Papers by Salman Siddiqui
Journal of Allergy and Clinical Immunology, 2016
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European Respiratory Journal, Sep 1, 2011
Background: Lung function decline over time is an important variable for patients with severe/dif... more Background: Lung function decline over time is an important variable for patients with severe/difficult asthma and it is unclear how granulocytic cell counts in sputum are associated with this variable as few longitudinal studies include both biomarkers. Aims and objectives: To analyse lung decline, post bronchodilator FEV1 was recorded over time in order to determine the best fitting mixed effect model to determine the role of granulocytes. Methods: Data was collected form the Glenfield Hospital Severe asthma clinic, the mean duration of follow up and number of visits were 6 years and 2.7/years. A mixed effect model was applied to the data. Using individual patient mean and standard deviation over time, a statistical mixture/cluster analysis was implemented. Results: For the best fitting mixed effects model FEV1 decline was -25.7ml/year, p=0.0001. The significant independent fixed effects included exacerbations, age of onset, log eosinophils (p<0.001). Three clusters were found in the log eosinophil cluster analysis. Cluster 1 described a low grade eosinophilic group. Cluster 2, a hyper eosinophilic group and cluster 3, a neutrophilic/non-eosinophilic group. The clusters differed in their frequency of exacerbation/decline. Conclusions: Eosinophils were found to be a significant predictor for FEV1 decline. Clustering eosinophil variables found that patients are either consistently eosinophilic over time, consistently non eosinophilic over time or have a large amount of eosinophilic variation.
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European Respiratory Journal, 2015
Background: Patients with asthma experiencing recurrent infective exacerbations are started on pr... more Background: Patients with asthma experiencing recurrent infective exacerbations are started on prophylactic antibiotics but this phenotype of asthma is not well defined. We sought to; a) characterise the population of patients with recurrent infections in the Leicester difficult asthma clinic (DAC) and develop a 9standard9 for case definition and b) assess whether prophylactic antibiotic use in this population leads to a reduction in exacerbation frequency. Methods: We reviewed the Leicester DAC letters from the last two calendar years to identify patients with both a clinician diagnosis of asthma and ≥2 infections in the preceding year. 87 asthmatic patients with recurrent infections were identified. We evaluated the clinical characteristics, antibiotic use, physiology, imaging, immunoglobulins and pneumococcal serotype meta-data of this population. Results: This asthma population was predominantly female (69%), obese (mean BMI:31.9), eosinophilic (mean:0.27x10 9 ) with early onset asthma (mean:21.7 years) and recurrent infections (mean:4.1 in the preceding year). 62 patients were on prophylactic antibiotic therapy with 35.5% having a reduction in infective asthma exacerbation frequency with this treatment. CT evidence of bronchiectasis was present in 28.7% and bronchial dilation in 21.8%. 20.7% received pneumovax for low pneumococcal serovars and 83.3% of these patients had a positive response. Conclusion: The use of prophylactic antibiotics in patients with asthma with recurrent infections leads to a reduction in exacerbation frequency in some patients but not all. Further immunpathological studies are required to establish the mechanism of infections in this asthma phenotype.
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The Himalayan region is considered to be very sensitive to climate change due to the high variati... more The Himalayan region is considered to be very sensitive to climate change due to the high variation in altitudes. Changes in cloud cover and rainfall, particularly over land; melting of ice caps and glaciers and reduced snow cover are some of the prominent threats due to rise in temperature. The significant effect of climatic variability in major rivers and their tributaries has already been observed. As a result, rivers and tributaries, catchments, and watersheds are at risk from increased flooding, landslides, soil erosion, drought and more intense rain during the monsoon. Using watersheds as organizing units for planning and implementation of natural resources management is an approach being followed worldwide because large regions can be divided along topographic lines that transcend administrative boundaries and the status and trends analysis can be done on the basis of entire natural systems in concert with social conditions. The communities within the watersheds can also bett...
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Journal of Allergy and Clinical Immunology, 2014
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Current Opinion in Pulmonary Medicine, 2011
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Thorax, 2009
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Respiratory Research, 2010
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Respiration, 2014
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Microelectronics Reliability, 1995
Pergamon 00262714 (93) E00174 Microelectron. Reliab., Vol. 35, No. I, pp. 109 I II. 1995 Copyrigh... more Pergamon 00262714 (93) E00174 Microelectron. Reliab., Vol. 35, No. I, pp. 109 I II. 1995 Copyright c, 1994 Elsevier Science Ltd Printed in Great Britain. All rights reserved 00262714 95 7.00+.00 TECHNICAL NOTE A NEW INCREASING FAILURE RATE MODEL FOR LIFE TIME DATA ...
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The Journal of Immunology, 2010
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Journal of Allergy and Clinical Immunology, 2014
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Journal of Allergy and Clinical Immunology, 2009
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Journal of Allergy and Clinical Immunology, 2007
Increased vascularity and expression of vascular endothelial growth factor (VEGF) are recognized ... more Increased vascularity and expression of vascular endothelial growth factor (VEGF) are recognized features of the asthmatic airway. The association of vascular remodeling with airway hyperresponsiveness (AHR) is unclear. To assess vascular remodeling and sputum VEGF concentration in subjects with asthma, subjects with nonasthmatic eosinophilic bronchitis (EB), and healthy controls. In cohort 1, 19 patients with asthma (Global Initiative for Asthma [GINA] 1-2, n = 9; GINA 3-5, n = 10), 10 patients with EB, and 11 healthy matched controls were recruited. Expression of the endothelial marker EN4 was assessed in bronchial biopsy samples. Vessels were counted using the validated mean Chalkley count by a blind observer. For cohort 2, a second independent cohort of 31 patients with asthma (GINA 1-2, n = 11; GINA 3-5, n = 20), 14 patients with EB, and 15 matched controls was recruited. Induced sputum supernatant VEGF was measured by ELISA. The mean chalkley count was significantly greater in GINA 3-5 asthma (5.2 [0.4]) and EB (4.8 [0.3]) compared with controls (3.5 [0.5]) and demonstrated a significant inverse correlation with the postbronchodilator FEV(1)% predicted in patients with asthma (R(2) = 0.28; P = .02). Sputum VEGF concentration was also increased in GINA 3-5 asthma (2365 [1361-4110] pg/g) and EB (4699 [2818-7834] pg/g) compared with controls (1094 [676-1774] pg/g) and was inversely related to postbronchodilator FEV(1)% predicted in asthma (R(2) = 0.2; P = .01). Vascular remodeling is a feature of asthma, and EB and is inversely associated with the postbronchodilator FEV(1) in asthma, suggesting that vascular remodeling is associated with airflow obstruction but not AHR. Vascular remodeling is dissociated from AHR in asthma and associated with airflow limitation.
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Journal of Allergy and Clinical Immunology, 2010
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Clinical & Experimental Allergy, 2013
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CHEST Journal, 2010
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Papers by Salman Siddiqui