View clinical trials related to Helicobacter Infections.
Filter by:Helicobacter pylori (Hp) is a major cause of chronic-active gastritis and primary duodenal ulcers, and is strongly linked to gastric cancer. Most Hp infections worldwide are acquired in childhood. Why some individuals develop symptomatic disease is unclear and, until recently, no studies critically evaluated the role of pediatric Hp strains and/or host factors in disease outcomes. Over the past 5 years of National Institutes of Health (NIH) funding, 486 children from Atlanta, Cleveland, and Miami were enrolled; 184 (38%) were Hp-infected. Race (African American) and younger age, in conjunction with Hp strains expressing cagA and vacAs1B, were shown to be risk factors for both esophageal and gastric disease, suggesting a different disease paradigm from Hp-infected adults. Using the updated Sydney system, the investigators demonstrated a histopathologic spectrum in children, which included novel observations of atrophic gastritis with intestinal metaplasia. Overall hypothesis for competitive renewal: disease manifestations in Hp-infected children are influenced by specific host factors (i.e., race, immune phenotype), environmental exposures, and specific virulence factors of infecting Hp strains. Specific aims: 1. Using well defined cases and controls, further characterize specific host factors and environmental exposures contributing to symptomatic childhood infection emphasizing targeted enrollment in specific age, gender and demographic strata to facilitate detection of significant differences not attained previously and follow-up of 2 established specific cohorts to ascertain immune response natural history. 2. Utilize gene-array technology for the whole Hp genome assessment and bacterial gene expression of specific virulence determinants associated with pediatric Hp strains. 3. Further characterize the host immunologic and mucosal response in Hp-infected children. Hp-infected symptomatic endoscopy cases at the investigators' established 3 clinical centers of high, moderate and low Hp prevalence will be compared with age-matched Hp-infected asymptomatic and uninfected symptomatic controls. Two geographically and demographically distinct centers have been added to provide additional geographic and subject representativeness to the patient cohort. The updated Sydney system will be employed to assess gastric histopathology severity and phenotype in newly enrolled cases in specific age, gender and demographic strata and follow-up of the two "novel" cohorts established in the past 5 years: a) atrophic gastritis; and b) esophageal and gastric disease groups enabling a comprehensive, multivariate evaluation of the natural history of Hp-infected children in two distinct disease paradigms. Using molecular methods (multiplex [MP]-PCR, RT-PCR) and a micro ELISPOT assay on peripheral blood mononuclear cells (PBMCS), Th1, Th2, Th3 or balanced Th1/Th2 response will be determined to further characterize the Hp-infected child's immune response phenotype. The investigators propose to further their previous work with critically lacking studies from a multivariate approach, leading to a better understanding of the gastroduodenal disease sequelae and overall pathobiology of Hp infection in humans.
The purpose of this study is to determine if Helicobacter pylori (H. pylori) gastritis results in abnormal iron metabolism in patients with iron deficiency anemia (IDA), and to determine if this is due to strain variations in the H. pylori organism.
Helicobacter pylori (H. pylori) eradication increases the serum pepsinogen (PG) I/PG II ratio and the percentage change in PG I/PG II ratios was found to be a useful marker of H. pylori eradication (e.g., the PG method). We studied whether the PG method could be an early diagnostic marker of H. pylori eradication even in patients persistently treated with a proton pump inhibitor. Sixty-two H. pylori-positive patients underwent H. pylori-eradication therapy, followed by treatment with a PPI to cure ulcers. Serum levels of PG I and PG II were measured before, at the end of, and at 4 weeks after the eradication therapy. At more than one month after the end of treatments, 13C-urea breath test (UBT) was performed. The cut-off values of percentage changes in PG I/PG II ratios for the diagnosis of eradication of H. pylori were set in proportion to PG I/PG II ratios before eradication in accordance with our previous report. Using the results of UBT as the standard, the percentage change in serum PG I/PG II ratios is useful as an early diagnostic marker for judgment of H. pylori eradication irrespective of PPI treatment.
Proton pump inhibitors (PPIs) are mainly metabolized in the liver by CYP2C19, one of the cytochrome P450 isoenzymes, which shows a genetic polymorphism associated with enzyme activities. The most essential role of a PPI in H. pylori eradication therapy is to make antibiotics more stable and bioavailable in the stomach by raising intragastric pH to neutral levels. Most patients who have failed in the eradication of H. pylori infection by triple therapy with a PPI, amoxicillin (AMPC) and clarithromycin (CAM) at standard doses have extensive metabolizer (EM) genotypes of CYP2C19 and/or are infected with CAM-resistant strains of H. pylori. Four-times daily dosing of a PPI could achieve complete gastric acid inhibition. Dual therapy with 4-times daily dosing of a PPI and AMPC could yield sufficient re-eradication rates in patients with EM genotype of CYP2C19. Metronidazole (MNZ)-based re-eradication therapy, such as triple PPI/AMPC/MNZ therapy, also achieved high eradication rates and has been recommended as the second line therapy in Japan. But carcinogenic actions of MNZ have been unclear. The purpose of this study is to compare the re-eradication rates of H. pylori infection by the dual high-dose PPI/AMPC therapy and triple PPI/AMPC/MNZ therapy, and to validate the efficacies of these re-eradication regimens as second line eradication therapies.
The objective is to evaluate the utility of a breath ammonia sensing device. In this study we will assess the effect of H. pylori infection on breath ammonia levels by measuring whether there is a change in the pattern or quantity of breath ammonia seen in H. pylori positive patients compared to H. pylori negative patients.
The objective of this trial is to find the rationale and the optimal dose and duration of regimen for the eradication of H. pylori infection using different proton pump inhibitors.
The aims of this prospective study are: (1) to prospectively investigate the "true" prevalence rate, the acquisition and spontaneous clearance of H. pylori infection year by year in the population whose ages between seven and fifteen. (2) to explore the risk factors of transmission of H. pylori infection in Taiwan. (This information may be use as the guide for conduction of the national policy of public health and disease prevention.)
Based on a universal eradication of H. pylori in an offshore island (Matsu) with a high prevalence of gastric cancer as well as premalignant gastric lesion, we first examined the infection rate of H. pylori. Secondly, we evaluated the efficacy of clarithromycin-based triple therapy with a levofloxacin-based rescue treatment. And thirdly, we tested the hypothesis that whether the cure of H. pylori can reverse the premalignant gastric lesion. Fourth, we determine the cost-effectiveness of this intervention. The gene-environment interaction will be addressed regarding gastric cancer carcinogenesis. Finally, the incident rate of gastric cancer would be followed in this cohort.
The eradication rate of the standard H. pylori eradication therapy (such as the triple therapy with a proton pump inhibitor [PPI], amoxicillin and clarithromycin) depends on bacterial susceptibility to clarithromycin and genotypes of CYP2C19 in patients. The investigators intend to investigate whether the tailored therapy based on the two above-mentioned factors increases the cure rate of the initial eradication therapy.
This study will examine whether infection with Helicobacter pylori bacteria may cause inflammation of the eye's surface. Although most people who are infected with H. pylori do not have symptoms, the bacteria can cause several diseases, including gastritis-stomach inflammation, stomach ulcers or, rarely, stomach cancer, and certain types of lymphoma. H. pylori has also been associated with autoimmune disorders, in which the patient's immune system attacks the body's own tissues. People who have been infected with H. pylori, with and without dry eye, may be eligible for this study. Candidates are screened with a medical history, a blood test to determine H. pylori infection, and an eye examination. The examination includes measurements of visual acuity, eye pressure, and tear production. To measure the amount of tear production, a small piece of filter paper is inserted over the eyelid on the side and collects tears over a 5-minute period. Drops of two colored dyes (orange and green) are placed in the eyes to see if there are any dry areas. Screening also includes examination of the pupils and eye movements, the lens, and the back of the eye, including the retina. Participants will also have a few cells collected from the surface of the eye. After the eyes are numbed with anesthetic eye drops, a swab (like a Q-tip) is rolled over the surface of the white part of the eye to collect small samples of the superficial layer of the conjunctiva - a transparent membrane covering the eyeball. The specimens are analyzed by special laboratory techniques to determine whether H. pylori has infected the eye.