Mass spectrometry-based quantification of immunostimulatory gliadin proteins and peptides in coloured wheat varieties: Implications for Celiac Disease

Pigmented wheat varieties (Triticum aestivum spp.) are getting increasingly popular in modern nutrition and thoroughly researched for their functional and nutraceutical value. The colour of these wheat grains is caused by the expression of natural pigments, including carotenoids and anthocyanins, that can be restricted to either the endosperm, pericarp and/or aleurone layers. While contrasts in phytochemical synthesis give rise to variations among purple, blue, dark and yellow grain's antioxidant and radical scavenging capacities, little is known about their influence on gluten proteins expression, digestibility and immunogenic potential in a Celiac Disease (CD) framework. Herein, it has been found that the expression profile and immunogenic properties of gliadin proteins in pigmented wheat grains might be affected by anthocyanins and carotenoids upregulation, and that the spectra of peptide released upon simulated gastrointestinal digestion is also significantly different. Interestingly, anthocyanin accumulation, as opposed to carotenoids, correlated with a lower immunogenicity and toxicity of gliadins at both protein and peptide levels. Altogether, this study provides first-level evidence on the impact modern breeding practices, seeking higher expression levels of health promoting phytochemicals at the grain level, may have on wheat crops functionality and CD tolerability.

Assessing the risks of capecitabine and its active metabolite 5-fluorouracil to freshwater biota

Capecitabine (CAP, prodrug) and 5-fluorouracil (5-FU, its active metabolite) are two of the most prominent cytostatics, for which no clear picture can be drawn regarding potential concentrations of effect for freshwater biota, with CAP being grouped in the least studied cytostatic, whereas 5-FU has been classified as of no and of high environmental risk. Accordingly, the present work aimed to assess the ecotoxicity of CAP and 5-FU in three freshwater species, which included a 72-h assay with the producer Raphidocelis subcapitata; a 96-h assay with the invertebrate secondary consumer Hydra viridissima; and a 96-h assay with embryos of the vertebrate secondary consumer Danio rerio. The following endpoints were monitored: yield and population growth rate for the algae; mortality, morphological alterations, and post-exposure feeding rates for the cnidarian; and mortality, hatching, and malformations for the fish. Overall, organisms' sensitivity to CAP decreased in the following order: R. subcapitata > H. viridissima > D. rerio, whereas for 5-FU, it decreased in the following order: H. viridissima > D. rerio > R. subcapitata. For CAP, no median lethal effective concentrations (LC/EC₅₀) were possible to compute for D. rerio, with no significant mortality or malformations registered in embryos exposed at concentrations up to 800 mg L^-1. For R. subcapitata, the EC₅₀s were 0.077 and 0.63 mg L^-1 for yield and growth rate, respectively, and for H. viridissima, the EC_50,30 min for feeding was 22.0 mg L^-1. For 5-FU, no EC_50s could be computed for R. subcapitata, whilst the EC_50s for H. viridissima mortality and feeding were 55.4 and 67.9 mg L^-1, respectively, and for D. rerio, the LC_50,96 h and EC_50,96 h (hatching and abnormalities) were 4546, 4100, and 2459 mg L^-1, respectively. Assuming similar modes of action for both compounds and their co-occurrence, the combined risk quotient of the two chemicals was determined to be 7.97, which represents a risk for freshwater biota. Anticipating the increased consumption of these compounds and cancer development trends worldwide, these impacts may be further aggravated.

Contributions towards the hazard evaluation of two widely used cytostatic drugs

Cytostatic drugs are one of the most important therapeutic options for cancer, a disease that is expected to affect 29 million individuals by 2040. After being excreted, cytostatics reach wastewater treatment plants (WWTPs), which are unable to efficiently remove them, and consequently, they will be released into the aquatic environment. Due to the highly toxic properties of cytostatics, it is particularly relevant to evaluate their potential ecological risk. Yet, cytostatics toxicity data is still not available for various species. In this work, the ecotoxicity of two widely consumed cytostatics, cyclophosphamide (CYP-as a model cytostatic) and mycophenolic acid (MPA-as a priority cytostatic), was evaluated on three freshwater species-Raphidocelis subcapitata, Brachionus calyciflorus, and Danio rerio, and the risk quotient (RQ) was assessed. Both drugs significantly affected the yield and growth inhibition of the microalgae, while for rotifers, the least sensitive species, only significant effects were registered for CYP. These drugs also caused significant effects on the mortality and morphological abnormalities on zebrafish. The estimation of the RQ discloses that CYP seems to pose a low risk to aquatic biota while MPA poses a very high risk. Altogether, these results emphasize the need for more complete environmental risk assessments, to properly prioritize and rank cytostatics according to their potentially toxic effects on the environment and aquatic biota.

P–475 The mediator role of infertility-related psychological inflexibility in the relationship between infertility-stress domains and psychopathological symptoms

Study question

Does infertility-related psychological inflexibility play a role in the relationship between infertility-related stress domains and psychopathological symptoms (depression, anxiety)?

Summary answer

Infertility-related psychological inflexibility mediated the relationship between infertility-related stress domains and depression. There were no effects between infertility-related stress domains and anxiety symptoms.

What is known already

The emotional impact of infertility may include anxiety and depressive symptoms and these seem to be related to stress. Beliefs about the importance of parenthood (need for parenthood) and rejection of a childfree lifestyle, as well as the impact of infertility in several life areas (social, sexual, and relationship) are conceptually considered two infertility-related stress domains. Although the relationship between infertility-related stress and psychopathological symptoms has been previously recognized, the mechanism underlying this relationship remains undetermined. Psychological inflexibility has been pointed as a core transdiagnostic process contributing to the development and maintenance of several psychological difficulties.

Study design, size, duration

Cross-sectional study. Participants were recruited through the Associação Portuguesa de Fertilidade (patients’ association). Inclusion criteria were age (18 years or older) and an infertility medical diagnosis. Data were collected online through self-report instruments between June and December 2019. Participants/materials, setting, methods: A sample comprising 287 women pursuing infertility medical treatment (at different stages) completed online a sociodemographic questionnaire, the depression and anxiety subscales of the Depression, Anxiety and Stress Scales (DASS – 21), the Psychological Inflexibility Scale - Infertility (PIS-I), and the Fertility Problem Inventory (FPI). Descriptive and correlational analyses were computed through SPSS v. 26, and path analyses were estimated in AMOS (v. 24) with bootstrap procedures (2000 samples).

Main results and the role of chance

Correlation analyses revealed that FPI domains (importance of parenthood and impact on life domains), depressive and anxiety symptoms were significantly and positively associated with PIS-I. A mediation analysis was conducted to examine whether PIS-I mediated the effect of FPI domains on depressive and anxiety symptoms. Paths showing not to be statistically significant were removed. This model showed a good fit to the empirical data: χ2(4) = 1.59, p = .810, CMIN/DF = .40; TLI = 1.00; CFI = 1.00; RMSEA = .00, 95% CI = .00 to .06. The effect of the importance of parenthood on depressive symptoms revealed to be both direct (b = .03; SEb = .01; Z = 2.46; p = .014; β= .15) and partially mediated by the PIS-I (b = .31, 95% CI = .24 to .37, p = .018). The effect of the impact of infertility in several life areason depressive symptoms was fully mediated by PIS-I (b = .15, 95% CI = .10 to .21, p = .008). This model explained 43% of the total variance of depressive symptoms. No significant effects were found for anxiety symptoms.

Limitations, reasons for caution

Participants were at different stages of their fertility treatment. Data collection was completed online and this tends to recruit participants with more access to online platforms. Results rely on cross-sectional and self-report data.

Wider implications of the findings: Results suggest the relevance of targeting processes encompassing psychological inflexibility, such as cognitive fusion, experiential avoidance, conceptualized self, conceptualized past and future, lack of values clarity, and inability to commit with values-driven actions, in psychological interventions designed for women with infertility.

Trial registration number

N/A.

P–491 The mediator role of pain-related psychological inflexibility in the relationship between psychopathological symptoms and pain intensity in endometriosis

Study question

Does pain-related psychological inflexibility play a role in the relationship between psychopathological symptoms (depression, anxiety, stress) and pain intensity in women with endometriosis?

Summary answer

Pain-related psychological inflexibility acts as a mediator exclusively between depressive symptoms and pain intensity. Psychopathological symptoms did not reveal a direct effect on pain intensity.

What is known already

Endometriosis is a chronic and incapacitating condition frequently involving the experience of pain (e.g., dysmenorrhea, ovulation pain, dyspareunia, chronic pelvic pain). Women dealing with endometriosis may present impaired health-related quality of life and psychological distress, with depressive, anxiety, and stress symptoms being commonly reported. Pain-related psychological inflexibility involves emotion regulation processes, such as avoidance of pain and cognitive fusion with pain. Cognitive and behavioural processes influence the relationship between pain and psychopathological symptoms, and pain-related psychological inflexibility showed to be an underlying mechanism in this relationship.

Study design, size, duration

Cross-sectional study. Participants’ recruitment was completed through the Associação Portuguesa de Apoio a Mulheres com Endometriose and the Associação Portuguesa de Fertilidade (endometriosis and infertility patients’ associations). Inclusion criteria were age (18 years or older) and an endometriosis medical diagnosis (self-reported). Data collection occurred between February 2018 and May 2018.

Participants/materials, setting, methods

A sample encompassing 209 women with an endometriosis diagnosis completed online a sociodemographic questionnaire, the Depression, Anxiety and Stress Scales (DASS – 21), the Numeric Pain Rating Scale (NPRS), and the Psychological Inflexibility in Pain Scale (PIPS-PT). Descriptive and correlational analyses were carried out using SPSS v. 26, and path analyses were estimated in AMOS (v. 24) with bootstrap procedures (2000 samples).

Main results and the role of chance

Participants’ age ranged from 18 to 50 years old with a mean of 34.03 (SD = 6.44) years. The majority of participants were married (n = 112; 53.6%), followed by single (n = 54; 25.8%). Regarding years of education, a mean of 14.62 years (SD = 2.80) was found. Participants reported that their endometriosis diagnosis had been established for 4.55 years (SD = 4.56). Correlation analyses showed that depressive, anxiety and stress symptoms were significantly and positively associated with pain intensity and pain-related psychological inflexibility. A mediation analysis was conducted to examine whether pain-related psychological inflexibility mediated the effect of psychopathological symptoms on pain intensity. Paths showing not to be statistically significant were removed. The final model defining an effect of depressive symptoms on pain intensity mediated by pain-related psychological inflexibility explained 26% of the variance. This model showed a good fit to the empirical data: χ2(5) = 10.75, p = .057, CMIN/DF = 2.15; TLI = .98; CFI = .99; RMSEA = .07, 95% CI = .00 to .14. Depressive symptoms predicted elevated pain intensity fully through higher pain-related psychological inflexibility (b = .05; SEb = .01; Z = 8.45; p < .001; β= .51).

Limitations, reasons for caution

Although path analysis is a powerful statistical technique, our findings rely on cross-sectional and self-report data. The study was disseminated through patients’ associations, limiting the inclusion of people who do get in touch with such organizations. Moreover, online recruitment tends to recruit participants with more access to online platforms.

Wider implications of the findings: Pain-related psychological inflexibility seems to be a relevant construct to be addressed in the psychological assessment of women dealing with endometriosis. Furthermore, results suggest the relevance of targeting emotion regulation processes, and not only focus on reducing pain, in pain management interventions.

Trial registration number

N/A.

Ice therapy: cool, current and complicated

This is the fourth Capsule review article provided by the WSAVA Global Pain Council and which discusses the use of ice or cold therapy as a non-pharmacologic modality for pain control in small animal practice. The physiological effects of cold therapy on tissues, receptors and ion channels are discussed; as well as indications, recommendations for, and limitations of use.

Intraperitoneal and incisional analgesia in small animals: simple, cost-effective techniques

The World Small Animal Veterinary Association Global Pain Council (WSAVA-GPC) has recently published its first "capsule review" by Monteiro et al. These are short articles that present a brief assessment of the scientific evidence and practical recommendations on important, and sometimes controversial, subjects in pain management. The capsules will be published regularly in the Journal of Small Animal Practice, the official journal of the WSAVA. This second article discusses the use of intraperitoneal and incisional analgesia in small animal practice, including their limitations and recommendations by the authors.

Long-term use of non-steroidal anti-inflammatory drugs in cats with chronic kidney disease: from controversy to optimism

This is the first of a series of capsule reviews published by the World Small Animal Veterinary Association - Global Pain Council (WSAVA-GPC). Each of these short articles provides a brisk assessment of the scientific evidence in specific aspects of pain management, including analgesic techniques, recommendations and controversies surrounding their use. In this first capsule review, the scientific evidence available on the long-term use of non-steroidal anti-inflammatory drugs in cats with concomitant chronic pain and chronic kidney disease is discussed.

Sperm donation and surrogacy from a male perspective

Introduction

Societal changes in the last decades led to the arise of new paradigms on gender equity. Studies addressing fertility/infertility issues have been conducted mainly in women and in this research area, male partners have deserved less attention. More recently there has been a major focus on the idea that fertility/infertility aspects have to be conceptualized from a couples’ perspective.

Goals

The current study sought to explore attitudes towards gamete donation and surrogacy in a sample of young men in reproductive age.

Methods

A total of 111 males with ages ranging from 18 to 40 years old and without children completed an online questionnaire addressing attitudes towards gamete donation and surrogacy.

Results

The majority of participants (77.3%) would be willing to donate their sperm, and their main motivation for doing that would be to feel “happy to help a couple struggling to have a child”. Participants stated that the likelihood of donating would increase if they were able to attend counseling, to complete the procedure in an IVF center located in their residence area, and being provided with more information about infertility. Regarding surrogacy 82% are in favor of this procedure legalization and 49.5% would be willing to use it if they needed.

Conclusion

Men showed a positive attitude towards sperm donation and surrogacy, emphasizing the importance of counseling and information availability on these topics. This may suggest that they are willing to get involved when fertility issues are addressed.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Effects of the naturally-occurring contaminant microcystins on the Azolla filiculoides-Anabaena azollae symbiosis

Harmful algal blooms (HABs) contaminate aquatic ecosystems and are responsible for animal poisoning worldwide. We conducted a toxicity test with the aquatic fern and the biofertilizer, Azolla filiculoides. The sporophytes were exposed to three concentrations (0.01, 0.1 and 1μgmL(-1)) of a microcystin (MC) cyanobacterial crude extract and purified MC-LR. The growth of A. filiculoides decreased only at 1μgmL(-1) crude extract concentration while with MC-LR it decreased at all the tested concentrations, indicating that the presence of other compounds in the crude extract altered toxicity and stimulated the fern growth at lower concentrations (0.01 and 0.1μgmL(-1)). Both phycoerythrocyanin and allophycocyanin levels decreased in all the concentrations of crude extract and MC-LR. The phycocyanin had a marked increase at 0.1μgmL(-1) crude extract concentration and a marked decrease at 1μgmL(-1) MC-LR concentration. These changes in the phycobiliprotein content indicate a shift in the antenna pigments of the cyanobionts of A. filiculoides. The changes in two oxidative stress enzymes, glutathione reductase for the crude extract assay and glutathione peroxidase for MC-LR assay, points towards the induction of stress defense responses. The low bioconcentration factor in both crude extract and MC-LR treatments can suggest the low uptake of microcystins, and indicates that the aquatic fern can be used as a biofertilizer and as animal feed but is not suitable for MC phytoremediation.

Surface Roughness of Composite Resins after Simulated Toothbrushing with Different Dentifrices

BACKGROUND

The aim of the study was to evaluate, in vitro, the surface roughness of two composite resins submitted to simulated toothbrushing with three different dentifrices.

MATERIALS AND METHODS

Totally, 36 samples of Z350XT and 36 samples of Empress Direct were built and randomly divided into three groups (n = 12) according to the dentifrice used (Oral-B Pro-Health Whitening [OBW], Colgate Sensitive Pro-Relief [CS], Colgate Total Clean Mint 12 [CT12]). The samples were submitted to 5,000, 10,000 or 20,000 cycles of simulated toothbrushing. After each simulated period, the surface roughness of the samples was measured using a roughness tester.

RESULTS

According to three-way analysis of variance, dentifrice (P = 0.044) and brushing time (P = 0.000) were significant. The composite resin was not significant (P = 0.381) and the interaction among the factors was not significant (P > 0.05). The mean values of the surface roughness (µm) followed by the same letter represent no statistical difference by Tukey's post-hoc test (P <0.05): Dentifrice: CT12 = 0.269(a); CS Pro- Relief = 0.300(ab); OBW = 0.390(b). Brushing time: Baseline = 0,046ª; 5,000 cycles = 0.297(b); 10,000 cycles = 0.354(b); 20,000 cycles = 0.584(c).

CONCLUSION

Z350 XT and Empress Direct presented similar surface roughness after all cycles of simulated toothbrushing. The higher the brushing time, the higher the surface roughness of composite resins. The dentifrice OBW caused a higher surface roughness in both composite resins.

197 INDUCED PLURIPOTENT STEM CELLS (iPS) DERIVED FROM EQUINE UMBILICAL CORD CELLS USING LENTIVIRUS VECTOR Stemcca

Research on induced pluripotent stem cells (iPS) emerged to overcome the limitations of embryonic stem cells, such as ethical issues, security, compatibility, and availability. The nuclear reprogramming induced by viral vectors aims to induce differentiated cells to an embryonic pluripotent state. The iPS cells can be generated using retroviral vector expressing Oct4, Sox2, Klf4 and c-Myc, but produces much genomic integration (GI) which limit its use for therapeutic purpose. Alternatively, lentiviral vectors have been used to be safe and equally effective in producing iPS. Despite several cell types can be reprogramed, there is no information of which is the best cell type to be used in the generation of iPS. The umbilical cord is a reserve of multipotent mesenchymal stem cells and may present a greater reprogramming efficiency compared with fibroblasts in the generation of iPS. Here we describe the use of a single lentiviral vector composed by the combination of four transcription factors (Oct4, Sox2, Klf4, and c-Myc) for the generation of iPS cells using equine umbilical cord (UC) cells. Therefore, samples were collected from 5 equine UC at birth. The umbilical matrices were subjected to enzymatic digestion in a solution of 0.004% collagenase diluted in PBS, and the cells obtained by filtration were plated in plastic culture bottles with 5 mL of DMEM supplemented with 20% fetal calf serum, antibiotics, and antimycotics, followed by incubation at 37°C in a 100% humid atmosphere at 5% CO2 in air. When the cells reached 40% of confluence and a concentration of 105 cells, these cells were transduced with 50 μL Human Stemcca cre-excisable constitutive polycistronic (oskm) lentivirus (EMD Millipore Corp., Billerica, MA, USA) produced according manufacturer's protocol plus 8 ng mL–1 polybrene (hexadimethrine bromide, Sigma, St. Louis, MO, USA). The culture medium was renewed 12 h after incubation. Five days after transduction, cells were transferred to murine embryonic fibroblasts (MEF) feeder layer and cultured for 14 days in a specific medium for iPS. The morphologically similar colonies to the embryonic stem cells were visualised after two weeks of infection. When the clones were well established two mechanical and two enzymatic passages were performed. Cells were re-expanded under new MEFs and submitted to alkaline phosphatase activity detection (Leukocyte Alkaline Phosphatase Kit, Sigma) according to manufacturer's recommendations. Briefly, cell cultures were fixed, incubated with a mixture of alkaline naphthol AS-BI with fast red violet LB. Red labelling insoluble deposits indicated the sites of alkaline phosphatase activity. In all cultures tested (n = 10) the expression of alkaline phosphatase was detected. The cell culture samples will still be tested for gene expression of pluripotency factors. The combination of all factors in a single transcript was efficient for reprogramming cells from the umbilical cord and allowed the derivation of mesenchymal cells in equine iPS. The use of a single lentiviral reprogramming vector represents a powerful tool for the study of iPS technology and its possible therapeutic application.

Atherogenic dyslipidemia in patients with established coronary artery disease

BACKGROUND AND AIMS

Patients with stable coronary heart disease (CHD) and atherogenic dyslipidemia (AD) have a high-risk of recurrence and are those who derive most benefit from treatment with lipid-lowering agents. The aim of this study was to examine the prevalence of AD in patients with stable coronary heart disease and to investigate associated factors.

METHODS

Cross-sectional study involving 7823 subjects admitted for a coronary event between 6 months and 10 years previously. AD was considered to be the concurrent presence of low HDL-cholesterol (<1.03 mmol/L [40 mg/dL] in males, <1.29 mmol/L [50 mg/dL] in females) and elevated triglycerides (≥1.7 mmol/L [150 mg/dL]).

RESULTS

Mean age was 65.3 (10.1) years, 73.6% were males and 80.3% were receiving treatment with statins. Low HDL-cholesterol was observed in 26.3% of the participants, 39.7% had elevated triglyceride concentration and 13.0% had AD. The percentage of AD in patients with criteria for metabolic syndrome was 30.9%. Factors associated directly and independently with the presence of AD in the multivariate analysis were female sex, history of coronary syndrome without ST elevation or coronary revascularization, presence of atrial fibrillation, body mass index, LDL-cholesterol, systolic blood pressure and blood glucose levels, while age and glomerular filtration rate were significantly and inversely associated with AD.

CONCLUSION

A significant proportion of patients with coronary disease could benefit from interventions aimed at increasing HDL-cholesterol and reducing triglycerides.

[Prevalence of metabolic syndrome in patients with stable coronary disease: therapeutic objectives and utilization of cardiovascular drugs]

OBJECTIVE

The achievement of the therapeutic objectives in patients with ischemic heart disease and metabolic syndrome is unknown. This study has aimed to evaluate whether the prevalence of risk factors, the prescription rate of evidence-based cardiovascular therapies and the attainment of therapeutic goals differ in coronary patients with and without the metabolic syndrome (MS).

METHODS

A multicenter, cross-sectional study carried out with the participation of 7,600 patients with stable coronary heart disease (mean age 65.3 years, 82% males, 37.7% with MS) attended in primary care. Data on drug prescription and goal attainment were extracted from clinical records. MS was defined according to the National Cholesterol Education Program (NCEP) criteria.

RESULTS

Patients with MS had a higher prevalence of cardiovascular risk factors and cardiovascular disease. They also had a higher prescription rate of blood-pressure lowering drugs, statins and antidiabetic agents, without differences in the rate of use of antithrombotics and beta-blockers. After adjusting for cardiovascular risk factors and co-morbidity, only fibrates and angiotensin II receptor blockers were used more frequently in MS patients. A lower percentage of subjects with MS achieved therapeutic goals of LDL cholesterol (23.4% vs 27.7%, P<.001), blood pressure (29.1% vs 52.2%, P<.001) and, in diabetics, of glycated hemoglobin (54.7% vs 75.9%, P<.001).

CONCLUSION

Patients with stable coronary disease and MS do not reach therapeutic objectives as frequently as those without MS, in spite of receiving a higher amount of cardiovascular drugs.

[Delayed primary anastomosis in esophageal atresia without fistula. 10 years' experience]

From 1984 until 1994 there were 7 cases of newborn with esophageal atresia without fistulae, five of which were treated through primary anastomosis and two of these presented exceptional long gaps. This article is an analysis of these 7 newborns, their post-operative complications and the therapeutics used. Two deaths occurred due to associated serious cardiac pathologies, which made delayed primary anastomosis impossible, and one sudden death four months after the esophageal anastomosis. Three of these cases present a good stature-weight progression and one remains slightly under the 5 percentile. Considering our results, the delayed primary anastomosis in the esophageal atresias with long gap, in spite of the post-operative complications, shall continue to be the author's choice.

[Epidemiologic study of adult bronchial asthma in a Benin hospital environment]

This work is a contribution to the epidemiological study of bronchial asthma in adults in a hospital environment at Cotonou. It is a question of the necessity of admission to hospital of clinical cases. The study has emphasized the following points: Separation according to age has shown that 52% of patients are less than 35 years old, young subjects are in this group. The two sexes are equally involved, with a sex ratio of 1. The different socio-professional groups involved have shown a predominance of those without profession. The main allergic factors identified by questioning are dominated by housedust, which suggests, failing allergological tests, that the role of mites is probably preponderant. There does not seem to be any particular influence of meteorological factors (rain or dryness) on the frequency of crises. Finally, it should be emphasized that technical difficulties make it very difficult to study asthma in Benin.

[Asthma and allergens in Benin (Western Africa). Preliminary results with the in vitro RAST technic]

The present work studied the importance of allergy in a population of 41 asthmatics in Benin, using specific IgE measurement by RAST. Specific serum IgE to different allergens has been found in 80% of all cases. Reactions were frequently positive when grass pollens were used and more than half of the patients were sensitive to mites. Standard commercial reagents were used for the tests. Africa-specific allergens were not used in the study, but it is probable that in Western Africa the same allergens as in Europe man be found, or at least those with common allergenic determinants.