Allergic rhinitis and school performance

Allergic rhinitis is presently the most common chronic disorder in the pediatric population. It can affect sleep at night and cause daytime sleepiness, with school absenteeism, "presenteeism" or inattention, mood disturbances and psychosocial problems. All this in turn can contribute to reduce school performance. The correct treatment of allergic rhinitis can improve school performance, though the first generation antihistamines have unacceptable central and anticholinergic effects that can actually worsen the situation. The second generation antihistamines constitute the drug treatment of choice for allergic rhinitis in children. Vasoconstrictors should not be used in pediatric patients, due to their unpredictable pharmacokinetics and very narrow therapeutic margin. Intranasal corticoids could improve school performance in some patients, by reducing nose block or congestion, the nocturnal sleep disturbances, and daytime sleepiness. Concrete studies of the impact of chromones, anticholinergic agents, antileukotrienes and immunotherapy upon school performance are lacking.

Genetic aspects of allergic rhinitis

The development of allergic rhinitis entails a complex interaction between genetic predisposition and environmental exposure to different factors, of which the most important is the implicated allergen. There is a clear hereditary component in allergic rhinitis that has been well corroborated by segregation studies and investigations in twins. From the strictly genetic perspective, it is believed that the disease may be the result of the interaction of different genetic alterations, each of which would contribute a small defect. In recent years, considerable attention has focused on the genes that may be implicated in allergic rhinitis. A number of genomic searches have been made, yielding different chromosomal associations--the most repeated being those involving chromosomes 2, 3, 4 and 9. Single-nucleotide polymorphism studies involving genes encoding for molecules implicated in the pathogenesis of allergic rhinitis have also been made. Such molecules comprise chemokines and their receptors, interleukins and their receptors, eosinophil peroxidase and leukotrienes, among others.

Molecular diagnosis in allergology: application of the microarray technique

Recombinant and purified allergens are currently available for determining specific IgE targeted to different allergenic components. In this way it is possible to diagnose the sensitization profile of each individual patient. The microarray technique makes it possible to determine specific IgE against multiple allergens simultaneously in one same patient, with a minimum amount of serum, and even allows the determination of IgG and IgM against the same allergens in one same serum sample. Microarray procedures are being developed not only for the determination of antibodies but also for cell activation tests. In addition, microarray technology will help explain cross-reactions, and will facilitate the evaluation of subjects in which skin tests cannot be performed. These techniques will allow a great step forward in the development of immunotherapy specifically targeted to the sensitizations found in each individual patient, yielding especially hypoallergenic forms of great immunogenic capacity, and thus improving the safety and efficacy of immunotherapy. Lastly, microarrays will improve our understanding of the physiopathology of allergic diseases.

Stress and allergy

In recent years it has been seen that the nervous and immune systems regulate each other reciprocally, thus giving rise to a new field of study known as psychoneuroimmunology. Stress is defined as a general body response to initially threatening external or internal demands, involving the mobilization of physiological and psychological resources to deal with them. In other words, stress is characterized by an imbalance between body demands and the capacity of the body to cope with them. The persistence of such a situation gives rise to chronic stress, which is the subject of the present study, considering its repercussions upon different organs and systems, with special emphasis on the immune system and--within the latter--upon the implications in relation to allergic disease. Activation of the neuroendocrine and sympathetic systems through catecholamine and cortisol secretion exerts an influence upon the immune system, modifying the balance between Th1/Th2 response in favor of Th2 action. It is not possible to affirm that chronic stress is intrinsically able to cause allergy, though the evidence of different studies suggests than in genetically susceptible individuals, such stress may favor the appearance of allergic disease on one hand, and complicate the control of existing allergy on the other.

Allergic conjunctivitis and H1 antihistamines

Allergic conjunctivitis is the most common form of ophthalmological allergy. Eye symptoms are one of the main and most frequent reasons for consultation among patients with allergic rhinoconjunctivitis, which in turn is the most common reason for visiting the allergologist, according to the Alergológica 2005 study. Itching is the key symptom of allergic conjunctivitis, and its relief is the principal objective of the broad range of treatment options available. Topical antihistamines with multiple actions (mast cell stabilization, and antiinflammatory and antihistaminic actions) are probably the best treatment option, thanks to their rapid action, safety and convenience of use. However, oral antihistamines (preferentially second generation drugs) can also play an important role, since they are of established efficacy and offer adequate treatment of the nasal symptoms that tend to accompany the ocular manifestations of allergic rhinoconjunctivitis. Models of allergic conjunctivitis are useful for investigational purposes and for advancing our knowledge of allergic reactions. Advances in the study of the physiopathology of ocular allergy allow us to introduce new therapeutic options for the management of such allergic reactions, thanks to the findings derived from models of this kind. The present review provides an update to the published data on allergic conjunctivitis and the current role of both topical and ocular antihistamines in treating the disorder.

Component-resolved in vitro diagnosis in peach-allergic patients

BACKGROUND

The in vitro diagnosis of pollen-related food allergy presents low specificity and reproducibility with many conventional extracts. This can be improved using natural purified allergens, recombinant purified allergens, or both.

OBJECTIVE

We compared specific immunoglobulin (Ig) E determination (slgE), the basophil activation test (BAT), the histamine release test (HRT), and the cellular allergen stimulation test (CAST) using natural and recombinant allergens in the diagnosis of peach allergy.

METHODS

Thirty-two peach allergic patients were studied. Skin prick tests were performed with commercial peach and extract with Mal d 1, nPru p 3, and profilin (nPho d 2). slgE, BAT, CAST, and HRT were determined using rPru p 3, rMal d 3, rBet v 1, rMal d 1, and rMal d 4.

RESULTS

Agreement between the techniques was good with all the allergens, except HRT with rMal d 1 and rMal d 4. With rPru p 3, slgE, CAST, BAT, and HRT showed sensitivity values of 88%, 81%, 72%, and 69% and specificity values of 100%, 93%, 97%, and 83%, respectively. In patients with systemic symptoms or contact urticaria, the values were 100%, 85%, 81%, and 81%. In patients with oral allergy syndrome, sensitivity to profilins or homologues of Bet v 1 was detected in 100% of the cases by all the techniques, except by HRT with rMal d 1, which detected 66% of the cases.

CONCLUSIONS

The use of single allergens in the in vitro diagnosis of peach allergy by specific IgE determination, BAT, and CAST offers high specificity and sensitivity, with better results than the HRT.

Chronic urticaria: do urticaria nonexperts implement treatment guidelines? A survey of adherence to published guidelines by nonexperts

BACKGROUND

Guidelines including level of evidence and grade of recommendation were recently published for chronic urticaria (CU).

OBJECTIVES

To describe the therapeutic approach in patients with CU, and to depict how recent guidelines are implemented in the daily practice of management of CU.

METHODS

We performed a cross-sectional multicentre study through a questionnaire answered by 139 specialists. In total, 695 patients were evaluated, mean+/-SD age 42.3+/-15 years, 62.1% women. Of the patients, 168 were treated by an allergist, 473 by a dermatologist and in 54 cases the specialist was not stated. The drug prescribed was the main variable, and chi2 and Fisher's tests were utilized for the statistical analysis.

RESULTS

Nonsedating anti-H1 antihistamines taken regularly were the most common drugs prescribed, followed by nonsedating anti-H1 antihistamines taken as needed, corticosteroids, sedating antihistamines taken regularly, sedating antihistamines taken as needed, anti-H2 antihistamines, leukotriene antagonists, ciclosporin and doxepin. Nonsedating antihistamines plus corticosteroids was the most frequent drug combination prescribed. When comparing between allergists and dermatologists we found a positive and significant correlation only between prescription of cetirizine, dexchlorfeniramine, leukotriene antagonists and anti-H2 antihistamines and being treated by an allergist. A positive correlation was found with desloratadine and being seen by a dermatologist. We did not find any difference in CU management in the rest of the treatments studied.

CONCLUSIONS

It is surprising that a large amount of sedating antihistamines was prescribed. In many instances these were prescribed as needed. This fact could have a negative impact on urticaria control and patient satisfaction. It seems difficult for the nonexpert to differentiate between CU and any kind of physical urticaria.

Chronic ouabain treatment increases the contribution of nitric oxide to endothelium-dependent relaxation

The aim of this study was to analyze the contribution of nitric oxide, prostacyclin and endothelium-dependent hyperpolarizing factor to endothelium-dependent vasodilation induced by acetylcholine in rat aorta from control and ouabain-induced hypertensive rats. Preincubation with the nitric oxide synthase inhibitor N-omega-nitro-L-arginine methyl esther (L-NAME) inhibited the vasodilator response to acetylcholine in segments from both groups but to a greater extent in segments from ouabain-treated rats. Basal and acetylcholine-induced nitric oxide release were higher in segments from ouabain-treated rats. Preincubation with the prostacyclin synthesis inhibitor tranylcypromine or with the cyclooxygenase inhibitor indomethacin inhibited the vasodilator response to acetylcholine in aortic segments from both groups. The Ca2+-dependent potassium channel blocker charybdotoxin inhibited the vasodilator response to acetylcholine only in segments from control rats. These results indicate that hypertension induced by chronic ouabain treatment is accompanied by increased endothelial nitric oxide participation and impaired endothelium-dependent hyperpolarizing factor contribution in acetylcholine-induced relaxation. These effects might explain the lack of effect of ouabain treatment on acetylcholine responses in rat aorta.

Exercise-induced hypersensitivity syndromes in recreational and competitive athletes: a PRACTALL consensus report (what the general practitioner should know about sports and allergy)

Exercise-induced (EI) hypersensitivity disorders are significant problems for both recreational and competitive athletes. These include EI-asthma, EI-bronchoconstriction, EI-rhinitis, EI-anaphylaxis and EI-urticaria. A group of experts from the European Academy of Allergology and Clinical Immunology and the American Academy of Allergy Asthma and Immunology met to discuss the pathogenesis of these disorders and how to diagnose and treat them, and then to develop a consensus report. Key words (exercise with asthma, bronchoconstriction, rhinitis, urticaria or anaphylaxis) were used to search Medline, the Cochrane database and related websites through February 2008 to obtain pertinent information which, along with personal reference databases and institutional experience with these disorders, were used to develop this report. The goal is to provide physicians with guidance in the diagnosis, understanding and management of EI-hypersensitivity disorders to enable their patients to safely return to exercise-related activities.

Multiplexed Assays by High-Content Imaging for Assessment of GPCR Activity

G-protein-coupled receptors (GPCR) participate in many disease pathways and represent the largest family of therapeutic targets. Thus, great investments are made to discover drugs modulating GPCR-mediated events. Among functional assays for screening GPCRs, the Transfluor®imaging assay is based on redistribution of cytosolic β-arrestin to an activated GPCR and has become widely used in high-content screening. However, assessing Transfluor®alone has limitations: relying on a single mechanistic step of β-arrestin redistribution during GPCR activation, providing no information on the stimulated GPCR's intracellular fate, and using only a single fluorescent color (green fluorescent protein). Taking full advantage of high-content imaging to screen approximately 2000 compounds, the authors multifplexed the Transfluor®assay with an immunofluorescence-based quantification of GPCR internalization. This approach identified and classified 377 compounds interfering with agonist-induced activation of the Transfluor®assay, receptor internalization, or both. In addition, a subset of compounds was analyzed for their performance across imaging, cell-based calcium release (fluorometric imaging plate reader [FLIPR]), and biochemical receptor binding assays (scintillation proximity assay). This indicated that the imaging assays have even better predictive power for direct inhibition of receptor binding than the FLIPR assay. In conclusion, compounds inducing unique responses can suggest novel mechanisms of action and be used as tools to study GPCR activation and internalization. ( Journal of Biomolecular Screening 2008:449-455)

Non-invasive ventilation in the weaning process

Patients with chronic airflow obstruction and difficulty in weaning from mechanical ventilation are at increased risk for intubation-associated complications and mortality because of prolonged invasive mechanical ventilation. Non-invasive ventilation (NIV) may avert most of the pathophysiologic mechanisms associated with weaning failure in these patients. Several randomised controlled trials have shown that the use of NIV in order to advance extubation in difficult patients can result in reduced periods of endotracheal intubation, complication rates and survival. The published data with the outcome as a primary variable are nearly exclusively from patients who had pre-existing lung disease. In addition, the patients were hemodynamically stable, with a normal level of consciousness, no fever and a preserved cough reflex. The use of NIV in the management of respiratory failure after extubation did not show clinical benefits, although clinical trials included a small proportion of chronic respiratory patients. In contrast, NIV immediately after extubation is effective in avoiding respiratory failure after extubation in patients at risk for this complication, particularly those with chronic respiratory disorders and hypercapnic respiratory failure.

Light-driven novel properties of TiO2-modified polypropylene-based nanocomposite films

Nanocomposite films obtained by TiO2 incorporation into a polypropylene (PP) polymer matrix were prepared via a straightforward melting process. The structural characteristics of the nanocomposite materials were examined by a multitechnique approach showing the outstanding morphological uniformity of the films. TiO2 incorporation into the polymer matrix renders self-sterilized and self-degradable materials which showed an impressive performance against gram-positive, gram-negative, coccus and yeast micro-organisms. Optimization of the novel properties of TiO2-PP nanocomposite films is reached with a 2 wt% of oxide content loading. The physico-chemical bases of this optimum are discussed.

Orchidectomy increases the formation of non-endothelial thromboxane A2 and modulates its role in the electrical field stimulation-induced response in rat mesenteric artery

The aim of this study was to analyze whether endogenous male sex hormones influence the release of thromboxane A2(TXA2) and its role in the electrical field stimulation (EFS)-induced response, as well as the mechanism involved. For this purpose, endothelium-denuded mesenteric arteries from control and orchidectomized male Sprague-Dawley rats were used to measure TXA2 release; EFS-induced response, nitric oxide (NO), norepinephrine (NA), and prostaglandin (PG) I2 release were also measured in the presence of the TXA2 synthesis inhibitor furegrelate. Orchidectomy increased basal and EFS-induced TXA2 release. Furegrelate decreased the EFS-induced contraction in arteries from control rats, but did not modify it in arteries from orchidectomized rats. The EFS-induced neuronal NO release and vasodilator response were increased by furegrelate in arteries from control rats, but were not modified in arteries from orchidectomized rats. Furegrelate did not modify the EFS-induced NA release or vasoconstrictor response in arteries from either control or orchidectomized rats. The EFS-induced PGI2 release was not modified by furegrelate in arteries from control rats, but was increased in arteries from orchidectomized rats. The results of the present study show that endogenous male sex hormone deprivation i) increases non-endothelial TXA2 release and ii) regulates the effect of endogenous TXA2 on the EFS-induced response through different mechanisms that, at the least, involve the NO and PGI2 systems. In arteries from control rats, inhibition of TXA2 formation decreases the EFS-induced response by increasing neuronal NO release. In arteries from orchidectomized rats, the EFS-induced response is unaltered after the inhibition of TXA2 formation, by increasing PGI2 release.

Effect of oat's soluble fibre (β-glucan) as a fat replacer on physical, chemical, microbiological and sensory properties of low-fat beef patties

This study evaluated the effect of adding oat fibre source of β-glucan (13.45%) on physical, chemical, microbiological and sensory traits of low-fat (<10%) beef patties as compared to 20% fat control patties. Significant (p<0.05) improvements in cooking yield (74.19%), and retentions of fat (79.74%) and moisture (48.41%) of low-fat patties were attributed to the water binding ability of β-glucan. Because of larger water retentions moisture contents of raw and cooked low-fat patties were higher (p<0.05) than those of the control patties. Cholesterol content was similar across formulations. Low-fat and control beef patties remained stable in microbiological quality during 60days frozen storage. Low-fat patties were found to be of lower degree of likeness in the taste but juicer than control (p<0.05). Besides appearance, tenderness and colour were not affected by the addition of oat's soluble fibre. Oat fibre can be used successfully as a fat substitute in low-fat beef patties.

Adaptation and validation of the Spanish version of the Chronic Urticaria Quality of Life Questionnaire (CU-Q2oL)

OBJECTIVES

The aim of this study was to develop a Spanish version of the Chronic Urticaria Quality of Life Questionnaire (CU-Q2oL) and to test its acceptability, reliability, validity, and sensitivity to change.

METHODS

Forward and back translation by bilingual translators followed by pilot testing in patients with urticaria was used to adapt the questionnaire. The Spanish version of the CU-Q2oL was self-administered alongside the Skindex-29 in an observational, longitudinal, multicenter study. Feasibility was assessed by analyzing missing responses and ceiling and floor effects. Reliability was tested by examining internal consistency (Cronbach alpha). Construct validity was analyzed by examining convergent and discriminant validity with the Skindex-29 and by evaluating the ability of the CU-Q2oL to discriminate between patients according to a clinical classification of severity. Sensitivity to change was analyzed in a subgroup of patients who completed a second visit 4 weeks after baseline.

RESULTS

A total of 695 patients were included in the analysis. Mean (SD) age was 42.4 (15.0) years and 62.1% of the sample was female. All of the items on the CU-Q2oL were answered by 91.9% of the sample. Over 15% of patients scored at the floor (best possible health) on 5 of the 6 dimensions. Cronbach alpha coefficients were > 0.80 for all dimensions of the CU-Q2oL, and 0.86 for the overall score. Construct validity was supported by correlations between the CU-Q2oL and the Skindex-29, which generally fulfilled hypotheses, and by the questionnaire's ability to discriminate between groups with different severities of urticaria.The questionnaire was sensitive to change, with an effect size of 1.0 for the overall score in patients reporting an improvement on the health transition scale.

CONCLUSIONS

The Spanish version of the CU-Q2oL has shown satisfactory reliability, validity, and sensitivity to change. It is suitable for use as an outcome measure for chronic urticaria patients in clinical and research settings.

Health-related quality of life in allergic rhinitis: comparing the short form ESPRINT-15 and MiniRQLQ questionnaires

BACKGROUND

We compared the psychometric properties of the ESPRINT-15, the short form of a new Spanish instrument to measure health-related quality of life in allergic rhinitis (AR) patients, with those of the Mini-Rhinoconjunctivitis Quality of Life Questionnaire (MiniRQLQ).

METHODS

The questionnaires were compared in Spanish patients with intermittent allergic rhinitis (IAR) or persistent AR in a prospective, observational study. Floor and ceiling effects, internal consistency (Cronbach's alpha), test-retest reliability (intraclass correlation coefficient; ICC), convergent and known groups validity, and sensitivity to change (standardized response means; SRMs) were compared.

RESULTS

In terms of content, while the MiniRQLQ has a dimension covering practical problems and places more emphasis on symptoms, the ESPRINT-15 has two dimensions (Sleep and Psychological impact) which are not included in the MiniRQLQ. In the validation study, 400 patients were included and 59% of the sample had persistent AR. There were no significant floor or ceiling effects on any dimension on either questionnaire. Cronbach's alpha values for the ESPRINT-15 and MiniRQLQ overall scores were 0.92 and 0.90, respectively. In 48 clinically stable patients, ICCs were 0.80 and 0.77, respectively. Both instruments discriminated between patients with IAR and persistent AR. Correlations with symptom scores and generic measures were moderate to strong. SRMs for overall scores and individual dimensions on the two questionnaires in the 197 patients reporting a change in health status ranged from 0.7 to 1.3.

CONCLUSIONS

Both questionnaires performed well in psychometric terms. The ESPRINT-15 is particularly recommended for use in Spanish-speaking populations.

Sequential measurements of procalcitonin levels in diagnosing ventilator-associated pneumonia

The utility of procalcitonin levels to improve the accuracy of clinical and microbiological parameters in diagnosing ventilator-associated pneumonia (VAP) was evaluated. Sequential measurement of procalcitonin and C-reactive protein levels and the calculation of the simplified Clinical Pulmonary Infection Scores (CPIS) were performed in 44 patients mechanically-ventilated for >48 h with neither active infection for the duration or suspicion of VAP. Patients who developed extrapulmonary infection were excluded. In total, 20 cases were suspected of having VAP and diagnosis was microbiologically confirmed in nine. In patients with confirmed VAP, procalcitonin levels were higher than in those without VAP. C-reactive protein levels and CPIS were lower in patients without suspected VAP, but could not discriminate confirmed and nonconfirmed suspicion of VAP. The best sensitivity and specificity (78 and 97%, respectively) corresponded to procalcitonin. The CPIS resulted in the same sensitivity, but had a lower specificity (80%). C-reactive protein had the worst sensitivity (56%), but a good specificity (91%). A CPIS >or=6 combined with serum levels of procalcitonin >or=2.99 ng.mL(-1) did not improve the sensitivity (67%), but resulted in 100% specificity. Procalcitonin might be useful in the diagnosis of ventilator-associated pneumonia. Combined values of Clinical Pulmonary Infection Scores and procalcitonin below the cut-off points excluded false-positive diagnoses of ventilator-associated pneumonia.