1179 4.5 TONNES OF FOOD WASTED ACROSS A HOSPITAL WARD: A SERVICE EVALUATION OF DIETARY INTAKE AND FOOD WASTE

Introduction

Malnutrition is a debilitating condition in hospitalised older people. There has been limited studies exploring dietary intake and oral nutritional supplement (ONS) compliance in these people. The purpose of this service evaluation was to observe daily energy and protein intake, plate waste and ONS compliance and to report food waste at ward level.

Methods

Three-day dietary (food-only) intake and plate waste of 19 older (≥ 65 years) people on a hospital trauma and orthopaedic (T&O) ward were assessed. Patients were categorised as ‘nutritionally well’ or ‘nutritionally vulnerable’ as per British Dietetics Association’s (BDA) Nutrition and Hydration Digest criteria. Dietary intake was calculated by a Dietitian and compared with adjusted BDA standards to exclude energy and protein from drinks. Ward plate and food trolley waste were weighed after lunch and supper for five days. Thirty-three ONS from 11 patients were collected before disposal and weighed.

Results

Mean age of the patients were 84 ± 9 years (9 female, and 10 male) with the most common injury hip fracture (68.4%). Mean (standard deviation, SD) intake for ‘nutritionally well’ was 1592 (257) kcal/day and 65.7(8.5) g/day protein and ‘nutritionally vulnerable’ (n= 15) 643 (354) kcal/day and 24.8 (14.0) g/day protein. Plate waste for ‘nutritionally well’ was 4.1 (5.8)% at main meals and 1.7 (3.4)% at pudding and for ‘nutritionally vulnerable’ 53.1 (26.6)% at main meals and 38.6 (32.2)% at pudding. Compliance to ONS was 28.3 (38.8)%. The combined mealtime plate waste weighed 6.2 (1.2) kg/day and food-trolley waste 6.2 (0.9) kg/day. This equates to approximately 4526kg/year (4.5T).

Conclusions

Energy and protein intake and compliance to ONS in older T&O patients is sub-optimal. Food waste is high and urgently needs addressing. Further, interventions are warranted to improve dietary intake in hospital and to explore the acceptability of alternative ONS food/drink styles.

POS0999 HIGHER CARDIOVASCULAR MORBIDITY SEEN IN MEN WITH LONGER DELAY TO THE DIAGNOSIS OF AXIAL SPONDYLOARTHRITIS

Background

Diagnostic delay in axial spondyloarthritis (axSpA) is a well-defined feature of the disease, despite increased awareness. Morbidity and mortality are higher in axSpA than the general population1. Much of this excess burden is due to increased comorbidity. However, the association between delayed diagnosis and increased comorbidity in this population is unknown.

Objectives

(1)Examine the relationship between delayed diagnosis and comorbidity in a large cohort of well characterised individuals with axSpA

(2)Assess the impact of sex on the relationship between diagnostic delay and comorbidity.

Methods

The Ankylosing Spondylitis Registry of Ireland (ASRI), a descriptive epidemiological study of the Irish axSpA population, provided the cohort for this study. A standardised clinical assessment was performed on each patient. Delay to diagnosis was calculated as age at diagnosis minus age at symptom onset. Comorbidities were considered as any condition present in addition to axial SpA, excluding extra-musculoskeletal manifestations (EMM). SPSS was used for statistical analysis, with appropriate tests used for normally and non-normally distributed data.

Results

Of the 913 included patients, 659 (72%) were male and mean age was 46 years (SD 13). Detailed baseline clinical and demographic characteristics are outlined in Table 1. Median delay to diagnosis was 5 (2, 12) years. Comorbidity was present in 37% (n=341) of the cohort, with hypertension the most prevalent (see Figure 1).

Table 1.

Baseline demographic and clinical characteristics

VariableAge, mean (SD)45.8 (12.6)Female, n (%)254 (27.8)Caucasian, n (%)819 (96.5)Ever Smoker, n (%)*527 (57.7)HLA-B27 positive, n (%)631 (89.9)Disease duration, median (25th,75th)17.1 (9.5, 27.8)Delay to diagnosis, median (25th, 75th)5.0 (2.0, 12.0)AAU, n (%)308 (34.4)PsO, n (%)150 (16.7)IBD, n (%)96 (10.7)Biologic use, n (%)628 (68.5)BASMI, mean (SD)3.6 (2.1)BASFI, mean (SD)3.4 (2.9)BASDAI, mean (SD)3.9 (2.4)HAQ, median (25th, 75th)0.38 (0.0, 0.9)

The median delay to diagnosis was significantly longer in those with ≥1 comorbidity compared to those with none (7 v 5 years, p<0.01). Hypertension (6 v 5 years, p=0.1) and cerebrovascular disease (10 v 5 years, p=0.03) were associated with a significantly longer delay to diagnosis, with a similar trend seen in those with hyperlipidaemia (7 v 5 years, p=0.09) and ischaemic heart disease (10 v 5 years, p=0.07). The delay to diagnosis was also longer in those that currently (7 v 5 years, p=0.03) or ever smoked (6 v 5 years, p<0.01). The delay to diagnosis was significantly longer in those with depression (9 v 5, p<0.05). The presence of EMM did not contribute to a delay to diagnosis, and there was no association with any categories of medication.

There was no significant difference in the median delay to diagnosis between females (5 v 6 years) for males. However, there were differences in the relationship between delay to diagnosis and the pattern of comorbidities between sexes. There was a significantly (p<0.05) longer delay to diagnosis in men with cerebrovascular disease (12 v 6 years), ischaemic heart disease (10 v 6 years) and diabetes (10 v 6 years), which wasn’t evident in females. Depression was associated with a longer delay to diagnosis in males (10 v 6 years, p<0.05), but not females (6 v 5 years, p=0.5).

Conclusion

Delay to diagnosis of axSpA was associated with a higher prevalence of comorbidities. This was particularly evident in men, with higher cardiovascular morbidity in those with a longer delay to diagnosis. Further research is needed to determine if shortening the delay to diagnosis would reduce the burden of cardiovascular morbidity.

References

[1]Chaudhary et al. All-Cause and Cause-Specific Mortality in Psoriatic Arthritis and Ankylosing Spondylitis: A Systematic Review and Meta-Analysis. Arthritis Care Res. 2021 Nov 17 (online).

Disclosure of Interests

None declared

POS1001 CURRENT SMOKING IS ASSOCIATED WITH LOWER RISK OF UVEITIS AND PERIPHERAL ARTHRITIS IN MALES WITH AXIAL SPONDYLOARTHRITIS

Background

The associations between smoking and extra-axial manifestations of axial spondyloarthritis (axSpA) are inadequately described. Previous observational studies have demonstrated smoking as protective against some but not other manifestations. However, the impact of sex on these associations is unknown.

Objectives

Using a large descriptive epidemiological dataset, we performed a sex-stratified analysis of the association between smoking status and extra-axial manifestations in axSpA.

Methods

This study was carried out within the framework of ASRI (Ankylosing Spondylitis Registry of Ireland), a descriptive epidemiological study of the axSpA population of Ireland. A standardised clinical assessment was performed on each patient, collecting demographic and clinical data. Smoking status was characterised as current, previous or never. The number of cigarettes per day, plus number of years smoking was also collected. Data on the following extra-axial manifestations was collected: arthritis, enthesitis, dactylitis, acute anterior uveitis (AAU), psoriasis (PsO), inflammatory bowel disease (IBD). Standardised measures of disease severity were also collected. Separate logistic regression models were used to define the association between extra-axial manifestations and smoking, controlling for potential confounders. SPSS was used for statistical analysis.

Results

Smoking data was available for 913 out of the 917 axSpA individuals with data in ASRI (mean age 46 (SD 13) years, disease duration 19 (SD 12) years, 72% male, 97% Caucasian). Twenty eight percent (n=259) were current smokers, 29% (n=268) were past smokers and 42% (n=386) were never smokers. Of the current smokers, the mean number of cigarettes per day was 12 (SD 7) and number of years smoking was 22 (SD 12). Thirty one percent had peripheral arthritis, 7% had dactylitis, 18% had enthesitis, 34% had AAU, 17% had psoriasis and 11% had IBD.

Current smokers had a significantly lower prevalence of arthritis and uveitis than past or non-smokers (see Table 1). A sex-stratified analysis was performed. There was no association between smoking status and any extra-axial manifestation in females. However, current smoking was associated with lower prevalence of arthritis in males compared to past or non-smokers (22% v 36% v 42%, p=0.002). A similar pattern was seen for uveitis, where male current smokers had a lower prevalence than non-smokers (24% v 38%, p=0.01). In contrast, psoriasis was more prevalent in men who were current smokers compared to non-smokers (18% v 12%, p=0.01), with no difference seen in females. There was no association with number of cigarettes smoked or number of years smoking.

Table 1.

Association between smoking status and extra-axial manifestations in axSpA.

AxSpA cohortCurrent smokerPast smokerNon-smokerArthritis30.9%22.4%a35.5%b33.3%bDactylitis6.7%5.5%a6.7% a7.4% aEnthesitis18.1%17.4% a16.2% a19.9% aUveitis34.3%27.4%a35.0%b38.6%bPsoriasis16.7%18.5% a19.3% a13.8% aInflammatory bowel disease10.7%9.9% a13.2% a9.5% a

Different subscript letters denote significant (p<0.05) differences between groups. Significant values highlighted in bold.

There was no association between smoking status and disease severity by subjective or objective measures, either for the cohort as a whole or by sex.

When compared to non- or ex-smokers and controlled for potential confounders including sex, age, biologic use, the association remained only between current smokers and lower risk of uveitis (OR 0.68, 95% CI 0.49 to 0.96) and arthritis (OR 0.62, 95% CI 0.43 to 0.88), in separate logistic regression models. The association between current smoking and increased prevalence of psoriasis in males did not remain significant once controlled for confounders (OR 1.10, 96% CI 0.73 to 1.65).

Conclusion

We demonstrated that current smoking is independently associated with a lower risk of uveitis and arthritis in males with axSpA, but not females. More research is needed to further investigate this paradoxical finding.

Disclosure of Interests

None declared

IgM in human immunity to Plasmodium falciparum malaria

Most studies on human immunity to malaria have focused on the roles of immunoglobulin G (IgG), whereas the roles of IgM remain undefined. Analyzing multiple human cohorts to assess the dynamics of malaria-specific IgM during experimentally induced and naturally acquired malaria, we identified IgM activity against blood-stage parasites. We found that merozoite-specific IgM appears rapidly in Plasmodium falciparum infection and is prominent during malaria in children and adults with lifetime exposure, together with IgG. Unexpectedly, IgM persisted for extended periods of time; we found no difference in decay of merozoite-specific IgM over time compared to that of IgG. IgM blocked merozoite invasion of red blood cells in a complement-dependent manner. IgM was also associated with significantly reduced risk of clinical malaria in a longitudinal cohort of children. These findings suggest that merozoite-specific IgM is an important functional and long-lived antibody response targeting blood-stage malaria parasites that contributes to malaria immunity.

A manually annotated Actinidia chinensis var. chinensis (kiwifruit) genome highlights the challenges associated with draft genomes and gene prediction in plants

Background

Most published genome sequences are drafts, and most are dominated by computational gene prediction. Draft genomes typically incorporate considerable sequence data that are not assigned to chromosomes, and predicted genes without quality confidence measures. The current Actinidia chinensis (kiwifruit) ‘Hongyang’ draft genome has 164 Mb of sequences unassigned to pseudo-chromosomes, and omissions have been identified in the gene models.

Results

A second genome of an A. chinensis (genotype Red5) was fully sequenced. This new sequence resulted in a 554.0 Mb assembly with all but 6 Mb assigned to pseudo-chromosomes. Pseudo-chromosomal comparisons showed a considerable number of translocation events have occurred following a whole genome duplication (WGD) event some consistent with centromeric Robertsonian-like translocations. RNA sequencing data from 12 tissues and ab initio analysis informed a genome-wide manual annotation, using the WebApollo tool. In total, 33,044 gene loci represented by 33,123 isoforms were identified, named and tagged for quality of evidential support. Of these 3114 (9.4%) were identical to a protein within ‘Hongyang’ The Kiwifruit Information Resource (KIR v2). Some proportion of the differences will be varietal polymorphisms. However, as most computationally predicted Red5 models required manual re-annotation this proportion is expected to be small. The quality of the new gene models was tested by fully sequencing 550 cloned ‘Hort16A’ cDNAs and comparing with the predicted protein models for Red5 and both the original ‘Hongyang’ assembly and the revised annotation from KIR v2. Only 48.9% and 63.5% of the cDNAs had a match with 90% identity or better to the original and revised ‘Hongyang’ annotation, respectively, compared with 90.9% to the Red5 models.

Conclusions

Our study highlights the need to take a cautious approach to draft genomes and computationally predicted genes. Our use of the manual annotation tool WebApollo facilitated manual checking and correction of gene models enabling improvement of computational prediction. This utility was especially relevant for certain types of gene families such as the EXPANSIN like genes. Finally, this high quality gene set will supply the kiwifruit and general plant community with a new tool for genomics and other comparative analysis.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-4656-3) contains supplementary material, which is available to authorized users.

Far-infrared observations of a massive cluster forming in the Monoceros R2 filament hub⋆

We present far-infrared observations of Monoceros R2 (a giant molecular cloud at approximately 830 pc distance, containing several sites of active star formation), as observed at 70 μm, 160 μm, 250 μm, 350 μm, and 500 μm by the Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) instruments on the Herschel Space Observatory as part of the Herschel imaging survey of OB young stellar objects (HOBYS) Key programme. The Herschel data are complemented by SCUBA-2 data in the submillimetre range, and WISE and Spitzer data in the mid-infrared. In addition, C18O data from the IRAM 30-m Telescope are presented, and used for kinematic information. Sources were extracted from the maps with getsources, and from the fluxes measured, spectral energy distributions were constructed, allowing measurements of source mass and dust temperature. Of 177 Herschel sources robustly detected in the region (a detection with high signal-to-noise and low axis ratio at multiple wavelengths), including protostars and starless cores, 29 are found in a filamentary hub at the centre of the region (a little over 1% of the observed area). These objects are on average smaller, more massive, and more luminous than those in the surrounding regions (which together suggest that they are at a later stage of evolution), a result that cannot be explained entirely by selection effects. These results suggest a picture in which the hub may have begun star formation at a point significantly earlier than the outer regions, possibly forming as a result of feedback from earlier star formation. Furthermore, the hub may be sustaining its star formation by accreting material from the surrounding filaments.

Genetic Diversity and Protective Efficacy of the RTS,S/AS01 Malaria Vaccine

BACKGROUND

The RTS,S/AS01 vaccine targets the circumsporozoite protein of Plasmodium falciparum and has partial protective efficacy against clinical and severe malaria disease in infants and children. We investigated whether the vaccine efficacy was specific to certain parasite genotypes at the circumsporozoite protein locus.

METHODS

We used polymerase chain reaction-based next-generation sequencing of DNA extracted from samples from 4985 participants to survey circumsporozoite protein polymorphisms. We evaluated the effect that polymorphic positions and haplotypic regions within the circumsporozoite protein had on vaccine efficacy against first episodes of clinical malaria within 1 year after vaccination.

RESULTS

In the per-protocol group of 4577 RTS,S/AS01-vaccinated participants and 2335 control-vaccinated participants who were 5 to 17 months of age, the 1-year cumulative vaccine efficacy was 50.3% (95% confidence interval [CI], 34.6 to 62.3) against clinical malaria in which parasites matched the vaccine in the entire circumsporozoite protein C-terminal (139 infections), as compared with 33.4% (95% CI, 29.3 to 37.2) against mismatched malaria (1951 infections) (P=0.04 for differential vaccine efficacy). The vaccine efficacy based on the hazard ratio was 62.7% (95% CI, 51.6 to 71.3) against matched infections versus 54.2% (95% CI, 49.9 to 58.1) against mismatched infections (P=0.06). In the group of infants 6 to 12 weeks of age, there was no evidence of differential allele-specific vaccine efficacy.

CONCLUSIONS

These results suggest that among children 5 to 17 months of age, the RTS,S vaccine has greater activity against malaria parasites with the matched circumsporozoite protein allele than against mismatched malaria. The overall vaccine efficacy in this age category will depend on the proportion of matched alleles in the local parasite population; in this trial, less than 10% of parasites had matched alleles. (Funded by the National Institutes of Health and others.).

An audit of HIV care in English prisons

Previous studies have highlighted disparities in care and outcomes in HIV-positive prisoners compared to HIV-positive individuals in the population. We audited clinical outcomes of HIV-positive prisoners accessing care in 2011. Public Health England were notified of 161 prisoners with HIV in the time period studied. Audit proformas were sent to clinics reporting prisoners to the genitourinary medicine clinic activity dataset in 2011. Thirty-two clinics responded. Data for 151 HIV-positive prisoners were reported by 12 clinics, with the other clinics not reporting any prisoners. Outcomes were compared to a previous audit, British HIV Association (BHIVA) and the National AIDS Trust guidelines. Initial CD4 counts were available for 101 patients, of which 42/101 had CD4 <350 cells/mm(3). At reception, viral load data were available for 95 patients, of which 74 were on antiretroviral therapy. Of these, 50/74 (68%) had VL <40 copies/ml. Fifty-one per cent of those on highly active antiretroviral therapy were seen in a specialist clinic less than four weeks after reception. Urgency of referral to a specialist HIV clinic was not related to CD4 or viral load. Twenty-two per cent had hepatitis C co-infection. Clinical outcomes have improved since the last audit but further opportunities exist to optimise care in prisons.

Biochemical and structural characterisation of dehydroquinate synthase from the New Zealand kiwifruit Actinidia chinensis

One of the novel aspects of kiwifruit is the presence of a high level of quinic acid which contributes to the flavour of the fruit. Quinic acid metabolism intersects with the shikimate pathway, which is responsible for the de novo biosynthesis of primary and secondary aromatic metabolites. The gene encoding the enzyme which catalyses the second step of the shikimate pathway, dehydroquinate synthase (DHQS), from the New Zealand kiwifruit Actinidia chinensis was identified, cloned and expressed. A. chinensis DHQS was activated by divalent metal ions, and was found to require NAD(+) for catalysis. The protein was crystallised and the structure was solved, revealing a homodimeric protein. Each monomer has a NAD(+) binding site nestled between the distinct N- and C-terminal domains. In contrast to other microbial DHQSs, which show an open conformation in the absence of active site ligands, A. chinensis DHQS adopts a closed conformation. This is the first report of the structure of a DHQS from a plant source.

The clinical effectiveness and cost-effectiveness of primary stroke prevention in children with sickle cell disease: a systematic review and economic evaluation

BACKGROUND

Sickle cell disease (SCD) is a recessive genetic blood disorder, caused by a mutation in the β-globin gene. For children with SCD, the risk of stroke is estimated to be up to 250 times higher than in the general childhood population. Transcranial Doppler (TCD) ultrasonography is a non-invasive technique which measures local blood velocity in the proximal portions of large intracranial arteries. Screening with TCD ultrasonography identifies individuals with high cerebral blood velocity; these children are at the highest risk of stroke. A number of primary stroke prevention strategies are currently used in clinical practice in the UK including blood transfusion, treatment with hydroxycarbamide and bone marrow transplantation (BMT). No reviews have yet assessed the clinical effectiveness and cost effectiveness of primary stroke prevention strategies in children with SCD identified to be at high risk of stroke using TCD ultrasonography.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of primary stroke prevention treatments for children with SCD who are identified (using TCD ultrasonography) to be at high risk of stroke.

DATA SOURCES

Electronic databases were searched from inception up to May 2011, including the Cochrane Database of Systematic Reviews (CDSR), the Cochrane Central Register of Controlled Trials (CENTRAL), the Database of Abstracts of Reviews of Effects (DARE), EMBASE, the Health Technology Assessment (HTA) database, ISI Web of Science Proceedings, ISI Web of Science Citation Index, the NHS Economic Evaluation Database (NHS EED) and MEDLINE.

REVIEW METHODS

The assessment was conducted according to accepted procedures for conducting and reporting systematic reviews and economic evaluations. A de novo Markov model was developed to determine the cost-effectiveness of TCD ultrasonography and blood transfusion, where clinically appropriate, in patients with SCD.

RESULTS

Two randomised controlled trials met the inclusion criteria involving a study population of 209 participants. One compared blood transfusion with standard care for children who are identified as being at high risk of stroke using TCD ultrasonography. In this trial, one patient in the transfusion group had a stroke (1/63) compared with 11 children in the standard care group (11/67). The other trial assessed the impact of halting chronic transfusion in patients with SCD. Sixteen patients in the transfusion-halted group had an event (16/41) (two patients experienced stroke and 14 reverted to abnormal TCD velocity); there were no events in the continued-transfusion group (0/38). No meta-analyses of these trials were undertaken. No relevant economic evaluations were identified for inclusion in the review. The de novo modelling suggests that blood transfusions plus TCD scans (compared with just TCD scans) for patients with SCD at high risk of stroke, aged ≥ 2 years, may be good value for money. The intervention has an incremental cost-effectiveness ratio of £24,075 per quality-adjusted life-year gained, and helps avoid 68 strokes over the lifetime of a population of 1000 patients. The intervention costs an additional £13,751 per patient and generates 0.6 extra years of life in full health per patient. The data available for the economic analysis are limited. Sensitivity analyses and validation against existing data and expert opinion provide some reassurance that the conclusion of the model is reliable but further research is required to validate these findings.

LIMITATIONS

The main limitations relate to the availability of published clinical data; no completed randomised controlled trials were identified which evaluated the efficacy of either BMT or hydroxycarbamide for primary stroke prevention. Both the clinical and cost data available for use in the economic analysis are limited. Sensitivity analyses and validation against existing data and expert opinion provide some reassurance that the conclusions of the model are reliable, but further research is required to validate these findings.

CONCLUSIONS

The use of TCD ultrasonography to identify children at high risk of stroke, and treating these children with prophylactic blood transfusions, appears to be both clinically effective and cost-effective compared with TCD ultrasonography only. However, given the limitations in the data available, further research is required to verify this conclusion. Several research recommendations can be proposed from this review. Clinically, more research is needed to assess the effects and optimal duration of long-term blood transfusion and the potential role of hydroxycarbamide in primary stroke prevention. From an economics perspective, further research is required to generate more robust data on which to base estimates of cost-effectiveness or against which model outputs can be calibrated. More data are required to explain how utility weights vary with age, transfusions and strokes. Research is also needed around the cost of paediatric stroke in the UK.

STUDY REGISTRATION

PROSPERO CRD42011001496.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Rapid increase in gonorrhoea and syphilis diagnoses in England in 2011

There has been a rapid rise in the number of gonorrhoea and syphilis diagnoses in England during 2011, an increase of 25% and 10% respectively. Large increases of both gonorrhoea (61%) and syphilis (28%) were observed among men who have sex with men. Although these rises can partly be attributed to increased testing, ongoing high-levels of unsafe sexual behaviour probably contributed to the rise. The rise in gonorrhoea rates is worrying in an era of decreased susceptibility to treatments.

Rapid increase in gonorrhoea and syphilis diagnoses in England in 2011

There has been a rapid rise in the number of gonorrhoea and syphilis diagnoses in England during 2011, an increase of 25% and 10% respectively. Large increases of both gonorrhoea (61%) and syphilis (28%) were observed among men who have sex with men. Although these rises can partly be attributed to increased testing, ongoing high-levels of unsafe sexual behaviour probably contributed to the rise. The rise in gonorrhoea rates is worrying in an era of decreased susceptibility to treatments.

Allele-specific antibodies to Plasmodium falciparum merozoite surface protein-2 and protection against clinical malaria

IgG and IgG3 antibodies to merozoite surface protein-2 (MSP-2) of Plasmodium falciparum have been associated with protection from clinical malaria in independent studies. We determined whether this protection was allele-specific by testing whether children who developed clinical malaria lacked IgG/IgG3 antibodies specific to the dominant msp2 parasite genotypes detected during clinical episodes. We analysed pre-existing IgG and IgG1/IgG3 antibodies to antigens representing the major dimorphic types of MSP-2 by ELISA. We used quantitative real-time PCR to determine the dominant msp2 alleles in parasites detected in clinical episodes. Over half (55%, 80/146) of infections contained both allelic types. Single or dominant IC1- and FC27-like alleles were detected in 46% and 42% of infections respectively, and both types were equally dominant in 12%. High levels of IgG/IgG3 antibodies to the FC27-like antigen were not significantly associated with a lower likelihood of clinical episodes caused by parasites bearing FC27-like compared to IC1-like alleles, and vice versa for IgG/IgG3 antibodies to the IC1-like antigen. These findings were supported by competition ELISAs which demonstrated the presence of IgG antibodies to allele-specific epitopes within both antigens. Thus, even for this well-studied antigen, the importance of an allele-specific component of naturally acquired protective immunity to malaria remains to be confirmed.

The selection landscape of malaria parasites

Malaria parasites have to survive and transmit within a highly selective and ever-changing host environment. Because immunity to malaria is nonsterilizing and builds up slowly through repeated infections, commonly the parasite invades a host that is immunologically and physiologically different from its previous host. During the course of infection, the parasite must also keep pace with changes in host immune responses and red-blood-cell physiology. Here, we describe the "selection landscape" of the most virulent of the human malaria parasites, Plasmodium falciparum, and the adaptive mechanisms it uses to navigate through that landscape. Taking a cost-benefit view of parasite fitness, we consider the evolutionary outcomes of the most important forces of selection operating on the parasite, namely immunity, host death, drugs, mosquito availability, and coinfection. Given the huge potential for malaria parasite evolution in the context of the recently renewed effort to eradicate malaria, a deeper understanding of P. falciparum adaptation is essential.

Report of a consultation on the optimization of clinical challenge trials for evaluation of candidate blood stage malaria vaccines, 18-19 March 2009, Bethesda, MD, USA

Development and optimization of first generation malaria vaccine candidates has been facilitated by the existence of a well-established Plasmodium falciparum clinical challenge model in which infectious sporozoites are administered to human subjects via mosquito bite. While ideal for testing pre-erythrocytic stage vaccines, some researchers believe that the sporozoite challenge model is less appropriate for testing blood stage vaccines. Here we report a consultation, co-sponsored by PATH MVI, USAID, EMVI and WHO, where scientists from all institutions globally that have conducted such clinical challenges in recent years and representatives from regulatory agencies and funding agencies met to discuss clinical malaria challenge models. Participants discussed strengthening and harmonizing the sporozoite challenge model and considered the pros and cons of further developing a blood stage challenge possibly better suited for evaluating the efficacy of blood stage vaccines. This report summarizes major findings and recommendations, including an update on the Plasmodium vivax clinical challenge model, the prospects for performing experimental challenge trials in malaria endemic countries and an update on clinical safety data. While the focus of the meeting was on the optimization of clinical challenge models for evaluation of blood stage candidate malaria vaccines, many of the considerations are relevant for the application of challenge trials to other purposes.

Use of the H3 receptor antagonist radioligand [3H]-A-349821 to reveal in vivo receptor occupancy of cognition enhancing H3 receptor antagonists

BACKGROUND AND PURPOSE

The histamine H3 receptor antagonist radioligand [3H]-A-349821 was characterized as a radiotracer for assessing in vivo receptor occupancy by H3 receptor antagonists that affect behaviour. This model was established as an alternative to ex vivo binding methods, for relating antagonist H3 receptor occupancy to blood levels and efficacy in preclinical models.

EXPERIMENTAL APPROACH

In vivo cerebral cortical H3 receptor occupancy by [3H]-A-349821 was determined in rats from differences in [3H]-A-349821 levels in the isolated cortex and cerebellum, a brain region with low levels of H3 receptors. Comparisons were made to relate antagonist H3 receptor occupancy to blood levels and efficacy in a preclinical model of cognition, the five-trial inhibitory avoidance response in rat pups.

KEY RESULTS

In adult rats, [3H]-A-349821, 1.5 microg x kg(-1), penetrated into the brain and cleared more rapidly from cerebellum than cortex; optimally, [3H]-A-349821 levels were twofold higher in the latter. With increasing [3H]-A-349821 doses, cortical H3 receptor occupancy was saturable with a binding capacity consistent with in vitro binding in cortex membranes. In studies using tracer [3H]-A-349821 doses, ABT-239 and other H3 receptor antagonists inhibited H3 receptor occupancy by [3H]-A-349821 in a dose-dependent manner. Blood levels of the antagonists corresponding to H3 receptor occupancy were consistent with blood levels associated with efficacy in the five-trial inhibitory avoidance response.

CONCLUSIONS AND IMPLICATIONS

When employed as an occupancy radiotracer, [3H]-A-349821 provided valid measurements of in vivo H3 receptor occupancy, which may be helpful in guiding and interpreting clinical studies of H3 receptor antagonists.

Prevalence of serum neutralizing antibodies against chimpanzee adenovirus 63 and human adenovirus 5 in Kenyan children, in the context of vaccine vector efficacy

Vaccination against Plasmodium falciparum malaria could reduce the worldwide burden of this disease, and decrease its high mortality in children. Replication-defective recombinant adenovirus vectors carrying P. falciparum epitopes may be useful as part of a vaccine that raises cellular immunity to the pre-erythrocytic stage of malaria infection. However, existing immunity to the adenovirus vector results in antibody-mediated neutralization of the vaccine vector, and reduced vaccine immunogenicity. Our aim was to examine a population of children who are at risk from P. falciparum malaria for neutralizing immunity to replication-deficient recombinant chimpanzee adenovirus 63 vector (AdC63), compared to human adenovirus 5 vector (AdHu5). We measured 50% and 90% vector neutralization titers in 200 individual sera, taken from a cohort of children from Kenya, using a secreted alkaline phosphatase neutralization assay. We found that 23% of the children (aged 1-6 years) had high-titer neutralizing antibodies to AdHu5, and 4% had high-titer neutralizing antibodies to AdC63. Immunity to both vectors was age-dependent. Low-level neutralization of AdC63 was significantly less frequent than AdHu5 neutralization at the 90% neutralization level. We conclude that AdC63 may be a useful vector as part of a prime-boost malaria vaccine in children.

The impact of primary health care on malaria morbidity--defining access by disease burden

OBJECTIVES

Primary care facilities are increasingly becoming the focal point for distribution of malaria intervention strategies, but physical access to these facilities may limit the extent to which communities can be reached. To investigate the impact of travel time to primary care on the incidence of hospitalized malaria episodes in a rural district in Kenya.

METHODS

The incidence of hospitalized malaria in a population under continuous demographic surveillance was recorded over 3 years. The time to travel to the nearest primary health care facility was calculated for every child between birth and 5 years of age and trends in incidence of hospitalized malaria as a function of travel time were evaluated.

RESULTS

The incidence of hospitalized malaria more than doubled as travel time to the nearest primary care facility increased from 10 min to 2 h. Good access to primary health facilities may reduce the burden of disease by as much as 66%.

CONCLUSIONS

Our results highlight both the potential of the primary health care system in reaching those most at risk and reducing the disease burden. Insufficient access is an important risk factor, one that may be inequitably distributed to the poorest households.

Malaria and Nutritional Status in Children Living on the Coast of Kenya

The relationship between malnutrition and malaria is controversial. On one hand, malaria may cause malnutrition, while on the other, malnutrition itself may modulate susceptibility to the disease. We investigated the association between Plasmodium falciparum malaria and malnutrition in a cohort of children living on the coast of Kenya. The study involved longitudinal follow‐up for clinical malaria episodes and anthropometric measurements at four cross‐sectional surveys. We used Poisson regression analysis to investigate the association between malaria and nutritional status. Compared to baseline (children with a WAZ or HAZ score of ≥−2), the crude incidence rate ratios (IRRs) for malaria in children with low HAZ or WAZ scores (<−2) during the period prior to assessment were 1.17 (95% CI 0.91–1.50; 0 = 0.21) and 0.94 (0.71–1.25; 0.67), respectively, suggesting no association between malaria and the subsequent development of PEM. However, we found that age was acting as an effect modifier in the association between malaria and malnutrition. The IRR for malaria in children 0–2 years old who were subsequently characterized as wasted was 1.65 (1.10–2.20; P = 0.01), and a significant overall relationship between malaria and low‐HAZ was found on regression analysis when adjusting for the interaction with age (IRR 1.89; 1.01–3.53; P < 0.05). Although children living on the coast of Kenya continue to suffer clinical episodes of uncomplicated malaria throughout their first decade, the association between malaria and malnutrition appears to be limited to the first 2 years of life.

Variation in the ICAM1 gene is not associated with severe malaria phenotypes

Evidence from autopsy and in vitro binding studies suggests that adhesion of erythrocytes infected with Plasmodium falciparum to the human host intercellular adhesion molecule (ICAM)-1 receptor is important in the pathogenesis of severe malaria. Previous association studies between polymorphisms in the ICAM1 gene and susceptibility to severe malarial phenotypes have been inconclusive and often contradictory. We performed genetic association studies with 15 single nucleotide polymorphisms (SNPs) around the ICAM1 locus. All SNPs were screened in a family study of 1071 trios from The Gambia, Malawi and Kenya. Two key non-synonymous SNPs with previously reported associations, rs5491 (K56M or 'ICAM-1(Kilifi)') and rs5498 (K469E), were tested in an additional 708 Gambian trios and a case-control study of 4058 individuals. None of the polymorphisms were associated with severe malaria phenotypes. Pooled results across our studies for ICAM-1(Kilifi) were, in severe malaria, odds ratio (OR) 1.02, 95% confidence interval (CI) 0.96-1.09, P=0.54, and cerebral malaria OR 1.07, CI 0.97-1.17, P=0.17. We assess the available epidemiological, population genetic and functional evidence that links ICAM-1(Kilifi) to severe malaria susceptibility.

Failure to respond to the surface of Plasmodium falciparum infected erythrocytes predicts susceptibility to clinical malaria amongst African children

Following infection with Plasmodium falciparum malaria, children in endemic areas develop antibodies specific to antigens on the parasite-infected red cell surface of the infecting isolate, antibodies associated with protection against subsequent infection with that isolate. In some circumstances induction of antibodies to heterologous parasite isolates also occurs and this has been suggested as evidence for cross-reactivity of responses against the erythrocyte surface. The role of these relatively cross-reactive antibodies in protection from clinical malaria is currently unknown. We studied the incidence of clinical malaria amongst children living on the coast of Kenya through one high transmission season. By categorising individuals according to their pre-season parasite status and antibody response to the surface of erythrocytes infected with four parasite isolates we were able to identify a group of children, those who failed to make a concomitant antibody response in the presence of an asymptomatic parasitaemia, at increased susceptibility to clinical malaria in the subsequent 6 months. The fact that this susceptible group was identified regardless of the parasite isolate tested infers a cross-reactive or conserved target is present on the surface of infected erythrocytes. Identification of this target will significantly aid understanding of naturally acquired immunity to clinical malaria amongst children in endemic areas.

Positive replication and linkage disequilibrium mapping of the chromosome 21q22.1 malaria susceptibility locus

Four cytokine receptor genes are located on Chr21q22.11, encoding the alpha and beta subunits of the interferon-alpha receptor (IFNAR1 and IFNAR2), the beta subunit of the interleukin 10 receptor (IL10RB) and the second subunit of the interferon-gamma receptor (IFNGR2). We previously reported that two variants in IFNAR1 were associated with susceptibility to malaria in Gambians. We now present an extensive fine-scale mapping of the associated region utilizing 45 additional genetic markers obtained from public databases and by sequencing a 44 kb region in and around the IFNAR1 gene in 24 Gambian children (12 cases/12 controls). Within the IFNAR1 gene, a newly studied C --> G single-nucleotide polymorphism (IFNAR1 272354c-g) at position -576 relative to the transcription start was found to be more strongly associated with susceptibility to severe malaria. Association was observed in three populations: in Gambian (P=0.002), Kenyan (P=0.022) and Vietnamese (P=0.005) case-control studies. When all three studies were combined, using the Mantel-Haenszel test, the presence of IFNAR1 -576G was associated with a substantially elevated risk of severe malaria (N=2444, OR=1.38, 95% CI: 1.17-1.64; P=1.7 x 10(-4)). This study builds on previous work to further highlight the importance of the type-I interferon pathway in malaria susceptibility and illustrates the utility of typing SNPs within regions of high linkage disequilibrium in multiple populations to confirm initial positive associations.

Naturally acquired antibodies to polymorphic and conserved epitopes of Plasmodium falciparum merozoite surface protein 3

Many studies on the role of merozoite surface protein 3 (MSP3) in immunity against malaria have focused on a conserved section of MSP3. New evidence suggests that polymorphic sequences within MSP3 are under immune selection. We report a detailed analysis of naturally-acquired antibodies to allele-specific and conserved parts of MSP3 in a Kenyan cohort. Indirect and competition ELISA to heterologous recombinant MSP3 proteins were used for antibody assays, and parasites were genotyped for msp3 alleles. Antibody reactivity to allele-specific and conserved epitopes of MSP3 was heterogenous between individuals. Overall, the prevalence of allele-specific antibody reactivity was significantly higher (3D7-specific 54%, K1-specific 41%) than that to a recombinant protein representing a conserved portion of C-terminal MSP3 (24%, P < 0·01). The most abundant IgG subclass was IgG3, followed by IgG1. Allele-specific reactivity to the K1-type of MSP3 was associated with a lower risk of clinical malaria episodes during a 6-month follow-up in individuals who were parasitized at the start of the malaria transmission season (Relative risk 0·41 with 95% confidence interval 0·20–0·81, P = 0·011). The potential importance of allele-specific immunity to MSP3 should be considered in addition to immunity to conserved epitopes, in the development of an MSP3 malaria vaccine.

Iron-shortage-induced increase in citric acid content and reduction of cytosolic aconitase activity in Citrus fruit vesicles and calli

Aconitase, which catalyses the conversion of citrate into isocitrate, requires Fe for its activity. The yeast and animal enzyme loses its enzymatic activity under Fe shortage and binds to RNA of genes involved in Fe homeostasis, altering their expression. Thus, the enzyme provides a regulatory link between organic acid metabolism and Fe cellular status. Roots and leaves of Fe-deficient plants show induction in organic acids, especially citrate. Although no RNA-binding activity has been so far demonstrated for the plant aconitase, whether alternations in enzyme activity by Fe could play a role in this induction remain unanswered. This question was investigated in lemon fruit [Citrus limon (L.) Burm var Eureka], characterized by the accumulation of citrate to about 0.3 M in the juice vesicles cells (pulp). Calli and isolated juice vesicles showed two- to three-fold induction in citrate level when subjected to Fe shortage. The mRNA level of aconitase exhibited no changes under reduced Fe concentrations. Analysis of aconitase isozymes demonstrated that out of two aconitase isozymes, typically detected in citrus fruit, only the cytosolic form displayed a reduced activity under low Fe concentrations. Our data support the notion of a limited Fe-availability-induced reduction in cytosolic aconitase, resulting in a slower rate of citrate breakdown and a concomitant increase in citrate levels.

P2X7-related modulation of pathological nociception in rats

Growing evidence supports a role for the immune system in the induction and maintenance of chronic pain. ATP is a key neurotransmitter in this process. Recent studies demonstrate that the glial ATP receptor, P2X7, contributes to the modulation of pathological pain. To further delineate the endogenous mechanisms that are involved in P2X7-related antinociception, we utilized a selective P2X7 receptor antagonist, A-438079, in a series of in vivo and in vitro experiments. Injection of A-438079 (10-300 micromol/kg, i.p.) was anti-allodynic in three different rat models of neuropathic pain and it attenuated formalin-induced nocifensive behaviors. Using in vivo electrophysiology, A-438079 (80 micromol/kg, i.v.) reduced noxious and innocuous evoked activity of different classes of spinal neurons (low threshold, nociceptive specific, wide dynamic range) in neuropathic rats. The effects of A-438079 on evoked firing were diminished or absent in sham rats. Spontaneous activity of all classes of spinal neurons was also significantly reduced by A-438079 in neuropathic but not sham rats. In vitro, A-438079 (1 microM) blocked agonist-induced (2,3-O-(4-benzoylbenzoyl)-ATP, 30 microM) current in non-neuronal cells taken from the vicinity of the dorsal root ganglia. Furthermore, A-438079 dose-dependently (0.3-3 microM) decreased the quantity of the cytokine, interleukin-1beta, released from peripheral macrophages. Thus, ATP, acting through the P2X7 receptor, exerts a wide-ranging influence on spinal neuronal activity following a chronic injury. Antagonism of the P2X7 receptor can in turn modulate central sensitization and produce antinociception in animal models of pathological pain. These effects are likely mediated through immuno-neural interactions that affect the release of endogenous cytokines.

Sickle cell disease in Africa: burden and research priorities

Sickle cell disease (SCD) has recently been recognised as a problem of major public-health significance by the World Health Organization. Despite the fact that >70% of sufferers live in Africa, expenditure on the related care and research in the continent is negligible, and most advances in the understanding and management of this condition have been based on research conducted in the North. In order to target limited resources, African countries need to focus research and interventions on areas that will lead to the maximum impact. This review details the epidemiological and clinical background of SCD, with an emphasis on Africa, before identifying the research priorities that will provide the necessary evidence base for improving the management of African patients. Malaria, bacterial and viral infections and cerebrovascular accidents are areas in which further research may lead to a significant improvement in SCD-related morbidity and mortality. As patients with high concentrations of foetal haemoglobin (HbF) appear to be protected from all but mild SCD, the various factors and pharmacological agents that might increase HbF levels need to be assessed in Africa, as options for interventions that would improve quality of life and reduce mortality.

Elevated plasma urokinase receptor predicts low birth weight in maternal malaria

The blood level of soluble urokinase receptor (suPAR) is increased and associated with a poor clinical or fatal outcome in children with acute malaria. This study hypothesized that the suPAR level would be associated with foetal outcome in maternal malaria. suPAR was measured by ELISA in maternal and cord plasma samples taken during delivery in 253 pregnant Kenyan women stratified according to placental histology: no malaria infection (non-infected), active or active-chronic infection (actively infected) or past-chronic infection (past-infected). Maternal-suPAR was higher in actively infected women (median 3.93 (IQR 2.92-5.29) ng/mL) compared with non-infected (median 2.78 (IQR 1.86-3.87) ng/mL, P = 0.001) and past-infected (median 2.67 (IQR 1.94-3.7) ng/mL, P = 0.012) women. Cord-suPAR was comparable across the groups (median 2.98 (IQR 2.38-3.77) ng/mL). In actively infected women, maternal-suPAR and gestational age were the only independent predictors of birth weight in multivariate linear regression adjusted for maternal-suPAR, HIV-1 infection, age, BMI, haemoglobin, peripheral parasitaemia, parity and gestational age; 1 ng/mL higher maternal-suPAR predicted -56 g (95% CI -100 to -12, P = 0.016) reduced birth weight. Cord-suPAR could not predict birth weight after adjusting for gestational age. Future studies are warranted to investigate whether the maternal suPAR level is increased earlier in pregnancy in women with active placental malaria infection and whether early maternal suPAR measurements can predict birth weight. If so, measurements of maternal suPAR early in pregnancy might then potentially identify women with increased needs for antenatal care and intervention.

The effect of Plasmodium falciparum infection on expression of monocyte surface molecules

Plasmodium falciparum infection may result in severe malaria in susceptible individuals. The pathogenesis of severe disease is probably a combination of the sequestration of infected erythrocytes and overstimulation of the immune response. Monocytes are a key source of many of the pro-inflammatory agents implicated but also are found sequestered in blood vessels. However, little is known about the monocyte phenotype in malaria disease. Flow cytometry was performed on fresh whole blood to determine surface expression of four receptors during acute severe and non-severe malaria and again during convalescence when uninfected. Three hundred and fifty-six children with P. falciparum infection were studied and were found to show increased expression of intercellular adhesion molecule-1 (ICAM-1), urokinase plasminogen activator receptor (uPAR), CD23 and chemokine receptor 5 (CCR5) (P<0.001) during acute disease compared with convalescent levels. Using multivariate analysis, it was found that large increases in expression of ICAM-1 (odds ratio (OR) 2.44, 95% CI 1.80-3.32) and uPAR (OR 3.14, 95% CI 1.93-5.09) but small increases in expression of CD23 (OR 0.82, 95% CI 0.68-0.96) were independently associated with severe malaria. These results give an insight into the cellular processes occurring in severe malaria and suggest that pathology is based on a complex repertoire of pro- and anti-inflammatory processes.

TRPV1 receptors in the CNS play a key role in broad-spectrum analgesia of TRPV1 antagonists

Vanilloid receptor type 1 (TRPV1) is a ligand-gated nonselective cation channel that is considered to be an important integrator of various pain stimuli such as endogenous lipids, capsaicin, heat, and low pH. In addition to expression in primary afferents, TRPV1 is also expressed in the CNS. To test the hypothesis that the CNS plays a differential role in the effect of TRPV1 antagonists in various types of pain, the analgesic effects of two TRPV1 antagonists with similar in vitro potency but different CNS penetration were compared in vivo. Oral administration of either A-784168 (1-[3-(trifluoromethyl)pyridin-2-yl]-N-[4-(trifluoromethylsulfonyl)phenyl]-1,2,3,6-tetrahydropyridine-4-carboxamide) (good CNS penetration) or A-795614 (N-1H-indazol-4-yl-N'-[(1R)-5-piperidin-1-yl-2,3-dihydro-1H-inden-1-yl]urea) (poor CNS penetration) blocked capsaicin-induced acute pain with the same potency. In complete Freund's adjuvant (CFA)-induced chronic inflammatory pain, oral administration of either compound blocked thermal hyperalgesia with similar potency. Furthermore, intraplantar or intrathecal administration of A-784168 blocked CFA-induced thermal hyperalgesia, suggesting that both peripheral and CNS TRPV1 receptors may play a role in inflammatory thermal hyperalgesia. The effects of the two TRPV1 antagonists were further assessed in models presumably mediated by central sensitization, including CFA- and capsaicin-induced mechanical allodynia and osteoarthritic pain. In these models, the potency of the two compounds was similar after intrathecal administration. However, when administered orally, A-784168, with good CNS penetration, was much more potent than A-795614. Together, these results demonstrate that TRPV1 receptors in the CNS play an important role in pain mediated by central sensitization. In addition, these results demonstrate that significant CNS penetration is necessary for a TRPV1 antagonist to produce broad-spectrum analgesia.

Estimation of the sequestered parasite load in severe malaria patients using both host and parasite markers

The virulence of the malaria parasite Plasmodium falciparum is due, in part, to its ability to cytoadhere in deep vascular beds. Our inability to quantify the load of sequestered parasites hampers our understanding of the pathophysiological mechanisms involved in disease progression and complicates diagnosis. In this study we evaluate potential biochemical markers of sequestered load by comparing them with estimates of the sequestered load from a statistical model fitted to longitudinal patterns of peripheral parasite densities in a series of 22 patients with severe Plasmodium falciparum malaria. The markers comprised the host factors: haematocrit, circulating host DNA, sTNF-R75 and parasite derived products HRP2, pLDH, pigments and circulating parasite DNA. We investigated the suitability of these markers in determining sequestered loads in patients on quinine treatment. Observed peripheral parasitaemia, plasma levels of sTNF-R75 and circulating parasite DNA were most strongly correlated with estimates of sequestered loads on admission. However the dynamics of both sTNF-R75 and circulating parasite DNA during follow-up were very different from those of the estimated sequestered mass. These analyses suggest that none of the markers gave reliable estimates of the current sequestered load, though they may reflect the history of infection. Longitudinal analyses are needed that allow for the clearance rates of the marker molecules and for variations between hosts in the history of parasitaemia.

Immune effector mechanisms in malaria

That humans in endemic areas become immune to malaria offers encouragement to the idea of developing protective vaccines. However natural immunity is relatively inefficient, being bought at the cost of substantial childhood mortality, and current vaccines are only partially protective. Understanding potential targets and mechanisms of protective immunity is important in the development and evaluation of future vaccines. Some of the problems in identifying such targets and mechanisms in humans naturally exposed to malaria may stem from conceptual and methodological issues related to defining who in a population is susceptible, problems in defining immune responsiveness at single time points and issues related to antigenic polymorphism, as well as the failure of many current approaches to examine functional aspects of the immune response. Protective immune responses may be directed to the pre erythrocytic parasite, to the free merozoite of the blood stage parasite or to new antigens induced on the infected red cell surface. Tackling the methodological issues of defining protection and immune response, together with studies that combine functional assays with new approaches such as allelic exchange and gene knock out offer opportunities for better defining key targets and mechanisms.

Regulation of immune response by Plasmodium-infected red blood cells

During the asexual blood stage infection of the human malaria parasite, Plasmodium falciparum, parasite-derived proteins are inserted onto the surface of the host red blood cell membrane. These proteins are highly variable and were originally thought only to mediate antigenic variation, and sequestration of parasites from peripheral circulation, thus enabling immune evasion. Recent studies have revealed that PfEMP-1 and other molecules on the P. falciparum-infected red blood cell (PfRBC) activate and modulate the immune response. In this review, we discuss how PfRBCs interact with antigen-presenting cells (APCs) and other cells of the immune system, and how such interactions could modulate the host response to Plasmodium infections.