Does celecoxib prescription for pain management impact post-tonsillectomy hemorrhage requiring surgery? A retrospective observational cohort study

BACKGROUND

Adenotonsillectomy and tonsillectomy (now referred to as tonsillectomy thereafter) are common pediatric surgeries. Postoperative complications include hemorrhage requiring surgery (2-3% of cases) and pain. While non-steroidal anti-inflammatory drugs are commonly administered for post-surgical pain, controversy exists regarding bleeding risk with cyclo-oxygenase-1 inhibition and associated platelet dysfunction. Preliminary evidence suggests selective cyclo-oxygenase-2 inhibitors, for example celecoxib, effectively manage pain without adverse events including bleeding. Given the paucity of data for routine celecoxib use after tonsillectomy, we investigated the association between post-operative celecoxib prescription and post-tonsillectomy hemorrhage requiring surgery using chart-review data from the Children's Hospital of Eastern Ontario, Canada.

METHODS

After ethics approval we performed a retrospective single-center observational cohort study in children <18 yrs undergoing tonsillectomy from January 2007 to December 2017. Cases of adenoidectomy alone were excluded due to low bleed rates. The primary outcome was the proportion of patients with post-tonsillectomy hemorrhage requiring surgery. The association between a celecoxib prescription and post-tonsillectomy hemorrhage requiring surgery was estimated using inverse probability of treatment weighting based on propensity scores and using generalized estimating equations to accommodate clustering by surgeon.

RESULTS

An initial patient cohort of 6468 was identified and 5846 children with complete data were included in analyses. Median (interquartile range) age was 6.10 (4.40, 9.00) years and 46% were female. In our cohort, 28.1% (n=1644) were prescribed celecoxib. Among the 4996 tonsillectomy patients, 1.7% (n=86) experienced post-tonsillectomy hemorrhage requiring surgery. The proportion with post-tonsillectomy hemorrhage requiring surgery among patients who had a tonsillectomy and were or were not prescribed celecoxib was 1.94% (30/1548; 95% CI: 1.36-2.75) and 1.62% (56/3448; 95% CI: 1.25-2.10), respectively. Modelling did not identify an association between celecoxib prescription and increased odds of post-tonsillectomy hemorrhage requiring surgery (OR=1.4, 95% CI: 0.85-2.31, p=0.20).

CONCLUSIONS

Celecoxib does not significantly increase the odds of post-tonsillectomy hemorrhage requiring surgery, after adjusting for covariates. This large pediatric cohort study of celecoxib administered after tonsillectomy provides compelling evidence for safety but requires confirmation with a multi-site randomized controlled trial.

Hand hygiene knowledge and practices of family caregivers in inpatient pediatrics

Family caregivers are essential inpatient pediatric care partners, yet their handwashing knowledge and compliance are rarely studied. Through hand hygiene audits and self-administered questionnaires, we observed 9% compliance, significantly lower than self-reported practice. We suggest interventions to improve caregiver handwashing behaviors to decrease infection transmission risk to hospitalized children.

A climate resilience maturity matrix for Canadian health systems

Healthcare decision-makers are becoming increasingly aware that climate change poses significant threats to population health and continued delivery of quality care. Challengingly, responding to climate change requires complex, often expensive, and multi-faceted actions to limit new emissions from worsening climate trajectories, while investing in climate-resilient systems. We present a Climate Resilience Maturity Matrix that brings together both mitigation and adaptation actions into a high-level tool for health leaders, for supporting organizational review, assessment, and decision-making for climate change readiness. This tool is designed to (i) support leaders in Canadian health facilities and regional health authorities in designing mitigation and adaptation roadmaps, (ii) support decision-making for climate change-related strategic planning processes, and (iii) create a high-level overview of organizational readiness. This tool is intended to consolidate key data, provide a clear communication tool, allow for objective rapid baselining, enable system-level gap analysis, facilitate comparability/transparency, and support rapid learning cycles.

Climate action, staff engagement, and change management: A paediatric hospital case study

Planetary health and triple bottom line accounting are concepts healthcare organizations are starting to grapple with. While a few Canadian hospitals are early pioneers in efforts to deliver healthcare with less greenhouse gases, many hospitals struggle with adding a climate lens to their operations. This case study highlights a five year journey at CHEO to roll-out a hospital-wide climate strategy. CHEO has created new reporting structures, revised resource allocation, and launched net-zero targets. This hospital net-zero case study is an illustration of climate actions, given certain contexts, rather than a roadmap. Establishing this hospital-wide strategic pillar-during a global pandemic-has yielded (i) cost savings, (ii) an inspired workforce, and (iii) meaningful greenhouse gas reductions.

Cognitive Behavioral Therapy for Children With Headaches: Will an App Do the Trick?

Participants were enrolled into a pilot randomized-controlled 4-week trial comparing the efficacy and feasibility of app-based cognitive behavioral therapy (CBT) to a stretching program. Headache-related disability and quality of life were assessed using the Pediatric Migraine Disability Scale (PedMIDAS), Kidscree27, and Pediatric Quality of Life Inventory. Multivariable regression analysis were performed to assess the group effects in the presence of adherence and other covariates. Twenty participants completed the study. Adherence was significantly higher in the stretching than in the CBT app group (100% vs 54%, P < .034). When controlling for adherence and baseline scores, the stretching group showed greater reduction in PedMIDAS score (average: 29.2, P < .05) as compared to the CBT app group. However, in terms of the Quality-of-Life Indicators, pre- and postintervention raw scores were not significantly different between groups (P > .05). App-based CBT was not superior to a stretching program in reducing headache-related disability in a select population of pediatric headache patients. Future studies should assess if implementing features to the CBT app, like tailoring to pediatric age groups, would improve outcomes.

Normative values of renin and aldosterone in clinically stable preterm neonates

BACKGROUND

There is a paucity of literature on the normative levels of plasma renin concentration (PRC) and serum aldosterone (SA) in premature neonates. This study aims to provide normative data on PRC and SA levels in preterm neonates in the first 2 weeks after birth and explore associations with maternal, perinatal, or postnatal factors.

METHODS

Neonates born at 26- to 34-week gestation were recruited from two neonatal intensive care units in Canada and Australia. The direct renin assay PRC and SA were analyzed on day 1 and days 14-21 after birth to compare across categorical variables and to produce normative values.

RESULTS

A total of 262 subjects were enrolled from the Canadian (29%) and Australian (71%) sites. The mean gestational age was 30 weeks, with a mean birth weight of 1457 g. The normative values of PRC and SA for neonates born between 26 + 0 and 29 + 6 weeks and 30 + 0 and 34 + 0 weeks of gestation were produced for day 1 and day 14-21 after birth. Both PRC and SA increased from day 1 to day 14-21. The more premature neonates reached a higher PRC on days 14-21 after birth but exhibited lower SA levels on day 1 after birth. When comparing gender, birth weight, and maternal risk factor categories, no statistical differences in PRC or SA were found. A small but significant decrease in PRC, but not SA, was noted for neonates with placental pathology.

CONCLUSIONS

This study produced normative values of PRA and SA in clinically stable preterm neonates that can be referenced for use in clinical practice. A higher resolution version of the Graphical abstract is available as Supplementary information.

Pediatric and Adolescent Gynecology Practices: A National Survey of Canadian Gynecologists

OBJECTIVE

To identify 1) the current state of pediatric and adolescent gynecology (PAG) provision of care; 2) barriers to practicing PAG; and 3) the need for increased PAG training in residency and continuing medical education (CME).

METHODS

Obstetricians and gynecologists (OB/GYNs) across Canada who currently practice gynecology were asked to complete an anonymous, self-administered, Internet-based survey.

RESULTS

One-hundred and forty-seven OB/GYNs across Canada responded to the survey, and after applying exclusion criteria (retired gynecologists, medical students, postgraduate trainees, gynecologists who do not currently practice gynecology, PAG specialists, or OB/GYNs seeing predominantly pregnant adolescent women), 135 were included. Seventy-six percent of survey respondents stated that they care for pediatric and adolescent patients in their practice. The pathologies and surgeries they are comfortable managing are those that are similar to the adult population, such as intrauterine device insertion in the office/OR, adnexal detorsion, laparoscopy in patients over 12 years of age, examination under anesthesia, and hymenectomy. Respondents who stated wanting to learn more about PAG preferred either online learning modules (85%) or CME workshops at regional meetings (91%).

CONCLUSION

Canadian OB/GYNs provide PAG care with very little training to support their work. Attention must be given to better training for our residents via available curriculums and teaching modalities, as well as increased access to CME for OB/GYNs.

Nasopharyngeal swabs vs. saliva sampling for SARS-CoV-2 detection: A cross-sectional survey of acceptability for caregivers and children after experiencing both methods

Background

Saliva sampling is a promising alternative to nasopharyngeal swabs for SARS-CoV-2 testing, but acceptability data is lacking. We characterize the acceptability of saliva sampling and nasopharyngeal swabs for primary decision makers and their children after experiencing both testing modalities.

Methods

We administered a cross-sectional survey to participants aged 6-to-17 years and their primary decision makers at an Ottawa community COVID-19 testing centre in March 2021. Included were participants meeting local guidelines for testing. Excluded were those identified prior to participation as having inability to complete the consent, sampling, or survey process. Acceptability in multiple hypothetical scenarios was rated using a 5-point Likert scale. Pain was measured using the Faces Pain Scale—Revised (FPS-R). Preference for testing was assessed with direct binary questions.

Results

48 participants and 48 primary decision makers completed the survey. Nasopharyngeal swab acceptability differed between scenarios, ranging 79% [95%CI: 66, 88] to 100% [95%CI: 95, 100]; saliva sampling acceptability was similar across scenarios, ranging 92% [95%CI: 82, 97] to 98% [95%CI: 89, 99]. 58% of youth described significant pain with nasopharyngeal swabbing, versus none with saliva sampling. 90% of children prefer saliva sampling. 66% of primary decision makers would prefer nasopharyngeal swabbing if it were 10% more sensitive.

Conclusion

Though youth prefer saliva sampling over nasopharyngeal swabs, primary decision makers present for testing remain highly accepting of both. Acceptance of nasopharyngeal swabs, however, varies with the testing indication and is influenced by perceived test accuracy. Understanding factors that influence sampling acceptance will inform more successful testing strategies.

Targeting Epilepsy Through the Foremen Ovale: How Many Helical Needles are Needed?

Laser ablation of the hippocampus offers medically refractory epilepsy patients an alternative to invasive surgeries. Emerging commercial solutions deliver the ablator through a burr hole in the back of the head. We recently introduced a new access path through the foremen ovale, using a helical needle, which minimizes the amount of healthy brain tissue the needle must pass through on its way to the hippocampus, and also enables the needle to follow the medial axis of the hippocampus more closely. In this paper, we investigate whether helical needles should be designed and fabricated on a patient-specific basis as we had previously proposed, or whether a small collection of pre-defined needle shapes can apply across many patients. We propose a new optimization strategy to determine this needle set using patient data, and investigate the accuracy with which these needles can reach the the medial axis of the hippocampus. We find that three basic tube shapes (mirrored as necessary for left vs. right hippocampi) are all that is required, across 20 patient datasets (obtained from 10 patient CT scans), to reduce worst-case maximum error below 2 mm.

Risk of Mental Health Problems in Children and Youths Following Concussion

IMPORTANCE

Concussion may exacerbate existing mental health issues. Little evidence exists on whether concussion is associated with the onset of new psychopathologies or long-term mental health problems.

OBJECTIVE

To investigate associations between concussion and risk of subsequent mental health issues, psychiatric hospitalizations, self-harm, or suicides.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study including children and youths aged 5 to 18 years with a concussion or orthopedic injury incurred between April 1, 2010, and March 31, 2020, in Ontario, Canada. Participants had no previous mental health visit in the year before the index event for cohort entry and no prior concussion or traumatic brain injury 5 years before the index visit. Data were collected from provincewide health administrative databases. Participants with concussion were included in the exposed cohort, and those with an orthopedic injury were included in the comparison cohort; these groups were matched 1:2, respectively, on age and sex.

EXPOSURES

Concussion or orthopedic injury.

MAIN OUTCOMES AND MEASURES

The primary outcome was mental health problems, such as psychopathologies and psychiatric disorders, identified from health care visits in emergency departments, hospitalizations, or primary care settings. Secondary outcomes were psychiatric hospitalizations, self-harm health care visits, and death by suicide (identified in health care or vital statistics databases).

RESULTS

A total of 152 321 children and youths with concussion (median [IQR] age, 13 [10-16] years; 86 423 [56.7%] male) and 296 482 children and youths with orthopedic injury (median [IQR] age, 13 [10-16] years; 171 563 [57.9%] male) were matched by age and sex. The incidence rates of any mental health problem were 11 141 per 100 000 person-years (exposed group) and 7960 per 100 000 person-years (unexposed group); with a difference of 3181 (95% CI, 3073-3291) per 100 000 person-years. The exposed group had an increased risk of developing a mental health issue (adjusted hazard ratio [aHR], 1.39; 95% CI, 1.37-1.40), self-harm (aHR, 1.49; 95% CI, 1.42-1.56), and psychiatric hospitalization (aHR, 1.47; 95% CI, 1.41-1.53) after a concussion. There was no statistically significant difference in death by suicide between exposed and unexposed groups (HR, 1.54; 95% CI, 0.90-2.61).

CONCLUSIONS AND RELEVANCE

Among children and youths aged 5 to 18 years, concussion was associated with an increased risk of mental health issues, psychiatric hospitalization, and self-harm compared with children and youths with an orthopedic injury.

Health care costs of hospitalization of young children for respiratory syncytial virus infections: a population-based matched cohort study

BACKGROUND

Respiratory syncytial virus (RSV) infection poses a substantial clinical burden among infants and young children. We sought to determine the health care costs of hospitalizations attributable to RSV in Ontario, Canada, from the health care payer perspective.

METHODS

For this population-based matched cohort study, we identified children younger than 24 months who were or were not hospitalized with RSV infections in 2006-2016. We performed a cost-of-illness analysis using linked administrative health data, with subjects stratified by gestational age and congenital heart disease, and propensity score-matched on established risk factors. The primary outcome was attributable health care costs per patient, reflecting the difference in direct medical costs between the groups, calculated to 12 months postdischarge in 2020 Canadian dollars.

RESULTS

We identified 14 608 RSV-infected children, matched to 72 040 controls. The adjusted attributable cost of hospitalized RSV was $134 931 900 over 10 years, or $9240 per patient (95% confidence interval [CI] $8790-$9690). Health care costs escalated 3 days before hospitalization, and persisted up to 12 months after discharge. Increased costs were associated with major comorbidities, but not extreme premature birth. The highest mean attributable cost per patient was in the presence of hemodynamically significant heart disease ($60 110, 95% CI $26 700-$93 060). Infants born at 36-43 weeks' gestation constituted the greatest overall cost burden at $117 886 720.

INTERPRETATION

Although the greatest direct medical costs per patient hospitalized with RSV infection are among children with cardiac disease, the greatest overall cost burden is from children born at or near term, who are not targeted by current prophylaxis strategies. The substantial attributable health care costs of RSV can inform cost-effectiveness analyses of novel RSV vaccines and prioritization of health care resources.

Poor adherence to sleep and physical activity guidelines among children with epilepsy

OBJECTIVE

To assess physical activity and sleep rates in a cohort of children with epilepsy (CWE) and determine if there is a relationship between physical activity and sleep time.

METHODS

Children aged 8-14 years with a diagnosis of epilepsy and at least one seizure in the past 12 months were monitored via a wrist-worn activity tracker for 16 weeks, to objectively measure daily physical activity, as assessed by step counts, and sleep time. Adherence to physical activity (≥12,000 steps/day) and sleep recommendations (≥9 h for children aged 8-12 years, or ≥8 h for children aged 13-15 years) was determined. To predict daily activity or nightly sleep, a series of multivariable models incorporating age, sex, day-type (all combinations of weekday or weekend and summer holiday or school), participant (as a random effect), daily physical activity (for models predicting sleep), nightly sleep (for models predicting physical activity), and autoregressive terms of previous sleep or physical activity were constructed, and the best-performing models were selected with Akaike information criterion analysis.

RESULTS

Twenty-two children with mild to moderate epilepsy were recruited (54.5% female, median (IQR) age 11 (10, 13) years) and monitored for 16 weeks. They met the recommended level of physical activity only in 38.0% (21.7%, 59.4%), and sleep in 49.1% (30.0%, 68.5%) of days. They met both physical activity and sleep guidelines on the same day in only 17.8% (95% CI 7.1%, 38.0%). There was no association between meeting the recommended levels of daily physical activity and sleep time (p = 0.86, ρ = 0.03). In the best-performing model, age, sex, day type, and participant explained 28.9% of the variance in daily physical activity, with no additional insight provided by measures of sleep time. Age, sex, day type, participant, and daily physical activity explained 17.3% of the variance in nightly sleep time, with a statistically discernable but small association between physical activity and sleep time (1.79 ± 0.53, p = 0.001).

CONCLUSION

Our cohort of children with mild to moderate epilepsy showed poor adherence to sleep and physical activity guidelines. There was no clinically relevant association between daily physical activity and sleep among these children who were similarly active to healthy peers. Future studies should assess the effect of increased sleep hygiene and physical activity on overall well-being and seizure control in CWE.

Nonauscultatory clinical criteria are sensitive for cardiac pathology in low-risk paediatric heart murmurs

Background

Healthy children with likely innocent heart murmurs are frequently referred to cardiologists for reassurance. Existing guidelines that advise against these referrals are not consistently followed partly because they involve subjective auscultatory judgements with which many care providers are uncomfortable. Here, we investigate whether clinical criteria with no subjective auscultatory component are sensitive for cardiac pathology.

Methods

A retrospective chart review was performed of all new patients seen in our paediatric cardiology clinic for assessment of a murmur from January 1, 2016 through June 30, 2018. Patients were characterized as "low-risk" if they met all of the following criteria: asymptomatic; normal physical examination other than the murmur; no risk factors for congenital heart disease; and age over 12 months. The primary outcomes were the sensitivity for ruling out pathology and the negative predictive value of the proposed criteria.

Results

Of 915 total patients, 214 met the low-risk criteria. The sensitivity of our criteria for ruling out pathology was 97.2% (95% confidence interval 94.1% to 99.0%) and the negative predictive value was also 97.2% (95% confidence interval 94.0% to 98.7%). Six of the 214 low-risk patients had pathology (2.8%; 95% confidence interval 1.3% to 6.0%), none of which has required intervention since diagnosis. Each of these six children had a murmur that sounded pathological to the auscultating cardiologist.

Conclusions

Basic clinical criteria that do not require auscultation are highly sensitive for ruling out significant cardiac pathology in children over 12 months of age.

Continuous EEG in a Pediatric Intensive Care Unit: Adherence to Monitoring Criteria and Barriers to Adequate Implementation

BACKGROUND

Subclinical seizures are common in critically ill children and are best detected by continuous EEG (cEEG) monitoring. Timely detection of seizures requires pediatric intensive care unit (PICU) physicians to identify patients at risk of seizures and request cEEG monitoring. A recent consensus statement from the American Clinical Neurophysiology Society (ACNS) outlines the indications for cEEG monitoring in critically ill patients. However, adherence to these cEEG monitoring criteria among PICU physicians is unknown. Our project had two goals: 1. To assess adherence to cEEG monitoring indications and barriers toward their implementation; 2. To improve compliance with the ACNS cEEG monitoring criteria in our PICU.

METHODS

This is a single-institution study. A total of 234 PICU admissions (183 unique patients) were studied. A 6-month retrospective chart review identified PICU patients meeting ACNS criteria for cEEG monitoring, and patients for whom monitoring was requested. This was followed by an 8-week quality improvement project. During this mentorship period, a didactic 15-min lecture and summary handouts regarding the ACNS indications for cEEG monitoring were provided to all PICU physicians. Requests for cEEG monitoring during the mentorship period were compared to baseline adherence to cEEG monitoring recommendations, and barriers toward timely cEEG monitoring were assessed.

RESULTS

Nearly every fifth PICU patient met cEEG monitoring indications, and prevalences of patients meeting those indications were similar in the retrospective and the prospective mentorship period (18% vs. 19%). Almost all patients (98%) requiring cEEG as per ACNS criteria met the indication for monitoring already at the time of their PICU admission. During the retrospective period, 23% of patients meeting ACNS criteria had a request for cEEG monitoring, which increased to 83% during the mentorship period. The median delay to cEEG initiation was 16.7 h during the mentorship period, largely due to limited hours of EEG technician availability. Electrographic seizures were identified in 36% of patients monitored, all within the first 120 min of cEEG recording. The majority (79%) of cEEGs informed clinical management.

CONCLUSIONS

A brief teaching intervention supplemented by pictographic handouts significantly increased adherence to cEEG monitoring recommendations, and cEEGs guided clinical management. However, there were long delays to cEEG initiation. In order to promptly recognize subclinical seizures in critically ill children, we strongly advocate for a routine screening for cEEG monitoring indications as part of the PICU admission process, and a care model allowing for cEEG initiation around-the-clock.

No improvement in quality of life in children with epilepsy treated with the low glycemic index diet

BACKGROUND

Up to 30% of children with epilepsy show a poor therapeutic response to pharmacologic treatment. Ketogenic diets, including the less strict low glycemic index treatment (LGIT), may improve seizure control in pharmacoresistant epilepsy. However, little is known about the quality of life (QoL) in children on LGIT. To explore psychosocial implications of the LGIT on pediatric patients and their caregivers, we have conducted a pilot study to explore the QoL of children and adolescents on the diet.

METHODS

Pediatric patients on LGIT and their parents completed standardized, validated QoL questionnaires (Pediatric Quality of Life Epilepsy Module), one retrospectively and one while being on LGIT. An additional questionnaire included two open-ended questions in order to gain a better understanding of personal experiences of families.

RESULTS

We enrolled six patients with epilepsy on LGIT between the age of 3 and 13 years. Self-reported QoL decreased in all adolescents, regardless of improvement in seizure control. Parent-reported QoL improved in three of six participants, remained stable in one, and decreased in two patients (both displayed no seizure improvement). Parents and adolescents reported positive experiences of trying new foods and being more health conscious, as well as negative themes such as social isolation and meal preparation difficulties.

CONCLUSIONS

The lack of improvement in patient-reported QoL points towards an overall negative impact of the LGIT on patient well-being, despite positive effects on seizure control. Our preliminary results indicate that the benefits of seizure control may subjectively be outweighed by adverse social effects of the LGIT. Families should be made aware of psychosocial risks of the diet. Whenever possible, children should be part of the therapeutic decision-making process. Larger prospective studies are required to fully assess the overall impact of the LGIT.

The (Under)Use of Eye-Tracking in Evolutionary Ecology

To survive and pass on their genes, animals must perform many tasks that affect their fitness, such as mate-choice, foraging, and predator avoidance. The ability to make rapid decisions is dependent on the information that needs to be sampled from the environment and how it is processed. We highlight the need to consider visual attention within sensory ecology and advocate the use of eye-tracking methods to better understand how animals prioritise the sampling of information from their environments prior to making a goal-directed decision. We consider ways in which eye-tracking can be used to determine how animals work within attentional constraints and how environmental pressures may exploit these limitations.

Novel Miscanthus genotypes selected for different drought tolerance phenotypes show enhanced tolerance across combinations of salinity and drought treatments

BACKGROUND AND AIMS

Water deficit and salinity stresses are often experienced by plants concurrently; however, knowledge is limited about the effects of combined salinity and water deficit stress in plants, and especially in C4 bioenergy crops. Here we aim to understand how diverse drought tolerance traits may deliver tolerance to combinations of drought and salinity in C4 crops, and identify key traits that influence the productivity and biomass composition of novel Miscanthus genotypes under such conditions.

METHODS

Novel genotypes used included M. sinensis and M. floridulus species, pre-screened for different drought responses, plus the commercial accession Miscanthus × giganteus (M×g.). Plants were grown under control treatments, single stress or combinations of water deficit and moderate salinity stress. Morphophysiological responses, including growth, yield, gas exchange and leaf water relations and contents of proline, soluble sugars, ash and lignin were tested for significant genotypic and treatment effects.

KEY RESULTS

The results indicated that plants subjected to combined stresses showed more severe responses compared with single stresses. All novel drought-tolerant genotypes and M×g. were tolerant to moderate salinity stress. Biomass production in M. sinensis genotypes was more resilient to co-occurring stresses than that in M×g. and M. floridulus, which, despite the yield penalty produced more biomass overall. A stay-green M. sinensis genotype adopted a conservative growth strategy with few significant treatment effects. Proline biosynthesis was species-specific and was triggered by salinity and co-occurring stress treatments, mainly in M. floridulus. The ash content was compartmentalized differently in leaves and stems in the novel genotypes, indicating different mechanisms of ion accumulation.

CONCLUSIONS

This study highlights the potential to select novel drought-tolerant Miscanthus genotypes that are resilient to combinations of stress and is expected to contribute to a deeper fundamental knowledge of different mechanistic responses identified for further exploitation in developing resilient Miscanthus crops.

Combined Conventional and Amplitude-Integrated EEG Monitoring in Neonates: A Prospective Study

BACKGROUND/OBJECTIVE

Seizure monitoring via amplitude-integrated EEG is standard of care in many neonatal intensive care units; however, conventional EEG is the gold standard for seizure detection. We compared the diagnostic yield of amplitude-integrated EEG interpreted at the bedside, amplitude-integrated EEG interpreted by an expert, and conventional EEG.

METHODS

Neonates requiring seizure monitoring received amplitude-integrated EEG and conventional EEG in parallel. Clinical events and amplitude-integrated EEG were interpreted at bedside. Subsequently, amplitude-integrated EEG and conventional EEG were independently analyzed by experienced neonatology and neurology readers. Sensitivity and specificity of bedside amplitude-integrated EEG as compared to expert amplitude-integrated EEG interpretation and conventional EEG were evaluated.

RESULTS

Thirteen neonates were monitored for an average duration of 33 hours (range 15-94, SD 25). Fourteen seizure-like events were detected by clinical observation, and 12 others by bedside amplitude-integrated EEG analysis. One of the clinical, and none of the bedside amplitude-integrated EEG events were confirmed as seizures on conventional EEG. Post hoc expert amplitude-integrated EEG interpretation revealed eight suspected seizures, all different from the ones detected by the bedside amplitude-integrated EEG team, of which one was confirmed via conventional EEG. Eight seizures were recorded on conventional EEG. Expert amplitude-integrated EEG interpretation had a sensitivity of 13% with 46% specificity for individual seizure detection, and a sensitivity of 50% with 46% specificity for detecting patients with seizures.

CONCLUSION

Real-world bedside amplitude-integrated EEG monitoring failed to detect all seizures evidenced via conventional EEG, while misclassifying other events as seizures. Even post hoc expert amplitude-integrated EEG interpretation provided limited sensitivity and specificity. Considering the poor sensitivity and specificity of bedside amplitude-integrated EEG interpretation, combined monitoring may provide limited clinical benefit.

Discovering human germ cell mutagens with whole genome sequencing: Insights from power calculations reveal the importance of controlling for between-family variability

Mutations in germ cells pose potential genetic risks to offspring. However, de novo mutations are rare events that are spread across the genome and are difficult to detect. Thus, studies in this area have generally been under-powered, and no human germ cell mutagen has been identified. Whole Genome Sequencing (WGS) of human pedigrees has been proposed as an approach to overcome these technical and statistical challenges. WGS enables analysis of a much wider breadth of the genome than traditional approaches. Here, we performed power analyses to determine the feasibility of using WGS in human families to identify germ cell mutagens. Different statistical models were compared in the power analyses (ANOVA and multiple regression for one-child families, and mixed effect model sampling between two to four siblings per family). Assumptions were made based on parameters from the existing literature, such as the mutation-by-paternal age effect. We explored two scenarios: a constant effect due to an exposure that occurred in the past, and an accumulating effect where the exposure is continuing. Our analysis revealed the importance of modeling inter-family variability of the mutation-by-paternal age effect. Statistical power was improved by models accounting for the family-to-family variability. Our power analyses suggest that sufficient statistical power can be attained with 4-28 four-sibling families per treatment group, when the increase in mutations ranges from 40 to 10% respectively. Modeling family variability using mixed effect models provided a reduction in sample size compared to a multiple regression approach. Much larger sample sizes were required to detect an interaction effect between environmental exposures and paternal age. These findings inform study design and statistical modeling approaches to improve power and reduce sequencing costs for future studies in this area.

Hemlock Woolly Adelgid (Hemiptera: Adelgidae) Abundance and Hemlock Canopy Health Numerous Years After Imidacloprid Basal Drench Treatments: Implications for Management Programs

Hemlock woolly adelgid (Adelges tsugae [Annand]), an invasive insect in the eastern United States, has caused widespread decline of eastern hemlock, Tsuga canadensis (L.) Carriére. Imidacloprid basal drench treatments were assessed 4-7 yr after a single treatment to determine hemlock woolly adelgid population suppression and effects on hemlock canopy health. The effects of sampling site, years post-treatment, and hemlock diameter at breast height (DBH) size classes were evaluated relative to imidacloprid treatment on hemlock woolly adelgid populations and hemlock canopy health characteristics. The influence of hemlock woolly adelgid populations on canopy health characteristics was also assessed. Imidacloprid treatments resulted in low-level hemlock woolly adelgid populations 7 yr post-treatment. Hemlock woolly adelgid was present on more hemlocks 7 yr compared with 4-6 yr post-treatment. Smaller hemlocks, dosed with 0.7 g active ingredient (AI)/2.5 cm DBH, had higher populations of hemlock woolly adelgid than the largest size class, which were treated at twice that dosage. Concentrations of imidacloprid and its olefin metabolite below the LC₅₀ were sufficient for suppression of hemlock woolly adelgid populations, which suggests an additive effect of imidacloprid and olefin that compounds hemlock woolly adelgid mortality over many generations. Hemlock woolly adelgid populations observed in this study were too low to have an observable effect on hemlock canopy health, indicating that application intervals of up to 7 yr may be adequate to protect hemlocks.

High C3 photosynthetic capacity and high intrinsic water use efficiency underlies the high productivity of the bioenergy grass Arundo donax

Arundo donax has attracted interest as a potential bioenergy crop due to a high apparent productivity. It uses C3 photosynthesis yet appears competitive with C4 grass biomass feedstock's and grows in warm conditions where C4 species might be expected to be that productive. Despite this there has been no systematic study of leaf photosynthetic properties. This study determines photosynthetic and photorespiratory parameters for leaves in a natural stand of A. donax growing in southern Portugal. We hypothesise that A. donax has a high photosynthetic potential in high and low light, stomatal limitation to be small and intrinsic water use efficiency unusually low. High photosynthetic rates in A. donax resulted from a high capacity for both maximum Rubisco (Vc,max 117 μmol CO2 m(-2) s(-1)) and ribulose-1:5-bisphosphate limited carboxylation rate (Jmax 213 μmol CO2 m(-2) s(-1)) under light-saturated conditions. Maximum quantum yield for light-limited CO2 assimilation was also high relative to other C3 species. Photorespiratory losses were similar to other C3 species under the conditions of measurement (25%), while stomatal limitation was high (0.25) resulting in a high intrinsic water use efficiency. Overall the photosynthetic capacity of A. donax is high compared to other C3 species, and comparable to C4 bioenergy grasses.

The effect of oil sands process-affected water and model naphthenic acids on photosynthesis and growth in Emiliania huxleyi and Chlorella vulgaris

Naphthenic acids (NAs) are among the most toxic organic pollutants present in oil sands process waters (OSPW) and enter marine and freshwater environments through natural and anthropogenic sources. We investigated the effects of the acid extractable organic (AEO) fraction of OSPW and individual surrogate NAs, on maximum photosynthetic efficiency of photosystem II (PSII) (FV/FM) and cell growth in Emiliania huxleyi and Chlorella vulgaris as representative marine and freshwater phytoplankton. Whilst FV/FM in E. huxleyi and C. vulgaris was not inhibited by AEO, exposure to two surrogate NAs: (4'-n-butylphenyl)-4-butanoic acid (n-BPBA) and (4'-tert-butylphenyl)-4-butanoic acid (tert-BPBA), caused complete inhibition of FV/FM in E. huxleyi (≥10 mg L(-1)n-BPBA; ≥50 mg L(-1)tert-BPBA) but not in C. vulgaris. Growth rates and cell abundances in E. huxleyi were also reduced when exposed to ≥10 mg L(-1)n- and tert-BPBA; however, higher concentrations of n- and tert-BPBA (100 mg L(-1)) were required to reduce cell growth in C. vulgaris. AEO at ≥10 mg L(-1) stimulated E. huxleyi growth rate (p ≤ 0.002), yet had no apparent effect on C. vulgaris. In conclusion, E. huxleyi was generally more sensitive to NAs than C. vulgaris. This report provides a better understanding of the physiological responses of phytoplankton to NAs which will enable improved monitoring of NA pollution in aquatic ecosystems in the future.

Assessment of Imidacloprid and Its Metabolites in Foliage of Eastern Hemlock Multiple Years Following Treatment for Hemlock Woolly Adelgid, Adelges tsugae (Hemiptera: Adelgidae), in Forested Conditions

Widespread decline and mortality of eastern hemlock, Tsuga canadensis (L.) Carrière, have been caused by hemlock woolly adelgid, Adelges tsugae (Annand) (HWA) (Hemiptera: Adelgidae). The current study is a retrospective analysis conducted in collaboration with Great Smoky Mountains National Park (GRSM) to determine longevity of imidacloprid and its insecticidal metabolites (imidacloprid olefin, 5-hydroxy, and dihydroxy) in GRSM's HWA integrated pest management (IPM) program. Foliage samples were collected from three canopy strata of hemlocks that were given imidacloprid basal drench treatments 4-7 yr prior to sampling. Foliage was analyzed to assess concentrations in parts per billion (ppb) of imidacloprid and its metabolites. Imidacloprid and its olefin metabolite were present in most, 95 and 65%, respectively, branchlets 4-7 yr post-treatment, but the 5-hydroxy and dihydroxy metabolites were present in only 1.3 and 11.7%, respectively, of the branchlets. Imidacloprid and olefin concentrations significantly decreased between 4 and 7 yr post-treatment. Concentrations of both imidacloprid and olefin were below the LC50 for HWA 5-7 yr post-treatment. Knowledge of the longevity of imidacloprid treatments and its metabolite olefin can help maximize the use of imidacloprid in HWA IPM programs.

Does disruptive camouflage conceal edges and features?

Camouflage is ubiquitous in the natural world and benefits both predators and prey. Amongst the range of concealment strategies, disruptive coloration is thought to visually fragment an animal’s’ outline, thereby reducing its rate of discovery. Here, I propose two non-mutually exclusive hypotheses for how disruptive camouflage functions, and describe the visual mechanisms that might underlie them. (1) The local edge disruption hypothesis states that camouflage is achieved by breaking up edge information. (2) The global feature disruption hypothesis states camouflage is achieved by breaking up the characteristic features of an animal (e.g., overall shape or facial features). Research clearly shows that putatively disruptive edge markings do increase concealment; however, few tests have been undertaken to determine whether this survival advantage is attributable to the distortion of features, so the global feature disruption hypothesis is under studied. In this review the evidence for global feature disruption is evaluated. Further, I address if object recognition processing provides a feasible mechanism for animals’ features to influence concealment. This review concludes that additional studies are needed to test if disruptive camouflage operates through the global feature disruption and proposes future research directions.

The aggregation of early-onset melanoma in young Western Australian families

BACKGROUND

Few studies have examined the familial aggregation of melanoma or its co-aggregation with other cancers using whole-population based designs. This study aimed to investigate aggregation patterns in young Western Australian families, using population-based linked health data to identify individuals born in Western Australia between 1974 and 2007, their known relatives, and all incident cancer diagnoses within the resulting 1,506,961 individuals.

METHODS

Cox proportional hazards regression models were used to compare the risk of melanoma for first-degree relatives of melanoma cases to that for first-degree relatives of controls, with bootstrapping used to account for correlations within families. The risk of (i) developing melanoma based on the number of first-degree relatives with other cancers, and (ii) developing non-melanoma cancers based on the number of first-degree relatives diagnosed with melanoma was also investigated.

RESULTS

First-degree relatives of melanoma cases had a significantly greater incidence of melanoma than first-degree relatives of individuals not affected with melanoma (Hazard Ratio (HR)=3.58, 95% bootstrap confidence interval (CI): 2.43-5.43). Sensitivity analyses produced a higher hazard ratio estimate when restricted to melanoma cases diagnosed before 40 years of age (HR=3.77, bootstrap 95% CI: 2.49-6.39) and a lower estimate when only later-onset cases (>40 years) were considered (HR=2.45, bootstrap 95% CI: 1.23-4.82). No significant evidence was found for co-aggregation between melanoma and any other cancers.

CONCLUSIONS

Results indicated a strong familial basis of melanoma, with the higher than expected hazard ratio observed likely to reflect early-age at onset cases in this young cohort, supported by the results of the sensitivity analyses. Exploratory analyses suggested that the determinants of melanoma causing the observed aggregation within families may be independent of other malignancies, although these analyses were limited by the young age of the sample. Determining familial aggregation patterns will provide valuable knowledge regarding improved clinical risk prediction and the underlying biological mechanisms of melanoma and other cancers.

Disruptive camouflage impairs object recognition

Whether hiding from predators, or avoiding battlefield casualties, camouflage is widely employed to prevent detection. Disruptive coloration is a seemingly well-known camouflage mechanism proposed to function by breaking up an object's salient features (for example their characteristic outline), rendering objects more difficult to recognize. However, while a wide range of animals are thought to evade detection using disruptive patterns, there is no direct experimental evidence that disruptive coloration impairs recognition. Using humans searching for computer-generated moth targets, we demonstrate that the number of edge-intersecting patches on a target reduces the likelihood of it being detected, even at the expense of reduced background matching. Crucially, eye-tracking data show that targets with more edge-intersecting patches were looked at for longer periods prior to attack, and passed-over more frequently during search tasks. We therefore show directly that edge patches enhance survivorship by impairing recognition, confirming that disruptive coloration is a distinct camouflage strategy, not simply an artefact of background matching.

A study on the theoretical and practical accuracy of conoscopic holography-based surface measurements: toward image registration in minimally invasive surgery

BACKGROUND

Registered medical images can assist with surgical navigation and enable image-guided therapy delivery. In soft tissues, surface-based registration is often used and can be facilitated by laser surface scanning. Tracked conoscopic holography (which provides distance measurements) has been recently proposed as a minimally invasive way to obtain surface scans. Moving this technique from concept to clinical use requires a rigorous accuracy evaluation, which is the purpose of our paper.

METHODS

We adapt recent non-homogeneous and anisotropic point-based registration results to provide a theoretical framework for predicting the accuracy of tracked distance measurement systems. Experiments are conducted a complex objects of defined geometry, an anthropomorphic kidney phantom and a human cadaver kidney.

RESULTS

Experiments agree with model predictions, producing point RMS errors consistently < 1 mm, surface-based registration with mean closest point error < 1 mm in the phantom and a RMS target registration error of 0.8 mm in the human cadaver kidney.

CONCLUSIONS

Tracked conoscopic holography is clinically viable; it enables minimally invasive surface scan accuracy comparable to current clinical methods that require open surgery.

Percutaneous inner-ear access via an image-guided industrial robot system

Image-guided robots have been widely used for bone shaping and percutaneous access to interventional sites. However, due to high-accuracy requirements and proximity to sensitive nerves and brain tissues, the adoption of robots in inner-ear surgery has been slower. In this paper the authors present their recent work towards developing two image-guided industrial robot systems for accessing challenging inner-ear targets. Features of the systems include optical tracking of the robot base and tool relative to the patient and Kalman filter-based data fusion of redundant sensory information (from encoders and optical tracking systems) for enhanced patient safety. The approach enables control of differential robot positions rather than absolute positions, permitting simplified calibration procedures and reducing the reliance of the system on robot calibration in order to ensure overall accuracy. Lastly, the authors present the results of two phantom validation experiments simulating the use of image-guided robots in inner-ear surgeries such as cochlear implantation and petrous apex access.

Behaviourally mediated crypsis in two nocturnal moths with contrasting appearance

The natural resting orientations of several species of nocturnal moth on tree trunks were recorded over a three-month period in eastern Ontario, Canada. Moths from certain genera exhibited resting orientation distributions that differed significantly from random, whereas others did not. In particular, Catocala spp. collectively tended to orient vertically, whereas subfamily Larentiinae representatives showed a variety of orientations that did not differ significantly from random. To understand why different moth species adopted different orientations, we presented human subjects with a computer-based detection task of finding and 'attacking' Catocala cerogama and Euphyia intermediata target images at different orientations when superimposed on images of sugar maple (Acer saccharum) trees. For both C. cerogama and E. intermediata, orientation had a significant effect on survivorship, although the effect was more pronounced in C. cerogama. When the tree background images were flipped horizontally the optimal orientation changed accordingly, indicating that the detection rates were dependent on the interaction between certain directional appearance features of the moth and its background. Collectively, our results suggest that the contrasting wing patterns of the moths are involved in background matching, and that the moths are able to improve their crypsis through appropriate behavioural orientation.

The association of common genetic variants in the APOA5, LPL and GCK genes with longitudinal changes in metabolic and cardiovascular traits

AIMS/HYPOTHESIS

Common genetic variants influence plasma triacylglycerol, HDL-cholesterol (HDL-C) and glucose levels in cross-sectional studies. However, the longitudinal effects of these established variants have not been studied. Our aim was to examine the longitudinal associations of four such variants in the apolipoprotein A-V (APOA5), lipoprotein lipase (LPL), and glucokinase (GCK) genes with fasting glucose or lipid levels.

METHODS

The individuals analysed were participants in the Busselton Health Survey (n = 4,554). Cross-sectional analyses of family data used the total association test. Longitudinal association analyses of unrelated participant data (n = 2,864) used linear mixed-effects models.

RESULTS

The findings of cross-sectional association analyses replicated those of previous studies. We observed associations of the G and C alleles at the APOA5 single nucleotide polymorphisms (SNPs) rs662799 and rs3135506 with raised triacylglycerol levels (p = 0.0003 and p < 0.0001, respectively), the 447X allele at the LPL SNP rs328 with reduced triacylglycerol levels (p = 0.0004) and raised HDL-C levels (p = 0.0004), and the A allele of the GCK SNP rs1799884 with raised fasting glucose level (p = 0.015). Longitudinal association analyses showed that most of these associations did not change in the same individuals over an average follow-up time of 17.4 years, though there was some evidence that the association of the 447X allele of rs328 with raised HDL-C level significantly increased with age (p = 0.01), and that the association of the C allele of rs3135506 with raised triacylglycerol level significantly increased over time (p = 0.0007).

CONCLUSIONS/INTERPRETATION

The current study suggests that the effects of established gene variants on lipid and glucose traits do not tend to alter with age during adulthood or over time.

Sphingosine effects on the contractile behavior of skinned cardiac myocytes

Sphingosine modulates myocyte beating behavior by acting on the sarcoplasmic reticulum calcium release channel, the ryanodine receptor. Chemically skinned myocytes isolated from adult rabbit ventricles exhibited spontaneous asynchonous contractions in response to micromolar levels of calcium. These cells do not have a functional sarcolemma but exhibit spontaneous contraction-relaxation cycles which are controlled by the sarcoplasmic reticulum. The intracellular second messenger, sphingosine, significantly reduced myocyte beat frequency in a biphasic manner with an IC50 of c. 0.5 microM. A computerized video-enhancement micrography system was used to determine the effect of sphingosine on sarcomere contractile parameters and to determine the potential source of the altered beating behavior produced by sphingosine. Contraction parameters related to sarcomere shortening were unaffected by sphingosine in the submicromolar range, suggesting that sphingosine had no effect on the contractile machinery itself. However, submicromolar sphingosine had a significant inhibitory effect on the spread of activation from sarcomere to sarcomere in these cells. Activation waves were propagated with an average velocity of 331 and 199 microns/s in control and sphingosine (0.58 microM) treated cells, respectively. Permeabilized myocyte calcium uptake was markedly increased by treatment with sphingosine, consistent with an inhibitory effect of sphingosine on sarcoplasmic reticulum calcium release. Sphingosine blocked calcium-induced calcium release from isolated cardiac sarcoplasmic reticulum membranes containing the ryanodine receptor. The results suggest that the site of sphingosine action on calcium signaling and beating behavior in the cardiac cell is the sarcoplasmic reticulum ryanodine receptor. By inhibiting channel opening sphingosine may increase the calcium threshold necessary to trigger calcium-induced calcium release, thus modulating cardiac excitation-contraction coupling.

Relationship between inducible H-2 expression and the immunogenicity of murine skin neoplasms. I. Evidence that the immunogenicity of ultraviolet radiation-chemically induced tumors is associated with their susceptibility to gamma-interferon-mediated enhancement of H-2Kk expression

Our objective was to determine the relationship between major histocompatibility complex class I molecule expression and the tumorigenic properties of cutaneous neoplasms induced by ultraviolet radiation or chemical carcinogens. All tumors tested were found to express low constitutive levels of MHC class I molecules in vitro as determined by indirect immunofluorescence and flow cytometry. Those tumors capable of growth in UVR-exposed but not in normal recipients (regressors) were found to express enhanced levels of H-2Kk following incubation in the presence of gamma-IFN. In contrast, only one of the tumors that were capable of growth in normal recipients (progressors) exhibited more than moderate enhancement of H-2Kk expression in response to gamma-IFN. Analysis of tumor variants obtained by conversion of a UVR-induced regressor tumor to the progressor phenotype by passage through sublethally gamma-irradiated hosts, or the generation of regressor tumors by mutagen exposure of a benz [A] pyrene (BAP) induced progressor tumor, further supported the direct relationship between tumor immunogenicity in vivo and the capacity to elevate H-2Kk expression in response to gamma-IFN. No correlation existed between H-2Dk expression by the tumors and their transplantation phenotype. Furthermore, we failed to observe MHC class II expression by any of the tumors tested. Finally, the growth rate of a regressor tumor implanted into UVR-exposed hosts was significantly reduced if the tumor was pretreated with gamma-IFN in vitro prior to inoculation. This result suggests that UVR-exposed animals may be deficient in their ability to enhance the expression of MHC class I molecules on developing tumors. This alteration may, in part, account for the state of tumor susceptibility caused by UVR exposure.