Faculty Bibliography

BACKGROUND: The presence of Helicobacter pylori in pediatric population has been associated with recurrent abdominal pain (RAP), although this association is unclear. One of the major problems in studying the role of H. pylori in RAP is that methods used to detect the bacteria in children have poor sensitivity and specificity. The aims of the present study were to determine the prevalence of H. pylori in pediatric patients with RAP in northeastern Mexico and to assess the diagnostic utility of invasive tests and serology in this population. METHODS: A total of 40 patients (mean age, 7.9 years; range 2-16 years; F: M, 0.81), who underwent an endoscopy procedure for RAP, were studied. The presence of H. pylori was assessed using invasive diagnostic tests (culture, rapid urease test, polymerase chain reaction and histology) and one non-invasive test: determination of IgG antibodies. The prevalence of H. pylori in the present group and the diagnostic utility for each test were evaluated. RESULTS: The prevalence of H. pylori in the present pediatric group with RAP was 12.5-42.5% depending on the criteria of positivity used. The non-invasive methods (serology) had acceptable values in sensitivity and specificity in comparison with invasive tests. CONCLUSIONS: This is the first report on prevalence of H. pylori in pediatric patients with RAP from the northeastern region of Mexico. The prevalence of H. pylori was low compared with the adult population in the same geographic region. Serology had the best diagnostic utility

BACKGROUND: Cancer may follow exposure to an environmental agent after many decades. The bacterium Helicobacter pylori, known to be acquired early in life, increases risk for gastric adenocarcinoma, but other factors are also important. In this study, we considered whether early-life family structure affects the risk of later developing gastric cancer among H. pylori+ men. METHODS AND FINDINGS: We examined a long-term cohort of Japanese-American men followed for 28 y, and performed a nested case-control study among those carrying H. pylori or the subset carrying the most virulent cagA+ H. pylori strains to address whether family structure predicted cancer development. We found that among the men who were H. pylori+ and/or cagA+ (it is possible to be cagA+ and H. pylori- if the H. pylori test is falsely negative), belonging to a large sibship or higher birth order was associated with a significantly increased risk of developing gastric adenocarcinoma late in life. For those with cagA+ strains, the risk of developing gastric cancer was more than twice as high (odds ratio 2.2; 95% confidence interval 1.2-4.0) among those in a sibship of seven or more individuals than in a sibship of between one and three persons. CONCLUSIONS: These results provide evidence that early-life social environment plays a significant role in risk of microbially induced malignancies expressing five to eight decades later, and these findings lead to new models to explain these interactions

BACKGROUND: Guillain-Barre syndrome is the most common cause of acute neuromuscular paralysis and is considered a post-infectious disease. METHODS: Twenty patients with Guillain-Barre syndrome admitted to the Neurosciences Centre at the All India Institute of Medical Sciences from November 1997 to August 1998 were investigated for evidence of antecedent infections. This case-control study included 2 controls for each patient, one a household control and the other an age- and sex-matched hospital control suffering from a neurological illness other than Guillain-Barre syndrome. Evidence of recent Campylobacter jejuni infection was investigated by culture and serology, and for Mycoplasma pneumoniae by serology. RESULTS: There was evidence of recent C. jejuni infection in 35% of the patients compared with 25% of household controls and none of the hospital controls. M. pneumoniae infection was seen in 50% of patients compared with 25% of household controls and 15% of hospital controls. About one-third of the patients (30%) had evidence of both infections. The association of both infections in patients was found to be statistically significant as compared to hospital controls. CONCLUSION: C. jejuni and M. pneumoniae may be important antecedent illnesses in patients with Guillain-Barre syndrome in India

GOAL: To study the rate at which Helicobacter pylori infection is treated in an immigrant cohort after diagnosis by esophagogastroduodenoscopy (EGD). BACKGROUND: Gastric cancer is the second leading cause of cancer death worldwide, and is especially prevalent in East Asia; immigrants from this part of the world remain at higher risk. Infection with H. pylori is a known risk factor for gastric cancer. There have been no studies of completion of H. pylori treatment in immigrant populations. STUDY: Prospective cohort study of East Asian immigrants diagnosed with H. pylori infection who underwent EGD in a gastric cancer screening protocol. Our primary outcome was self-report or chart evidence of completion of treatment of H. pylori. RESULTS: Sixty-eight of the 126 participants (54%) tested positive for H. pylori infection on EGD. Forty-nine (72%) were seen for a follow-up visit at one of the clinics involved in the study. According to clinic records, 39 of these 49 participants (57% of all H. pylori-positive participants) were prescribed treatment. Only 31 participants (46%) completed treatment. Of possible explanatory factors, only having a 'regular doctor' was significantly associated with treatment completion (odds ratio=5.6; 95% confidence interval, 1.2-25.0). CONCLUSIONS: In a sample of Asian immigrants, the rate of treatment of H. pylori infection, a potentially modifiable risk factor, was lower than expected. Having a 'regular doctor' appeared to increase the likelihood of receiving appropriate follow-up care

BACKGROUND: Invasive and noninvasive tests are used for the diagnosis of Helicobacter pylori infection. The aim of this study was to determine the diagnostic utility of rapid urease test (RUT), culture, histology and serology for the diagnosis of H. pylori in patients with different clinical presentations. METHODS: We studied 527 consecutive patients (mean age, 52.5 years; F:M, 1.3; age range 15-89 years) enrolled at the Hospital Universitario, Universidad Autonoma de Nuevo Leon. Patients had gastric cancer (GC, 9.1%), non-ulcer dyspepsia (NUD, 81.4%), or peptic ulcer disease (PUD, 9.1%). The infection by H. pylori was determined by histology, rapid urease test, culture, and serology. Patients were determined as infected with H. pylori if at least a) two invasive tests were positive and b) two tests were positive (invasive or non-invasive). Diagnostic utility was calculated for each assay. RESULTS: Prevalence of infection in the whole studied population was 50.9%. In NUD patients the prevalence was 51.3%, in PUD patients 58.3%, and in GC patients 39.6%. When we used the first diagnostic criteria, for the whole studied population, the RUT was the most reliable test, followed by the culture. Histology had the best sensitivity for the whole studied population and NUD patients and RUT had the best sensitivity value for the GC patients. In the whole studied population, NUD and GC patients, RUT and culture had the best specificity, accuracy and PPV. For PUD patients, serology had the best performance. When we used the second diagnostic criteria, histology and serology had a better performance compared with the results obtained with the first diagnostic criteria. CONCLUSIONS: Diagnostic utility of the tests varies according to the clinical presentations, which should be considered in the selection of the diagnostic test for the detection of H. pylori