Effects of 24-week prebiotic intervention on self-reported upper respiratory symptoms, gastrointestinal symptoms, and markers of immunity in elite rugby union players

OBJECTIVES

Elite rugby union players face numerous physiological and psychological stressors which can increase upper respiratory and gastrointestinal illness risk, and in turn can compromise training and competitive performance. This study aimed to investigate the effect of daily prebiotic supplementation on upper respiratory symptoms, gastrointestinal symptoms, and markers of immune function in elite rugby union players.

METHODS

Thirty-three elite rugby union players were randomly assigned to consume a prebiotic (2.8 g/day galactooligosaccharide) or placebo (2.8 g/day maltodextrin), daily for 168 days under double-blind conditions. Participants completed daily and weekly questionnaires for self-reported upper respiratory and gastrointestinal symptoms respectively. Blood and saliva samples were collected at 0, 84, and 168 days for assessment of plasma TNF-α and CRP, and saliva IgA respectively.

RESULTS

The prebiotic group experienced a 2-day reduction in upper respiratory symptom duration (P = 0.045). Gastrointestinal symptom severity and incidence were lower in the prebiotic group compared to the placebo group (P < 0.001, P = 0.041) respectively. Salivary immunoglobulin A secretion rate was 42% greater in the prebiotic group compared to the placebo group at day 168 (P = 0.004), no differences in CRP and TNF-α were found (P > 0.05).

CONCLUSION

A 168-day dietary prebiotic intervention reduced the duration of upper respiratory symptoms and reduced the incidence and severity of gastrointestinal symptoms in elite rugby union players. These findings suggest that seasonal prebiotic interventions may be beneficial for reducing illness in elite rugby union players, improving their availability to train and compete.Key pointsElite athletes are susceptible to upper respiratory symptoms and gastrointestinal symptoms which may impact upon training availability and competition performance.For the first time, this study shows that a dietary prebiotic intervention can reduce the duration of upper respiratory symptoms by 2 days in elite rugby union players.Dietary prebiotic supplementation can improve the incidence and severity of gastrointestinal symptoms experienced by elite rugby union players.Prebiotic supplementation was able to increase salivary IgA secretion after 168 days.These findings can inform practice suggesting that seasonal prebiotic use has the potential to modulate immune function and reduce illness in elite rugby union, which may improve a player's availability to train and compete.The mechanisms by which prebiotics reduce URS and GIS require further research exploration.

The STAMPEDE2 Trial: a Site Survey of Current Patterns of Care, Access to Imaging and Treatment of Metastatic Prostate Cancer

AIMS

The forthcoming STAMPEDE2 trial has three comparisons in metastatic hormone-sensitive prostate cancer. We aim to determine clinical practices among STAMPEDE trial investigators for access to imaging and therapeutic choices and explore their interest in participation in STAMPEDE2.

MATERIALS AND METHODS

The survey was developed and distributed online to 120 UK STAMPEDE trial sites. Recipients were invited to complete the survey between 16 and 30 May 2022. The survey consisted of 30 questions in five sections on access to stereotactic ablative body radiotherapy (SABR), 177lutetium-prostate-specific membrane antigen-617 (177Lu-PSMA-617), choice of systemic therapies and use of positron emission tomography/computerised tomography and whole-body magnetic resonance imaging.

RESULTS

From 58/120 (48%) sites, 64 respondents completed the survey: 55/64 (86%) respondents were interested to participate in SABR, 44/64 (69%) in 177Lu-PSMA-617 and 56/64 (87.5%) in niraparib with abiraterone comparisons; 45/64 (70%) respondents had access to bone, spine and lymph node metastases SABR delivery and 7/64 (11%) to 177Lu-PSMA-617. In addition to androgen deprivation therapy, 60/64 (94%) respondents used androgen receptor signalling inhibitors and 46/64 (72%) used docetaxel; 29/64 (45%) respondents would consider triplet therapy with androgen deprivation therapy, androgen receptor signalling inhibitors and docetaxel. Positron emission tomography/computerised tomography was available to 62/64 (97%) respondents and requested by 45/64 (70%) respondents for disease uncertainty on conventional imaging and 39/64 (61%) at disease relapse. Whole-body magnetic resonance imaging was available to 24/64 (38%) respondents and requested by 13/64 (20%) respondents in highly selected patients. In low-volume disease, 38/64 (59%) respondents requested scans at baseline and disease relapse. In high-volume disease, 29/64 (45%) respondents requested scans at baseline, best response (at prostate-specific antigen nadir) and disease relapse; 54/64 (84%) respondents requested computerised tomography and bone scan for best response assessment.

CONCLUSION

There is noteworthy disparity in clinical practice across current study sites, however most have expressed an interest in participation in the forthcoming STAMPEDE2 trial.

Case Report: Caveolin‐1 Associated with Severe (Pediatric‐onset) Presentation of Pulmonary Arterial Hypertension

There has been a growing interest in the role that genetic factors influence pediatric pulmonary vascular disease. In fact, data suggests that genetic factors contribute to ~42% of pediatric‐onset pulmonary hypertension. Although animal and human studies suggest that aberrations in Caveolin1 (CAV1) signaling participate in the development of pulmonary vascular disorders, limited reports of CAV1‐associated heritable pulmonary arterial hypertension (HPAH) exist. This is a case report of a 2‐year‐old female with late recognition of HPAH due to a CAV1 pathogenic variant: c.474del, (p.Leu159Serfs*22)(NM_001753.5). The pedigree demonstrates autosomal dominant transmission with reduced penetrance of PAH, suggestive that additional genetic or environmental factors modify PAH development. Genetic testing and the discovery of rare genetic alterations in PAH during infancy and childhood may aid in identifying disease etiologies, guide therapeutic decisions, and ultimately identify novel therapeutic targets. Moreover, CAV1 genetics implicate variable expressivity and incomplete penetrance for HPAH and underscores the utility of predictive genetic testing for unaffected family members no matter their age.

Biological and clinical manifestations of Huntington’s disease in gene carriers very far from predicted onset

Introduction

Crucial to the future success of treatments in Huntington’s disease is identifying a timepoint where there is a measurable biomarker of early neurodegeneration without detectable changes in clinical function. By performing deep phenotyping in premanifest gene carriers (preHD) further from predicted onset than previously studied, we aimed to identify this timepoint and the best measures for efficacy endpoints in future therapeutic trials.

Methods

We recruited 64 young adult preHD, approximately 24 years from predicted clinical onset, and 67 matched controls. All participants underwent detailed cognitive and neuropsychiatric assessments, multi-modal imaging and collection of blood and cerebrospinal fluid (CSF).

Results

We found no significant evidence of cognitive or psychiatric impairment in preHD (minimum q>0.22). The PreHD cohort had smaller putamen volumes (q=0.03), but this was not related to predicted years to onset. There were no group differences in other brain imaging measures (q>0.16). CSF and plasma neurofilament light (NfL) (q<0.0001 and q=0.01) and YKL-40 (q=0.03) were elevated in preHD.

Conclusion

With normal brain function but with sensitive measures of neurodegeneration starting to rise, this stage of preHD may represent an optimal time to initiate future disease-modifying prevention treatments. CSF NfL appears more sensitive at this time than plasma NfL to monitor treatment response.

p.d.zeun@gmail.com

Maternal serum fructosamine levels and stillbirth: a case-control study of the Stillbirth Collaborative Research Network

OBJECTIVE

To evaluate the association between maternal fructosamine levels at the time of delivery and stillbirth.

DESIGN

Secondary analysis of a case-control study.

SETTING

Multicentre study of five geographic catchment areas in the USA.

POPULATION

All singleton stillbirths with known diabetes status and fructosamine measurement, and representative live birth controls.

MAIN OUTCOME MEASURES

Fructosamine levels in stillbirths and live births among groups were adjusted for potential confounding factors, including diabetes. Optimal thresholds of fructosamine to discriminate stillbirth and live birth.

RESULTS

A total of 529 women with a stillbirth and 1499 women with a live birth were included in the analysis. Mean fructosamine levels were significantly higher in women with a stillbirth than in women with a live birth after adjustment (177 ± 3.05 versus 165 ± 2.89 μmol/L, P < 0.001). The difference in fructosamine levels between stillbirths and live births was greater among women with diabetes (194 ± 8.54 versus 162 ± 3.21 μmol/L), compared with women without diabetes (171 ± 2.50 versus 162 ± 2.56 μmol/L). The area under the curve (AUC) for fructosamine level and stillbirth was 0.634 (0.605-0.663) overall, 0.713 (0.624-0.802) with diabetes and 0.625 (0.595-0.656) with no diabetes.

CONCLUSIONS

Maternal fructosamine levels at the time of delivery were higher in women with stillbirth compared with women with live birth. Differences were substantial in women with diabetes, suggesting a potential benefit of glycaemic control in women with diabetes during pregnancy. The small differences noted in women without diabetes are not likely to justify routine screening in all cases of stillbirth.

TWEETABLE ABSTRACT

Maternal serum fructosamine levels are higher in women with stillbirth than in women with live birth, especially in women with diabetes.

OP0151-PARE WORK IMPACTS EXPERIENCED BY YOUNGER PEOPLE WITH ARTHRITIS: A SYSTEMATIC REVIEW

Background:

On a global scale, it is estimated that adults in their peak income-earning years are disproportionately impacted by arthritis (1). Younger adults with arthritis are less likely to be employed and are more likely to face productivity challenges at work when compared to healthy similar-aged peers (2). The work-related impacts of arthritis on younger adults remain largely unexplored and are rarely considered in routine clinical care for arthritis.

Objectives:

To systematically identify, appraise and synthesise the available evidence on work impacts experienced by individuals aged 16-50 years with arthritis.

Methods:

Eligible studies from 2000 - 2020 were identified in OVID Medline, PsycINFO, Embase, and CINAHL databases using a comprehensive search strategy. Quantitative and qualitative studies containing self-reported data on the work impacts of arthritis on younger people were included. Quality assessment was undertaken using validated quality appraisal tools (3).

Results:

From a yield of 300 studies, 35 were included in the review. After quality assessment and exclusion of the lowest-ranked studies, 28 studies (17 quantitative, 11 qualitative) were analysed. Work outcomes data were organised into five themes (1-3 for quantitative outcomes, 4-5 for qualitative outcomes): (1) the impacts of arthritis on work productivity; (2) the impacts of arthritis on work participation; (3) other arthritis attributable workplace challenges; (4) barriers to work participation associated with arthritis, and (5) enablers to work participation associated with arthritis. For quantitative themes, arthritis was strongly associated with other workplace challenges: scores on the Workplace Activity Limitations Scale ranged from 5.9 (moderate workplace difficulty) to 9.8 (considerable workplace difficulty); and work disability relative to the healthy population (prevalence ranging from 6% - 80%). For qualitative themes, barriers to work participation included lack of workplace support; enablers included workplace support and intrinsic motivation to work.

Conclusion:

Arthritis is associated with poorer work outcomes for younger people relative to healthy peers. The available evidence was heterogeneous across studies. Additional research focusing solely on the unique workplace needs of younger population groups is required. This would inform the development of tailored intervention or workplace support strategies to maximise productive working years.

References:

[1]European League Against Rheumatism. Horizon 2020 Framework Programme: EULAR’s positions and recommendations. EULAR 2011.

[2]Jetha A. (2015). The impact of arthritis on the early employment experiences of young adults: A literature review. Disabil Health J. 8(3) 317-324.

[3]Joanna Briggs Institute. Critical Appraisal Tools. The University of Adelaide 2019.

Disclosure of Interests:

None declared

Advances in targeted alpha therapy for prostate cancer

Amongst therapeutic radiopharmaceuticals, targeted alpha therapy (TαT) can deliver potent and local radiation selectively to cancer cells as well as the tumor microenvironment and thereby control cancer while minimizing toxicity. In this review, we discuss the history, progress, and future potential of TαT in the treatment of prostate cancer, including dosimetry-individualized treatment planning, combinations with small-molecule therapies, and conjugation to molecules directed against antigens expressed by prostate cancer cells, such as prostate-specific membrane antigen (PSMA) or components of the tumor microenvironment. A clinical proof of concept that TαT is efficacious in treating bone-metastatic castration-resistant prostate cancer has been demonstrated by radium-223 via improved overall survival and long-term safety/tolerability in the phase III ALSYMPCA trial. Dosimetry calculation and pharmacokinetic measurements of TαT provide the potential for optimization and individualized treatment planning for a precision medicine-based cancer management paradigm. The ability to combine TαTs with other agents, including chemotherapy, androgen receptor-targeting agents, DNA repair inhibitors, and immuno-oncology agents, is under investigation. Currently, TαTs that specifically target prostate cancer cells expressing PSMA represents a promising therapeutic approach. Both PSMA-targeted actinium-225 and thorium-227 conjugates are under investigation. The described clinical benefit, safety and tolerability of radium-223 and the recent progress in TαT trial development suggest that TαT occupies an important new role in prostate cancer treatment. Ongoing studies with newer dosimetry methods, PSMA targeting, and novel approaches to combination therapies should expand the utility of TαT in prostate cancer treatment.

An optimized assay for detecting Encephalitozoon intestinalis and Enterocytozoon bieneusi in dairy calf feces using polymerase chain reaction technology

The purpose of this study was to optimize primary and nested polymerase chain reaction (PCR) assays for detecting the microsporidia Encephalitozoon intestinalis and Enterocytozoon bieneusi in fecal samples from dairy calves. PCR for these microsporidia were compared to immunofluorescence assays (IFA) based on commercially available monoclonal antibodies specific for outer wall proteins of Enc. intestinalis or Ent. bieneusi. Fecal samples were collected from 15 dairy calves and processed by molecular sieving followed by salt floatation to recover Enc. intestinalis and Ent. bieneusi spores. An aliquot of the final supernatant was applied to glass slides for IFA testing; another aliquot was extracted for total DNA using a QIAamp Stool Mini-Kit for primary and nested Enc. intestinalis- and Ent. bieneusi-specific PCR analysis. Internal standards were generated for both Enc. intestinalis and Ent. bieneusi PCR assays to control for false negative reactions due to the presence of inhibitors commonly found in fecal samples. Using the commercial MicrosporIFA (Waterborne, Inc.) as the gold standard, the optimized Enc. intestinalis PCR method provided 85.7% sensitivity and 100% specificity with a kappa value = 0.865. Likewise, using the commercial BienusiGlo IFA (Waterborne, Inc.) as the gold standard, the optimized Ent. bieneusi PCR method provided 83.3% sensitivity and 100% specificity with a kappa value = 0.857. Sequencing of amplicons from both PCR assays confirmed the presence of Enc. intestinalis or Ent. bieneusi. In conclusion, our optimized assays for recovering and detecting Enc. intestinalis or Ent. bieneusi in feces from dairy calves provides a valuable alternative to traditional IFA methods that require expertise to identify extremely small microsporidia spores (~ 2.0 µm). Our assays also improve upon existing molecular detection techniques for these microsporidia by incorporating an internal standard to control for false negative reactions.

Multiple Sites of Impingement of a Tracheal Tube as it is Advanced over a Fibreoptic Bronchoscope or Tracheal Tube Introducer in Anaesthetized, Paralysed Patients

Impingement of the tracheal tube on upper airway structures occurs commonly during advancement over a fibreoptic bronchoscope or introducer. In this descriptive study a fibrescope was used to assess the site and mechanism of tracheal tube impingement during advancement over a variety of fibreoptic bronchoscopes and introducers during orotracheal intubation in anaesthetized adults. The effect of the 90° counterclockwise rotation manoeuvre in overcoming impingement was also assessed. We recorded impingement at the right arytenoid, left arytenoid, epiglottis, interarytenoid tissue and the left pyriform fossa. Our study found a wider range of sites at which impingement may occur than in previous studies. We also found that when 90° counterclockwise rotation of the tip of the tracheal tube was achieved, the impingement was reliably overcome.

Increased detection of carbapenemase-producing Enterobacteriaceae on post-clean sampling of a burns unit's wet surfaces

Wet surface biofilms are a potential reservoir for multidrug-resistant Gram-negative organisms, including carbapenemase-producing Enterobacteriaceae (CPE). Recognition of environmental sources is important in reducing secondary patient transmission. We report the increased detection of blaIMP-4⁺ CPE in environmental samples from floor drains in burns unit shower rooms, when collected following cleaning as compared to pre-cleaning. We propose that disruption of biofilms during cleaning may account for the increased detection of multi-resistant organisms. The results highlight the role of the wet environment as an under-recognized potential source of CPE transmission. Environmental screening focusing on pre-cleaning samples alone will likely underestimate environmental contamination.

Missing Evidence: Exploring Unpublished Trials in Victoria, Australia

Background: Clinical trial registries were established to improve the transparency and completeness of clinical trial reporting and a number of policies have been introduced to encourage or mandate their use. While prospective trial registration has been endorsed in Australia, there is currently no legal requirement for researchers to register or communicate findings from clinical trials. There has also been, to the best of our knowledge, no analysis previously undertaken on publication rates for clinical trials performed in Australia. Aim: We aimed to determine the proportion of clinical trials that remain 'unpublished' in Victoria, Australia´s second most populous state, between 2009 and 2013. Methods: We used data reported to Cancer Council Victoria's Cancer Trials Management Scheme (CTMS) between 2009 and 2013, to identify trials that had recruited a new patient or recorded any follow-up patient activity in the specified time period. Using this data, we conducted a systematic search of ClinicalTrials.gov , the Australia and New Zealand Clinical Trials Registry (ANZCTR), PubMed and Google for records of the trial. Trial registration numbers, acronyms and scientific titles were used as primary search terms. Results were characterized by type of publication (i.e., whether it was an accredited scientific paper or other) and source location. Results: Of the trials reported to the CTMS between 2009 and 2013, 777 trials were included in this investigation; the majority (58.8%) were randomized controlled trials (RCTs). Compared with previously published findings, communication of trial results in this study was high; 70% of trials published results in an accredited scientific journal and a further 10% in alternate form, such as a conference abstract or media release. Publication rates were higher for trials with a commercial sponsor (85%) compared with trials sponsored by a cooperative group (77%). Nearly 8% of trials in this study had not been registered on an international clinical trials register. Only 39% of unregistered trials had published results. Of the registered trials, those registered on ClinicalTrials.gov were more likely to be published (86%) compared with trials listed on ANZCTR (68%). Between 2009 and 2013 , 8% of trials registered on ClinicalTrials.gov , in our data set, were terminated; 70% of these trials published results. Conclusion: Although the rate at which clinical trial findings were published in Victoria was higher in this investigation compared with equivalent overseas data, trials registered on ClinicalTrials.gov were more likely to publish results than unregistered trials or trials registered on ANZCTR. This suggests a potential need for trial registration and publication guidelines in Australia, similar to that of the United States where the requirements and procedures for submitting registration and summary result information for clinical trials on ClinicalTrials.gov have been compulsory for the last decade.

An exploratory analysis of alkaline phosphatase, lactate dehydrogenase, and prostate-specific antigen dynamics in the phase 3 ALSYMPCA trial with radium-223

Background

Baseline clinical variables are prognostic for overall survival (OS) in patients with castration-resistant prostate cancer (CRPC). Their prognostic and predictive value with agents targeting bone metastases, such as radium-223, is not established.

Patients and methods

The radium-223 ALSYMPCA trial enrolled patients with CRPC and symptomatic bone metastases. Prognostic potential of baseline variables was assessed using Cox models. Percentage changes in biomarker levels from baseline were evaluated during the trial period; changes from baseline to week 12 were evaluated for association with OS and surrogacy.

Results

Eastern Cooperative Oncology Group performance status, total alkaline phosphatase (tALP), lactate dehydrogenase (LDH), and prostate-specific antigen (PSA) at baseline were associated with OS (P ≤ 0.0003) in the intent-to-treat population (radium-223, N = 614; placebo, N = 307). tALP declined from baseline within 4 weeks after beginning radium-223, by week 12 declining in 87% of radium-223 and 23% of placebo patients (P < 0.001). LDH declined in 51% and 34% (P = 0.003), whereas PSA declined in 27% and 14% (P = 0.160). Mean tALP change from baseline was 32.2% decrease with radium-223 and 37.2% increase with placebo. Radium-223 patients with tALP decline from baseline to week 12 (confirmed ≥3 weeks from week 12) had 55% lower risk of death (hazard ratio = 0.45; 95% CI 0.34-0.61) versus those with no confirmed tALP decline. Proportional treatment effect (PTE) values for tALP, LDH, and PSA changes from baseline at week 12 as OS surrogate markers were 0.34 (95% CI: 0-0.746), 0.07 (95% CI: 0-0.211), and 0 (95% CI: 0-0.082), respectively.

Conclusions

Significant tALP declines (versus placebo) occurred as early as 4 weeks after beginning radium-223 therapy. tALP or LDH declines at 12 weeks correlated with longer OS, but did not meet statistical surrogacy requirements. Dynamic changes in tALP and LDH during radium-223 treatments may be useful to monitor, but do not serve as surrogates for survival.

The relationship between exclusion from school and mental health: a secondary analysis of the British Child and Adolescent Mental Health Surveys 2004 and 2007

BACKGROUND

Children with poor mental health often struggle at school. The relationship between childhood psychiatric disorder and exclusion from school has not been frequently studied, but both are associated with poor adult outcomes. We undertook a secondary analysis of the British Child and Adolescent Mental Health Surveys from 2004 and its follow-up in 2007 to explore the relationship between exclusion from school and psychopathology. We predicted poorer mental health among those excluded.

METHOD

Psychopathology was measured using the Strengths and Difficulties Questionnaire, while psychiatric disorder was assessed using the Development and Well-Being Assessment and applying Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM IV) criteria. Exclusion from school and socio-demographic characteristics were reported by parents. Multi-variable regression models were used to examine the impact of individual factors on exclusion from school or psychological distress.

RESULTS

Exclusion from school was commoner among boys, secondary school pupils and those living in socio-economically deprived circumstances. Poor general health and learning disability among children and poor parental mental health were also associated with exclusion. There were consistently high levels of psychological distress among those who had experienced exclusion at baseline and follow-up.

CONCLUSIONS

We detected a bi-directional association between psychological distress and exclusion. Efforts to identify and support children who struggle with school may therefore prevent both future exclusion and future psychiatric disorder.

Which children and young people are excluded from school? Findings from a large British birth cohort study, the Avon Longitudinal Study of Parents and Children (ALSPAC)

BACKGROUND

Exclusion from school is increasingly recognized as pertinent to child health. National educational data reveal that boys, children who are looked-after, living in poverty, have special educational needs, or from certain ethnic minorities, are disproportionately excluded from school. As population-based data on the wider characteristics of excluded children are scarce, we aimed to describe predictors of school exclusion in the Avon Longitudinal Study of Parents and Children.

METHOD

Avon Longitudinal Study of Parents and Children, a prospective U.K. population-based birth cohort study, collected parent reports of permanent school exclusions by 8 years and parent and self-reports of permanent and fixed-term exclusions in the preceding 12 months at 16 years. Potential risk factors were examined for associations with exclusion using logistic regression, with a focus on child mental health and neurodevelopment.

RESULTS

Analyses were based on all available data on 53/8,245 (0.6%) pupils excluded from school by 8 years and 390/4,482 (8.7%) at 16 years. Key factors associated with exclusion at both time points included male gender, lower socio-economic status, maternal psychopathology, mental health and behavioural difficulties, psychiatric disorder, social communication difficulties, language difficulties, antisocial activities, bullying/being bulled, lower parental engagement with education, low school engagement, poor relationship with teacher, low educational attainment, and special educational needs (all p < .05).

CONCLUSION

Exclusion from school was associated with child, family and school-related factors identifiable at, or prior to, primary school age. Child health professionals have an important role in the holistic, multidisciplinary assessment of children who are at risk of exclusion from school. Mental health and neurodevelopmental difficulties should be recognized and supported, to improve the health and educational outcomes among this vulnerable group.

Review article: dose optimisation of infliximab for acute severe ulcerative colitis

BACKGROUND

Although optimal medical management of acute severe ulcerative colitis (UC) is ill-defined, infliximab has become a standard of care. Accumulating evidence suggests an increased rate of infliximab clearance in patients with acute severe UC and a reduced colectomy rate with an intensified infliximab induction regimen.

AIM

To assess the strength of the current evidence for the relationship between infliximab pharmacokinetics, dosing strategies and disease behaviour in patients with acute severe UC.

METHODS

We systematically searched MEDLINE and conference proceedings from 2000 to 2016 for relevant articles describing the pharmacokinetics of infliximab in acute severe UC and/or infliximab dose intensification strategies in acute severe UC. Eligible articles described randomised controlled trials, and cohort, cross-sectional, and case-controlled studies.

RESULTS

Of 400 citations identified, 76 studies were eligible. Increased infliximab clearance occurs in patients with acute severe UC, and is driven by the total inflammatory burden and leakage of drug into the colonic lumen. Several cohort studies suggest that infliximab dose intensification is beneficial to at least 50% of acute severe UC patients and the results of case-controlled studies indicate that an intensified infliximab dosing regimen with 1-2 additional infusions in the first 3 weeks of treatment could reduce the early (3-month) colectomy rate by up to 80%, although these data require prospective validation.

CONCLUSIONS

Uncontrolled studies suggest a benefit for infliximab dose optimisation in patients with acute severe UC. A randomised controlled trial in acute severe UC patients comparing a personalised infliximab dose-optimisation strategy with conventional dosing is a research priority.

Assessment of the interaction of hyperbaric N2, CO2, and O2 on psychomotor performance in divers

Diving narcosis results from the complex interaction of gases, activities, and environmental conditions. We hypothesized that these interactions could be separated into their component parts. Where previous studies have tested single cognitive tasks sequentially, we varied inspired partial pressures of CO₂, N₂, and O₂ in immersed, exercising subjects while assessing multitasking performance with the Multi-Attribute Task Battery II (MATB-II) flight simulator. Cognitive performance was tested under 20 conditions of gas partial pressure and exercise in 42 male subjects meeting U.S. Navy age and fitness profiles. Inspired nitrogen (N₂) and oxygen (O₂) partial pressures were 0, 4.5, and 5.6 ATA and 0.21, 1.0, and 1.22 ATA, respectively, at rest and during 100-W immersed exercise with and without 0.075-ATA CO₂ Linear regression modeled the association of gas partial pressure with task performance while controlling for exercise, hypercapnic ventilatory response, dive training, video game frequency, and age. Subjects served as their own controls. Impairment of memory, attention, and planning, but not motor tasks, was associated with N₂ partial pressures >4.5 ATA. Sea level O₂ at 0.925 ATA partially rescued motor and memory reaction time impaired by 0.075-ATA CO₂; however, at hyperbaric pressures an unexpectedly strong interaction between CO₂, N₂, and exercise caused incapacitating narcosis with amnesia, which was augmented by O₂ Perception of narcosis was not correlated with actual scores. The relative contributions of factors associated with diving narcosis will be useful to predict the effects of gas mixtures and exercise conditions on the cognitive performance of divers. The O₂ effects are consistent with O₂ narcosis or enhanced O₂ toxicity.