Lesion of posterior parietal cortex in rats does not disrupt place avoidance based on either distal or proximal orienting cues

A current topic in neurobiology is the study of the role of various brain structures in processing of spatial information. The present study was aimed at elucidating the role of the rat posterior parietal cortex in performing a place avoidance task. Two variants of the task were used: an arena frame task, in which animals were trained to avoid a sector defined by local cues bound to the surface of a rotating arena, and the room frame task, in which the shock sector was defined with respect to distal room landmarks. The results showed that both control and lesioned rats were able to efficiently solve both tasks, while locomotion was not altered. These results suggest that the posterior parietal cortex is not crucial for the processing of either proximal or distal cues in place avoidance.     

The effects of distant and on-line visual information on the control of approach phase and step over an obstacle during locomotion

One of the goals of this study was to examine the nature and role of distant visual information sampled during locomotion in the feedforward control of leading and trailing limb while an individual is required to step over an obstacle in the travel path. In addition we were interested in whether or not on-line visual information available while the limb (lead or trail) is stepping over the obstacle influences limb trajectory control and whether the information provided during lead limb cross would be used to calibrate movement of the trail limb. Towards this end, we manipulated availability of vision following an initial dynamic sampling period during the approach phase in proximity to the obstacle and during the lead and trail limb stepping over the obstacle. Ten participants completed 40 trials of obstacle crossing in 8 testing conditions. Initial dynamic visual sampling was sufficient to ensure successful task performance in the absence of vision in the approach phase and during both lead and trail limb stepping over the obstacle. Despite successful task performance, foot placement of the lead and trail limb before obstacle crossing and limb elevation over the obstacle were increased after withdrawal of vision in the approach area. Furthermore, the correlation between toe clearance and foot placement was diminished. While both limbs require feedforward visual information to control the step over the obstacle, only lead limb elevation was influenced by availability of on-line visual information during obstacle crossing. Results were in agreement with the notion of primacy of information inherent in the optic array over those from static samples of the environment in guiding locomotion. It is suggested that the expected proprioceptive feedback information associated with the limb posture before the obstacle, reconstructed using visual memory from dynamic sampling of the environment, mismatched with those from the actual limb position. Accordingly, participants adopted a different strategy that enabled them to clear the obstacle with a higher safety margin.Financial assistance was provided by a grant from the Office of Naval Research, USA, NSERC/Canada, and CAPES/Brazil. We would like to thank Milad G. Ishac, Mike Greig, Zinat Shafaei-Shirazi, and Candida T. Goncalves for their assistance     

Oral Sodium Cromoglycate Treatment of Atopic Dermatitis Related to Food Allergy

Thirty-two children and two adults with chronic atopic dermatitis related to food allergy entered this double-blind crossover study comparing oral sodium cromoglycate (200–1600 mg/24 h) with placebo. Each treatment period comprised 6 weeks: 1 weeks on elimination diet, and 2 weeks on a normal. i.e. unrestricted diet. The diagnosis of food allergy was made after clinical improvement with elimination diet and relapse after challenge. Overall analysis of skin symptoms evaluated by means of clinical assessments and diary cards, opinions of treatment, and use of concomitant medication gave no evidence of any difference between sodium cromoglycate and placebo. Unusual symptoms were reported by 18 patients. In one case the patient was withdrawn during the sodium cromoglycate period because of side effects. The majority of symptoms with both treatments were stomach problems. Overall analysis of the laboratory data gave no significant differences between treatments.     

Open-field behavior, habituation and passive avoidance learning: Effect of ACTH and hydrocortisone on Normal and adrenalectomized rats

Exploratory behavior (GMA) and habituation rate (IH) were studied in an open-field situation in normal and adrenalectomized rats. Following this procedure the rats were subjected to passive avoidance learning (PA). Wide-spreading individual differences were observed in the exploratory behavior and the tendency of habituation of normal rats. As compared to the normal values, either the adrenalectomy which was performed 24 hr, 7 days and 28 days prior to the experiments or the ACTH and hydrocortisone treatment failed to modify the GMA and the IH significantly. An improvement of PA was found in the normal rats following ACTH and hydrocortisone treatment. In the adrenalectomized animals the hydrocortisone proved to be effective, whereas ACTH did not influence PA. No correlation was found between GMA, IH versus PA values and the influence of ACTH and hydrocortisone administration on these parameters. It is concluded that the direction of PA is unpredictable on the basis of the open-field test performed on R-Amsterdam strain of rats, and the effect of ACTH on passive avoidance learning is mediated through the adrenal glands.     

Combined skin prick and patch testing enhances identification of peanut-allergic patients with atopic dermatitis

BACKGROUND: Food atopy patch tests (APTs) are considered a useful tool for the diagnosis of food allergy. Hypersensitivity to peanuts has not been investigated by means of APTs so far. METHODS: APTs and skin prick tests (SPTs) with peanuts were performed in 136 atopic dermatitis (AD) patients. Relevance of positive and negative responses to these tests was assessed by repeated open challenges with peanuts. RESULTS: Nine percent of our AD patients reacted to the challenge. Positive responses to APTs were recorded in 19% of the patients, whereas in 12% positive SPTs were observed. APTs were more frequently positive in subjects with eczematous responses after challenge with respect to those with urticarial reactions. SPT reactivity proved to be higher in patients above 12 years of age, whereas APT positivity was more frequent in children under 6 years. APT sensitivity proved significantly higher than SPT sensitivity, in particular in children under 12 years of age. On the contrary, SPT specificity and positive predictive value were significantly higher with respect to those of APT in the age group of subjects under 6 years of age. CONCLUSIONS: Our data suggest that APTs with peanuts may represent a useful integration to standard testing modalities employed for the diagnosis of peanut allergy in AD patients.     

Peanut-induced anaphylaxis in children and adolescents: Data from the European Anaphylaxis Registry

Background

Peanut allergy has a rising prevalence in high-income countries, affecting 0.5%–1.4% of children. This study aimed to better understand peanut anaphylaxis in comparison to anaphylaxis to other food triggers in European children and adolescents.

Methods

Data was sourced from the European Anaphylaxis Registry via an online questionnaire, after in-depth review of food-induced anaphylaxis cases in a tertiary paediatric allergy centre.

Results

3514 cases of food anaphylaxis were reported between July 2007 - March 2018, 56% in patients younger than 18 years. Peanut anaphylaxis was recorded in 459 children and adolescents (85% of all peanut anaphylaxis cases). Previous reactions (42% vs. 38%; p = .001), asthma comorbidity (47% vs. 35%; p < .001), relevant cofactors (29% vs. 22%; p = .004) and biphasic reactions (10% vs. 4%; p = .001) were more commonly reported in peanut anaphylaxis. Most cases were labelled as severe anaphylaxis (Ring&Messmer grade III 65% vs. 56% and grade IV 1.1% vs. 0.9%; p = .001). Self-administration of intramuscular adrenaline was low (17% vs. 15%), professional adrenaline administration was higher in non-peanut food anaphylaxis (34% vs. 26%; p = .003). Hospitalization was higher for peanut anaphylaxis (67% vs. 54%; p = .004).

Conclusions

The European Anaphylaxis Registry data confirmed peanut as one of the major causes of severe, potentially life-threatening allergic reactions in European children, with some characteristic features e.g., presence of asthma comorbidity and increased rate of biphasic reactions. Usage of intramuscular adrenaline as first-line treatment is low and needs to be improved. The Registry, designed as the largest database on anaphylaxis, allows continuous assessment of this condition.

     

Lettuce anaphylaxis: identification of a lipid transfer protein as the major allergen

BACKGROUND: Allergy to plant-derived foods is associated with birch pollinosis in central and northern Europe. Symptoms elicited are usually limited to the oropharyngeal system. By contrast, in the Mediterranean area, allergy to the same foods manifests more frequently with systemic reactions caused by nonspecific lipid transfer proteins (nsLTP), independently of an associated pollinosis. OBJECTIVE: We sought to investigate the pattern of immunoglobulin E (IgE) binding protein bands implicated in lettuce allergy, in particular the presence of an nsLTP. METHODS: Consecutive lettuce allergic patients were selected. Determination of serum-specific IgE, immunoblot, and inhibition experiments were performed in order to study the pattern of IgE binding proteins and the potential cross-reactivity to pollens. Inhibition studies with recombinant allergens were conducted to identify the lettuce allergens. The major allergen was subjected to N-terminal amino acid sequencing. RESULTS: Fourteen patients were diagnosed as being allergic to lettuce. All were sensitized to Platanus pollen. Ten of them showed specific IgE to a lettuce protein of 9-kDa. The IgE binding to this protein was completely inhibited by the cherry-LTP and peach extract. The N-terminal sequence of the 9-kDa protein showed a high degree of amino acid sequence identity to other nsLTPs. A clear partial cross-reactivity was observed between lettuce-LTP and Platanus-pollen extract. CONCLUSIONS: An LTP has been demonstrated to be a major allergen in patients suffering from lettuce allergy.     

Cashew allergy: observations of 42 children without associated peanut allergy

BACKGROUND: Cashew allergy seems to be increasingly frequent. The goal of the present study was to analyse the clinical features and results of investigations of 42 children with cashew allergy. METHODS: The clinical features and results of skin prick tests, specific IgE assays, and food challenges were analysed. RESULTS: The mean age at first allergic reaction was 2 years and the mean age at diagnosis of cashew allergy was 2.7 years. One in five children (12%) had a prior history of exposure to cashew nuts. Fifty-six per cent had skin symptoms, 25% had respiratory signs and 17% had digestive signs. Eighteen children had proven, associated food allergies (pistachio, seven; egg, five; mustard, three; shrimp, two; cow milk, one). The mean wheal diameter of the skin prick tests was 7 mm (3-16 mm) and the mean specific IgE level was 3.1 kUA/L (<0.35->100 kUA/L). Eight children had positive food challenges. CONCLUSION: The increase in cashew allergy is worrying because it affects young children who may have a reaction without ever having been exposed to cashews. Almost one-third of children are allergic to pistachios, which belong to the same botanical family as cashews. Clinical history is generally and sufficiently suggestive to diagnose cashew allergy without recourse to food challenges.     

Effects of central amygdaloid nucleus lesions on ingestion, taste reactivity, exploration and taste aversion.

Central amygdaloid nucleus lesions in rats had no effect on recovery of preoperative body weight and food consumption levels. The brain damaged rats also recovered preoperative levels of water consumption as rapidly as control rats but then developed a mild but persistent hypodipsia. The experimental rats also drank less than control rats when food deprived and showed marginally reliable decreases in 0.1% quinine solution consumption and latency to consume a novel food. There was no detectable lesion effect on 0.1% saccharin solution consumption, exploration of a novel environment or formation of a learned taste aversion. It is suggested that the central amygdaloid nucleus has a role in mediating the relationship between food and water intake and in some taste mediated consummatory behavior.     

Ara h 8, a Bet v 1-homologous allergen from peanut, is a major allergen in patients with combined birch pollen and peanut allergy

BACKGROUND: We recently described patients with soybean allergy mainly mediated by cross-reactivity to birch pollen allergens. A majority of those patients were reported to have peanut allergy. OBJECTIVE: We sought to study the occurrence of peanut allergy in patients allergic to birch pollen and characterized the Bet v 1-homologous peanut allergen Ara h 8. METHODS: Recombinant Ara h 8 was cloned with degenerated primers and expressed in Escherichia coli. Nine Swiss and 11 Dutch patients with peanut and birch pollen allergy and a positive double-blind, placebo-controlled food challenge result to peanut were investigated for IgE reactivity to birch pollen and purified peanut allergens and cross-reactivity between birch and peanut. Ara h 8 stability against digestion and roasting was assessed by means of RAST inhibition. The IgE cross-linking potency of Ara h 8 was tested on the basis of basophil histamine release. RESULTS: During double-blind, placebo-controlled food challenge, all patients experienced symptoms in the oral cavity, progressing to more severe symptoms in 40% of patients. CAP-FEIA detected recombinant (r) Ara h 8-specific IgE in 85%. IgE binding to Ara h 8 was inhibited by Bet v 1 in peanut extract immunoblotting and in RAST inhibition. In EAST inhibition recombinant rAra h 8 inhibited IgE binding to peanut in 4 of 7 tested patient sera. Antipeanut response was dominated by Ara h 8 in 12 of 17 tested patients. Furthermore, our results demonstrate a low stability of Ara h 8 to roasting and no stability to gastric digestion. Basophil histamine release with rAra h 8 was more than 20% in 5 of 7 tested sera. CONCLUSIONS: Peanut allergy might be mediated in a subgroup of our patients by means of cross-reaction of Bet v 1 with the homologous peanut allergen Ara h 8.