How does dose impact on the severity of food-induced allergic reactions, and can this improve risk assessment for allergenic foods?: Report from an ILSI Europe Food Allergy Task Force Expert Group and Workshop.

Quantitative risk assessment (QRA) for food allergens has made considerable progress in recent years, yet acceptability of its outcomes remains stymied because of the limited extent to which it has been possible to incorporate severity as a variable. Reaction severity, particularly following accidental exposure, depends on multiple factors, related to the allergen, the host and any treatments, which might be administered. Some of these factors are plausibly still unknown. Quantitative risk assessment shows that limiting exposure through control of dose reduces the rates of reactions in allergic populations, but its impact on the relative frequency of severe reactions at different doses is unclear. Food challenge studies suggest that the relationship between dose of allergenic food and reaction severity is complex even under relatively controlled conditions. Because of these complexities, epidemiological studies provide very limited insight into this aspect of the dose-response relationship. Emerging data from single-dose challenges suggest that graded food challenges may overestimate the rate of severe reactions. It may be necessary to generate new data (such as those from single-dose challenges) to reliably identify the effect of dose on severity for use in QRA. Success will reduce uncertainty in the susceptible population and improve consumer choice.

Multi-mode absorption spectroscopy using a quantum cascade laser for simultaneous detection of NO and H2O.

Detection of multiple transitions in NO and H2O using multi-mode absorption spectroscopy, MUMAS, with a quantum cascade laser, QCL, operating at 5.3 µm at scan rates up to 10 kHz is reported. The linewidth of longitudinal modes of the QCL is derived from pressure-dependent fits to experimental MUMAS data. Variations in the spectral structure of the broadband, multi-mode, output of the commercially available QCL employed are analysed to provide accurate fits of modelled MUMAS signatures to the experimental data.

Multi-species sensing using multi-mode absorption spectroscopy with mid-infrared interband cascade lasers.

The application of an interband cascade laser, ICL, to multi-mode absorption spectroscopy, MUMAS, in the mid-infrared region is reported. Measurements of individual mode linewidths of the ICL, derived from the pressure dependence of lineshapes in MUMAS signatures of single, isolated, lines in the spectrum of HCl, were found to be in the range 10-80 MHz. Multi-line spectra of methane were recorded using spectrally limited bandwidths, of approximate width 27 cm-1, defined by an interference filter, and consist of approximately 80 modes at spectral locations spanning the 100 cm-1 bandwidth of the ICL output. Calibration of the methane pressures derived from MUMAS data using a capacitance manometer provided measurements with an uncertainty of 1.1 %. Multi-species sensing is demonstrated by the simultaneous detection of methane, acetylene and formaldehyde in a gas mixture. Individual partial pressures of the three gases are derived from best fits of model MUMAS signatures to the data with an experimental error of 10 %. Using an ICL, with an inter-mode interval of ~10 GHz, MUMAS spectra were recorded at pressures in the range 1-10 mbar, and, based on the data, a potential minimum detection limit of the order of 100 ppmv is estimated for MUMAS at atmospheric pressure using an inter-mode interval of 80 GHz.

Mid-infrared multi-mode absorption spectroscopy using interband cascade lasers for multi-species sensing.

An interband cascade laser (ICL) operating at 3.7 µm has been used to perform multimode absorption spectroscopy, MUMAS, at scan rates up to 10 kHz. Line widths of individual modes in the range 10-80 MHz were derived from isolated lines in the MUMAS signatures of HCl. MUMAS data for methane covering a spectral range of 30 nm yielded a detection level of 30 µbar·m for 1 s measurement time at 100 Hz. Simultaneous detection of methane, acetylene, and formaldehyde in a gas mixture containing all three species is reported.

High-precision measurement of the 19Ne half-life and implications for right-handed weak currents.

We report a precise determination of the (19)Ne half-life to be T(1/2)=17.262±0.007 s. This result disagrees with the most recent precision measurements and is important for placing bounds on predicted right-handed interactions that are absent in the current standard model. We are able to identify and disentangle two competing systematic effects that influence the accuracy of such measurements. Our findings prompt a reassessment of results from previous high-precision lifetime measurements that used similar equipment and methods.

A 90-day subchronic toxicity study and reproductive toxicity studies on ACE-inhibiting lactotripeptide.

In recent years there has been an increasing body of literature describing the antihypertensive effects of peptides produced from milk protein. The tripeptides isoleucine-proline-proline (IPP) and valine-proline-proline (VPP), isolated from hydrolysed casein have been shown to lower blood pressure by inhibiting angiotensin I-converting enzyme (ACE). This has led to the use of these tripeptides, collectively referred to as lactotripeptide (LTP) as ingredients of functional foods intended to help control blood pressure. A programme of studies including a 90-day repeat-dose oral gavage toxicity study in the rat and an embryo-fetal (pre-natal) development study in the rabbit was conducted to ensure the safety of this ACE-inhibiting ingredient. In addition, a non-standard pre- and post-natal development study in the rat was performed. This study included direct dosing of the neonates, and was designed specifically to investigate renal development and to ensure that the bioactive peptides were not associated with the same type of fetopathy exhibited by ACE inhibiting drugs. These studies showed that there were no adverse effects of treatment at the highest doses tested.

Rothia dentocariosa endophthalmitis following intravitreal injection-a case report.

PURPOSE: This report describes the first recognised case of Rothia dentocariosa endophthalmitis following intravitreal injection. CASE REPORT: A 57-year-old indigenous Australian diabetic female developed pain, redness and decreased vision 3 days after intravitreal aflibercept injection to the right eye-administered for diabetic vitreous haemorrhage with suspected macular oedema and proliferative diabetic retinopathy. Examination revealed best corrected visual acuity (BCVA) of hand movements, ocular hypertension and marked anterior chamber inflammation. The left eye was unaffected but had a BCVA of 6/24 due to pre-existing diabetic retinopathy. Vitreous culture isolated Rothia dentocariosa as the organism responsible for the endophthalmitis. The following treatment with intraocular cephazolin, vancomycin and ceftazidime, topical ciprofloxacin and gentamicin and systemic ciprofloxacin, the patient underwent vitrectomy. Nine weeks after onset, the patient's BCVA had improved to 6/36, and fundal examination revealed extensive retinal necrosis. CONCLUSION: Rothia dentocariosa is presented as a rare cause of endophthalmitis following intravitreal injection and reports the appearance of 'pink hypopyon' previously observed with other organisms. Its identification also demonstrates the risk of oral bacterial contamination during intraocular injections. Vigilance with strategies to minimise bacterial contamination in the peri-injection period are important. Further research to identify additional techniques to prevent contamination with oral bacteria would be beneficial, including whether a role exists for patients wearing surgical masks during intravitreal injections.

Stability in metabolic phenotypes and inferred metagenome profiles before the onset of colitis-induced inflammation.

Inflammatory bowel disease (IBD) is associated with altered microbiota composition and metabolism, but it is unclear whether these changes precede inflammation or are the result of it since current studies have mainly focused on changes after the onset of disease. We previously showed differences in mucus gut microbiota composition preceded colitis-induced inflammation and stool microbial differences only became apparent at colitis onset. In the present study, we aimed to investigate whether microbial dysbiosis was associated with differences in both predicted microbial gene content and endogenous metabolite profiles. We examined the functional potential of mucus and stool microbial communities in the mdr1a -/- mouse model of colitis and littermate controls using PICRUSt on 16S rRNA sequencing data. Our findings indicate that despite changes in microbial composition, microbial functional pathways were stable before and during the development of mucosal inflammation. LC-MS-based metabolic phenotyping (metabotyping) in urine samples confirmed that metabolite profiles in mdr1a -/- mice were remarkably unaffected by development of intestinal inflammation and there were no differences in previously published metabolic markers of IBD. Metabolic profiles did, however, discriminate the colitis-prone mdr1a -/- genotype from controls. Our results indicate resilience of the metabolic network irrespective of inflammation. Importantly as metabolites differentiated genotype, genotype-differentiating metabolites could potentially predict IBD risk.

The measurement of salivary cadmium by electrothermal atomic absorption spectrophotometry and its use as a biological indicator of occupational exposure.

We have examined the potential use of salivary cadmium measurements for the biological monitoring of occupational cadmium exposure, paying particular attention to the contamination risks associated with such measurements. We have developed a method for the direct determination of cadmium in saliva by graphite furnace atomic absorption spectrophotometry, which minimizes the risk of contamination during sample preparation and analysis. The limit of detection is 0.6 nmoll-1, which is sufficiently sensitive to discriminate between unexposed and occupationally exposed individuals. The method has been employed to measure cadmium levels in saliva samples collected by two different methods from an unexposed population, a group of ex-workers previously exposed to cadmium (Group 1), and two groups of currently exposed workers (Groups 2 and 3). Salivary cadmium levels were significantly raised in both of the groups of currently exposed individuals (group 2 median (Md) = 17 nmoll-1, group 3 Md = 70 nmoll-1, p greater than 0.0001), and in past workers with previous long-term exposure (Group 1 Md = 2.5 nmoll-1, p greater than 0.001) when compared with an unexposed population. The results suggest that the measurement of salivary cadmium may reflect recent exposure to the metal. However, considerable care must be taken in collecting samples because a risk of contamination during sampling is apparent with procedures commonly used for saliva collection, and for this reason the applicability of such measurements for biological monitoring is limited.

A subchronic 90-day oral rat toxicity study and in vitro genotoxicity studies with a conjugated linoleic acid product.

Conjugated linoleic acid (CLA) is the term given to a group of positional and geometric isomers of the essential fatty acid linoleic acid. CLA is found naturally in foods such as dairy and meat products. CLA is reported to have a number of beneficial effects including anticarcinogenic activity. However, safety data are limited. Clarinol G80 is a commercial preparation containing equal amounts of the 9cis,11trans and 10trans,12cis CLA isomers in the form of glycerides. In order to support the safety-in-use of Clarinol G80 as an ingredient in food, the preparation was tested in two in vitro mutagenicity assays, an Ames test and an in vitro cytogenetics assay, and a 90-day repeat-dose oral toxicity rat study. Clarinol G80 was non-mutagenic in both in vitro assays. In the 90-day study, Clarinol G80 produced hepatocellular hypertrophy in female rats at the highest dose level (15% w/w). This effect was an adaptive effect in response to feeding high levels of Clarinol G80 in the diet and was reversible upon withdrawal of test material. An increase in plasma insulin levels was also observed female rats fed 15% w/w Clarinol G80 but there was no effect on plasma glucose levels. A No Observed Adverse Effect Level of 2433 mg/kg bw/day for male and 2728 mg/kg bw/day female rats was identified in the study.

Organochlorine pesticide residues in human milk in the United Kingdom 1997 - 8.

1 The concentrations of a range of organochlorine pesticide residues have been determined in 168 samples of human milk collected between January 1997 and May 1998 in the UK. 2 Of the 18 residues sought, only p,p'-DTT, p,p'-DDE, dieldrin, HCB, beta-HCH and gamma-HCH were detected. 3 The continuing trend of a reduction in the concentrations of these pesticide residues in human milk samples and in the percentage of human milk samples containing residues was seen. 4 Correlations between the concentrations of p,p'-DDE, dieldrin, HCB, beta-HCH and gamma-HCH and age were seen. 5 When compared to studies carried out in Europe over a similar time period, residues in this present study were shown to occur at similar or lower concentrations.

A multi-criteria decision analysis model to assess the safety of botanicals utilizing data on history of use.

Botanicals (herbal materials and extracts) are widely used in traditional medicines throughout the world. Many have an extensive history of safe use over several hundreds of years. There is now a growing consumer interest in food and cosmetic products, which contain botanicals. There are many publications describing the safety assessment approaches for botanicals, based on the history of safe use. However, they do not define what constitutes a history of safe use, a decision that is ultimately a subjective one. The multi-criteria decision analysis (MCDA), is a model that has been developed, which assesses the safety of botanical ingredients using a history of use approach. The model evaluates the similarity of the botanical ingredient of interest to its historic counterpart - the comparator, the evidence supporting the history of use, and any evidence of concern. The assessment made is whether a botanical ingredient is as safe as its comparator botanical, which has a history of use. In order to establish compositional similarity between the botanical ingredient and its comparator, an analytical 'similarity scoring' approach has been developed. Applicability of the model is discussed with an example, Brahmi ( Bacopa monnieri).This evolution of the risk assessment of botanicals gives an objective, transparent, and transferable safety assessment approach.

Aeromonas sobria endophthalmitis.

BACKGROUND: Aeromonas sobria causes a rare Gram-negative bacterial water-borne infection. It has been found in waters of North Queensland and South-east Asia. Of all Aeromonas species, A. sobria is the most virulent and invasive and has been reported to cause soft tissue infection and corneal ulcer. METHODS: A 14-year-old Caucasian male from North Queensland presented following a penetrating eye injury in which a water bird (cormorant species) had pecked his eye while he was fishing. A fulminant endophthalmitis developed despite treatment with intravenous, intravitreal and topical antibiotics and initial wound repair. Enucleation was performed. RESULTS: Aeromonas sobria was isolated from the vitreous aspirate. CONCLUSION: Aeromonas sobria infection should be suspected in water-contaminated penetrating eye injuries. The prognosis in this case was poor.

A comparison of the haemagglutinating and enzymic activities of Bacteroides fragilis whole cells and outer membrane vesicles.

The haemagglutinating and enzymic activities of the obligately anaerobic pathogenic bacterium Bacteroides fragilis were examined. Outer membrane vesicles are released from the surface of B. fragilis. They can be detected by electron microscopy in ultrathin sections and bacterial suspensions after negative staining. Electron microscopy and immunogold labelling with a MAb specific for surface polysaccharide of B. fragilis confirmed that the vesicles carried outer membrane associated epitopes. The haemagglutinating activity of whole cells from populations of B. fragilis strains NCTC9343, BE3 and LS66 enriched by Percoll density gradient centrifugation for a large capsule (LC), electron dense layer (EDL); non-capsulate by light microscopy) and outer membrane vesicles (OMV) which had been purified by centrifugation from EDL-enriched populations were compared using human and horse erythrocytes. The enzymic activity of OMV, LC- and EDL-enriched populations, as detected by the API ZYM kit, was compared for strains NCTC 9343 and BE3. Purified OMV from the strains examined exhibited both haemagglutinating and enzymatic activity. Haemagglutination by the EDL-enriched population was sensitive to treatment with sodium periodate. The LC-enriched population haemagglutinated only after ultrasonic removal of the capsule. This indicates that the LC masks a haemagglutinin. The results suggest a potential role for OMV in the virulence of B. fragilis.

Hypothyroidism in textile workers.

Four cases of overt hypothyroidism, three of whom were men in their early forties, had occurred over a period of 6 years at a textile factory where thiourea and resorcinol were used in the finishing departments. A follow-up survey of 189 men and 48 women (44 per cent of employees) revealed 12 new cases of varying grades of hypothyroidism, categorized after the system proposed by Evered. These included a case of mild hypothyroidism in a male worker, who subsequently received thyroid hormone replacement therapy as a hospital out-patient. A full occupational hygiene survey was carried out to determine possible sources of exposure to thiourea and resorcinol. Although we were unable to demonstrate a statistically significant occurrence of biochemically and immunologically detectable disturbances in thyroid function among this workforce, we did note that three of the original index cases and several of those workers with varying degrees of minor dysfunction in the follow-up study seemed to cluster in locations where exhausted fumes could accumulate.

Thrombin, unlike vasopressin, appears to stimulate two distinct guanine nucleotide regulatory proteins in human platelets.

The thrombin-stimulated GTPase activity of human platelets was additive with respect to the GTPase stimulation effected by prostaglandin E1, but not with that stimulated by adrenaline, vasopressin and platelet-activating factor (PAF). Treatment of platelet membranes with pertussis toxin partially inhibited the thrombin-stimulated GTPase, but had no effect on the vasopressin-stimulated GTPase activity, whereas cholera toxin treatment had no effect on either of these stimulated GTPase activities. Thrombin, adrenaline and PAF, but not vasopressin, inhibited the adenylate cyclase activity of isolated plasma membranes through the action of Ni only, this being inhibited by pertussis toxin. It is suggested that thrombin exerts effects through both the inhibitory guanine nucleotide regulatory protein Ni and through the putative guanine nucleotide regulatory protein, Np, involved in regulating receptor-stimulated inositol phospholipid metabolism. However, vasopressin appears to exert its effects solely through the putative Np.