Detection ofHelicobacter pyloriAntigen in Stool by Enzyme Immunoassay

Abstract

Invasive techniques for diagnosis of Helicobacter pylori (H. pylori) infection require an endoscopic examination which is expensive and inconvenient and may cause complications. Stool cultures for H. pylori or a direct detection of H. pylori antigen in stools by PCR are expensive, tedious, and have a low sensitivity. We recently used an enzyme immunoassay (EIA) to detect H. pylori antigen in stool specimens. A total of 41 patients were seen at Inha University Hospital, Inchon, Korea between September and October 1998. There were 26 men and 15 women who had an average age of 37.6 years which ranged from 5 to 71 years in the present study. All of these patients came to the hospital complaining of an upper abdominal discomfort and were subjected to endoscopy and biopsies. Fifteen had a gastric ulcer, 13 had a duodenal ulcer, 1 had an early gastric cancer, and there were 12 chronic gastritis patients as shown by endoscopy. The biopsy specimens were examined by histology, CLO test, and cultures and these results were used as gold standards. Stool specimens were tested for the H. pylori antigen by EIA. A dual wavelength cut-off of 0.100 that was recommended by the manufacturer gave a good performance (87.1% sensitivity, 100% specificity, 100% positive predictive value, 71.4% negative predictive value, and a 90.2% efficiency). But the adjusted cut-off value using the receiver operating characteristic curve improved the performance of the test (using the cut-off value of 0.024, the sensitivity, specificity, PPV, NPV, and efficiency were 100%, 90.0%, 96.9%, 100%, and 97.6% respectively). Re-evaluation of the cut-off value may be needed for Korean patients. This technique is non-invasive, rapid, easy-to-use, and shows good performance characteristics for diagnosis of H. pylori infections. Therefore, this technique may be a substitute for gastric endoscopy especially in children and some patients who are unable to tolerate an endoscopic examination and it may be substituted for a serologic test in epidemiological research.

Essential Role of the E3 Ubiquitin Ligase NOPPERABO1 in Schizogenous Intercellular Space Formation in the Liverwort Marchantia polymorpha

“…In Arabidopsis, cell separation during floral organ abscission after pollination and lateral organ emergence are regulated by the peptide INFLORESCENCE DEFICIENT IN ABSCISSION, which signals through the Leu-rich repeat receptor-like kinases HAESA and HAESA-LIKE2, and the process is involved in the regulation of cell wall remodeling (Stenvik et al, 2008;Kumpf et al, 2013). Increasing evidence implicates the involvement of PUB-ARM proteins in various plant receptor-like kinase signaling pathways, and the ARM domains mediate binding to the kinase domains (Gu et al, 1998;Kim et al, 2003;Samuel et al, 2006Samuel et al, , 2008Mbengue et al, 2010;Lu et al, 2011). For example, the PUB-ARM proteins PUB12 and PUB13 attenuate the activity of the Arabidopsis flagellin-sensing receptor 2 by ubiquitination and subsequent degradation (Lu et al, 2011).…”

Quantitative Correlation of Helicobacter pylori Stool Antigen (HpSA) Test with the Severity of H. pylori-Related Gastritis

“…In their patient group 6 of 63 (9.5%) patients were H. pylori positive. On the other hand, in another patient group where 31 of 41 (75.6%) patients were H. pylori positive, 87.1% sensitivity and 100% specificity were detected according to the manufacturer's cut-off value, and 100% sensitivity and 90% specificity were detected according to the calculated cut-off value of 0.024 by ROC curve analysis (Kim et al 2002). These two studies may indicate that in low H. pylori prevalent populations the cut-off values of HpSA test are higher whereas in high H. pylori prevalent populations the cut-off values are lower which is in accordance with our results.…”

“…In our study, the sensitivity of the HpSA test was found and specificity. In these studies, the best cut-off values calculated by ROC curve analysis were from OD; 0.024 to 0.3 (Ohkura et al 2000;Leodolter et al 2001;Kim et al 2002;Kato et al 2003;Syam et al 2005). In our dyspeptic patients, the best cut-off value calculated by ROC curve analysis was 0.048 and by using this cut-off value, the sensitivity of the test increased from 51.1% to 92% without decreasing the specificity of the test.…”

“…To overcome this problem, in different studies, it was reported that by calculating the cut-off values of HpSA test by receiver operator characteristics (ROC) curve analysis, the sensitivity and specificity of HpSA test increases (Leodolter et al 2001;Kim et al 2002;Kato et al 2003;Syam et al 2005). Makristatis et al (2000) also stressed the importance of local test validation especially in post treatment follow-up.…”

Bio- and chemo-catalytic preparations of chiral epoxides

“…Microbial epoxide hydrolases can be produced in large amounts by using recombinant DNA technology [50,51]. Most of synthetic applications of epoxide hydrolases have been achieved by using bacterial enzymes or fungal enzymes [52,53].…”