Validated accuracy of a novel urea breath test for rapid Helicobacter pylori detection and in-office analysis.

BACKGROUND: A novel 14C-urea breath test (UBT) was developed to detect the presence of Helicobacter pylori by bench analysis in office, enabling the practitioner to readily reveal H. pylori infection. AIM: To validate the novel UBT (Heliprobe) versus conventional UBT. METHODS: Pretreatment (n = 203) and post-treatment (n = 147) detection of H. pylori. Additional tests with encapsulated 14C-urea (n = 37) were validated. After intake of liquid or encapsulated 14C-urea, exhaled 14CO2 in breath was trapped in benzethoniumhydroxide/ethanol, or adsorbed to LiOH-soaked pads on a dry cover surface (Heliprobe BreathCard). The amount of adsorbed 14C was detected using a beta-scintillator or two Geiger-Müller counters operating in parallel (Heliprobe Analyzer). RESULTS: For pretreatment detection, we found full concordance between the UBTs, with 100% sensitivity and specificity (CI 95-100% and 97-100%, respectively) and strong agreement (r = 0.80, CI 0.75-0.85; kappa = 1, CI 0.86-1.14; P < 0.0001). Similarly, for post-treatment follow-up detection, sensitivity and specificity were 100% (CI 85-100% and 97-100%, respectively) with significant agreement (r = 0.48, CI 0.34-0.59; kappa = 1, CI 0.84-1.16; P < 0.0001). The use of encapsulated 14C-urea did not change agreement between the tests. Sensitivity and specificity were 100% (CI 72-100% and 87-100%, respectively) with strong agreement between the tests (r = 0.71, CI 0.50-0.84; kappa = 1, CI 0.68-1.32; P < 0.0001). CONCLUSION: The novel Heliprobe UBT, with either liquid or encapsulated 14C-urea, seems equi-efficacious to conventional UBT in fulfilling its role as the non-invasive gold standard for detection of H. pylori.

Different nest predator faunas and nest predation risk on ground and shrub nests at forest ecotones: an experiment and a review.

This study examined predator faunas of artificial ground and shrub nests and whether nest predation risk was influenced by nest site, proximity to forest edge, and habitat structure in 38 grassland plots in south-central Sweden. There was a clear separation of predator faunas between shrub and ground nests as identified from marks in plasticine eggs. Corvids accounted for almost all predation on shrub nests whereas mammals mainly depredated ground nests. Nest predation risk was significantly greater for shrub than for ground nests at all distances (i.e. 0, 15 and 30 m) from the forest edge. However, nest predation risk was not significantly related to distance to forest edge, but significantly increased with decreasing distance to the nearest tree. Different corvid species robbed nests at different distances from the forest edge, with jays robbing nests closest to edges. We conclude that the relationship between the predation risk of grassland bird nests and distance to the forest edge mainly depends on the relative importance of different nest predator species and on the structure of the forest edge zone. A review of published articles on artificial shrub and ground nest predation in the temperate zone corroborated the results of our own study, namely that shrub nests experienced higher rates of depredation in open habitats close to the forest edge and that avian predators predominantly robbed shrub nests. Furthermore, the review results showed that predation rates on nests in general are highest <50 m inside the forest and lower in open as well as forest interior habitats (≥50 m from the edge).