يعرض 1 - 10 نتائج من 11 نتيجة بحث عن '"Eifan, A"', وقت الاستعلام: 0.76s تنقيح النتائج
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    المساهمون: Sharif, Hanisah, Acharya, Swati, Dhondalay, Gopal Krishna R., Varricchi, Gilda, Krasner-Macleod, Shoshanna, Laisuan, Wannada, Switzer, Amy, Lenormand, Madison, Kashe, Elena, Parkin, Rebecca V., Zhang, Yi, Koc, Merve, Fedina, Oleksandra, Vilà-Nadal, Gemma, Marone, Gianni, Eifan, Aarif, Scadding, Guy W., Fear, David J., Nadeau, Kari C., Durham, Stephen R., Shamji, Mohamed H.

    الوصف: Background: Allergen-specific immunotherapy (AIT) is a disease-modifying treatment that induces long-term T cell tolerance. Objective: To evaluate the role of circulating CXCR5+ PD-1+. T follicular helper (cTFH) and T. follicular regulatory (TFR) cells following grass pollen subcutaneous (SCIT) and sublingual (SLIT) immunotherapy and the accompanying changes in their chromatin landscape. Methods: Phenotype and function of cTFH cells were initially evaluated in grass pollen-allergics (GPA, n= 28) and non-atopic controls (NAC, n=13) by mathematical algorithms developed to manage high-dimensional data and cell culture, respectively. cTFH and TFR cells were further enumerated in NAC (n=12), GPA (n=14), SCIT (n=10) and SLIT (n=8)-treated groups. Chromatin accessibility in cTFH and TFR cells was assessed by ATAC-seq to investigate epigenetic mechanisms underlying the differences between NAC, GPA, SCIT and SLIT. Results: cTFH cells were shown to be distinct from TH2 and TH2A cell subsets, capable of secreting. IL-4 and IL-21. Both cytokines synergistically promoted B cell class switching to IgE and plasma cell differentiation. Grass pollen allergen induced cTFH cell proliferation in GPA but not in NAC (P

  2. 2

    المصدر: Scientific Reports
    Scientific Reports, Vol 11, Iss 1, Pp 1-12 (2021)

    الوصف: The routine evaluation of water environments is necessary to manage enteric virus-mediated fecal contamination and the possible emergence of novel variants. Here, we detected human rotavirus A (HRVA) circulating in two wastewater treatment plants, two lakes, irrigation water and a wastewater landfill located in Riyadh. VP7-derived surface protein sequences were assessed by phylogenetic analyses and inspection of thermotolerance-mediated secondary structure and seasonal variation. HRVA was most prevalent at An-Nazim wastewater landfill (AN-WWLF; 63.89%). Phylogenetic analyzes revealed the predominance of HRVA G2 lineage for the first time in Saudi Arabia. Moreover, a single HRVA sequence (2B64I-ANLF3/2018) was recovered at 45 °C from AN-WWLF; secondary structure prediction indicated that this sequence was thermotolerant with a high hydrophobicity, an absence of Ramachandran outliers, and a higher content of proline patches on the protein surface. Varied relationships were significantly observed between sampling areas influenced by temperature ranges (p p = 0.01). Our study extends the knowledge of currently circulating HRVA genotypes, and indicates the probable emergence of thermotolerant strains and seasonally mediated HRVA prevalence.

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    المصدر: Journal of virological methods. 295

    الوصف: Routine wastewater treatment plants (WWTPs) effluents monitoring is essential because of enteric viruses' low infectious dose beyond molecular detectability. In current study methods for concentration and extraction, inter-method compatibility and recovery efficiency of spiked human adenovirus (HAdV) and human rotavirus A (RVA) were evaluated. For virus concentration, polyethylene glycol precipitation (PEG), charged membrane-based adsorption/elution (CMAE), and glass wool-based concentration (GW) methods were used. Nucleic acid was extracted by PowerViral™ Environmental RNA/DNA Isolation (POW), ZymoBIOMICS™ RNA extraction (ZYMO) and Wizard® Genomic DNA Purification (WGDP) and samples were analyzed by Real-Time PCR. CMAE method yielded significantly higher concentrations for both ARQ (Armored-RNA Quant) and RVA compared to PEG (P = 0.001 and 0.003) and GW (P

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    المصدر: Saudi Journal of Biological Sciences, Vol 28, Iss 6, Pp 3325-3332 (2021)
    Saudi Journal of Biological Sciences

    الوصف: The sequences of SARS-CoV-2 spike (S) from Saudi Arabia along with SARS-CoV and bat SARS-like CoVs were obtained. Positive selection analysis and secondary structure investigation of spike sequences were performed. Adaptive molecular evolution was observed in SARS-CoV-2 displayed by positive selection pressure at N-terminal domain (NTD; codons 41, 163, 174 and 218), Receptor binding domain (RBD; codons 378 and 404) and S1/S2 Cleavage site (codon 690). Furthermore, the spike protein secondary structure depicted by the homo-trimer structure showed a high similarity between Saudi SARS-CoV-2 isolate and the parental strain (bat SL-COVZC45). Despite the high similarity depicted in the spike sequence model alignment, it displayed a significant difference when each chain was treated solely owing to 7 motif differences in the three composing chains. In addition, SARS-CoV-2 S trimer model uncovered the presence of N-acetyl glucosamine ligands. Eventually, 3C-like proteinase cleavage site was observed in S2 domain could be used as a site for drug discovery. Genetics and molecular evolutionary facts are useful for assessment of evolution, host adaptation and epidemic patterns ultimately helpful for adaptation of control strategies.

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    المساهمون: Medical Research Council (MRC), Shamji, Mohamed H., Kappen, Jasper, Abubakar-Waziri, Hisham, Zhang, Jinjin, Steveling, Esther, Watchman, Shelley, Kouser, Lubna, Eifan, Aarif, Switzer, Amy, Varricchi, Gilda, Marone, Gianni, Couto-Francisco, Natália C., Calderon, Moise, Durham, Stephen R.

    الوصف: BACKGROUND: Grass pollen subcutaneous immunotherapy (SCIT) is associated with induction of serum IgG4-associated inhibitory antibodies that prevent IgE-facilitated allergen binding to B cells. OBJECTIVE: To determine whether SCIT induces nasal allergen-specific IgG4 antibodies with inhibitory activity that correlate closely with clinical response. METHODS: In a cross-sectional, controlled study, nasal fluid and sera were collected during the grass pollen season from 10 SCIT-treated patients, 13 untreated allergics (SAR) and 12 non-atopic controls (NA). Nasal and serum IgE and IgG4 to Phleum pratense (Phl p) components were measured by ISAC microarray. Inhibitory activity was measured by IgE-FAB assay. IL-10+Breg cells were quantified in peripheral blood by flow cytometry. RESULTS: Nasal and serum Phl p1 and Phl p5-specific IgE levels were elevated in SAR compared to NA (all, P < .001) and SCIT group. Nasal IgG4 levels were increased in SCIT compared to SAR group (P < .001) during the pollen season compared to out of season. IgG-associated inhibitory activity in nasal fluid and serum was significantly increased in SCIT compared to SAR group (both, P < .001). The magnitude of the inhibitory activity was 96% in the nasal fluid compared to 66% in serum and was reversed following depletion of IgG in nasal fluid (P = .03) and serum (P = .002). Both nasal fluid (r = -0.67, P = .0011) and serum (r = -0.59, P = .0097) blocking activity correlated global symptom improvement. IL-10+Breg cells were increased in season compared to out of season in SCIT group (P < .01). CONCLUSION: For the first time, we show that nasal IgG4-associated inhibitory activity correlate closely with the clinical response to allergen immunotherapy in allergic rhinitis with/without asthma.

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    المصدر: Clinical and experimental allergy : journal of the British Society for Allergy and Clinical ImmunologyREFERENCES. 51(2)

    الوصف: BACKGROUND Local tissue eosinophilia and Th2 cytokines are characteristic features of seasonal allergic rhinitis. Airway remodelling is a feature of asthma whereas evidence for remodelling in allergic rhinitis (AR) is conflicting. OBJECTIVE By use of a novel human repetitive nasal allergen challenge (RAC) model, we evaluated the relationship between allergic inflammation and features of remodelling in AR. METHODS Twelve patients with moderate-severe AR underwent 5 alternate day challenges with diluent which after 4 weeks were followed by 5 alternate day challenges with grass pollen extract. Nasal symptoms, Th1/Th2 cytokines in nasal secretion and serum were evaluated. Nasal biopsies were taken 24 hours after the 1st and 5th challenges with diluent and with allergen. Sixteen healthy controls underwent a single challenge with diluent and with allergen. Using immunohistochemistry, epithelial and submucosal inflammatory cells and remodelling markers were evaluated by computed image analysis. RESULTS There was an increase in early and late-phase symptoms after every allergen challenge compared to diluent (both P

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    المؤلفون: Stephen R. Durham, Aarif O. Eifan

    المصدر: Clinical & Experimental Allergy. 46:1139-1151

    الوصف: Rhinitis is a heterogeneous condition that has been associated with inflammatory responses as in allergic rhinitis but can also occur in the absence of inflammation such as in so-called idiopathic (previously 'vasomotor') rhinitis. Allergic rhinitis affects approximately one in four of the population of westernized countries and is characterized by typical symptoms of nasal itching, sneezing, watery discharge and congestion. The intention of this review is to illustrate key concepts of the pathogenesis of rhinitis. Imbalance in innate and adaptive immunity together with environmental factors is likely to play major roles. In allergic rhinitis, initial allergen exposure and sensitization involves antigen-presenting cells, T and B lymphocytes and results in the generation of allergen-specific T cells and allergen-specific IgE antibodies. On re-exposure to relevant allergens, cross-linking of IgE on mast cells results in the release of mediators of hypersensitivity such as histamine and immediate nasal symptoms. Within hours, there is an infiltration by inflammatory cells, particularly Th2 T lymphocytes, eosinophils and basophils into nasal mucosal tissue that results in the late-phase allergic response. Evidence for nasal priming and whether or not remodelling may be a feature of allergic rhinitis will be reviewed. The occurrence of so-called local allergic rhinitis in the absence of systemic IgE will be discussed. Non-allergic (non-IgE-mediated) rhinitis will be considered in the context of inflammatory and non-inflammatory disorders.

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    المساهمون: Cox, L

    المصدر: Current Treatment Options in Allergy

    الوصف: Rationale Subcutaneous and sublingual immunotherapy are effective for allergic rhinitis. An important question is whether allergen immunotherapy provides a sustained clinical effect after treatment cessation. In view of potential side effects, cost and the necessary patient commitment, long-term benefit is an important consideration for the recommendation of immunotherapy over standard pharmacotherapy. Purpose of review In this review, we analyse the existing evidence for long-term effects of both routes of administration in the context of double-blind, placebo-controlled, randomised clinical trials that included a follow-up phase of at least 1 year after treatment cessation. Recent findings Overall, evidence suggests that 3 years of either subcutaneous or sublingual immunotherapy result in clinical benefit and immunological changes consistent with allergen-specific tolerance sustained for at least 2–3 years after treatment cessation. Summary The data presented here support recommendations in international guidelines that both routes of administration should be continued for a minimum of 3 years. Gaps in the evidence remain regarding the long-term efficacy of immunotherapy for perennial rhinitis and studies performed in children.

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    المصدر: Saudi Journal of Biological Sciences
    Saudi Journal of Biological Sciences, Vol 24, Iss 7, Pp 1631-1638 (2017)

    الوصف: Since the initial emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012, a high incidence rate has been observed in Saudi Arabia. This suggests that the country is at continuous risk. The epidemic level of MERS-CoV infection was examined in Saudi Arabia by the Susceptible-Infectious-Recovered (SIR) model using a Bayesian approach for estimation of time dependent reproduction number (R) across a two-year interval (May, 2013-May, 2015) in five defined clusters, followed by sensitivity analysis of the most significant clusters. Significant MERS-CoV peaks were detected in the period between March and May of each year. Moreover, MERS-CoV infection was highlighted in western (40.8%) and central (31.9%) regions, followed by eastern region (20%). The temporal-based Bayesian approach indicated a sub-critical epidemic in all regions in the baseline scenario (R: 0.85-0.97). However, R potential limit was exceeded in the sensitivity analysis scenario in only central and western regions (R: 1.08-1.12) that denoted epidemic level in those regions. The impact of sporadic cases was found relatively insignificant and pinpointed to the lack of zoonotic influence on MERS-CoV transmission dynamics. The results of current study would be helpful for evaluation of future progression of MERS-CoV infections, better understanding and control interventions.

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    المصدر: BioMed Research International, Vol 2017 (2017)
    BioMed Research International

    الوصف: Respiratory infections are caused by an array of viruses, and limited information is available about viral coexistence, comparative symptoms, and the burden of illness. This retrospective cohort study aimed to determine the etiological agents responsible for respiratory tract infections by Anyplex II RV16 detection kit (RV16, Seegene), involving 2266 pediatric patients with respiratory infections admitted to the Department of Pediatrics at King Abdul-Aziz Medical City, Ministry of National Guard, Riyadh, from July 2014 to June 2015. The most frequent respiratory infections were recorded in the 1 to 5 year age group (44.7%). Rhinovirus (32.5%), Adenovirus (16.9%), and Respiratory syncytial virus (RSV) B (10.4%) were most common. In single viral infections, Rhinovirus (41.2%), Metapneumovirus (15.3%), and Bocavirus (13.7%) were most frequent. In multiple viral infections, Rhinovirus (36.7%), Adenovirus (35.2%), Bocavirus (11.2), RSV B (7.8%), and RSV A (6.7%) were most frequent. No significant difference was observed in clinical presentations; however, rhinorrhea and hypodynamia were significantly associated with viral respiratory infections. Most respiratory viral pathogens peaked during December, January, March, and April. Rhinovirus, Adenovirus, and Bocavirus circulations were detected throughout the year. Winter peaks were recorded for Rhinovirus, RSV B, Adenovirus, and RSV A, whereas the Metapneumovirus, and the Bocavirus peaked in March and April. These findings enhance understanding of viral etiology and distribution to improve respiratory infection management and treatment.

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