Duty-related trauma and PTSD symptoms in US urban firefighters

BACKGROUND

Little is known about the multi-dimensional nature of traumatic duty-related events encountered by firefighters in relation to their post-traumatic stress disorder (PTSD) risk.

AIMS

To describe the types of duty-related events encountered by career firefighters and explore if years in the fire service or total event load moderated the association of trauma exposure to PTSD symptoms.

METHODS

Participants included 755 career, male firefighters (19% of the department's firefighters and 76% of those who accessed the electronic anonymous survey). The Duty-Related Incident Stressors scale was used to assess exposure to 25 potentially traumatic events (event load) and self-appraisal of the stress associated with these events, grouped by type of event (indirect, direct and colleague-related). The Post-Traumatic Stress Disorder Checklist was used to assess PTSD symptoms.

RESULTS

Firefighters rated colleague-related events as the most stressful, followed by indirect and direct events. Event load (r = 0.25) and indirect, direct and colleague-related events stress (r = 0.32-0.35) were positively associated with PTSD symptoms. Results of moderation analyses indicated that event load served as a risk factor in the relation of indirect events stress to PTSD symptoms, and as a buffer in the relation of direct events stress to PTSD symptoms. Years in the fire service were not associated with PTSD symptoms nor moderated the relation of event stress to PTSD symptoms.

CONCLUSIONS

Findings underscored the importance of considering the differential effects that types of duty-related traumatic events and cumulative exposure to trauma may have on firefighters' PTSD symptoms.

Oral histories document community mobilisation to participate in decision-making regarding a hazardous waste thermal treatment facility

Colfax, Louisiana hosts a commercial hazardous waste thermal treatment (TT) facility, which treats fireworks, explosives, and military ordnances by open-burn/open-detonation one mile from the edge of the nearest community. Seventy-one percent of Colfax's residents are Black, and forty-six percent live below poverty, indicating the community's structural vulnerability. This community-based study originated at the behest of Colfax community members. We hypothesized that the close relationships among members of this enclave may have enhanced the community's ability to mobilize in opposition to the TT facility. We conducted semi-structured oral history interviews with nineteen community members and examined the social and interorganizational networks used by the Colfax community to claim its role in decision-making regarding the TT facility after years of exclusion from this process. Interview transcripts were analyzed through the lens of community capacity theory to gain insight into how interactions among community members about the environmental hazards led to social mobilization and improved participation in the decision-making process using codes for communication, organization, and outcome. Additionally, we reviewed Louisiana Department of Environmental Quality records for complaints about the facility to gauge public participation. One notable theme across several interviews was exclusion from the initial decision-making process related to the facility. However, interviewees noted a sustained effort was made among community members to educate themselves about the facility, organize a response through neighbor-to-neighbor contact, and take action by submitting formal complaints and participating in public hearings. Through the lens of environmental justice, this study illustrates an evolving condition of procedural justice.

Aloe Vera Extract Gel-Biosynthesized Selenium Nanoparticles Enhance Disease Resistance in Lettuce by Modulating the Metabolite Profile and Bacterial Endophytes Composition

The use of nanotechnology to suppress crop diseases has attracted significant attention in agriculture. The present study investigated the antifungal mechanism by which aloe vera extract gel-biosynthesized (AVGE) selenium nanoparticles (Se NPs) suppressed Fusarium-induced wilt disease in lettuce (Lactuca sativa). AVGE Se NPs were synthesized by utilizing sodium selenite as a Se source and AVGE as a biocompatible capping and reducing agent. Over 21 d, 2.75% of total AVGE Se NPs was dissolved into Se ions, which was more than 8-fold greater than that of bare Se NPs (0.34%). Upon exposure to soil applied AVGE Se NPs at 50 mg/kg, fresh shoot biomass was significantly increased by 61.6 and 27.8% over the infected control and bare Se NPs, respectively. As compared to the infected control, the shoot levels of citrate, isocitrate, succinate, malate, and 2-oxo-glutarate were significantly upregulated by 0.5-3-fold as affected by both Se NPs. In addition, AVGE Se NPs significantly increased the shoot level of khelmarin D, a type of coumarin, by 4.40- and 0.71-fold over infected controls and bare Se NPs, respectively. Additionally, AVGE Se NPs showed greater upregulation of jasmonic acid and downregulation of abscisic acid content relative to bare Se NPs in diseased shoots. Moreover, the diversity of bacterial endophytes was significantly increased by AVGE Se NPs, with the values of Shannon index 40.2 and 9.16% greater over the infected control and bare Se NPs. Collectively, these findings highlight the significant potential of AVGE Se NPs as an effective and biocompatible strategy for nanoenabled sustainable crop protection.

Abstract TP224: Comparing Utility Of Computed Tomography Angiography Of Neck Vs Transesophageal Echocardiography For Detection Of Aortic Plaque

Background: Aortic arch atherosclerotic plaques of >4mm thickness, evaluated by a transesophageal echocardiogram (TEE) correlate with embolic ischemic stroke. Computed tomography angiography (CTA) of the neck, routinely done during stroke evaluation, is an alternative for the evaluation of aortic arch plaque. We hypothesized that CTA evaluation of the aortic arch plaque is comparable to TEE.

Methods: We prospectively measured thickness, extent through different parts of the aortic arch (ascending, arch, and descending aorta), location of the maximal plaque thickness, calcification, mobility, and presence of thrombus in the aortic arch plaque on CTA neck and TEE exams in non-consecutive stroke patients from the hospital database. All measurements were done independently by 2 radiologists for the CTA of neck and 2 cardiologists for TEE. Paired t-test was used for mean difference and Wilcoxon signed-rank test for median difference between TEE and CTA.

Results: Of 63 patients who had both CTA and TEE, 31 (mean age ± SD; 54 ± 14.46 years) were included in this analysis; as in 32 patients, aortic arch was not included on the CTA neck. Although maximal plaque thickness was comparable for both methods (CTA 3.0 ± 1.10 vs TEE 3.18 ± 2.54, p=0.68), CTA more commonly showed the extent of the plaque throughout all areas (ascending, arch, and descending) of the aorta (CTA: 25/31 vs TEE: 15/31, p<0.01), thickest plaque on the stroke embologenic (ascending and arch) location (CTA: 15/31 vs TEE: 6/31, p<0.01), and identified calcified plaque components (CTA: 26/31 vs TEE: 15/31, p<0.01). In addition, CTA exhibited branching patterns of the aorta, while TEE was beneficial to detect mobile plaque debris (8/31) and thrombi (TEE: 1/31 vs CTA: 0/31, p=1.0).

Conclusion: Both CTA and TEE are useful for aortic arch evaluation in stroke patients, contributing different information. Future investigations in a larger prospective cohort are warranted.

Examining the efficacy of vibrotactile displays for monitoring patient vital signs: Six laboratory studies of change detection and state identification

Healthcare workers often monitor patients while moving between different locations and tasks, and away from conventional monitoring displays. Vibrotactile displays can provide patient information in vibrotactile patterns that are felt regardless of the worker's location. We examined how effectively participants could identify changes in vibrotactile representations of patient heart rate (HR) and oxygen saturation (SpO₂). In Experiment 1, participants identified changes in HR and SpO₂ with greater than 90% accuracy while using vibrotactile displays configured in either an integrated or a separated format. In Experiment 2, incidental auditory and visual cues were removed and performance was still greater than 90% for the integrated display. In Experiments 3 and 4, ongoing tasks with low or high task load were introduced; high load worsened participants' response accuracy and speed at identifying vital signs. In Experiments 5 and 6, alternative designs were tested, including a design with a seemingly more natural mapping of HR to vibrotactile stimulation. However, no design supported more accurate performance than the integrated display. Results are interpreted with respect to multiple resource theory, and constraints on conforming to design guidelines are noted. Vibrotactile displays appear to be viable and therefore potentially suitable for use in healthcare and other contexts. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Cardiometabolic disease, comorbidities and risk of death: findings using data from large-scale electronic health records

Background

Myocardial infarction (MI), stroke and diabetes are separately associated with increased risk of mortality but it is uncertain if their combined effects are proportional, amplified or less than the expected risk of each disease individually. In addition, patients with these conditions tend to also have other long-term comorbidities. How the relationship between cardiometabolic disease and risk of death is modified by the presence of comorbidity is unclear.

Purpose

We investigated the separate and combined effects of MI, stroke and diabetes on all-cause mortality, and examined the impact of comorbidity on these associations.

Methods

We selected a patient cohort of 2,007,731 (51% women) aged ≥16 years at registration with their general practice, using large-scale UK primary care electronic health records that were linked to the national death registry. We identified patients with a recorded diagnosis of MI, stroke, diabetes or none before 2005 (baseline), and classified the patient cohort into mutually exclusive categories of their baseline disease status. For each group, we also extracted information on another major 53 long-term conditions prior to baseline. The cohort was followed until death, deregistration from the practice or censored at the end of study (31 Dec 2014). We used Cox regression, and tested for departure from additivity and multiplicativity to assess interaction.

Results

At baseline, the mean age of the cohort was 51 (SD=18) years and 7% (N=145,910) had a cardiometabolic disease. Over an average follow-up of 7 (SD=3) years, 270,036 died (mean age of death=79 years). After adjusting for baseline age and sex, the hazard ratio (HR) (95% confidence interval [CI]), relative to those without cardiometabolic disease, were as follows: diabetes=1.53 (1.51 to 1.55), MI=1.54 (1.51 to 1.56), stroke=1.87 (1.84 to 1.90), diabetes and MI=2.16 (2.09 to 2.23), MI and stroke=2.39 (2.28 to 2.49), diabetes and stroke=2.56 (2.47 to 2.65), and all three=3.17 (2.95 to 3.41). After adjusting for the 53 comorbidities, the HR (95% CI) were attenuated: diabetes=1.37 (1.35 to 1.39), MI=1.25 (1.23 to 1.27), stroke=1.49 (1.46 to 1.52), diabetes and MI=1.60 (1.55 to 1.65), MI and stroke=1.52 (1.45 to 1.59), diabetes and stroke=1.91 (1.84 to 1.98), and all three=1.77 (1.64 to 1.91). The results did not materially changed with adjustment for smoking and deprivation level. Test for interaction revealed some minor synergistic effects when cardiometabolic disease co-occurred but excess risks were lower than expected for two combined vs individual disease effects; no significant interaction was seen for all three vs individual disease effects.

Conclusion

MI, stroke and diabetes are associated with excess mortality, which was partly due to associated chronic conditions. We found no evidence that the co-occurrence of these three conditions contribute to a higher excess mortality than expected from each of them separately.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): NIHR Oxford Biomedical Research Centre; Oxford Martin School, University of Oxford

Association between comorbidities and blood pressure trajectories in patients with hypertension

Background

Our knowledge of how to better manage elevated blood pressure in presence of comorbidities is limited; in part due to exclusion or underrepresentation of multimorbid patients from major clinical trials.

Purpose

To investigate the burden and types of comorbidities in patients with hypertension, to assess how such comorbidities and other variables affect blood pressure levels over time.

Methods

The study was conducted using linked electronic health records from the UK Clinical Practice Research Datalink study from its inception on 1 January 1985 to 30 September 2015. Using linked electronic health records, we compared systolic blood pressure levels among 295,487 patients with diagnosed hypertension by type and numbers of major comorbidities from at least 5 years before to up to 10 years after hypertension diagnosis. We used a multiple landmark cohort design in order to investigate associations prospectively with time-updated information that takes advantage of the dynamic nature of electronic health records.

Results

Time-updated multivariable linear regression analyses showed that the presence of more comorbidities was independently associated with lower blood pressure during follow-up. This negative association was not specific to particular types of comorbidities; although associations were stronger in those with pre-existing cardiovascular disease. Tracking patients backwards to years prior to hypertension diagnosis revealed that the association between comorbidities and blood pressure were even more pronounced in years before hypertension diagnosis. Despite substantial declines in blood pressure in the first year after diagnosis, subsequent changes were modest, with no evidence of a more rapid decline in those with more or specific types of comorbidities.

Conclusions

Blood pressure levels at which patients were diagnosed with hypertension varied substantially and were lower when patients had more comorbidities. This early selection bias was a key determinant of long-term differences in blood pressure by comorbidity status and provides an additional explanation for the lower blood pressure in multimorbid patients.

Mean SBP (mmHg) over time

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): National Institute for Health Research Oxford Biomedical Research Centre, Rhodes Trust and Clarendon Fund

Association between traumatic brain injuries and ketamine infusion side effects following combat injury

INTRODUCTION

Ketamine is a vital component for acute pain management in emergency trauma care for both civilian and military hospitals. This preliminary analysis examined whether combat-injured US service members sustaining traumatic brain injuries (TBI) experienced increased odds of ketamine side effects compared with those without TBI.

METHODS

This preliminary analysis included combat-injured service members, ages ≥18 years with documented pain scores during the 24 hours before and 48 hours after receiving an intravenous ketamine infusion at Walter Reed National Military Medical Center (WRNMMC) between 2007 and 2014. Logistic regression modeling examined the association between TBI and ketamine side effects (eg, hallucinations, nightmares, dysphoria, nausea, decreased oxygen saturation) during hospitalisation.

RESULTS

Of the 77 patients, 62% presented with a documented TBI. Side effects were documented for 18.8% of those without TBI and 24.4% of those with TBI. Analyses were unable to find evidence against the null hypothesis with the current sample size, even when adjusting for injury characteristics and preinfusion opioid doses (adjusted OR=0.90 (95% CI 0.26 to 3.34), p=0.87).

CONCLUSION

In this small sample of combat-injured service members, we were unable to detect a difference in ketamine-related side effects by documented TBI status. These hypothesis-generating findings support the need for future studies to examine the use of intravenous ketamine infusions for pain management, and subsequent care outcomes in patients who experience polytraumatic trauma inclusive of TBI.

PTSD symptoms and suicidal ideation in US female firefighters

BACKGROUND

Little is known regarding the mental health of women firefighters.

AIMS

To identify demographic, work-related and mental health characteristics associated with post-traumatic stress disorder (PTSD) symptoms and lifetime suicidal ideation in female firefighters compared with male colleagues.

METHODS

Participants were firefighters (75 women and 2564 men) employed in a large urban fire department in the USA. Chi-square, correlations, t-tests and analyses of variance were conducted to examine the predictors of PTSD symptoms and lifetime suicide ideation in men and women.

RESULTS

Approximately 20% of women scored positively for PTSD and 30% reported lifetime suicidal ideation. Women with PTSD symptoms were more likely to be in their mid-career years (11-20) than in their first 10 years (87% versus 44%; χ2 = 8.77, P < 0.05) and to have received counselling (53% versus 14%; χ2 = 8.11, P < 0.01). Being single (73% versus 58%; χ2 = 6.02, P < 0.05), having a second job (68% versus 38%; χ2 = 5.79, P < 0.05) and having received counselling (41% versus 11%; χ2 = 8.51, P < 0.01) predicted suicide ideation. Depression and general stress positively predicted PTSD symptoms and suicide ideation. PTSD also predicted suicide ideation.

CONCLUSIONS

Compared to male firefighters, women were at high risk for PTSD symptoms and suicide ideation. Particularly for women, few socio-demographic and work-related variables were associated with these outcomes. Mental health variables predicted depression and suicide ideation for both gender groups. Therefore, in screening and intervention efforts, it may be most fruitful to focus on mental health risk correlates of PTSD and suicide ideation.

P1548Long-term past, current and usual systolic blood pressure and incident cardiovascular disease: risk prediction using large-scale, routinely recorded clinical data

Background

The impact of long-term exposure to elevated systolic blood pressure (SBP) on future cardiovascular disease (CVD) in “real-world” settings, and its relevance to risk prediction, are less investigated.

Purpose

To examine the risk of incident CVD in relation to long-term past, current, and usual SBP, and compare their predictive performance, using evidence from large-scale electronic health records (EHR).

Methods

Using data extracted from UK primary care linked EHR, we applied a landmark cohort study design, by including patients aged 40 (N≈64,000), 50 (N≈80,000) and 60 (N≈67,000) years (y) at study entry who had recorded SBP and with no prior CVD or previous antihypertensive or lipid-lowering prescriptions at baseline. We estimated past SBP (mean, time-weighted mean, and variability recorded up to 10 years prior to baseline) and usual SBP (correcting current values for past time-dependent SBP variability). We used Cox regression to estimate hazard ratio (HR), and applied Bayesian analysis within a machine learning framework in developing and validating models. To evaluate predictive performance of the models, we used discrimination (area under the curve [AUC]) and calibration metrics. The outcome was incident CVD (first hospitalisation for or death from coronary heart disease or stroke/transient ischaemic attack). Analyses were conducted separately for each age cohort.

Results

After a mean follow-up of 8 years, the numbers of patients who developed incident CVD were over 1000 (40y), 3000 (50y) and 5000 (60y). Higher past, current and usual SBP values were separately and independently associated with increased incident CVD risk. Per 20-mmHg rise in SBP, the HR (95% credible interval [CI]) for current SBP for ages 40, 50 and 60 years were 1.18 (1.08 to 1.26), 1.22 (1.18 to 1.30) and 1.22 (1.19 to 1.24); the corresponding HR were stronger in magnitude for past SBP (mean and time-weighted mean) and usual SBP (HR ranged from: 40y=1.31 to 1.41, 50y=1.39 to 1.45 and 60y=1.32 to 1.48). For each age cohort, the AUC (95% CI) for the model that included current SBP, sex, smoking, deprivation, diabetes and lipid profile in the validation sample were: 40y=0.739 (0.730 to 0.746), 50y=0.750 (0.716 to 0.810), and 60y=0.647 (0.642 to 0.658). Adding past SBP mean, time-weighted mean or variability to this model were associated with modest increases in the AUC and all models showed good calibration. Small improvements in the AUC were similarly observed when evaluating models separately for men and women within each age cohort.

Conclusion

Using multiple SBP recordings from patients' EHR showed stronger associations with incident CVD than a single SBP measurement, but their addition to multivariate risk prediction models had negligible effects on model performance.

Acknowledgement/Funding

Oxford Martin School and National Institute for Health Research Oxford Biomedical Research Centre

Oral health behaviours of older Australian men: the Concord Health and Ageing in Men Project

BACKGROUND

The Concord Health and Ageing in Men Project (CHAMP) is a cohort study of the health of a representative sample of older Australian men. The aim of this paper is to describe the oral health behaviours and dental service use of CHAMP participants and explore associations between oral health behaviours with and general health status.

METHOD

Information collected related to socio-demographics, general health, oral health service-use and oral health behaviours. Key general health conditions were ascertained from the health questionnaire and included physical capacity and cognitive status.

RESULTS

Fifty-seven percent of the men reported visiting a dental provider at least once or more a year and 56.7% did so for a "dental check-up". Of those with some natural teeth, 59.3% claimed to brush their teeth at least twice or more a day. Most men (96%) used a standard fluoride toothpaste. Few participants used dental floss, tooth picks or mouth-rinses to supplement oral hygiene. Cognitive status and self-rated general health were associated with dental visiting patterns and toothbrushing behaviour.

CONCLUSIONS

Most older men in CHAMP perform favourable oral health behaviours. Smoking behaviour is associated with less favourable dental visiting patterns, and cognitive status with toothbrushing behaviour.

Polyomaviruses of the skin: integrating molecular and clinical advances in an emerging class of viruses

BACKGROUND

Human polyomaviruses (HPyVs) are small, nonenveloped, double-stranded DNA viruses that express tumour antigen proteins. Fourteen species of polyomaviruses have been discovered in humans, and since the 2008 discovery of the first cutaneous polyomavirus - Merkel cell polyomavirus (MCPyV) - six more species have been detected in the skin: trichodysplasia spinulosa-associated polyomavirus (TSPyV), HPyV6, HPyV7, HPyV9, HPyV10 and HPyV13. Of these cutaneous species, only MCPyV, TSPyV, HPyV6 and HPyV7 have been definitively associated with diseases of the skin, most commonly in immunocompromised individuals. MCPyV is a predominant aetiology in Merkel cell carcinomas. TSPyV is one of the aetiological factors of trichodysplasia spinulosa. HPyV6 and HPyV7 have been recently linked to pruritic skin eruptions. The roles of HPyV9, HPyV10 and HPyV13 in pathogenesis, if any, are still unknown, but their molecular features have provided some insight into their functional biology.

RESULTS

In this review, we summarize the known molecular mechanisms, clinical presentation and targeted therapies of each of the eight cutaneous HPyVs.

CONCLUSIONS

We hope that heightened awareness and clinical recognition of HPyVs will lead to increased reports of HPyV-associated diseases and, consequently, a more robust understanding of how to diagnose and treat these conditions.

Tactile Displays of Pulse Oximetry

Prior investigations of vibrotactile displays suggest they have promise for use in the healthcare domain. This exploratory study forms part of a series exploring the use of an upper arm, continuously informing, vibrotactile display of pulse oximetry for clinicians. The study focused on the effect of vigilance on participants’ accuracy and latency for detecting and identifying changes in vital sign levels. Twenty-one participants were tested in a within-subjects design in four blocks of approximately 18 minutes duration each. Two blocks were a low workload condition and the other two blocks a high workload condition. Data were analysed against thresholds of 90% for accuracy and 10 seconds for response latency and workload conditions were also compared for accuracy and latency. Participants’ accuracy was not better than 90% and response latency was not shorter than 10 seconds, even in the low workload conditions. Participants were slower to detect changes in the high workload condition, and detection time worsened as the experiment progressed. Taken together, the results suggest that detecting rare events places a high strain on cognition and negatively affects performance. These findings have implications for the use of vibrotactile displays and will guide further investigations into the use of vibrotactile technology in healthcare.

All-ceramic crown preparations: An alternative technique

BACKGROUND

The aim of this study was to compare the crown preparation dimensions produced from two different techniques of preparation for posterior all-ceramic crowns.

METHODS

Twenty-four fourth year dental students undertook a course of advanced simulation training involving education in an alternative technique of preparation for a 36 all-ceramic crown. Crown preparations performed using the traditional technique were compared with an alternative technique for total occlusal convergence (TOC) and reduction difference (RD) using digital scanning and comparative software.

RESULTS

Groups that spent the most time performing the alternative technique produced crown preparations with significantly lower buccolingual (BL) TOC. The training resulted in crown preparations that were closer to ideal TOC and RD measurements.

CONCLUSIONS

The alternative technique of crown preparation for a posterior all-ceramic crown showed initial promise in creating a less buccolingually tapered and more ideally occlusally reduced crown preparation.

Structure-based design of 3-carboxy-substituted 1,2,3,4-tetrahydroquinolines as inhibitors of myeloid cell leukemia-1 (Mcl-1)

A novel Mcl-1 inhibitor chemotype based on a tetrahydroquinoline carboxylic acid was developed utilizing structure-based design, which was subsequently validated by a fluorescence polarization competition assay and HSQC NMR analysis.

Covalent Chemical Ligation Strategy for Mono- and Polyclonal Immunoglobulins at Their Nucleotide Binding Sites

Nonspecific ligation methods have been traditionally used to chemically modify immunoglobulins. Site-specific ligation of compounds (toxins or ligands) to antibodies has become increasingly important in the fields of therapeutic antibody-drug conjugates and bispecific antibodies. In this present study, we took advantage of the reported nucleotide-binding pocket (NBP) in the Fab arms of immunoglobulins by developing indole-based, 5-fluoro-2,4-dinitrobenzene-derivatized OBOC peptide libraries for the identification of affinity elements that can be used as site-specific derivatization agents against both mono- and polyclonal antibodies. Ligation can occur at any one of the few lysine residues located at the NBP. Immunoconjugates resulting from such affinity elements can be used as therapeutics against cancer or infectious agents.

Prevalence and severity of asthmatic symptoms in Grenadian school children: the Grenada National Asthma Survey

OBJECTIVE

The goal of this study was to determine the prevalence of asthma in school children in the tri-island Caribbean nation of Grenada.

SETTING, PARTICIPANTS AND OUTCOMES

This was a self-report study provided to the guardians of all primary school children between ages 6 and 7 throughout Grenada, Carriacou and Petite Martinique in 2013. Of the 2362 surveys provided, 1374 were returned, resulting in a response rate of 58.2%. Only responders listing birthdays between 1 January 2006 and 31 December 2007 were included in the analysis, resulting in 1165 qualifying responders. Asthma diagnosis was based on previous physician diagnosed asthma and/or self-reported presence of wheeze in the past 12 months (current wheeze). Severity of asthma, medication usage, environmental exposures, physician and emergency department visits were compared among respondents.

RESULTS

The prevalence of wheezing in the past year was 30.5±1.8%, and of these 68.4% were previously diagnosed with asthma. Of the current wheeze participants, 39.9±9.2% reported moderate to severe asthma symptoms and increased exposure to cigarette smoke, excessive dust, burning brush and landfills. Carriacou and Petite Martinique, the two smaller islands, had a lower incidence of current wheeze (14.1±7.7%) and exposure rates to cigarette smoke and burning brush as compared to the larger, denser island of Grenada. Although 65.7% of respondents diagnosed with asthma reported taking medication, the number of annual doctor and emergency department visits were high (2.82 and 0.86, respectively). Respondents with the most severe asthma symptoms reported the most emergency department visits with an average of 1.05 visits annually, whereas respondents with moderate asthma symptoms had the most doctor visits with an average of 3.33 visits annually.

CONCLUSIONS

This study indicates that the prevalence of childhood asthma in Grenada is very high and warrants policy consideration in public health and education to decrease its morbidity.

Tactile Displays of Pulse Oximetry in Integrated and Separated Configurations

Vibrotactile displays have been trialled in a variety of cognitively demanding domains, including healthcare. Previous work suggests that vibrotactile displays can be used to inform clinicians of patient status, particularly when the displays are alarm-style alerts in surgical or critical care. The goal of the present study is to evaluate how well a common measure of patient well-being—pulse oximetry—can be communicated via an upper-arm vibrotactile prototype. Pulse oximetry includes two important vital signs: heart rate and oxygen saturation. Two displays were tested in a between-subjects design: (1) the Separated display presented heart rate first, followed by oxygen saturation; and (2) the Integrated display communicated both vital signs simultaneously. Participants identified five ranges of heart rate and three levels of oxygen saturation with very high accuracy (>90%), regardless of display type. Although participants’ identification accuracy improved marginally with practice, their initial high level of performance was achieved with minimal training. Findings will inform a broader program of research in which we aim to test whether vibrotactile displays might be useful as a part of multi-modal patient monitoring.

Bupivacaine-induced cellular entry of QX-314 and its contribution to differential nerve block

BACKGROUND AND PURPOSE

Selective nociceptor fibre block is achieved by introducing the cell membrane impermeant sodium channel blocker lidocaine N-ethyl bromide (QX-314) through transient receptor potential V1 (TRPV1) channels into nociceptors. We screened local anaesthetics for their capacity to activate TRP channels, and characterized the nerve block obtained by combination with QX-314.

EXPERIMENTAL APPROACH

We investigated TRP channel activation in dorsal root ganglion (DRG) neurons by calcium imaging and patch-clamp recordings, and cellular QX-314 uptake by MS. To characterize nerve block, compound action potential (CAP) recordings from isolated nerves and behavioural responses were analysed.

KEY RESULTS

Of the 12 compounds tested, bupivacaine was the most potent activator of ruthenium red-sensitive calcium entry in DRG neurons and activated heterologously expressed TRPA1 channels. QX-314 permeated through TRPA1 channels and accumulated intracellularly after activation of these channels. Upon sciatic injections, QX-314 markedly prolonged bupivacaine's nociceptive block and also extended (to a lesser degree) its motor block. Bupivacaine's blockade of C-, but not A-fibre, CAPs in sciatic nerves was extended by co-application of QX-314. Surprisingly, however, this action was the same in wild-type, TRPA1-knockout and TRPV1/TRPA1-double knockout mice, suggesting a TRP-channel independent entry pathway. Consistent with this, high doses of bupivacaine promoted a non-selective, cellular uptake of QX-314.

CONCLUSIONS AND IMPLICATIONS

Bupivacaine, combined with QX-314, produced a long-lasting sensory nerve block. This did not require QX-314 permeation through TRPA1, although bupivacaine activated these channels. Regardless of entry pathway, the greatly extended duration of block produced by QX-314 and bupivacaine may be clinically useful.

SHP-1 phosphatase is a critical regulator in preventing natural killer cell self-killing

Balance of signals generated from the engaged activating and inhibitory surface receptors regulates mature NK cell activities. The inhibitory receptors signal through immunoreceptor tyrosine based inhibitory motifs (ITIM), and recruit phosphatases such as SHP-1 to inhibit NK cell activation. To directly examine the importance of SHP-1 in regulating activities and cell fate of mature NK cells, we used our established lentiviral-based engineering protocol to knock down the SHP-1 protein expression in primary C57BL/6NCrl cells. Gene silencing of the SHP-1 in primary NK cells abrogated the ability of ITIM-containing NK inhibitory receptors to suppress the activation signals induced by NK1.1 activating receptors. We followed the fates of stably transduced SHP-1 silenced primary NK cells over a longer period of time in IL-2 containing cultures. We observed an impaired IL-2 induced proliferation in the SHP-1 knockdown NK cells. More interestingly, these "de-regulated" SHP-1 knockdown NK cells mediated specific self-killing in a real-time live cell microscopic imaging system we developed to study NK cell cytotoxicity in vitro. Selective target recognition of the SHP-1 knockdown NK cells revealed also possible involvement of the SHP-1 phosphatase in regulating other NK functions in mature NK cells.