Peptide-scFv antigen recognition domains effectively confer CAR T cell multiantigen specificity

The emergence of immune escape is a significant roadblock to developing effective chimeric antigen receptor (CAR) T cell therapies against hematological malignancies, including acute myeloid leukemia (AML). Here, we demonstrate feasibility of targeting two antigens simultaneously by combining a GRP78-specific peptide antigen recognition domain with a CD123-specific scFv to generate a peptide-scFv bispecific antigen recognition domain (78.123). To achieve this, we test linkers with varying length and flexibility and perform immunophenotypic and functional characterization. We demonstrate that bispecific CAR T cells successfully recognize and kill tumor cells that express GRP78, CD123, or both antigens and have improved antitumor activity compared to their monospecific counterparts when both antigens are expressed. Protein structure prediction suggests that linker length and compactness influence the functionality of the generated bispecific CARs. Thus, we present a bispecific CAR design strategy to prevent immune escape in AML that can be extended to other peptide-scFv combinations.

The feasibility and acceptability of a rewards system based on food purchasing behaviour in secondary school cashless canteens: the Eat4Treats (E4T) cluster feasibility, non-randomised, controlled intervention study

BACKGROUND

Using rewards may be an effective method to positively influence children's eating behaviour but evidence to date is limited, particularly in older children. The cashless canteen systems in schools provides a unique opportunity to implement a food-based reward scheme but intervention development work and feasibility testing is needed. The overall aim of the E4T feasibility study was to examine the feasibility and acceptability of implementing a rewards scheme based on the food purchasing behaviour of pupils in cashless canteens in secondary schools.

METHODS

A non-randomised, controlled, parallel-group cluster feasibility study conducted in four secondary schools (two intervention and two control) serving areas of the highest social deprivation in Northern Ireland. During the 4-month trial, pupils earned points for foods purchased at the school canteen, with better nutritional choices having a higher value. Pupils could exchange the points they earned for rewards (e.g. stationery, vouchers, sports equipment) via the E4T website. Qualitative and quantitative data was collected from year 9 and 10 pupils (boys and girls aged 12-14 years), teachers and canteen staff to address the feasibility questions.

RESULTS

Two intervention (one urban, one rural) and one control (urban) school completed the study. Seventy-one percent of 12-14-year-old pupils consented to take part; 1% of parents opted their child out of the study. Questionnaire completion rates were high (6 and 11% of questionnaires were partially completed at baseline and follow-up respectively). Collecting data on food consumed in the canteen was challenging logistically. Focus groups with pupils indicated that the overall concept of E4T was well received and there was a high degree of satisfaction with the rewards available. Pupils and teachers made several suggestions for improvements.

CONCLUSIONS

E4T was successfully implemented as a result of collaboration between schools, school canteens and cashless canteen providers working with a multidisciplinary research team. It was acceptable to pupils, teachers and canteen staff. The findings suggest a few areas for refining implementation and evaluation processes that would need to be considered in the design of a larger trial, particularly resources required to streamline implementation and ways to optimise pupil engagement.

TRIAL REGISTRATION

Under review with https://www.

CLINICALTRIALS

gov (retrospective registration-reg number and weblink to be added).

Implementation of a pharmacy-driven rapid bacteremia response program

PURPOSE

This report describes a comprehensive pharmacy-driven rapid bacteremia response program.

SUMMARY

This novel program positioned the pharmacy department at a large, community health system to receive and respond to critical microbiologic diagnostic testing results, 24/7/365. The program empowered pharmacists to provide centralized, comprehensive care including assessing blood culture Gram stain results, adjusting antibiotic therapy per protocol, ordering repeat blood cultures, analyzing and interpreting rapid molecular diagnostic test results, placing orders for contact isolation, and communicating antibiotic recommendations to the treatment team. In the first year after program implementation, 2,282 blood culture Gram stains and 2,046 rapid diagnostic test results were called in to the pharmacy department. The program reduced the median time to effective therapy in patients who did not already have active antimicrobial orders from over 10 hours to less than 1 hour. Based on the Gram stain results, antibiotics were started per protocol in 34.2% of patients. Based on the rapid molecular diagnostic test results, adjustments were made to antibiotic regimens in 55.7% of cases after discussion with a provider. Of these adjustments, 39.9% were for escalation of antibiotics and 37.7% were for de-escalation of antibiotics.

CONCLUSION

By expanding the scope of pharmacy practice, barriers to optimizing clinical care were overcome.

Non-targeted LC-MS/MS metabolomic profiling of human plasma uncovers a novel Mediterranean diet biomarker panel

INTRODUCTION

Consumption of a Mediterranean diet (MD) has established health benefits, and the identification of novel biomarkers could enable objective monitoring of dietary pattern adherence.

OBJECTIVES

The present investigation performed untargeted metabolomics on blood plasma from a controlled study of MD adherence, to identify novel blood-based metabolite biomarkers associated with the MD pattern, and to build a logistic regression model that could be used to characterise MD adherence.

METHODS

A hundred and thirty-five plasma samples from n = 58 patients collected at different time points were available. Using a 14-point scale MD Score (MDS) subjects were divided into 'high' or 'low' MDS adherence groups and liquid chromatography-mass spectrometry (LC-MS/MS) was applied for analysis.

RESULTS

The strongest association with MDS was pectenotoxin 2 seco acid (r = 0.53; ROC = 0.78), a non-toxic marine xenobiotic metabolite. Several lipids were useful biomarkers including eicosapentaenoic acid, the structurally related lysophospholipid (20:5(5Z,8Z,11Z,14Z,17Z)/0:0), a phosphatidylcholine (P-18:1(9Z)/16:0) and also xi-8-hydroxyhexadecanedioic acid. Two metabolites negatively correlated with MDS, these were the monoacylglycerides (0:0/16:1(9Z)/0:0) and (0:0/20:3(5Z,8Z,11Z)/0:0). By stepwise elimination we selected a panel of 3 highly discriminatory metabolites and developed a linear regression model which identified 'high MDS' individuals with high sensitivity and specificity [AUC (95% CI) 0.83 (0.76-0.97)].

CONCLUSION

Our study highlights the utility of metabolomics as an approach for developing novel panels of dietary biomarkers. Quantitative profiling of these metabolites is required to validate their utility for evaluating dietary adherence.

Capturing the whole-school food environment in primary schools

OBJECTIVE

The school food environment (SFE) is an ideal setting for encouraging healthy dietary behaviour. We aimed to develop an instrument to assess whole-SFE, test the instrument in the school setting and demonstrate its use to make food environment recommendations.

DESIGN

SFE literature and UK school food guidance were searched to inform instrument items. The instrument consisted of (i) an observation proforma capturing canteen areas systems, food presentation and monitoring of food intake and (ii) a questionnaire assessing food policies, provision and activities. The instrument was tested in schools and used to develop SFE recommendations. Descriptive analyses enabled narrative discussion.

SETTING

Primary schools.

PARTICIPANTS

An observation was undertaken at schools in urban and rural geographical regions of Northern Ireland of varying socio-economic status (n 18). School senior management completed the questionnaire with input from school caterers (n 16).

RESULTS

The instrument captured desired detail and potential instrument modifications were identified. SFE varied. Differences existed between food policies and how policies were implemented and monitored. At many schools, there was scope to enhance physical eating environments (n 12, 67 %) and food presentation (n 15, 83 %); emphasise healthy eating through food activities (n 7, 78 %) and increase parental engagement in school food (n 9, 56 %).

CONCLUSIONS

The developed instrument can measure whole-SFE in primary schools and also enabled identification of recommendations to enhance SFE. Further assessment and adaptation of the instrument are required to enable future use as a research tool or for self-assessment use by schools.

The Norton Healthcare electronic antimicrobial stewardship program: An opt-out approach to antimicrobial stewardship

PURPOSE

To describe the Norton Healthcare electronic antimicrobial stewardship program (E-ASP), a novel prospective audit and feedback approach that leverages the electronic medical record to overcome efficiency barriers. Additionally, to describe an accompanying opt-out antimicrobial stewardship approach that addresses provider nonresponsiveness.

SUMMARY

Prospective audit and feedback is recommended by antimicrobial stewardship guidelines; however, execution can be difficult due to labor requirements, delays in communication, and provider nonparticipation. The Norton E-ASP was developed to address these issues by reliably identifying target patients, documenting assessments, streamlining recommendation delivery, promoting handoff, and providing automated tracking of recommendation responses. Opt-out stewardship allows recommendations to be implemented if not rejected after 24 hours.

CONCLUSION

A 25% reduction in target antimicrobial use has been achieved and sustained with the program. Use of the Norton E-ASP, including opt-out antimicrobial stewardship, broadened the reach and furthered the impact of infectious diseases pharmacists. Successes of this program justified addition of 3 full-time infectious diseases pharmacist positions at a large community health system. This strategy may serve as a model for tele-antimicrobial stewardship or other pharmacy recommendations.

1797. Evaluation of Intravenous vs Oral Antibiotic Therapy at Discharge for the Treatment of Urinary Source Gram-Negative Bacteremia

Background

Retrospective studies demonstrate similar efficacy between oral (PO) and intravenous (IV) antibiotics at discharge for gram negative bacteremia (GNB), with reduced duration of hospitalization, hospital costs, and duration of therapy with PO. Understanding current physician discharge practices can help guide future antimicrobial stewardship initiatives.

Methods

A multicenter, retrospective cohort study was conducted on adult inpatients admitted between July 1, 2020 and June 30, 2021 with urinary source GNB. Patients with both blood and urine cultures positive for Escherichia coli, Klebsiella species, or Proteus mirabilis and a PO antibiotic available at discharge were included. The primary outcome was the percentage of patients discharged on PO antibiotics. Secondary outcomes included duration of hospitalization, total length of therapy, and 30-day readmission secondary to clinical failure or therapeutic complication in the IV and PO at discharge groups.

Results

Of the 157 included patients, 128 (82%) were discharged on PO antibiotics. Patients discharged on IV and PO had similar median quick Pitt bacteremia scores [1(IQR, 0 – 2) vs. 1 (IQR, 0 – 1), p=0.420]. Mean duration of hospitalization for patients discharged on IV vs. PO therapy was 5 (SD, 2.91) days vs. 4 (SD, 2.75) days, p=0.001, respectively. Mean total length of antibiotic therapy was 21.6 (SD, 13.80) days as compared to 13.5 (SD, 4.94) days, p=0.017, for the IV vs. PO arms, respectively. Thirty–day readmission rates were 11/29 (38%) and 23/128 (18%), p=0.035, in the IV and PO arms, respectively. Notably, 21/29 (72%) of the IV arm had an organism from blood culture that was susceptible to trimethoprim-sulfamethoxazole (TMP-SMX).

Conclusion

Most patients with urinary source GNB were discharged on PO antibiotics. Patients discharged on IV antibiotics were more likely to be readmitted within 30 days. Future efforts to decrease IV antibiotic use may focus on increasing TMP-SMX use at discharge.

Disclosures

Matthew Song, PharmD, BCIDP, Merck: Stocks/Bonds|ObsEva: Stocks/Bonds.

Fluoroquinolone stewardship at a community health system: A decade in review

OBJECTIVE

To describe inpatient fluoroquinolone use and susceptibility data over a 10-year period after the implementation of an antimicrobial stewardship program (ASP) led by an infectious diseases pharmacist starting in 2011.

DESIGN

Retrospective surveillance study.

SETTING

Large community health system.

METHODS

Fluoroquinolone use was quantified by days of therapy (DOT) per 1,000 patient days (PD) and reported quarterly. Use data are reported for inpatients from 2016 to 2020. Levofloxacin susceptibility is reported for Pseudomonas aeruginosa and Escherichia coli for inpatients from 2011 to 2020 at a 4 adult-hospital health system.

RESULTS

Inpatient fluoroquinolone use decreased by 74% over a 5-year period, with an average decrease of 3.45 DOT per 1,000 PD per quarter (P < .001). Over a 10-year period, inpatient levofloxacin susceptibility increased by 57% for P. aeruginosa and by 15% for E. coli. P. aeruginosa susceptibility to levofloxacin increased by an average of 2.73% per year (P < .001) and had a strong negative correlation with fluoroquinolone use, r = -0.99 (P = .002). E. coli susceptibility to levofloxacin increased by an average of 1.33% per year (P < .001) and had a strong negative correlation with fluoroquinolone use, r = -0.95 (P = .015).

CONCLUSIONS

A substantial decrease in fluoroquinolone use and increase in P. aeruginosa and E. coli levofloxacin susceptibility was observed after implementation of an antimicrobial stewardship program. These results demonstrate the value of stewardship services and highlight the effectiveness of an infectious diseases pharmacist led antimicrobial stewardship program.

Limited impact of a nudge comment in promoting de-escalation to first-generation cephalosporins in urinary tract infections

In this study, we evaluated the impact of a microbiology nudge on de-escalation to first-generation cephalosporins in hospitalized patients with urinary tract infections secondary to Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis isolates with minimum inhibitory concentrations (MICs) ≤ 16 µg/mL. De-escalation to first generation-cephalosporins was uncommon at MICs = 4-16 µg/mL.

Leukemia’s Next Top Model? Syngeneic Models to Advance Adoptive Cellular Therapy

In recent years, there has been an emphasis on harnessing the immune system for therapeutic interventions. Adoptive cell therapies (ACT) have emerged as an effective option for B-cell derived hematological malignancies. Despite remarkable successes with ACT, immune dysregulation and the leukemia microenvironment can critically alter clinical responses. Therefore, preclinical modeling can contribute to the advancement of ACT for leukemias. Human xenografts, the current mainstay of ACT in vivo models, cannot evaluate the impact of the immunosuppressive leukemia microenvironment on adoptively transferred cells. Syngeneic mouse models utilize murine tumor models and implant them into immunocompetent mice. This provides an alternative model, reducing the need for complicated breeding strategies while maintaining a matched immune system, stromal compartment, and leukemia burden. Syngeneic models that evaluate ACT have analyzed the complexity of cytotoxic T lymphocytes, T cell receptor transgenics, and chimeric antigen receptors. This review examines the immunosuppressive features of the leukemia microenvironment, discusses how preclinical modeling helps predict ACT associated toxicities and dysfunction, and explores publications that have employed syngeneic modeling in ACT studies for the improvement of therapy for leukemias.

Missed Pneumococcal Vaccination Opportunities in Adults With Invasive Pneumococcal Disease in a Community Health System

Background

Adult vaccination programs are suboptimal.

Methods

Pneumococcal vaccination history, and healthcare contact were assessed in patients with invasive pneumococcal disease.

Results

Of the 229 cases, 14% were vaccinated. Observed mortality was 20.1%.

Conclusions

Numerous missed vaccination opportunities were identified.

CAR T cells redirected to cell surface GRP78 display robust anti-acute myeloid leukemia activity and do not target hematopoietic progenitor cells

Developing CAR T cells for acute myeloid leukemia (AML) has been hampered by a paucity of targets that are expressed on AML blasts and not on hematopoietic progenitor cells (HPCs). Here we demonstrate that GRP78 is expressed on the cell surface of primary AML blasts but not HPCs. To target GRP78, we generate T cell expressing a GRP78-specific peptide-based CAR, which show evidence of minimal fratricide post activation/transduction and antigen-dependent T cell differentiation. GRP78-CAR T cells recognize and kill GRP78-positive AML cells without toxicity to HPCs. In vivo, GRP78-CAR T cells have significant anti-AML activity. To prevent antigen-dependent T cell differentiation, we block CAR signaling and GRP78 cell surface expression post activation by using dasatinib during GRP78-CAR T cell manufacturing. This significantly improves their effector function in vitro and in vivo. Thus, targeting cell surface GRP78-positive AML with CAR T cells is feasible, and warrants further active exploration.

105. Fluoroquinolone Stewardship at a Community Health-System: A Decade in Review

Background

Fluoroquinolone stewardship is a common target for antimicrobial stewardship programs seeking to maintain or improve fluoroquinolone susceptibility rates. Additional benefits include reducing C. difficile infection rates, drug toxicities, and resistance to other antimicrobials as fluoroquinolones can co-select for resistance. The Norton Healthcare antimicrobial stewardship program was founded in 2011 and provides services at 4 adult hospitals with ~1600 beds. Main fluoroquinolone stewardship activities have included provider education, prospective audit and feedback, and guideline and order-set development. The purpose of this study was to describe the resistance and usage rates of fluoroquinolones over time.

Methods

This was a descriptive study examining individual adult hospital antibiograms from 2010 to 2020. Levofloxacin susceptibility rates to E. coli and P. aeruginosa were collated from annual antibiograms between 2010 and 2020 for outpatients and each adult hospital. Adult hospital resistance rates were aggregated and weighted accordingly to number of isolates per hospital per year. Additionally, levofloxacin and ciprofloxacin inpatient days of therapy (DOT) was collected since 2016 when DOT was first readily retrievable and was normalized per 1000 patient days to compare between different time points.

Results

Outpatient levofloxacin likelihood of activity against P. aeruginosa improved from 81% to 91%. Outpatient levofloxacin likelihood of activity against E. coli remained stable between 84 – 86% (Figure 1). Adult inpatient fluoroquinolone usage decreased by approximately 75% from 83.5 to 21.37 DOT/1000 patient days since 2016 (Figure 2). Adult inpatient levofloxacin likelihood of activity against P. aeruginosa improved from 53% to 83%. Adult inpatient levofloxacin likelihood of activity against E. coli improved from 65% to 75% (Figure 3).

Conclusion

The Norton Healthcare antimicrobial stewardship program has been effective in reducing unnecessary fluoroquinolone usage and improving inpatient fluoroquinolone susceptibility rates. Future studies should examine opportunities to translate successes to the outpatient phase of care.

Disclosures

Ashley Wilde, PharmD, BCPS-AQ ID, Nothing to disclose Paul S. Schulz, MD, Gilead (Consultant, Speaker’s Bureau)Merck (Consultant, Speaker’s Bureau)

85. Evaluation of Urinalysis and Urine Culture Use at a Community Health-system

Background

The Infectious Diseases Society of America asymptomatic bacteriuria (ASB) guidelines recommend against screening for or treating ASB in most patients without symptoms of a urinary tract infection (UTI). The purpose of this study was to characterize current urine testing practices and their potential impact on identification and treatment of asymptomatic bacteriuria on hospitalized adults.

Methods

This retrospective, point prevalence study conducted at a 4 hospital community health-system that included all inpatients ≥ 18 years old present on November 13^th, 2019. Patients were excluded if they were admitted or transferred to either a labor & delivery or mother-baby unit. A chart review was performed for a sub-group of patients with abnormal urine testing, with a target sample size of 200 (n=50 from each hospital). The primary outcome was the prevalence of patients with a urinalysis, urine culture, or both performed during their admission. Secondary outcomes included abnormal urine testing in the overall cohort and symptomatology and antibiotic use in the sub-group (Figure 1).

Results

947 patients met inclusion criteria. Of those patients, 516 (54%) had urine testing performed during their admission. 322 (34%) patients had abnormal urine testing results (Table 1). In the sub-group, 192 patients with abnormal urine tests were included. Antibiotics with a documented indication of UTI were administered to 66 (34%) patients. Of those given antibiotics with a UTI indication, 49/66 (74%) did not have documented signs or symptoms of a UTI (Figure 2).

Conclusion

Urine testing was performed on the majority of admitted adult patients. Unnecessary testing likely contributes to guideline discordant screening and treatment of ASB. Future studies are needed to identify effective diagnostic stewardship interventions to decrease screening and treatment of ASB.

Disclosures

Ashley Wilde, PharmD, BCPS-AQ ID, Nothing to disclose

Interannual variability in acoustic detection of blue and fin whale calls in the Northeast Atlantic High Arctic between 2008 and 2018

Northern Hemisphere blue and fin whales are regular summer migrants to Arctic waters. Given the profound changes the Arctic is currently undergoing due to global warming, changes in habitat use and distribution of these migratory species are predicted. In this study, 3 passive acoustic recorders, 2 in Fram Strait about 95 km apart and 1 north of the Svalbard Archipelago (Atwain), were used to investigate the spatial and temporal vocal occurrence of these species in the Northeast Atlantic High Arctic. Acoustic data were available for 7 years for western Fram Strait (WFS), 2.5 years for central Fram Strait (CFS) and 3 years for Atwain. At both Fram Strait locations, most blue whale call detections occurred from August through October, though recently (2015-2018) in WFS a clear increase in blue whale call rates was detected in June/July, suggesting an expansion of the seasonal occurrence of blue whales. In WFS, fin whale calls were detected intermittently, at low levels, almost year-round. In CFS, fin whale calls were more frequent but occurred mainly from July through December. At Atwain, blue whale detections commenced in July, both species were recorded in September/October and fin whale calls extended into November. Results from this study provide novel long-term baseline information about the occurrence of blue and fin whales at extreme northerly locations, where traditional ship-based survey methods are seasonally limited. Continued sampling will support investigation of how environmental change influences cetacean distribution and habitat use.

Food environment intervention improves food knowledge, wellbeing and dietary habits in primary school children: Project Daire, a randomised-controlled, factorial design cluster trial

Background

Evidence suggests that dietary intake of UK children is suboptimal. As schools provide an ideal natural environment for public health interventions, effective and sustainable methods of improving food knowledge and dietary habits in this population must be identified. Project Daire aimed to improve children’s health-related quality of life, wellbeing, food knowledge and dietary habits via two multi-component interventions.

Methods

Daire was a randomised-controlled, factorial design trial evaluating two interventions across four arms. Primary schools in Northern Ireland were randomised to one of four 6-month intervention arms: i) ‘Nourish’, ii) ‘Engage’, iii) ‘Nourish’ and ‘Engage’ and iv) Control (Delayed). ‘Nourish’ was an intervention aiming to alter the whole-school food environment, provide food-related experiences and exposure to locally produced foods. ‘Engage’ was an age-appropriate, cross-curricular educational intervention on food, agriculture, nutrition science and related careers. Primary outcomes were emotional and behavioural wellbeing and health-related quality of life. A number of secondary outcomes, including dietary intake, cooking competence and food-related knowledge, were also measured.

Results

Fifteen schools from areas of varying socio-economic status participated in the randomised trial. A total of 903 (n = 445 aged 6–7 years and n = 458 aged 10–11 years) primary school pupils took part. Total Difficulties Score improved in all pupils (6–7 and 10–11 year old pupils) who received the ‘Nourish’ intervention compared with those that did not (adjusted difference in mean = − 0.82; 95% CI -1.46, − 0.17; P < 0.02). No statistically significant difference in Health-Related Quality of Life was observed. The ‘Nourish’ intervention also produced some changes in school-based dietary behaviour, which were most apparent in the 10–11 year old pupils. The ‘Nourish’ intervention also produced improvements in understanding of food labels (adjusted difference in mean = 0.15; 95% CI 0.05, 0.25; P < 0.01) and knowledge of vegetables in season (adjusted difference in mean = 0.29; 95% CI 0.01,0.56; P = 0.04) whilst an increased willingness to try new foods and improved perceived cooking competence was also observed.

Conclusions

Improvements in childhood emotional and behavioural wellbeing, dietary intake, knowledge about food, cooking skills and willingness to try new foods were associated with the ‘Nourish’ whole-school food environment intervention. Exploration of the sustainability and long-term effectiveness of such whole-school food interventions should be conducted.

Trial registration

National Institute of Health (NIH) U.S. National Library of Medicine Clinical Trials.gov (ID: NCT04277312).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-021-01086-y.

CooC11 and CooC7: the development and validation of age appropriate children's perceived cooking competence measures

BACKGROUND

Learning cooking skills during childhood and adolescence is associated with positive dietary outcomes in adulthood as well as being tracked from adolescence to adulthood. In addition studies have found that perceived competence to be a greater motivator to perform a behaviour than actual competence. However, a lack of validated tools that effectively measure behavioural and dietary changes including cooking confidence in children is a limitation. Therefore, this research aimed to develop and validate age-appropriate perceived cooking competence measures for younger and older primary school aged children.

METHODS

Two measures of perceived Cooking Competence (CooC11 and CooC7) for older (8-12 years) and younger (6-7 years) children were developed from a critical evaluation of publically available recommendations and expert consultation. The cooking skills within the measures were illustrated by a graphic designer in consultation with a chef and reviewed in an iterative manner by the research team. The measures were piloted for clarity, ease of use and initial face validity. Multiple studies were used for both CooC11 and CooC7 to establish psychometric properties of the measures, temporal stability, internal consistency reliability, construct validity, as well as responsiveness to change for CooC11. Analysis included Exploratory Factor Analysis, Confirmatory Factor Analysis, Intraclass Correlation Coefficients, Pearson's Correlations, ANOVAs and Cronbach's Alphas.

RESULTS

Both measures had high levels of face validity and received positive user feedback. Two factors were shown in both measures with the measures showing excellent temporal stability (ICC > 0.9) and good internal consistency (Cronbach's Alphas > 0.7). Both measures showed initial discriminant validity, with significant differences (P< 0.001) between those who reported assisting their parents with dinner preparation and those who did not. Additionally, CooC11 was significantly correlated with an adult cooking measure and had a significant responsiveness to change (P< 0.01).

CONCLUSIONS

The CooC11 and CooC7 are the first validated age-appropriate measures for assessing children's perceived Cooking Competence for ages 8-12 and 6-7 years respectively. They can be used to evaluate the efficacy of children's cooking intervention studies or school nutrition education programmes.

A mixed methods pilot randomised controlled trial to develop and evaluate the feasibility of a Mediterranean diet and lifestyle education intervention 'THINK-MED' among people with cognitive impairment

BACKGROUND

Accumulating evidence supports the role of a Mediterranean diet (MD) in cognition, with a greater adherence to a MD associated with reduced dementia risk. It is important to understand how best to achieve behaviour change towards a MD, particularly in non-Mediterranean and high-risk populations. The aim of this study was to evaluate the feasibility of a MD and lifestyle education intervention (THINK-MED) among older adults with cognitive impairment.

METHODS

Qualitative interviews (Phase I), conducted with mild cognitive impairment (MCI) participants, evaluated the intervention materials to allow refinement before pilot testing. THINK-MED was a 12-month, pilot RCT (Phase II) whereby MCI participants were randomised into one of three groups: education on one occasion vs education staged and supported by a dietitian vs control. The primary outcome was a change in MD score. Secondary outcome measurements were collected to gather data on variability of the outcomes to inform a full trial power calculation and to test their acceptability. Slower recruitment rates necessitated a change in primary outcome to a revised focus primarily on feasibility. A sub-study of the same THINK-MED intervention and data collection measures was also conducted among community-dwelling participants with subjective cognitive impairment (SCI) (NCT03569319).

RESULTS

A total of 20 participants (n = 15 MCI; n = 5 SCI) were enrolled in the THINK-MED study. However, there were 10 (50%) participants (n = 9 MCI; n = 1 SCI) who withdrew from the study. Although, those who remained in the intervention rated and evaluated their experience as generally positive, recruitment and retention, especially from a MCI population, was extremely challenging. This highlights the complex needs of this heterogeneous clinical cohort. Recruiting participants from a community-based sample with SCI was more feasible, reaching a wider audience in a shorter time period. There were challenges relating to data collection and incompleteness, with the occurrence of missing data particularly among the questionnaire-based assessments.

CONCLUSIONS

Owing to the challenges with recruitment and retention of older adults with cognitive impairment in this study, it is difficult to confirm if this intervention is feasible. This research has highlighted considerations for a future trial, including a review of the recruitment strategies used and prioritisation of the outcome measures assessed.

TRIAL REGISTRATION

Clinical trials registration NCT03265522 / NCT03569319.

Sustained virologic suppression with abacavir, emtricitabine, and crushed dolutegravir and tenofovir alafenamide in a patient with HIV and eosinophilic esophagitis

We report the use of crushed dolutegravir (DTG) and tenofovir alafenamide (TAF) tablets in a 27-year-old man with progressive dysphagia due to eosinophilic esophagitis, which severely limited compliance, leading to viral resistance. Based on his drug resistance history, allergies, and inability to swallow tablets intact, he was transitioned to DTG 50 mg (crushed), TAF 25 mg (crushed), liquid abacavir (20 mg/ml) 30 ml, and liquid emtricitabine (10 mg/ml) 24 ml orally daily. After receiving this regimen for five months, the patient’s HIV viral load decreased from 9910 to 59 copies/ml and after ten total months became suppressed at <20 copies/ml. Our case report suggests administration of crushed DTG and TAF tablets may be a viable option for patients with dysphagia and limited treatment options.

1547. Modeling Pharmacokinetics and Pharmacodynamics of Meropenem Utilizing a Novel Infusion Method of Bolus to Prolonged Infusion

Background

Dose optimization of antibiotics has been shown to increase the likelihood of achieving pharmacodynamic efficacy targets and improve clinical outcomes. For carbapenems, achieving greater than 40% time above minimum inhibitory concentration (T>MIC) has been shown to be correlated with clinical efficacy. Increasing bacterial resistance and rising MICs makes it more difficult for clinicians to rely on traditional dosing strategies to meet pharmacodynamic goals. Further optimization methods beyond extended infusion may be necessary to achieve certain pharmacodynamics goals.

Methods

We performed a Monte Carlo simulation investigating a novel method of meropenem administration, bolus to prolonged infusion (BPI). Multiple meropenem dosing regimens utilizing BPI were evaluated over 5000 patients utilizing pharmacokinetic profiles from 30 total patients. Patients were studied in 3 separate groups: <120 kg, ≥120 kg/non-critically ill and ≥120 kg/critically-ill. Bolus doses varied from 250–1000 mg and were paired with infusion doses varying from 500–1500 mg. Bolus plus infusion time totaled 3 hours and each dose was modeled with an 8-hour interval for both first dose and at steady state; BPI dosing was utilized for each dose. The primary outcome was probability of target attainment (PTA) of 40% time above minimum inhibitory concentration (T>MIC). Secondary outcomes included PTA 54% T>MIC and PTA 100% T>MIC.

Results

All doses studied achieved > 90% PTA of 40% T>MIC for MICs of ≤8 μg/mL at both first dose and steady state in the <120 kg and ≥120 kg/non-critically ill patient groups. In the ≥120 kg/critically ill patient group, all doses achieved > 90% PTA of 40% T>MIC for MICs of ≤4 μg/mL.

Conclusion

BPI achieves high probability of target attainment at nonresistant MICs for Pseudomonas aeruginosa and enteric Gram-negative organisms across the 3 patient groups studied.

Disclosures

All authors: No reported disclosures.

Application of 1H-NMR Metabolomics for the Discovery of Blood Plasma Biomarkers of a Mediterranean Diet

The Mediterranean diet (MD) is a dietary pattern well-known for its benefits in disease prevention. Monitoring adherence to the MD could be improved by discovery of novel dietary biomarkers. The MEDiterranean Diet in Northern Ireland (MEDDINI) intervention study monitored the adherence of participants to the MD for up to 12 months. This investigation aimed to profile plasma metabolites, correlating each against the MD score of participants (n = 58). Based on an established 14-point scale MD score, subjects were classified into two groups (“low” and “high”). ¹H-Nuclear Magnetic Resonance (¹H-NMR) metabolomic analysis found that citric acid was the most significant metabolite (p = 5.99 × 10⁻⁴*; q = 0.03), differing between ‘low’ and ‘high’. Furthermore, five additional metabolites significantly differed (p < 0.05; q < 0.35) between the two groups. Discriminatory metabolites included: citric acid, pyruvic acid, betaine, mannose, acetic acid and myo-inositol. Additionally, the top five most influential metabolites in multivariate models were also citric acid, pyruvic acid, betaine, mannose and myo-inositol. Metabolites significantly correlated with the consumption of certain food types. For example, citric acid positively correlated fruit, fruit juice and vegetable constituents of the diet, and negatively correlated with sweet foods alone or when combined with carbonated drinks. Citric acid was the best performing biomarker and this was enhanced by paired ratio with pyruvic acid. The present study demonstrates the utility of metabolomic profiling for effectively assessing adherence to MD and the discovery of novel dietary biomarkers.

Development of a peer support intervention to encourage dietary behaviour change towards a Mediterranean diet in adults at high cardiovascular risk

BACKGROUND

Mediterranean diet (MD) interventions are demonstrated to significantly reduce cardiovascular disease (CVD) risk but are typically resource intensive and delivered by health professionals. There is considerable interest to develop interventions that target sustained dietary behaviour change and that are feasible to scale-up for wider public health benefit. The aim of this paper is to describe the process used to develop a peer support intervention to encourage dietary behaviour change towards a MD in non-Mediterranean adults at high CVD risk.

METHODS

The Medical Research Council (MRC) and Behaviour Change Wheel (BCW) frameworks and the COM-B (Capability, Opportunity, Motivation, Behaviour) theoretical model were used to guide the intervention development process. We used a combination of evidence synthesis and qualitative research with the target population, health professionals, and community health personnel to develop the intervention over three main stages: (1) we identified the evidence base and selected dietary behaviours that needed to change, (2) we developed a theoretical basis for how the intervention might encourage behaviour change towards a MD and selected intervention functions that could drive the desired MD behaviour change, and (3) we defined the intervention content and modelled outcomes.

RESULTS

A theory-based, culturally tailored, peer support intervention was developed to specifically target behaviour change towards a MD in the target population. The intervention was a group-based program delivered by trained peer volunteers over 12-months, and incorporated strategies to enhance social support, self-efficacy, problem-solving, knowledge, and attitudes to address identified barriers to adopting a MD from the COM-B analysis.

CONCLUSIONS

The MRC and BCW frameworks provided a systematic and complementary process for development of a theory-based peer support intervention to encourage dietary behaviour change towards a MD in non-Mediterranean adults at high CVD risk. The next step is to evaluate feasibility, acceptability, and diet behaviour change outcomes in response to the peer support intervention (change towards a MD and nutrient biomarkers) using a randomized controlled trial design.

Trial to Encourage Adoption and Maintenance of a Mediterranean Diet (TEAM-MED): Protocol for a Randomised Feasibility Trial of a Peer Support Intervention for Dietary Behaviour Change in Adults at High Cardiovascular Disease Risk

Adoption of a Mediterranean diet (MD) reduces cardiovascular disease (CVD) risk. However, interventions to achieve dietary behaviour change are typically resource intensive. Peer support offers a potentially low-cost approach to encourage dietary change. The primary objective of this randomised controlled trial is to explore the feasibility of peer support versus a previously tested dietetic-led intervention to encourage MD behaviour change, and to test recruitment strategies, retention and attrition in order to inform the design of a definitive trial. A total of 75 overweight adults at high CVD risk who do not follow a MD (Mediterranean Diet Score (MDS ≤ 3)) will be randomly assigned to either: a minimal intervention (written materials), a proven intervention (dietetic support, written materials and key MD foods), or a peer support intervention (group-based community programme delivered by lay peers) for 12 months. The primary end-point is change in MDS from baseline to 6 months (adoption of MD). Secondary end-points include: change in MDS from 6 to 12 months (maintenance of MD), effects on nutritional biomarkers and CVD risk factors, fidelity of implementation, acceptability and feasibility of the peer support intervention. This study will generate important data regarding the feasibility of peer support for ease of adoption of MD in an 'at risk' Northern European population. Data will be used to direct a larger scale trial, where the clinical efficacy and cost-effectiveness of peer support will be tested.

A qualitative analysis exploring preferred methods of peer support to encourage adherence to a Mediterranean diet in a Northern European population at high risk of cardiovascular disease

BACKGROUND

Epidemiological and randomised controlled trial evidence demonstrates that adherence to a Mediterranean diet (MD) can reduce cardiovascular disease (CVD) risk. However, methods used to support dietary change have been intensive and expensive. Peer support has been suggested as a possible cost-effective method to encourage adherence to a MD in at risk populations, although development of such a programme has not been explored. The purpose of this study was to use mixed-methods to determine the preferred peer support approach to encourage adherence to a MD.

METHODS

Qualitative (focus groups) and quantitative methods (questionnaire and preference scoring sheet) were used to determine preferred methods of peer support. Sixty-seven high CVD risk participants took part in 12 focus groups (60% female, mean age 64 years) and completed a questionnaire and preference scoring sheet. Focus group data were transcribed and thematically analysed.

RESULTS

The mean preference score (1 being most preferred and 5 being least preferred) for group support was 1.5, compared to 3.4 for peer mentorship, 4.0 for telephone peer support and 4.0 for internet peer support. Three key themes were identified from the transcripts: 1. Components of an effective peer support group: discussions around group peer support were predominantly positive. It was suggested that an effective group develops from people who consider themselves similar to each other meeting face-to-face, leading to the development of a group identity that embraces trust and honesty. 2. Catalysing Motivation: participants discussed that a group peer support model could facilitate interpersonal motivations including encouragement, competitiveness and accountability. 3. Stepping Stones of Change: participants conceptualised change as a process, and discussed that, throughout the process, different models of peer support might be more or less useful.

CONCLUSION

A group-based approach was the preferred method of peer support to encourage a population at high risk of CVD to adhere to a MD. This finding should be recognised in the development of interventions to encourage adoption of a MD in a Northern European population.

Barriers to adopting a Mediterranean diet in Northern European adults at high risk of developing cardiovascular disease

BACKGROUND

Strong evidence links the consumption of a Mediterranean diet (MD) with a reduced cardiovascular disease (CVD) risk; however, there is uncertainty as to whether non-Mediterranean regions will adopt this diet. The present qualitative research aimed to investigate attitudes towards a MD in individuals at high CVD risk in a Northern European population. This information is needed to inform development of MD interventions in non-Mediterranean high-risk populations.

METHODS

Focus groups (n = 12) were held with individuals at high CVD risk from Northern Europe (≥2 CVD risk factors, aged ≥50 years, no established CVD/type 2 diabetes). Attitudes to dietary change towards a MD were explored. Data were analysed using inductive thematic analysis.

RESULTS

Sixty-seven adults participated (60% female, mean age 64 years). There was some awareness of the term MD but limited knowledge of its composition. Barriers to general dietary change were evident, including perception of expense, concern over availability, expectation of time commitment, limited knowledge, lack of cooking skills, amount and conflicting nature of media information on diets, changing established eating habits and resistance to dietary change. Barriers specific to MD adoption were also identified, including perceived difficulty living in a colder climate, perceived impact on body weight, acceptability of a MD and cultural differences.

CONCLUSIONS

Knowledge of a MD was limited in this Northern European sample at high CVD risk. In addition to general barriers to dietary change, barriers specific to a MD were identified. These findings have implications for the development of interventions aiming to promote MD adoption in non-Mediterranean populations.

Clinical importance of bilateral disease in patients with papillary thyroid cancer

ABSTRACT

A cancer-related factor that is not included in papillary thyroid cancer (PTC) prognostic scoring systems is bilaterality. While it may seem that bilaterality should be considered during the management of PTC, its clinical importance has been debated. This controversy exists because the extent of surgery for PTC has not been found to affect survival in low-risk individuals, despite their potential for PTC bilaterality. We sought to determine if PTC bilaterality is a cancer prognosticator based upon its association with known clinical and pathological PTC prognosticators, and MACIS scores. In this article we discuss our findings and their potential clinical implications.

Cortical specialisation to social stimuli from the first days to the second year of life: A rural Gambian cohort

Brain and nervous system development in human infants during the first 1000 days (conception to two years of age) is critical, and compromised development during this time (such as from under nutrition or poverty) can have life-long effects on physical growth and cognitive function. Cortical mapping of cognitive function during infancy is poorly understood in resource-poor settings due to the lack of transportable and low-cost neuroimaging methods. Having established a signature cortical response to social versus non-social visual and auditory stimuli in infants from 4 to 6 months of age in the UK, here we apply this functional Near Infrared Spectroscopy (fNIRS) paradigm to investigate social responses in infants from the first postnatal days to the second year of life in two contrasting environments: rural Gambian and urban UK. Results reveal robust, localized, socially selective brain responses from 9 to 24 months of life to both the visual and auditory stimuli. In contrast at 0–2 months of age infants exhibit non-social auditory selectivity, an effect that persists until 4–8 months when we observe a transition to greater social stimulus selectivity. These findings reveal a robust developmental curve of cortical specialisation over the first two years of life.

Using fNIRS to Study Working Memory of Infants in Rural Africa

A pilot study was conducted to assess the feasibility of using fNIRS as an alternative to behavioral assessments of cognitive development with infants in rural Africa. We report preliminary results of a study looking at working memory in 12-16-month-olds and discuss the benefits and shortcomings for the potential future use of fNIRS to investigate the effects of nutritional insults and interventions in global health studies.

Arsenic remediation by formation of arsenic sulfide minerals in a continuous anaerobic bioreactor

Arsenic (As) is a highly toxic metalloid that has been identified at high concentrations in groundwater in certain locations around the world. Concurrent microbial reduction of arsenate (As(V) ) and sulfate (SO4 (2-) ) can result in the formation of poorly soluble arsenic sulfide minerals (ASM). The objective of this research was to study As biomineralization in a minimal iron environment for the bioremediation of As-contaminated groundwater using simultaneous As(V) and SO4 (2-) reduction. A continuous-flow anaerobic bioreactor was maintained at slightly acidic pH (6.25-6.50) and fed with As(V) and SO4 (2-) , utilizing ethanol as an electron donor for over 250 d. A second bioreactor running under the same conditions but lacking SO4 (2-) was operated as a control to study the fate of As (without S). The reactor fed with SO4 (2-) removed an average 91.2% of the total soluble As at volumetric rates up to 2.9 mg As/(L · h), while less than 5% removal was observed in the control bioreactor. Soluble S removal occurred with an S to As molar ratio of 1.2, suggesting the formation of a mixture of orpiment- (As2 S3 ) and realgar-like (AsS) solid phases. Solid phase characterization using K-edge X-ray absorption spectroscopy confirmed the formation of a mixture of As2 S3 and AsS. These results indicate that a bioremediation process relying on the addition of a simple, low-cost electron donor offers potential to promote the removal of As from groundwater with naturally occurring or added SO4 (2-) by precipitation of ASM.

The effects of maternal iron deficiency on infant fibroblast growth factor-23 and mineral metabolism

Fibroblast growth factor-23 (FGF23), a phosphate(Phos)-regulating hormone, is abnormally elevated in hypophosphataemic syndromes and an elevated FGF23 is a predictor of mortality in kidney disease. Recent findings suggest iron deficiency as a potential mediator of FGF23 expression and murine studies have shown in utero effects of maternal iron deficiency on offspring FGF23 and phosphate metabolism. Our aim was to investigate the impact of maternal iron status on infant FGF23 and mineral metabolites over the first 2years of life. Infants born to mothers with normal (NIn=25,) and low (LIn=25) iron status during pregnancy, from a mother-infant trial (ISRCTN49285450) in rural Gambia, West Africa, had blood and plasma samples analysed at 12, 24, 52, 78 and 104weeks (wk) of age. Circulating intact-FGF23 (I-FGF23), Phos, total alkaline phosphatase (TALP) and haemoglobin (Hb) decreased and estimated glomerular filtration rate increased over time [all P≤0.0001)]. C-terminal-FGF23 (C-FGF23) and TALP were significantly higher in LI compared with NI, from 52wk for C-FGF23 [Beta coefficient (SE) 18.1 (0.04) %, P=0.04] and from 24wk for TALP [44.7 (29.6) U/L, P=0.04]. Infant Hb was the strongest negative predictor of C-FGF23 concentration [-21% (4%) RU/mL, P≤0.0001], Phos was the strongest positive predictor of I-FGF23 [32.0(3.9) pg/mL, P≤0.0001] and I-FGF23 did not predict C-FGF23 over time [-0.5% (0.5%), P=0.3]. In conclusion, this study suggests that poor maternal iron status is associated with a higher infant C-FGF23 and TALP but similar I-FGF23 concentrations in infants and young children. These findings further highlight the likely public health importance of preventing iron deficiency during pregnancy. Whether or not children who are born to iron deficient mothers have persistently high concentrations of these metabolites and are more likely to be at risk of impaired bone development and pre-disposed to rickets requires further research.

Adaptation of a methanogenic consortium to arsenite inhibition

Arsenic (As) is a ubiquitous metalloid known for its adverse effects to human health. Microorganisms are also impacted by As toxicity, including methanogenic archaea, which can affect the performance of process in which biological activity is required (i.e. stabilization of activated sludge in wastewater treatment plants). The novel ability of a mixed methanogenic granular sludge consortium to adapt to the inhibitory effect of arsenic (As) was investigated by exposing the culture to approximately 0.92 mM of AsIII for 160 d in an arsenate (AsV) reducing bioreactor using ethanol as the electron donor. The results of shaken batch bioassays indicated that the original, unexposed sludge was severely inhibited by arsenite (AsIII) as evidenced by the low 50% inhibition concentrations (IC50) determined, i.e., 19 and 90 μM for acetoclastic- and hydrogenotrophic methanogenesis, respectively. The tolerance of the acetoclastic and hydrogenotrophic methanogens in the sludge to AsIII increased 47-fold (IC50 = 910 μM) and 12-fold (IC50= 1100 μM), respectively, upon long-term exposure to As. In conclusion, the methanogenic community in the granular sludge demonstrated a considerable ability to adapt to the severe inhibitory effects of As after a prolonged exposure period.

Influence of selected factors on the dietary compositions of three targeted and co-occurring temperate species of reef fishes: implications for food partitioning

The dietary compositions of three medium to large targeted fish species, which co-occur over reefs in temperate waters of south-western Australia, were determined. These data were then used to ascertain statistically the extent to which body size, season and habitat influence the diets of these species and the degree to which food resources were partitioned among and within those species, and thus reduced the potential of interspecific and intraspecific competition. On the west coast, Bodianus frenchii (Labridae) and Epinephelides armatus (Serranidae) spent their whole life over prominent limestone reefs, as did Glaucosoma hebraicum (Glaucosomatidae) in all but juvenile life, when it lived over low-relief, limestone substrata. The dietary composition of each species changed with increasing body size, which, in G. hebraicum, was particularly pronounced at c. 300 mm total length (L(T)) and therefore at the size when this species shifts habitat. When the three species co-occurred over the same reefs, their dietary compositions were significantly different, with that of B. frenchii being by far the most discrete, reflecting a far greater contribution by sedentary taxa. Thus, the diet of B. frenchii was distinguished from those of the other two species in containing substantial volumes of bivalve and gastropod molluscs and echinoid echinoderms and essentially no teleosts. Although the diets of G. hebraicum and particularly E. armatus were dominated by teleosts, and especially for larger individuals, the former species ingested greater volumes of cephalopods and small crustaceans. The pointed jaws of B. frenchii, with their forwardly directed and interlocking anterior incisors, are ideally adapted for biting and retaining their invertebrate prey, which are attached to or reside within reef crevices. In contrast, the mouths of G. hebraicum and E. armatus are broader and rounder and contain numerous small, slender and inward-pointing teeth. These teeth, in conjunction with prominent backward-curved canines in E. armatus, facilitate the capture and retention of fish prey. Observations in situ indicate that G. hebraicum is a suction feeder, while E. armatus is predominantly a ram feeder. Although reef environments on the west and south coasts differ, the diet of B. frenchii on these coasts differed only slightly. Interspecific differences in diet, combined with size-related changes in dietary compositions and the occupation of different habitats by juvenile and adult G. hebraicum, reduce the potential for competition for food resources among and within B. frenchii, G. hebraicum and E. armatus and thus helps facilitate the coexistence of these species which historically have been abundant over reefs in south-western Australia.

Use of bioelectrical impedance analysis to assess body composition in rural Gambian children

OBJECTIVE

To validate the Tanita BC-418MA Segmental Body Composition Analyser and four-site skinfold measurements for the prediction of total body water (TBW), percentage fat-free mass (%FFM) and percentage body fat (%BF) in a population of rural Gambian children.

SUBJECTS/METHODS

One hundred and thirty-three healthy Gambian children (65 males and 68 females). FFM estimated by the inbuilt equations supplied with the Tanita system was assessed by comparison with deuterium oxide dilution and novel prediction equations were produced. Deuterium oxide dilution was also used to develop equations for %BF based on four-site skinfolds (biceps, triceps, subscapular and suprailiac).

RESULTS

The inbuilt equations underestimated FFM compared to deuterium oxide dilution in all the sex and age categories (P<0.003), with greater accuracy in younger children and in males. The best prediction of %FFM was obtained from the variables height, weight, sex, impedance, age and four skinfold thickness measurements (adjusted R(2)=0.84, root mean square error (MSE)=2.07%).

CONCLUSIONS

These data suggest that the Tanita instrument may be a reliable field assessment technique in African children, when using population and gender-specific equations to convert impedance measurements into estimates of FFM.

Ethnic differences in the association between body mass index and impedance index (Ht2/Z) in adult women and men using a leg-to-leg bioimpedance method

BACKGROUND

Ethnic differences in the association between body mass index (BMI) and body fat suggest that body composition varies across ethnic groups.

OBJECTIVE

To investigate the association between impedance index - a measure of tissue resistivity - and BMI in adults of different ethnic groups (Asian Indians, West Africans and White Caucasians) living in their native countries.

METHODS

Male (n=329) and female (n=277) adult subjects (18-50 years) living in urban areas in the UK, The Gambia and Pakistan were studied. Body weight and height were measured and BMI calculated. The same leg-to-leg bioimpedance instrument was used in each study and impedance index (height(2) (cm)/impedance (Omega)) used as measure of tissue resistivity.

RESULTS

In women, Asian Indians and West Africans had a significantly greater increase in impedance index per unit increase in BMI compared with white Caucasians (P<0.001). In men, Asian Indians had a significantly lower impedance index compared with West Africans and white Caucasians (P<0.001).

CONCLUSION

Different ethnic groups may have different tissue resistivity for the same BMI indicative of systematic differences in body composition.

Conductometric and fluorometric investigations on the mixed micellar systems of cationic surfactants in aqueous media

Micellar properties of binary mixtures of hexadecyldiethylethanolammonium bromide surfactant with tetradecyldimethylammonium, trimethylammonium, triphenylphosphonium, diethylethanolammonium, and pyridinium bromide surfactants have been characterized employing conductometric and fluorescence techniques. The critical micelle concentration (cmc*) and the degree of counter-ion binding values (delta) of the binary systems were determined from the conductivity measurements. The results were analyzed in light of various existing theories to calculate micellar composition, activity coefficients, and the interaction parameter (beta). Partial contribution of each surfactant, cmc1*, cmc2*, to the overall cmc* value was also evaluated. Aggregation numbers and micropolarity of the mixed micelles were determined from fluorescence measurements. The results were discussed in terms of synergetic interactions in these systems on the basis of the head group/head group and tail/tail interactions and the counter-ion binding.

Fluorescence quenching of Safranine T by inorganic anions in Tween micelles

The fluorescence quenching of the dye Safranine T by various inorganic anions such as [Fe(CN6)]–3, [Fe(CN6)]–4, I–, Br–, NO2–, and N3– in aqueous solution and in nonionic micellar solutions of Tweens (Tween 20, Tween 40, and Tween 80) was studied. The Stern–Volmer quenching constants and quenching rate constants were evaluated. Compared to the quenching efficiency in aqueous media, that of the micellar media was found to be lower, except when iodide ion was used as a quencher. With the exception of the iodide ion, it has been established that collisional quenching plays a major role in the photophysical process. In the case of the iodide ion, both static and collisional quenching processes play a major role, owing to the complexation of iodide ion with Tween micelles. The Stern–Volmer quenching constants were found to be dependent on the ionic strength of the medium.Key words: fluorescence, static quenching, Tweens, Stern–Volmer constant, micellar media.

Early programming of adult diseases in resource poor countries

Considerable evidence now exists to suggest that early exposure to nutritional deprivation can have long term consequences to health, with low birth weight now considered a risk factor for later health outcomes such as coronary heart disease, stroke, type 2 diabetes, and the metabolic syndrome. Of importance, such effects are most exaggerated when faced with over-nutrition in later life, forming the basis for the "thrifty phenotype" hypothesis. The evidence in support of these associations comes largely from retrospective cohort studies in which adult outcomes were correlated with birth weight records. Relatively little data is available from developing countries, where long term record keeping of birth weight data has not been a high priority. Arguably however, such countries are at the greatest risk from the mismatch of early nutritional deprivation and later nutritional affluence. This paper explores the importance of the "developmental origins of health and disease" hypothesis in resource poor countries.

Nogo A expression in the adult enteric nervous system

Neuronal plasticity plays an important role in physiological and pathological processes within the gastrointestinal (GI) tract. Nogo A is a major contributor to the negative effect central nervous system (CNS) myelin has on neurite outgrowth after injury and may also play a role in maintaining synaptic connections in the healthy CNS. Nogo A is highly expressed during neuronal development but in the CNS declines postnatally concomitantly with a loss of regenerative potential while ganglia of the Peripheral Nervous System (PNS) retain Nogo A. The enteric nervous system shares a number of features in common with the CNS, thus the peripheral distribution of factors affecting plasticity is of interest. We have investigated the distribution of Nogo in the adult mammalian gastrointestinal tract. Nogo A mRNA and protein are detectable in the adult rat GI tract. Nogo A is expressed heterogeneously in enteric neurons throughout the GI tract though expression levels appear not to be correlated with neuronal sub-type. The pattern of expression is maintained in cultured myenteric plexus from the guinea-pig small intestine. As is seen in developing neurons of the CNS, enteric Nogo A is present in both neuronal cell bodies and axons. Our results point to a hitherto unsuspected role for Nogo A in enteric neuronal physiology.

Ethnic differences in the relationship between fasting leptin and BMI in children

OBJECTIVE

To compare the relationship between fasting serum leptin levels and body mass index (BMI) in children from different ethnic groups.

SUBJECTS

Children aged 6-10 y from rural Gambia (n=471) and central Italy (n=839).

MEASUREMENTS

Anthropometry (z-score of BMI) and fasting serum leptin concentrations.

RESULTS

The Italian children had significantly higher mean BMI z-scores than the Gambian children (males: Italy 1.58, Gambia -1.44, P< or =0.0001; females: Italy 1.33, Gambia -1.42, P< or =0.0001) and significantly higher serum leptin concentrations (males: Italy 8.86 ng ml(-1), Gambia 1.78 ng ml(-1), P< or =0.0001; females: Italy 11.31 ng ml(-1), Gambia 2.22 ng ml(-1), P< or =0.0001). A significantly different relationship was observed between z-score of BMI and serum leptin levels in the Gambian and the Italian children for both boys and girls.

CONCLUSION

A different relationship exists between z-score of BMI and leptin levels in these two groups of children from very diverse ethnic backgrounds. Future studies using detailed measures of body composition and energy balance are needed to help understand this relationship.

Birth season and environmental influences on patterns of thymic growth in rural Gambian infants

AIM

In rural Gambia, birth season predicts infection-related adult mortality. Seasonal factors in early life may programme the immune system, possibly via an effect on thymic development. This study tested whether thymus size in rural Gambian infants is affected by birth season, defined as January-June (harvest, few infections) versus July-December (hungry, high infectious load).

METHODS

Thymic volume (thymic index) was assessed sonographically at 1, 8, 24 and 52 wk in 138 singleton infants born over 14 consecutive months. Growth and morbidity were regularly assessed.

RESULTS

Mean thymic index increased from 19.9 at 1 wk to 30.9 at 8 wk and 35.7 at 24 wk, then fell to 32.0 at 52 wk. Thymic index was associated with each preceding thymic index up to 24 wk. This tracking persisted after correcting for infant weight and month of measurement (p < 0.01). Thymic index at 1 wk was marginally but non-significantly lower in hungry season births (p = 0.06). Thymic index was lower in hungry season measurements; this effect persisted after adjusting for current weight and infection markers, and was strongest at 8 wk (p = 0.001).

CONCLUSION

These results describe a pattern of thymic growth followed by diminution in size. An infant's thymic index tracks despite changes in body weight and season. Thymic index was lower in the hungry season. This appears not to be explained by infection or nutritional status. A possible influence of trophic factors in breast milk merits investigation.

Impact of nutritional status on antibody responses to different vaccines in undernourished Gambian children

AIM

To test the efficacy of T-cell-dependent and T-cell-independent vaccines in rural Gambian children suffering from a range of energy/protein and micronutrient deficiencies.

METHODS

Nutritional status (anthropometry, haemoglobin, plasma leptin and micronutrient status) and response to two vaccinations (23 valent pneumococcal capsular polysaccharide vaccine, Pneumovax and the Human Diploid-Cell Rabies Vaccine) were assessed in 472 children aged 6 1/2 h to 9 1/2 y.

RESULTS

Anthropometry and micronutrient status (as z-scores against European reference values) indicated a range from moderate to severe levels of undernutrition [mean (interquartile range): weight-for-age z-score -1.58 (-2.18 to -0.95); height-for-age z-score -0.94 (-1.51 to -0.35); body-mass-index-for-age z-score -1.43 (-2.05 to -0.84); mid-upper arm circumference -1.41 (-1.72 to -1.13); leptin -1.06 (-1.10 to -1.03); haemoglobin (Hb) -0.30 (-1.18 to 0.79); zinc -1.29 (-2.42 to -0.55); vitamin C -0.01 (-1.18 to 1.15); retinol -1.33 (-1.97 to -0.77)]. A seasonal effect was observed in haemoglobin levels and in all micronutrients (with the exception of zinc and retinol) and in the response to vaccination. After adjusting for seasonality, age and gender, no consistent associations were found between any of the measures of nutritional status and the effectiveness of seroconversion to either of the vaccines.

CONCLUSION

The successful short-term seroconversion to whole inactivated viral and bacterial polysaccharide vaccines indicates that the processes leading to antibody secretion remain intact over a wide range of single and combined nutrient deficiencies.

Leptin, malnutrition, and immune response in rural Gambian children

BACKGROUND

The adipocyte derived hormone, leptin, has cytokine like function and may mediate the effects of starvation on immunity. Mice with congenital leptin deficiency (ob/ob) have small hypocellular thymuses and impaired cellular immunity. In humans leptin influences the differentiation of naïve and memory cells in vitro, and genetic leptin deficiency has been associated with an ill defined susceptibility to infection.

AIMS

To describe the in vivo relation of leptin and immune function in children.

METHODS

Fasting plasma leptin concentrations, immune function (T and B cell mediated vaccine responses and delayed type hypersensitivity), and mucosal function (dual sugar permeability test and salivary sIgA concentrations) were measured in a cohort of 472 moderately undernourished rural Gambian children.

RESULTS

Leptin concentrations correlated with body fat assessed by mid upper arm circumference or BMI for age Z scores, and were very low compared to well nourished European norms (males 1.8 v 11.1 ng/ml; females 2.4 v 13.8 ng/ml). No detectable relations were found between leptin concentrations and any of the measures of immune or mucosal function.

CONCLUSIONS

The data confirm that leptin acts as a peripheral signal of energy restriction, but do not support an association between fasting plasma leptin levels and immune function in children of this age.

Immune function in rural Gambian children is not related to season of birth, birth size, or maternal supplementation status

BACKGROUND

We previously showed that mortality from infectious diseases among young adults in rural Gambia is strongly correlated with the season of their birth. This suggests that early life insults that involve fetal malnutrition, exposure to natural toxins, or highly seasonal infections affecting the infant or pregnant mother cause permanent damage to the immune system. Excess mortality begins after puberty and has a maximal odds ratio of >10 for deaths between ages 25 and 50 y.

OBJECTIVE

We investigated the immune function of children according to birth weight, season of birth, and exposure to maternal dietary supplementation during pregnancy.

DESIGN

Immune function was measured in 472 prepubertal children aged 6.5-9.5 y from 28 villages in rural Gambia. The mothers of these children had been randomly assigned to a high-energy prenatal supplementation program, which significantly increased birth weight. This permitted supplementation status, birth weight, and season of birth to be investigated as exposure variables. The outcome variables tested were naive responses to rabies and pneumococcus vaccines, delayed-type hypersensitivity skin reactions, and mucosal defense (secretory immunoglobulin A and dual-sugar permeability).

RESULTS

Immune responses were strongly related to current age and sex, suggesting a high level of sensitivity, but were not consistently related to birth weight, season of birth, or maternal supplementation (control compared with intervention).

CONCLUSION

Events in early life did not predict a measurable defect in immune response within this cohort of rural Gambian children. It is possible that the early programming of immune function may be mediated through a defect in immunologic memory or early senescence rather than through impairment of early responses.

Cell signalling cascades regulating neuronal growth-promoting and inhibitory cues

During development of the nervous system, neurons extend axons over considerable distances in a highly stereospecific fashion in order to innervate their targets in an appropriate manner. This involves the recognition, by the axonal growth cone, of guidance cues that determine the pathway taken by the axons. These guidance cues can act to promote and/or repel growth cone advance, and they can act either locally or at a distance from their place of synthesis. The directed growth of axons is partly governed by cell adhesion molecules (CAMs) on the neuronal growth cone that bind to CAMs on the surface of other axons or non-neuronal cells. In vitro assays have established the importance of the CAMs (N-CAM, N-cadherin and the L1 glycoprotein) in promoting axonal growth over cells, such as Schwann cells, astrocytes and muscle cells. Strong evidence now exists implicating the fibroblast growth factor receptor tyrosine kinase as the primary signal transduction molecule in the CAM pathway. Cell adhesion molecules are important constituents of synapses, and CAMs appear to play important and diverse roles in regulating synaptic plasticity associated with learning and memory. Negative extracellular signals which physically direct neurite growth have also been described. The latter include the neuronal growth inhibitory proteins Nogo and myelin-associated glycoprotein, as well as the growth cone collapsing Semaphorins/neuropilins. Although less well characterised, evidence is now beginning to emerge describing a role for Rho kinase-mediated signalling in inhibition of neurite outgrowth. This review focuses on some of the major themes and ideas associated with this fast-moving field of neuroscience.