Cognitive decrements in 1991 Gulf War veterans: associations with Gulf War illness and neurotoxicant exposures in the Boston Biorepository, Recruitment, and Integrative Network (BBRAIN) cohorts

BACKGROUND

During deployment, veterans of the 1991 Gulf War (GW) were exposed to multiple war-related toxicants. Roughly a third of these veterans continue to exhibit neurotoxicant induced symptoms of Gulf War Illness (GWI), a multi-faceted condition that includes fatigue, pain and cognitive decrements. When studied empirically, both deployed veterans with exposures and those who meet the criteria for GWI are more likely to show deficits in the area of neuropsychological functioning. Although studies have shown cognitive impairments in small sample sizes, it is necessary to revisit these findings with larger samples and newer cohorts to see if other areas of deficit emerge with more power to detect such differences. A group of researchers and clinicians with expertise in the area of GWI have identified common data elements (CDE) for use in research samples to compare data sets. At the same time, a subgroup of researchers created a new repository to share these cognitive data and biospecimens within the GWI research community.

METHODS

The present study aimed to compare cognitive measures of attention, executive functioning, and verbal memory in a large sample of GWI cases and healthy GW veteran controls using neuropsychological tests recommended in the CDEs. We additionally subdivided samples based on the specific neurotoxicant exposures related to cognitive deficits and compared exposed versus non-exposed veterans regardless of case criteria status. The total sample utilized cognitive testing outcomes from the newly collated Boston, Biorepository, Recruitment, and Integrative Network (BBRAIN) for GWI.

RESULTS

Participants included 411 GW veterans, 312 GWI (cases) and 99 healthy veterans (controls). Veterans with GWI showed significantly poorer attention, executive functioning, learning, and short-and-long term verbal memory than those without GWI. Further, GW veterans with exposures to acetylcholinesterase inhibiting pesticides and nerve gas agents, had worse performance on executive function tasks. Veterans with exposure to oil well fires had worse performance on verbal memory and those with pyridostigmine bromide anti-nerve gas pill exposures had better verbal memory and worse performance on an attention task compared to unexposed veterans.

CONCLUSIONS

This study replicates prior results regarding the utility of the currently recommended CDEs in determining impairments in cognitive functioning in veterans with GWI in a new widely-available repository cohort and provides further evidence of cognitive decrements in GW veterans related to war-related neurotoxicant exposures.

Genetic association between the APOE ε4 allele, toxicant exposures and Gulf war illness diagnosis

INTRODUCTION

Exposure to nerve agents, pyridostigmine bromide (PB), pesticides, and oil-well fires during the 1991 Gulf War (GW) are major contributors to the etiology of Gulf War Illness (GWI). Since the apolipoprotein E (APOE) ε4 allele is associated with the risk of cognitive decline with age, particularly in the presence of environmental exposures, and cognitive impairment is one of the most common symptoms experienced by veterans with GWI, we examined whether the ε4 allele was associated with GWI.

METHODS

Using a case-control design, we obtained data on APOE genotypes, demographics, and self-reported GW exposures and symptoms that were deposited in the Boston Biorepository and Integrative Network (BBRAIN) for veterans diagnosed with GWI (n = 220) and healthy GW control veterans (n = 131). Diagnosis of GWI was performed using the Kansas and/or Center for Disease Control (CDC) criteria.

RESULTS

Age- and sex-adjusted analyses showed a significantly higher odds ratio for meeting the GWI case criteria in the presence of the ε4 allele (Odds ratio [OR] = 1.84, 95% confidence interval [CI = 1.07-3.15], p ≤ 0.05) and with two copies of the ε4 allele (OR = 1.99, 95% CI [1.23-3.21], p ≤ 0.01). Combined exposure to pesticides and PB pills (OR = 4.10 [2.12-7.91], p ≤ 0.05) as well as chemical alarms and PB pills (OR = 3.30 [1.56-6.97] p ≤ 0.05) during the war were also associated with a higher odds ratio for meeting GWI case criteria. There was also an interaction between the ε4 allele and exposure to oil well fires (OR = 2.46, 95% CI [1.07-5.62], p ≤ 0.05) among those who met the GWI case criteria.

CONCLUSION

These findings suggest that the presence of the ε4 allele was associated with meeting the GWI case criteria. Gulf War veterans who reported exposure to oil well fires and have an ε4 allele were more likely to meet GWI case criteria. Long-term surveillance of veterans with GWI, particularly those with oil well fire exposure, is required to better assess the future risk of cognitive decline among this vulnerable population.

A67 RISK FACTORS ASSOCIATED WITH CRITICAL CARE AFTER INPATIENT GASTROINTESTINAL ENDOSCOPY: A 5-YEAR TERTIARY HOSPITAL STUDY

Background

A subset of hospitalized patients will require critical care after their gastrointestinal endoscopy (GIE) and predicting which patients are at high risk of requiring critical care remains an important challenge.

Purpose

To identify protective and aggravating clinical risk factors associated with critical care involvement within 7 days of inpatient GIE in adults and to develop a tool that could assist in risk-stratifying patients at high risk of requiring critical care post-endoscopy.

Method

This was a single-centre retrospective case-control study of adult patients who underwent inpatient GIE while admitted to ward-level care at Toronto General Hospital from years 2015 to 2019. Cases were defined by inpatients who required critical care response team and/or critical care admission within 7 days of GIE, compared to control patients who did not require critical care throughout admission. Chart review and linked secondary sources were used with defined inclusion and exclusion criteria. Both univariate and multivariate analyses were performed comparing patient baseline, clinical history (including cardiovascular, respiratory, other co-morbidities) and endoscopy characteristics.

Result(s)

We identified a total of 275 patients with 302 endoscopies as cases and 2069 patient controls who satisfied inclusion criteria. Critical care involvement was most commonly due to cardiovascular-related complications (n=175, 58%) followed by respiratory complications (n=117, 39%). Amongst cases, death occurred in 9 (3%), 25 (9%) and 67 (22%) within 72 hours, 7 days and 30 days respectively post endoscopy. The strongest associations with critical care involvement within 7 days after GIE included a history of discharge from critical care (OR 2.29 CI 1.70-3.04) and/or recent mechanical ventilatory support (OR 2.27 CI 1.30-3.91) in the 30 days prior to endoscopy, having several co-morbidities involving major organ systems (elevated troponin OR 3.20 CI 2.26-4.52, cirrhosis OR 2.5 CI 1.80-3.46, renal dysfunction 2.09 CI 1.57-2.78) and patients admitted under surgical (OR 3.82 CI 2.54-5.71) or transplant services (OR 4.63 CI 2.94-7.26). The majority of adverse events among cases were not found to be complications directly related to GIE (64% unlikely, 20% possible, 9% probable, 7% definite). Patients with a history of pulmonary hypertension (OR 5.68 CI 0.53-60.70) and ASA score III/IV (OR 3.28 CI 1.01-10.73) had the highest odds of probable or definite endoscopy-related adverse events.

Conclusion(s)

This study is the largest to date to examine risk factors associated with critical care requirements post GIE in the tertiary care inpatient setting. The risk factors we have identified can be used to create a tool to determine which inpatients may benefit from anesthesia consultation and support during their endoscopic procedure.

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Disclosure of Interest

None Declared

Hydrogeochemical mineral exploration in deeply weathered terrains: An example from Mumbwa, Zambia

Locating mineral deposits in areas of thick or transported overburden is notoriously difficult. Post-mineral cover is prevalent in many parts of the globe and has led to prospective geological sequences being missed by traditional methods of exploration. Hydrogeochemistry is particularly applicable for the exploration of Iron Oxide Copper Gold (IOCG) deposits because, when compared to larger porphyry or sediment-hosted systems, IOCG deposits tend to be smaller and high-grade with a limited lateral footprint to intersect with grid-drilling; groundwater interactions and ion dispersion tend to produce a much larger anomaly target than regolith geochemistry alone and require fewer samples. As a case study, we examine the hydrogeochemistry of the Kitumba IOCG deposit, located in the Mumbwa district of west-central Zambia. We present physicochemical data (Eh, pH, TDS, conductivity), major and trace element concentrations, and isotopic compositions (δ⁹⁸Mo, ⁸⁷Sr/⁸⁶Sr, and δ⁶⁵Cu) from groundwaters interacting with the Kitumba deposit and surrounding prospects. A hydrogeochemical footprint of As, Mo, Fe, Mn, and Zn is dispersed from the deposit. Groundwater ⁸⁷Sr/⁸⁶Sr values (0.708832 to 0.731807) reflect the mixing in varying proportions of waters that have interacted with distinct lithological endmembers in the Mumbwa area, corresponding to a complicated tectonic and metamorphic history. We report fractionation of 1.34 to 1.60‰ (∆⁶⁵Cu_{groundwater - chalcopyrite}) between proximal groundwater and primary chalcopyrite, which we postulate may be related to the oxidative dissolution of primary sulfide minerals. The δ⁹⁸Mo₃₁₃₄ values of groundwaters proximal to known ore bodies are isotopically distinct (-1.08 ± 0.18‰ 2SE to 0.64 ± 0.08‰ 2 SE) from background aquifers (2.08 ± 0.12‰ 2SE). The trace element and isotopic hydrogeochemical patterns described in this study document water-rock and water-deposit interactions and demonstrate the potential of non-traditional stable isotopes to be employed in district-scale reduction of exploration ground and vectoring towards undisturbed ore deposits similar to Kitumba.

Boston biorepository, recruitment and integrative network (BBRAIN): A resource for the Gulf War Illness scientific community

AIMS

Gulf War Illness (GWI), a chronic debilitating disorder characterized by fatigue, joint pain, cognitive, gastrointestinal, respiratory, and skin problems, is currently diagnosed by self-reported symptoms. The Boston Biorepository, Recruitment, and Integrative Network (BBRAIN) is the collaborative effort of expert Gulf War Illness (GWI) researchers who are creating objective diagnostic and pathobiological markers and recommend common data elements for GWI research.

MAIN METHODS

BBRAIN is recruiting 300 GWI cases and 200 GW veteran controls for the prospective study. Key data and biological samples from prior GWI studies are being merged and combined into retrospective datasets. They will be made available for data mining by the BBRAIN network and the GWI research community. Prospective questionnaire data include general health and chronic symptoms, demographics, measures of pain, fatigue, medical conditions, deployment and exposure histories. Available repository biospecimens include blood, plasma, serum, saliva, stool, urine, human induced pluripotent stem cells and cerebrospinal fluid.

KEY FINDINGS

To date, multiple datasets have been merged and combined from 15 participating study sites. These data and samples have been collated and an online request form for repository requests as well as recommended common data elements have been created. Data and biospecimen sample requests are reviewed by the BBRAIN steering committee members for approval as they are received.

SIGNIFICANCE

The BBRAIN repository network serves as a much needed resource for GWI researchers to utilize for identification and validation of objective diagnostic and pathobiological markers of the illness.

Seven-year retrospective study understanding the latent TB infection treatment cascade of care among adults in a low incidence country

Background

Prevention of TB is paramount to achieving elimination targets as recommended by the World Health Organization’s action framework for low incidence countries striving to eliminate TB. Although the rates of TB in Canada are low, understanding the latent TB infection (LTBI) cascade is paramount to identifying gaps in care and treatment barriers, thereby increasing the effectiveness of preventive strategies. The purpose of this study was to examine the LTBI cascade of care and identify barriers to treatment completion in adults referred from primary care to a regional tertiary care TB clinic in Ottawa, Canada.

Methods

Electronic medical records between January 2010 and December 2016 were reviewed retrospectively and an LTBI cascade of care was constructed from The Ottawa Hospital TB clinic and surrounding primary care clinics. A cohort of 2207 patients with untreated LTBI was used to ascertain the associations between demographic and clinical factors for both treatment non-initiation and non-completion using log-binomial univariable and multivariable regression models.

Results

Of 2207 patients with untreated LTBI who were seen in the clinic during the study period, 1771 (80.2%) were offered treatment, 1203 (67.9% of those offered) started treatment, and 795 (66.1% of those started) completed treatment. In multivariable analysis, non-initiation of treatment was associated with older age (adjusted risk ratio [aRR] 1.06 per 5-year increase, 95% CI: 1.03–1.08) and female gender (aRR 1.28, 95% CI: 1.11–1.47). Non completion of treatment was associated with referral from the TB Clinic back to the primary care team following initial consult (aRR 1.62, 95% CI: 1.35–1.94) and treatment with the standard of 9 months of Isoniazid (9H) compared to 4 months of Rifampin (4R) (aRR 1.45, 95% CI:1.20–1.74).

Conclusions

LTBI treatment completion was significantly decreased among patients who were referred back to primary care from the TB clinic. The 4R regimen resulted in more people completing LTBI treatment compared to 9H in keeping with a recently published RCT. Improved education, communication, and collaboration between tertiary care TB clinics and primary care teams may improve treatment completion rates and address the TB burden in low incidence communities in Canada.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10733-9.

A-73 Does Trauma Type Influence the Symptom Profile in Feigned Posttraumatic Stress Disorder (PTSD)?

Objective

Posttraumatic Stress Disorder (PTSD) is vulnerable to feigning. This presents a major challenge for clinicians who must differentiate between genuine and feigned presentations. Past studies have shown that in genuine PTSD the symptom profiles varies as a function of trauma type. It is not yet clear if this variation also occurs for feigned PTSD.

Method

Sixty participants were each randomly assigned to one of two experimental conditions. Both conditions provided: i) coaching about PTSD and ii) instructions to feign PTSD as if for financial gain. The trigger event in the conditions was either sexual assault (SA) or a motor vehicle collision (MVC), and it was manipulated in a written vignette. Outcomes were assessed via standardized measures for PTSD symptoms (PCL-5) and profile invalidity (Structured Inventory of Malingered Symptomology [SIMS]).

Results

All participants exceeded the PCL-5 and SIMS cut scores, indicating a plausible PTSD symptom profile with over-reported (detectable) symptoms. However, there were no statistically significant group differences on the PCL-5 or SIMS at the overall, subscale, or profile levels (all p’s > 0.05).

Conclusions

Unlike genuine PTSD, in simulated PTSD the symptom profile did not differ by trauma type. The feigned performance was detected on the SIMS which could recommend this test, and this requires further investigation. If understanding of the genuine PTSD profiles for different trauma types is further developed and if our result is replicated, the future use of profile-analyses could assist clinicians when evaluating feigned PTSD.

Is incident rheumatoid arthritis interstitial lung disease associated with methotrexate treatment? Results from a multivariate analysis in the ERAS and ERAN inception cohorts

OBJECTIVES

To assess predictive factors for rheumatoid arthritis interstitial lung disease (RA-ILD) in two early rheumatoid arthritis (RA) inception cohorts with a focus on methotrexate (MTX) exposure.

DESIGN

Multicentre prospective early RA inception cohort studies; the early RA study (ERAS) and the early RA network (ERAN).

SETTING

Secondary care, ERAS nine centres, ERAN 23 centres in England, Wales and Ireland.

PARTICIPANTS

Patients with new diagnosis of RA, n=2701. Standardised data including demographics, drug therapies and clinical outcomes including the presence of RA-ILD were collected at baseline, within 3-6 months, at 12 months and annually thereafter.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome was the association of MTX exposure on RA-ILD diagnosis. Secondary outcomes were the association of demographic, comorbid and RA-specific factors on RA-ILD diagnosis and the association of MTX exposure on time to RA-ILD diagnosis.

RESULTS

Of 92 eligible ILD cases, 39 occurred in 1578 (2.5%) MTX exposed and 53 in 1114 (4.8%) non-MTX exposed cases. The primary analysis of RA-ILD cases only developing after any conventional synthetic disease-modifying antirheumatic drug treatment (n=67) showed MTX exposure not to be associated with incident RA-ILD (OR 0.85, 95% CI 0.49 to 1.49, p=0.578) and a non-significant trend for delayed ILD diagnosis (OR 0.54, 95% CI 0.28 to 1.06, p=0.072). In an extended analysis including RA-ILD cases present at RA diagnosis (n=92), MTX exposure was associated with a significantly reduced risk of incident RA-ILD (OR 0.48, 95% CI 0.3 to 0.79, p=0.004) and longer time to ILD diagnosis (OR 0.41, 95% CI 0.23 to 0.75, p=0.004). Other independent baseline associations with incident RA-ILD were higher age of RA onset, ever smoking, male gender, rheumatoid nodules and longer time from first RA symptom to first outpatient visit.

CONCLUSIONS

MTX treatment was not associated with an increased risk of RA-ILD diagnosis. On the contrary, evidence suggested that MTX may delay the onset of ILD.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Accuracy of internet images of ligamentous knee injuries

BACKGROUND

The internet is an easily accessible resource for both providers and patients. Despite this, the internet is not peer reviewed, leaving searches subject to inaccuracies, especially with regards to medical information. The purpose of this study was to review internet images of anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL) tears using two popular search engines: Google and Bing.

METHODS

A search query was performed on both Google and Bing for the following terms: 'ACL tear', 'PCL tear', 'MCL tear' and 'LCL tear'. The first 100 images of each individual search were analyzed by three independent orthopedists.

RESULTS

The inter-rater reliability was very good for PCL tear on Bing (Cronbach's alpha = 0.89) and excellent (Cronbach's alpha > 0.9) for the remainder of the search queries. When comparing Google to Bing, the only significant difference occurred in the ACL group, with Bing returning a significantly greater number of correct images 60%, 95% CI: 53.2 - 66.7%) compared to Google (45% correct, 95% CI: 38.1-51.8%), p = 0.034. With regards to the other ligaments Bing was more accurate than Google for PCL (39% versus 38%), and LCL (32% to 30%). Both sites were 48% accurate for MCL tear.

CONCLUSION

Ultimately, our study revealed that physicians should take an active role in making high quality, easy to understand medical resources and anatomic diagrams available to their patients to avoid confusion and enhance understanding when querying the internet for additional information regarding their condition.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Quantitative Raman microspectroscopy for water permeability parameters at a droplet interface bilayer

Using confocal Raman microspectroscopy, we derive parameters for bilayer water transport across an isolated nanoliter aqueous droplet pair.

Arthroscopic Bankart Repair for the Management of Anterior Shoulder Instability: Indications and Outcomes

PURPOSE OF REVIEW

Arthroscopic Bankart repair is commonly utilized for shoulder stabilization in patients with anterior shoulder instability with minimum glenoid bone loss. The purpose of this review is to provide the indications, surgical technique, complications, and recent outcomes in arthroscopic Bankart repair for shoulder instability.

RECENT FINDINGS

Improvements in arthroscopic techniques have led to better patient outcomes, as well as an improved understanding of the pathoanatomy of instability. More recent studies have shown that one of the potential failures of primary arthroscopic repair may be due to unaddressed bone loss. This underscores the importance of evaluating glenoid bone loss and proper patient selection for this procedure to ensure successful outcome. When indicated, arthroscopic stabilization is the treatment of choice for many surgeons due to its lower morbidity and low overall complication rate. Future work must focus on longer-term outcomes in patients undergoing arthroscopic Bankart repair, as well as the clinical outcomes of new fixation techniques, augmentation techniques, and the effect of glenoid bone loss in outcome.

Systematic scoping review of patients' perceived needs of health services for osteoporosis

Health service planners, administrators and providers need to understand the patients' perspective of health services related to osteoporosis to optimise health outcomes. The aims of this study were to systematically identify and review the literature regarding patients' perceived health service needs relating to osteoporosis and osteopenia. A systematic scoping review was performed of publications in MEDLINE, EMBASE, CINAHL and PsycINFO (1990-2016). Descriptive data regarding study design and methodology were extracted and risk of bias assessed. Aggregates of patients' perceived needs of osteoporosis health services were categorised. Thirty-three studies (19 quantitative and 14 qualitative) from 1027 were relevant. The following areas of perceived need emerged: (1) patients sought healthcare from doctors to obtain information and initiate management. They were dissatisfied with poor communication, lack of time and poor continuity of care. (2) Patients perceived a role for osteoporosis pharmacotherapy but were concerned about medication administration and adverse effects. (3) Patients believed that exercise and vitamin supplementation were important, but there is a lack of data examining the needs for other non-pharmacological measures such as smoking cessation and alcohol. (4) Patients wanted diagnostic evaluation and ongoing surveillance of their bone health. This review identified patients' needs for better communication with their healthcare providers. It also showed that a number of important cornerstones of therapy for osteoporosis, such as pharmacotherapy and exercise, are identified as important by patients, as well as ongoing surveillance of bone health. Understanding patients' perceived needs and aligning them with responsive and evidence-informed service models are likely to optimise patient outcomes.

Simultaneous 68Ga DOTATATE Positron Emission Tomography/Magnetic Resonance Imaging in Meningioma Target Contouring: Feasibility and Impact Upon Interobserver Variability Versus Positron Emission Tomography/Computed Tomography and Computed Tomography/Magnetic Resonance Imaging

AIMS

The increasing use of highly conformal radiation techniques to treat meningioma confers a greater need for accurate targeting. Several groups have shown that positron emission tomography/computed tomography (PET/CT) information alters meningioma targets contoured by single observers, but whether this translates into improved accuracy has not been defined. As magnetic resonance imaging (MRI) is the cornerstone of meningioma target contouring, simultaneous PET/MRI may be superior to PET/CT. We assessed whether ⁶⁸Ga DOTATATE PET imaging (from PET/CT and PET/MRI) reduced interobserver variability (IOV) in meningioma target volume contouring.

MATERIALS AND METHODS

Ten patients with meningioma underwent simultaneous ⁶⁸Ga DOTATATE PET/MRI followed by PET/CT. They were selected as it was anticipated that target volume definition in their cases would be particularly challenging. Three radiation oncologists contoured target volumes according to an agreed protocol: gross tumour volume (GTV) and clinical target volume (CTV) on CT/MRI alone, CT/MRI+PET(CT) and CT/MRI+PET(MRI). GTV/CTV Kouwenhoven conformity levels (KCL), regions of contour variation and qualitative differences between PET(CT) and PET(MRI) were evaluated.

RESULTS

There was substantial IOV in contouring. GTV mean KCL: CT/MRI 0.34, CT/MRI+PET(CT) 0.38, CT/MRI+PET(MRI) 0.39 (P = 0.06). CTV mean KCL: CT/MRI 0.31, CT/MRI+PET(CT) 0.35, CT/MRI+PET(MRI) 0.35 (P = 0.04 for all groups; P > 0.05 for individual pairs). One observer consistently contoured largest and one smallest. Observers rarely decreased volumes in relation to PET. Most IOV occurred in bone followed by dural tail, postoperative bed and venous sinuses. Tumour edges were qualitatively clearer on PET(MRI) versus PET(CT), but this did not affect contouring.

CONCLUSION

IOV in contouring challenging meningioma cases was large and only slightly improved with the addition of ⁶⁸Ga DOTATATE PET. Simultaneous PET/MRI for meningioma contouring is feasible, but did not improve IOV versus PET/CT. Whether volumes can be safely reduced according to PET requires evaluation.

Executive function in adolescents with PKU and their siblings: Associations with biochemistry

Previous research shows consistent and marked executive function impairment in children with early and continuously treated phenylketonuria. This between groups analysis (phenylketonuria group vs sibling controls) found no significant differences in executive function (although adolescents with phenylketonuria performed slightly worse than their siblings). Biochemical relationships with executive function were confined to long-term measures of high phenylalanine:tyrosine ratio exposure, as well as tyrosine exposure independent of phenylalanine. This study suggests that early and continuously treated PKU results in non-significant EF differences (compared to siblings), although the influence of long-term exposure to poorer metabolic control is still evident.

A Combination of rhBMP-2 (Recombinant Human Bone Morphogenetic Protein-2) and MEK (MAP Kinase/ERK Kinase) Inhibitor PD0325901 Increases Bone Formation in a Murine Model of Neurofibromatosis Type I Pseudarthrosis

BACKGROUND

Congenital tibial dysplasia is a severe pediatric condition that classically results in a persistent pseudarthrosis. A majority of these cases are associated with neurofibromatosis type I (NF1), a genetic disorder in which inactivation of the NF1 gene leads to overactivity of the Ras-MEK-MAPK (mitogen-activated protein kinase) signaling pathway. We therefore hypothesized that pharmaceutical inhibition of MEK-MAPK may be a beneficial therapeutic strategy.

METHODS

In vitro methods were used to demonstrate a role for the MEK inhibitor PD0325901 in promoting osteogenic differentiation in Nf1^-/- calvarial osteoblasts. Local applications of rhBMP-2 and/or PD0325901 were then tested in a mouse model of NF1 tibial pseudarthrosis featuring localized double inactivation of the Nf1 gene in a fracture. Mice received no treatment, PD0325901 (10 mg/kg/day from two days before fracture to ten days after fracture), rhBMP-2 (10 μg), or a combination of rhBMP-2 and PD0325901.

RESULTS

Animals treated with the delivery vehicle alone, PD0325901, rhBMP-2, or the PD0325901 + rhBMP-2 combination showed union rates of 0%, 8%, 69% (p < 0.01), or 80% (p < 0.01), respectively, at twenty-one days after fracture. Mice treated with the rhBMP-2 + PD0325901 combination displayed a callus volume sixfold greater than the vehicle controls and twofold greater than the group receiving rhBMP-2 alone. Although MEK inhibition combined with rhBMP-2 led to increases in bone formation and union, the proportion of fibrous tissue in the callus was not significantly reduced.

CONCLUSIONS

The data suggest that MEK inhibition can promote bone formation in combination with rhBMP-2 in the context of an NF1 pseudarthrosis. However, PD0325901 did not promote substantive bone anabolism in the absence of an exogenous anabolic stimulus and did not suppress fibrosis.

CLINICAL RELEVANCE

This study examines a signaling pathway-based approach to treating poor bone healing in a model of NF1 pseudarthrosis.