Pylori Assay Research Articles

Two clerodane diterpenes isolated from Polyalthia longifolia leaves: comparative structural features, anti-histaminic and anti-Helicobacter pylori activities

Phytochemical studies of methylene chloride soluble fraction from the 70% aqueous-alcoholic extract of Polyalthia longifolia (leaves) resulted in the isolation of two known clerodane diterpenes, namely: 16α-hydroxycleroda-3,13(14)-dien-16,15-olide (1) and (4→2)-abeo-16-hydroxy-cleroda-2,13(14)-dien-15,16-olide-3-al (2). The isolated compounds were evaluated for their anti-histaminic and anti-Helicobacter pylori activities. Compound 1 was more potent than 2 with IC50 29.7 μg/mL and 189.2 μg/mL in the anti-histaminic assay and MIC equals to 31.25 μg/mL and 125 μg/mL in the anti-H. pylori assay, as compared with diclofenac (IC50 = 17.9 μg/mL) and clarithromycin (MIC = 1.95 μg/mL), respectively. The differences in their structures, as well as their activity results, indicated important characteristic features necessary for activity. It was suggested that the decalin moiety in 1 was important for both activities. On the other hand, the (4→2)-abeo migration in 2 reduced both activities. The potent activities of 1 suggest its potential application as an anti-histaminic and antimicrobial agent.

Molecular detection of Helicobacter pylori and clarithromycin resistance in gastric biopsies: a prospective evaluation of RIDA®GENE Helicobacter pylori assay

ABSTRACT Background: Empirical treatment of Helicobacter pylori (HP) depends on the local prevalence of clarithromycin resistance but data are lacking and culturing of HP is time-consuming. We evaluated RIDA®GENE Helicobacter pylori assay (r-biopharm), a quantitative PCR assay for detecting HP and clarithromycin resistance mutations in gastric biopsies. Material/methods: Gastric biopsies were obtained from each of 436 consecutive patients referred for gastroscopic investigation and results of qPCR were compared to culture and immunohistochemical staining (IHCS). Results: Of 436 samples, 47 were positive for HP by PCR (11%), 42 by culture (9.7%) and 44 by IHCS (10%). Compared to culture, sensitivity and specificity of the qPCR were 100% and 99%, respectively, and 96% and 99% compared to IHCS. The sensitivity and specificity for clarithromycin resistance detection were 92% and 97%, respectively. Conclusions: RIDA®GENE Helicobacter pylori assay reliably and rapidly detects HP and its resistance to clarithromycin in human gastric biopsies.

Anti-Helicobacter pylori effect of the antioxidant extract from <em>Baccharis trimera</em> Less. (DC)

<p>One of the main risk factors for the development of stomach ulcers and cancer is infection with Helicobacter pylori bacteria, which is accompanied by considerable oxidative stress. Therefore, the aim of the present study was to assess the anti-Helicobacter pylori activity of B. trimera hydroalcoholic extract (HE) and aqueous (AqF), hexanic (HxF), and acetonitrile/chloroform (ACF) fractions, as well as their oxidant potentials.</p><p>A preliminary phytochemical screening was carried out. Anti-Helicobacter pylori activity was assessed using a microdilution assay. After exposure to the investigated samples, the bacterial morphology was analysed under a scanning electron microscope (SEM). The antioxidant activity was evaluated in hydrogen peroxide (H 2 O 2 ), superoxide anion (O 2 •- ), hypochlorous acid (HOCl), hydroxyl radical (HO • ) and nitric oxide (NO • ) assays.</p><p>The highest concentration of polyphenols was found in HE, the highest concentration of flavonoids was found in ACF, and of tannins was found in AqF. In the anti-H. pylori assay, the MIC 90 was 512 µg/mL for HE and 1024 µg/mL for ACF, which was bactericidal. The SEM showed morphological alterations such as cell lysis in the tested samples. In the O 2 •- inhibition assay, the EC 50 of AqF was 5.85 ± 0.86. In the HOCl, HO • radical, NO • and H 2 O 2 scavenging assays, the best results were in ACF, with an EC 50 of 15.50 ± 0.80, 2.90 ± 0.48, 132.13 ± 7.38 and 66.70 ± 2.30 µg/mL, respectively. The analyses indicate that compounds present in B. trimera, especially in HE and ACF, are promising candidates for the prevention and treatment of diseases caused by H. pylori.</p>

Performance evaluation of a rapid whole-blood immunoassay for the detection of IgG antibodies against Helicobacter pylori in daily clinical practice.

BackgroundA growing number of rapid Helicobacter pylori antibody tests are commercially available now, however, some of these tests are often used without sufficient evaluation. The aim of this study was to evaluate the performance of a commercially available rapid whole-blood immunoassay (gabControl®H. pylori; gabmed GmbH, Köln, Germany), for the qualitative detection of IgG antibodies against H. pylori with the 13C-urea breath test (13C-UBT) serving as a reference method.MethodsA total of 108 consecutive outpatients, who were referred for 13C-UBT by general practitioners and specialists, were also tested for H. pylori infection by the gabControl®H. pylori immunoassay. The clinical performance of this rapid whole-blood test was evaluated by determining the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) compared to the 13C-UBT. The agreement between the two tests was calculated using Cohen’s Kappa (κ) with 95 % confidence intervals (CI).ResultsThe agreement between the gabControl®H. pylori assay and the 13C-UBT was 0.62 [95 % confidence intervals (CIs) 0.47–0.76; P < 0.001]. With the 13C-UBT serving as the non-invasive gold standard method of H. pylori diagnosis, the gabControl®H. pylori assay demonstrated a sensitivity and specificity of 91.4 and 76.7 %, respectively, with a PPV of 65.3 % and a NPV of 94.9 %. Seventeen (15.7 %) individuals with a positive H. pylori anamnesis showed a negative 13C-UBT and were typed positive by the gabControl®H. pylori assay. Of these, 13 (76.5 %) and 3 individuals (17.6 %) had completed one and two eradication therapies, respectively.ConclusionsThe gabControl®H. pylori immunoassay is a rapid and easy to use first line screening tool for H. pylori IgG antibody detection in daily clinical practice. However, this assay should not be used for confirmation of the successful H. pylori eradication after antibiotic treatment.

Do decision-analytic models identify cost-effective treatments? A retrospective look at helicobacter pylori eradication.

Pharmacoeconomic models of Helicobacter (H) pylori eradication have been frequently cited but never validated. Examine retrospectively whether H pylori pharmacoeconomic models direct decision makers to cost-effective therapeutic choices. We first replicated and then validated 2 models, replacing model assumptions with empirical data from a multipayer claims database. Database subjects were 435 commercially insured U.S. patients treated with bismuthmetronidazole- tetracycline (BMT), proton pump inhibitor (PPI)-clarithromycin, or PPI-amoxicillin. Patients met >1 clinical requirement (ulcer disease, gastritis/duodenitis, stomach function disorder, abdominal pain, H pylori infection, endoscopy, or H pylori assay). Sensitivity analyses included only patients with ulcer diagnosis or gastrointestinal specialist care. Outcome measures were: (1) rates of eradication retreatment; (2) use of office visits, hospitalizations, endoscopies, and antisecretory medication; and (3) cost per effectively treated (nonretreated) patient. Model results overstated the cost-effectiveness of PPI-clarithromycin and underestimated the cost-effectiveness of BMT. Prior to empirical adjustment, costs per effectively treated patient were 1,001 US dollars, 980 US dollars, and 1,730 US dollars for BMT, PPIclarithromycin, and PPI-amoxicillin, respectively. Estimates after adjustment were US dollars for BMT, 1,118 US dollars for PPI-clarithromycin, and 1,131 US dollars for PPI-amoxicillin. Key model assumptions that proved retrospectively incorrect were largely unsupported by either empirical evidence or systematic assessment of expert opinion. Organizations with access to medical and pharmacy claims databases should test key assumptions of influential models to determine their validity. Journal peer-review processes should pay particular attention to the basis of model assumptions.

Helicobacter pylori infection in recurrent abdominal pain in children--a prospective study.

A total of 40 children was recruited to assess the role of Helicobacter pylori infection in children with recurrent abdominal pain syndrome. Among 40 children, seven (17.5%) cases were confirmed to have H. pylori infection. All H. pylori-positive patients had active chronic gastritis histologic findings (p < 0.0001); however, the majority of the H. pylori-negative patients had minimal to mild gastritis histologic findings (p = 0.001). Grossly, chronic gastritis picture was present in all children infected with H. pylori and antral nodular gastropathy present in 43%. 71% of H. pylori-positive patients had elevated anti-H. pylori IgG titer; however, 15% in H. pylori-negative patients (p = 0.006). Serum H. pylori assay had a sensitivity of 71% and specificity of 85%; however, sensitivity and specificity of rapid urease test were 86% and 100% respectively. Antral nodularity is a specific, peculiar endoscopic finding of children infected with H. pylori (p = 0.004). Although the present study suggests that H. pylori-related chronic gastritis may play an etiological role in a subgroup of children with RAP syndrome, but the routine screening of H. pylori infection in children with RAP is not recommended, since no compelling data support the significant association between H. pylori infection and RAP syndrome.