Art Observation Training to Improve Medical Student Ophthalmology Skills

PURPOSE

Observation and description are critical to the practice of medicine, and to ophthalmology in particular. However, medical education does not provide explicit training in these areas, and medical students are often criticized for deficiencies in these skills. We sought to evaluate the effects of formal observation training in the visual arts on the general and ophthalmologic observational skills of medical students.

DESIGN

Randomized, single-masked, controlled trial.

PARTICIPANTS

Thirty-six first-year medical students, randomized 1:1 into art-training and control groups.

METHODS

Students in the art-training group were taught by professional art educators at the Philadelphia Museum of Art, during 6 custom-designed, 1.5-hour art observation sessions over a 3-month period. All subjects completed pre- and posttesting, in which they described works of art, retinal pathology images, and external photographs of eye diseases.

MAIN OUTCOME MEASURES

Grading of written descriptions for observational and descriptive abilities by reviewers using an a priori rubric and masked to group assignment and pretesting/posttesting status.

RESULTS

Observational skills, as measured by description testing, improved significantly in the training group (mean change +19.1 points) compared with the control group (mean change -13.5 points), P = 0.001. There were significant improvements in the training vs. control group for each of the test subscores. In a poststudy questionnaire, students reported applying the skills they learned in the museum in clinically meaningful ways at medical school.

CONCLUSIONS

Art observation training for first-year medical students can improve clinical ophthalmology observational skills. Principles from the field of visual arts, which is reputed to excel in teaching observation and descriptive abilities, can be successfully applied to medical training. Further studies can examine the impact of such training on clinical care.

A comparison between four techniques to measure cardiac output

Cardiac output is an important variable when monitoring hemodynamic status. In particular, changes in cardiac output represent the goal of several circulatory management therapies. Unfortunately, cardiac output is very difficult to estimate, either in experimental or clinical settings. The goal of this work is to compare four techniques to measure cardiac output: pressure-volume catheter, aortic flow probe, thermodilution, and the PiCCO monitor. These four techniques were simultaneously used during experiments of fluid and endotoxin administration on 7 pigs. Findings show that, first, each individual technique is precise, with a relative coefficient of repeatability lower than 7 %. Second, 1 cardiac output estimate provided by any technique relates poorly to the estimates from the other 3, even if there is only small bias between the techniques. Third, changes in cardiac output detected by one technique are only detected by the others in 62 to 100 % of cases. This study confirms the difficulty of obtaining a reliable clinical cardiac output measurement. Therefore, several measurements using different techniques should be performed, if possible, and all such should be treated with caution.

Challenges in the development of chronic pulmonary hypertension models in large animals

Pulmonary hypertension (PH) results in significant morbidity and mortality. Chronic PH animal models may advance the study of PH's mechanisms, evolution, and therapy. In this report, we describe the challenges and successes in developing three models of chronic PH in large animals: two models (one canine and one swine) utilized repeated infusions of ceramic microspheres into the pulmonary vascular bed, and the third model employed a surgical aorto-pulmonary shunt. In the canine model, seven dogs underwent microsphere infusions that resulted in progressive elevation of pulmonary arterial pressure over a few months. In this model, pulmonary endoarterial tissue was obtained for histology. In the aorto-pulmonary shunt swine model, 17 pigs developed systemic level pulmonary pressures after 2-3 months. In this model, pulmonary endoarterial tissue was sequentially obtained to assess for changes in gene and microRNA expression. In the swine microsphere infusion model, three pigs developed only a modest chronic increase in pulmonary arterial pressure, despite repeated infusions of microspheres (up to 40 in one animal). The main purpose of this model was for vasodilator testing, which was performed successfully immediately after acute microsphere infusions. Chronic PH in large animal models can be successfully created; however, a model's characteristics need to match the investigational goals.

Effect of internal versus external focus of attention on implicit motor learning in children with developmental coordination disorder

Children with developmental coordination disorder (DCD) struggle to learn new motor skills. It is unknown whether children with DCD learn motor skills more effectively with an external focus of attention (focusing on impact of movement on the environment) or an internal focus of attention (focusing on one's body movements) during implicit (unconscious) and explicit (conscious) motor learning.

PURPOSE

This paper aims to determine the trends of implicit motor learning in children with DCD, and how focus of attention influences motor learning in children with DCD in comparison with typically developing children.

METHODS

25 children, aged 8-12, with (n=12) and without (n=13) DCD were randomly assigned to receive instructions that focused attention externally or internally while completing a computer tracking task during acquisition, retention, and transfer phases. The motor task involved tracking both repeated and random patterns, with the repeated pattern indicative of implicit learning.

RESULTS

Children with DCD scored lower on the motor task in all three phases of the study, demonstrating poorer implicit learning. Furthermore, graphical data showed that for the children with DCD, there was no apparent difference between internal and external focus of attention during retention and transfer, while there was an advantage to the external focus of attention group for typically developing children.

CONCLUSION

Children with DCD demonstrate less accuracy than typically developing children in learning a motor task. Also, the effect of focus of attention on motor performance is different in children with DCD versus their typically developing counterparts during the three phases of motor learning.

IMPLICATIONS

Results may inform clinicians how to facilitate motor learning in children with DCD by incorporating explicit learning with either internal or external focus of attention within interventions.