Jin-Su Jun

Proteomic Analysis of the Sarcosine-Insoluble Outer Membrane Fraction of Helicobacter pylori Strain 26695

Helicobacter pylori causes gastroduodenal disease, which is mediated in part by its outer membrane proteins (OMPs). To identify OMPs of H. pylori strain 26695, we performed a proteomic analysis. A sarcosine-insoluble outer membrane fraction was resolved by two-dimensional electrophoresis with immobilized pH gradient strips. Most of the protein spots, with molecular masses of 10 to 100 kDa, were visible on the gel in the alkaline pI regions (6.0 to 10.0). The proteome of the OMPs was analyzed by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. Of the 80 protein spots processed, 62 spots were identified; they represented 35 genes, including 16 kinds of OMP. Moreover, we identified 9 immunoreactive proteins by immunoblot analysis. This study contributes to the characterization of the H. pylori strain 26695 proteome and may help to further elucidate the biological function of H. pylori OMPs and the pathogenesis of H. pylori infection.

Changes in the Age-Specific Prevalence of Hepatitis A Virus Antibodies: A 10-Year Cohort Study in Jinju, South Korea

The changing patterns in seroprevalence rates of hepatitis A virus antibodies among children and adolescents from 1988 to 1997 reflect the cohort effects that occurred over 10 years in South Korea. Our results suggest that the majority of adolescents and young adults are at risk of symptomatic hepatitis A virus infection and morbidity.

Quantitative analysis of representative proteome components and clustering of Helicobacter pylori clinical strains.

Background:  Several Helicobacter pylori proteins have been reported to be associated with severe symptoms of gastric disease. However, expression levels of most of these disease‐associated proteins require further evaluation in order to clarify their relationships with gastric disease patterns. Representative proteome components of 71 clinical isolates of H. pylori were analyzed quantitatively to determine whether the protein expression levels were associated with gastric diseases and to cluster clinical isolates.

Changing pattern of antibiotic resistance of Helicobacter pylori in children during 20 years in Jinju, South Korea

The antimicrobial resistance capability of Helicobacter pylori is one of the critical factors in the failure to treat this pathogen. The purpose of this study was to investigate the changing pattern of primary antibiotic resistance rates in children in the southern central part of South Korea from 1990 to 2009.

Influencing Factors to Results of the Urease Test: Age, Sampling Site, Histopathologic Findings, and Density of Helicobacter pylori.

Purpose We investigated the positivity rate and the time period to the positive color change of the urease test in children and adults and assessed the correlation of the urease test to histopathologic findings. Methods From 1995 to 2000, endoscopic biopsies of the antrum and body were collected from 811 children and 224 adults and subjected to urease tests and histopathology. Results The positivity rate of the urease test was 49.4% for 0-4 years, 48.4% for 5-9 years, 47.3% for 10-15 years, and 62.5% for 20-29 years in the antrum. The positivity rate was 85.1% in 0-4 years, 82.3% in 5-9 years, 74.7% in 10-15 years, and 74.1% in 20-29 years for the body. In the antrum, the highest positivity rate was <1 hour for the group aged 10-29 years and 6-24 hours in the group <10 years old (p<0.0001). In the body, the highest positivity rate was <1 hour in adults and 6-24 hours in children (p<0.0001). The proportions of the positive reactions within 1 hour were similar for the antrum and the body. In the cases of more severe chronic gastritis, active gastritis, and Helicobacter pylori infiltration, a positive urease test reaction occurred more quickly (p<0.0001). Conclusion There were significant differences in urease tests according to age and sampling site. The discrepancy between the antrum and the body was greater in younger children. These results might be related to the low density and patchy distribution of bacteria in children and in the body.

Immunohistochemical Expressions of MUC2, MUC5AC, and MUC6 in Normal, Helicobacter pylori Infected and Metaplastic Gastric Mucosa of Children and Adolescents

The aim of this study was to investigate expression of gastric mucins in children and adolescents and to assess their relations with age and Helicobacter pylori (H. pylori) infection.

Development of an ELISA for Quantitative Detection of Immunoglobulin G (IgG) and IgA Antibodies to Helicobacter pylori for Use in Korean Patients with H. pylori-Associated Diseases

Background/Aims We aimed to develop a quantitative enzyme-linked immunosorbent assay (ELISA) using whole-cell lysates of Helicobacter pylori 51 and to investigate its validity. Methods Data from 300 plates were obtained by two different operators. Standard sera were used to make a standard curve to analyze the quantity of anti-H. pylori immunoglobulin G (IgG) and IgA antibody. We obtained reproducible data with fewer dilutions of samples by the addition of serially diluted standard serum to each ELISA plate. To evaluate the validity of this ELISA, the 114 H. pylori-positive and -negative subjects were stratified into four age groups, i.e., 0 to 4, 5 to 9, 10 to 15, and 20 to 29 years, before testing. Results The mean IgG-antibody titers in H. pylori-positive and -negative subjects were 1,766.4 IU/mL and 654.3 IU/mL (p<0.001). The mean IgA-antibody titers in H. pylori-positive and -negative subjects were 350.1 IU/mL and 193.5 IU/mL (p<0.001). Anti-H. pylori IgG and IgA titers in the four age groups were higher in H. pylori-positive subjects than in H. pylori-negative subjects (p<0.05). Conclusions Using the current ELISA based on whole-cell lysates of H. pylori 51, reliable anti-H. pylori antibody titers were obtained regardless of the subjects age.

Changes in anti-group a rotavirus antibody seroprevalence and levels in the Western Gyeongnam province of Korea over 16 years.

To observe how anti-group A rotavirus antibody seropositivity rates and levels have changed in the western region of Gyeongnam Province, 2,030 serum samples collected at four collection periods (1989-1990, 1994-1995, 1999-2000, and 2004-2005) were tested by Enzyme-Linked Immunosorbent Assay for IgG, and IgA antibodies reacting to recombinant VP6 protein. The seroprevalences exhibit no regular patterns over a 16-yr period. For all four collection periods, the anti-rVP6 IgG levels rose steadily during the first 5 months of life, after which they remained high. However, the 2-9 yr and 10-39 yr groups had significantly higher IgG levels in 1999-2000 and 2004-2005, respectively, than in the other collection periods. The 1-5 mo, 40- ≥ 60 yr, and 4-29 yr groups had significantly higher IgA levels in 1989-1990, 1999-2000, and 2004-2005, respectively. The 4 yr (25.0%), 5-9 yr (18.8%), 10-14 yr (41.1%), 20-29 yr (35.0%), and 30-39 yr (20.0%) groups in 2004-2005 had significant higher IgA seropositivity rate compared to the other three collection periods. These observations suggest that in the western region of Gyeongnam Province since the late 1990s, rotavirus reinfection has occurred more frequently than previously, with all ages being at risk.

Gastric Autoantigenic Proteins in Helicobacter Pylori Infection

Purpose This study tried to identify novel gastric autoimmune antigens that might be involved in aggravating the atrophic gastritis among patients with Helicobacter pylori infection using two-dimensional immunoblotting analysis. Materials and Methods Proteins from gastric mucosal antrectomy specimens and AGS cells (gastric adenocarcinoma cell lines derived from a Caucasian patient who had received no prior therapy) were 2-dimensionally immunoblotted separately with a pool of 300 sera from H. pylroi-infected patients at Gyeongsang National University Hospital. Results Thirty-eight autoantigenic proteins including alcohol dehydrogenase [NADP+], alpha enolase, gastrokine-1, gastric triacylglycerol lipase, heat shock 70 kDa protein 1, and peroxiredoxin-2 were identified in the gastric mucosal tissue. Fourteen autoantigenic proteins including programmed cell death 6-interacting protein, serum albumin and T-complex protein 1 subunit gamma were identified in the AGS cells. Albumin, alpha-enolase, annexin A3, cytoplasmic actin 1, heat shock cognate 71 kDa protein and leukocyte elastase inhibitor were commonly observed autoantigenic proteins in both gastric mucosal tissue and AGS cells. Alpha-enolase, glutathione S-transferase P, heat shock cognate 71 kDa protein, heat shock 70 kDa protein 1, human mitochondrial adenosine triphosphate synthase (ATP) subunit beta, mitochondrial 60 kDa heat shock protein, peroxiredoxin-2, 78 kDa glucose-regulated protein precursor, tyrosine-protein phosphatase non-receptor type 11 and Tryptophan-Aspartic acid (WD) repeat-containing protein 1 showed 60% or higher amino acid positivity. Conclusion These newly identified gastric autoimmune antigens might be useful in the control and prevention of gastroduodenal disorders, and might be valuable in breaking the vicious circle that exists in gastroduodenal disorders if their pathophysiological roles could be understood in the progress of chronic atrophic gastritis, gastroduodenal ulcers, intestinal metaplasia, and gastric carcinogenesis.

Recovery of Helicobacter pylori from Gastric Tissue Cryopreserved for More than 10 Years

Dear Editor, At present, there is a great deal of research being conducted on Helicobacter pylori and the diseases with which it is associated. In particular, H. pylori in gastric tissue specimens is frequently used for studies on the pathogenic factors, antibiotic resistance, transmission, and disease associations of this bacterium. However, compared with other intestinal bacteria, H. pylori is a difficult organism to work with as it is fragile at room and low temperatures [1]. For the long-term storage of H. pylori, several transport media and several freezing methods have been described [2–4]. In particular, it has been shown that freezing with glycerol allows gastric biopsy specimens to be stored for a few weeks at 25 °C, and probably for several months at temperatures below 70 °C [5]. Another study has revealed that most strains of H. pylori can be stored for up to 1 year or longer at 70 °C or in liquid nitrogen [6]. However, a standard method for the long-term preservation of H. pylori is lacking. To address these issues, we retrieved gastric mucosal biopsies that were frozen with or without cryopreservatives more than 10 years ago and determined the frequencies with which the H. pylori bacteria therein could be cultured. In total, 44 cryopreserved gastric antrum mucosal biopsies from 29 children who underwent endoscopy in 1990 (one specimen each from 14 children) or 1992 (two specimens each from 15 children) at the Department of Pediatrics, Gyeongsang National University Hospital, were retrieved. All 14 specimens obtained in 1990 were deeply frozen in Eppendorf tubes with optimum cutting temperature (OCT) compound, which is an embedding medium composed of water-soluble glycols and resins that generates a convenient specimen matrix for cryostat sectioning at temperatures of 10 °C and below and which used to be used to cryopreserve tissues for histochemistry or the detection of a specific antigen. With regard to the specimens obtained in 1992, for each of the 15 patients, two gastric biopsy tissues were cryopreserved in Eppendorf tubes, one in OCT compound and one without OCT compound. All biopsy specimens were stored in a deep freezer at 70 °C. At the time of collection, all samples were positive upon urease testing within 1 hour. Moreover, all samples had been classified according to the histopathologic findings by using the Updated Sydney System. All biopsy specimens were donated by the National Biobank of Korea (Gyeongsang National University Hospital) after the Institutional Review Board reviewed the research protocols (GNUHIRB 2009007). The frozen gastric biopsies were thawed in fetal bovine serum or phosphate-buffered saline (PBS) solution and then cultured on Brucella agar base (Becton Dickinson, Heidelberg, Germany) containing 10% bovine serum, vancomycin (10 lg/mL), nalidixic acid (25 lg/mL), and amphotericin B (1 lg/mL). The plates were incubated overnight for 14 days at 37 °C under 5% O2, 10% CO2, and 85% N2 in a 100% humid atmosphere. Of the 29 patients, 17 were men (58.6%) and 12 were women (41.4%), and the median age was 11.8 years (range: 3.4–14.9 years). The histopathologic examinations performed after the biopsies were taken revealed that 25 of the 29 patients (86.2%) exhibited bacterial infiltration of the gastric antral mucosa. The recovery rates from OCT compound-cryopreserved tissues were 78.6% in 1990 and 26.7% in 1992 (Table 1), and the overall recovery rates from specimens that had been cryopreserved with OCT compound and without media were 51.7% (15/29) and 66.7% (10/15), respectively. When the 29 patients were divided according to whether H. pylori could be cultured from their samples, the culture-positive and culture-negative groups did not differ significantly in terms of histopathologic findings, age and sex distribution (p > .05). The 21 culturepositive patients consisted of 14 boys and seven girls whose median age was 12.0 years (range, 3.4– 14.1 years). H. pylori had been observed in the gastric