PCR-denaturing Gradient Gel Electrophoresis (PCR-DGGE), a method suitable for the detection of microbial species in complex ecosystems, was evaluated for the detection and identification of Helicobacter spp. in feces and stomach tissue of mice. Two commercially available stool antigen tests for clinical diagnostics in humans were also evaluated in the C57Bl/6 mouse model of H. pylori infection. PCR-DGGE detected only Helicobacter ganmani in feces from H. pylori-infected as well as control animals, whereas in stomach specimens it demonstrated the presence of H. pylori in challenged and H. ganmani in control animals. Hence, the method detected DNA only of the predominant Helicobacter spp., which was also shown in cell dilution experiments. The Amplified IDEIA Hp StAR feces antigen test detected H. pylori in feces from all infected animals and generated no false-positive results, whereas the Premier Platinum HpSA-test also detected H. pylori in all infected animals but generated false-positive or equivocal results in 50% of the control animals. Premier Platinum HpSA, as opposed to Hp StAR, cross-reacted with non-pylori Helicobacter spp. in vitro.
The collective effective radiation dose to the population is increasing due to a higher use of computerised tomography. SharpView AB, Linköping, Sweden, has developed an adaptive non-linear post-processing image filtration that may enable the use of lower radiation doses. The present study assessed if a lower dose with image filtration had the same image quality as a higher dose without the filter applied. All imaging was performed on a Siemens Somatom Sensation 16 CT. The parameters used were 120 kV and 200 mAs (40 patients) and 130 mAs without and with image filtering (40 patients), respectively. All studies were quantitatively evaluated for noise and image quality was assessed by visual grading characteristics (VGC) analysis. After image filtration, the noise in the processed images was lowered and the image quality was improved as shown by the VGC analysis. However, images using the higher dose were still ranked as the best in five out of eight criteria as shown by the VGC analysis. Image filtration enhances CT images significantly and further studies will show if 130 mAs with image filtration may be sufficient for clinically general abdominal CT.
Helicobacter pylori is one of the most prevalent human pathogens in the world and is the aetiological agent of gastritis, peptic ulcer disease and gastric malignancies. In addition H. pylori and other novel members of the genus are capable of successfully colonising the bile-rich niche of the upper intestine and are associated with a diverse range of intestinal pathologies. Surface-enhanced laser desorption/ionisation-time of flight mass spectrometry was used to analyse surface extracts from H. pylori, Helicobacter bilis, Helicobacter pullorum and "Helicobacter sp. flexispira" to characterise cell surface changes following bile stress. The system detected two distinct response patterns to bile stress on the cell surface of Helicobacter spp. in vitro. The first involved the increase under bile stress of peaks at 7.6 and 7.9 kDa for H. billis and H. pullorum, respectively. In contrast both "Helicobacter sp. flexispira" and a clinical isolate of H. pylori had similar response profiles to bile stress. Both strains had at least three low mass peaks decreased under bile stress and a single peak induced by bile stress. The present study has established the use of ProteinChip(R) technology to analyse helicobacter-related proteomics. Specifically this study has established that different patterns are generated in response to bile stress among various pathogenic Helicobacter spp. which may give insights into the ability of these strains to colonise different niches.
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