Sensitivity to food additives, vaso-active amines and salicylates: a review of the evidence

Although there is considerable literature pertaining to IgE and non IgE-mediated food allergy, there is a paucity of information on non-immune mediated reactions to foods, other than metabolic disorders such as lactose intolerance. Food additives and naturally occurring 'food chemicals' have long been reported as having the potential to provoke symptoms in those who are more sensitive to their effects. Diets low in 'food chemicals' gained prominence in the 1970s and 1980s, and their popularity remains, although the evidence of their efficacy is very limited. This review focuses on the available evidence for the role and likely adverse effects of both added and natural 'food chemicals' including benzoate, sulphite, monosodium glutamate, vaso-active or biogenic amines and salicylate. Studies assessing the efficacy of the restriction of these substances in the diet have mainly been undertaken in adults, but the paper will also touch on the use of such diets in children. The difficulty of reviewing the available evidence is that few of the studies have been controlled and, for many, considerable time has elapsed since their publication. Meanwhile dietary patterns and habits have changed hugely in the interim, so the conclusions may not be relevant for our current dietary norms. The conclusion of the review is that there may be some benefit in the removal of an additive or a group of foods high in natural food chemicals from the diet for a limited period for certain individuals, providing the diagnostic pathway is followed and the foods are reintroduced back into the diet to assess for the efficacy of removal. However diets involving the removal of multiple additives and food chemicals have the very great potential to lead to nutritional deficiency especially in the paediatric population. Any dietary intervention, whether for the purposes of diagnosis or management of food allergy or food intolerance, should be adapted to the individual's dietary habits and a suitably trained dietitian should ensure nutritional needs are met. Ultimately a healthy diet should be the aim for all patients presenting in the allergy clinic.

The digital library in the re-inscription of African cultural heritage

African digital libraries have evolved beyond the ‘preservation or access’ debate of the 1990s, and the concomitant compulsion to (un-)systematically convert cultural heritage collections from analogue to digital formats. The challenge now lies in the agility to respond to user needs, to match the selection for digitisation with a more strategic approach towards research relevance and potential research outputs. This paper will examine the symbiotic relationship between preservation, cultural heritage and scholarship in a case study on the description and documentation of extinct African languages. It proposes that the new point of focus lies in digital scholarship, enabling both technical innovation and more intellectual engagement in revisiting the digital library to review, correct and augment transitory records through a new scholarly interpretation of African cultural heritage.

Mapping HIV prevalence using population and antenatal sentinel-based HIV surveys: a multi-stage approach

BACKGROUND

Sound public health policy on HIV/AIDS depends on accurate prevalence and incidence statistics for the epidemic at both local and national levels. However, HIV statistics derived from epidemiological extrapolation models and data sources have a number of limitations that may lead to under- or overestimation of the epidemic. Thus, adjustment techniques need to be employed to correctly estimate the size of the HIV burden.

METHODS

A multi-stage methodological approach is proposed to obtain HIV statistics at subnational levels by combining nationally population-based and antenatal clinic HIV data. The stages range from computing inverse probability weighting (IPW) for consenting to HIV testing, to HIV status prediction modelling, to the recently developed Bayesian multivariate spatial models to jointly model and map multiple HIV risks. The 2010 Malawi Demographic and Health Survey (MDHS 2010) and the 2010 Malawi Antenatal Clinic (ANC 2010) Sentinel HIV data were used for analyses. Gender, residence, employment, marital status, ethnicity, condom use, and multiple sex partners were considered when estimating HIV prevalence.

RESULTS

The observed MDHS 2010 HIV prevalence among people aged 15-49 years was 10.15 %, with 95 % confidence interval (CI) of (9.66, 10.67 %). The ANC 2010 site HIV prevalence had a median of 10.63 %, with 95 % CI ranging from 1.85-24.09 %. The MDHS 2010 prevalence was 10.61 % (9.9, 11.33 %) and 10.19 % (9.69, 10.71 %) using the HIV weight and IPW, respectively. After predicting the HIV status for the non-tested subjects, the overall MDHS 2010 HIV prevalence was 11.05 % (10.80, 11.30 %). Higher HIV prevalence rates were observed in the mostly Southern districts, where poverty and population density levels are also comparatively high. The excess risk attributable to ANC HIV was much larger in the central-eastern and northern parts of the country.

CONCLUSIONS

Inverse Probability Weighting combined with an appropriate HIV prediction model can be a useful tool to correct for non-response to HIV testing, especially if the number of tested individuals is very minimal at subnational levels. In populations where most know their HIV status, population-based HIV prevalence estimates can be heavily biased. High-coverage antenatal clinics' surveillance HIV data would then be the only important HIV data information sources.

Bayesian semiparametric analysis of recurrent failure time data using copulas

The analysis of recurrent event data is of particular importance in medical statistics where patients suffering from chronic diseases often present with multiple recurring relapses or cancer patients experience several tumor recurrences. Whereas individual subjects can be assumed to be independent, the times between events of one subject are neither independent nor identically distributed. Apart from the marginal approach by Wei et al. (1989), the shared frailty model, see for example Duchateau and Janssen (2008), has been used extensively to analyze recurrent event data, where the correlation between sequential times is implicitly taken into account via a random effect. Oakes (1989) and Romeo et al. (2006) showed and exemplified the equivalence of frailty models for bivariate survival data to Archimedean copulas. Despite the fact that copula-based models have been used to model parallel survival data, their application to recurrent failure time data has only recently been suggested by Lawless and Yilmaz (2011) for the bivariate case. Here, we extend this to more than two recurrent events and model the joint distribution of recurrent events explicitly using parametric copulas within a Bayesian framework. This framework allows for parametric as well as a nonparametric modeling of the marginal baseline hazards and models the influence of covariates on the marginals via a proportional hazards assumption. Furthermore, the parameters of the copula may also depend on the covariates. We illustrate the flexibility of this approach using data from an asthma prevention trial in young children.

Influence of gelsolin deficiency on excitation contraction coupling in adult murine cardiomyocytes

Ion channels involved in cardiac excitation-contraction coupling are linked to the cytoskeleton. Therefore changes in the cytoskeletal actin filaments may influence cardiac membrane currents and electro-mechanical coupling. Depolymerization of actin filaments by gelsolin (gsn) is involved in the organisation of the cytoskeleton by leading to a lower polymerization state. Gsn is activated by Ca(2+) and inhibited by phosphoinositol-bisphosphate (PIP2). Furthermore, gsn has been linked to pathological conditions with reduced contractility like heart failure, amyloidosis and apoptosis. Thus, we hypothesize, that gsn deficiency may change electromechanical properties of freshly isolated ventricular cardiomyocytes. We recorded L-type Ca(2+) current (ICa,L) in whole-cell patch clamp mode in freshly isolated ventricular cardiomyocytes from gsn deficient ((-/-)) and control (gsn(+/+)) mice. Sarcomere shortening was monitored in field-stimulated myocytes from 0.5 Hz to 10 Hz by video microscopy. Shortening-frequency relation, post-rest potentiation and β-adrenergic stimulation were investigated. ICa,L was increased in gsn(-/-) vs. gsn(+/+) myocytes. Sarcomere shortening amplitude and velocity were enhanced in gsn(-/-) vs. gsn(+/+) at all frequencies. Shortening-frequency relationship showed a biphasic pattern with decay in shortening amplitude between 0.5 and 2 Hz and an increase at higher frequencies in both genotypes. Post-rest characteristics revealed a frequency-dependent decay of post-rest potentiation in gsn(+/+) while it remained stable in gsn(-/-). In gsn(-/-) a reduced response to β-adrenergic stimulation was observed. Resting sarcomere length was shorter in gsn(-/-) but neither increasing frequency nor β-adrenergic stimulation induced further decay in any of the genotypes. In summary, gsn deficiency had a profound effect on excitiation-contraction properties and improved systolic function while not affecting diastolic function in unloaded isolated cardiomyocytes. Therefore, gsn mediated effects on contractility may play a role in patients with heart failure and cancer, where gsn levels are known to be elevated.

The effect of 2 mMol glutamine supplementation on HSP70 and TNF-α release by LPS stimulated blood from healthy children

OBJECTIVE

Glutamine has been shown to promote heat shock protein 70 (HSP70) release both within experimental in vitro models of sepsis (2-10 mM) and in adults post trauma (0.5 g/kg), although the efficacy varies and is dependent on the model used. The effect of glutamine supplementation on HSP70 release in children is less clear. Therefore, the aim of this study was to investigate the effect of 2 mM glutamine added to incubation media on HSP70 and inflammatory mediator release in an in vitro model of paediatric sepsis using whole blood from healthy paediatric volunteers.

METHODS

An in vitro whole blood endotoxin stimulation model using 1 μg/ml lipopolysaccharide (LPS) over a 24 h time period was used to investigate the effects of 2 mM glutamine on HSP70 and inflammatory mediator release in healthy children.

RESULTS

The addition of 2 mM glutamine to the incubation media significantly increased HSP70 release over time (p < 0.05). This was associated with an early pro-inflammatory effect on TNF-α release at 4 h (p < 0.005) which was not seen at 24 h. There was a non significant trend towards higher levels of IL-6 and IL-10 following the addition of 2 mM glutamine, which appears to differ from the response reported in adult and animal models.

CONCLUSION

Glutamine supplementation of incubation media promotes HSP70 and early TNF- α release in an in vitro model using blood samples from healthy children.

Consensus on performing skin biopsies, laboratory workup, evaluation of tissue samples and reporting of the results in patients with suspected cutaneous graft-versus-host disease

BACKGROUND

Histopathological diagnosis including selection of lesions, the determination of the best point of time for biopsy and workup is not trivial in cutaneous graft-versus-host disease (GvHD).

OBJECTIVES

To develop interdisciplinary recommendations on performing, the laboratory work up and reporting of the results of skin biopsies in patients with suspected cutaneous GvHD.

METHODS

A working group consisting of dermatopathologists, dermatologists, transplant-physicians and transplant-pathologists prepared recommendations for performing skin biopsies, laboratory workup and evaluation of tissue samples, and reporting of the results in patients with cutaneous GvHD. After achieving a consensus within the working group, a survey that comprised the core issues of the recommendations was electronically sent out to 72 alloHSCT centres within Germany, Austria, and Switzerland and their Departments of Pathology. The answers were discussed in a Consensus Conference and final recommendations were established.

RESULTS

Twenty-five centres responded to the clinical and 17 centres to the histopathological survey. Questions addressed to the clinicians comprised the indication for skin biopsy in chronic GvHD (cGvHD) and acute GvHD (aGvHD) and the appropriate point of time for skin biopsy. Eighty-eight per cent agreed that the skin biopsy is generally indicated in patients with suspected cGvHD lacking diagnostic features. In contrast, with suspected aGvHD, only 62% of respondents felt that skin biopsy was necessary even if GvHD had not been confirmed in another organ. Although restricted due to the fact that immunosuppression is often applied in an emergency setting most centres supported skin biopsies before initiation of topical or systemic immunosuppression. The majority of pathologists agreed that in non-sclerotic GvHD a punch biopsy is adequate, whereas in sclerotic GvHD a scalpel biopsy is preferred.

CONCLUSION

While a consensus on the need for biopsies in cGvHD was reached the value of skin biopsies in aGvHD and subsequent biopsies during therapy requires further evaluation.

Plasmonically enhanced electron escape from gold nanoparticles and their polarization-dependent excitation transfer along DNA nanowires

Here we show plasmon mediated excitation transfer along DNA nanowires over up to one micrometer. Apparently, an electron excitation is initiated by a femtosecond laser pulse that illuminates gold nanoparticles (AuNP) on double stranded DNA (dsDNA). The dependency of this excitation on laser wavelength and polarization are investigated. Excitation of the plasmon resonance of the AuNPs via one- and two-photon absorption at 520 and 1030 nm, respectively, was explored. We demonstrate an excitation transfer along dsDNA molecules at plasmon supported four-photon excitation of AuNP cluster or at laser field driven nanoparticle electron tunneling for an alignment of the attached dsDNA to the polarization of the electric field of the laser light. These results extend the previously observed plasmonically induced three-photon excitation transfer along DNA nanowires to another nanoparticle material (gold) and the adapted irradiation wavelengths.

EAACI Food Allergy and Anaphylaxis Guidelines. Food allergy health-related quality of life measures

Instruments have been developed and validated for the measurement of health-related quality of life in patients with food allergy. This guideline has been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Guidelines for Food Allergy and Anaphylaxis Group. It draws on a systematic review of the literature on quality of life instruments for food allergy and the Appraisal of Guidelines for Research & Evaluation (AGREE II) guideline development process. Guidance is provided on the use of such instruments in research, and the current limitations of their use in clinical practice are described. Gaps in current knowledge as well as areas of future interest are also discussed. This document is relevant to healthcare workers dealing with food-allergic patients, scientists engaging in food allergy research and policy makers involved in regulatory aspects concerning food allergy and safety.

Comparison of intensity-dependent inhibition of spinal wide-dynamic range neurons by dorsal column and peripheral nerve stimulation in a rat model of neuropathic pain

BACKGROUND

Spinal cord stimulation (SCS) and peripheral nerve stimulation (PNS) are thought to reduce pain by activating a sufficient number of large myelinated (Aβ) fibres, which in turn initiate spinal segmental mechanisms of analgesia. However, the volume of neuronal activity and how this activity is associated with different treatment targets is unclear under neuropathic pain conditions.

METHODS

We sought to delineate the intensity-dependent mechanisms of SCS and PNS analgesia by in vivo extracellular recordings from spinal wide-dynamic range neurons in nerve-injured rats. To mimic therapeutic SCS and PNS, we used bipolar needle electrodes and platinum hook electrodes to stimulate the dorsal column and the tibial nerve, respectively. Compound action potentials were recorded to calibrate the amplitude of conditioning stimulation required to activate A-fibres and thus titrate the volume of activation.

RESULTS

Dorsal column stimulation (50 Hz, five intensities) inhibited the windup (a short form of neuronal sensitization) and the C-component response of wide-dynamic range neurons to graded intracutaneous electrical stimuli in an intensity-dependent manner. Tibial nerve stimulation (50 Hz, three intensities) also suppressed the windup in an intensity-dependent fashion but did not affect the acute C-component response.

CONCLUSIONS

SCS and PNS may offer similar inhibition of short-term neuronal sensitization. However, only SCS attenuates spinal transmission of acute noxious inputs under neuropathic pain conditions. Our findings begin to differentiate peripheral from spinal-targeted neuromodulation therapies and may help to select the best stimulation target and optimum therapeutic intensity for pain treatment.

Efficient parallelization of short-range molecular dynamics simulations on many-core systems

This article introduces a highly parallel algorithm for molecular dynamics simulations with short-range forces on single node multi- and many-core systems. The algorithm is designed to achieve high parallel speedups for strongly inhomogeneous systems like nanodevices or nanostructured materials. In the proposed scheme the calculation of the forces and the generation of neighbor lists are divided into small tasks. The tasks are then executed by a thread pool according to a dependent task schedule. This schedule is constructed in such a way that a particle is never accessed by two threads at the same time. Benchmark simulations on a typical 12-core machine show that the described algorithm achieves excellent parallel efficiencies above 80% for different kinds of systems and all numbers of cores. For inhomogeneous systems the speedups are strongly superior to those obtained with spatial decomposition. Further benchmarks were performed on an Intel Xeon Phi coprocessor. These simulations demonstrate that the algorithm scales well to large numbers of cores.