Use this URL to cite or link to this record in EThOS:
Title: Application of molecular techniques to the study of Helicobacter pylori and gastric cancer
Author: Ismail, H.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2004
Availability of Full Text:
Access from EThOS:
Previous research has demonstrated a link between H. pylori infection and gastric malignancies. The objective of the study was to investigate this correlation and evaluate detection methods for the diagnosis of this pathogen. The performance of the PCR assay for the detections of H. pylori in gastric tissues was assessed. The PCR assay was found to be highly sensitive for identifying the presence of H. pylori in gastric biopsies compared to other detection techniques such as histological examination and rapid urease test. In addition, the H. pylori-PCR detection method was used to determine the prevalence pattern of the organism in two different geographical populations i.e. British and Saudi patients. This analysis revealed that the prevalence rate of H. pylori infection is significantly higher in the Saudi patients(64%) than in the British patients (42%). In order to increase the efficiency of the PCR assay and to render it capable of detecting the organism at non-gastric sites, a new nested PCR assay was developed using the internal region of the fragment of H. pylori genome that amplified by the EHC-L/E primer, and employed to identify H. pylori DNA in the oral cavity samples. Nested PCR has detected H. pylori in dental plaque samples of 83% patients with histologically proven gastric infection. Thus, this technique may be a valuable non-invasive initial screening for the selection of endoscopy candidates for monitoring the efficacy of H. pylori eradication therapy and for epidemiological studies of H. pylori related research. The H. pylori PCR-genotyping assay was also utilised in this study to determine vacA  and cagA status of H. pylori strains infecting British and Saudi patients with different clinical outcomes. The important finding of this assay is that H. pylori characterises as cagA+ and vacA type s1m1 were significantly associated with the presence of intestinal metaplasia and gastric cancer in both of these different populations (British and Saudi individuals). Moreover, a strong association was discovered between H. pylori-cagA+ and p53 mutations in inflamed gastric mucosa, which is a central feature of the multistep process leading to gastric cancer. Therefore, this supports the hypothesis that H. pylori is an important carcinogenic factor in the occurrence of gastric malignant disease in the stomach.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available