Pepsinogen testing for evaluation of the success of Helicobacter pylori eradication at 4 weeks after completion of therapy

BACKGROUND AND OBJECTIVE

Pepsinogen levels in plasma are increased by inflammation in the gastric mucosa, including inflammation resulting from Helicobacter pylori infection. A decrease in pepsinogen II level has been suggested as a reliable marker to confirm the successful eradication of infection. The aim of our study was to evaluate the potential role of pepsinogens I and II, gastrin-17 and H. pylori antibodies in confirming successful eradication.

MATERIAL AND METHODS

Altogether 42 patients (25 women, 17 men), mean age 45 years (range 23-74), were enrolled. Pepsinogens I and II, gastrin-17 and H. pylori IgG antibodies were measured in plasma samples using an ELISA test (Biohit, Oyj., Finland) before the eradication and 4 weeks after completing the treatment. The success of eradication was determined by a urea breath test.

RESULTS

Eradication was successful in 31 patients (74%) and unsuccessful in 11 patients (26%). Pepsinogen II decreased significantly in both the successful (P=0.029) and unsuccessful (P=0.042) eradication groups. Pepsinogen I decreased significantly in the successful (P=0.025) but not the unsuccessful (P=0.29) eradication group. The pepsinogen I/II ratio increased in the successful eradication group (P=0.0018) but not in the group in which treatment failed (P=0.12). There were no differences in gastrin-17 or H. pylori antibody values.

CONCLUSIONS

A decrease in pepsinogen II levels cannot be used as a reliable marker for the successful eradication of H. pylori 4 weeks after the completion of treatment. The increase in pepsinogen I/II ratio reflects differences in pepsinogen production following the eradication irrespective of improvement in atrophy.

Management of Helicobacter pylori-related diseases in the Baltic States

Helicobacter pylori infection has been recognized as the main trigger of stomach-related diseases. The huge variation in H. pylori infection patterns across the globe requires targeted research and close monitoring of this infection in different regions. The Baltic countries have witnessed enormous changes in socioeconomic conditions in the last years. Evolution of H. pylori infection and related diseases has been a key interest of gastroenterology centers in the Baltic States over the last two decades, translating into up-to-date scientific data that are valuable locally and on the European level. The East-West gradient in the prevalence of H. pylori infection is still evident in the Baltic countries, but the gap is becoming smaller, and similar trends are expected for the coming years. Clarithromycin-based triple therapy remains the first-line treatment of H. pylori in the region; however, careful monitoring of resistance rates in the future remains highly relevant, though routine resistance testing is not available in all the countries. A high prevalence of gastric cancer is still notable in the Baltic States; nevertheless, a steady decline in gastric cancer incidence in Lithuania, Latvia and Estonia is present and expected to be continuing during the coming decades. Currently, H. pylori-related diseases still constitute a substantial part of gastroenterologists' workload in the region. This paper reviews epidemiological, diagnostic, treatment as well as basic research trends on H. pylori infection and related diseases in the Baltic States during the last two decades.

BRCA1 gene-related hereditary susceptibility to breast and ovarian cancer in Latvia

PURPOSE

In this report, we summarise data on BRCA1 gene analysis in Latvia to characterise criteria of genetic testing for breast and ovarian cancer susceptibility.

MATERIAL/METHODS

Analysis by SSCP/HD, MALDI-TOF mass spectrometry or DNA sequencing was used for mutation detection. Mutations identified were confirmed by direct DNA sequencing.

RESULTS

Out of 1068 breast and 231 ovarian cancer patients from different families: 58 carried the c.5266dupC and 43 carried the c.4035delA mutations. Every 4th patient in our study did not report cancer in the family. The breast cancer was diagnosed earlier in carriers of the c.5266dupC than in carriers of the c.4035delA (p=0.003). The incidence of breast or ovarian cancer does not differ among the 2 mutation carriers in our patient group. The nature of the c.5266dupC mutation might be more deleterious.

CONCLUSIONS

We recommend the screening of 4 founder BRCA1 mutations in all breast and ovarian cancer patients in Latvia at diagnosis of disease regardless of family history or age. The BRCA1 screening can be carried out efficiently using the MALDI-TOF mass spectrometry mutation detection method developed in the Biomedical Research and Study Centre (Riga, Latvia).

Gastritis staging: interobserver agreement by applying OLGA and OLGIM systems

Atrophic gastritis remains a difficult histopathological diagnosis with low interobserver agreement. The aim of our study was to compare gastritis staging and interobserver agreement between general and expert gastrointestinal (GI) pathologists using Operative Link for Gastritis Assessment (OLGA) and Operative Link on Gastric Intestinal Metaplasia (OLGIM). We enrolled 835 patients undergoing upper endoscopy in the study. Two general and two expert gastrointestinal pathologists graded biopsy specimens according to the Sydney classification, and the stage of gastritis was assessed by OLGA and OLGIM system. Using OLGA, 280 (33.4 %) patients had gastritis (stage I-IV), whereas with OLGIM this was 167 (19.9 %). OLGA stage III- IV gastritis was observed in 25 patients, whereas by OLGIM stage III-IV was found in 23 patients. Interobserver agreement between expert GI pathologists for atrophy in the antrum, incisura angularis, and corpus was moderate (kappa = 0.53, 0.57 and 0.41, respectively, p < 0.0001), but almost perfect for intestinal metaplasia (kappa = 0.82, 0.80 and 0.81, respectively, p < 0.0001). However, interobserver agreement between general pathologists was poor for atrophy, but moderate for intestinal metaplasia. OLGIM staging provided the highest interobserver agreement, but a substantial proportion of potentially high-risk individuals would be missed if only OLGIM staging is applied. Therefore, we recommend to use a combination of OLGA and OLGIM for staging of chronic gastritis.

Gene polymorphisms of micrornas in Helicobacter pylori-induced high risk atrophic gastritis and gastric cancer

BACKGROUND AND AIMS

MicroRNAs (miRNAs) are known for their function as translational regulators of tumor suppressor or oncogenes. Single nucleotide polymorphisms (SNPs) in miRNAs related genes have been shown to affect the regulatory capacity of miRNAs and were linked with gastric cancer (GC) and premalignant gastric conditions. The purpose of this study was to evaluate potential associations between miRNA-related gene polymorphisms (miR-27a, miR-146a, miR-196a-2, miR-492 and miR-608) and the presence of GC or high risk atrophic gastritis (HRAG) in European population.

METHODS

Gene polymorphisms were analyzed in 995 subjects (controls: n = 351; GC: n = 363; HRAG: n = 281) of European descent. MiR-27a T>C (rs895819), miR-146a G>C (rs2910164), miR-196a-2 C>T (rs11614913), miR-492 G>C (rs2289030) and miR-608 C>G (rs4919510) SNPs were genotyped by RT-PCR.

RESULTS

Overall, SNPs of miRNAs were not associated with the presence of GC or HRAG. We observed a tendency for miR-196a-2 CT genotype to be associated with higher risk of GC when compared to CC genotype, however, the difference did not reach the adjusted P-value (odds ratio (OR) - 1.46, 95% confidence interval (CI) 1.03-2.07, P = 0.032). MiR-608 GG genotype was more frequent in GC when compared to controls (OR -2.34, 95% CI 1.08-5.04), but significance remained marginal (P = 0.029). A similar tendency was observed in a recessive model for miR-608, where CC + CG vs GG genotype comparison showed a tendency for increased risk of GC with OR of 2.44 (95% CI 1.14-5.22, P = 0.021). The genotypes and alleles of miR-27a, miR-146a, miR-196a-2, miR-492 and miR-608 SNPs had similar distribution between histological subtypes of GC and were not linked with the presence of diffuse or intestinal-type GC.

CONCLUSIONS

Gene polymorphisms of miR-27a, miR-146a, miR-196a-2, miR-492, miR-492a and miR-608 were not associated with the presence of HRAG, GC or different histological subtypes of GC in European subjects.

Molecular diagnostics in gastric cancer

Despite recent advances in individualised targeted therapy, gastric cancer remains one of the most challenging diseases in gastrointestinal oncology. Modern imaging techniques using endoscopic filter devices and in vivo molecular imaging are designed to enable early detection of the cancer and surveillance of patients at risk. Molecular characterisation of the tumour itself as well as of the surrounding inflammatory environment is more sophisticated in the view of tailored therapies and individual prognostic assessment. The broad application of high throughput techniques for the description of genome wide patterns of structural (copy number aberrations, single nucleotide polymorphisms, methylation pattern) and functional (gene expression profiling, proteomics, miRNA) alterations in the cancer tissue lead not only to a better understanding of the tumour biology but also to a description of gastric cancer subtypes independent from classical stratification systems. Biostatistical means are required for the interpretation of the massive amount of data generated by these approaches. In this review we give an overview on the current knowledge of diagnostic methods for detection, description and understanding of gastric cancer disease.

Geographical variation in the exhaled volatile organic compounds

Breath-gas analysis has demonstrated that concentration profiles of volatile organic compounds (VOCs) could be used for detecting a variety of diseases, among them gastric cancer (GC) and peptic ulcer disease (PUD). Here, we explore how geographical variation affects the disease-specific changes in the chemical composition of breath samples, as compared to control states (less severe gastric conditions). Alveolar exhaled breath samples from 260 patients were collected at two remotely different geographic locations (China and Latvia), following similar breath-collection protocols. Each cohort included 130 patients that were matched in terms of diagnosis (37 GC/32 PUD/61 controls), average age, gender ratio and smoking habits. Helicobacter Pylori infection, which is a major cause for GC and PUD, was found in part of the patients, as well as in part of the controls, at both locations. The breath samples were analyzed by gas chromatography/mass spectrometry, using the same equipment and protocol-of-experiment. We observed similar characteristic differences in the chemical composition of the breath samples between the study groups at the two locations, even though the exact composition of the breath samples differed. Both in China and Latvia, the GC patients and controls could be distinguished by differences in the average levels of 6-methyl-5-hepten-2-one; PUD patients were distinguished from controls by the levels of aromatic compounds and alcohols; GC and PUD patients could not be distinguished at either site. This pilot study indicates the limitations of chemical breath-gas analysis alone for identifying gastric diseases based on the concentration profiles of separate VOCs in international patient cohorts. We assume that these limitations would apply to other diseases as well. The presented data could potentially be useful for developing an alternative, universally applicable diagnostic method that relies on the detection of changes in the collective patterns of the disease-specific classes of exhaled VOCs.

Systematic review of the diagnosis of gastric premalignant conditions and neoplasia with high-resolution endoscopic technologies

AIM. The aim of the article is to systematically review the current evidence on the diagnostic use of narrow band imaging (NBI), flexible spectral imaging color enhancement (FICE) and endoscopic image enhancement technology i-scan endoscopies for gastric precancerous and cancerous lesions. MATERIALS AND METHODS. Original manuscripts were searched in PubMed until October 2012. Pertinent data were collected and pooled diagnostic accuracy measures were estimated when possible. RESULTs. In total, 38 studies were evaluated. Thirty-one studies were included for NBI and 7 studies for FICE assessment in this systematic review. No article was found meeting inclusion criteria for i-scan endoscopy. The most defined and evaluated outcomes were cancer-related (n = 26). Quality Assessment of Diagnostic Accuracy Studies score varied from 9 to 12 (out of 14). Only few studies assessed the interobserver reliability. On a patient level analysis, NBI's pooled sensitivity, specificity and diagnostic odds ratio were 0.67 (95% CI: 0.61-0.73), 0.81 (95% CI: 0.76-0.85) and 22.71 (95% CI: 12.53-41.1), respectively for diagnosing normal mucosa; 0.86 (95% CI: 0.82-0.90), 0.77 (95% CI: 0.73-0.80) and 17.01 (95% CI: 1.4-207.2) for intestinal metaplasia and 0.90 (95% CI: 0.84-0.94), 0.83 (95% CI: 0.80-0.86) and 47.61 (95% CI: 4.61-491.34) for dysplasia. Owing to the insufficient data and different definitions, we could not aggregate the results for FICE. CONCLUSION. Gastric pattern descriptions have been proposed for NBI and FICE studies by gathering all descriptions in one single description. The classification systems varied between studies, a single description of gastric mucosal features with HR--scopes or at least per technology--will have to be agreed on.

A nanomaterial-based breath test for distinguishing gastric cancer from benign gastric conditions

Background:

Upper digestive endoscopy with biopsy and histopathological evaluation of the biopsy material is the standard method for diagnosing gastric cancer (GC). However, this procedure may not be widely available for screening in the developing world, whereas in developed countries endoscopy is frequently used without major clinical gain. There is a high demand for a simple and non-invasive test for selecting the individuals at increased risk that should undergo the endoscopic examination. Here, we studied the feasibility of a nanomaterial-based breath test for identifying GC among patients with gastric complaints.

Methods:

Alveolar exhaled breath samples from 130 patients with gastric complaints (37 GC/32 ulcers / 61 less severe conditions) that underwent endoscopy/biopsy were analyzed using nanomaterial-based sensors. Predictive models were built employing discriminant factor analysis (DFA) pattern recognition, and their stability against possible confounding factors (alcohol/tobacco consumption; Helicobacter pylori) was tested. Classification success was determined (i) using leave-one-out cross-validation and (ii) by randomly blinding 25% of the samples as a validation set. Complementary chemical analysis of the breath samples was performed using gas chromatography coupled with mass spectrometry.

Results:

Three DFA models were developed that achieved excellent discrimination between the subpopulations: (i) GC vs benign gastric conditions, among all the patients (89% sensitivity; 90% specificity); (ii) early stage GC (I and II) vs late stage (III and IV), among GC patients (89% sensitivity; 94% specificity); and (iii) ulcer vs less severe, among benign conditions (84% sensitivity; 87% specificity). The models were insensitive against the tested confounding factors. Chemical analysis found that five volatile organic compounds (2-propenenitrile, 2-butoxy-ethanol, furfural, 6-methyl-5-hepten-2-one and isoprene) were significantly elevated in patients with GC and/or peptic ulcer, as compared with less severe gastric conditions. The concentrations both in the room air and in the breath samples were in the single p.p.b._v range, except in the case of isoprene.

Conclusion:

The preliminary results of this pilot study could open a new and promising avenue to diagnose GC and distinguish it from other gastric diseases. It should be noted that the applied methods are complementary and the potential marker compounds identified by gas-chromatography/mass spectrometry are not necessarily responsible for the differences in the sensor responses. Although this pilot study does not allow drawing far-reaching conclusions, the encouraging preliminary results presented here have initiated a large multicentre clinical trial to confirm the observed patterns for GC and benign gastric conditions.

European guidelines for quality assurance in colorectal cancer screening and diagnosis: overview and introduction to the full supplement publication

Population-based screening for early detection and treatment of colorectal cancer (CRC) and precursor lesions, using evidence-based methods, can be effective in populations with a significant burden of the disease provided the services are of high quality. Multidisciplinary, evidence-based guidelines for quality assurance in CRC screening and diagnosis have been developed by experts in a project co-financed by the European Union. The 450-page guidelines were published in book format by the European Commission in 2010.  They include 10 chapters and over 250 recommendations, individually graded according to the strength of the recommendation and the supporting evidence. Adoption of the recommendations can improve and maintain the quality and effectiveness of an entire screening process, including identification and invitation of the target population, diagnosis and management of the disease and appropriate surveillance in people with detected lesions. To make the principles, recommendations and standards in the guidelines known to a wider professional and scientific community and to facilitate their use in the scientific literature, the original content is presented in journal format in an open-access Supplement of Endoscopy. The editors have prepared the present overview to inform readers of the comprehensive scope and content of the guidelines.

Markers for gastric cancer premalignant lesions: where do we go?

Only a small proportion of patients infected with Helicobacter pylori develop gastric cancer during their lifetime. At the same time, this type of cancer remains an important cause of mortality globally. The current interventional strategies have not been successful in decreasing the global burden of the disease; therefore, biomarkers for the identification of the individuals at high risk as well as those in the early stage of the disease is of high importance. In addition, predicting the point of no return for the development of the malignancy is of particular interest; whether atrophy, intestinal or spasmolytic polypeptide-expressing metaplasia, or some of their subtypes correspond to this point, still needs to be answered. The current review addresses the place of 'old markers', in particular pepsinogen tests for the identification of increased risk conditions. More data in Caucasian populations are required before these tests can be recommended for routine screening. Several of the host genetic factors are related to the development of sporadic gastric cancer; still their importance is probably not so high as initially thought, and at this stage host genetic factors cannot be used to identify high-risk groups. The detection of specific microRNAs could become a potential field in marker development, and several other new approaches for marker identification are emerging. To achieve the goal, a screening marker has to be not only accurate, but also available and cost-effective in the target populations, many of which are from low-income countries. This has to be considered when developing a marker or set of markers offered for gastric cancer screening programs.

Rationale in diagnosis and screening of atrophic gastritis with stomach-specific plasma biomarkers

BACKGROUND AND AIMS

Atrophic gastritis (AG) results most often from Helicobacter pylori (H. pylori) infection. AG is the most important single risk condition for gastric cancer that often leads to an acid-free or hypochlorhydric stomach. In the present paper, we suggest a rationale for noninvasive screening of AG with stomach-specific biomarkers.

METHODS

The paper summarizes a set of data on application of the biomarkers and describes how the test results could be interpreted in practice.

RESULTS

In AG of the gastric corpus and fundus, the plasma levels of pepsinogen I and/or the pepsinogen I/pepsinogen II ratio are always low. The fasting level of gastrin-17 is high in AG limited to the corpus and fundus, but low or non-elevated if the AG occurs in both antrum and corpus. A low fasting level of G-17 is a sign of antral AG or indicates high intragastric acidity. Differentiation between antral AG and high intragastric acidity can be done by assaying the plasma G-17 before and after protein stimulation, or before and after administration of the proton pump inhibitors (PPI). Amidated G-17 will rise if the antral mucosa is normal in structure. H. pylori antibodies are a reliable indicator of helicobacter infection, even in patients with AG and hypochlorhydria.

CONCLUSIONS

Stomach-specific biomarkers provide information about the stomach health and about the function of stomach mucosa and are a noninvasive tool for diagnosis and screening of AG and acid-free stomach.

Performance of routine Helicobacter pylori tests in patients with atrophic gastritis

BACKGROUND

Decreased density of H. pylori in atrophic gastritis may lead to low sensitivity of the routine tests.

AIMS

To evaluate the accuracy of routinely used H. pylori tests in atrophic gastritis.

METHODS

We compared 5 H. pylori diagnostic tests in 119 dyspeptic patients (28 males/91 females) with a mean age of 67 years (range 55-84). Patients with gastric cancer, peptic ulcer, previous gastric surgery, or those who have received eradication therapy were excluded. The following tests were performed: histology, rapid urease test (RUT), culture, 13C- urea breath tests (UBT), and H.pylori IgG/IgA antibody test (serology).

RESULTS

Atrophic gastritis was diagnosed in 26.1% of the patients; H. pylori was present in 87.1%. In the group with atrophy, the sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy were as follows: histology (100% for all parameters); UBT (96; 100; 100; 80; 97%); serology (96; 50; 93; 67; 90%); culture (96; 100; 100; 80; 97%); and RUT (78; 100; 100; 40; 81%), respectively.

CONCLUSIONS

Histology, UBT and culture were the three best tests for diagnosing H. pylori infection. We cannot recommend using serology as a single test in a case of atrophy, but it would be reasonable to combine serology with one of the above tests.

Changing patterns of serological testing for celiac disease in Latvia

BACKGROUND AND AIMS

A number of recent guidelines have discouraged the use of the old anti-gliadin tests for the detection of celiac disease; tissue transglutaminase IgA (tTGA) and anti-endomysial (EMA) tests are recommended instead. Our aim was to evaluate how the current recommendations have been applied in real practice. The secondary aim was to evaluate the positivity rates provided by different test types.

METHODS

We analyzed the number of celiac disease tests [anti-gliadin IgA (AGA), anti-gliadin IgG (AGG), tTGA and EMA] performed by the largest laboratory in Latvia. The analysis was performed on a yearly basis for the period between 2004 and 2009. Additionally, we analyzed the percentage of the positive test results for each of the tests.

RESULTS

The number of patients being tested for celiac disease constantly increased, with the average annual growth of 16.1%; this trend was similar both in children and in adults. The majority of patients (62.6%) were tested with anti-gliadin tests only; 27.7% were tested with either tTGA or EMA, while 9.7% were tested by a combination of the above groups. There was a substantial difference in the positivity rates of the different tests from 0.94% for EMA to 21.8% for AGG. Substantial differences were also present between various manufacturers' products.

CONCLUSION

The current guidelines and the published evidence on the proper use of serological tests for celiac disease have been slow to be applied in clinical practice; more intensive education campaigns and change in reimbursement systems could improve the situation. Nevertheless, more clinicians in Latvia are checking patients for celiac disease; this suggests an overall increased awareness.

Ratio between metastatic and examined lymph nodes (N ratio) may have low clinical utility in gastric cancer patients treated by limited lymphadenectomy: results from a single-center experience of 526 patients

BACKGROUND

The aim of this study was to evaluate the prognostic value of the ratio of metastatic to examined lymph nodes (N ratio) in gastric cancer patients who underwent limited lymphadenectomy and had a small number (< or =15) of analyzed nodes.

METHODS

The prognostic value of the actual AJCC/UICC pN staging system and the N ratio (0%, 1-25%, > 25%) were analyzed by means of univariate and multivariate analyses for 526 patients who underwent R0 resection for gastric adenocarcinoma at the Latvia Oncology Center.

RESULTS

The mean (SD) number of analyzed nodes was 5.6 (2.8). The number of positive nodes significantly increased with the number of analyzed nodes (p < 0.001). No significant differences in survival (p = 0.508) and risk of death (p = 0.224) were observed between pN1 and pN2 subsets. When the N ratio (1-25% vs. > 25%) was taken into account, a significant difference was demonstrated between pNR1 and pNR2 with respect to survival (p = 0.017) and risk of death (p = 0.012). Nonetheless, the joint allocation of the two classifications demonstrated that only a minority of patients (28 cases) belonged to the pNR1 subset and none of these belonged to the AJCC/UICC pN2 subset.

CONCLUSIONS

When a small number of lymph nodes are analyzed, the N ratio can discriminate patients better than TNM classification. However, because a small number of retrieved nodes produced only a small number of pNR1 patients, the N ratio classification cannot be justified for clinical use.

The validity of a biomarker method for indirect detection of gastric mucosal atrophy versus standard histopathology

BACKGROUND

Atrophy of the stomach mucosa is considered to be premalignant lesion for gastric cancer development; easy identification of this condition from a blood-sample would allow identifying the group of individuals at increased risk for cancer development.

AIMS

The objective of the current study was to validate a biomarker method (pepsinogen I/II ratio and gastrin-17) for indirect detection of atrophy of the stomach mucosa versus standard histopathology in Caucasian and Asian populations.

METHODS

Altogether, 241 patients aged 55 and above referred for upper endoscopy due to dyspeptic symptoms (125 from Latvia, 76 from Lithuania, and 40 from Taiwan) were enrolled. Pepsinogen I, pepsinogen II, gastrin-17 (the latter after stimulation with protein-rich meal) and IgG/IgA antibodies to Helicobacter pylori infection were determined by ELISA method; standard histopathology according to the updated Sydney classification read by two independent expert pathologists was used for the comparison.

RESULTS

Pepsinogen I/II ratio below 3 was well related to atrophy (moderate to severe) in the corpus part of the stomach (P < 0.0001) with 83.3% sensitivity and 87.1% specificity. Gastrin-17 below 5 pmol/L was related to atrophy in the antral part (P = 0.007) with 36.8% sensitivity and 86.5% specificity.

CONCLUSIONS

Decreased pepsinogen I/II ratio is a reliable marker for atrophy in the corpus, and may be recommended for identification of individuals with this type of atrophy. The utility of gastrin-17 for the detection of atrophy in the antral part of the stomach still requires further evaluation due to the low sensitivity.

Molecular characterisation and expression analysis of SEREX-defined antigen NUCB2 in gastric epithelium, gastritis and gastric cancer

NUCB2 is an EF-hand Ca2+ binding protein that has been implicated in various physiological processes like calcium homeostasis, hypothalamic regulation of feeding and TNF receptor shedding. In our previous study we identified NUCB2 as a potential tumour antigen eliciting autoantibody responses in 5.4% of gastric cancer patients but not in the healthy individuals.The current study aimed to elucidate the molecular mechanism underlying NUCB2 immunogenicity and to gain an insight into the physiological functions of NUCB2 in the stomach. mRNA expression analysis demonstrated that NUCB2 is ubiquitously expressed in normal tissues, including lymphoid tissues, and downregulated in gastric tumours when compared with the adjacent relatively normal stomach tissues.The search for molecular alterations resulted in the identification of novel mRNA variants transcribed from an alternative promoter and expressed predominantly in gastric cancers. Western blot analysis demonstrated that the protein levels correspond to mRNA levels and revealed that NUCB2 is phosphorylated in gastric mucosa. Furthermore, a 55 kDa isoform,generated presumably by yet an unidentified post-translational modification was detected in gastric tumours and AGS gastric cancer cells but was absent in the relatively normal gastric mucosa and thereby might have served as a trigger for the immune response against NUCB2. Staining of stomach tissue microarray with anti-NUCB2 antibody revealed that it is expressed in the secretory granules of chief cells and in the cytoplasm of parietal cells in the functioning gastric glands which are lost in atrophic glands and tumour cells. Hence we propose that NUCB2 may be implicated in gastric secretion by establishing an agonist-releasable Ca2+ store in ER or Golgi apparatus, signalling via heterotrimeric Galpha proteins and/or mediating the exocytosis of the secretory granules.

Molecular characterisation and expression analysis of SEREX-defined antigen NUCB2 in gastric epithelium, gastritis and gastric cancer

NUCB2 is an EF-hand Ca²⁺ binding protein that has been implicated in various physiological processes like calcium homeostasis, hypothalamic regulation of feeding and TNF receptor shedding. In our previous study we identified NUCB2 as a potential tumour antigen eliciting autoantibody responses in 5.4% of gastric cancer patients but not in the healthy individuals. The current study aimed to elucidate the molecular mechanism underlying NUCB2 immunogenicity and to gain an insight into the physiological functions of NUCB2 in the stomach. mRNA expression analysis demonstrated that NUCB2 is ubiquitously expressed in normal tissues, including lymphoid tissues, and downregulated in gastric tumours when compared with the adjacent relatively normal stomach tissues. The search for molecular alterations resulted in the identification of novel mRNA variants transcribed from an alternative promoter and expressed predominantly in gastric cancers. Western blot analysis demonstrated that the protein levels correspond to mRNA levels and revealed that NUCB2 is phosphorylated in gastric mucosa. Furthermore, a 55 kDa isoform, generated presumably by yet an unidentified post-translational modification was detected in gastric tumours and AGS gastric cancer cells but was absent in the relatively normal gastric mucosa and thereby might have served as a trigger for the immune response against NUCB2. Staining of stomach tissue microarray with anti-NUCB2 antibody revealed that it is expressed in the secretory granules of chief cells and in the cytoplasm of parietal cells in the functioning gastric glands which are lost in atrophic glands and tumour cells. Hence we propose that NUCB2 may be implicated in gastric secretion by establishing an agonist-releasable Ca²⁺ store in ER or Golgi apparatus, signalling via heterotrimeric G_α proteins and/or mediating the exocytosis of the secretory granules.

Surgical treatment of gastric cancer in Latvia: results of centralized experience

BACKGROUND

Although the mortality for gastric cancer is decreasing in Western Europe and United States, it still remains high in Eastern Europe. This study was aimed at evaluating short- and long-term results of surgical treatment of gastric cancer performed in Latvia Oncology Center.

METHODS

Retrospectively collected data from 461 patients who underwent gastrectomy with curative intent in Latvia Oncology Center from January 2001 to December 2005 were analyzed statistically.

RESULTS

An average (range) of 92.2 (81-102) R0-R1 gastrectomies was performed each year. Post-operative complications occurred in 75 patients (16.3%); in-hospital mortality was 3.3%. The overall 5-year survival was 50.8%. In 444 cases (96.3%) there was histopathologic confirmation of R0-resection with a 5-year survival of 52.5% (P<0.001). Considering pT category, 5-year survival was 88.6% for pT1 patients, 65% for pT2, 42.3% for pT3 and 27% for pT4 (P<0.001). Considering pN category, 5-year survival was 67% for pN0 patients, 30% for pN1 and 29% for pN2-3 (P<0.001).

CONCLUSIONS

Clinico-pathologic characteristics of patients who underwent resection with curative intent are comparable to other Western experiences. Short- as well as long-term results are also similar if not for pN+ patients where no difference between pN1 and pN2 cases was observed.

Helicobacter pylori and non-malignant diseases

In 2007 Helicobacter pylori research continued to deal with some controversies raised in the last decade. The main problems remain unsolved: peptic ulcer disease negative for H. pylori, synergism of H. pylori infection and aspirin and other nonsteroidal anti-inflammatory drugs or cyclooxygenase 2 specific inhibitors, the role of H. pylori eradication in uninvestigated and nonulcer dyspepsia, and the possible protective effect of H. pylori infection against gastroesophageal reflux disease and its complications such as Barrett's esophagus and adenocarcinoma. The incidence and prevalence of peptic ulcer disease as well as ulcer-related mortality are continuing to decline all over the world. The increasing consumption of anti-inflammatory and antisecretory drugs was not found to change the trend over the last period and therefore H. pylori was considered the key factor in causing ulcer-related mortality. Some progress has been achieved in understanding H. pylori-induced immunological processes, and attack mechanisms, as well as specific pathogenesis in uremic and cirrhotic patients. There is still a lot to learn about the bacterium and host factors related to H. pylori infection and its complications.

Should we screen for Helicobacter pylori to prevent gastric cancer?

Although the strategy for Helicobacter pylori infection management is well defined and quite well followed in a number of situations, including peptic ulcer disease, the issue of H. pylori screening and eradication in the general population still remains. The following debate attempts to find the answer of whether or not H. pylori screening should be performed in the asymptomatic population for preventing gastric cancer. As yet, there is no final evidence-based consensus about the need to screen for H. pylori in order to decrease the incidence of gastric cancer.

Precancerous gastric conditions in high Helicobacter pylori prevalence areas: comparison between Eastern European (Lithuanian, Latvian) and Asian (Taiwanese) patients

The aim of the study was to compare the prevalence and severity of precancerous condition--gastric atrophy and intestinal metaplasia (IM) between Eastern European (Lithuania and Latvia) and Asian (Taiwan) countries in population older than 55 years.

METHODS

Patients aged 55 years and older, referred for upper endoscopy due to dyspeptic symptoms, were included in the study. Gastric biopsies were histological investigated according modified Sydney classification. Helicobacter pylori (H. pylori) was detected if any two of three methods (urease test, histology, and serology) were positive.

RESULTS

Overall 322 patients included: 52 from Taiwan (TW), 171 from Latvia (LV) and 99 from Lithuania (LT). There were 227 (70%) females and 95 (30%) males. The mean age of TW patients was significantly lower (61.0+/-5.8 years), than of LV (68.1+/-7.3 years) and LT (66.5+/-7.5 years) patients. H. pylori was established in 224 (69.6%) patients. H. pylori positivity was established in 43 (82.7%) TW patients, in 112 (65.5%) LV patients, and in 69 (69.7%) LT patients (P>0.05). In H. pylori-infected patients, any atrophy either in the corpus or in the antrum of the stomach was detected in 26 (60.5%) TW patients, in 40 (35.7%) LV patients, and in 36 (52.2%) LT patients (between TW and LV patients P<0.005). Severe atrophy (grade 2 or 3) detected in 8 (18.6%) TW patients, in 17 (15.2%) LV patients, and in 18 (26.1%) LT patients (P>0.05). Intestinal metaplasia was detected in 22 (51.2%) TW patients, in 37 (33.0%) LV patients and in 31 (44.9%) LT patients among countries (P>0.05). There were no significant differences in proportions of different degrees of both atrophy and intestinal metaplasia among countries. Intestinal metaplasia was found in 79 (77.5%) of 102 patients with any degree of atrophy and in 11 (9.0%) of 122 patients without atrophy (P<0.0001). We found strong statistically significant correlations between atrophy and intestinal metaplasia in antrum (r=0.89), P<0.01, and corpus (r= 0.73), P<0.01.

CONCLUSIONS

The prevalence of H. pylori in the elderly population is still high in LT, LV, and TW. There are no significant differences in prevalence of gastric atrophy and intestinal metaplasia among TW, LT, and LV. There is a strong correlation between gastric atrophy and intestinal metaplasia.

Prevalence of childhood asthma, rhinitis and eczema in Scandinavia and Eastern Europe

There is evidence that the prevalence of allergies and asthma differs between populations in western and eastern Europe. This study investigated the prevalence of wheezing, rhinitis and eczema among schoolchildren in urban and rural areas of Scandinavia and the formerly socialist countries of Eastern Europe. A total of 79,000 children from two age groups (13-14 yrs and 6-7 yrs) in 18 study centres responded to a questionnaire within the International Study of Asthma and Allergy in Children (ISAAC). The 12 month period prevalence of symptoms of asthma, allergic rhinoconjunctivitis and atopic eczema was calculated. The prevalence of wheezing among the 13-14 yr old children was 11.2-19.7% in Finland and Sweden, 7.6-8.5% in Estonia, Latvia and Poland and 2.6-5.9% in Albania, Romania, Russia, Georgia and Uzbekistan (except Samarkand). The prevalence of itching eyes and flexural dermatitis varied in a similar manner between the three regions. The regional differences were less pronounced among the 6-7 yr old children in the seven participating centres. The highest prevalence of rhinitis was recorded in April-July in Scandinavia and during the winter months in the other countries. The prevalence of atopy-related disorders was higher in Scandinavia than in Estonia, Latvia and Poland, which in turn had a higher prevalence than five other countries of eastern Europe with a culture less similar to western Europe. This supports the hypothesis that "Western life style" is associated with a high prevalence of childhood allergy.

High consumption of fatty fish from the Baltic Sea is associated with changes in human lymphocyte subset levels

Fatty fish from the Baltic Sea accumulate immunotoxic persistent organochlorine compounds. In a previous study we found inverse correlations between such fish consumption and natural killer (NK) cell levels in a Swedish population. The present study concerns 68 Latvian subjects with high, low or intermediate fish consumption. High fish consumption correlated positively with B cell levels and CD4+/CD8+ ratios, but negatively with levels of cytotoxic (CD8+) T cells. Furthermore, NK cell levels correlated inversely with plasma selenium, one of several strong correlates with fish intake. A high fish diet includes a set of possible immunomodulating agents. It is presently not possible to pinpoint the cause for the observed subset deviations or to establish their possible biological importance.