Development of antibody-based microarray assay for quantitative detection of aflatoxin B1

Aflatoxin B1 [AFB1] is a toxic metabolite produced by Aspergillus species that contaminates a wide range of agricultural products. This study was designed to develop a rapid and highly sensitive immunoassay method in microarray format for quantitative detection of AFB1 to evaluate the potential of microarray platform for high-throughput screening, which can be beneficial in food and feed industry. Following successful optimization, using an indirect competitive immunoassay in dot blot format, AFB1-bovine serum albumin [AFB1-BSA] conjugate was contact-printed onto 16 isolated subarrays on multi-pad nitrocellulose coated slides; subsequently used in competitive binding assays. Using the aforementioned assay, AFB1 was determined from 15 pg/g to 3.04 ng/g working range with detection limit [LOD] of 1 pg/g. To evaluate assay performance in real food matrices, the authors spiked wheat samples with different concentration of AFB1. After extraction, working ranges of 0.11-4.15 ng/g with detection limit of 30pg/g was determined. Good recoveries [94 +/- 9%] were obtained, demonstrating accurate detection of AFB1 concentrations in wheat samples. Assay procedure completed in 3 hours. The results indicated that the proposed developed assay in microarray format could be used for rapid and sensitive detection of AFB1in wheat samples

Histopathologic changes in patients with H. pylori positive chronic gastritis, before and after treatment

To evaluate histopathologic changes, between pre and post anti-Helicobacter pylori treatment using three different modalities, 108 patients with duodenal ulcer and H. pylori positive chronic gastritis were selected. Biopsies for histopathology and rapid urease test were taken from antrum and body and fundus regions, before and after treatment. Histopathologic evaluation was based on updated Sydney System. H. pylori in 45 of 108 patients [41.7%] became histologically eradicated, however rapid urease test was negative in 83 patients [76.8%]. The grade of gastritis and mean eosinophilic infiltration count were significantly decreased on post treatment biopsies in both eradicated and non eradicated patients [P value = 0.000,0.005 and 0.000,0.032 respectively]. Active inflammation was resolved in both eradicated and non eradicated groups [P Value = 0.000 and 0.002 respectively]. Density of H. pylori was significantly decreased in non eradicated group. Changes in atrophy and intestinal metaplasia were not statistically significant due to inadequate patients number, suffering from atrophy and/or intestinal metaplasia. Eradication of H. pylori is accompanied by significant histopathologic improvement. To evaluate reversibility of atrophy and intestinal metaplasia, larger study groups is needed. In comparison with histopathology, rapid urease test has low sensitivity