The Development of Therapeutic and Preventive Vaccines for Gastric Cancer and Helicobacter pylori

DIMT1 overexpression correlates with progression and prognosis in gastric carcinoma

We investigated the expression of dimethyladenosine transferase 1 homolog (DIMT1) in human gastric carcinoma (GC) tissues, pericarcinoma histologically normal tissues, and normal gastric tissues and explored its clinical significance. Immunohistochemistry staining was used to detect the expression of DIMT1, and the findings were compared with clinicopathological features of patients with GC. The result also was ascertained by Western blotting. The Kaplan-Meier method and log-rank test were used to compare the overall survival rate and time in the DIMT1 low-level and high-level expression groups. Immunohistochemical staining indicated that the expression of DIMT1 in GC tissues (65/75; 86.7%) was significantly more common (P<.001) than that in pericarcinoma histologically normal tissues (14/75; 18.7%) and normal gastric tissues (2/12; 16.7%). High expression of DIMT1 correlated closely with differentiation (P=.023), invasion (P=.042), lymph node metastasis (P=.008), distant metastasis (P=.006), and TNM stage (P=.013). Western blotting showed that DIMT1 expression correlated positively with TNM stage and implied that more advanced TNM stage was accompanied by higher expression of DIMT1 (P<.001). Kaplan-Meier survival analysis showed that high DIMT1 expression correlated significantly (P<.001) with a poor prognosis. Our data suggest that DIMT1 is a useful molecular biomarker to predict tumor progression and prognosis in patients with GC.

Microfluidic optoelectronic sensor for salivary diagnostics of stomach cancer

We present a microfluidic optoelectronic sensor for saliva diagnostics with a potential application for non-invasive early diagnosis of stomach cancer. Stomach cancer is the second most common cause of cancer-related deaths in the world. The primary identified cause is infection by a gram-negative bacterium Helicobacter pylori. These bacteria secrete the enzyme urease that converts urea into carbon dioxide (CO2) and ammonia (NH3), leading to their elevated levels in breath and body fluids. The proposed optoelectronic sensor will detect clinically relevant levels of CO2 and NH3 in saliva that can potentially be used for early diagnosis of stomach cancer. The sensor is composed of the embedded in a microfluidic device array of microwells filled with ion-exchange polymer microbeads doped with various organic dyes. The optical response of this unique highly diverse sensor is monitored over a broad spectrum, which provides a platform for cross-reactive sensitivity and allows detection of CO2 and NH3 in saliva at ppm levels.

Comparison of the efficacy of triple versus quadruple therapy on the eradication of Helicobacter pylori and antibiotic resistance

OBJECTIVE

Our aim was to compare the efficacy and safety of Helicobacter pylori (H. pylori) eradication with pantoprazole-based 7-day standard triple therapy (PAC) and 10-day quadruple therapy (PBMT), and to study the primary resistance of H. pylori to amoxicillin, clarithromycin, metronidazole and tetracycline.

METHODS

A total of 170 patients with non-ulcer dyspepsia (NUD) and H. pylori infection were allocated to two study groups. The PAC group received pantoprazole 40 mg b.i.d., amoxicillin 1.0 g b.i.d. and clarithromycin 500 mg b.i.d. for 7 days; the PBMT group received pantoprazole 40 mg b.i.d., colloidal bismuth subcitrate 220 mg b.i.d, metronidazole 400 mg t.i.d. and tetracycline 750 mg b.i.d. for 10 days. A total of 80 H. pylori strains were isolated and antibiotic resistance was measured by the agar dilution method.

RESULTS

A total of 166 patients completed the therapy. The intention-to-treat eradication rates in the PAC and PBMT groups were 63.5% and 89.4%, respectively (P < 0.05). By per protocol analysis, the eradication rates of the two groups were 65.1% and 91.6%, respectively (P < 0.05). Overall 77 clinical isolated H. pylori strains were cultured successfully. The H. pylori primary resistance rates to metronidazole and clarithromycin were 41.6% and 20.8%, respectively, whereas all the H. pylori isolates were sensitive to amoxicillin and tetracycline.

CONCLUSION

The efficacy of PAC declines in many regions in China because of high antibiotic resistance rates. The PBMT regimen achieved a high eradication rate of H. pylori and might be used as a first-line therapy.

Review article: 'true' re-infection of Helicobacter pylori after successful eradication--worldwide annual rates, risk factors and clinical implications

BACKGROUND

The incidence of 'true' re-infection with Helicobacter pylori after successful eradication remains uncertain.

AIM

To determine the worldwide rates, risk factors and clinical implications of 'true' re-infection of Helicobacter pylori. 'True' re-infection of H. pylori is defined as the situation where tests for H. pylori infection, which were negative for 12 months after eradication, become positive again at a later stage.

RESULTS

Thirty six studies were identified through a literature search to be able to produce annual rates of 'true' re-infection, and data from 33 original articles were considered reliable and adequate in the further review. Generally, the reported rates varied from 0% to 23.4% in adults and from 1.9% to 9.6% in children. Most studies from developed countries reported rates of less than 1%, whereas relatively higher rates were reported in most of the developing countries. Small sample sizes included in the studies appeared to be associated with increased re-infection rates. Interfamilial transmission is the major cause of re-infection, although iatrogenic re-infection through contaminated endoscopic equipment has been reported.

CONCLUSION

Helicobacter pylori re-infection is not a concern in a clinical setting, especially in the developed world; however, caution must be exercised in most developing countries.

The seroepidemiology of Helicobacter pylori infection in Australia

BACKGROUND

Infection with Helicobacter pylori is common worldwide and a significant cause of upper gastrointestinal disease. Prevalence of this infection varies in different population groups internationally. Because of the invasiveness of specimen collection for bacteriologic diagnosis and the expense of tests such as labeled urea breath tests, serology is the most feasible means of determining the population epidemiology of H. pylori. The aim of this study was to describe the seroepidemiology of H. pylori infection in Australia.

METHODS

H. pylori-specific ELISA for the presence of IgG antibodies was performed on a representative sample of 2413 sera from Australia in 2002, using validated serosurveillance methods.

RESULTS

The overall seroprevalence of H. pylori infection in Australia was 15.1% in 2002, with no statistical difference between genders. Seropositivity rates increased progressively with age, ranging between 4.0% in the 1-4-year-olds and 23.3% in the 50-59-year-olds.

CONCLUSIONS

The prevalence of infection with H. pylori in Australia was lower than rates reported in other developed countries, at 15.4%. This study provides important baseline measurements for future preventive measures including vaccine research and development. Further studies to determine subgroups at higher risk of infection may help target the more susceptible populations.