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Sample records for vacas prenhes previamente

  1. An Overview of Helicobacter pylori VacA Toxin Biology.

    PubMed

    Foegeding, Nora J; Caston, Rhonda R; McClain, Mark S; Ohi, Melanie D; Cover, Timothy L

    2016-01-01

    The VacA toxin secreted by Helicobacter pylori enhances the ability of the bacteria to colonize the stomach and contributes to the pathogenesis of gastric adenocarcinoma and peptic ulcer disease. The amino acid sequence and structure of VacA are unrelated to corresponding features of other known bacterial toxins. VacA is classified as a pore-forming toxin, and many of its effects on host cells are attributed to formation of channels in intracellular sites. The most extensively studied VacA activity is its capacity to stimulate vacuole formation, but the toxin has many additional effects on host cells. Multiple cell types are susceptible to VacA, including gastric epithelial cells, parietal cells, T cells, and other types of immune cells. This review focuses on the wide range of VacA actions that are detectable in vitro, as well as actions of VacA in vivo that are relevant for H. pylori colonization of the stomach and development of gastric disease. PMID:27271669

  2. An Overview of Helicobacter pylori VacA Toxin Biology

    PubMed Central

    Foegeding, Nora J.; Caston, Rhonda R.; McClain, Mark S.; Ohi, Melanie D.; Cover, Timothy L.

    2016-01-01

    The VacA toxin secreted by Helicobacter pylori enhances the ability of the bacteria to colonize the stomach and contributes to the pathogenesis of gastric adenocarcinoma and peptic ulcer disease. The amino acid sequence and structure of VacA are unrelated to corresponding features of other known bacterial toxins. VacA is classified as a pore-forming toxin, and many of its effects on host cells are attributed to formation of channels in intracellular sites. The most extensively studied VacA activity is its capacity to stimulate vacuole formation, but the toxin has many additional effects on host cells. Multiple cell types are susceptible to VacA, including gastric epithelial cells, parietal cells, T cells, and other types of immune cells. This review focuses on the wide range of VacA actions that are detectable in vitro, as well as actions of VacA in vivo that are relevant for H. pylori colonization of the stomach and development of gastric disease. PMID:27271669

  3. Relationship between vacA Types and Development of Gastroduodenal Diseases

    PubMed Central

    Thi Huyen Trang, Tran; Thanh Binh, Tran; Yamaoka, Yoshio

    2016-01-01

    The Helicobacter pylori vacuolating cytotoxin (VacA) is a secreted pore-forming toxin and a major virulence factor in the pathogenesis of H. pylori infection. While VacA is present in almost all strains, only some forms are toxigenic and pathogenic. While vacA and its genotypes are considered as markers of H. pylori-related diseases or disorders, the pathophysiological mechanisms of VacA and its genotypes remain controversial. This review outlines key findings of publications regarding vacA with emphasis on the relationship between vacA genotypes and the development of human disease. PMID:27294955

  4. Use of VacA as a Vaccine Antigen

    PubMed Central

    Moyat, Mati; Velin, Dominique

    2016-01-01

    One of the major toxins secreted by H. pylori is the Vacuolating cytotoxin A (VacA) named after its ability to induce the formation of “vacuole”-like membrane vesicles in the cytoplasm of gastric cells. VacA has been associated with the disruption of mitochondrial functions, stimulation of apoptosis, blockade of T cell proliferation and promotion of regulatory T cells, thereby making it a promising vaccine target. Immunity to bacterial virulence factors is well known to protect humans against bacterial infections; hence, detoxified VacA has been evaluated as a vaccine antigen. Our short review summarizes the pre-clinical and clinical data that have been published on the use of VacA in the development of the H. pylori vaccine. PMID:27338474

  5. New Insights into VacA Intoxication Mediated through Its Cell Surface Receptors

    PubMed Central

    Yahiro, Kinnosuke; Hirayama, Toshiya; Moss, Joel; Noda, Masatoshi

    2016-01-01

    Helicobacter pylori (H. pylori), a major cause of gastroduodenal diseases, produces VacA, a vacuolating cytotoxin associated with gastric inflammation and ulceration. The C-terminal domain of VacA plays a crucial role in receptor recognition on target cells. We have previously identified three proteins (i.e., RPTPα, RPTPβ, and LRP1) that serve as VacA receptors. These receptors contribute to the internalization of VacA into epithelial cells, activate signal transduction pathways, and contribute to cell death and gastric ulceration. In addition, other factors (e.g., CD18, sphingomyelin) have also been identified as cell-surface, VacA-binding proteins. Since we believe that, following interactions with its host cell receptors, VacA participates in events leading to disease, a better understanding of the cellular function of VacA receptors may provide valuable information regarding the mechanisms underlying the pleiotropic actions of VacA and the pathogenesis of H. pylori-mediated disease. In this review, we focus on VacA receptors and their role in events leading to cell damage. PMID:27187473

  6. New Insights into VacA Intoxication Mediated through Its Cell Surface Receptors.

    PubMed

    Yahiro, Kinnosuke; Hirayama, Toshiya; Moss, Joel; Noda, Masatoshi

    2016-01-01

    Helicobacter pylori (H. pylori), a major cause of gastroduodenal diseases, produces VacA, a vacuolating cytotoxin associated with gastric inflammation and ulceration. The C-terminal domain of VacA plays a crucial role in receptor recognition on target cells. We have previously identified three proteins (i.e., RPTPα, RPTPβ, and LRP1) that serve as VacA receptors. These receptors contribute to the internalization of VacA into epithelial cells, activate signal transduction pathways, and contribute to cell death and gastric ulceration. In addition, other factors (e.g., CD18, sphingomyelin) have also been identified as cell-surface, VacA-binding proteins. Since we believe that, following interactions with its host cell receptors, VacA participates in events leading to disease, a better understanding of the cellular function of VacA receptors may provide valuable information regarding the mechanisms underlying the pleiotropic actions of VacA and the pathogenesis of H. pylori-mediated disease. In this review, we focus on VacA receptors and their role in events leading to cell damage. PMID:27187473

  7. Helicobacter pylori vacA Genotypes in Chronic Gastritis and Gastric Carcinoma Patients from Macau, China

    PubMed Central

    Pinto-Ribeiro, Ines; Ferreira, Rui M.; Batalha, Sellma; Hlaing, Thazin; Wong, Sio In; Carneiro, Fatima; Figueiredo, Ceu

    2016-01-01

    Helicobacter pylori is the major triggering factor for gastric carcinoma, but only a small proportion of infected patients develop this disease. Differences in virulence observed among H. pylori strains, namely in the vacuolating cytotoxin vacA gene, may contribute to this discrepancy. Infection with vacA s1, i1 and m1 strains increases the risk for progression of gastric premalignant lesions and for gastric carcinoma. However, in East Asian countries most of the H. pylori strains are vacA s1, regardless of the patients’ clinical status, and the significance of the vacA i1 and m1 genotypes for gastric carcinoma in this geographic area remains to be fully elucidated. The aim of the present study was to investigate this relationship in 290 patients from Macau, China. Using very sensitive and accurate genotyping methods, we detected infection with vacA i1 and with vacA m1 strains in, respectively, 85.2% and 52.6% of the patients that were infected with single genotypes. The prevalence of cagA-positive strains was 87.5%. No significant associations were observed between vacA genotypes or cagA and gastric carcinoma. It is worth noting that 37.5% of the infected patients had coexistence of H. pylori strains with different vacA genotypes. Additional studies directed to other H. pylori virulence factors should be performed to identify high risk patients in East Asia. PMID:27164143

  8. Helicobacter pylori vacA Genotypes in Chronic Gastritis and Gastric Carcinoma Patients from Macau, China.

    PubMed

    Pinto-Ribeiro, Ines; Ferreira, Rui M; Batalha, Sellma; Hlaing, Thazin; Wong, Sio In; Carneiro, Fatima; Figueiredo, Ceu

    2016-01-01

    Helicobacter pylori is the major triggering factor for gastric carcinoma, but only a small proportion of infected patients develop this disease. Differences in virulence observed among H. pylori strains, namely in the vacuolating cytotoxin vacA gene, may contribute to this discrepancy. Infection with vacA s1, i1 and m1 strains increases the risk for progression of gastric premalignant lesions and for gastric carcinoma. However, in East Asian countries most of the H. pylori strains are vacA s1, regardless of the patients' clinical status, and the significance of the vacA i1 and m1 genotypes for gastric carcinoma in this geographic area remains to be fully elucidated. The aim of the present study was to investigate this relationship in 290 patients from Macau, China. Using very sensitive and accurate genotyping methods, we detected infection with vacA i1 and with vacA m1 strains in, respectively, 85.2% and 52.6% of the patients that were infected with single genotypes. The prevalence of cagA-positive strains was 87.5%. No significant associations were observed between vacA genotypes or cagA and gastric carcinoma. It is worth noting that 37.5% of the infected patients had coexistence of H. pylori strains with different vacA genotypes. Additional studies directed to other H. pylori virulence factors should be performed to identify high risk patients in East Asia. PMID:27164143

  9. VacA's Induction of VacA-Containing Vacuoles (VCVs) and Their Immunomodulatory Activities on Human T Cells.

    PubMed

    Utsch, Ciara; Haas, Rainer

    2016-01-01

    Vacuolating cytotoxin A (VacA) is a secreted pore-forming toxin and one of the major virulence factors of Helicobacter pylori (H. pylori), which actively supports the persistence and survival of the bacteria in the special ecological niche of the human stomach. H. pylori genomes harbor different allelic forms of the vacA gene, which translate into functionally distinct VacA toxin types. VacA internalizes into various cell types via membrane or specific receptor interactions finally forming acidic endocytic VacA-containing vacuoles (VCVs). In this review, we focus on different characteristics of VacA, its interaction with host cells, the formation and protein content of VCVs and their intracellular transport into human T cells, which finally leads to the immunosuppressive phenotype of VacA. Immunomodulatory activities of VacA on human T cells are discussed with a focus on T-cell proliferation and calcium signaling. PMID:27322323

  10. Functional association between the Helicobacter pylori virulence factors VacA and CagA.

    PubMed

    Argent, Richard H; Thomas, Rachael J; Letley, Darren P; Rittig, Michael G; Hardie, Kim R; Atherton, John C

    2008-02-01

    The Helicobacter pylori virulence factors CagA and VacA are implicated in the development of gastroduodenal diseases. Most strains possessing CagA also possess the more virulent vacuolating form of VacA. This study assessed the significance of possession of both virulence factors in terms of their effect on gastric epithelial cells, using a set of minimally passaged, isogenic VacA, CagA and CagE mutants in H. pylori strains 60190 and 84-183. The cagA and cagE mutants were found to significantly increase VacA-induced vacuolation of epithelial cells, and the vacA mutants significantly increased CagA-induced cellular elongations, compared with wild-type strains, indicating that CagA reduces vacuolation and VacA reduces hummingbird formation. Although epithelial cells incubated with the wild-type H. pylori strains may display both vacuolation and hummingbird formation, it was found that (i) hummingbird length was significantly reduced in vacuolated cells compared with those without vacuolation; (ii) the number of vacuoles was significantly reduced in vacuolated cells with hummingbird formation compared with those without hummingbirds; and (iii) cells displaying extensive vacuolation did not subsequently form hummingbirds and vice versa. VacA did not affect the phosphorylation of CagA. These data show that VacA and CagA downregulate each other's effects on epithelial cells, potentially allowing H. pylori interaction with cells whilst avoiding excessive cellular damage. PMID:18201978

  11. Dynamin is involved in human epithelial cell vacuolation caused by the Helicobacter pylori–produced cytotoxin VacA

    PubMed Central

    Suzuki, Junko; Ohnsihi, Hirohide; Shibata, Hiroshi; Wada, Akihiro; Hirayama, Toshiya; Iiri, Taroh; Ueda, Namiki; Kanamaru, Chiho; Tsuchida, Tomohiro; Mashima, Hirosato; Yasuda, Hiroshi; Fujita, Toshiro

    2001-01-01

    The Helicobacter pylori–produced cytotoxin VacA induces intracellular vacuolation. To elucidate the molecular mechanism of vacuole formation by VacA, we examined the participation of dynamin, a GTPase functioning in intracellular vesicle formation, in human HeLa cells. Immunocytochemistry revealed that endogenous dynamin was localized to vacuoles induced by VacA. In cells transiently transfected with a GTPase-defective (dominant-negative) dynamin mutant, VacA failed to induce vacuolation. In contrast, VacA did induce vacuolation in cells transiently transfected with wild-type dynamin. Furthermore, under VacA treatment, neutral red dye uptake, a parameter of VacA-induced vacuolation, was inhibited in cells stably transfected with the dominant-negative dynamin mutant. In contrast, uptake was markedly enhanced in cells stably transfected with wild-type dynamin. Moreover, VacA cytopathic effects on the viability of HeLa cells were inhibited in cells stably transfected with dominant-negative dynamin-1. Sequential immunocytochemical observation confirmed that expression of dominant-negative dynamin did not affect VacA attachment to or internalization into HeLa cells. We suggest that dynamin is involved in the intracellular vacuolation induced by VacA. PMID:11160160

  12. A Nonoligomerizing Mutant Form of Helicobacter pylori VacA Allows Structural Analysis of the p33 Domain.

    PubMed

    González-Rivera, Christian; Campbell, Anne M; Rutherford, Stacey A; Pyburn, Tasia M; Foegeding, Nora J; Barke, Theresa L; Spiller, Benjamin W; McClain, Mark S; Ohi, Melanie D; Lacy, D Borden; Cover, Timothy L

    2016-09-01

    Helicobacter pylori secretes a pore-forming VacA toxin that has structural features and activities substantially different from those of other known bacterial toxins. VacA can assemble into multiple types of water-soluble flower-shaped oligomeric structures, and most VacA activities are dependent on its capacity to oligomerize. The 88-kDa secreted VacA protein can undergo limited proteolysis to yield two domains, designated p33 and p55. The p33 domain is required for membrane channel formation and intracellular toxic activities, and the p55 domain has an important role in mediating VacA binding to cells. Previous studies showed that the p55 domain has a predominantly β-helical structure, but no structural data are available for the p33 domain. We report here the purification and analysis of a nonoligomerizing mutant form of VacA secreted by H. pylori The nonoligomerizing 88-kDa mutant protein retains the capacity to enter host cells but lacks detectable toxic activity. Analysis of crystals formed by the monomeric protein reveals that the β-helical structure of the p55 domain extends into the C-terminal portion of p33. Fitting the p88 structural model into an electron microscopy map of hexamers formed by wild-type VacA (predicted to be structurally similar to VacA membrane channels) reveals that p55 and the β-helical segment of p33 localize to peripheral arms but do not occupy the central region of the hexamers. We propose that the amino-terminal portion of p33 is unstructured when VacA is in a monomeric form and that it undergoes a conformational change during oligomer assembly. PMID:27382020

  13. vacA Genotype Status of Helicobacter pylori Isolated from Foods with Animal Origin.

    PubMed

    Saeidi, Elnaz; Sheikhshahrokh, Amirhossein

    2016-01-01

    According to controversial theories and results of studies, foods with animal origins play an important role in the transmission of H. pylori to human. The aim of this study was to determine the distribution of vacA genotypes of H. pylori, isolated from milk and meat samples of cow, sheep, goat, camel, and buffalo. Eight hundred and twenty raw milk and meat samples were collected from various parts of Iran. Samples were cultured and those found positive for H. pylori were analyzed for the presence of various genotypes of vacA gene. Out of 420 milk and 400 meat samples, 92 (21.90%) and 105 (26.25%) were positive for H. pylori, respectively. The most commonly detected genotypes in the vacA gene were s1a (86.80%), m1a (79.18%), s1b (69.54%), and m1b (63.45%) and detected combined genotypes were mostly m1as1a (68.52%), m1as1b (60.40%), m1bs1b (55.83%), and m1bs1a (53.29%). High presence of bacteria in the milk and meat samples of sheep represents that sheep may be the natural host of H. pylori. High presence of H. pylori strains in milk and meat samples similar to vacA genotypes in human being suggests that milk and meat samples could be the sources of bacteria for human. PMID:27088092

  14. vacA Genotype Status of Helicobacter pylori Isolated from Foods with Animal Origin

    PubMed Central

    Saeidi, Elnaz

    2016-01-01

    According to controversial theories and results of studies, foods with animal origins play an important role in the transmission of H. pylori to human. The aim of this study was to determine the distribution of vacA genotypes of H. pylori, isolated from milk and meat samples of cow, sheep, goat, camel, and buffalo. Eight hundred and twenty raw milk and meat samples were collected from various parts of Iran. Samples were cultured and those found positive for H. pylori were analyzed for the presence of various genotypes of vacA gene. Out of 420 milk and 400 meat samples, 92 (21.90%) and 105 (26.25%) were positive for H. pylori, respectively. The most commonly detected genotypes in the vacA gene were s1a (86.80%), m1a (79.18%), s1b (69.54%), and m1b (63.45%) and detected combined genotypes were mostly m1as1a (68.52%), m1as1b (60.40%), m1bs1b (55.83%), and m1bs1a (53.29%). High presence of bacteria in the milk and meat samples of sheep represents that sheep may be the natural host of H. pylori. High presence of H. pylori strains in milk and meat samples similar to vacA genotypes in human being suggests that milk and meat samples could be the sources of bacteria for human. PMID:27088092

  15. Vacuolating cytotoxin A (VacA) - A multi-talented pore-forming toxin from Helicobacter pylori.

    PubMed

    Junaid, Muhammad; Linn, Aung Khine; Javadi, Mohammad Bagher; Al-Gubare, Sarbast; Ali, Niaz; Katzenmeier, Gerd

    2016-08-01

    Helicobacter pylori is associated with severe and chronic diseases of the stomach and duodenum such as peptic ulcer, non-cardial adenocarcinoma and gastric lymphoma, making Helicobacter pylori the only bacterial pathogen which is known to cause cancer. The worldwide rate of incidence for these diseases is extremely high and it is estimated that about half of the world's population is infected with H. pylori. Among the bacterial virulence factors is the vacuolating cytotoxin A (VacA), which represents an important determinant of pathogenicity. Intensive characterization of VacA over the past years has provided insight into an ample variety of mechanisms contributing to host-pathogen interactions. The toxin is considered as an important target for ongoing research for several reasons: i) VacA displays unique features and structural properties and its mechanism of action is unrelated to any other known bacterial toxin; ii) the toxin is involved in disease progress and colonization by H. pylori of the stomach; iii) VacA is a potential and promising candidate for the inclusion as antigen in a vaccine directed against H. pylori and iv) the vacA gene is characterized by a high allelic diversity, and allelic variants contribute differently to the pathogenicity of H. pylori. Despite the accumulation of substantial data related to VacA over the past years, several aspects of VacA-related activity have been characterized only to a limited extent. The biologically most significant effect of VacA activity on host cells is the formation of membrane pores and the induction of vacuole formation. This review discusses recent findings and advances on structure-function relations of the H. pylori VacA toxin, in particular with a view to membrane channel formation, oligomerization, receptor binding and apoptosis. PMID:27105670

  16. What exists beyond cagA and vacA? Helicobacter pylori genes in gastric diseases

    PubMed Central

    da Costa, Débora Menezes; Pereira, Eliane dos Santos; Rabenhorst, Silvia Helena Barem

    2015-01-01

    Helicobacter pylori (H. pylori) infection is present in more than half the world’s population and has been associated with several gastric disorders, such as gastritis, peptic ulceration, and gastric adenocarcinoma. The clinical outcome of this infection depends on host and bacterial factors where H. pylori virulence genes seem to play a relevant role. Studies of cagA and vacA genes established that they were determining factors in gastric pathogenesis. However, there are gastric cancer cases that are cagA-negative. Several other virulence genes have been searched for, but these genes remain less well known that cagA and vacA. Thus, this review aimed to establish which genes have been suggested as potentially relevant virulence factors for H. pylori-associated gastrointestinal diseases. We focused on the cag-pathogenicity island, genes with adherence and motility functions, and iceA based on the relevance shown in several studies in the literature. PMID:26457016

  17. Non-invasive Genotyping of Helicobacter pylori cagA, vacA, and hopQ from Asymptomatic Children

    PubMed Central

    Sicinschi, Liviu A.; Correa, Pelayo; Bravo, Luis E.; Peek, Richard M.; Wilson, Keith T.; Loh, John T.; Yepez, Maria C.; Gold, Benjamin D.; Thompson, Dexter T.; Cover, Timothy L.; Schneider, Barbara G.

    2011-01-01

    Background H. pylori infection is usually acquired in childhood, but little is known about its natural history in asymptomatic children, primarily due to the paucity of non-invasive diagnostic methods. H. pylori strains harboring cagA and specific alleles of hopQ and vacA are associated with increased risk for gastric cancer. Many studies of H. pylori virulence markers in children have the bias that symptomatic subjects are selected for endoscopy, and these children may harbor the most virulent strains. Our aim: to genotype cagA, hopQ and vacA alleles in stool DNA samples of healthy Colombian children residing in an area with high incidence of gastric cancer, in order to avoid selection bias resulting from endoscopy. Methods H. pylori status of 86 asymptomatic children was assessed by 13C-Urea Breath Test (UBT) and PCR. H. pylori 16S rRNA, cagA, hopQ and vacA genes were amplified from stool DNA samples and sequenced. Results UBT was positive in 69 (80.2%) of 86 children; in stool DNA analysis, 78.3% were positive by 16S rRNA PCR. cagA, vacA and hopQ were detected in 66.1%, 84.6%, and 72.3% of stool DNA samples from 16S rRNA positive children. Of the children's DNA samples which revealed vacA and hopQ alleles, 91.7% showed vacA s1 and 73.7% showed type I hopQ. Type I hopQ alleles were associated with cagA-positivity and vacA s1 genotypes (P<0.0001). Conclusions Using stool DNA samples, virulence markers of H. pylori were successfully genotyped in a high percentage of the asymptomatic infected children, revealing a high prevalence of genotypes associated with virulence. Type I hopQ alleles were associated with the presence of cagA and the vacA s1 genotype. PMID:22404439

  18. Heterogeneity in the Helicobacter pylori vacA and cagA genes: association with gastroduodenal disease in South Africa?

    PubMed Central

    Kidd, M; Lastovica, A; Atherton, J; Louw, J

    1999-01-01

    BACKGROUND—Helicobacter pylori infection is universally associated with gastritis, but only sometimes with clinically significant disease. Candidate virulence markers seem to be useful in identifying the pathogenic infections in some populations.
AIMS—To investigate the association between putative virulence markers and disease in an African population.
METHODS—Fifty nine H pylori strains isolated from dyspeptic patients (11 with peptic ulceration, eight with gastric adenocarcinoma, and 28 with no pathology other than gastritis) were studied for differences in the genes vacA and cagA.
RESULTS—Forty seven (80%) of 59 strains had the vacA signal sequence genotype s1 (one s1a, 46 s1b) and 12 (20%) had subtype s2. vacA mid-region analysis revealed that 40 (68%) strains were vacA m1 and 19 (32%) were m2. All 14 strains from patients with peptic ulceration were vacA s1, in contrast to 23 (66%) of 35 strains from patients with gastritis alone (p<0.01). vacA s2 was found exclusively in patients with gastritis alone (p<0.01). All strains isolated from patients with gastric adenocarcinoma were s1b/m1 (p<0.005 versus gastritis alone). cagA was detectable in 56 (95%) of 59 isolates. Strains from patients with peptic ulceration (12/13 versus 19/30 with gastritis alone, p=0.05) had the shortest fragment length in the 3' region of cagA, while 4/10 strains from patients with gastric cancer had the longest fragment length in this region (p<0.02 versus gastritis alone).
CONCLUSION—In this study, the vacA s1 genotype, and fragment length of the 3' region of cagA identified isolates associated with significant clinical disease. The vacA s1bm1 genotype seems to be strongly associated with gastric cancer.


Keywords: adenocarcinoma; cagA; Helicobacter pylori; peptic ulceration; South Africa; vacuolating cytotoxin PMID:10486355

  19. Characterization of Helicobacter pylori cagA and vacA Genotypes among Alaskans and Their Correlation with Clinical Disease▿

    PubMed Central

    Miernyk, Karen; Morris, Julie; Bruden, Dana; McMahon, Brian; Hurlburt, Debby; Sacco, Frank; Parkinson, Alan; Hennessy, Thomas; Bruce, Michael

    2011-01-01

    Helicobacter pylori infection is common in Alaska. The development of severe H. pylori disease is partially determined by the virulence of the infecting strain. Here we present vacA and cagA genotype data for H. pylori strains isolated from Alaskans and their correlation with clinical disease. We enrolled patients scheduled for esophagogastroduodenoscopy and positive for H. pylori infection. Gastric biopsy specimens from the stomach antrum and fundus were cultured. We performed PCR analysis of the H. pylori vacA gene and for the presence of the cagA gene and cagA empty site. We genotyped 515 H. pylori samples from 220 Native and 66 non-Native Alaskans. We detected the cagA gene in 242/286 (85%) persons; of 222 strains that could be subtyped, 95% (212) were non-Asian cagA and 3% (6) were East Asian cagA. After removing mixed infections (n = 17), 83% of H. pylori strains had either the vacA s1m1 (120/269) or s2m2 (103/269) genotype. Sixty-six percent (68/103) of H. pylori strains with the vacA s2m2 genotype also contained the cagA gene. Infection with an H. pylori strain having the cagA gene or vacA s1m1 genotype (compared with s1m2 and s2m2) was associated with a decreased risk of esophagitis (P = 0.003 and 0.0003, respectively). Infection with an H. pylori strain having the vacA s1m1 genotype (compared with s1m2 and s2m2) was associated with an increased risk of peptic ulcer disease (PUD) (P = 0.003). The majority of H. pylori strains in this study carried the non-Asian cagA gene and either the vacA s1m1 or s2m2 genotype. A majority of H. pylori strains with the vacA s2m2 genotype also contained the cagA gene. There was an association of H. pylori genotype with esophagitis and PUD. PMID:21752979

  20. Prevalence and correlation with clinical diseases of Helicobacter pylori cagA and vacA genotype among gastric patients from Northeast China.

    PubMed

    Aziz, Faisal; Chen, Xin; Yang, Xuesong; Yan, Qiu

    2014-01-01

    Helicobacter pylori vacA and cagA genes have significant genetic heterogenicity, resulting in different clinical outcomes. Northeast part of China has reported high prevalence of H. pylori infections and gastric cancer. Hence, we investigated the H. pylori cagA and vacA genotypes with clinical outcomes in Northeast China. Gastric tissue samples (n = 169), chronic gastritis (GIs), gastric ulcer (GU), and gastric cancer (GC) were analysed for 16S rRNA ureA, cagA, and cagA genotypes by PCR. A total of 141 (84%) cases were found positive for H. pylori by 16S rRNA and ureA. GC showed high H. pylori infection (93%) compared with GIs (72%) and GU (84%). The vacAs1am1 was highly found in GC (40%) and GU (36%), vacAs1am2 in GIs (33%), vacAs1bm1 (14%) and vacAs1bm2 (8%) in GU cases, and s2m1 in normal cases (33%), while vacAs1cm1 showed low frequency in GIs (2%) and GU (3%) and GC showed negative result. The East-Asian cagA strain was highly observed in GC (43%), as compared to GIs (41%) and GU (20%). The East-Asian cagA/vacAs1am1 was significantly higher in GC (23%) than in GU (22%) and GIs (145) patients. The East-Asian type cagA with vacAs1a and vacAm1 is the most predominant genotype in H. pylori strains of Northeast China. PMID:24949419

  1. Association between cagA and vacA genotypes and pathogenesis in a Helicobacter pylori infected population from South-eastern Sweden

    PubMed Central

    2012-01-01

    Background Chronic gastritis, peptic ulcer disease, and gastric cancer have been shown to be related to infection with Helicobacter pylori (H. pylori). Two major virulence factors of H. pylori, CagA and VacA, have been associated with these sequelae of the infection. In this study, total DNA was isolated from gastric biopsy specimens to assess the cagA and vacA genotypes. Results Variations in H. pylori cagA EPIYA motifs and the mosaic structure of vacA s/m/i/d regions were analysed in 155 H. pylori-positive gastric biopsies from 71 individuals using PCR and sequencing. Analysis of a possible association between cagA and vacA genotypes and gastroduodenal pathogenesis was made by logistic regression analysis. We found that H. pylori strains with variation in the number of cagA EPIYA motif variants present in the same biopsy correlated with peptic ulcer, while occurrence of two or more EPIYA-C motifs was associated with atrophy in the gastric mucosa. No statistically significant relation between vacA genotypes and gastroduodenal pathogenesis was observed. Conclusions The results of this study indicate that cagA genotypes may be important determinants in the development of gastroduodenal sequelae of H. pylori infection. In contrast to other studies, vacA genotypes were not related to disease progression or outcome. In order to fully understand the relations between cagA, vacA and gastroduodenal pathogenesis, the mechanisms by which CagA and VacA act and interact need to be further investigated. PMID:22747681

  2. Role of vacuolating cytotoxin VacA and cytotoxin-associated antigen CagA of Helicobacter pylori in the progression of gastric cancer.

    PubMed

    Ki, Mi-Ran; Hwang, Meeyul; Kim, Ah-Young; Lee, Eun-Mi; Lee, Eun-Joo; Lee, Myeong-Mi; Sung, Soo-Eun; Kim, Sang-Hyeob; Lee, Hye Seung; Jeong, Kyu-Shik

    2014-11-01

    Helicobacter (H.) pylori strains that express the cagA and s1a vacA genes are associated with an increased risk for gastric cancer. Here, we examined the association between the products of these virulence genes with the development of gastric cancer by immunohistochemical staining of gastric biopsy specimens taken from 208 routine gastroscopies and 43 gastric cancer patients. The correlation was analyzed by multivariate logistic regression. CagA and VacA expressions in gastric mucosa were significantly associated with chronic gastritis (CG) and intestinal metaplasia (IM), respectively, accompanying CG independent of age. The association of CagA expression with IM accompanying CG was increased in patients over 50-year old (p < 0.01) and that of VacA with CG was significant in patients younger than 50 year (p < 0.05). VacA and CagA were associated with mild IM incidence (p = 0.025 and p = 0.076, respectively) but not advanced IM. In the 43 gastric cancer patients, positivity for VacA was significantly higher in cases of CG and IM than carcinoma (p = 0.042), while that for CagA was slightly higher for individuals with carcinoma than those with CG and IM. These results indicate that CagA and VacA are critical factors for inducing CG and the subsequent progression of IM from CG with an increasing age. PMID:25038872

  3. Distinct Diversity of vacA, cagA, and cagE Genes of Helicobacter pylori Associated with Peptic Ulcer in Japan

    PubMed Central

    Yamazaki, Shiho; Yamakawa, Akiyo; Okuda, Tomoyuki; Ohtani, Masahiro; Suto, Hiroyuki; Ito, Yoshiyuki; Yamazaki, Yukinao; Keida, Yoshihide; Higashi, Hideaki; Hatakeyama, Masanori; Azuma, Takeshi

    2005-01-01

    Colonization of the stomach mucosa by Helicobacter pylori is a major cause of acute and chronic gastric pathologies in humans. Several H. pylori virulence genes that may play a role in its pathogenicity have been identified. The most important determinants are vacA and cagA in the cag pathogenicity island (cagPAI) genes. In the present study, to consider the association of molecular genetics between vacA and the cagPAI regarding clinical outcome, we selected H. pylori strains with various genotypes of vacA in Japan and sequenced full-length vacA, cagA, and cagE genes. Sequencing of vacA and cagA genes revealed variable size, whereas the cagE gene was well conserved among strains. Each of the phylogenetic trees based on the deduced amino acid sequences of VacA, CagA, and CagE indicated that all three proteins were divided into two major groups, a Western group and an East Asian group, and the distributions of isolates exhibited similar patterns among the three proteins. The strains with s2 and s1a/m1a vacA genotypes and the Western-type 3′ region cagA genotype were classified into the Western group, and the strains with the s1c/m1b vacA genotype and the East Asian-type 3′ cagA genotype were included in the East Asian group. In addition, the prevalence of infection with the Western group strain was significantly higher in patients with peptic ulcer (90.0%, 9/10) than in patients with chronic gastritis (22.7%, 5/22) (χ2 = 12.64, P = 0.00057). These data suggest that the molecular genetics of vacA and cagPAI are associated and that the Western group with vacA and cagPAI genes is associated with peptic ulcer disease. PMID:16081930

  4. Distinct diversity of vacA, cagA, and cagE genes of Helicobacter pylori associated with peptic ulcer in Japan.

    PubMed

    Yamazaki, Shiho; Yamakawa, Akiyo; Okuda, Tomoyuki; Ohtani, Masahiro; Suto, Hiroyuki; Ito, Yoshiyuki; Yamazaki, Yukinao; Keida, Yoshihide; Higashi, Hideaki; Hatakeyama, Masanori; Azuma, Takeshi

    2005-08-01

    Colonization of the stomach mucosa by Helicobacter pylori is a major cause of acute and chronic gastric pathologies in humans. Several H. pylori virulence genes that may play a role in its pathogenicity have been identified. The most important determinants are vacA and cagA in the cag pathogenicity island (cagPAI) genes. In the present study, to consider the association of molecular genetics between vacA and the cagPAI regarding clinical outcome, we selected H. pylori strains with various genotypes of vacA in Japan and sequenced full-length vacA, cagA, and cagE genes. Sequencing of vacA and cagA genes revealed variable size, whereas the cagE gene was well conserved among strains. Each of the phylogenetic trees based on the deduced amino acid sequences of VacA, CagA, and CagE indicated that all three proteins were divided into two major groups, a Western group and an East Asian group, and the distributions of isolates exhibited similar patterns among the three proteins. The strains with s2 and s1a/m1a vacA genotypes and the Western-type 3' region cagA genotype were classified into the Western group, and the strains with the s1c/m1b vacA genotype and the East Asian-type 3' cagA genotype were included in the East Asian group. In addition, the prevalence of infection with the Western group strain was significantly higher in patients with peptic ulcer (90.0%, 9/10) than in patients with chronic gastritis (22.7%, 5/22) (chi2 = 12.64, P = 0.00057). These data suggest that the molecular genetics of vacA and cagPAI are associated and that the Western group with vacA and cagPAI genes is associated with peptic ulcer disease. PMID:16081930

  5. The recurrence interval of forest fires in Cabeço da Vaca (Cabreira Mountain--northwest of Portugal).

    PubMed

    Ferreira Leite, Flora; Bento Gonçalves, António; Vieira, António

    2011-02-01

    The recurrence of forest fires is degrading an important part of the Portuguese natural heritage namely its forest and soils. In this paper we present the case study of Cabeço da Vaca (Cabreira Mountain-northwest Portugal), where in recent decades, particularly in the 70s, there was a significant increase in the number of forest fires and in the areas scorched annually. There is thus a turning point between a period when fire was an integral part of the ecosystems and when fire has become a serious threat to woodland management and development (Bento Gonçalves, 2006). Starting with a thorough characterization of forest fires and based on the mapping of scorched areas between 1990 and 2006, we have proceeded to identify the annual pattern of maximum recurrence and the definition of the return interval in Cabeço da Vaca, producing thus a valuable document to support management and forestry development in general. PMID:20576260

  6. A systematic review on the association between the Helicobacter pylori vacA i genotype and gastric disease.

    PubMed

    Liu, Xian; He, Bangshun; Cho, William C; Pan, Yuqin; Chen, Jie; Ying, Houqun; Wang, Feng; Lin, Kang; Peng, Hongxin; Wang, Shukui

    2016-05-01

    Helicobacter pylori (H. pylori) has been recognized as a cause of gastrointestinal diseases and progress of the pathology of gastrointestinal diseases is related to the genotype of H. pylori. Published studies have indicated that the H. pylori vacuolating cytotoxin gene A (vacA) i1/i2 genotype is associated with peptic ulcer disease (PUD) and gastric cancer (GC), but their conclusions are inconsistent. This study aimed to further assess the risk of vacA i gene for PUD and/or GC. A systematic search was conducted across three main electronic databases (PubMed, Web of Science, and CNKI). A meta-analysis was then performed on the pooled data of the published articles to estimate the overall influence of vacA i polymorphisms on PUD and/or GC by crude odds ratio (OR) with 95% confidence intervals (CI). The reliability of the results were confirmed by publication bias and sensitivity analysis of included studies. A total of 14 studies were selected according to the specific inclusion and exclusion criteria. The pooled results revealed that patients with GC were more vulnerable to infection by H. pylori i1 genotype (OR = 5.12; 95% CI: 2.66-9.85; P < 0.001) than those with chronic gastritis or nonulcer disease. Moreover, the results of subgroup analysis indicated that the i1 genotype of H. pylori was associated with an increased GC risk (OR = 10.89; 95% CI: 4.11-20.88; P < 0.001) in the Middle Asian population. The H. pylori vacA i1 genotype is associated with an increased GC risk, especially in the Middle Asian population. PMID:27419046

  7. Role of Helicobacter pylori cagA EPIYA motif and vacA genotypes for the development of gastrointestinal diseases in Southeast Asian countries: a meta-analysis

    PubMed Central

    2012-01-01

    Background Infection with cagA-positive, cagA EPIYA motif ABD type, and vacA s1, m1, and i1 genotype strains of Helicobacter pylori is associated with an exacerbated inflammatory response and increased risk of gastroduodenal diseases. However, it is unclear whether the prevalence and virulence factor genotypes found in Southeast Asia are similar to those in Western countries. Here, we examined the cagA status and prevalence of cagA EPIYA motifs and vacA genotypes among H. pylori strains found in Southeast Asia and examined their association with gastroduodenal disease. Methods To determine the cagA status, cagA EPIYA motifs, and vacA genotypes of H. pylori, we conducted meta-analyses of 13 previous reports for 1,281 H. pylori strains detected from several Southeast Asian countries. Results The respective frequencies of cagA-positive and vacA s1, m1, and i1 genotypes among examined subjects were 93% (1,056/1,133), 98% (1,010/1,033), 58% (581/1,009), and 96% (248/259), respectively. Stratification showed significant variation in the frequencies of cagA status and vacA genotypes among countries and the individual races residing within each respective country. The frequency of the vacA m-region genotype in patients infected with East Asian-type strains differed significantly between the northern and southern areas of Vietnam (p < 0.001). Infection with vacA m1 type or cagA-positive strains was associated with an increased risk of peptic ulcer disease (odds ratio: 1.46, 95%CI: 1.01-2.12, p = 0.046 and 2.83, 1.50-5.34, p = 0.001, respectively) in the examined Southeast Asian populations. Conclusions Both Western- and East Asian-type strains of H. pylori are found in Southeast Asia and are predominantly cagA-positive and vacA s1 type. In Southeast Asia, patients infected with vacA m1 type or cagA-positive strains have an increased risk of peptic ulcer disease. Thus, testing for this genotype and the presence of cagA may have clinical usefulness. PMID

  8. Detection of serum antibodies to CagA and VacA and of serum neutralizing activity for vacuolating cytotoxin in patients with Helicobacter pylori-induced gastritis.

    PubMed Central

    Donati, M; Moreno, S; Storni, E; Tucci, A; Poli, L; Mazzoni, C; Varoli, O; Sambri, V; Farencena, A; Cevenini, R

    1997-01-01

    Thirty patients with dyspepsia, with histological diagnosis of gastritis, and with endoscopic diagnosis of peptic ulcer disease (PUD) (n = 13) or nonulcer dyspepsia (NUD) (n = 17) were admitted to the study. Helicobacter pylori vacuolating cytotoxin-producing strains (Tox+) were isolated from 14 (46.7%) patients, whereas non-cytotoxin-producing (Tox-) H. pylori strains were isolated from the remaining patients. Of 30 patients studied, 20 (66.7%) had serum cytotoxin neutralizing activity in vitro. Fourteen patients with Tox+ H. pylori strains showed serum cytotoxin neutralizing activity and serum immunoglobulin G (IgG) and IgA antibodies reactive with both 87-kDa H. pylori vacuolating cytotoxin (VacA) and 128-kDa cytotoxin-associated gene product (CagA) by immunoblotting using native enriched preparations of VacA and CagA proteins from H. pylori culture supernatants as the antigens. A 94-kDa antigen cross-reacting with the 87-kDa VacA protein could be demonstrated in culture supernatant with immune sera from humans and animals. All patients (n = 10) lacking serum neutralizing activity were also negative for IgG or IgA against VacA antigen, whereas 6 of the 10 patients showed IgG serum antibody responses against CagA antigen. The prevalence of antibodies to VacA and CagA antigens was significantly (P < 0.001) higher in patients with gastritis (20 and 26 patients for VacA and CagA, respectively, of 30 patients) than in H. pylori culture-negative controls (0 of 27 for both VacA and CagA) and in randomly selected blood donors (17 and 21 for VacA and CagA, respectively, of 120 subjects). All patients with PUD had antibodies to CagA, whereas 13 of 17 (76.5%) patients with NUD had anti-CagA antibodies. Serum IgG antibodies to VacA were present in 9 (69.2%) patients with PUD of 13 patients and in 11 (64.7%) patients with NUD of 17 patients. Anti-CagA antibodies seemed to correlate better with PUD than anti-VacA antibodies. PMID:9220168

  9. Evaluation of Clarithromycin Resistance and cagA and vacA Genotyping of Helicobacter pylori Strains from the West of Ireland Using Line Probe Assays

    PubMed Central

    Ryan, Kieran A.; van Doorn, Leen-Jan; Moran, Anthony P.; Glennon, Maura; Smith, Terry; Maher, Majella

    2001-01-01

    The prevalence of clarithromycin resistance-associated mutations, the cytotoxin-associated gene (cagA), and the various vacuolating cytotoxin (vacA) genotypes was determined in 50 gastric biopsy specimens from Helicobacter pylori-infected patients, using line probe assays. The clarithromycin resistance-associated mutation A2143G was detected in H. pylori strains from 26% of the specimens, which suggested that the high rate of H. pylori treatment failure in Ireland may be partly attributable to the presence of these mutations. All strains examined carried the vacA s1 genotype, and 76% were cagA positive. Of these 50 specimens, 13 (26%) carried H. pylori strains with vacA midregion genotype m1, 29 (58%) carried strains that were m2, 1 (2%) was infected by a strain that was positive for both m1 and m2, and 7 (14%) carried strains that could not be typed. PMID:11326028

  10. The Immunomodulator VacA Promotes Immune Tolerance and Persistent Helicobacter pylori Infection through Its Activities on T-Cells and Antigen-Presenting Cells

    PubMed Central

    Djekic, Aleksandra; Müller, Anne

    2016-01-01

    VacA is a pore-forming toxin that has long been known to induce vacuolization in gastric epithelial cells and to be linked to gastric disorders caused by H. pylori infection. Its role as a major colonization and persistence determinant of H. pylori is less well-understood. The purpose of this review is to discuss the various target cell types of VacA and its mechanism of action; specifically, we focus on the evidence showing that VacA targets myeloid cells and T-cells to directly and indirectly prevent H. pylori-specific T-cell responses and immune control of the infection. In particular, the ability of VacA-proficient H. pylori to skew T-cell responses towards regulatory T-cells and the effects of Tregs on H. pylori chronicity are highlighted. The by-stander effects of VacA-driven immunomodulation on extragastric diseases are discussed as well. PMID:27322319

  11. The Immunomodulator VacA Promotes Immune Tolerance and Persistent Helicobacter pylori Infection through Its Activities on T-Cells and Antigen-Presenting Cells.

    PubMed

    Djekic, Aleksandra; Müller, Anne

    2016-01-01

    VacA is a pore-forming toxin that has long been known to induce vacuolization in gastric epithelial cells and to be linked to gastric disorders caused by H. pylori infection. Its role as a major colonization and persistence determinant of H. pylori is less well-understood. The purpose of this review is to discuss the various target cell types of VacA and its mechanism of action; specifically, we focus on the evidence showing that VacA targets myeloid cells and T-cells to directly and indirectly prevent H. pylori-specific T-cell responses and immune control of the infection. In particular, the ability of VacA-proficient H. pylori to skew T-cell responses towards regulatory T-cells and the effects of Tregs on H. pylori chronicity are highlighted. The by-stander effects of VacA-driven immunomodulation on extragastric diseases are discussed as well. PMID:27322319

  12. High Frequency of vacA s1m2 Genotypes Among Helicobacter pylori Isolates From Patients With Gastroduodenal Disorders in Kermanshah, Iran

    PubMed Central

    Pajavand, Hamid; Alvandi, Amirhooshang; Mohajeri, Parviz; Bakhtyari, Somaye; Bashiri, Homayoon; Kalali, Behnam; Gerhard, Markus; Najafi, Farid; Abiri, Ramin

    2015-01-01

    Background: Helicobacter pylori infection and related diseases outcome are mediated by a complex interplay between bacterial, host and environmental factors. Several distinct virulence factors of H. pylori have been shown to be associated with different clinical outcomes. Here we focused on vacA and cagA genotypes of H. pylori strains isolated from patients with gastric disorder. Objectives: The aim of this study was to determine the frequency of two toxins and genotypes of VacA toxin in patients referred to a central hospital in the west of Iran (Imam Reza hospital, Kermanshah) during 2011 - 2012. Patients and Methods: Samples were collected from patients infected with H. pylori. Gastric biopsy specimens from the stomach antrum and corpus were cultured. PCR analysis was performed for genotyping H. pylori vacA and cagA genes. Results: Helicobacter pylori was isolated from 48% (96/200) of patients with gastroduodenal disorders. In 81/96 (84%) cases, the cagA gene was present. Among different genotypes of vacA, two s1m2 and s2m2 genotypes were dominant with frequency of 39.5% and 50%, respectively. The frequency of the s1m1 genotype was 7.2% (7/96), which is much lower than elsewhere. H. pylori isolates with positive results for cagA gene and vacA s1m2 genotypes showed statistically significant correlation with peptic ulcer (s1m2 13/34 [38.2%] P = 0.003). However, isolates of H. pylori infection with cagA gene and vacA s2m2 genotypes were significantly associated with development of gastritis (s2m2 41/42 [97.6%] P = 0.000). Conclusions: About 90% of H. pylori strains potentially contained vacA s2m2 and s1m2 genotypes. Infection with H. pylori strain containing the cagA gene or the vacA s1m1 and s1m2 genotypes was associated with increased incidence of peptic ulcer disease (PUD). PMID:26862378

  13. Relationship between VacA Toxin and Host Cell Autophagy in Helicobacter pylori Infection of the Human Stomach: A Few Answers, Many Questions

    PubMed Central

    Ricci, Vittorio

    2016-01-01

    Helicobacter pylori is a Gram-negative bacterium that colonizes the stomach of about half the global population and represents the greatest risk factor for gastric malignancy. The relevance of H. pylori for gastric cancer development is equivalent to that of tobacco smoking for lung cancer. VacA toxin seems to play a pivotal role in the overall strategy of H. pylori towards achieving persistent gastric colonization. This strategy appears to involve the modulation of host cell autophagy. After an overview of autophagy and its role in infection and carcinogenesis, I critically review current knowledge about the action of VacA on host cell autophagy during H. pylori infection of the human stomach. Although VacA is a key player in modulation of H. pylori-induced autophagy, a few discrepancies in the data are also evident and many questions remain to be answered. We are thus still far from a definitive understanding of the molecular mechanisms through which VacA affects autophagy and the consequences of this toxin action on the overall pathogenic activity of H. pylori. PMID:27376331

  14. Helicobacter pylori VacA Toxin/Subunit p34: Targeting of an Anion Channel to the Inner Mitochondrial Membrane

    PubMed Central

    Harsman, Anke; Papatheodorou, Panagiotis; Reljic, Boris; Dian-Lothrop, Elke A.; Galmiche, Antoine; Kepp, Oliver; Becker, Lars; Günnewig, Kathrin; Wagner, Richard; Rassow, Joachim

    2010-01-01

    The vacuolating toxin VacA, released by Helicobacter pylori, is an important virulence factor in the pathogenesis of gastritis and gastroduodenal ulcers. VacA contains two subunits: The p58 subunit mediates entry into target cells, and the p34 subunit mediates targeting to mitochondria and is essential for toxicity. In this study we found that targeting to mitochondria is dependent on a unique signal sequence of 32 uncharged amino acid residues at the p34 N-terminus. Mitochondrial import of p34 is mediated by the import receptor Tom20 and the import channel of the outer membrane TOM complex, leading to insertion of p34 into the mitochondrial inner membrane. p34 assembles in homo-hexamers of extraordinary high stability. CD spectra of the purified protein indicate a content of >40% β-strands, similar to pore-forming β-barrel proteins. p34 forms an anion channel with a conductivity of about 12 pS in 1.5 M KCl buffer. Oligomerization and channel formation are independent both of the 32 uncharged N-terminal residues and of the p58 subunit of the toxin. The conductivity is efficiently blocked by 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), a reagent known to inhibit VacA-mediated apoptosis. We conclude that p34 essentially acts as a small pore-forming toxin, targeted to the mitochondrial inner membrane by a special hydrophobic N-terminal signal. PMID:20442789

  15. A Tale of Two Toxins: Helicobacter Pylori CagA and VacA Modulate Host Pathways that Impact Disease

    PubMed Central

    Jones, Kathleen R.; Whitmire, Jeannette M.; Merrell, D. Scott

    2010-01-01

    Helicobacter pylori is a pathogenic bacterium that colonizes more than 50% of the world's population, which leads to a tremendous medical burden. H. pylori infection is associated with such varied diseases as gastritis, peptic ulcers, and two forms of gastric cancer: gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma. This association represents a novel paradigm for cancer development; H. pylori is currently the only bacterium to be recognized as a carcinogen. Therefore, a significant amount of research has been conducted to identify the bacterial factors and the deregulated host cell pathways that are responsible for the progression to more severe disease states. Two of the virulence factors that have been implicated in this process are cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA), which are cytotoxins that are injected and secreted by H. pylori, respectively. Both of these virulence factors are polymorphic and affect a multitude of host cellular pathways. These combined facts could easily contribute to differences in disease severity across the population as various CagA and VacA alleles differentially target some pathways. Herein we highlight the diverse types of cellular pathways and processes targeted by these important toxins. PMID:21687723

  16. Expression of cagA, virB/D Complex and/or vacA Genes in Helicobacter pylori Strains Originating from Patients with Gastric Diseases.

    PubMed

    Szkaradkiewicz, Andrzej; Karpiński, Tomasz M; Linke, Krzysztof; Majewski, Przemysław; Rożkiewicz, Dorota; Goślińska-Kuźniarek, Olga

    2016-01-01

    In order to better understand pathogenicity of Helicobacter pylori, particularly in the context of its carcinogenic activity, we analysed expression of virulence genes: cagA, virB/D complex (virB4, virB7, virB8, virB9, virB10, virB11, virD4) and vacA in strains of the pathogen originating from persons with gastric diseases. The studies were conducted on 42 strains of H. pylori isolated from patients with histological diagnosis of non-atrophic gastritis-NAG (group 1, including subgroup 1 containing cagA+ isolates and subgroup 2 containing cagA- strains), multifocal atrophic gastritis-MAG (group 2) and gastric adenocarcinoma-GC (group 3). Expression of H. pylori genes was studied using microarray technology. In group 1, in all strains of H. pylori cagA+ (subgroup 1) high expression of the gene as well as of virB/D was disclosed, accompanied by moderate expression of vacA. In strains of subgroup 2 a moderate expression of vacA was detected. All strains in groups 2 and 3 carried cagA gene but they differed in its expression: a high expression was detected in isolates of group 2 and its hyperexpression in strains of group 3 (hypervirulent strains). In both groups high expression of virB/D and vacA was disclosed. Our results indicate that chronic active gastritis may be induced by both cagA+ strains of H. pylori, manifesting high expression of virB/D complex but moderate activity of vacA, and cagA- strains with moderate expression of vacA gene. On the other hand, in progression of gastric pathology and carcinogenesis linked to H. pylori a significant role was played by hypervirulent strains, manifesting a very high expression of cagA and high activity of virB/D and vacA genes. PMID:26866365

  17. Helicobacter pylori vacA i region polymorphism but not babA2 status associated to gastric cancer risk in northwestern Iran.

    PubMed

    Mottaghi, Batool; Safaralizadeh, Reza; Bonyadi, Morteza; Latifi-Navid, Saeid; Somi, Mohammad Hossein

    2016-02-01

    Helicobacter pylori-specific genotypes have been strongly associated with an increased risk of gastric cancer (GC). The aim of the present work was to study the associations of H. pylori virulence factors, vacA i region polymorphisms and babA2 status with GC risk in Azerbaijan patients. The DNA extracted from gastric biopsy specimens was used to access the babA2 and vacA genotypes. Overall, babA2 was present in 85.39 % (76/89) of H. pylori strains: 19 out of 24 (79.16 %) strains from GC, 16 out of 17 (94.14 %) strains from peptic ulcer disease (PUD) and 41 out of 48 (85.14 %) strains from chronic gastritis. No significant association was found between babA2 genotype and clinical outcomes (P > 0.05). i1 vacA polymorphism was detected in 46/89 (51.68 %) strains: in 21/24 (87.5 %), 6/17 (35.29 %) and 19/48 (39.58 %) patients with GC, PUD and chronic gastritis, respectively. i2 allele was detected in 43 (48.31 %) out of all 89 strains examined: 3 (14.28 %) of 24 strains from GC, 11 (64.71 %) of 17 from PUD, and 29 (60.42 %) of 48 strains from chronic gastritis. In this study, multiple linear regression analysis confirmed the strong association of i1 allele with GC (partial regression correlation 0.455 ± 0.101; P = 0). Results of multiple logistic regression analysis showed that vacA i1 genotype was significantly associated with GC compared with a control group (gastritis) (odds ratio 13.142, 95 % CI 3.116-55.430; P = 0). Findings from the measurement of H. pylori babA2 and vacA genotypes indicate a strong correlation between the vacA i1 allele and GC risk in the Azerbaijan area of Iran. PMID:25472424

  18. Association of IL1B -511C/-31T haplotype and Helicobacter pylori vacA genotypes with gastric ulcer and chronic gastritis

    PubMed Central

    2010-01-01

    Background The association between proinflammatory cytokine gene polymorphisms and gastric diseases related to Helicobacter pylori varies by population and geographic area. Our objective was to determine if the IL-1B -511 T>C and -31 C>T polymorphisms and H. pylori vacA genotypes are associated with risk of chronic gastritis and gastric ulcer in a Mexican population. Methods We conducted endoscopic studies in 128 patients with symptoms of dyspepsia. We took two biopsies from the body, antrum, or ulcer edge from each patient, and classified our histopathological findings according to the Sydney System. H. pylori infection and vacA genotyping were accomplished via PCR from total DNA of the gastric biopsies. We confirmed the presence of anti-H. pylori serum IgG and IgM in 102 control subjects. In both case subjects and control subjects, the IL-1B -511 T>C polymorphism was genotyped by PCR-RFLPs and the IL-1B -31 C>T polymorphism was genotyped by pyrosequencing. Results Sixty-two point seven (62.7%) of the 102 control subjects were H. pylori-seropositive. Among the case subjects, 100 were diagnosed with chronic gastritis and 28 with gastric ulcer. We found that 77% of the patients with chronic gastritis and 85.7% of the patients with gastric ulcer were H. pylori-positive. The predominant H. pylori genotype was vacA s1m1 (58.4%) and the most frequent subtype was vacA s1. The -511 TC, (rs16944 -511 T>C) genotype and the -511C allele were associated with chronic gastritis (OR = 3.1, 95% CI = 1.4-6.8 and OR = 3.0, 95% CI = 1.4-6.0, respectively). The subjects carrying -31T (rs1143627 -31 C>T) were found to be at a higher risk of having chronic gastritis (OR = 2.8, 95% CI = 1.3-5.8). The IL-1B -511C/-31T haplotype was associated with chronic gastritis (OR = 2.1, 95% CI = 1.2-3.8) but not with gastric ulcer. Conclusions The H. pylori vacA genotypes identified herein were similar to those reported for other regions of Mexico. The vacA s1m1 genotype was not associated with

  19. Relationship between Tobacco, cagA and vacA i1 Virulence Factors and Bacterial Load in Patients Infected by Helicobacter pylori

    PubMed Central

    Aguirre, Estefanía; Aragones, Nuria; Saez, Jesús; Galiana, Antonio; Sola-Vera, Javier; Ruiz-García, Montserrat; Paz-Zulueta, María; Sarabia-Lavín, Raquel; Brotons, Alicia; López-Girona, Elena; Pérez, Estefanía; Sillero, Carlos

    2015-01-01

    Background and Aim Several biological and epidemiological studies support a relationship between smoking and Helicobacter pylori (H. pylori) to increase the risk of pathology. However, there have been few studies on the potential synergistic association between specific cagA and vacA virulence factors and smoking in patients infected by Helicobacter pylori. We studied the relationship between smoking and cagA, vacA i1 virulence factors and bacterial load in H. pylori infected patients. Methods Biopsies of the gastric corpus and antrum from 155 consecutive patients in whom there was clinical suspicion of infection by H. pylori were processed. In 106 patients H. pylori infection was detected. Molecular methods were used to quantify the number of microorganisms and presence of cagA and vacA i1 genes. A standardized questionnaire was used to obtain patients’ clinical data and lifestyle variables, including tobacco and alcohol consumption. Adjusted Odds Ratios (ORadjusted) were estimated by unconditional logistic regression. Results cagA was significantly associated with active-smoking at endoscope: ORadjusted 4.52. Evidence of association was found for vacA i1 (ORadjusted 3.15). Bacterial load was higher in active-smokers, although these differences did not yield statistical significance (median of 262.2 versus 79.4 copies of H. pylori per cell). Conclusions The association between smoking and a higher risk of being infected by a virulent bacterial population and with higher bacterial load, support a complex interaction between H. pylori infection and environmental factors. PMID:25794002

  20. Distribution of Helicobacter pylori cagA, cagE, oipA and vacA in different major ethnic groups in Tehran, Iran

    PubMed Central

    Dabiri, Hossein; Maleknejad, Parviz; Yamaoka, Yoshio; Feizabadi, Mohammad M; Jafari, Fereshteh; Rezadehbashi, Maryam; Nakhjavani, Farrokh A; Mirsalehian, Akbar; Zali, Mohammad R

    2011-01-01

    Background and Aim There are geographical variations in Helicobacter pylori virulence genes; cagA, cagE, vacA and oipA. The present study compared the distribution of these genotypes in major ethnic groups residing in Tehran, Iran and their association with clinical outcomes. Methods A total of 124 H. pylori-positive patients living in Tehran were enrolled in this study. The ethnic distribution was 74 Persians, 33 Turks and 17 other ethnics including Kurds, Lurs, Afghanis and Arabs. The presence of the cagA, cagE and oipA genes and vacA alleles (signal [s] and middle [m] region) were determined by polymerase chain reaction (PCR) from H. pylori DNA. Results The cagA-positive status was predominant in all three ethnic groups (e.g. 65% in Persians and 73% in Turks). In contrast, the cagE-positive status was less than half in Persians (47%) and Turks (30%), whereas it was 77% in other ethnicities (P = 0.008). The predominant vacA genotypes were s1 and m1 in all three ethnic groups (e.g. 68% in Persians and 70% in Turks were s1). There was no significant association between cagA and cagE status or vacA genotypes and clinical outcomes. The oipA-positive strains were more common in non-ulcer dyspepsia (NUD) (63%) than in peptic ulcer patients (15%) (P = 0.001) in Persians, but the association was not observed in other ethnic groups. Conclusion There are some differences in the H. pylori genotypes among the ethnic groups in Iran. However, none of these markers seemed to be clinically helpful in predicting the clinical presentation of a H. pylori infection in Iran. PMID:19702906

  1. Fish faunas from the Late Jurassic (Tithonian) Vaca Muerta Formation of Argentina: One of the most important Jurassic marine ichthyofaunas of Gondwana

    NASA Astrophysics Data System (ADS)

    Gouiric-Cavalli, Soledad; Cione, Alberto Luis

    2015-11-01

    The marine deposits of the Vaca Muerta Formation (Tithonian-Berriasian) houses one of the most diverse Late Jurassic ichthyofaunas of Gondwana. However, most of the specimens remain undescribed. Jurassic fishes have been recovered from several localities at Neuquén Province (i.e., Picún Leufú, Plaza Huincul, Cerro Lotena, Portada Las Lajas, Los Catutos, and Arroyo Covunco) but also from Mendoza Province (i.e., La Valenciana, Los Molles, and Arroyo del Cajón Grande). Presently, the fish fauna of Los Catutos, near Zapala city (Neuquén Province), has yielded the highest number of specimens, which are taxonomically and morphologically diverse. At Los Catutos locality, the Vaca Muerta Formation is represented by the Los Catutos Member, which is considered the only lithographic limestones known in the Southern Hemisphere. Here, we review the Tithonian fish faunas from the Vaca Muerta Formation. During Late Jurassic times, the actual Argentinian territory could have been a morphological diversification center, at least for some actinopterygian groups. The apparently lower species diversity recorded in marine Jurassic ichthyofaunas of Argentina (and some Gondwanan countries) in comparison with Chilean and European fish faunas could be related to the fish paleontological research history in Gondwana and the low number of detailed studies of most of specimens recorded.

  2. Prevalence of cagA and vacA among Helicobacter pylori-infected patients in Iran: a systematic review and meta-analysis.

    PubMed

    Sayehmiri, Fatemeh; Kiani, Faezeh; Sayehmiri, Kourosh; Soroush, Setareh; Asadollahi, Khairollah; Alikhani, Mohammad Yousef; Delpisheh, Ali; Emaneini, Mohammad; Bogdanović, Lidija; Varzi, Ali Mohammad; Zarrilli, Raffaele; Taherikalani, Morovat

    2015-07-01

    The varieties of infections caused by Helicobacter pylori may be due to differences in bacterial genotypes and virulence factors as well as environmental and host-related factors. This study aimed to investigate the prevalence of cagA and vacA genes among H. pylori-infected patients in Iran and analyze their relevance to the disease status between two clinical groups via a meta-analysis method. Different databases including PubMed, ISI, Scopus, SID, Magiran, Science Direct, and Medlib were investigated, and 23 relevant articles from the period between 2001 and 2012 were finally analyzed. The relevant data obtained from these papers were analyzed by a random-effects model. Data were analyzed using R software and STATA. The prevalence of cagA and vacA genes among H. pylori-infected patients was 70% (95% CI, 64-75) and 41% (95% CI, 24.3-57.7), respectively. The prevalence of duodenal ulcers, peptic ulcers, and gastritis among cagA+ individuals was 53% (95% CI, 20-86), 65% (95% CI, 34-97), and 71% (95% CI, 59-84), respectively. Odds ratio (OR) between cagA-positive compared with cagA-negative patients showed a 1.89 (95% CI, 1.38-2.57) risk of ulcers. In conclusion, the frequency of cagA gene among H. pylori strains is elevated in Iran and it seems to be more frequently associated with gastritis. Therefore, any information about cagA and vacA prevalence among different H. pylori-infected clinical groups in the country can help public health authorities to plan preventive policies to reduce the prevalence of diseases associated with H. pylori infection. PMID:26230117

  3. Helicobacter pylori Genotyping from American Indigenous Groups Shows Novel Amerindian vacA and cagA Alleles and Asian, African and European Admixture

    PubMed Central

    Camorlinga-Ponce, Margarita; Perez-Perez, Guillermo; Gonzalez-Valencia, Gerardo; Mendoza, Irma; Peñaloza-Espinosa, Rosenda; Ramos, Irma; Kersulyte, Dangeruta; Reyes-Leon, Adriana; Romo, Carolina; Granados, Julio; Muñoz, Leopoldo; Berg, Douglas E.; Torres, Javier

    2011-01-01

    It is valuable to extend genotyping studies of Helicobacter pylori to strains from indigenous communities across the world to better define adaption, evolution, and associated diseases. We aimed to genetically characterize both human individuals and their infecting H. pylori from indigenous communities of Mexico, and to compare them with those from other human groups. We studied individuals from three indigenous groups, Tarahumaras from the North, Huichols from the West and Nahuas from the center of Mexico. Volunteers were sampled at their community site, DNA was isolated from white blood cells and mtDNA, Y-chromosome, and STR alleles were studied. H. pylori was cultured from gastric juice, and DNA extracted for genotyping of virulence and housekeeping genes. We found Amerindian mtDNA haplogroups (A, B, C, and D), Y-chromosome DYS19T, and Amerindian STRs alleles frequent in the three groups, confirming Amerindian ancestry in these Mexican groups. Concerning H.pylori cagA phylogenetic analyses, although most isolates were of the Western type, a new Amerindian cluster neither Western nor Asian, was formed by some indigenous Mexican, Colombian, Peruvian and Venezuelan isolates. Similarly, vacA phylogenetic analyses showed the existence of a novel Amerindian type in isolates from Alaska, Mexico and Colombia. With hspA strains from Mexico and other American groups clustered within the three major groups, Asian, African or European. Genotyping of housekeeping genes confirmed that Mexican strains formed a novel Asian-related Amerindian group together with strains from remote Amazon Aborigines. This study shows that Mexican indigenous people with Amerindian markers are colonized with H. pylori showing admixture of Asian, European and African strains in genes known to interact with the gastric mucosa. We present evidence of novel Amerindian cagA and vacA alleles in indigenous groups of North and South America. PMID:22073291

  4. Multilayer adsorption of Cu(II) and Cd(II) over Brazilian Orchid Tree (Pata-de-vaca) and its adsorptive properties

    NASA Astrophysics Data System (ADS)

    Jorgetto, Alexandre de O.; da Silva, Adrielli C. P.; Wondracek, Marcos H. P.; Silva, Rafael I. V.; Velini, Edivaldo D.; Saeki, Margarida J.; Pedrosa, Valber A.; Castro, Gustavo R.

    2015-08-01

    Through very simple and inexpensive processes, pata-de-vaca leaves were turned into a powder and applied as an adsorbent for the uptake of Cu(II) and Cd(II) from water. The material was characterized through SEM, EDX, FTIR and surface area measurement. The material had its point of zero charge determined (5.24), and its adsorption capacity was evaluated as a function of time, pH and metal concentration. The material presented fast adsorption kinetics, reaching adsorption equilibrium in less than 5 min and it had a good correlation with the pseudo-second order kinetic model. Optimum pH for the adsorption of Cu(II) and Cd(II) were found to be in the range from 4 to 5, approximately. In the experiment as a function of the analyte concentration, analogously to gas adsorption, the material presented a type II isotherm, indicating the formation of multilayers for both species. Such behavior was explained with basis in the alternation between cations and anions over the material's surface, and the maximum adsorption capacity, considering the formation of the multilayers were found to be 0.238 mmol L-1 for Cu(II) and 0.113 mmol L-1 for Cd(II).

  5. Helicobacter pylori isolated from Iranian drinking water: vacA, cagA, iceA, oipA and babA2 genotype status and antimicrobial resistance properties.

    PubMed

    Ranjbar, Reza; Khamesipour, Faham; Jonaidi-Jafari, Nematollah; Rahimi, Ebrahim

    2016-05-01

    Despite the clinical importance of Helicobacter pylori in human gastric disorders, its exact route of transmission is still uncertain. Based on the contentious hypothesis and findings of previous investigations, water may play an important role in the transmission of H. pylori to humans. This study was carried out to investigate the vacA, cagA, oipA, iceA and babA2 genotype status and antimicrobial resistance properties of H. pylori strains isolated from the drinking water samples of four major provinces in Iran. A total of 400 drinking water samples were cultured and tested. H. pylori-positive strains were analyzed for the presence of various genotypes and antimicrobial resistance. Twelve of 400 (3%) water samples were positive for H. pylori. Samples from Isfahan province had the highest, while those from Shiraz had the lowest prevalence of H. pylori. The seasonal distribution was also determined, with the highest prevalence of bacteria in the summer season (7.36%). H. pylori strains harbored the highest levels of resistance against ampicillin (100%), erythromycin (75%), clarithromycin (75%), and trimethoprim (58.3%). The most commonly detected genotypes were vacAs1a (83.3%), vacAm1a (66.6%), vacAs2 (50%) and cagA (50%). The presence of similar genotypes in the H. pylori strains of drinking water and those of human clinical samples suggest that contaminated water maybe the sources of bacteria. Spiramycin and furazolidone are suggested for the treatment of cases of H. pylori infection. PMID:27419049

  6. Characterizing an unconventional reservoir with conventional seismic data: A case study using seismic inversion for the Vaca Muerta Formation, Neuquen Basin, Argentina

    NASA Astrophysics Data System (ADS)

    Fernandez-Concheso, Jorge E.

    Reservoir characterization for unconventional shale plays ideally requires multi-component, wide-azimuth, long-offset surface seismic data. These data are generally not available, especially in exploration or pre-development stages. Furthermore, it is common to have only a few wells over a large area, along with non-existent or scarce microseismic, engineering and production data. This thesis presents a methodology and workflow to deal with these circumstances of limited data availability. By using a narrow-azimuth, regional P-wave seismic volume and integrating it with wireline logs, cuttings and PLT data, the variability in the geomechanical properties of the Vaca Muerta Formation in Argentina's Neuquen Basin, and their relationships with lithology, stress state and total organic content, were analyzed. Post-stack and pre-stack inversions were performed on the seismic volume. The un- certainties inherent from limited well control in the estimation of elastic properties were investigated using blind well testing. Sensitivity and error analysis was conducted on post-stack vs pre-stack derived P-impedance, the choice of the inversion algorithm (model-based vs sparse-spike) and the definition of the low frequency model (simple kriging model vs complex model derived from multi-attribute stepwise regression) were examined. Also, the use of isotropic AVA equations to approximate the anisotropic (VTI) behaviour of the reservoir was evaluated, using estimates of Thomsen parameters and simple AVA modelling. The integration of the inversion results with the petrophysical analysis and the mechanical stratigraphy work by Bishop (2015), suggests that the rock composition has the largest influence on the geomechanical behaviour of the reservoir. Overpressure is also a major driving factor in that it controls changes in elastic properties. Bishop's cluster analysis was used to identify good quality rock classes. The probabilistic interpretation of these rock classes from seismic

  7. Nuevas Perspectivas en la Efficiencia del Uso Nirogeno en Vaca Lecheras

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dairy cows utilize feed crude protein (CP) with greater efficiency than other ruminants, but still excrete about 2 to 3 times more nitrogen (N) in manure than they secrete in milk. This increases milk production costs plus environmental N pollution. Optimizing microbial protein formation in the rume...

  8. MEJORANDO LA UTILIZACION DE LA PROTEINA EN LA VACA LECHERA EN LACTANCIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dairy cows utilize feed CP with greater efficiency than other ruminants, but still excrete about 2 to 3 times more N in manure than they secrete in milk. This increases milk production costs plus environmental N pollution. Maximizing microbial protein formation in the rumen is the most effective way...

  9. ESTRATEGIAS PARA HACER EL MEJOR USO DE LA PROTEINA EN RACIONES PARA VACAS LECHERAS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dairy cows utilize feed CP with greater efficiency than other ruminants, but still excrete about 2 to 3 times more N in manure than they secrete in milk. This increases milk production costs plus environmental N pollution. Optimizing microbial protein formation in the rumen is the most effective way...

  10. Field evaluation of three plant-based insect repellents against malaria vectors in Vaca Diez Province, the Bolivian Amazon.

    PubMed

    Moore, Sarah J; Lenglet, Annick; Hill, Nigel

    2002-06-01

    The efficacy of repellents against Anopheles darlingi, the main malaria vector in Bolivia, was evaluated. This mosquito has a peak in biting activity early in the evening. Three natural repellents (1 eucalyptus based, 1 neem based, and 1 containing several repellent essential oils) were tested in comparison with 15% deet in human landing catches in Bolivia. The eucalyptus-based repellent containing 30% p-menthane-diol applied at a dose similar to those used in practice gave 96.89% protection for 4 h. Deet gave 84.81% protection. The other 2 products did not provide significant protection from mosquito bites. PMID:12083351

  11. Newly Discovered Paleocene and Eocene Rocks near Fairfield, California, and Correlation with Rocks in Vaca Valley and the So-Called Martinez Formation or Stage

    USGS Publications Warehouse

    Brabb, Earl E.; Ristau, Donn; Bukry, David; McDougall, Kristin; Almgren, Alvin A.; Saul, LouElla; Sanfilippo, Annika

    2008-01-01

    Discovery of a 3-foot thick sandstone bed with abundant Turritellid gastropods of late Paleocene age about 4 miles northeast of Fairfield and on the southwest flank of Cement Hill, Solano County provides an opportunity to reevaluate the relationships of lower Tertiary formations in this part of California. Cement Hill is named for travertine deposits in and on top of sandstone of Late Cretaceous age. In this report, the current study area where the Paleocene fossils were recently discovered is referred to as lower Cement Hill and is located in section 7 of the U.S. Geological Survey Fairfield North 7.5-minute quadrangle, Township 5 North, Range 1 West. Lower Cement Hill is about 23 miles north of the so-called Martinez 'formation' or stage area (Weaver and others, 1941) of late Paleocene age near Martinez. The Martinez 'formation' and stage have played a significant role in the development of early Tertiary stratigraphy in this part of California. The discovery of correlative rocks at Cement Hill was unsuspected and may be helpful in defining the extent of this so-called formation or stage. Coccolith identification and correlations are by David Bukry, foraminifer identifications and correlations by Alvin Almgren and Kristin McDougall, gastropod identification and correlation by LouElla Saul, and Radiolaria identifications and correlations are by Annika Sanfilippo.

  12. VacA’s Induction of VacA-Containing Vacuoles (VCVs) and Their Immunomodulatory Activities on Human T Cells

    PubMed Central

    Utsch, Ciara; Haas, Rainer

    2016-01-01

    Vacuolating cytotoxin A (VacA) is a secreted pore-forming toxin and one of the major virulence factors of Helicobacter pylori (H. pylori), which actively supports the persistence and survival of the bacteria in the special ecological niche of the human stomach. H. pylori genomes harbor different allelic forms of the vacA gene, which translate into functionally distinct VacA toxin types. VacA internalizes into various cell types via membrane or specific receptor interactions finally forming acidic endocytic VacA-containing vacuoles (VCVs). In this review, we focus on different characteristics of VacA, its interaction with host cells, the formation and protein content of VCVs and their intracellular transport into human T cells, which finally leads to the immunosuppressive phenotype of VacA. Immunomodulatory activities of VacA on human T cells are discussed with a focus on T-cell proliferation and calcium signaling. PMID:27322323

  13. Detección de compuestos inductores de aborto en acículas de enebro (Juniperus communis) y suero de vacas abortadas en los montes de la Rioja

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over recent years, there have been observed in several cattle farms within the region of the Sierra de Cameros (La Rioja) mountains, reproductive alterations consisting of pre-mature births and birth of dead calves or calves of reduced viability. After laboratory examination of several cases with ne...

  14. Observations on the Use of Manual Signs and Gestures in the Communicative Interactions between Native Americans and Spanish Explorers of North America: The Accounts of Bernal Diaz del Castillo and Alvar Nunez Cabeza de Vaca

    ERIC Educational Resources Information Center

    Bonvillian, John D.; Ingram, Vicky L.; McCleary, Brendan M.

    2009-01-01

    The accounts of two men who participated in several Spanish-led expeditions to the New World in the early 1500s document the frequent use of manual signs and gestures in the initial interactions between European explorers and the indigenous peoples of North America. Bernal Diaz del Castillo described the events that occurred during three…

  15. 76 FR 64937 - Combined Notice of Filings #1

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-19

    ... Company. Description: Notices of Termination of CalPeak Vaca Dixon and Panoche Service Agreement Nos. 39...: http://www.ferc.gov/docs-filing/efiling/filing-req.pdf . For other information, call (866)...

  16. Reciprocal impact of host factors and Helicobacter pylori genotypes on gastric diseases

    PubMed Central

    Honarmand-Jahromy, Sahar; Siavoshi, Farideh; Malekzadeh, Reza; Nejad Sattari, Taher; Latifi-Navid, Saeid

    2015-01-01

    AIM: To assess the impact of Helicobacter pylori (H. pylori) genotypes and patient age and sex on the development of gastric diseases. METHODS: H. pylori-infected patients (n = 233) referred to the endoscopy unit at Tehran University of Medical Sciences (Tehran, Iran) were diagnosed with chronic gastritis (CG), gastric ulcer (GU), or duodenal ulcer (DU). Brucella blood agar was used for biopsy cultures and H. pylori isolation under microaerobic conditions. H. pylori isolates were confirmed with biochemical tests and through amplification of the 16S rRNA gene. DNA was extracted from fresh cultures of the H. pylori isolates and used for amplification of vacA alleles and the cagA gene. Statistical analysis was performed to determine the association between H. pylori genotypes, age (< 40 years vs > 40 years) and sex of the patient, and gastric diseases. RESULTS: CG was the most prevalent gastric disease (113/233; 48.5%), compared to GU (64/233; 27.5%) and DU (56/233; 24%). More patients were male, and gastric diseases were more frequent in patients > 40 years (P < 0.05). The percentage of CG and GU patients that were male and female did not show a significant difference; however DU was more common in males (P < 0.05). Interestingly, a diagnosis of CG in patients > 40 years was more common in females (18.5%) than males (11.6%) (P = 0.05), whereas a diagnosis of GU or DU in patients > 40 years was more frequent in males (14.6% vs 10.7% and 12.4% vs 4.3%, respectively). Overall, genotyping of the H. pylori isolates revealed that the vacA s1 (82%), vacA m2 (70%), and cagA+ (72.5%) alleles were more frequent than vacA s2 (18%), vacA m1 (29.2%), and cagA- (all P < 0.05). The vacA s1m2cagA+ genotype was the most prevalent within the three disease groups. vacA s1m2 frequency was 56.2% with a similar occurrence in all diagnoses, while vacA s1m1 appeared more often in DU patients (33.9%). A genotype of vacA s2m2 occurred in 15% of isolates and was more common in CG patients (21

  17. Evolution of the Helicobacter pylori Vacuolating Cytotoxin in a Human Stomach

    PubMed Central

    Aviles-Jimenez, Francisco; Letley, Darren P.; Gonzalez-Valencia, Gerardo; Salama, Nina; Torres, Javier; Atherton, John C.

    2004-01-01

    We describe two subclones of Helicobacter pylori, isolated contemporaneously from a human stomach, which differ markedly in the vacuolating cytotoxin gene, vacA, but whose near identity in sequences outside this locus implies a very recent common origin. The differences are consistent with homologous recombination with DNA from another strain and result in a changed vacA midregion and, importantly, in changed toxicity. PMID:15262958

  18. Prevalence of the Helicobacter pylori babA2 gene and correlation with the degree of gastritis in infected Slovenian children.

    PubMed

    Homan, Matjaž; Šterbenc, Anja; Kocjan, Boštjan J; Luzar, Boštjan; Zidar, Nina; Orel, Rok; Poljak, Mario

    2014-10-01

    The aims of our study were to determine the prevalence of the babA2 gene within Helicobacter pylori strains circulating in the Slovenian pediatric population, to further clarify its significance in causing inflammation of gastric mucosa in children and to verify whether cagA, vacA, iceA and babA genes work independently or synergistically in causing gastritis. A total of 163 H. pylori isolates obtained from the same number of children were tested for the presence of cagA, vacA and iceA genes using previously established methods, while the babA2 gene was determined using novel polymerase chain reaction assay targeting a 139-bp fragment of the central region of babA2. The babA2 gene was detected in 47.9% of H. pylori samples. The presence of the babA2 gene was strongly associated with cagA, vacA s1 and vacA m1 genotype. The babA2 status correlated positively with bacterial density score, activity of inflammation and chronic inflammation of gastric mucosa. No significant correlation was found between the babA2 status and the presence of atrophy or intestinal metaplasia. In addition, the activity of gastric inflammation and density score were significantly associated with the coexpression of the cagA, vacA s1, vacA m1 and babA2 genes. The study, which included the largest number of pediatric H. pylori samples to date, confirmed that babA2 gene plays an important role in the pathogenesis of H. pylori gastritis in children. Furthermore, our results suggest that babA2, cagA and vacA s1 and m1 gene products may work synergistically in worsening the inflammation of gastric mucosa. PMID:25055876

  19. The Prevalence of Helicobacter pylori Virulence Factors in Bhutan, Vietnam, and Myanmar Is Related to Gastric Cancer Incidence

    PubMed Central

    Trang, Tran Thi Huyen; Shiota, Seiji; Matsuda, Miyuki; Binh, Tran Thanh; Suzuki, Rumiko; Vilaichone, Ratha-korn; Mahachai, Varocha; Tshering, Lotay; Dung, Ho D. Q.; Uchida, Tomohisa; Matsunari, Osamu; Myint, Thein; Khien, Vu Van; Yamaoka, Yoshio

    2015-01-01

    Gastric cancer is a significant health problem in Asia. Although the prevalence of Helicobacter pylori infection is similar in Bhutan, Vietnam, and Myanmar, the incidence of gastric cancer is highest in Bhutan, followed by Vietnam and Myanmar. We hypothesized that H. pylori virulence factors contribute to the differences. The status of cagA, vacA, jhp0562, and β-(1,3)galT(jhp0563) was examined in 371 H. pylori-infected patients from Bhutan, Vietnam, and Myanmar. Each virulence factor could not explain the difference of the incidence of gastric cancer. However, the prevalence of quadruple-positive for cagA, vacA s1, vacA m1, and jhp0562-positive/β-(1,3)galT-negative was significantly higher in Bhutan than in Vietnam and Myanmar and correlated with gastric cancer incidence. Moreover, gastritis-staging scores measured by histology of gastric mucosa were significantly higher in quadruple-positive strains. We suggest that the cagA, vacA s1, vacA m1, and jhp0562-positive/β-(1,3)galT-negative genotype may play a role in the development of gastric cancer. PMID:26090448

  20. The Characterization of Helicobacter pylori DNA Associated with Ancient Human Remains Recovered from a Canadian Glacier

    PubMed Central

    Swanston, Treena; Haakensen, Monique; Deneer, Harry; Walker, Ernest G.

    2011-01-01

    Helicobacter pylori is a gram-negative bacterium that colonizes the stomach of nearly half of the world's population. Genotypic characterization of H. pylori strains involves the analysis of virulence-associated genes, such as vacA, which has multiple alleles. Previous phylogenetic analyses have revealed a connection between modern H. pylori strains and the movement of ancient human populations. In this study, H. pylori DNA was amplified from the stomach tissue of the Kwäday Dän Ts'ìnchi individual. This ancient individual was recovered from the Samuel Glacier in Tatshenshini-Alsek Park, British Columbia, Canada on the traditional territory of the Champagne and Aishihik First Nations and radiocarbon dated to a timeframe of approximately AD 1670 to 1850. This is the first ancient H. pylori strain to be characterized with vacA sequence data. The Tatshenshini H. pylori strain has a potential hybrid vacA m2a/m1d middle (m) region allele and a vacA s2 signal (s) region allele. A vacA s2 allele is more commonly identified with Western strains, and this suggests that European strains were present in northwestern Canada during the ancient individual's time. Phylogenetic analysis indicated that the vacA m1d region of the ancient strain clusters with previously published novel Native American strains that are closely related to Asian strains. This indicates a past connection between the Kwäday Dän Ts'ìnchi individual and the ancestors who arrived in the New World thousands of years ago. PMID:21359221

  1. Helicobacter pylori induced interleukin-8 expression in gastric epithelial cells is associated with CagA positive phenotype.

    PubMed Central

    Crabtree, J E; Covacci, A; Farmery, S M; Xiang, Z; Tompkins, D S; Perry, S; Lindley, I J; Rappuoli, R

    1995-01-01

    AIMS--To use a range of natural phenotypically variant strains of Helicobacter pylori with disparate CagA and VacA (vacuolating cytotoxin) expression to determine which bacterial factors are more closely associated with epithelial interleukin-8 (IL-8) induction. METHODS--Gastric epithelial cells (AGS and KATO-3) were co-cultured with five H pylori strains which were variously shown to express the cagA gene/CagA protein, VacA and/or to exhibit biological cytotoxicity. Secreted IL-8 was assayed by enzyme leaked immunosorbent assay (ELISA) and IL-8 messenger RNA (mRNA) was assayed using a reverse transcription polymerase chain reaction based technique (RT-PCR). RESULTS--Strains expressing CagA, including a variant strain (D931) which is non-cytotoxic and does not express the VacA protein, were found to upregulate epithelial IL-8 secretion and gene expression. In contrast, strains with no CagA expression, even in the presence of VacA and/or biological cytotoxicity, (G104, BA142), failed to induce IL-8 protein or mRNA above control values. CONCLUSIONS--These results strongly support a role for H pylori CagA or coexpressed factors other than the cytotoxin in upregulation of gastric epithelial IL-8. Increased epithelial IL-8 secretion and concomitant neutrophil chemotaxis and activation in addition to direct cytotoxicity may be an important factor in tissue damage and ulceration. Images PMID:7706517

  2. 78 FR 67133 - Combined Notice of Filings #1

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-08

    ... Commission received the following land acquisition reports: Docket Numbers: LA13-3-000. Applicants: CalPeak Power LLC, CalPeak Power--Border LLC, CalPeak Power--Enterprise LLC, CalPeak Power--Panoche LLC, CalPeak Power--Vaca Dixon LLC Starwood Power-Midway LLC. Description: Quarterly Land Acquisition Report of...

  3. Conservation of Helicobacter pylori genotypes in different ethnic groups in Houston, Texas.

    PubMed

    Yamaoka, Y; Malaty, H M; Osato, M S; Graham, D Y

    2000-06-01

    This study was concerned with whether the Helicobacter pylori strains circulating among ethnic groups living in the same region differ. The polymerase chain reactions to genotype (cagA, vacA, and iceA) H. pylori isolates from healthy volunteers from 4 ethnic groups (black, n=35; white Hispanic, n=31; whites, n=30; Vietnamese, n=29) residing in Houston were examined. The Vietnamese volunteers had the "East Asian"-type cagA 3' repeat region structure, and the others had the "non-Asian" type. The most common genotypes were delineated as follows: blacks and Hispanics, cagA+, vacA s1b-m1, and iceA2; whites, cagA+, vacA s1a-m2, and iceA2; and Vietnamese, cagA+, vacA s1c-m2, and iceA2. Two Hispanic families were also examined. H. pylori isolates from the children and their mothers had the same genotype and were different from those associated with the children's fathers or brothers-in-law. Conservation of an H. pylori genotype within ethnic groups over the course of generations will prove useful for epidemiological study of the coevolution of humans and H. pylori. PMID:10837199

  4. H pylori iceA alleles are disease-specific virulence factors

    PubMed Central

    Caner, Vildan; Yilmaz, Mustafa; Yonetci, Nadir; Zencir, Sevil; Karagenc, Nedim; Kaleli, Ilknur; Bagci, Huseyin

    2007-01-01

    AIM: To characterize and compare genotype profiles of H pylori strains isolated from patients with chronic gastritis and duodenal ulcer in western part of Turkey. METHODS: A total of 46 patients [30 chronic gastritis (CG) and 16 duodenal ulcer (DU)] who had undergone endoscopy because of dyspeptic complaints were studied. The antral biopsy specimens were evaluated for the presence of H pylori by rapid urease test and culture, and the genotype profiles were determined by real-time PCR. RESULTS: The cagA gene was observed in 43 (93.5%) isolates. The vacA s1m2 genotype was the predominant subtype, found in 63.3% and 68.7% of isolates in patients with CG and DU, respectively. Twenty (66.6%) isolates from patients with CG were iceA2 positive while the iceA1 was predominant in those with DU (68.8%). In terms of the association of the iceA alleles to other genes, both alleles were significantly associated with the cagA vacA s1m2 genotype. CONCLUSION: The prevalent circulating genotypes in CG and DU were cagA vacA s1m2 iceA2 and cagA vacA s1m2 iceA1 genotype, respectively. It was found that cagA vacA s1m2 genotype seems to be common virulence factors in both CG and DU while iceA alleles show specificity for gastroduodenal pathologies in this study. PMID:17552005

  5. Virulence genotypes and drug resistance of Helicobacter pylori from Vladivostok, Russia: another feature in the Far East.

    PubMed

    Reva, Ivan; Takano, Tomomi; Higuchi, Wataru; Iwao, Yasuhisa; Taneike, Ikue; Nakagawa, Saori; Ike, Masami; Pererva, Oleg; Tarankov, Alexey; Agapov, Mikhail; Rizhkov, Evgeniy; Singur, Olga; Reva, Galina; Potapov, Vladimir; Yamamoto, Tatsuo

    2012-03-01

    Helicobacter pylori in Vladivostok, Far Eastern Russia, was investigated during 2004 to 2009. The genotype cagA(+) vacA(+) (s1/m1 or m2) accounted for 74.7%, with cagA(-) vacA(+) (s2/m2) at 11.2%. The CagA EPIYA type was mainly Western ABC, with minor types (ABCCC and novel AAABC) or non-Western/non-East Asia type (AB). Regarding drug resistance, metronidazole resistance was the highest, with a marked decrease in 6 years (from 71.4% to 30.8%); in contrast, levofloxacin and clarithromycin resistance increased. The data indicate that in Vladivostok, H. pylori was mainly the Western (not East Asian) type and dynamic changes in drug resistance occurred during 6 years. PMID:22211953

  6. Geographic differences in gastric cancer incidence can be explained by differences between Helicobacter pylori strains.

    PubMed

    Yamaoka, Yoshio; Kato, Mototsugu; Asaka, Masahiro

    2008-01-01

    Certain populations with high incidences of Helicobacter pylori infection, such as those in East Asian countries, have high incidences of gastric cancer, while other highly infected populations, such as those in Africa and South Asia, do not. The various rates of gastric cancer associated with different geographic areas can be explained, at least in part, by the differences in the genotypes of H. pylori cagA and vacA. Populations expressing a high incidence of gastric cancer are mostly identical with regions where East Asian type CagA is predominant. In contrast, incidence of gastric cancer is low in Africa, South Asia, and Europe, where strains typically possess Western type CagA. Within East Asia, strains from northern parts, where the incidence of gastric cancer is high, predominantly possess the vacA m1 genotype, whereas the m2 genotype is predominant in southern parts where the gastric cancer incidence is low. PMID:18552463

  7. Geographic Differences in Gastric Cancer Incidence Can be Explained by Differences between Helicobacter pylori Strains

    PubMed Central

    Yamaoka, Yoshio; Kato, Mototsugu; Asaka, Masahiro

    2013-01-01

    Certain populations with high incidences of Helicobacter pylori infection, such as those in East Asian countries, have high incidences of gastric cancer, while other highly infected populations, such as those in Africa and South Asia, do not. The various rates of gastric cancer associated with different geographic areas can be explained, at least in part, by the differences in the genotypes of H. pylori cagA and vacA. Populations expressing a high incidence of gastric cancer are mostly identical with regions where East Asian type CagA is predominant. In contrast, incidence of gastric cancer is low in Africa, South Asia, and Europe, where strains typically possess Western type CagA. Within East Asia, strains from northern parts, where the incidence of gastric cancer is high, predominantly possess the vacA m1 genotype, whereas the m2 genotype is predominant in southern parts where the gastric cancer incidence is low. PMID:18552463

  8. Helicobacter pylori in North and South America before Columbus.

    PubMed

    Yamaoka, Yoshio; Orito, Etsuro; Mizokami, Masashi; Gutierrez, Oscar; Saitou, Naruya; Kodama, Tadashi; Osato, Michael S; Kim, Jong G; Ramirez, Francisco C; Mahachai, Varocha; Graham, David Y

    2002-04-24

    We present a molecular epidemiologic study, based on an analysis of vacA, cagA and cag right end junction genotypes from 1042 Helicobacter pylori isolates, suggesting that H. pylori was present in the New World before Columbus. Eight Native Colombian and Alaskan strains possessed novel vacA and/or cagA gene structures and were more closely related to East Asian than to non-Asian H. pylori. Some Native Alaskan strains appear to have originated in Central Asia and to have arrived after strains found in South America suggesting that H. pylori crossed the Bering Strait from Asia to the New World at different times. PMID:12062433

  9. 78 FR 41792 - Combined Notice of Filings #1

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-11

    ...-003; ER10-3071-003; ER10-3257-002. Applicants: CalPeak Power LLC, CalPeak Power--Border LLC, CalPeak Power--Enterprise LLC, CalPeak Power--Vaca Dixon LLC, CalPeak Power-- Panoche LLC, Starwood Power-Midway, LLC. Description: Updated Market Power Analysis for the Southwest Region of the CalPeak Entities,...

  10. 78 FR 32381 - Combined Notice of Filings #1

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-30

    ...; ER10-3071-001; ER11-4266- 005; ER10-3257-001. Applicants: CalPeak Power--Border LLC, CalPeak Power--Enterprise LLC, CalPeak Power--Panoche LLC, CalPeak Power--Vaca Dixon LLC, CalPeak Power LLC, Chambers.../efiling/filing-req.pdf . For other information, call (866) 208-3676 (toll free). For TTY, call (202)...

  11. Complete Genome Sequence of Helicobacter pylori Strain 7C Isolated from a Mexican Patient with Chronic Gastritis

    PubMed Central

    Mucito-Varela, Eduardo; Castillo-Rojas, Gonzalo; Cevallos, Miguel A.; Lozano, Luis; Merino, Enrique; López-Leal, Gamaliel

    2016-01-01

    Helicobacter pylori-induced gastritis is a risk factor for developing gastric pathologies. Here, we report the complete genome sequence of a multidrug-resistant H. pylori strain isolated from a chronic gastritis patient in Mexico City, Mexico. Nonvirulent VacA and cag-pathogenicity island (PAI) genotypes were found, but the presence of a potential mobilizable plasmid carrying an IS605 element is of outstanding interest. PMID:26744372

  12. Modulation of the CD4+ T-cell response by Helicobacter pylori depends on known virulence factors and bacterial cholesterol and cholesterol α-glucoside content.

    PubMed

    Beigier-Bompadre, Macarena; Moos, Verena; Belogolova, Elena; Allers, Kristina; Schneider, Thomas; Churin, Yuri; Ignatius, Ralf; Meyer, Thomas F; Aebischer, Toni

    2011-11-01

    Helicobacter pylori blocks the proliferation of human CD4(+) T cells, facilitated by vacuolating exotoxin (VacA) and γ-glutamyl transpeptidase (GGT). H. pylori-triggered T-cell reactions in mice correlate with bacterial cholesterol and cholesterol α-glucoside content but their role in human cells is unclear. We characterized the effect of VacA, GGT, and cholesterol on T-helper 1, T-helper 2, T-regulatory and T-helper 17 associated cytokines and T-cell proliferation. VacA, GGT, and bacterial cholesterol content exhibited differential and synergistic inhibitory effects on the expression of activation markers CD25 and CD69 and on interleukin 2, interleukin 4, interleukin 10, and interferon γ production. These factors did not affect the H. pylori-mediated abrogation of transforming growth factor β secretion or increased interleukin 6 production. Cholesterol α-glucosyltransferase-deficient bacteria exerted strongly reduced antiproliferative effects on primary human CD4(+) T cells. In conclusion, H. pylori shapes rather than suppresses human CD4(+) T-cell responses, and glucosylated cholesterol is a relevant bacterial component involved in this modulation. PMID:21921201

  13. Distinct diversity of the cag pathogenicity island among Helicobacter pylori strains in Japan.

    PubMed

    Azuma, Takeshi; Yamakawa, Akiyo; Yamazaki, Shiho; Ohtani, Masahiro; Ito, Yoshiyuki; Muramatsu, Atsushi; Suto, Hiroyuki; Yamazaki, Yukinao; Keida, Yoshihide; Higashi, Hideaki; Hatakeyama, Masanori

    2004-06-01

    The severity of Helicobacter pylori-related disease is correlated with the presence of a cag pathogenicity island (PAI). Genetic diversity within the cag PAI may have a modifying effect on the pathogenic potential of the infecting strain. We analyzed the complete cag PAI sequences of 11 representative Japanese strains according to their vacA genotypes and clinical effects and examined the relationship between the diversity of the cag PAI and clinical features. The cag PAI genes were divided into two major groups, a Western and a Japanese group, by phylogenetic analysis based on the entire cag PAI sequences. The predominant Japanese strains formed a Japanese cluster which was different from the cluster formed by Western strains. The diversity of the cag PAI was associated with the vacA and cagA genotypes. All strains with the s1c vacA genotype were in the Japanese cluster. In addition, all strains with the East Asian-type cagA genotype were also in the Japanese cluster. Patients infected with the Japanese-cluster strain had high-grade gastric mucosal atrophy. These results suggest that a distinct diversity of the cag PAI of H. pylori is present among Japanese strains and that this diversity may be involved in the development of atrophic gastritis and may increase the risk for gastric cancer. PMID:15184428

  14. Helicobacter pylori typing as a tool for tracking human migration

    PubMed Central

    Yamaoka, Y.

    2011-01-01

    Helicobacter pylori strains from different geographic areas exhibit clear phylogeographical differentiation; therefore, the genotypes of H. pylori strains can serve as markers for the migration of human populations. Currently, the genotypes of two virulence factors of H. pylori, cagA and vacA, and multilocus sequence typing (MLST) are widely used markers for genomic diversity within H. pylori populations. There are two types of cagA: the East Asian type and the Western type. In addition, the right end of the cag pathogenicity island is divided into five subtypes and there are distinct mosaic structures at the signal region and the middle region of vacA. Using combinations of the cagA, cag right end junction, and vacA genotypes, five major groups (East Asia type, South/Central Asia type, Iberian/Africa type and Europe type) have been defined according to geographical associations. MLST has revealed seven modern population types and six ancestral population types of H. pylori, and is a useful tool for mapping human migration patterns. Serial studies of large numbers of H. pylori strains, including strains isolated from aboriginal populations, show that MLST analysis provides more detailed information on human migration than does the analysis of human genetics. H. pylori infection is rapidly declining as a result of improvements in personal hygiene and quality of life. The molecular epidemiology of H. pylori infection has much to tell us and should be studied before it disappears entirely. PMID:19702588

  15. Distinct Diversity of the cag Pathogenicity Island among Helicobacter pylori Strains in Japan

    PubMed Central

    Azuma, Takeshi; Yamakawa, Akiyo; Yamazaki, Shiho; Ohtani, Masahiro; Ito, Yoshiyuki; Muramatsu, Atsushi; Suto, Hiroyuki; Yamazaki, Yukinao; Keida, Yoshihide; Higashi, Hideaki; Hatakeyama, Masanori

    2004-01-01

    The severity of Helicobacter pylori-related disease is correlated with the presence of a cag pathogenicity island (PAI). Genetic diversity within the cag PAI may have a modifying effect on the pathogenic potential of the infecting strain. We analyzed the complete cag PAI sequences of 11 representative Japanese strains according to their vacA genotypes and clinical effects and examined the relationship between the diversity of the cag PAI and clinical features. The cag PAI genes were divided into two major groups, a Western and a Japanese group, by phylogenetic analysis based on the entire cag PAI sequences. The predominant Japanese strains formed a Japanese cluster which was different from the cluster formed by Western strains. The diversity of the cag PAI was associated with the vacA and cagA genotypes. All strains with the s1c vacA genotype were in the Japanese cluster. In addition, all strains with the East Asian-type cagA genotype were also in the Japanese cluster. Patients infected with the Japanese-cluster strain had high-grade gastric mucosal atrophy. These results suggest that a distinct diversity of the cag PAI of H. pylori is present among Japanese strains and that this diversity may be involved in the development of atrophic gastritis and may increase the risk for gastric cancer. PMID:15184428

  16. Helicobacter pylori typing as a tool for tracking human migration.

    PubMed

    Yamaoka, Y

    2009-09-01

    Helicobacter pylori strains from different geographic areas exhibit clear phylogeographical differentiation; therefore, the genotypes of H. pylori strains can serve as markers for the migration of human populations. Currently, the genotypes of two virulence factors of H. pylori, cagA and vacA, and multilocus sequence typing (MLST) are widely used markers for genomic diversity within H. pylori populations. There are two types of cagA: the East Asian type and the Western type. In addition, the right end of the cag pathogenicity island is divided into five subtypes and there are distinct mosaic structures at the signal region and the middle region of vacA. Using combinations of the cagA, cag right end junction, and vacA genotypes, five major groups (East Asia type, South/Central Asia type, Iberian/Africa type and Europe type) have been defined according to geographical associations. MLST has revealed seven modern population types and six ancestral population types of H. pylori, and is a useful tool for mapping human migration patterns. Serial studies of large numbers of H. pylori strains, including strains isolated from aboriginal populations, show that MLST analysis provides more detailed information on human migration than does the analysis of human genetics. H. pylori infection is rapidly declining as a result of improvements in personal hygiene and quality of life. The molecular epidemiology of H. pylori infection has much to tell us and should be studied before it disappears entirely. PMID:19702588

  17. Protection against Helicobacter pylori infection in mice by intragastric vaccination with H. pylori antigens is achieved using a non-toxic mutant of E. coli heat-labile enterotoxin (LT) as adjuvant.

    PubMed

    Marchetti, M; Rossi, M; Giannelli, V; Giuliani, M M; Pizza, M; Censini, S; Covacci, A; Massari, P; Pagliaccia, C; Manetti, R; Telford, J L; Douce, G; Dougan, G; Rappuoli, R; Ghiara, P

    1998-01-01

    We have previously shown that infection of mice with H. pylori can be prevented by oral immunization with H. pylori antigens given together with E. coli heat-labile enterotoxin (LT) as adjuvant. Since LT cannot be used in humans because of its unacceptable toxicity, we investigated whether protection of mice could be achieved by co-administration of antigens with non-toxic LT mutants. Here we show that CD1/SPF mice are protected against infection after oral vaccination with either purified H. pylori antigens (native and recombinant VacA, urease and CagA), or whole-cell vaccine formulations, given together with the non-toxic mutant LTK63 as a mucosal adjuvant. Furthermore we show that such protection is antigen-specific since immunization with recombinant or native VacA plus LTK63 conferred protection against infection by an H. pylori Type I strain, which expresses VacA, but not against challenge with a Type II strain which is not able to express this antigen. These results show that: (1) protection against H. pylori can be achieved in the mouse model of infection using subunit recombinant constructs plus non-toxic mucosal adjuvants; and (2) this mouse model is an useful tool in testing H. pylori vaccine formulations for eventual use in humans. PMID:9607006

  18. Preparation and characterization of cross-linked collagen-phospholipid polymer hybrid gels.

    PubMed

    Nam, Kwangwoo; Kimura, Tsuyoshi; Kishida, Akio

    2007-01-01

    2-methacryloyloxyethyl phosphorylcholine (MPC)-immobilized collagen gel was developed. Using 1-ethyl-3-(3-dimethyl aminopropyl)-1-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), we cross-linked a collagen film in 2-morpholinoethane sulfonic acid (MES) buffer (EN gel). EN gel was prepared under both pH 4.5 and pH 9.0 in order to observe changes in cross-linking ability. To cross-link MPC to collagen gel, poly(MPC-co-methacrylic acid) (PMA) having a carboxyl group side chain was chosen. E/N gel was added to the MES buffer having pre-NHS activated PMA to make MPC-immobilized collagen gel (MiC gel). MiC gel was prepared under both acidic and alkaline conditions to observe the changes in the cross-linking ability of PMA. X-ray photoelectron spectroscopy showed that the PMA was cross-linked with collagen under both acidic and alkaline conditions. Differential scanning calorimetry (DSC) results showed that the shrinkage temperature increased for the MiC gels and that the increase would be greater for the MiC gel prepared under alkaline conditions. The data showed that swelling would be less when the MiC gel was prepared under alkaline conditions. The biodegradation caused by collagenase was suppressed for the MiC gel prepared under alkaline conditions due to stable inter- and intrahelical networks. PMID:16959313

  19. Helicobacter pylori γ-glutamyl transpeptidase and vacuolating cytotoxin promote gastric persistence and immune tolerance

    PubMed Central

    Oertli, Mathias; Noben, Manuel; Engler, Daniela B.; Semper, Raphaela P.; Reuter, Sebastian; Maxeiner, Joachim; Gerhard, Markus; Taube, Christian; Müller, Anne

    2013-01-01

    Infection with the gastric bacterial pathogen Helicobacter pylori is typically contracted in early childhood and often persists for decades. The immunomodulatory properties of H. pylori that allow it to colonize humans persistently are believed to also account for H. pylori’s protective effects against allergic and chronic inflammatory diseases. H. pylori infection efficiently reprograms dendritic cells (DCs) toward a tolerogenic phenotype and induces regulatory T cells (Tregs) with highly suppressive activity in models of allergen-induced asthma. We show here that two H. pylori virulence determinants, the γ-glutamyl transpeptidase GGT and the vacuolating cytotoxin VacA, contribute critically and nonredundantly to H. pylori’s tolerizing effects on murine DCs in vitro and in vivo. The tolerance-promoting effects of both factors are independent of their described suppressive activity on T cells. Isogenic H. pylori mutants lacking either GGT or VacA are incapable of preventing LPS-induced DC maturation and fail to drive DC tolerization as assessed by induction of Treg properties in cocultured naive T cells. The Δggt and ΔvacA mutants colonize mice at significantly reduced levels, induce stronger T-helper 1 (Th1) and T-helper 17 (Th17) responses, and/or trigger more severe gastric pathology. Both factors promote the efficient induction of Tregs in vivo, and VacA is required to prevent allergen-induced asthma. The defects of the Δggt mutant in vitro and in vivo are phenocopied by pharmacological inhibition of the transpeptidase activity of GGT in all readouts. In conclusion, our results reveal the molecular players and mechanistic basis for H. pylori-induced immunomodulation, promoting persistent infection and conferring protection against allergic asthma. PMID:23382221

  20. Differences in Virulence Markers between Helicobacter pylori Strains from Iraq and Those from Iran: Potential Importance of Regional Differences in H. pylori-Associated Disease▿

    PubMed Central

    Hussein, Nawfal R.; Mohammadi, Marjan; Talebkhan, Yeganeh; Doraghi, Masoumeh; Letley, Darren P.; Muhammad, Merdan K.; Argent, Richard H.; Atherton, John C.

    2008-01-01

    Helicobacter pylori causes peptic ulceration and gastric adenocarcinoma; the latter is common in Iran but not in Iraq. We hypothesized that more virulent H. pylori strains may be found in Iran than in Iraq and so compared established and newly described virulence factors in strains from these countries. We studied 59 unselected dyspeptic patients from Iran and 49 from Iraq. cagA was found in similar proportions of strains from both countries (76% in Iran versus 71% in Iraq) and was significantly associated with peptic ulcer disease in Iraq (P ≤ 0.01) but not in Iran. cagA alleles encoding four or more tyrosine phosphorylation motifs were found in 12% of the Iranian strains but none of the Iraqi strains (P = 0.02). There were no significant differences in the vacA signal-, middle-, or intermediate-region types between Iranian and Iraqi strains. Among the strains from Iran, vacA genotypes showed no specific peptic ulcer associations, but among the strains from Iraq, vacA i1 strains were associated with gastric ulcer (P ≤ 0.02), mimicking their previously demonstrated association with gastric cancer in Iran. dupA was found in similar proportions of Iranian and Iraqi strains (38% and 32%, respectively) and was associated with peptic ulceration in Iraqi patients (P ≤ 0.01) but not Iranian patients. H. pylori strains from Iraq and Iran possess virulence factors similar to those in Western countries. The presence of cagA with more phosphorylation motifs in Iranian strains may contribute to the higher incidence of gastric cancer. However, the association between strain virulence markers and disease in Iraq but not Iran suggests that other host and environmental factors may be more important in the disease-prone Iranian population. PMID:18353934

  1. Analysis of virulence factors of Helicobacter pylori isolated from a Vietnamese population

    PubMed Central

    2009-01-01

    Background The incidence of gastric cancer differs among countries in Asia, and it has been suggested that virulence factors associated with Helicobacter pylori are partly responsible. The aim of this study was to investigate several genetic factors regarded as virulence or molecular epidemiologic markers in H. pylori isolates from Vietnamese subjects. Results The cagA, vacA and cag right-end junction genotypes of 103 H. pylori strains from Vietnam (54 from Hanoi and 49 from Ho Chi Minh) were determined by PCR and sequencing. Three types of deletion in the region located upstream of the cagA Glu-Pro-Ile-Tyr-Ala (EPIYA) repeat region were identified: the 39-bp deletion type, the 18-bp deletion type, and the no-deletion type. The majority of strains studied (77%; 80/103) had the 18-bp deletion irrespective of geographical location in the country or clinical outcome. All of the 39-bp and 18-bp deletion-type strains possessed the East Asian type cagA repeat region. The type II cag right-end junction genotype was predominant (84%). The vacA m1 genotype was significantly more common in strains isolated in Hanoi, where the incidence of gastric cancer is higher, than in strains from Ho Chi Minh. Conclusion Pre-EPIYA-region typing of the cagA gene could provide a new genetic marker of H. pylori genomic diversity. Our data support the hypothesis that vacA m1 is closely associated with gastric carcinogenesis. PMID:19698173

  2. Resistance to clarithromycin and genotypes in Helicobacter pylori strains isolated in Sicily.

    PubMed

    Fasciana, Teresa; Calà, Cinzia; Bonura, Celestino; Di Carlo, Enza; Matranga, Domenica; Scarpulla, Giuseppe; Manganaro, Michele; Camilleri, Salvatore; Giammanco, Anna

    2015-11-01

    The resistance of Helicobacter pylori strains to clarithromycin is increasing in several developed countries and their association with a genetic pattern circulation has been variously explained as related to different geographical areas. In this study we have reported: the prevalence of the resistance of H. pylori, isolated in Sicily, to clarithromycin; the principal point of mutation associated with this resistance; and the more frequent association between resistance to clarithromycin and cagA, the EPIYA motif, and the vacA and oipA genes. Resistance to clarithromycin was detected in 25% of cases, the main genetic mutation involved being A2143G. The cagA gene was present in 48% of cases and the distribution of the EPIYA motif was: ABC in 35 cases; ABCC in 8 cases; ABCCC in 2 cases; ABC-ABCC in 2 cases; and ABC-ABCC-ABCCC in 1 case. Regarding the vacA allele, an s1i1m1 combination was detected in 35% of cases, s1i1m2 in 12 %, s1i2m2 in 12%, s2i2m2 in 40%, and a double s1m1-m2 mosaic in 1% of cases. The status of the oipA gene was 'off' in 45% of cases and 'on' in 55%. Resistance to clarithromycin was found to be high in Sicily, but no correlation was found among resistance to clarithromycin, the vacA gene and oipA status; a higher correlation was observed between resistant strains and cagA-negative strains. PMID:26338221

  3. Helicobacter pylori γ-glutamyl transpeptidase and vacuolating cytotoxin promote gastric persistence and immune tolerance.

    PubMed

    Oertli, Mathias; Noben, Manuel; Engler, Daniela B; Semper, Raphaela P; Reuter, Sebastian; Maxeiner, Joachim; Gerhard, Markus; Taube, Christian; Müller, Anne

    2013-02-19

    Infection with the gastric bacterial pathogen Helicobacter pylori is typically contracted in early childhood and often persists for decades. The immunomodulatory properties of H. pylori that allow it to colonize humans persistently are believed to also account for H. pylori's protective effects against allergic and chronic inflammatory diseases. H. pylori infection efficiently reprograms dendritic cells (DCs) toward a tolerogenic phenotype and induces regulatory T cells (Tregs) with highly suppressive activity in models of allergen-induced asthma. We show here that two H. pylori virulence determinants, the γ-glutamyl transpeptidase GGT and the vacuolating cytotoxin VacA, contribute critically and nonredundantly to H. pylori's tolerizing effects on murine DCs in vitro and in vivo. The tolerance-promoting effects of both factors are independent of their described suppressive activity on T cells. Isogenic H. pylori mutants lacking either GGT or VacA are incapable of preventing LPS-induced DC maturation and fail to drive DC tolerization as assessed by induction of Treg properties in cocultured naive T cells. The Δggt and ΔvacA mutants colonize mice at significantly reduced levels, induce stronger T-helper 1 (Th1) and T-helper 17 (Th17) responses, and/or trigger more severe gastric pathology. Both factors promote the efficient induction of Tregs in vivo, and VacA is required to prevent allergen-induced asthma. The defects of the Δggt mutant in vitro and in vivo are phenocopied by pharmacological inhibition of the transpeptidase activity of GGT in all readouts. In conclusion, our results reveal the molecular players and mechanistic basis for H. pylori-induced immunomodulation, promoting persistent infection and conferring protection against allergic asthma. PMID:23382221

  4. [Milk and dairy products: evidence and recommendations in health and disease].

    PubMed

    Milke-García, María Del Pilar; Arroyo, Pedro

    2016-09-01

    El presente suplemento tiene como propósito mostrar el contexto y una guía clínica sobre el consumo y papel de la leche de vaca en la alimentación. El contenido considera el papel de la leche y productos lácteos en diferentes estados fisiológicos, etapas de vida y patologías. Se basa en la mejor evidencia científica disponible y está dirigido a profesionales de la salud de diferentes especialidades. PMID:27603880

  5. Vestiges of an Ordovician west-vergent thin-skinned Ocloyic thrust belt in the Argentine Precordillera, southern Central Andes

    NASA Astrophysics Data System (ADS)

    Thomas, William A.; Astini, Ricardo A.

    2007-08-01

    Collision of the down-going, Laurentia-derived Argentine Precordillera terrane with the Gondwanan margin drove the Ordovician Ocloyic orogeny, including subduction volcanism, metamorphism, and top-to-west shearing east of the Precordillera. In the Precordillera, above passive-margin carbonates (Lower Ordovician San Juan Limestone and older carbonates), a Middle to Upper Ordovician westward-prograding synorogenic clastic wedge of black shale (Gualcamayo Shale) and coarser clastic sediment (Las Vacas Conglomerate and Trapiche Formation) fills a peripheral foreland basin. New research has identified vestiges of a west-directed thin-skinned Ocloyic foreland thrust belt that has been fragmented by east-directed Andean thrusting. The El Corral thrust sheet, with hanging-wall detachment in the San Juan Limestone, extends over a west-directed footwall frontal ramp and extensive flat to low-angle footwall cutoff in the Gualcamayo and Las Vacas formations. Las Vacas conglomerates in the footwall include olistoliths (10-m scale) exclusively of San Juan Limestone and Gualcamayo Shale; the beds in some olistoliths are folded. The advancing El Corral thrust sheet successively supplied and overrode the stratigraphically restricted olistoliths. In the El Corral footwall, tight west-vergent folds and faults within an anticlinorium in the San Juan Limestone and Gualcamayo Shale suggest a deeper (unexposed) thrust fault, the Los Celestitos fault. West of the anticlinorium, easterly dip (restored to remove Andean deformation) beneath an angular unconformity between Las Vacas and Trapiche beds is consistent geometrically with the trailing limb of a west-vergent fault-propagation anticline in the hanging wall of the subsurface Los Celestitos fault. The same angular unconformity truncates the El Corral fault and hanging-wall strata. In the Trapiche Formation, contrasting sedimentary facies from sandy turbidites westward to limestone-clast megabeds and olistoliths suggest another frontal

  6. Prevalence and Genotypes of Helicobacter pylori in Gastric Biopsy Specimens from Patients with Gastroduodenal Pathologies in the Cukurova Region of Turkey▿

    PubMed Central

    Nagiyev, Togrul; Yula, Erkan; Abayli, Bahri; Koksal, Fatih

    2009-01-01

    The effects of Helicobacter pylori genotypes on clinical prognosis in the Cukurova region of Turkey were investigated by PCR. The prevalence of type I strains carrying the s1c allele, unlike in neighboring regions and countries, was found to be significantly higher in patients with gastritis and/or gastric ulcers (P = 0.001), and that of type I strains carrying the s1a allele was found to be significantly higher in patients with duodenal ulcers (P < 0.001). The cagA gene was strongly associated with the more virulent vacA genotypes (P < 0.001). PMID:19846654

  7. Virulence Genes and Neutral DNA Markers of Helicobacter pylori Isolates from Different Ethnic Communities of West Bengal, India

    PubMed Central

    Datta, Simanti; Chattopadhyay, Santanu; Balakrish Nair, G.; Mukhopadhyay, Asish K.; Hembram, Jabaranjan; Berg, Douglas E.; Rani Saha, Dhira; Khan, Asis; Santra, Amal; Bhattacharya, S. K.; Chowdhury, Abhijit

    2003-01-01

    Virulence-associated genes and neutral DNA markers of Helicobacter pylori strains from the Santhal and Oroan ethnic minorities of West Bengal, India, were studied. These people have traditionally been quite separate from other Indians and differ culturally, genetically, and linguistically from mainstream Bengalis, whose H. pylori strains have been characterized previously. H. pylori was found in each of 49 study participants, although none had peptic ulcer disease, and was cultured from 31 of them. All strains carried the cag pathogenicity island and potentially toxigenic s1 alleles of vacuolating cytotoxin gene (vacA) and were resistant to at least 8 μg of metronidazole per ml. DNA sequence motifs in vacA mid-region m1 alleles, cagA, and an informative insertion or deletion motif next to cagA from these strains were similar to those of strains from ethnic Bengalis. Three mobile elements, IS605, IS607, and ISHp608, were present in 29, 19, and 10%, respectively, of Santhal and Oroan strains, which is similar to their prevalence in Bengali H. pylori. Thus, there is no evidence that the gene pools of H. pylori of these ethnic minorities differ from those of Bengalis from the same region. This relatedness of strains from persons of different ethnicities bears on our understanding of H. pylori transmission between communities and genome evolution. PMID:12904384

  8. Virulence genes and neutral DNA markers of Helicobacter pylori isolates from different ethnic communities of West Bengal, India.

    PubMed

    Datta, Simanti; Chattopadhyay, Santanu; Balakrish Nair, G; Mukhopadhyay, Asish K; Hembram, Jabaranjan; Berg, Douglas E; Rani Saha, Dhira; Khan, Asis; Santra, Amal; Bhattacharya, S K; Chowdhury, Abhijit

    2003-08-01

    Virulence-associated genes and neutral DNA markers of Helicobacter pylori strains from the Santhal and Oroan ethnic minorities of West Bengal, India, were studied. These people have traditionally been quite separate from other Indians and differ culturally, genetically, and linguistically from mainstream Bengalis, whose H. pylori strains have been characterized previously. H. pylori was found in each of 49 study participants, although none had peptic ulcer disease, and was cultured from 31 of them. All strains carried the cag pathogenicity island and potentially toxigenic s1 alleles of vacuolating cytotoxin gene (vacA) and were resistant to at least 8 micro g of metronidazole per ml. DNA sequence motifs in vacA mid-region m1 alleles, cagA, and an informative insertion or deletion motif next to cagA from these strains were similar to those of strains from ethnic Bengalis. Three mobile elements, IS605, IS607, and ISHp608, were present in 29, 19, and 10%, respectively, of Santhal and Oroan strains, which is similar to their prevalence in Bengali H. pylori. Thus, there is no evidence that the gene pools of H. pylori of these ethnic minorities differ from those of Bengalis from the same region. This relatedness of strains from persons of different ethnicities bears on our understanding of H. pylori transmission between communities and genome evolution. PMID:12904384

  9. Isotopic, Chemical and Mineralogical Investigation's of Extraterrestrial Materials

    NASA Technical Reports Server (NTRS)

    Lugmair, G. W.

    2003-01-01

    During the grant period we have concentrated on the following main topics: 1. Enstatite meteorites and original heterogeneity of Mn-53 distribution in the solar nebula. We have completed our studies of the enstatite chondrites. 2. Processes of planetary differentiation. We have completed our study of silicate clasts from the mesosiderite Vaca Muerta and found that the global Mn/Cr fractionation event that established mantle source reservoirs on the parent body of the Vaca Muerta silicate clasts occurred approx. 2 Ma after a similar event on the howardite-eucrite-diogenite (HED) parent body. 3. Carbonaceous chondrites. Much effort has been devoted during the last three years to the investigation of this important class of meteorites. 4. Early solar system timescales. Based on the studies of the Mn-53 - Cr-53 isotope system in various meteorites and using results obtained with other isotope chronometers we constructed an absolute time-scale for events in the early solar system. 5.Unusual meteorites. We have studied the anomalous pallasite Eagle Station. 6. The chromium isotopic composition as a tracer for extraterrestrial material on Earth. Based on the observed difference in the Cr-53/Cr-52 ratios between Earth and the other solar system objects we developed a method for detecting cosmic materials on Earth using the Cr-53/Cr-52 ratio as a tracer.

  10. Preliminary design of a special casing joint for a well equipped twin horizontal drainholes in the Oxnard field

    SciTech Connect

    Not Available

    1993-12-31

    The Oxnard field is presently under production,with a typical average monthly oil production of about 70,000 B, of which the Vaca Tar sand represents more than half.It is Unitized and operated under cyclic steam injection.The hot Tar and produced water are lifted to the surface with rod pumps equipped for injection of a diluent. The produced WOR is about 2.5 and the GOR is about 150 scf/B. The Vaca Tar sand originally contained about 400 million STB. The estimated recoverable reserve under full-scale cyclic steam injection is 100 to 120 Million STB. Under steamflood, it might reach 240 million STB. The objectives of this field test are: (1) increase well productivity by using a vertical well equipped with twin horizontal drainholes, each of about 1,000 ft. reach; (2) maximize the well draw-down by locating the horizontal wells near the base of the sand layer; (3) reduce capital cost by using twin drainholes connected to the same vertical cased well; (4) reduce operating expenses by eliminating the need for a service rig to pull-out the rods and pump before each steam injection cycle; and (5) be adaptable to other operating modes.

  11. Helicobacter pylori transiently in the mouth may participate in the transmission of infection.

    PubMed

    Silva, Denise G; Tinoco, Eduardo M B; Rocha, Gifone A; Rocha, Andreia Maria Camargos; Guerra, Juliana B; Saraiva, Ivan E B; Queiroz, Dulciene M M

    2010-08-01

    Helicobacter pylori infection is associated with peptic ulcer and gastric carcinoma. The oral cavity may be a reservoir for H. pylori; however, the results of studies on this subject are controversial. We employed single-step and nested polymerase chain reactions (PCR) to detect the presence of the vacA, ureA and 16S rDNA genes of H. pylori in the stomach, saliva and dental plaque of 30 subjects. The results were confirmed by sequencing. Nested 16S rDNA and ureA amplification was achieved in 80% of gastric, 30% of saliva and 20% of dental plaque specimens. Sequencing of 10, seven and four 16S rDNA products from stomach, saliva and dental plaque, respectively, showed > 99% identity with H. pylori. Sequencing of the other four oral cavity PCR products showed similarity with Campylobacter and Wolinella species. Additionally, the vacA genotype identified in the samples of different sites was the same within a given subject.H. pylori may be found in the oral cavity of patients with gastric infection, thus it could be a source of transmission. However, results obtained with detection methods based only on PCR should be interpreted with caution because other microorganisms that are phylogenetically very close to H. pylori are also present in the mouth. PMID:20835612

  12. Immune responses to Helicobacter pylori infection

    PubMed Central

    Moyat, Mati; Velin, Dominique

    2014-01-01

    Helicobacter pylori (H. pylori) infection is one of the most common infections in human beings worldwide. H. pylori express lipopolysaccharides and flagellin that do not activate efficiently Toll-like receptors and express dedicated effectors, such as γ-glutamyl transpeptidase, vacuolating cytotoxin (vacA), arginase, that actively induce tolerogenic signals. In this perspective, H. pylori can be considered as a commensal bacteria belonging to the stomach microbiota. However, when present in the stomach, H. pylori reduce the overall diversity of the gastric microbiota and promote gastric inflammation by inducing Nod1-dependent pro-inflammatory program and by activating neutrophils through the production of a neutrophil activating protein. The maintenance of a chronic inflammation in the gastric mucosa and the direct action of virulence factors (vacA and cytotoxin-associated gene A) confer pro-carcinogenic activities to H. pylori. Hence, H. pylori cannot be considered as symbiotic bacteria but rather as part of the pathobiont. The development of a H. pylori vaccine will bring health benefits for individuals infected with antibiotic resistant H. pylori strains and population of underdeveloped countries. PMID:24914318

  13. Upwelling-triggered near-geostrophic recirculation in an equatorward facing embayment

    NASA Astrophysics Data System (ADS)

    Moraga-Opazo, Julio; Valle-Levinson, Arnoldo; Ramos, Marcel; Pizarro-Koch, Matías

    2011-12-01

    Underway current velocity profiles were combined with hydrographic profiles at the entrance to Tongoy Bay, an equatorward facing bay in north-central Chile, with the objective of determining its exchange hydrodynamics. To the west, Tongoy Bay is bounded by Lengua de Vaca Point, a ˜6 km-long northward protruding peninsula. Observations were obtained during three surveys (April 2005, December 2005, May 2009) along cross-bay transects for at least one full day. During the surveys, winds were upwelling-favorable and displayed diurnal variations. Non-tidal (tidally averaged) flows showed a consistent clockwise or southern hemisphere cyclonic, recirculation during the three surveys. This recirculation was likely part of a cyclonic gyre (10-20 km in diameter), not entirely resolved by the surveys, and formed by flow separation off Lengua de Vaca Point. Estimates of the baroclinic pressure gradient, combined with analytical solutions of density-driven and wind-driven flows, indicated that the recirculation in Tongoy Bay was nearly in geostrophic balance. An ageostrophic contribution to the dynamics was related to frictional effects derived from local upwelling-favorable winds. A linear superposition of the analytically derived density-driven and wind-driven exchange resulted in a flow pattern that resembled the observed net exchange flows at the bay mouth.

  14. Molecular analysis of Helicobacter pylori virulent-associated genes in hepatobiliary patients

    PubMed Central

    Boonyanugomol, Wongwarut; Chomvarin, Chariya; Sripa, Banchob; Chau-in, Siri; Pugkhem, Ake; Namwat, Wises; Wongboot, Warawan; Khampoosa, Bandit

    2012-01-01

    Objectives The Helicobacter pylori virulence-associated genes in hepatobiliary patients, including vacA, iceA, babA2, cagA and cagE, have not been reported. The aim of this study was to investigate these genes and the association of those and the clinical outcomes in hepatobiliary diseases. Methods Eighty H. pylori-PCR-positive cases were obtained from hepatobiliary patients, representing both cholangiocarcinoma (CCA) (n = 58) and cholelithiasis (n = 22). The diversity of virulence genes was examined by polymerase chain reaction and DNA sequencing. Phylogenetic analysis of cagA was determined using the maximum parsimony method. Results The vacAs1a + c/m1, iceA1 and babA2 genes were the most predominant genotypes in both CCA and cholelithiasis patients. The cagA and cagE genes were found significantly more frequently in patients with CCA than those with cholelithiasis (P < 0.05). The cagA positive samples were the Western-type cagA and showed that almost all of the detected sequences in Thai hepatobiliary and Thai gastric cancer patients were classified in the same cluster but separated from the cluster of Japan and other countries. Conclusions The cagA and cagE genes may be associated in the pathogenesis of hepatobiliary diseases, especially of CCA. Besides the bacterial variation, other host factors may be involved in the pathogenesis of hepatobiliary cancer. PMID:23043664

  15. Helicobacter pylori infection in children: should it be carefully assessed?

    PubMed

    Ortiz-Princz, D; Daoud, G; Salgado-Sabel, A; Cavazza, M E

    2016-05-01

    The prevalence of H. pylori infection, mainly acquired during childhood and may be persisting throughout life, has been found high in developing countries; this high prevalence is related to low socioeconomic status. The persistence of bacterium exposure is related to gastritis and other severe complications including peptic ulcer, lymphoma MALT and gastric cancer, which are rarely present in the pediatric age due to a lower inflammatory and immunological response. Virulence factors, host gastric mucosal factors, and the natural environment of patients are associated with the clinical outcome of H. pylori infection. The main bacterial virulence factors include adhesins (BabA, SabA), vacuolating cytotoxin VacA, and the products of the cag pathogenicity island (cag PAI). There are geographic differences between cagA, vacA status and H. pylori related diseases. The main criteria to evaluate H. pylori infection in children are gastrointestinal and extra gastrointestinal manifestations related to H. pylori infection, familial history of gastric cancer, peptic ulcer, lymphoma MALT, symptomatic children living in high prevalence regions, and immigrant or adopted children in developed countries. Early detection of H. pylori and its virulence factors, in addition to effective methods of eradication associated with prevention programs, may lead to the decrease of H. pylori incidence and gastritis, especially in endemic high-risk regions. The early assessment in children may prevent further severe complications in adulthood. PMID:27212173

  16. Sulfuric acid measurements in the exhaust plume of a jet aircraft in flight: Implications for the sulfuric acid formation efficiency

    NASA Astrophysics Data System (ADS)

    Curtius, J.; Arnold, F.; Schulte, P.

    2002-04-01

    Sulfuric acid concentrations were measured in the exhaust plume of a B737-300 aircraft in flight. The measurements were made onboard of the German research aircraft Falcon using the Volatile Aerosol Component Analyzer (VACA). The VACA measures total H2SO4, which is the sum of gaseous H2SO4 and aerosol H2SO4. Measurements took place at distances of 25-200 m behind the B737 corresponding to plume ages of about 0.1-1 seconds. The fuel sulfur content (FSC) of the fuel burned by the B737 engines was alternatively 2.6 and 56 mg sulfur per kilogram fuel (ppmm). H2SO4 concentrations measured in the plume for the 56 ppmm sulfur case were up to ~600 pptv. The average concentration of H2SO4 measured in the ambient atmosphere outside the aircraft plume was 88 pptv, the maximum ambient atmospheric H2SO4 was ~300 pptv. Average efficiencies ɛΔCO2 = 3.3 +/- 1.8% and ɛΔT = 2.9 +/- 1.6% for fuel sulfur conversion to sulfuric acid were inferred when relating the H2SO4 data to measurements of the plume tracers ΔCO2 and ΔT.

  17. Therapeutic intragastric vaccination against Helicobacter pylori in mice eradicates an otherwise chronic infection and confers protection against reinfection.

    PubMed

    Ghiara, P; Rossi, M; Marchetti, M; Di Tommaso, A; Vindigni, C; Ciampolini, F; Covacci, A; Telford, J L; De Magistris, M T; Pizza, M; Rappuoli, R; Del Giudice, G

    1997-12-01

    Chronic infection of the gastroduodenal mucosae by the gram-negative spiral bacterium Helicobacter pylori is responsible for chronic active gastritis, peptic ulcers, and gastric cancers such as adenocarcinoma and low-grade gastric B-cell lymphoma. The success of eradication by antibiotic therapy is being rapidly hampered by the increasing occurrence of antibiotic-resistant strains. An attractive alternative approach to combat this infection is represented by the therapeutic use of vaccines. In the present work, we have exploited the mouse model of persistent infection by mouse-adapted H. pylori strains that we have developed to assess the feasibility of the therapeutic use of vaccines against infection. We report that an otherwise chronic H. pylori infection in mice can be successfully eradicated by intragastric vaccination with H. pylori antigens such as recombinant VacA and CagA, which were administered together with a genetically detoxified mutant of the heat-labile enterotoxin of Escherichia coli (referred to as LTK63), in which the serine in position 63 was replaced by a lysine. Moreover, we show that therapeutic vaccination confers efficacious protection against reinfection. These results represent strong evidence of the feasibility of therapeutic use of VacA- or CagA-based vaccine formulations against H. pylori infection in an animal model and give substantial preclinical support to the application of this kind of approach in human clinical trials. PMID:9393788

  18. V Olimpíada Brasileira de Astronomia

    NASA Astrophysics Data System (ADS)

    Villas da Rocha, J. F.; Canalle, J. B. G.; Wuesnche, C. A.; de Medeiros, J. R., Silva, A. V. R.; Lavouras, D. F.; Dottori, H. A.; Maia, M. A. G.; Vieira Martins, R.; Poppe, P. C. R.

    2003-08-01

    Neste trabalho apresentamos os resultados da V Olimpíada Brasileira de Astronomia, a qual ocorreu em 11/05/2002 em todos os estabelecimentos de ensino fundamental ou médio previamente cadastrados. Participaram do evento 60.338 alunos distribuídos por 1469 escolas pertencentes a todos os Estados brasileiros. Uma equipe de 5 alunos foi escolhida para representar o Brasil na VII Olimpíada Internacional de Astronomia que ocorreu na Rússia em 2002 e dois de nossos alunos ganharam a medalha de bronze naquele evento.

  19. Classification of mafic clasts from mesosiderites - Implications for endogenous igneous processes

    NASA Technical Reports Server (NTRS)

    Rubin, Alan E.; Mittlefehldt, David W.

    1992-01-01

    Results are presented from an analysis of 13 igneous pebbles from the Vaca Muerta, EET87500, and Bondoc mesosiderites, using electron microprobe and instrumental neutron activation techniques. These data, combined with literature data on compositions of 43 mesosiderite clasts were used to compile a classification scheme for the various types of mafic silicate clasts that occur in mesosiderites. These clasts were classified into five principal groups: (1) polygenic and monogenic cumulates (30 percent); (2) polygenic basalts (30 percent); (3) quench-textured rocks, comprising two compositional subgroups (those which resemble basaltic eucrites (5 percent), and those which resemble cumulate eucrites (2 percent)); (4) monogenic basalts (11 percent); and (5) ultramafic rocks, consisting mainly of large crystals of orthopyroxene (9 percent) or olivine (4 percent). The conditions under which these clasts were formed are discussed.

  20. Olivines and olivine coronas in mesosiderites

    NASA Technical Reports Server (NTRS)

    Nehru, C. E.; Zucker, S. M.; Harlow, G. E.; Prinz, M.

    1980-01-01

    The paper presents a study of olivines and their surrounding coronas in mesosiderites texturally and compositionally using optical and microprobe methods. Olivine composition ranges from Fo(58-92) and shows no consistent pattern of distribution within and between mesosiderites; olivine occurs as large single crystals or as partially recrystallized mineral clasts, except for two lithic clasts. These are Emery and Vaca Muerta, and both are shock-modified olivine orthopyroxenites. Fine-grained coronas surround olivine, except for those in impact-melt group mesosiderites and those without tridymite in their matrices. Coronas consist largely of orthopyroxene, plagioclase, clinopyroxene, chromite, merillite, and ilmenite, and are similar to the matrix, but lack metal and tridymite. Texturally the innermost parts of the corona can be divided into three stages of development: (1) radiating acicular, (2) intermediate, and (3) granular.

  1. Helicobacter pylori infection in Japan

    PubMed Central

    Shiota, Seiji; Murakawi, Kazunari; Suzuki, Rumiko; Fujioka, Toshio; Yamaoka, Yoshio

    2013-01-01

    The prevalence of Helicobacter pylori infection is gradually decreasing in Japan. On the main island of Japan, nearly all H. pylori isolates possess cagA and vacA with strong virulence. However, less virulent H. pylori strains are frequently found in Okinawa where cases of gastric cancer are the lowest in Japan. Eradication therapy for peptic ulcer, idiopathic thrombocytopenic purpura, gastric mucosa-associated lymphoid tissue lymphoma and early gastric cancer after endoscopic resection has been approved by the Japanese national health insurance system. However, the Japanese Society for Helicobacter Research recently stated that all ‘H. pylori infection’ was considered as the indication for eradication irrespective of the background diseases. To eliminate H. pylori in Japan, the Japanese health insurance system should approve the eradication of all H. pylori infections. PMID:23265147

  2. Historical descriptions of some soils and landscapes of Texas

    NASA Astrophysics Data System (ADS)

    Schulze, Darrell G.

    Europeans explorers, immigrants, and travelers have been crisscrossing Texas for almost 5 centuries, recording their observations of soils and landscapes through the lens of their own times. In the early 16th century, Cabeza de Vaca was struck by how the natives among whom he lived used soil as a part of their diet. In the 17th century, as a member of the La Salle expedition to Texas, Henri Joutel described the soils and landscapes he saw in considerable detail, perhaps with an eye to possible future French settlement. To 19th century immigrants, the soil was the source of their future wealth, but also, so they thought, of the source of the various illnesses that inflicted them. With their distinctive micro-topography and large cracks when dry, Vertisols have elicited some of the most interesting early descriptions of Texas soils.

  3. Cytotoxic Action of Serratia marcescens Hemolysin on Human Epithelial Cells

    PubMed Central

    Hertle, Ralf; Hilger, Martina; Weingardt-Kocher, Sandra; Walev, Iwan

    1999-01-01

    Incubation of human epithelial cells with nanomolar concentrations of chromatographically purified Serratia marcescens hemolysin (ShlA) caused irreversible vacuolation and subsequent lysis of the cells. Vacuolation differed from vacuole formation by Helicobacter pylori VacA. Sublytic doses of ShlA led to a reversible depletion of intracellular ATP. Restoration to the initial ATP level was presumably due to the repair of the toxin damage and was inhibited by cycloheximide. Pores formed in epithelial cells and fibroblasts without disruption of the plasma membrane, and the pores appeared to be considerably smaller than those observed in artificial lipid membranes and in erythrocytes and did not allow the influx of propidium iodide or trypan blue. All cytotoxic effects induced by isolated recombinant ShlA were also obtained with exponentially growing S. marcescens cells. The previously suggested role of the hemolysin in the pathogenicity of S. marcescens is supported by these data. PMID:9916096

  4. Comparison of Storage Capacity and Sedimentation Trends of Lago Guayabal, Puerto Rico-December 2001 and October 2006

    USGS Publications Warehouse

    Soler-López, Luis R.

    2008-01-01

    Lago Guayabal dam is located on the Rio Jacaguas in the municipality of Villalba in southern Puerto Rico, about 4 kilometers north of the town of Juana Diaz and about 5 kilometers south of Villalba (fig. 1). The dam is owned and operated by the Puerto Rico Electric Power Authority (PREPA) and was constructed in 1913 for the irrigation of croplands in the southern coastal plains of Puerto Rico. The reservoir impounds the waters of the Rio Jacaguas and those of the Rio Toa Vaca, when the Toa Vaca dam overflows or releases water. The reservoir has a drainage area of 53.8 square kilometers. The dam is a concrete gravity structure with a normal pool (at top of flashboards) elevation of 103.94 meters above mean sea level (Puerto Rico Electric Power Authority, 1988). During October 2006, the U.S. Geological Survey (USGS), Caribbean Water Science Center, in cooperation with the Puerto Rico Aqueduct and Sewer Authority (PRASA) conducted a bathymetric survey of Lago Guayabal to update the reservoir storage capacity and actualize the reservoir sedimentation rate by comparing the 2006 data with the previous 2001 bathymetric survey results. The purpose of this report is to describe and document the USGS sedimentation survey conducted at Lago Guayabal during October 2006, including the methods used to update the reservoir storage capacity, sedimentation rates, and areas of substantial sediment accumulation since December 2001. The Lago Guayabal sedimentation history up to 2001 was published by the USGS in 2003 (Soler-Lopez, 2003); therefore, this report focuses on the comparison between the 2001 and current bathymetric surveys of Lago Guayabal.

  5. Serological response to Helicobacter pylori infection among Latin American populations with contrasting risks of gastric cancer.

    PubMed

    Camargo, M Constanza; Beltran, Mauricio; Conde-Glez, Carlos J; Harris, Paul R; Michel, Angelika; Waterboer, Tim; Carolina Flórez, Astrid; Torres, Javier; Ferreccio, Catterina; Sampson, Joshua N; Pawlita, Michael; Rabkin, Charles S

    2015-12-15

    Gastric cancer is a rare outcome of chronic Helicobacter pylori infection. Serologic profiles may reveal bacterial, environmental and/or host factors associated with cancer risk. We therefore compared specific anti-H. pylori antibodies among populations with at least twofold differences in gastric cancer mortality from Mexico, Colombia and Chile. Our study included 1,776 adults (mean age 42 years) from three nationally representative surveys, equally divided between residents of high- and low-risk areas. Antibodies to 15 immunogenic H. pylori antigens were measured by fluorescent bead-based multiplex assays; results were summarized to identify overall H. pylori seropositivity. We used logistic regression to model associations between antibody seroreactivity and regional cancer risk (high vs. low), adjusting for country, age and sex. Both risk areas had similar H. pylori seroprevalence. Residents in high- and low-risk areas were seroreactive to a similar number of antigens (means 8.2 vs. 7.9, respectively; adjusted odds ratio, OR: 1.02, p = 0.05). Seroreactivities to Catalase and the known virulence proteins CagA and VacA were each significantly (p < 0.05) associated with residence in high-risk areas, but ORs were moderate (1.26, 1.42 and 1.41, respectively) and their discriminatory power was low (area under the curve < 0.6). The association of Catalase was independent from effects of either CagA or VacA. Sensitivity analyses for antibody associations restricted to H. pylori-seropositive individuals generally replicated significant associations. Our findings suggest that humoral responses to H. pylori are insufficient to distinguish high and low gastric cancer risk in Latin America. Factors determining population variation of gastric cancer burden remain to be identified. PMID:26178251

  6. Molecular Epidemiology of Helicobacter pylori Infection in Nepal: Specific Ancestor Root

    PubMed Central

    Miftahussurur, Muhammad; Sharma, Rabi Prakash; Shrestha, Pradeep Krishna; Suzuki, Rumiko; Uchida, Tomohisa; Yamaoka, Yoshio

    2015-01-01

    Prevalence of Helicobacter pylori infection in Nepal, a low-risk country for gastric cancer, is debatable. To our knowledge, no studies have examined H. pylori virulence factors in Nepal. We determined the prevalence of H. pylori infection by using three different tests, and the genotypes of virulence factors were determined by PCR followed by sequencing. Multilocus sequence typing was used to analyze the population structure of the Nepalese strains. The prevalence of H. pylori infection in dyspeptic patients was 38.4% (56/146), and was significantly related with source of drinking water. In total, 51 strains were isolated and all were cagA-positive. Western-type-cagA (94.1%), cagA pre-EPIYA type with no deletion (92.2%), vacA s1a (74.5%), and m1c (54.9%) were the predominant genotypes. Antral mucosal atrophy levels were significantly higher in patients infected with vacA s1 than in those infected with s2 genotypes (P = 0.03). Several Nepalese strains were H. pylori recombinants with genetic features of South Asian and East Asian genotypes. These included all East-Asian-type-cagA strains, with significantly lesser activity and inflammation in the corpus than the strains of the specific South Asian genotype (P = 0.03 and P = 0.005, respectively). Although the population structure confirmed that most Nepalese strains belonged to the hpAsia2 population, some strains shared hpEurope- and Nepalese-specific components. Nepalese patients infected with strains belonging to hpEurope showed higher inflammation in the antrum than strains from the Nepalese specific population (P = 0.05). These results support that ancestor roots of Kathmandu`s people not only connected with India alone. PMID:26226153

  7. Medicinal plant activity on Helicobacter pylori related diseases

    PubMed Central

    Wang, Yuan-Chuen

    2014-01-01

    More than 50% of the world population is infected with Helicobacter pylori (H. pylori). The bacterium highly links to peptic ulcer diseases and duodenal ulcer, which was classified as a group I carcinogen in 1994 by the WHO. The pathogenesis of H. pylori is contributed by its virulence factors including urease, flagella, vacuolating cytotoxin A (VacA), cytotoxin-associated gene antigen (Cag A), and others. Of those virulence factors, VacA and CagA play the key roles. Infection with H. pylori vacA-positive strains can lead to vacuolation and apoptosis, whereas infection with cagA-positive strains might result in severe gastric inflammation and gastric cancer. Numerous medicinal plants have been reported for their anti-H. pylori activity, and the relevant active compounds including polyphenols, flavonoids, quinones, coumarins, terpenoids, and alkaloids have been studied. The anti-H. pylori action mechanisms, including inhibition of enzymatic (urease, DNA gyrase, dihydrofolate reductase, N-acetyltransferase, and myeloperoxidase) and adhesive activities, high redox potential, and hydrophilic/hydrophobic natures of compounds, have also been discussed in detail. H. pylori-induced gastric inflammation may progress to superficial gastritis, atrophic gastritis, and finally gastric cancer. Many natural products have anti-H. pylori-induced inflammation activity and the relevant mechanisms include suppression of nuclear factor-κB and mitogen-activated protein kinase pathway activation and inhibition of oxidative stress. Anti-H. pylori induced gastric inflammatory effects of plant products, including quercetin, apigenin, carotenoids-rich algae, tea product, garlic extract, apple peel polyphenol, and finger-root extract, have been documented. In conclusion, many medicinal plant products possess anti-H. pylori activity as well as an anti-H. pylori-induced gastric inflammatory effect. Those plant products have showed great potential as pharmaceutical candidates for H. pylori

  8. Microbiota studies in the bile duct strongly suggest a role for Helicobacter pylori in extrahepatic cholangiocarcinoma.

    PubMed

    Avilés-Jiménez, F; Guitron, A; Segura-López, F; Méndez-Tenorio, A; Iwai, S; Hernández-Guerrero, A; Torres, J

    2016-02-01

    Biliary tract cancer or extrahepatic cholangiocarcinoma (ECCA) represents the sixth commonest cause of cancer in the gastrointestinal tract in western countries. We aimed to characterize the microbiota and its predicted associated functions in the biliary tract of ECCA and benign biliary pathology (BBP). Samples were taken from 100 patients with ECCA and 100 patients with BBP by endoscopic cholangio-pancreatography for DNA extraction. Ten patients with ECCA and ten with BBP were selected for microbiota studies using the V4-16S rRNA gene and sequenced in Illumina platform. Microbiota analyses included sample-to-sample distance metrics, ordination/clustering and prediction of functions. Presence of Nesterenkonia sp. and Helicobacter pylori cagA and vacA genes were tested in the 100 ECCA and 100 BBP samples. Phylum Proteobacteria dominated all samples (60.4% average). Ordination multicomponent analyses showed significant microbiota separation between ECCA and BBP (p 0.010). Analyses of 4002 operational taxonomic units with presence variation in at least one category probed a separation of ECCA from BBP. Among these, Nesterenkonia decreased, whereas Methylophilaceae, Fusobacterium, Prevotella, Actinomyces, Novosphingobium and H. pylori increased in ECCA. Predicted associated functions showed increased abundance of H. pylori virulence genes in ECCA. cagA and vacA genes were confirmed by PCR in ECCA and BBP samples. This is the first microbiota report in ECCA and BBP to show significant changes in microbial composition. Bacterial species unusual for human flora were found: Methylophilaceae and Nesterenkonia are reported in hypersaline soils, and Mesorhizobium is a nitrogen-fixing bacterium. Enrichment of virulence genes confirms previous studies suggesting that H. pylori might be associated with ECCA. PMID:26493848

  9. Sequence Divergence and Conservation in Genomes of Helicobacter cetorum Strains from a Dolphin and a Whale

    PubMed Central

    Kersulyte, Dangeruta; Rossi, Mirko; Berg, Douglas E.

    2013-01-01

    Background and Objectives Strains of Helicobacter cetorum have been cultured from several marine mammals and have been found to be closely related in 16 S rDNA sequence to the human gastric pathogen H. pylori, but their genomes were not characterized further. Methods The genomes of H. cetorum strains from a dolphin and a whale were sequenced completely using 454 technology and PCR and capillary sequencing. Results These genomes are 1.8 and 1.95 mb in size, some 7–26% larger than H. pylori genomes, and differ markedly from one another in gene content, and sequences and arrangements of shared genes. However, each strain is more related overall to H. pylori and its descendant H. acinonychis than to other known species. These H. cetorum strains lack cag pathogenicity islands, but contain novel alleles of the virulence-associated vacuolating cytotoxin (vacA) gene. Of particular note are (i) an extra triplet of vacA genes with ≤50% protein-level identity to each other in the 5′ two-thirds of the gene needed for host factor interaction; (ii) divergent sets of outer membrane protein genes; (iii) several metabolic genes distinct from those of H. pylori; (iv) genes for an iron-cofactored urease related to those of Helicobacter species from terrestrial carnivores, in addition to genes for a nickel co-factored urease; and (v) members of the slr multigene family, some of which modulate host responses to infection and improve Helicobacter growth with mammalian cells. Conclusions Our genome sequence data provide a glimpse into the novelty and great genetic diversity of marine helicobacters. These data should aid further analyses of microbial genome diversity and evolution and infection and disease mechanisms in vast and often fragile ocean ecosystems. PMID:24358262

  10. Analysis of Clinical Isolates of Helicobacter pylori in Pakistan Reveals High Degrees of Pathogenicity and High Frequencies of Antibiotic Resistance

    PubMed Central

    Rasheed, Faisal; Campbell, Barry James; Alfizah, Hanafiah; Varro, Andrea; Zahra, Rabaab; Yamaoka, Yoshio; Pritchard, David Mark

    2014-01-01

    Background Antibiotic resistance in Helicobacter pylori contributes to failure in eradicating the infection and is most often due to point and missense mutations in a few key genes. Methods The antibiotic susceptibility profiles of H. pylori isolates from 46 Pakistani patients were determined by Etest. Resistance and pathogenicity genes were amplified, and sequences were analyzed to determine the presence of mutations. Results A high percentage of isolates (73.9%) were resistant to metronidazole (MTZ), with considerable resistance to clarithromycin (CLR; 47.8%) and amoxicillin (AML; 54.3%) also observed. Relatively few isolates were resistant to tetracycline (TET; 4.3%) or to ciprofloxacin (CIP; 13%). However, most isolates (n = 43) exhibited resistance to one or more antibiotics. MTZ-resistant isolates contained missense mutations in oxygen-independent NADPH nitroreductase (RdxA; 8 mutations found) and NADH flavin oxidoreductase (FrxA; 4 mutations found). In the 23S rRNA gene, responsible for CLR resistance, a new point mutation (A2181G) and 4 previously reported mutations were identified. Pathogenicity genes cagA, dupA, and vacA s1a/m1 were detected frequently in isolates which were also found to be resistant to MTZ, CLR, and AML. A high percentage of CagA and VacA seropositivity was also observed in these patients. Phylogenetic analysis of partial sequences showed uniform distribution of the 3′ region of cagA throughout the tree. Conclusions We have identified H. pylori isolates in Pakistan which harbor pathogenicity genes and worrying antibiotic resistance profiles as a result of having acquired multiple point and missense mutations. H. pylori eradication regimens should therefore be reevaluated in this setting. PMID:24827414

  11. Molecular Epidemiology of Helicobacter pylori Infection in Nepal: Specific Ancestor Root.

    PubMed

    Miftahussurur, Muhammad; Sharma, Rabi Prakash; Shrestha, Pradeep Krishna; Suzuki, Rumiko; Uchida, Tomohisa; Yamaoka, Yoshio

    2015-01-01

    Prevalence of Helicobacter pylori infection in Nepal, a low-risk country for gastric cancer, is debatable. To our knowledge, no studies have examined H. pylori virulence factors in Nepal. We determined the prevalence of H. pylori infection by using three different tests, and the genotypes of virulence factors were determined by PCR followed by sequencing. Multilocus sequence typing was used to analyze the population structure of the Nepalese strains. The prevalence of H. pylori infection in dyspeptic patients was 38.4% (56/146), and was significantly related with source of drinking water. In total, 51 strains were isolated and all were cagA-positive. Western-type-cagA (94.1%), cagA pre-EPIYA type with no deletion (92.2%), vacA s1a (74.5%), and m1c (54.9%) were the predominant genotypes. Antral mucosal atrophy levels were significantly higher in patients infected with vacA s1 than in those infected with s2 genotypes (P = 0.03). Several Nepalese strains were H. pylori recombinants with genetic features of South Asian and East Asian genotypes. These included all East-Asian-type-cagA strains, with significantly lesser activity and inflammation in the corpus than the strains of the specific South Asian genotype (P = 0.03 and P = 0.005, respectively). Although the population structure confirmed that most Nepalese strains belonged to the hpAsia2 population, some strains shared hpEurope- and Nepalese-specific components. Nepalese patients infected with strains belonging to hpEurope showed higher inflammation in the antrum than strains from the Nepalese specific population (P = 0.05). These results support that ancestor roots of Kathmandu`s people not only connected with India alone. PMID:26226153

  12. Virulence of infecting Helicobacter pyloristrains and intensity of mononuclear cell infiltration are associated with levels of DNA hypermethylation in gastric mucosae

    PubMed Central

    Schneider, Barbara G; Piazuelo, M Blanca; Sicinschi, Liviu A; Mera, Robertino; Peng, Dun-Fa; Roa, Juan Carlos; Romero-Gallo, Judith; Delgado, Alberto G; de Sablet, Thibaut; Bravo, Luis E; Wilson, Keith T; El-Rifai, Wael; Peek Jr, Richard M; Correa, Pelayo

    2013-01-01

    DNA methylation changes are known to occur in gastric cancers and in premalignant lesions of the gastric mucosae. In order to examine variables associated with methylation levels, we quantitatively evaluated DNA methylation in tumors, non-tumor gastric mucosae, and in gastric biopsies at promoters of 5 genes with methylation alterations that discriminate gastric cancers from non-tumor epithelia (EN1, PCDH10, RSPO2, ZIC1, and ZNF610). Among Colombian subjects at high and low risk for gastric cancer, biopsies from subjects from the high-risk region had significantly higher levels of methylation at these 5 genes than samples from subjects in the low risk region (p ≤ 0.003). When results were stratified by Helicobacter pylori infection status, infection with a cagA positive, vacA s1m1 strain was significantly associated with highest methylation levels, compared with other strains (p = 0.024 to 0.001). More severe gastric inflammation and more advanced precancerous lesions were also associated with higher levels of DNA methylation (p ≤ 0.001). In a multivariate model, location of residence of the subject and the presence of cagA and vacA s1m1 in the H. pylori strain were independent variables associated with higher methylation in all 5 genes. High levels of mononuclear cell infiltration were significantly related to methylation in PCDH10, RSPO2, and ZIC1 genes. These results indicate that for these genes, levels of methylation in precancerous lesions are related to H. pylori virulence, geographic region and measures of chronic inflammation. These genes seem predisposed to sustain significant quantitative changes in DNA methylation at early stages of the gastric precancerous process. PMID:24128875

  13. Detection of Helicobacter pylori in oropharyngeal lymphatic tissue with real-time PCR and assessment of its carcinogenic potential.

    PubMed

    Lukeš, Petr; Pavlík, Emil; Potuznikova, Bela; Nartova, Eva; Foltynova, Eva; Plzak, Jan; Katra, Rami; Sterzl, Ivan; Bartunkova, Jirina; Betka, Jan; Astl, Jaromir

    2014-02-01

    Helicobacter pylori (HP) is considered a major gastric pathogen with oncogenic potential. The aim of this study was to determine whether HP is present in oropharyngeal lymphoid tissue and whether oropharyngeal HP strains carry virulence factor genes known to be involved in gastric carcinogenesis. The study included 104 subjects (41 patients with tonsillar carcinoma, 38 with chronic tonsillitis and 25 with obstructive sleep apnoea syndrome--OSAS). Detection of specific serum anti-HP antibodies was performed with an ELISA. The presence of HP in tissue was determined by culture and real-time PCR. Detection of virulence factors genes was also performed. Specific antibodies were found in 78.05% of tumour cases, 34.21% of chronic tonsillitis cases, and 72.0% of OSAS cases. The presence of HP in the tissue was detected in 73.91% of tonsillar tumours, 70.0% of tonsillitis cases, and 69.23% of OSAS specimens. The results of the virulence factor gene analysis showed the majority of the s1b (52.4%) and m2 (59.5%) alleles of vacA gene and limited abundance of cagA gene (12.5%). Results confirm that HP may colonise oropharyngeal lymphoid tissue. Oropharyngeal HP colonisation was frequently found in the oropharyngeal cancer group and in patients with benign oropharyngeal diseases. A virulence factor gene analysis showed differences from the predominant strains most commonly found in the stomach. The strains obtained from the oropharynx differed primarily by the lower abundance of the cagA gene and carried the less virulent vacA gene allele combination. PMID:23744180

  14. Dinámica global en galaxias elípticas

    NASA Astrophysics Data System (ADS)

    Pérez, M. J.; Cincotta, P. M.; Giordano, C. M.

    Con el propósito de determinar propiedades dinámicas globales en sistemas triaxiales no integrables, utilizamos una nueva herramienta conocida como ``Mean Exponential Growth factor of Nearby Orbits'' (MEGNO), introducida por Cincotta y Simó (2000). Esta técnica no sólo resulta eficiente para investigar ambas componentes del espacio fase, regular y caótica, sino que también, provee una medida de la hiperbolicidad en el dominio caótico que coincide con la dada por el Lyapunov Characteristic Number (LCN). Previamente este método ha sido aplicado al estudio de modelos simples, y últimamente en el campo de la Mecánica Celeste, al estudio de sistemas planetarios extrasolares. En esta presentación, ilustraremos algunas de las propiedades más importantes del MEGNO, aplic& acute;andolo al potencial tridimensional de Stäckel perturbado.

  15. Astronomía Mocoví

    NASA Astrophysics Data System (ADS)

    López, A.; Giménez Benitez, S.; Fernández, L.

    El presente trabajo, es una revisión crítica de la astronomía en la cultura Mocoví, aportando a lo realizado previamente por Lehmann Nistche (Lehmann Nistche, 1924 y 1927) el resultado de nuestro trabajo de campo. Un mayor conocimiento de las cosmovisiones de las etnias de esta área es fundamental para una mejor comprensión de la dispersión de las ideas cosmológicas entre los pueblos aborígenes americanos, dada la importancia del corredor chaqueño como conexión entre las altas culturas andinas, la mesopotamia y la región pampeana (Susnik, 1972). Para ello se realiza una comparación con otras cosmovisiones del área americana. Nuestro aporte se enmarca dentro de las actuales líneas de trabajo mundialmente en desarrollo en Astronomía en la Cultura.

  16. Produccion Gaseosa del Cometa Halley: Erupciones Y Fotodisociacion del Radical OH

    NASA Astrophysics Data System (ADS)

    Silva, A. M.; Mirabel, I. F.

    1990-11-01

    RESUMEN:En este trabajo informamos la detecci6n de 20 erupciones en la li'nea de =18cm (1667MHz) del radical OH en el Cometa Halley.Las observaciones incluyen todos los monitoreos existentes y se extienden desde 120 dias antes del perihelio hasta 90 dias despues.Se detectan bruscos crecimientos en el flujo medido,hasta un factor 1O,seguidos por decaimientos lentos asociados con la fotodisociaci6n del OH. Se obtuvieron valores para el tiempo de vida fotoquimico del OH y del H2O basandose en el modelo desarrollado previamente por Silva(1988). Esos tiempos de vida estan de acuerdo con predicciones teoricas y con las observaciones en el Ultravioleta, y los resultados, los que son fuertemente dependientes de la velocidad heliocentrica del Coineta (variando hasta un factor 6), han sido calculados para varios rangos de velocidad entre +28 y -28 km/seg. Key wo'L :

  17. Screening Helicobacter pylori genes induced during infection of mouse stomachs

    PubMed Central

    Singh, Aparna; Hodgson, Nathaniel; Yan, Ming; Joo, Jungsoo; Gu, Lei; Sang, Hong; Gregory-Bryson, Emmalena; Wood, William G; Ni, Yisheng; Smith, Kimberly; Jackson, Sharon H; Coleman, William G

    2012-01-01

    AIM: To investigate the effect of in vivo environment on gene expression in Helicobacter pylori (H. pylori) as it relates to its survival in the host. METHODS: In vivo expression technology (IVET) systems are used to identify microbial virulence genes. We modified the IVET-transcriptional fusion vector, pIVET8, which uses antibiotic resistance as the basis for selection of candidate genes in host tissues to develop two unique IVET-promoter-screening vectors, pIVET11 and pIVET12. Our novel IVET systems were developed by the fusion of random Sau3A DNA fragments of H. pylori and a tandem-reporter system of chloramphenicol acetyltransferase and beta-galactosidase. Additionally, each vector contains a kanamycin resistance gene. We used a mouse macrophage cell line, RAW 264.7 and mice, as selective media to identify specific genes that H. pylori expresses in vivo. Gene expression studies were conducted by infecting RAW 264.7 cells with H. pylori. This was followed by real time polymerase chain reaction (PCR) analysis to determine the relative expression levels of in vivo induced genes. RESULTS: In this study, we have identified 31 in vivo induced (ivi) genes in the initial screens. These 31 genes belong to several functional gene families, including several well-known virulence factors that are expressed by the bacterium in infected mouse stomachs. Virulence factors, vacA and cagA, were found in this screen and are known to play important roles in H. pylori infection, colonization and pathogenesis. Their detection validates the efficacy of these screening systems. Some of the identified ivi genes have already been implicated to play an important role in the pathogenesis of H. pylori and other bacterial pathogens such as Escherichia coli and Vibrio cholerae. Transcription profiles of all ivi genes were confirmed by real time PCR analysis of H. pylori RNA isolated from H. pylori infected RAW 264.7 macrophages. We compared the expression profile of H. pylori and RAW 264

  18. Radial patterns of bitumen dykes around Quaternary volcanoes, provinces of northern Neuquén and southernmost Mendoza, Argentina

    NASA Astrophysics Data System (ADS)

    Cobbold, Peter R.; Ruffet, Gilles; Leith, Leslie; Loseth, Helge; Rodrigues, Nuno; Leanza, Hector A.; Zanella, Alain

    2014-12-01

    Where the Neuquén Basin of Argentina abuts the Andes, hundreds of veins of solid hydrocarbon (bitumen) are visible at the surface. Many of these veins became mines, especially in the last century. By consensus, the bitumen has resulted from maturation of organic-rich shales, especially the Vaca Muerta Fm of Late Jurassic age, but also the Agrio Fm of Early Cretaceous age. To account for their maturation, recent authors have invoked regional subsidence, whereas early geologists invoked magmatic activity. During 12 field seasons (since 1998), we have tracked down the bitumen localities, mapped the veins and host rocks, sampled them, studied their compositions, and dated some of them. In the provinces of northern Neuquén and southernmost Mendoza, the bitumen veins are mostly sub-vertical dykes. They tend to be straight and continuous, crosscutting regional structures and strata of all ages, from Jurassic to Palaeocene. Most of the localities lie within 70 km of Tromen volcano, although four are along the Rio Colorado fault zone and another two are at the base of Auca Mahuida volcano. On both volcanic edifices, lavas are of late Pliocene to Pleistocene age. Although regionally many of the bitumen dykes tend to track the current direction of maximum horizontal tectonic stress (ENE), others do not. However, most of the dykes radiate outward from the volcanoes, especially Tromen. Thicknesses of dykes tend to be greatest close to Tromen and where the host rocks are the most resistant to fracturing. Many of the dykes occur in the exhumed hanging walls of deep thrusts, especially at the foot of Tromen. Here the bitumen is in places of high grade (impsonite), whereas further out it tends to be of medium grade (grahamite). A few bitumen dykes contain fragments of Vaca Muerta shale, so that we infer forceful expulsion of source rock. At Curacó Mine, some shale fragments contain bedding-parallel veins of fibrous calcite (beef) and these contain some bitumen, which is

  19. Evolution in an oncogenic bacterial species with extreme genome plasticity: Helicobacter pylori East Asian genomes

    PubMed Central

    2011-01-01

    Background The genome of Helicobacter pylori, an oncogenic bacterium in the human stomach, rapidly evolves and shows wide geographical divergence. The high incidence of stomach cancer in East Asia might be related to bacterial genotype. We used newly developed comparative methods to follow the evolution of East Asian H. pylori genomes using 20 complete genome sequences from Japanese, Korean, Amerind, European, and West African strains. Results A phylogenetic tree of concatenated well-defined core genes supported divergence of the East Asian lineage (hspEAsia; Japanese and Korean) from the European lineage ancestor, and then from the Amerind lineage ancestor. Phylogenetic profiling revealed a large difference in the repertoire of outer membrane proteins (including oipA, hopMN, babABC, sabAB and vacA-2) through gene loss, gain, and mutation. All known functions associated with molybdenum, a rare element essential to nearly all organisms that catalyzes two-electron-transfer oxidation-reduction reactions, appeared to be inactivated. Two pathways linking acetyl~CoA and acetate appeared intact in some Japanese strains. Phylogenetic analysis revealed greater divergence between the East Asian (hspEAsia) and the European (hpEurope) genomes in proteins in host interaction, specifically virulence factors (tipα), outer membrane proteins, and lipopolysaccharide synthesis (human Lewis antigen mimicry) enzymes. Divergence was also seen in proteins in electron transfer and translation fidelity (miaA, tilS), a DNA recombinase/exonuclease that recognizes genome identity (addA), and DNA/RNA hybrid nucleases (rnhAB). Positively selected amino acid changes between hspEAsia and hpEurope were mapped to products of cagA, vacA, homC (outer membrane protein), sotB (sugar transport), and a translation fidelity factor (miaA). Large divergence was seen in genes related to antibiotics: frxA (metronidazole resistance), def (peptide deformylase, drug target), and ftsA (actin-like, drug target

  20. Taking Geoscience to Public Schools: Attitude and Knowledge Relationships

    NASA Astrophysics Data System (ADS)

    Silliman, J. E.; Hansen, A.; McDonald, J.; Martinez, M.

    2005-12-01

    The Cabeza de Vaca Earthmobile Program is an ongoing project that is designed to strengthen geoscience education in South Texas public schools. It began in June 2003 and is funded by the National Science Foundation. This outreach program involves collaboration between Texas A&M University-Corpus Christi and four independent school districts in South Texas with support from the South Texas Rural Systemic Initiative, another NSF-funded project. Additional curriculum support has been provided by various local and state organizations. Across Texas, fifth grade students are demonstrating a weakness in geoscience concepts as evidenced by their scores on the Texas Assessment of Knowledge and Skills. As a result, fifth and sixth grade public school students from low-income school districts were selected to participate in this program. At this age students are already making decisions that will affect their high school and college years. The main purpose of this project is to encourage these students, many of whom are Hispanic, to become geoscientists. This purpose is accomplished by enhancing their geoscience knowledge, nurturing their interest in geoscience and showing them what careers are available in the geosciences. Educators and scientists collaborate to engage students in scientific discovery through hands-on laboratory exercises and exposure to state-of-the-art technology (laptop computers, weather stations, telescopes, etc.). Students' family members become involved in the geoscience learning process as they participate in Family Science Night activities. Family Science Nights constitute an effective venue to reach the public. During the course of the Cabeza de Vaca Earthmobile Program, investigators have measured success in two ways: improvement in students' knowledge of geoscience concepts and change in students' attitudes towards geoscience. Findings include significant improvement in students' knowledge of geoscience. Students also report more positive

  1. Growth Phase-Dependent Response of Helicobacter pylori to Iron Starvation

    PubMed Central

    Merrell, D. Scott; Thompson, Lucinda J.; Kim, Charles C.; Mitchell, Hazel; Tompkins, Lucy S.; Lee, Adrian; Falkow, Stanley

    2003-01-01

    Iron is an essential nutrient that is often found in extremely limited available quantities within eukaryotic hosts. Because of this, many pathogenic bacteria have developed regulated networks of genes important for iron uptake and storage. In addition, it has been shown that many bacteria use available iron concentrations as a signal to regulate virulence gene expression. We have utilized DNA microarray technology to identify genes of the human pathogen Helicobacter pylori that are differentially regulated on a growth-inhibiting shift to iron starvation conditions. In addition, the growth phase-dependent expression of these genes was investigated by examining both exponential and stationary growth phase cultures. We identified known iron-regulated genes, as well as a number of genes whose regulation by iron concentration was not previously appreciated. Included in the list of regulated factors were the known virulence genes cagA, vacA, and napA. We examined the effect of iron starvation on the motility of H. pylori and found that exponential- and stationary-phase cultures responded differently to the stress. We further found that while growing cells are rapidly killed by iron starvation, stationary-phase cells show a remarkable ability to survive iron depletion. Finally, bioinformatic analysis of the predicted promoter regions of the differentially regulated genes led to identification of several putative Fur boxes, suggesting a direct role for Fur in iron-dependent regulation of these genes. PMID:14573673

  2. “Non-Toxic” Proteins of the Botulinum Toxin Complex Exert In-vivo Toxicity

    PubMed Central

    Miyashita, Shin-Ichiro; Sagane, Yoshimasa; Suzuki, Tomonori; Matsumoto, Takashi; Niwa, Koichi; Watanabe, Toshihiro

    2016-01-01

    The botulinum neurotoxin (BoNT) causes muscle paralysis and is the most potent toxin in nature. BoNT is associated with a complex of auxiliary “Non-Toxic” proteins, which constitute a large-sized toxin complex (L-TC). However, here we report that the “Non-Toxic” complex of serotype D botulinum L-TC, when administered to rats, exerts in-vivo toxicity on small-intestinal villi. Moreover, Serotype C and D of the “Non-Toxic” complex, but not BoNT, induced vacuole-formation in a rat intestinal epithelial cell line (IEC-6), resulting in cell death. Our results suggest that the vacuole was formed in a manner distinct from the mechanism by which Helicobacter pylori vacuolating toxin (VacA) and Vibrio cholerae haemolysin induce vacuolation. We therefore hypothesise that the serotype C and D botulinum toxin complex is a functional hybrid of the neurotoxin and vacuolating toxin (VT) which arose from horizontal gene transfer from an ancestral BoNT-producing bacterium to a hypothetical VT-producing bacterium. PMID:27507612

  3. A review of WIPP (Waste Isolation Pilot Plant) repository clays and their relationship to clays of adjacent strata

    SciTech Connect

    Krumhansl, J.L.; Kimball, K.M.; Stein, C.L.

    1990-12-01

    The Salado Formation is a thick evaporite sequence located in the Permian Delaware Basin of southeastern New Mexico. This study focuses on the intense diagenetic alteration that has affected the small amounts of clay, feldspar, and quartz washed into the basin during salt deposition. These changes are of more than academic interest since this formation also houses the WIPP (Waste Isolation Pilot Plant). Site characterization concerns warrant compiling a detailed data base describing the clays in and around the facility horizon. An extensive sampling effort was undertaken to address these programmatic issues as well as to provide additional insight regarding diagenetic mechanisms in the Salado. Seventy-five samples were collected from argillaceous partings in halite at the stratigraphic level of the Waste Isolation Pilot Plant (WIPP). These were compared with twenty-eight samples from cores of the Vaca Triste member of the Salado, a thin clastic unit at the top of the McNutt potash zone, and with a clay-rich sample from the lower contact of the Culebra Dolomite (in the overlying Rustler Formation). These settings were compared to assess the influence of differences in brine chemistry (i.e., halite and potash facies, normal to hypersaline marine conditions) and sediment composition (clays, sandy silt, dolomitized limestone) on diagenetic processes. 44 refs., 11 figs., 5 tabs.

  4. Helicobacter pylori and gastric cancer in the Middle East: A new enigma?

    PubMed Central

    Hussein, Nawfal R

    2010-01-01

    The Middle East is the home of ethnic groups from three main backgrounds: Semitic (Arabs and Jews), Indo-European (Persians and Kurdish) and Turkic (Turkish and Turkmens). Its geographic location, which has been under continuous influences from Asia, Europe and Africa, has made it an ideal site for epidemiological studies on Helicobacter pylori (H. pylori) infection and genotyping. The gastric cancer rate differs in this region from very high in Iran (26.1/105) to low in Israel (12.5/105) and very low in Egypt (3.4/105). Epidemiological studies showed that the prevalence of H. pylori is almost similar in those countries with a high level of infection in childhood. Importantly, the frequency of vacA s1 and m1 regions and cagA+ genotypes were higher in non Semitic populations who inhabit the North than Semitic populations, the inhabitants of Southern parts of the Middle East. H. pylori infection prevalence, distribution pattern of virulence factors, diet and smoking could not have explained the difference in cancer rate. This reflects the multifactorial aetiology of gastric cancer and suggests that H. pylori infection does not always directly correlate with the risk for gastrointestinal disease, such as gastric cancer. Further detailed investigations and international comparative studies of each risk factor need to be performed to investigate whether this represents a true enigma. PMID:20614477

  5. Down-regulated Th17 Responses Are Associated with Reduced Gastritis in Helicobacter pylori-infected Children

    PubMed Central

    Bimczok, Diane; Shaffer, Carrie L.; Cover, Timothy L.; Venegas, Alejandro; Salazar, Maria G.; Smythies, Lesley E.; Harris, Paul R.; Smith, Phillip D.

    2013-01-01

    Helicobacter pylori induces less gastric inflammation in children than adults. Here we investigated whether this reduced inflammation involves dysregulated Th17 responses. H. pylori-infected children and adults in Santiago, Chile had similar levels of H. pylori colonization, proportions of bacteria containing cagA and s1/s2 vacA markers of virulence and strain genotypes (predominantly hpEurope), but the children had significantly reduced levels of gastric inflammation and neutrophil infiltration. The reduced neutrophil accumulation in infected children was accompanied by significantly fewer gastric Th17 cells and significantly lower levels of IL-17-specific mRNA and protein compared to infected adults. The gastric mucosa of H. pylori-infected children also contained higher numbers of IL-10+ cells and increased levels of both IL-10 and Foxp3 mRNA compared to that of infected adults. Thus, reduced gastric inflammation, including diminished neutrophil accumulation, in H. pylori-infected children compared with infected adults is likely due to down-regulated gastric Th17/IL-17 responses as a consequence of enhanced mucosal regulatory T cell activity in the children. PMID:23299619

  6. Dual roles of plasmalemmal chloride channels in induction of cell death.

    PubMed

    Okada, Yasunobu; Maeno, Emi; Shimizu, Takahiro; Manabe, Kenichi; Mori, Shin-Ichiro; Nabekura, Takashi

    2004-06-01

    Even under anisotonic conditions, most cells can regulate their volume by mechanisms called regulatory volume decrease (RVD) and increase (RVI) after osmotic swelling or shrinkage, respectively. In contrast, the initial processes of necrosis and apoptosis are associated with persistent swelling and shrinkage. Necrotic volume increase (NVI) is initiated by uptake of osmolytes, such as Na+, Cl- and lactate, under conditions of injury, hypoxia, ischaemia, acidosis or lactacidosis. Persistence of NVI is caused by dysfunction of RVD due to impairment of volume-sensitive Cl- channels under conditions of ATP deficiency or lactacidosis. Both lactacidosis-induced RVD dysfunction and necrotic cell death are prevented by pretreatment of cells with the vacuolating cytotoxin-A (VacA) toxin protein purified from Helicobacter pylori, which forms a lactacidosis-resistant anion channel. Apoptotic volume decrease (AVD) is triggered by activation of K+ and Cl- conductances following stimulation with a mitochondrion-mediated or death receptor-mediated apoptosis inducer. Apoptotic cell death can be prevented by blocking the Cl- channels but not the K+-Cl- cotransporters. Thus, the volume regulatory anion channel plays, unless impaired, a cell-rescuing role in the necrotic process by ensuring RVD after swelling induced by necrotic insults, whereas normotonic activation of the anion channel plays a cell-killing role in the apoptotic process by triggering AVD following stimulation with apoptosis inducers. PMID:15103464

  7. Efficacy of the antimicrobial peptide TP4 against Helicobacter pylori infection: in vitro membrane perturbation via micellization and in vivo suppression of host immune responses in a mouse model

    PubMed Central

    Narayana, Jayaram Lakshmaiah; Huang, Han-Ning; Wu, Chang-Jer; Chen, Jyh-Yih

    2015-01-01

    Helicobacter pylori infection is marked by a strong association with various gastric diseases, including gastritis, ulcers, and gastric cancer. Antibiotic treatment regimens have low success rates due to the rapid occurrence of resistant H. pylori strains, necessitating the development of novel anti-H. pylori strategies. Here, we investigated the therapeutic potential of a novel peptide, Tilapia Piscidin 4 (TP4), against multidrug resistant gastric pathogen H. pylori, based on its in vitro and in vivo efficacy. TP4 inhibited the growth of both antibiotic-sensitive and -resistant H. pylori (CagA+, VacA+) via membrane micelle formation, which led to membrane depolarization and extravasation of cellular constituents. During colonization of gastric tissue, H. pylori infection maintains high T regulatorysubsets and a low Th17/Treg ratio, and results in expression of both pro- and anti-inflammatory cytokines. Treatment with TP4 suppressed Treg subset populations and pro- and anti-inflammatory cytokines. TP4 restored the Th17/Treg balance, which resulted in early clearance of H. pylori density and recovery of gastric morphology. Toxicity studies demonstrated that TP4 treatment has no adverse effects in mice or rabbits. The results of this study indicate that TP4 may be an effective and safe monotherapeutic agent for the treatment of multidrug resistant H. pylori infections. PMID:26002554

  8. Growth phase-dependent composition of the Helicobacter pylori exoproteome.

    PubMed

    Snider, Christina A; Voss, Bradley J; McDonald, W Hayes; Cover, Timothy L

    2016-01-01

    Helicobacter pylori colonizes the human stomach and is associated with an increased risk of gastric cancer and peptic ulcer disease. Analysis of H. pylori protein secretion is complicated by the occurrence of bacterial autolysis. In this study, we analyzed the exoproteome of H. pylori at multiple phases of bacterial growth and identified 74 proteins that are selectively released into the extracellular space. These include proteins known to cause alterations in host cells, antigenic proteins, and additional proteins that have not yet been studied in any detail. The composition of the H. pylori exoproteome is dependent on the phase of bacterial growth. For example, the proportional abundance of the vacuolating toxin VacA in culture supernatant is higher during late growth phases than early growth phases, whereas the proportional abundance of many other proteins is higher during early growth phases. We detected marked variation in the subcellular localization of putative secreted proteins within soluble and membrane fractions derived from intact bacteria. By providing a comprehensive view of the H. pylori exoproteome, these results provide new insights into the array of secreted H. pylori proteins that may cause alterations in the gastric environment. PMID:26363098

  9. Identification of putative vaccine candidates against Helicobacter pylori exploiting exoproteome and secretome: a reverse vaccinology based approach.

    PubMed

    Naz, Anam; Awan, Faryal Mehwish; Obaid, Ayesha; Muhammad, Syed Aun; Paracha, Rehan Zafar; Ahmad, Jamil; Ali, Amjad

    2015-06-01

    Helicobacter pylori (H. pylori) is an important pathogen associated with diverse gastric disorders ranging from peptic ulcer to malignancy. It has also been recognized by the World Health Organization (WHO) as class I carcinogen. Conventional treatment regimens for H. pylori seem to be ineffective, possibly due to antibiotic resistance mechanisms acquired by the pathogen. In this study we have successfully employed a reverse vaccinology approach to predict the potential vaccine candidates against H. pylori. The predicted potential vaccine candidates include vacA, babA, sabA, fecA and omp16. Host-pathogen interactions analysis elaborated their direct or indirect role in the specific signaling pathways including epithelial cell polarity, metabolism, secretion system and transport. Furthermore, surface-exposed antigenic epitopes were predicted and analyzed for conservation among 39 complete genomes of H. pylori (Genbank) for all the candidate proteins. These epitopes may serve as a base for the development of broad spectrum peptide or multi-component vaccines against H. pylori. We also believe that the proposed pipeline can be extended to other pathogens and for the identification of novel candidates for the development of effective vaccines. PMID:25818402

  10. Pathogenesis of Helicobacter pylori infection.

    PubMed

    Backert, Steffen; Neddermann, Matthias; Maubach, Gunter; Naumann, Michael

    2016-09-01

    Helicobacter pylori is estimated to infect more than half of the worlds human population and represents a major risk factor for chronic gastritis, peptic ulcer disease, MALT lymphoma, and gastric adenocarcinoma. H. pylori infection and clinical consequences are controlled by highly complex interactions between the host, colonizing bacteria, and environmental parameters. Important bacterial determinants linked with gastric disease development include the cag pathogenicity island encoding a type IV secretion system (T4SS), the translocated effector protein CagA, vacuolating cytotoxin VacA, adhesin BabA, urease, serine protease HtrA, secreted outer membrane vesicles, and many others. The high quantity of these factors and allelic changes in the corresponding genes reveals a sophisticated picture and problems in evaluating the impact of each distinct component. Extensive work has been performed to pinpoint molecular processes related to H. pylori-triggered pathogenesis using Mongolian gerbils, mice, primary tissues, as well as novel in vitro model systems such as gastroids. The manipulation of host signaling cascades by the bacterium appears to be crucial for inducing pathogenic downstream activities and gastric disease progression. Here, we review the most recent advances in this important research area. PMID:27531534

  11. High CO/sub 2/, high H/sub 2/S removal with selexol solvent

    SciTech Connect

    Sweny, J.W.

    1980-01-01

    The Selexol Solvent process of Allied Chemical Corp. for treating both sour natural gases and coal- or oil-derived synthesis gases, uses strong solubility differences of various gaseous components in Selexol that acts as physical solvent. This permits a variety of uses in any gas purification service, including bulk removal of CO/sub 2/ alone or combined with water dew point control and recovery of C/sub 5/+ paraffins, as in the Lo-Vaca Gathering Co.'s Grey Ranch gas plant; removal of small amounts of H/sub 2/S (< 1 g/100 cu ft) together with CO/sub 2/, or for higher concentrations, by using a split cycle scheme with H/sub 2/S stripping, as in Northern Natural Gas Co.'s Oates, Tex., plant; the two-stage H/sub 2/S-CO/sub 2/ absorption required in SNG or synthesis gas generation from coal to minimize air pollution by H/sub 2/S, as in Bituminous Coal Research Inc.'s Bi-Gas pilot plant; and bulk removal of H/sub 2/S together with CO/sub 2/, mercaptans, and carbonyl sulfide in a single absorber, as in Norddeutsche Erdgasaufbereitungsges. m.b.H.'s NEAG II plant.

  12. Effective treatment of allergic airway inflammation with Helicobacter pylori immunomodulators requires BATF3-dependent dendritic cells and IL-10.

    PubMed

    Engler, Daniela B; Reuter, Sebastian; van Wijck, Yolanda; Urban, Sabine; Kyburz, Andreas; Maxeiner, Joachim; Martin, Helen; Yogev, Nir; Waisman, Ari; Gerhard, Markus; Cover, Timothy L; Taube, Christian; Müller, Anne

    2014-08-12

    The prevalence of allergic asthma and other atopic diseases has reached epidemic proportions in large parts of the developed world. The gradual loss of the human indigenous microbiota has been held responsible for this trend. The bacterial pathogen Helicobacter pylori is a constituent of the normal gastric microbiota whose presence has been inversely linked to allergy and asthma in humans and experimental models. Here we show that oral or i.p. tolerization with H. pylori extract prevents the airway hyperresponsiveness, bronchoalveolar eosinophilia, pulmonary inflammation, and Th2 cytokine production that are hallmarks of allergen-induced asthma in mice. Asthma protection is not conferred by extracts from other enteropathogens and requires a heat-sensitive H. pylori component and the DC-intrinsic production of IL-10. The basic leucine zipper ATF-like 3 (BATF3)-dependent CD103(+)CD11b(-) dendritic cell lineage is enriched in the lungs of protected mice and strictly required for protection. Two H. pylori persistence determinants, the γ-glutamyl-transpeptidase GGT and the vacuolating cytotoxin VacA, are required and sufficient for asthma protection and can be administered in purified form to prevent asthma. In conclusion, we provide preclinical evidence for the concept that the immunomodulatory properties of H. pylori can be exploited for tolerization strategies aiming to prevent allergen-induced asthma. PMID:25074917

  13. Comparative genomic analysis of Helicobacter pylori from Malaysia identifies three distinct lineages suggestive of differential evolution

    PubMed Central

    Kumar, Narender; Mariappan, Vanitha; Baddam, Ramani; Lankapalli, Aditya K.; Shaik, Sabiha; Goh, Khean-Lee; Loke, Mun Fai; Perkins, Tim; Benghezal, Mohammed; Hasnain, Seyed E.; Vadivelu, Jamuna; Marshall, Barry J.; Ahmed, Niyaz

    2015-01-01

    The discordant prevalence of Helicobacter pylori and its related diseases, for a long time, fostered certain enigmatic situations observed in the countries of the southern world. Variation in H. pylori infection rates and disease outcomes among different populations in multi-ethnic Malaysia provides a unique opportunity to understand dynamics of host–pathogen interaction and genome evolution. In this study, we extensively analyzed and compared genomes of 27 Malaysian H. pylori isolates and identified three major phylogeographic lineages: hspEastAsia, hpEurope and hpSouthIndia. The analysis of the virulence genes within the core genome, however, revealed a comparable pathogenic potential of the strains. In addition, we identified four genes limited to strains of East-Asian lineage. Our analyses identified a few strain-specific genes encoding restriction modification systems and outlined 311 core genes possibly under differential evolutionary constraints, among the strains representing different ethnic groups. The cagA and vacA genes also showed variations in accordance with the host genetic background of the strains. Moreover, restriction modification genes were found to be significantly enriched in East-Asian strains. An understanding of these variations in the genome content would provide significant insights into various adaptive and host modulation strategies harnessed by H. pylori to effectively persist in a host-specific manner. PMID:25452339

  14. Three unsuccessful treatments of Helicobacter pylori infection by a highly virulent strain with quadruple antibiotic resistance.

    PubMed

    Boyanova, Lyudmila; Evstatiev, Ivailo; Yordanov, Daniel; Markovska, Rumyana; Mitov, Ivan

    2016-07-01

    We report a case of an adult patient undergoing three unsuccessful Helicobacter pylori treatments, including proton pump inhibitor (PPI), bismuth subcitrate, metronidazole and tetracycline in 2012, PPI, amoxicillin and clarithromycin in 2013, and PPI, amoxicillin and rifampin in 2014. Following the first treatment, the isolate was metronidazole and ciprofloxacin/levofloxacin resistant. After the second treatment, the isolate was resistant to metronidazole, ciprofloxacin/levofloxacin and rifampin, developing secondary clarithromycin resistance by A2143G mutation and was susceptible only to tetracycline. After the third treatment, the patient still remained H. pylori positive. Patient's strain was highly virulent (cagA (+) , cagE (+) and vacA s1a/m1/i1). The evolution of the patient's disease was from gastroesophageal reflux disease in 2012 to two duodenal ulcers in 2015. Briefly, the infecting strain showed quadruple antibiotic resistance and a transient amoxicillin resistance. Triple clarithromycin-based treatment induced secondary clarithromycin resistance by A2143G mutation, while rifampin resistance caused the third treatment failure. Several options for the next treatment regimens are discussed. PMID:26634607

  15. Iron-regulated envelope proteins of mycobacteria grown in vitro and their occurrence in Mycobacterium avium and Mycobacterium leprae grown in vivo.

    PubMed

    Sritharan, M; Ratledge, C

    1990-01-01

    Several iron-regulated envelope proteins (IREPs), 11-180 kDa, have been detected in preparations of walls and membranes of Mycobacterium smegmatis, in an armadillo-derived mycobacterium (ADM) and in M. avium. The same sized proteins from M. vacae appeared under both iron-deficient and iron-sufficient growth conditions. Two larger proteins, of 240 and 250 kDa, appeared in the membranes of M. smegmatis and M. avium only when grown iron-sufficiently but were constitutively present in both ADM and M. vaccae. The IREPs from M. smegmatis were not induced under zinc-deficient growth conditions. Three of the four IREPs (14, 21 and 29 kDa) recognized in M. avium grown in vitro were also recovered from membrane fractions of the same strain grown in mice. In addition, these membranes contained both the high-molecular-mass proteins associated with iron-sufficient growth conditions. Membranes of M. leprae, recovered from infected armadillos, showed the faint presence of a possible IREP at 29 kDa and wall preparations showed the presence of a 21-kDa protein. Membranes also contained the two larger proteins at 240 and 250 kDa. An explanation for the simultaneous occurrence of both low-iron-regulated and high-iron-regulated proteins is offered. PMID:2202378

  16. Four thousand years of environmental change and human activity in the Cochabamba Basin, Bolivia

    NASA Astrophysics Data System (ADS)

    Williams, Joseph J.; Gosling, William D.; Coe, Angela L.; Brooks, Stephen J.; Gulliver, Pauline

    The Cochabamba Basin (Bolivia) is on the ancient road network connecting Andean and lowland areas. Little is known about the longevity of this trade route or how people responded to past environmental changes. The eastern end of the Cochabamba valley system constricts at the Vacas Lake District, constraining the road network and providing an ideal location in which to examine past human-environmental interactions. Multi-proxy analysis of sediment from Lake Challacaba has allowed a c. 4000 year environmental history to be reconstructed. Fluctuations in drought tolerant pollen taxa and calcium carbonate indicate two periods of reduced moisture availability ( c. 4000-3370 and c. 2190-1020 cal yr BP) compared to adjacent wetter episodes ( c. 3370-2190 and c. 1020 cal yr BP-present). The moisture fluctuations broadly correlate to El Niño/Southern Oscillation variations reported elsewhere. High charcoal abundance from c. 4000 to 2000 yr ago indicates continuous use of the ancient road network. A decline in charcoal and an increase in dung fungus ( Sporormiella) c. 1340 -1210 cal yr BP, suggests that cultural changes were a major factor in shaping the modern landscape. Despite undisputable impacts of human populations on the Polylepis woodlands today, we see no evidence of woodland clearance in the Challacaba record.

  17. Role of Helicobacter pylori in gastric cancer: advances and controversies.

    PubMed

    Meng, Wenbo; Bai, Bing; Sheng, Liang; Li, Yan; Yue, Ping; Li, Xun; Qiao, Liang

    2015-11-01

    Gastric cancer is one of the most common cancers of digestive system globally and Helicobacter pylori (HP) infection is believed to be a major risk factor. HP can be classified into different types based on the presence and expression level of CagA and VacA, and, when exposed to adverse environment, HP changes its phenotype from helical type to coccoid type, with each having different pathogenicity. The mechanisms of HP-induced gastric carcinogenesis and progression are complicated, including DNA nitration and oxidation induced by mutagenic factors, HP-induced epigenetic modifications, HP-induced disruption of the balance between cell proliferation and apoptosis, and HP-induced cancer cell invasion and metastasis. HP may also affect the biological function of cancer stem cells and induction of cell autophagy. The lipopolysaccharide produced by HP can act through toll-like receptor-4 (TLR-4) to induce gastric mucosal inflammation and is thereby linked to the development of gastric cancer. PMID:26645900

  18. Salt glands in the Jurassic metriorhynchid Geosaurus: implications for the evolution of osmoregulation in Mesozoic marine crocodyliforms.

    PubMed

    Fernández, Marta; Gasparini, Zulma

    2008-01-01

    The presence of salt-excreting glands in extinct marine sauropsids has been long suspected based on skull morphology. Previously, we described for the first time the natural casts of salt-excreting glands in the head of the Jurassic metriorhynchid crocodyliform Geosaurus araucanensis from the Tithonian of the Vaca Muerta Formation in the Neuquén Basin (Argentina). In the present study, salt-excreting glands are identified in three new individuals (adult, a sub-adult and a juvenile) referable to the same species. New material provides significant information on the salt glands form and function and permit integration of evolutionary scenarios proposed on a physiological basis in extant taxa with evidence from the fossil record. G. araucanensis represents an advanced stage of the basic physiological model to marine adaptations in reptiles. G. araucanensis salt glands were hypertrophied. On this basis, it can be hypothesized that these glands had a high excretory capability. This stage implies that G. araucanensis (like extant pelagic reptiles, e.g. cheloniids) could have maintained constant plasma osmolality even when seawater or osmoconforming prey were ingested. A gradual model of marine adaptation in crocodyliforms based on physiology (freshwater to coastal/estuarine to estuarine /marine to pelagic life) is congruent with the phylogeny of crocodyliforms based on skeletal morphology. The fossil record suggests that the stage of marine pelagic adaptation was achieved by the Early Middle Jurassic. Salt gland size in the juvenile suggests that juveniles were, like adults, pelagic. PMID:17712540

  19. Effective treatment of allergic airway inflammation with Helicobacter pylori immunomodulators requires BATF3-dependent dendritic cells and IL-10

    PubMed Central

    Engler, Daniela B.; Reuter, Sebastian; van Wijck, Yolanda; Urban, Sabine; Kyburz, Andreas; Maxeiner, Joachim; Martin, Helen; Yogev, Nir; Waisman, Ari; Gerhard, Markus; Cover, Timothy L.; Taube, Christian; Müller, Anne

    2014-01-01

    The prevalence of allergic asthma and other atopic diseases has reached epidemic proportions in large parts of the developed world. The gradual loss of the human indigenous microbiota has been held responsible for this trend. The bacterial pathogen Helicobacter pylori is a constituent of the normal gastric microbiota whose presence has been inversely linked to allergy and asthma in humans and experimental models. Here we show that oral or i.p. tolerization with H. pylori extract prevents the airway hyperresponsiveness, bronchoalveolar eosinophilia, pulmonary inflammation, and Th2 cytokine production that are hallmarks of allergen-induced asthma in mice. Asthma protection is not conferred by extracts from other enteropathogens and requires a heat-sensitive H. pylori component and the DC-intrinsic production of IL-10. The basic leucine zipper ATF-like 3 (BATF3)-dependent CD103+CD11b− dendritic cell lineage is enriched in the lungs of protected mice and strictly required for protection. Two H. pylori persistence determinants, the γ-glutamyl-transpeptidase GGT and the vacuolating cytotoxin VacA, are required and sufficient for asthma protection and can be administered in purified form to prevent asthma. In conclusion, we provide preclinical evidence for the concept that the immunomodulatory properties of H. pylori can be exploited for tolerization strategies aiming to prevent allergen-induced asthma. PMID:25074917

  20. Helicobacter pylori in gastric carcinogenesis.

    PubMed

    Ahn, Hyo Jun; Lee, Dong Soo

    2015-12-15

    Gastric cancer still is a major concern as the third most common cancer worldwide, despite declining rates of incidence in many Western countries. Helicobacter pylori (H. pylori) is the major cause of gastric carcinogenesis, and its infection insults gastric mucosa leading to the occurrence of atrophic gastritis which progress to intestinal metaplasia, dysplasia, early gastric cancer, and advanced gastric cancer consequently. This review focuses on multiple factors including microbial virulence factors, host genetic factors, and environmental factors, which can heighten the chance of occurrence of gastric adenocarcinoma due to H. pylori infection. Bacterial virulence factors are key components in controlling the immune response associated with the induction of carcinogenesis, and cagA and vacA are the most well-known pathogenic factors. Host genetic polymorphisms contribute to regulating the inflammatory response to H. pylori and will become increasingly important with advancing techniques. Environmental factors such as high salt and smoking may also play a role in gastric carcinogenesis. It is important to understand the virulence factors, host genetic factors, and environmental factors interacting in the multistep process of gastric carcinogenesis. To conclude, prevention via H. pylori eradication and controlling environmental factors such as diet, smoking, and alcohol is an important strategy to avoid H. pylori-associated gastric carcinogenesis. PMID:26690981

  1. Differences in Genotypes of Helicobacter pylori from Different Human Populations

    PubMed Central

    Kersulyte, Dangeruta; Mukhopadhyay, Asish K.; Velapatiño, Billie; Su, WanWen; Pan, ZhiJun; Garcia, Claudia; Hernandez, Virginia; Valdez, Yanet; Mistry, Rajesh S.; Gilman, Robert H.; Yuan, Yuan; Gao, Hua; Alarcón, Teresa; López-Brea, Manuel; Balakrish Nair, G.; Chowdhury, Abhijit; Datta, Simanti; Shirai, Mutsunori; Nakazawa, Teruko; Ally, Reidwaan; Segal, Isidore; Wong, Benjamin C. Y.; Lam, S. K.; Olfat, Farzad O.; Borén, Thomas; Engstrand, Lars; Torres, Olga; Schneider, Roberto; Thomas, Julian E.; Czinn, Steven; Berg, Douglas E.

    2000-01-01

    DNA motifs at several informative loci in more than 500 strains of Helicobacter pylori from five continents were studied by PCR and sequencing to gain insights into the evolution of this gastric pathogen. Five types of deletion, insertion, and substitution motifs were found at the right end of the H. pylori cag pathogenicity island. Of the three most common motifs, type I predominated in Spaniards, native Peruvians, and Guatemalan Ladinos (mixed Amerindian-European ancestry) and also in native Africans and U.S. residents; type II predominated among Japanese and Chinese; and type III predominated in Indians from Calcutta. Sequences in the cagA gene and in vacAm1 type alleles of the vacuolating cytotoxin gene (vacA) of strains from native Peruvians were also more like those from Spaniards than those from Asians. These indications of relatedness of Latin American and Spanish strains, despite the closer genetic relatedness of Amerindian and Asian people themselves, lead us to suggest that H. pylori may have been brought to the New World by European conquerors and colonists about 500 years ago. This thinking, in turn, suggests that H. pylori infection might have become widespread in people quite recently in human evolution. PMID:10809702

  2. Rare Helicobacter pylori Virulence Genotypes in Bhutan.

    PubMed

    Matsunari, Osamu; Miftahussurur, Muhammad; Shiota, Seiji; Suzuki, Rumiko; Vilaichone, Ratha-Korn; Uchida, Tomohisa; Ratanachu-Ek, Thawee; Tshering, Lotay; Mahachai, Varocha; Yamaoka, Yoshio

    2016-01-01

    Both the prevalence of Helicobacter pylori infection and the incidence of gastric cancer are high in Bhutan. The high incidence of atrophic gastritis and gastric cancer suggest the phylogeographic origin of an infection with a more virulent strain of H. pylori. More than 90% of Bhutanese strains possessed the highly virulent East Asian-type CagA and all strains had the most virulent type of vacA (s1 type). More than half also had multiple repeats in East Asian-type CagA, which are rare in other countries and are reported characteristictly found in assciation with atrophic gastritis and gastric cancer consistent with Bhutanese strains having multiple H. pylori virulence factors associated with an increase in gastric cancer risk. Phylogeographic analyses showed that most Bhutanese strains belonged to the East Asian population type with some strains (17.5%) sharing East Asian and Amerindian components. Only 9.5% belonged to the European type consistant with H. pylori in Bhutan representing an intermediate evolutionary stage between H. pylori from European and East Asian countries. PMID:26931643

  3. Pathogenesis of Helicobacter pylori-Related Gastroduodenal Diseases from Molecular Epidemiological Studies

    PubMed Central

    Yamaoka, Yoshio

    2012-01-01

    Helicobacter pylori is a major human pathogen that infects the stomach and produces inflammation that is responsible for various gastroduodenal diseases. Despite the high prevalence of H. pylori infections in Africa and South Asia, the incidence of gastric cancer in these areas is much lower than in other countries. The incidence of gastric cancer also tends to decrease from north to south in East Asia. Data from molecular epidemiological studies show that this variation in different geographic areas could be explained in part by different types of H. pylori virulence factors, especially CagA, VacA, and OipA. H. pylori infection is thought to be involved in both gastric cancer and duodenal ulcer, which are at opposite ends of the disease spectrum. This discrepancy can also be explained in part by another H. pylori factor, DupA, as well as by CagA typing (East Asian type versus Western type). H. pylori has a genome of approximately 1,600 genes; therefore, there might be other novel virulence factors. Because genome wide analyses using whole-genome sequencing technology give a broad view of the genome of H. pylori, we hope that next-generation sequencers will enable us to efficiently investigate novel virulence factors. PMID:22829807

  4. Pathogenesis of Helicobacter pylori-Related Gastroduodenal Diseases from Molecular Epidemiological Studies.

    PubMed

    Yamaoka, Yoshio

    2012-01-01

    Helicobacter pylori is a major human pathogen that infects the stomach and produces inflammation that is responsible for various gastroduodenal diseases. Despite the high prevalence of H. pylori infections in Africa and South Asia, the incidence of gastric cancer in these areas is much lower than in other countries. The incidence of gastric cancer also tends to decrease from north to south in East Asia. Data from molecular epidemiological studies show that this variation in different geographic areas could be explained in part by different types of H. pylori virulence factors, especially CagA, VacA, and OipA. H. pylori infection is thought to be involved in both gastric cancer and duodenal ulcer, which are at opposite ends of the disease spectrum. This discrepancy can also be explained in part by another H. pylori factor, DupA, as well as by CagA typing (East Asian type versus Western type). H. pylori has a genome of approximately 1,600 genes; therefore, there might be other novel virulence factors. Because genome wide analyses using whole-genome sequencing technology give a broad view of the genome of H. pylori, we hope that next-generation sequencers will enable us to efficiently investigate novel virulence factors. PMID:22829807

  5. Therapeutic Vaccination against Helicobacter pylori in the Beagle Dog Experimental Model: Safety, Immunogenicity, and Efficacy

    PubMed Central

    Rossi, Giacomo; Ruggiero, Paolo; Peppoloni, Samuele; Pancotto, Laura; Fortuna, Damiano; Lauretti, Laura; Volpini, Gianfranco; Mancianti, Silvia; Corazza, Michele; Taccini, Ennio; Di Pisa, Francesco; Rappuoli, Rino; Del Giudice, Giuseppe

    2004-01-01

    Helicobacter pylori is a gram-negative bacterium that colonizes the human gastric mucosa causing gastritis and peptic ulcer and increasing the risk of gastric cancer. The efficacy of current antibiotic-based therapies can be limited by problems of patient compliance and increasing antibiotic resistance; the vaccine approach can overcome these limits. The present study describes the therapeutic vaccination of experimentally H. pylori-infected beagle dogs, an animal model that reproduces several aspects of the human infection with H. pylori. The vaccine consisted of three recombinant H. pylori antigens, CagA, VacA, and NAP, formulated at different doses (10, 25, or 50 μg each) with alum and administered intramuscularly either weekly or monthly. No adverse effects were observed after vaccination and a good immunoglobulin G response was generated against each of the three antigens. Bacterial colonization and gastritis were decreased after the completion of the vaccination cycle, especially in the case of the monthly immunization schedule. In conclusion, therapeutic vaccination in the beagle dog model was safe and immunogenic and was able to limit H. pylori colonization and the related gastric pathology. PMID:15155627

  6. Phylogeographic origin of Helicobacter pylori determines host-adaptive responses upon coculture with gastric epithelial cells.

    PubMed

    Sheh, Alexander; Chaturvedi, Rupesh; Merrell, D Scott; Correa, Pelayo; Wilson, Keith T; Fox, James G

    2013-07-01

    While Helicobacter pylori infects over 50% of the world's population, the mechanisms involved in the development of gastric disease are not fully understood. Bacterial, host, and environmental factors play a role in disease outcome. To investigate the role of bacterial factors in H. pylori pathogenesis, global gene expression of six H. pylori isolates was analyzed during coculture with gastric epithelial cells. Clustering analysis of six Colombian clinical isolates from a region with low gastric cancer risk and a region with high gastric cancer risk segregated strains based on their phylogeographic origin. One hundred forty-six genes had increased expression in European strains, while 350 genes had increased expression in African strains. Differential expression was observed in genes associated with motility, pathogenicity, and other adaptations to the host environment. European strains had greater expression of the virulence factors cagA, vacA, and babB and were associated with increased gastric histologic lesions in patients. In AGS cells, European strains promoted significantly higher interleukin-8 (IL-8) expression than did African strains. African strains significantly induced apoptosis, whereas only one European strain significantly induced apoptosis. Our data suggest that gene expression profiles of clinical isolates can discriminate strains by phylogeographic origin and that these profiles are associated with changes in expression of the proinflammatory and protumorigenic cytokine IL-8 and levels of apoptosis in host epithelial cells. These findings support the hypothesis that bacterial factors determined by the phylogeographic origin of H. pylori strains may promote increased gastric disease. PMID:23630959

  7. Helicobacter pylori in gastric carcinogenesis

    PubMed Central

    Ahn, Hyo Jun; Lee, Dong Soo

    2015-01-01

    Gastric cancer still is a major concern as the third most common cancer worldwide, despite declining rates of incidence in many Western countries. Helicobacter pylori (H. pylori) is the major cause of gastric carcinogenesis, and its infection insults gastric mucosa leading to the occurrence of atrophic gastritis which progress to intestinal metaplasia, dysplasia, early gastric cancer, and advanced gastric cancer consequently. This review focuses on multiple factors including microbial virulence factors, host genetic factors, and environmental factors, which can heighten the chance of occurrence of gastric adenocarcinoma due to H. pylori infection. Bacterial virulence factors are key components in controlling the immune response associated with the induction of carcinogenesis, and cagA and vacA are the most well-known pathogenic factors. Host genetic polymorphisms contribute to regulating the inflammatory response to H. pylori and will become increasingly important with advancing techniques. Environmental factors such as high salt and smoking may also play a role in gastric carcinogenesis. It is important to understand the virulence factors, host genetic factors, and environmental factors interacting in the multistep process of gastric carcinogenesis. To conclude, prevention via H. pylori eradication and controlling environmental factors such as diet, smoking, and alcohol is an important strategy to avoid H. pylori-associated gastric carcinogenesis. PMID:26690981

  8. Salt glands in the Jurassic metriorhynchid Geosaurus: implications for the evolution of osmoregulation in Mesozoic marine crocodyliforms

    NASA Astrophysics Data System (ADS)

    Fernández, Marta; Gasparini, Zulma

    2008-01-01

    The presence of salt-excreting glands in extinct marine sauropsids has been long suspected based on skull morphology. Previously, we described for the first time the natural casts of salt-excreting glands in the head of the Jurassic metriorhynchid crocodyliform Geosaurus araucanensis from the Tithonian of the Vaca Muerta Formation in the Neuquén Basin (Argentina). In the present study, salt-excreting glands are identified in three new individuals (adult, a sub-adult and a juvenile) referable to the same species. New material provides significant information on the salt glands form and function and permit integration of evolutionary scenarios proposed on a physiological basis in extant taxa with evidence from the fossil record. G. araucanensis represents an advanced stage of the basic physiological model to marine adaptations in reptiles. G. araucanensis salt glands were hypertrophied. On this basis, it can be hypothesized that these glands had a high excretory capability. This stage implies that G. araucanensis (like extant pelagic reptiles, e.g. cheloniids) could have maintained constant plasma osmolality even when seawater or osmoconforming prey were ingested. A gradual model of marine adaptation in crocodyliforms based on physiology (freshwater to coastal/estuarine to estuarine /marine to pelagic life) is congruent with the phylogeny of crocodyliforms based on skeletal morphology. The fossil record suggests that the stage of marine pelagic adaptation was achieved by the Early Middle Jurassic. Salt gland size in the juvenile suggests that juveniles were, like adults, pelagic.

  9. The engineering and geological constraints of the intraslope basins and submarine canyons of the northwestern Gulf of Mexico

    SciTech Connect

    Bryant, W.R.; Yuh Liu, J.; Ponthier, J.

    1995-10-01

    It is well realized that future hydrocarbon discoveries on the upper and lower continental slope and rise off Texas and Louisiana necessitate innovative methods for the construction of platforms and pipelines in a very difficult engineering and complex geological environment. There are 105 intraslope basins and 5 major submarine canyons on the continental slope of the northwestern Gulf of Mexico, many of which may be prime targets for hydrocarbon production. Examination of the physiographic, geophysical and geotechnical characteristics of the intraslope basins of Pigmy and Vaca basins and the Alaminos submarine canyon are used as examples to typify the various engineering and geological constraints that are most likely to be encountered on the continental slope and rise and along the Sigsbee Escarpment in the northwestern Gulf of Mexico. High-resolution bathymetry identifies such constraints as high-angle intraslope basin walls, walls that exceed 40 degrees are not uncommon. Sediment slumps and other instabilities, such as long-term sediment creep and other affects of halokenesis and contemporaneous faulting, are illustrated and evaluated from high-resolution geophysics. The small canyons and large gullies that dissect the parameter flanks of Alaminos Canyon, that may be the results of both recent and old turbidity currents and debris flows, are structures that require engineering consideration in the implement of seafloor structures in, near or down slope of these features.

  10. V-ATPase and osmotic imbalances activate endolysosomal LC3 lipidation.

    PubMed

    Florey, Oliver; Gammoh, Noor; Kim, Sung Eun; Jiang, Xuejun; Overholtzer, Michael

    2015-01-01

    Recently a noncanonical activity of autophagy proteins has been discovered that targets lipidation of microtubule-associated protein 1 light chain 3 (LC3) onto macroendocytic vacuoles, including macropinosomes, phagosomes, and entotic vacuoles. While this pathway is distinct from canonical autophagy, the mechanism of how these nonautophagic membranes are targeted for LC3 lipidation remains unclear. Here we present evidence that this pathway requires activity of the vacuolar-type H(+)-ATPase (V-ATPase) and is induced by osmotic imbalances within endolysosomal compartments. LC3 lipidation by this mechanism is induced by treatment of cells with the lysosomotropic agent chloroquine, and through exposure to the Heliobacter pylori pore-forming toxin VacA. These data add novel mechanistic insights into the regulation of noncanonical LC3 lipidation and its associated processes, including LC3-associated phagocytosis (LAP), and demonstrate that the widely and therapeutically used drug chloroquine, which is conventionally used to inhibit autophagy flux, is an inducer of LC3 lipidation. PMID:25484071

  11. Molecular pathogenesis of Helicobacter pylori infection: the role of bacterial virulence factors.

    PubMed

    Molnar, Bela; Galamb, Orsolya; Sipos, Ferenc; Leiszter, Katalin; Tulassay, Zsolt

    2010-01-01

    Helicobacter pylori is one of the most common pathogens affecting humankind, infecting approximately 50% of the world's population. Of those infected, many will develop asymptomatic gastritis, but 10% develop gastric or duodenal ulcers. The clinical outcome of the infection may involve a combination of bacterial factors, host factors and environmental factors. In the process of development of gastritis, ulceration and cancer, several cellular and molecular steps follow each other. Infection, acid survival, adhesion, cytotoxicity, epithelial cell turnover changes, inflammation, regeneration or pathological alteration towards erosions, ulceration, and cancer can be observed on the cellular level. Bacterial factors like urease, AmiE, AmiF, hydrogenase and arginase are needed for survival in the acidic gastric environment. The bacterial flagellae are essential to move the bacteria towards the epithelial surface. Adhesive factors like BabA, SabA and ureaseA are necessary for adhesion against MHC-II complexes and Le antigens. The bacteria VacA and CagA are cytotoxic factors. The Cag type IV secretion system delivers these proteins inside the epithelial cells. After disruption of epithelial cell junctions, the bacteria can pass through the gastric wall facing direct immune response from neutrophils, lymphocytes, mast cells and dendritic cells. This review describes and summarizes our present molecular biological information and knowledge about the Helicobacter infective component, cell functions and processes. The possible role of host counter responses and interactions with gastric epithelia and immune cells are also detailed. PMID:21088410

  12. Helicobacter pylori and gastric cancer in the Middle East: a new enigma?

    PubMed

    Hussein, Nawfal R

    2010-07-14

    The Middle East is the home of ethnic groups from three main backgrounds: Semitic (Arabs and Jews), Indo-European (Persians and Kurdish) and Turkic (Turkish and Turkmens). Its geographic location, which has been under continuous influences from Asia, Europe and Africa, has made it an ideal site for epidemiological studies on Helicobacter pylori (H. pylori) infection and genotyping. The gastric cancer rate differs in this region from very high in Iran (26.1/10(5)) to low in Israel (12.5/10(5)) and very low in Egypt (3.4/10(5)). Epidemiological studies showed that the prevalence of H. pylori is almost similar in those countries with a high level of infection in childhood. Importantly, the frequency of vacA s1 and m1 regions and cagA+ genotypes were higher in non Semitic populations who inhabit the North than Semitic populations, the inhabitants of Southern parts of the Middle East. H. pylori infection prevalence, distribution pattern of virulence factors, diet and smoking could not have explained the difference in cancer rate. This reflects the multifactorial aetiology of gastric cancer and suggests that H. pylori infection does not always directly correlate with the risk for gastrointestinal disease, such as gastric cancer. Further detailed investigations and international comparative studies of each risk factor need to be performed to investigate whether this represents a true enigma. PMID:20614477

  13. Upper Jurassic ramp carbonate and associated evaporite, Neuquen Province, Argentina

    SciTech Connect

    Nickelsen, B.H.; Merrill, D.A.

    1986-05-01

    The Oxfordian La Manga Limestone (10-65 m) and overlying Auquilco Gypsum (315 m maximum thickness) crop out along the west flank of the Neuquen basin, Neuquen Province, Argentina (36/sup 0/40/sup 0/S lat.). The contact with the underlying Lotena Sandstone is gradational, and both formations are cut by the Late Jurassic Araucanian angular unconformity. Seven lithofacies have been identified within sections measured through the entire interval along the northeast to southwest trending, 30-km long Sierra de la Vaca Muerta ridge (38/sup 0/30'-39/sup 0/S). The La Manga Limestone is interpreted as a temperate ramp carbonate that developed over the Lotena Formation siliciclastic shelf. Interpretations of lithofacies from southwest to northeast are: behind-barrier subtidal lagoon with washovers; coral and red algae biostromes; ooid and peloid sand shoals; downslope wackestone and packstone mud mounds; and deep-water carbonate turbidites. A minor regression separates La Manga and Auquilco Formations. Lithofacies of the Auquilco Formation indicate a shallowing-up sequence comprised of initially deep (hundreds of meters) subaqueous evaporite deposition followed by shallow, subtidal carbonate peloidal and shell fragment grainstones and evaporites. Thickness of the subaqueous evaporite gives an order of magnitude estimate of Auquilco basin depths of a few hundred meters at most. The Neuquen basin has an intermediate proportion of carbonate in comparison to relatively carbonate-poor basins to the south and carbonate-rich basins to the north.

  14. "Non-Toxic" Proteins of the Botulinum Toxin Complex Exert In-vivo Toxicity.

    PubMed

    Miyashita, Shin-Ichiro; Sagane, Yoshimasa; Suzuki, Tomonori; Matsumoto, Takashi; Niwa, Koichi; Watanabe, Toshihiro

    2016-01-01

    The botulinum neurotoxin (BoNT) causes muscle paralysis and is the most potent toxin in nature. BoNT is associated with a complex of auxiliary "Non-Toxic" proteins, which constitute a large-sized toxin complex (L-TC). However, here we report that the "Non-Toxic" complex of serotype D botulinum L-TC, when administered to rats, exerts in-vivo toxicity on small-intestinal villi. Moreover, Serotype C and D of the "Non-Toxic" complex, but not BoNT, induced vacuole-formation in a rat intestinal epithelial cell line (IEC-6), resulting in cell death. Our results suggest that the vacuole was formed in a manner distinct from the mechanism by which Helicobacter pylori vacuolating toxin (VacA) and Vibrio cholerae haemolysin induce vacuolation. We therefore hypothesise that the serotype C and D botulinum toxin complex is a functional hybrid of the neurotoxin and vacuolating toxin (VT) which arose from horizontal gene transfer from an ancestral BoNT-producing bacterium to a hypothetical VT-producing bacterium. PMID:27507612

  15. Rare Helicobacter pylori Virulence Genotypes in Bhutan

    PubMed Central

    Matsunari, Osamu; Miftahussurur, Muhammad; Shiota, Seiji; Suzuki, Rumiko; Vilaichone, Ratha-korn; Uchida, Tomohisa; Ratanachu-ek, Thawee; Tshering, Lotay; Mahachai, Varocha; Yamaoka, Yoshio

    2016-01-01

    Both the prevalence of Helicobacter pylori infection and the incidence of gastric cancer are high in Bhutan. The high incidence of atrophic gastritis and gastric cancer suggest the phylogeographic origin of an infection with a more virulent strain of H. pylori. More than 90% of Bhutanese strains possessed the highly virulent East Asian-type CagA and all strains had the most virulent type of vacA (s1 type). More than half also had multiple repeats in East Asian-type CagA, which are rare in other countries and are reported characteristictly found in assciation with atrophic gastritis and gastric cancer consistent with Bhutanese strains having multiple H. pylori virulence factors associated with an increase in gastric cancer risk. Phylogeographic analyses showed that most Bhutanese strains belonged to the East Asian population type with some strains (17.5%) sharing East Asian and Amerindian components. Only 9.5% belonged to the European type consistant with H. pylori in Bhutan representing an intermediate evolutionary stage between H. pylori from European and East Asian countries. PMID:26931643

  16. Diagnóstico diferencial en la encefalitis por anticuerpos contra el receptor NMDA

    PubMed Central

    González-Valcárcel, J.; Rosenfeld, M.R.; Dalmau, J.

    2011-01-01

    Resumen Introducción La encefalitis por anticuerpos contra el receptor de NMDA (NMDAR) suele desarrollarse como un síndrome característico de evolución multifásica y diagnóstico diferencial amplio. Pacientes Presentamos a 2 pacientes diagnosticadas de encefalitis por anticuerpos NMDAR con un cuadro clínico típico, pero que inicialmente señaló otras etiologías. Discusión La afectación frecuente de pacientes jóvenes con manifestaciones psiquiátricas prominentes indica frecuentemente otras consideraciones diagnósticas; las más frecuentes son las encefalitis virales, los procesos psiquiátricos y el síndrome neuroléptico maligno. Varios síndromes previamente definidos de manera parcial o descriptiva en adultos y pacientes pediátricos probablemente eran casos de encefalitis anti-NMDAR. Conclusiones La encefalitis anti-NMDAR debe considerarse en pacientes jóvenes con manifestaciones psiquiátricas subagudas, movimientos anormales y alteraciones autonómicas. La caracterización clínica e inmunológica de esta enfermedad ha llevado a la identificación de nuevos anticuerpos que afectan a procesos de memoria, aprendizaje, conducta y psicosis. PMID:20964986

  17. Review: prospects for the use of extracts and polysaccharides from marine algae to prevent and treat the diseases caused by Helicobacter pylori.

    PubMed

    Besednova, Natalya N; Zaporozhets, Tatyana S; Somova, Larisa M; Kuznetsova, Tatyana A

    2015-04-01

    Helicobacter pylori possesses a broad spectrum of pathogenic factors that allow it to survive and colonize the gastric mucosa, and thus, the pathogenetic targets, which have the same diversity, require search for and the development of alternative, effective, and innocuous means for the eradication of H. pylori. In recent years, fucoidans have been extensively studied due to the numerous interesting biological activities, including the anti-adhesive, anti-oxidative, antitoxic, immunomodulatory, anticoagulant, and anti-infection effects. This review summarizes the data on the effects of extracts and sulfated polysaccharides of marine algae, mainly fucoidans, on pathogenic targets in Helicobacter infection. The pathogenetic targets for therapeutic agents after H. pylori infection, such as flagellas, urease, and other enzymes, including adhesins, cytotoxin A (VacA), phospholipase, and L-8, are characterized here. The main target for the sulfated polysaccharides of seaweed is cell receptors of the gastric mucosa. This review presents the published data about the pleiotropic anti-inflammatory effects of polysaccharides on the gastric mucosa. It is known that fucoidan and other sulfated polysaccharides from algae have anti-ulcer effects, prevent the adhesion of H. pylori to, and reduce the formation of biofilm. The authors speculate that the effect of sulfated polysaccharides on the infectious process caused by H. pylori is related to their action on innate and adaptive immunity cells, and also anti-oxidant and antitoxic potential. Presented in the review are materials indicated for the study of extracts and sulfated polysaccharides from seaweed during H. pylori infection, as these compounds are characterized by multimodality actions. Based on the analysis of literary materials in recent years, the authors concluded that fucoidan can be attributed to the generation of new candidates to create drugs intended for the inclusion in the scheme of eradication therapy of

  18. Helicobacter pylori in vegetables and salads: genotyping and antimicrobial resistance properties.

    PubMed

    Yahaghi, Emad; Khamesipour, Faham; Mashayekhi, Fatemeh; Safarpoor Dehkordi, Farhad; Sakhaei, Mohammad Hossein; Masoudimanesh, Mojtaba; Khameneie, Maryam Khayyat

    2014-01-01

    From a clinical and epidemiological perspective, it is important to know which genotypes and antibiotic resistance patterns are present in H. pylori strains isolated from salads and vegetables. Therefore, the present investigation was carried out to find this purpose. Three hundred eighty washed and unwashed vegetable samples and fifty commercial and traditional salad samples were collected from Isfahan, Iran. Samples were cultured and those found positive for H. pylori were analyzed using PCR. Antimicrobial susceptibility testing was performed using disk diffusion method. Seven out of 50 (14%) salad and 52 out of 380 (13.68%) vegetable samples harbored H. pylori. In addition, leek, lettuce, and cabbage were the most commonly contaminated samples (30%). The most prevalent virulence genes were oipA (86.44%) and cagA (57.625). VacA s1a (37.28%) and iceA1 (47.45%) were the most prevalent genotypes. Forty different genotypic combinations were recognized. S1a/cagA+/iceA1/oipA+ (33.89%), s1a/cagA+/iceA2/oipA (30.50%), and m1a/cagA+/iceA1/oipA+ (28.81%) were the most prevalent combined genotypes. Bacterial strains had the highest levels of resistance against metronidazole (77.96%), amoxicillin (67.79%), and ampicillin (61.01%). High similarity in the genotyping pattern of H. pylori among vegetable and salad samples and human specimens suggests that vegetable and salads may be the sources of the bacteria. PMID:25184146

  19. Electron microscopic, genetic and protein expression analyses of Helicobacter acinonychis strains from a Bengal tiger.

    PubMed

    Tegtmeyer, Nicole; Rivas Traverso, Francisco; Rohde, Manfred; Oyarzabal, Omar A; Lehn, Norbert; Schneider-Brachert, Wulf; Ferrero, Richard L; Fox, James G; Berg, Douglas E; Backert, Steffen

    2013-01-01

    Colonization by Helicobacter species is commonly noted in many mammals. These infections often remain unrecognized, but can cause severe health complications or more subtle host immune perturbations. The aim of this study was to isolate and characterize putative novel Helicobacter spp. from Bengal tigers in Thailand. Morphological investigation (Gram-staining and electron microscopy) and genetic studies (16SrRNA, 23SrRNA, flagellin, urease and prophage gene analyses, RAPD DNA fingerprinting and restriction fragment polymorphisms) as well as Western blotting were used to characterize the isolated Helicobacters. Electron microscopy revealed spiral-shaped bacteria, which varied in length (2.5-6 µm) and contained up to four monopolar sheathed flagella. The 16SrRNA, 23SrRNA, sequencing and protein expression analyses identified novel H. acinonychis isolates closely related to H. pylori. These Asian isolates are genetically very similar to H. acinonychis strains of other big cats (cheetahs, lions, lion-tiger hybrid and other tigers) from North America and Europe, which is remarkable in the context of the great genetic diversity among worldwide H. pylori strains. We also found by immunoblotting that the Bengal tiger isolates express UreaseA/B, flagellin, BabA adhesin, neutrophil-activating protein NapA, HtrA protease, γ-glutamyl-transpeptidase GGT, Slt lytic transglycosylase and two DNA transfer relaxase orthologs that were known from H. pylori, but not the cag pathogenicity island, nor CagA, VacA, SabA, DupA or OipA proteins. These results give fresh insights into H. acinonychis genetics and the expression of potential pathogenicity-associated factors and their possible pathophysiological relevance in related gastric infections. PMID:23940723

  20. Electron Microscopic, Genetic and Protein Expression Analyses of Helicobacter acinonychis Strains from a Bengal Tiger

    PubMed Central

    Tegtmeyer, Nicole; Rivas Traverso, Francisco; Rohde, Manfred; Oyarzabal, Omar A.; Lehn, Norbert; Schneider-Brachert, Wulf; Ferrero, Richard L.; Fox, James G.; Berg, Douglas E.; Backert, Steffen

    2013-01-01

    Colonization by Helicobacter species is commonly noted in many mammals. These infections often remain unrecognized, but can cause severe health complications or more subtle host immune perturbations. The aim of this study was to isolate and characterize putative novel Helicobacter spp. from Bengal tigers in Thailand. Morphological investigation (Gram-staining and electron microscopy) and genetic studies (16SrRNA, 23SrRNA, flagellin, urease and prophage gene analyses, RAPD DNA fingerprinting and restriction fragment polymorphisms) as well as Western blotting were used to characterize the isolated Helicobacters. Electron microscopy revealed spiral-shaped bacteria, which varied in length (2.5–6 µm) and contained up to four monopolar sheathed flagella. The 16SrRNA, 23SrRNA, sequencing and protein expression analyses identified novel H. acinonychis isolates closely related to H. pylori. These Asian isolates are genetically very similar to H. acinonychis strains of other big cats (cheetahs, lions, lion-tiger hybrid and other tigers) from North America and Europe, which is remarkable in the context of the great genetic diversity among worldwide H. pylori strains. We also found by immunoblotting that the Bengal tiger isolates express UreaseA/B, flagellin, BabA adhesin, neutrophil-activating protein NapA, HtrA protease, γ-glutamyl-transpeptidase GGT, Slt lytic transglycosylase and two DNA transfer relaxase orthologs that were known from H. pylori, but not the cag pathogenicity island, nor CagA, VacA, SabA, DupA or OipA proteins. These results give fresh insights into H. acinonychis genetics and the expression of potential pathogenicity-associated factors and their possible pathophysiological relevance in related gastric infections. PMID:23940723

  1. Classification of mafic clasts from mesosiderites: Implications for endogenous igneous processes

    SciTech Connect

    Rubin, A.E. ); Mittlefehldt, D.W. )

    1992-02-01

    The authors have analyzed thirteen igneous pebbles from the Vaca Muerta, EET87500, and Bondoc mesosiderites by electron microprobe and instrumental neutron activation and combined these data with literature data for forty-three analyzed mesosiderite clasts. They classify these well-characterized clasts into the following five principal groups: (1) Polygenic and monogenic cumulates (39%) are coarse-grained gabbros that are highly depleted in incompatible elements (relative to H chondrites); they formed at moderate depth either as residues of low-degree partial melting of pre-existing cumulate eucrites or as cumulates from parent melts similar to cumulate eucrites. (2) Polygenic basalts (30%) are finer-grained rocks with positive europium anomalies, La/Lu ratios < 1, and lower rare earth element abundances than basaltic eucrites. It seems likely that these rocks were formed near their parent body surface by remelting mixtures of major amounts of basaltic eucrites and lesser amounts of cumulate eucrites. (3) Quench-textured rocks comprise two compositional groups, (a) those which resemble basaltic eucrites (5%), and (b) those which resemble cumulate eucrites (2%). The quench-textured rocks are probably monogenic; they formed most likely when small-scale impacts at their parent body surface totally melted small amounts of basaltic or cumulate eucrite material. (4) Monogenic basalts (11%) resemble basaltic eucrites and formed by endogenous igneous processes on the mesosiderite parent body (MPB). (5) Ultramafic rocks are cumulates consisting mainly of large crystals of orthopyroxene (9%) or olivine (4%). Orthopyroxenite clasts closely resemble diogenites and were formed most likely by endogenous igneous processes.

  2. Gastric cancer in Africa: what do we know about incidence and risk factors?

    PubMed

    Asombang, Akwi W; Kelly, Paul

    2012-02-01

    Gastric cancer is a major contributor to mortality worldwide, yet its incidence varies widely around the world in a way which our current understanding of aetiology cannot fully explain. Incidence data from Africa are weak, reflecting poor diagnostic resources, but there are firm data on intestinal metaplasia and gastric atrophy which are important steps in the carcinogenesis pathway. The available registry data suggest that incidence is unlikely to be dramatically different from Europe or North America. Helicobacter pylori infection is an important permissive factor in the development of cancer, but H. pylori seroprevalence is high all over Africa and cannot clearly be correlated with cancer. However, there is evidence that specific bacterial virulence genes, particularly vacA and iceA allele1, do contribute to cancer risk. Intestinal metaplasia and gastric atrophy have been the focus of twelve studies and are common in Africa. Epstein-Barr virus, which causes 10% of cancer worldwide, is the focus of only one African study. Work in other continents demonstrates that other risk factors apply only to one or other of the two major histological types, intestinal and diffuse. Diet, smoking, alcohol and salt intake predispose to the intestinal type of cancer, but genetic factors predispose to the diffuse type. There is a pressing need for information on the histological types occurring in Africa, and their associated risk factors. Most urgently, information on dietary predisposition to cancer is required to inform public health policy with respect to the demographic transition (urbanisation and lifestyle changes) which is occurring all over the continent. PMID:22136952

  3. Microbial Disruption of Autophagy Alters Expression of the RISC Component AGO2, a Critical Regulator of the miRNA Silencing Pathway

    PubMed Central

    Sibony, Michal; Abdullah, Majd; Greenfield, Laura; Raju, Deepa; Wu, Ted; Rodrigues, David M.; Galindo-Mata, Esther; Mascarenhas, Heidi; Philpott, Dana J.; Silverberg, Mark S.

    2015-01-01

    Background: Autophagy is implicated in Crohn's disease (CD) pathogenesis. Recent evidence suggests autophagy regulates the microRNA (miRNA)-induced silencing complex (miRISC). Therefore, autophagy may play a novel role in CD by regulating expression of miRISC, thereby altering miRNA silencing. As microbes associated with CD can alter autophagy, we hypothesized that microbial disruption of autophagy affects the critical miRISC component AGO2. Methods: AGO2 expression was assessed in epithelial and immune cells, and intestinal organoids with disrupted autophagy. Microarray technology was used to determine the expression of downstream miRNAs in cells with defective autophagy. Results: Increased AGO2 was detected in autophagy-deficient ATG5−/− and ATG16−/− mouse embryonic fibroblast cells (MEFs) in comparison with wild-type MEFs. Chemical agents and VacA toxin, which disrupt autophagy, increased AGO2 expression in MEFs, epithelial cells lines, and human monocytes, respectively. Increased AGO2 was also detected in ATG7−/− intestinal organoids, in comparison with wild-type organoids. Five miRNAs were differentially expressed in autophagy-deficient MEFs. Pathway enrichment analysis of the differentially expressed miRNAs implicated signaling pathways previously associated with CD. Conclusions: Taken together, our results suggest that autophagy is involved in the regulation of the critical miRISC component AGO2 in epithelial and immune cells and primary intestinal epithelial cells. We propose a mechanism by which autophagy alters miRNA expression, which likely impacts the regulation of CD-associated pathways. Furthermore, as enteric microbial products can manipulate autophagy and AGO2, our findings suggest a novel mechanism by which enteric microbes could influence miRNA to promote disease. PMID:26332312

  4. Vacuoles of Candida yeast as a specialized niche for Helicobacter pylori.

    PubMed

    Siavoshi, Farideh; Saniee, Parastoo

    2014-05-14

    Helicobacter pylori (H. pylori) are resistant to hostile gastric environments and antibiotic therapy, reflecting the possibility that they are protected by an ecological niche, such as inside the vacuoles of human epithelial and immune cells. Candida yeast may also provide such an alternative niche, as fluorescently labeled H. pylori were observed as fast-moving and viable bacterium-like bodies inside the vacuoles of gastric, oral, vaginal and foodborne Candida yeasts. In addition, H. pylori-specific genes and proteins were detected in samples extracted from these yeasts. The H. pylori present within these yeasts produce peroxiredoxin and thiol peroxidase, providing the ability to detoxify oxygen metabolites formed in immune cells. Furthermore, these bacteria produce urease and VacA, two virulence determinants of H. pylori that influence phago-lysosome fusion and bacterial survival in macrophages. Microscopic observations of H. pylori cells in new generations of yeasts along with amplification of H. pylori-specific genes from consecutive generations indicate that new yeasts can inherit the intracellular H. pylori as part of their vacuolar content. Accordingly, it is proposed that yeast vacuoles serve as a sophisticated niche that protects H. pylori against the environmental stresses and provides essential nutrients, including ergosterol, for its growth and multiplication. This intracellular establishment inside the yeast vacuole likely occurred long ago, leading to the adaptation of H. pylori to persist in phagocytic cells. The presence of these bacteria within yeasts, including foodborne yeasts, along with the vertical transmission of yeasts from mother to neonate, provide explanations for the persistence and propagation of H. pylori in the human population. This Topic Highlight reviews and discusses recent evidence regarding the evolutionary adaptation of H. pylori to thrive in host cell vacuoles. PMID:24833856

  5. A Novel Line Immunoassay Based on Recombinant Virulence Factors Enables Highly Specific and Sensitive Serologic Diagnosis of Helicobacter pylori Infection

    PubMed Central

    Formichella, Luca; Romberg, Laura; Bolz, Christian; Vieth, Michael; Geppert, Michael; Göttner, Gereon; Nölting, Christina; Walter, Dirk; Schepp, Wolfgang; Schneider, Arne; Ulm, Kurt; Wolf, Petra; Busch, Dirk H.; Soutschek, Erwin

    2013-01-01

    Helicobacter pylori colonizes half of the world's population, and infection can lead to ulcers, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma. Serology is the only test applicable for large-scale, population-based screening, but current tests are hampered by a lack of sensitivity and/or specificity. Also, no serologic test allows the differentiation of type I and type II strains, which is important for predicting the clinical outcome. H. pylori virulence factors have been associated with disease, but direct assessment of virulence factors requires invasive methods to obtain gastric biopsy specimens. Our work aimed at the development of a highly sensitive and specific, noninvasive serologic test to detect immune responses to important H. pylori virulence factors. This line immunoassay system (recomLine) is based on recombinant proteins. For this assay, six highly immunogenic virulence factors (CagA, VacA, GroEL, gGT, HcpC, and UreA) were expressed in Escherichia coli, purified, and immobilized to nitrocellulose membranes to detect serological immune responses in patient's sera. For the validation of the line assay, a cohort of 500 patients was screened, of which 290 (58.0%) were H. pylori negative and 210 (42.0%) were positive by histology. The assay showed sensitivity and specificity of 97.6% and 96.2%, respectively, compared to histology. In direct comparison to lysate blotting and enzyme-linked immunosorbent assay (ELISA), the recomLine assay had increased discriminatory power. For the assessment of individual risk for gastrointestinal disease, the test must be validated in a larger and defined patient cohort. Taking the data together, the recomLine assay provides a valuable tool for the diagnosis of H. pylori infection. PMID:24006137

  6. Microevolution of Virulence-Related Genes in Helicobacter pylori Familial Infection

    PubMed Central

    Furuta, Yoshikazu; Konno, Mutsuko; Osaki, Takako; Yonezawa, Hideo; Ishige, Taichiro; Imai, Misaki; Shiwa, Yuh; Shibata-Hatta, Mari; Kanesaki, Yu; Yoshikawa, Hirofumi; Kamiya, Shigeru; Kobayashi, Ichizo

    2015-01-01

    Helicobacter pylori, a bacterial pathogen that can infect human stomach causing gastritis, ulcers and cancer, is known to have a high degree of genome/epigenome diversity as the result of mutation and recombination. The bacteria often infect in childhood and persist for the life of the host. One of the reasons of the rapid evolution of H. pylori is that it changes its genome drastically for adaptation to a new host. To investigate microevolution and adaptation of the H. pylori genome, we undertook whole genome sequencing of the same or very similar sequence type in multi-locus sequence typing (MLST) with seven genes in members of the same family consisting of parents and children in Japan. Detection of nucleotide substitutions revealed likely transmission pathways involving children. Nonsynonymous (amino acid changing) mutations were found in virulence-related genes (cag genes, vacA, hcpDX, tnfα, ggt, htrA and the collagenase gene), outer membrane protein (OMP) genes and other cell surface-related protein genes, signal transduction genes and restriction-modification genes. We reconstructed various pathways by which H. pylori can adapt to a new human host, and our results raised the possibility that the mutational changes in virulence-related genes have a role in adaptation to a child host. Changes in restriction-modification genes might remodel the methylome and transcriptome to help adaptation. This study has provided insights into H. pylori transmission and virulence and has implications for basic research as well as clinical practice. PMID:25978460

  7. Piperine treatment suppresses Helicobacter pylori toxin entry in to gastric epithelium and minimizes β-catenin mediated oncogenesis and IL-8 secretion in vitro.

    PubMed

    Tharmalingam, Nagendran; Park, Min; Lee, Min Ho; Woo, Hyun Jun; Kim, Hyun Woo; Yang, Ji Yeong; Rhee, Ki-Jong; Kim, Jong-Bae

    2016-01-01

    Helicobacter pylori related gastric cancer initiation has been studied widely. The objective of our present study was to evaluate the effect of a single compound piperine on H. pylori infection and its anti-inflammatory and anti-cancer effects in vitro. Cytotoxicity was tested by Ez-cytox cell viability assay kit. Effects of piperine on H. pylori toxin gene expression and IL-8 expression in mammalian cells during infection were assessed by RT-PCR. Effects of piperine on toxin entry into host cells, E-cadherin cleavage by H. pylori, and the changes in H. pylori mediated β-catenin expression and IL-8 secretion were determined by immunoblotting. Piperine treatment restrained the entry of CagA and VacA into AGS cells. Piperine administration in H. pylori infection reduced E-cadherin cleavage in stomach epithelium. In addition, H. pylori induced β-catenin up-regulation was reduced. Piperine administration impaired IL-8 secretion in H. pylori-infected gastric epithelial cells. As we reported previously piperine restrained H. pylori motility. The possible reason behind the H. pylori inhibition mechanism of piperine could be the dwindled motility, which weakened H. pylori adhesion to gastric epithelial cells. The reduced adhesion decreased the toxin entry thereby secreting less amount of IL-8. In addition, piperine treatment suppressed H. pylori protease led to reduction of E-cadherin cleavage and β-catenin expression resulting in diminished β-catenin translocation into the nucleus thus decreasing the risk of oncogenesis. To our knowledge, this is the preliminary report of piperine mediated H. pylori infection control on gastric epithelial cells in-vitro. PMID:27158376

  8. Ulcerogenic Helicobacter pylori Strains Isolated from Children: A Contribution to Get Insight into the Virulence of the Bacteria

    PubMed Central

    Vitoriano, Inês; Saraiva-Pava, Kathy D.; Rocha-Gonçalves, Alexandra; Santos, Andrea; Lopes, Ana I.; Oleastro, Mónica; Roxo-Rosa, Mónica

    2011-01-01

    Infection with Helicobacter pylori is the major cause for the development of peptic ulcer disease (PUD). In children, with no other etiology for the disease, this rare event occurs shortly after infection. In these young patients, habits of smoking, diet, consumption of alcohol and non-steroid anti-inflammatory drugs and stress, in addition to the genetic susceptibility of the patient, represent a minor influence. Accordingly, the virulence of the implicated H. pylori strain should play a crucial role in the development of PUD. Corroborating this, our in vitro infection assays comparing a pool of five H. pylori strains isolated from children with PUD to a pool of five other pediatric clinical isolates associated with non-ulcer dyspepsia (NUD) showed the greater ability of PUD strains to induce a marked decrease in the viability of gastric cells and to cause severe damage in the cells cytoskeleton as well as an impairment in the production/secretion of mucins. To uncover virulence features, we compared the proteome of these two groups of H. pylori strains. Two-dimensional gel electrophoresis followed by mass-spectrometry allowed us to detect 27 differentially expressed proteins between them. In addition to the presence of genes encoding well established virulence factors, namely cagA, vacAs1, oipA “on” status, homB and jhp562 genes, the pediatric ulcerogenic strains shared a proteome profile characterized by changes in the abundance of: motility-associated proteins, accounting for higher motility; antioxidant proteins, which may confer increased resistance to inflammation; and enzymes involved in key steps in the metabolism of glucose, amino acids and urea, which may be advantageous to face fluctuations of nutrients. In conclusion, the enhanced virulence of the pediatric ulcerogenic H. pylori strains may result from a synergy between their natural ability to better adapt to the hostile human stomach and the expression of the established virulence factors. PMID

  9. Helicobacter pylori induces miR-155 in T cells in a cAMP-Foxp3-dependent manner.

    PubMed

    Fassi Fehri, Lina; Koch, Manuel; Belogolova, Elena; Khalil, Hany; Bolz, Christian; Kalali, Behnam; Mollenkopf, Hans J; Beigier-Bompadre, Macarena; Karlas, Alexander; Schneider, Thomas; Churin, Yuri; Gerhard, Markus; Meyer, Thomas F

    2010-01-01

    Amongst the most severe clinical outcomes of life-long infections with Helicobacter pylori is the development of peptic ulcers and gastric adenocarcinoma--diseases often associated with an increase of regulatory T cells. Understanding H. pylori-driven regulation of T cells is therefore of crucial clinical importance. Several studies have defined mammalian microRNAs as key regulators of the immune system and of carcinogenic processes. Hence, we aimed here to identify H. pylori-regulated miRNAs, mainly in human T cells. MicroRNA profiling of non-infected and infected human T cells revealed H. pylori infection triggers miR-155 expression in vitro and in vivo. By using single and double H. pylori mutants and the corresponding purified enzymes, the bacterial vacuolating toxin A (VacA) and gamma-glutamyl transpeptidase (GGT) plus lipopolysaccharide (LPS) tested positive for their ability to regulate miR-155 and Foxp3 expression in human lymphocytes; the latter being considered as the master regulator and marker of regulatory T cells. RNAi-mediated knockdown (KD) of the Foxp3 transcription factor in T cells abolished miR-155 expression. Using adenylate cyclase inhibitors, the miR-155 induction cascade was shown to be dependent on the second messenger cyclic adenosine monophosphate (cAMP). Furthermore, we found that miR-155 directly targets the protein kinase A inhibitor alpha (PKIalpha) mRNA in its 3'UTR, indicative of a positive feedback mechanism on the cAMP pathway. Taken together, our study describes, in the context of an H. pylori infection, a direct link between Foxp3 and miR-155 in human T cells and highlights the significance of cAMP in this miR-155 induction cascade. PMID:20209161

  10. Piperine treatment suppresses Helicobacter pylori toxin entry in to gastric epithelium and minimizes β-catenin mediated oncogenesis and IL-8 secretion in vitro

    PubMed Central

    Tharmalingam, Nagendran; Park, Min; Lee, Min Ho; Woo, Hyun Jun; Kim, Hyun Woo; Yang, Ji Yeong; Rhee, Ki-Jong; Kim, Jong-Bae

    2016-01-01

    Helicobacter pylori related gastric cancer initiation has been studied widely. The objective of our present study was to evaluate the effect of a single compound piperine on H. pylori infection and its anti-inflammatory and anti-cancer effects in vitro. Cytotoxicity was tested by Ez-cytox cell viability assay kit. Effects of piperine on H. pylori toxin gene expression and IL-8 expression in mammalian cells during infection were assessed by RT-PCR. Effects of piperine on toxin entry into host cells, E-cadherin cleavage by H. pylori, and the changes in H. pylori mediated β-catenin expression and IL-8 secretion were determined by immunoblotting. Piperine treatment restrained the entry of CagA and VacA into AGS cells. Piperine administration in H. pylori infection reduced E-cadherin cleavage in stomach epithelium. In addition, H. pylori induced β-catenin up-regulation was reduced. Piperine administration impaired IL-8 secretion in H. pylori-infected gastric epithelial cells. As we reported previously piperine restrained H. pylori motility. The possible reason behind the H. pylori inhibition mechanism of piperine could be the dwindled motility, which weakened H. pylori adhesion to gastric epithelial cells. The reduced adhesion decreased the toxin entry thereby secreting less amount of IL-8. In addition, piperine treatment suppressed H. pylori protease led to reduction of E-cadherin cleavage and β-catenin expression resulting in diminished β-catenin translocation into the nucleus thus decreasing the risk of oncogenesis. To our knowledge, this is the preliminary report of piperine mediated H. pylori infection control on gastric epithelial cells in-vitro. PMID:27158376

  11. Soluble extracts from Helicobacter pylori induce dome formation in polarized intestinal epithelial monolayers in a laminin-dependent manner.

    PubMed

    Terrés, A M; Windle, H J; Ardini, E; Kelleher, D P

    2003-07-01

    Helicobacter pylori colonizes the stomach at the interface between the mucus layer and the apical pole of gastric epithelial cells. A number of secreted and shed products from the bacteria, such as proteins and lipopolysaccharide, are likely to have a role in the pathogenesis at the epithelial level. To determine the physiological response of transporting polarized epithelia to released soluble factors from the bacterium, we used the T84 cell line. Monolayers of T84 cells were exposed to soluble extracts from H. pylori. The extracts induced rapid "dome" formation as well as an immediate decrease in transepithelial electrical resistance. Domes are fluid-filled blister-like structures unique to polarized epithelia. Their formation has been linked to sodium-transporting events as well as to diminished adherence of the cells to the substrate. H. pylori-induced dome formation in T84 monolayers was exacerbated by amiloride and inhibited by ouabain. Furthermore, it was associated with changes in the expression of the laminin binding alpha 6 beta 4 integrin and the 67-kDa laminin receptor. Domes formed primarily on laminin-coated filters, rather than on fibronectin or collagen matrices, and their formation was inhibited by preincubating the bacterial extract with soluble laminin. This effect was specific to H. pylori and independent of the urease, vacA, cagA, and Lewis phenotype of the strains. These data indicate that released elements from H. pylori can alter the physiological balance and integrity of the epithelium in the absence of an underlying immune response. PMID:12819097

  12. Inter- and intra-plate deformation at North American plate boundaries

    NASA Technical Reports Server (NTRS)

    Beavan, John; Gilbert, Lewis E.; Scholz, Chris

    1992-01-01

    A geodetic network which spans the region between San Francisco and Lake Tahoe has been measured 5 times completely with triangulation in 1880, 1922, 1929, 1943, 1963. A resurvey with the Global Positioning System (GPS) in 1991 allows the formation of 1 coseismic and 4 interseismic epochs. The data from this network provide a unique opportunity to examine the temporal and spatial evolution of the strain field associated with the 1906 San Francisco earthquake in particular and with the Pacific-North American plate boundary in general. Calculations of strain rate from the network data lead to the following conclusions. (1) There is no resolvable (greater than 0.05 microradians/yr) strain in between Sutter Buttes and the Sierra Nevada. (2) Throughout the time since the 1906 earthquake, a region extending at least as far east as the westernmost Great Valley has been undergoing deformation related to Pac:Nam interaction and the associated earthquake cycle. (3) In the time and space of overlap, our results agree with those from the United States Geological Survey (USGS) trilateration data. Both data sets indicate that strain must be accumulating to the east of Vaca. (4) The San Andreas discrepancy cannot be accommodated in the Great Valley at the 1 sigma level of our results. It is possible to absorb it in that region at the 2 sigma level. (5) Strain rate is elevated in the years following the earthquake and decays slowly with time. It is possible that the rate in the Coast Ranges increases until around 1950 and then decays. With the exception of one epoch, strain rate in the Coast Ranges is consistently fault parallel, shows no sign changes, and is consistent with monotonic strain accumulation.

  13. Prospective study of Helicobacter pylori antigens and gastric noncardia cancer risk in the nutrition intervention trial cohort.

    PubMed

    Murphy, Gwen; Freedman, Neal D; Michel, Angelika; Fan, Jin-Hu; Taylor, Philip R; Pawlita, Michael; Qiao, You-Lin; Zhang, Han; Yu, Kai; Abnet, Christian C; Dawsey, Sanford M

    2015-10-15

    Helicobacter pylori (H. pylori) infection is the strongest known risk factor for gastric noncardia adenocarcinoma (GNCA). We used multiplex serology to determine whether seropositivity to 15 H. pylori proteins is associated with the subsequent development of noncardia gastric cancer in Linxian, China. We included 448 GNCA cases and 1242 controls from two time points within the Linxian General Population Nutrition Intervention Trial, Linxian. H. pylori multiplex seropositivity was defined as positivity to ≥4 of the 15 included antigens. Odds ratios (ORs) and 95% confidence intervals (CIs) were adjusted for major GNCA risk factors. In addition, we undertook a meta-analysis combining H. pylori multiplex serology data from both time points. H. pylori multiplex seropositivity was associated with a significant increase in risk of GNCA at one time point (1985; OR: 3.44, 95% CI: 1.91, 6.19) and this association remained significant following adjustment for H. pylori or CagA ELISA seropositivity (OR: 2.92, 95% CI: 1.56, 5.47). Combining data from both time points in a meta-analysis H. pylori multiplex seropositivity was associated with an increased risk of GNCA, as were six individual antigens: GroEL, HP0305, CagA, VacA, HcpC and Omp. CagM was inversely associated with risk of GNCA. We identified six individual antigens that confer an increase in risk of GNCA within this population of high H. pylori seroprevalence, as well as a single antigen that may be inversely associated with GNCA risk. We further determined that the H. pylori multiplex assay provides additional information to the conventional ELISA methods on risk of GNCA. PMID:25845708

  14. Infection by Helicobacter pylori expressing the BabA adhesin is influenced by the secretor phenotype.

    PubMed

    Azevedo, M; Eriksson, S; Mendes, N; Serpa, J; Figueiredo, C; Resende, L P; Ruvoën-Clouet, N; Haas, R; Borén, T; Le Pendu, J; David, L

    2008-07-01

    Helicobacter pylori (Hp) infects half the world's population and causes diverse gastric lesions, from gastritis to gastric cancer. Our aim was to evaluate the significance of secretor and Lewis status in infection and in vitro adherence by Hp expressing BabA adhesin. We enrolled 304 Hp-infected individuals from Northern Portugal. Gastric biopsies, blood and saliva were collected. Polymerase chain reaction (PCR) and immunofluorescence were used to detect BabA+ Hp in gastric biopsies. In vitro adherence by a BabA expressing Hp strain to gastric biopsies was performed. Secretor status was identified by Ulex, a lectin that recognizes secretor-dependent glycan structures in saliva and in gastric mucosa, and by Lewis(a/b) antibodies, and indirectly by identification of an inactivating mutation in the FUT2 gene (G428A). BabA status of infecting Hp was associated with CagA and VacAs1 (p < 0.05), intercellular localization of Hp (p < 0.01) and the presence of intestinal metaplasia (p < 0.05) and degenerative alterations (p < 0.005) in the biopsies. BabA was associated (p < 0.05) with Ulex staining of gastric biopsies and, although not significantly, to absence of homozygosity for FUT2 G428A inactivating polymorphism. In vitro Hp adherence was higher in cases wild-type or heterozygous for FUT2 G428A mutation (p < 0.0001), cases staining for Ulex (p < 0.0001) and a(-)b+ and a(-)b(-) secretor phenotypes (p < 0.001). In conclusion, BabA+ Hp infection/adhesion is secretor-dependent and associated with the severity of gastric lesions. PMID:18498114

  15. Effects of Vibration on Leg Blood Flow After Intense Exercise and Its Influence on Subsequent Exercise Performance.

    PubMed

    Sañudo, Borja; César-Castillo, Manuel; Tejero, Sergio; Cordero-Arriaza, Francisco J; Oliva-Pascual-Vaca, Ángel; Figueroa, Arturo

    2016-04-01

    Sañudo, B, César-Castillo, M, Tejero, S, Cordero-Arriaza, FJ, Oliva-Pascual-Vaca, Á, and Figueroa, A. Effects of vibration on leg blood flow after intense exercise and its influence on subsequent exercise performance. J Strength Cond Res 30(4): 1111-1117, 2016-This study aimed to determine the effects of vibration on leg blood flow after intense exercise and find out whether or not these effects can influence subsequent maximal exercise performance. Twenty-three participants performed an exercise test-to-exhaustion followed by a recovery period using six 1-minute sets of whole-body vibration (WBV; 25 Hz-4 mm) or a passive control (noWBV; 0 Hz-0 mm) in the seated position on separate days in random order. Blood flow was assessed at baseline and during each 1-minute interset rest periods post-WBV and noWBV. Thereafter, participants performed a cycle-ergometer test, and time to exhaustion and total distance covered (TDC) were recorded. During recovery, a similar trend was observed in both systolic and diastolic peak frequency dynamics in both conditions. The pulsatility index decreased (p < 0.01) from baseline during postbout 1 in both trials and during post-4 and post-5 in the WBV trial. Significant between-group differences were observed during post-4 (p ≤ 0.05) with greater decreases in pulsatility index after WBV compared with noWBV. Time to exhaustion and TDC were higher after WBV compared with noWBV. In conclusion, WBV decreased pulsatility index in the popliteal artery after maximal exercise and was effective to increase performance in a later exercise test-to-exhaustion. PMID:23820565

  16. Ureases display biological effects independent of enzymatic activity: is there a connection to diseases caused by urease-producing bacteria?

    PubMed

    Olivera-Severo, D; Wassermann, G E; Carlini, C R

    2006-07-01

    Ureases are enzymes from plants, fungi and bacteria that catalyze the hydrolysis of urea to form ammonia and carbon dioxide. While fungal and plant ureases are homo-oligomers of 90-kDa subunits, bacterial ureases are multimers of two or three subunit complexes. We showed that some isoforms of jack bean urease, canatoxin and the classical urease, bind to glycoconjugates and induce platelet aggregation. Canatoxin also promotes release of histamine from mast cells, insulin from pancreatic cells and neurotransmitters from brain synaptosomes. In vivo it induces rat paw edema and neutrophil chemotaxis. These effects are independent of ureolytic activity and require activation of eicosanoid metabolism and calcium channels. Helicobacter pylori, a Gram-negative bacterium that colonizes the human stomach mucosa, causes gastric ulcers and cancer by a mechanism that is not understood. H. pylori produces factors that damage gastric epithelial cells, such as the vacuolating cytotoxin VacA, the cytotoxin-associated protein CagA, and a urease (up to 10% of bacterial protein) that neutralizes the acidic medium permitting its survival in the stomach. H. pylori whole cells or extracts of its water-soluble proteins promote inflammation, activate neutrophils and induce the release of cytokines. In this paper we review data from the literature suggesting that H. pylori urease displays many of the biological activities observed for jack bean ureases and show that bacterial ureases have a secretagogue effect modulated by eicosanoid metabolites through lipoxygenase pathways. These findings could be relevant to the elucidation of the role of urease in the pathogenesis of the gastrointestinal disease caused by H. pylori. PMID:16862275

  17. Epidemiology of Helicobacter pylori: transmission, translocation and extragastric reservoirs.

    PubMed

    Nabwera, H M; Logan, R P

    1999-12-01

    Although H. pylori infection is endemic and despite more than 10 years of research, the mode and route of transmission remain elusive. This may, in part, be due to the inherent problems of detecting H. pylori noninvasively. The prevalence of infection varies between countries and is closely related to Growth Domestic Product. An age-cohort effect and data from longitudinal studies suggest that the incidence of infection is much higher in children than adults. In developing countries the prevalence of infection is often more than 80% in young adults, in contrast to less than 10% for similar age groups in developed countries. The observations of mosaicism (in the VacA gene) and a panmycytic population structure imply exchange of genetic material either in or outside of the host, which is supported by the increasing recognition of polyclonal infection and suggests that secondary infection occurs after primary acquisition. In addition, in children persistent primary infection may sometimes occur only after previous (repeated) exposure and/or transient colonisation of the gastric mucosa. H. pylori and other gastric Helicobacter spp are always noninvasive, but other human nongastric Helicobacter spp have sometimes been isolated from the systemic circulation in immunocompromised patients. For nonhuman hosts, intestinal Helicobacter spp are thought to translocate more frequently from the colon to the liver. Within the human host, the oral cavity is the principal extragastric reservoir, although case reports suggest that H. pylori may sometimes be found beyond the 2nd part of the duodenum. The hypothesis that H. pylori is a zoonosis or transmitted as coccoid forms by a vector (pets, houseflies) is not supported by recent research showing that H. pylori is entirely unable to support an aerobic or anaerobic metabolism and that coccoid forms are non-viable. H. pylori is primarily acquired in infancy, most probably via the oroorogastric route, from other family members or close

  18. Analysis of Genomic Diversity among Helicobacter pylori Strains Isolated from Iranian Children by Pulsed Field Gel Electrophoresis

    PubMed Central

    Falsafi, Tahereh; Sotoudeh, Nazli; Feizabadi, Mohammad-Mehdi; Mahjoub, Fatemeh

    2014-01-01

    Objective: Presence of genomic diversity among Helicobacter pylori (H. pylori) strains have been suggested by numerous investigators. Little is known about diversity of H. pylori strains isolated from Iranian children and their association with virulence of the strains. Our purpose was to assess the degree of genomic diversity among H. pylori strains isolated from Iranian-children, on the basis of vacA genotype, cagA status of the strains, sex, age as well as the pathological status of the patients. Methods: Genomic DNA from 44 unrelated H. pylori strains isolated during 1997–2009, was examined by pulse-field gel electrophoresis (PFGE). Pathological status of the patients was performed according to the modified Sydney-system and genotype/status of vacA/cagA genes was determined by PCR. PFGE was performed using XbaI restriction-endonuclease and the field inversion-gel electrophoresis system. Findings: No significant relationship was observed between the patterns of PFGE and the cagA/vacA status/genotype. Also no relationship was observed between age, sex, and pathological status of the children and the PFGE patterns of their isolates. Similar conclusion was obtained by Total Lab software. However, more relationship was observed between the strains isolated in the close period (1997–2009, 2001–2003, 2005–2007, and 2007–2009) and more difference was observed among those obtained in the distant periods (1997 and 2009). Conclusion: H. pylori strains isolated from children in Iran are extremely diverse and this diversity is not related to their virulence characteristics. Occurrence of this extreme diversity may be related to adaptation of H. pylori strains to variable living conditions during transmission between various host individuals. PMID:26019775

  19. Comparative Genomics of a Helicobacter pylori Isolate from a Chinese Yunnan Naxi Ethnic Aborigine Suggests High Genetic Divergence and Phage Insertion

    PubMed Central

    You, Yuanhai; He, Lihua; Zhang, Maojun; Zhang, Jianzhong

    2015-01-01

    Helicobacter pylori is a common pathogen correlated with several severe digestive diseases. It has been reported that isolates associated with different geographic areas, different diseases and different individuals might have variable genomic features. Here, we describe draft genomic sequences of H. pylori strains YN4-84 and YN1-91 isolated from patients with gastritis from the Naxi and Han populations of Yunnan, China, respectively. The draft sequences were compared to 45 other publically available genomes, and a total of 1059 core genes were identified. Genes involved in restriction modification systems, type four secretion system three (TFS3) and type four secretion system four (TFS4), were identified as highly divergent. Both YN4-84 and YN1-91 harbor intact cag pathogenicity island (cagPAI) and have EPIYA-A/B/D type at the carboxyl terminal of cagA. The vacA gene type is s1m2i1. Another major finding was a 32.5-kb prophage integrated in the YN4-84 genome. The prophage shares most of its genes (30/33) with Helicobacter pylori prophage KHP30. Moreover, a 1,886 bp transposable sequence (IS605) was found in the prophage. Our results imply that the Naxi ethnic minority isolate YN4-84 and Han isolate YN1-91 belong to the hspEAsia subgroup and have diverse genome structure. The genome has been extensively modified in several regions involved in horizontal DNA transfer. The important roles played by phages in the ecology and microevolution of H. pylori were further emphasized. The current data will provide valuable information regarding the H. pylori genome based on historic human migrations and population structure. PMID:25799515

  20. Molecular epidemiology and outcome of Helicobacter pylori infection in Thailand: a cultural cross roads.

    PubMed

    Vilaichone, Ratha-Korn; Mahachai, Varocha; Tumwasorn, Somying; Wu, Jeng-Yih; Graham, David Y; Yamaoka, Yoshio

    2004-10-01

    ABSTRACT Background. Thailand is at the cultural cross roads between East and South Asia. It has been suggested that this is also the region where the predominant Helicobacter pylori (H. pylori) genotype changes from East Asian to South Asian. Methods. We compared the molecular epidemiology and outcome of H. pylori infections among different ethnic groups in Thailand (Thai, Thai-Chinese and Chinese). H. pylori isolates were genotyped by polymerase chain reaction based on cagA, cag right end junction and vacA genotypes. Results. Ninety-eight isolates from 38 ethnic Thai, 20 ethnic Chinese and 40 Thai-Chinese were categorized into East Asian (45%), South/Central Asian (26%), Western (1%) or mixed type (29%). The East Asian genotype was the most common among Chinese (85%) and Thai-Chinese (55%) (p <.01 compared to ethnic Thai). The ethnicity of the mother among mixed Thai-Chinese marriages predicted the genotype of the child's H. pylori (e.g. when the mother was Chinese, 84% had East Asian type vs. 29% when the mother was Thai) (p <.001). Gastric cancer was common among ethnic Chinese with East Asian genotype (e.g. all Chinese with gastric cancer or peptic ulcer disease had East Asian genotype, whereas only 40% of Chinese with gastritis had this genotype). Conclusions. Immigration, intermarriage and the variety of H. pylori genotypes in Thailand suggest that Thailand is an ideal site for epidemiological studies attempting to relate H. pylori genotypes and host factors to outcome. Our data also support the hypothesis that the primary caretaker of the children is most likely the source of the infection. PMID:15361085

  1. J-Western Forms of Helicobacter pylori cagA Constitute a Distinct Phylogenetic Group with a Widespread Geographic Distribution

    PubMed Central

    Duncan, Stacy S.; Valk, Pieter L.; Shaffer, Carrie L.

    2012-01-01

    Chronic infection with Helicobacter pylori strains expressing the bacterial oncoprotein CagA confers an increased risk of gastric cancer. While much is known about the ancestry and molecular evolution of Western, East Asian, and Amerindian cagA sequences, relatively little is understood about a fourth group, known as “J-Western,” which has been detected mainly in strains from Okinawa, Japan. We show here that J-Western cagA sequences have a more widespread global distribution than previously recognized, occur in strains with multiple different ancestral origins (based on multilocus sequence typing [MLST] analysis), and did not arise recently. As shown by comparisons of Western and J-Western forms of CagA, there are 45 fixed or nearly fixed amino acid differences, and J-Western forms contain a unique 4-amino-acid insertion. The mean nucleotide diversity of synonymous sites (πs) is slightly lower in the J-Western group than in the Western and East Asian groups (0.066, 0.086, and 0.083, respectively), which suggests that the three groups have comparable, but not equivalent, effective population sizes. The reduced πs of the J-Western group is attributable to ancestral recombination events within the 5′ region of cagA. Population genetic analyses suggest that within the cagA region encoding EPIYA motifs, the East Asian group underwent a marked reduction in effective population size compared to the Western and J-Western groups, in association with positive selection. Finally, we show that J-Western cagA sequences are found mainly in strains producing m2 forms of the secreted VacA toxin and propose that these functionally interacting proteins coevolved to optimize the gastric colonization capacity of H. pylori. PMID:22247512

  2. Association between Helicobacter pylori virulence factors and gastroduodenal diseases in Okinawa, Japan.

    PubMed

    Matsunari, Osamu; Shiota, Seiji; Suzuki, Rumiko; Watada, Masahide; Kinjo, Nagisa; Murakami, Kazunari; Fujioka, Toshio; Kinjo, Fukunori; Yamaoka, Yoshio

    2012-03-01

    The incidence of gastric cancer in Okinawa is lowest in Japan. Some previous reports using small number of strains suggested that the high prevalence of Helicobacter pylori with Western-type cagA in Okinawa compared to other areas in Japan might contribute to the low incidence of gastric cancer. It has still not been confirmed why the prevalence of Western-type cagA strains is high in Okinawa. We examined the association between the virulence factors of H. pylori and gastroduodenal diseases in Okinawa. The genotypes of cagA and vacA of 337 H. pylori strains were determined by PCR and gene sequencing. The genealogy of these Western-type cagA strains in Okinawa was analyzed by multilocus sequence typing (MLST). Overall, 86.4% of the strains possessed cagA: 70.3% were East-Asian type and 16.0% were Western type. After adjustment by age and sex, the presence of East-Asian-type cagA/vacA s1m1 genotypes was significantly associated with gastric cancer compared to gastritis (odds ratio = 6.68, 95% confidence interval = 1.73 to 25.8). The structure of Western-type CagA in Okinawa was different from that of typical Western-type CagA found in Western countries. Intriguingly, MLST analysis revealed that the majority of Western-type cagA strains formed individual clusters but not hpEurope. Overall, low prevalence of gastric cancer in Okinawa may result from the high prevalence of non-East-Asian-type cagA strains. The origin of Western-type cagA strains in Okinawa may be different from those of Western countries. PMID:22189111

  3. A Water Resources Management Model to Evaluate Climate Change Impacts in North-Patagonia, Argentina

    NASA Astrophysics Data System (ADS)

    Bucciarelli, L. F.; Losano, F. T.; Marizza, M.; Cello, P.; Forni, L.; Young, C. A.; Girardin, L. O.; Nadal, G.; Lallana, F.; Godoy, S.; Vallejos, R.

    2014-12-01

    Most recently developed climate scenarios indicate a potential future increase in water stress in the region of Comahue, located in the North-Patagonia, Argentina. This region covers about 140,000 km2 where the Limay River and the Neuquén River converge into the Negro River, constituting the largest integrated basins in Argentina providing various uses of water resources: a) hydropower generation, contributing 15% of the national electricity market; b) fruit-horticultural products for local markets and export; c) human and industrial water supply; d) mining and oil exploitation, including Vaca Muerta, second world largest reserves of shale gas and fourth world largest reserves of shale-oil. The span of multiple jurisdictions and the convergence of various uses of water resources are a challenge for integrated understanding of economically and politically driven resource use activities on the natural system. The impacts of climate change on the system could lead to water resource conflicts between the different political actors and stakeholders. This paper presents the results of a hydrological simulation of the Limay river and Neuquén river basins using WEAP (Water Evaluation and Planning) considering the operation of artificial reservoirs located downstream at a monthly time step. This study aims to support policy makers via integrated tools for water-energy planning under climate uncertainties, and to facilitate the formulation of water policy-related actions for future water stress adaptation. The value of the integrated resource use model is that it can support local policy makers understand the implications of resource use trade-offs under a changing climate: 1) water availability to meet future growing demand for irrigated areas; 2) water supply for hydropower production; 3) increasing demand of water for mining and extraction of unconventional oil; 4) potential resource use conflicts and impacts on vulnerable populations.

  4. Helicobacter pylori inhibits dendritic cell maturation via interleukin-10-mediated activation of the signal transducer and activator of transcription 3 pathway.

    PubMed

    Rizzuti, David; Ang, Michelle; Sokollik, Christiane; Wu, Ted; Abdullah, Majd; Greenfield, Laura; Fattouh, Ramzi; Reardon, Colin; Tang, Michael; Diao, Jun; Schindler, Christian; Cattral, Mark; Jones, Nicola L

    2015-01-01

    Helicobacter pylori infects the human gastric mucosa causing a chronic infection that is the primary risk factor for gastric cancer development. Recent studies demonstrate that H. pylori promotes tolerogenic dendritic cell (DC) development indicating that this bacterium evades the host immune response. However, the signaling pathways involved in modulating DC activation during infection remain unclear. Here, we report that H. pylori infection activated the signal transducer and activator of transcription 3 (STAT3) pathway in murine bone marrow-derived DCs (BMDCs) and splenic DCs isolated ex vivo. Isogenic cagA-, cagE-, vacA- and urease-mutants exhibited levels of phosphoSTAT3 that were comparable to in the wild-type (WT) parent strain. H. pylori-infected BMDCs produced increased immunosuppressive IL-10, which activated STAT3 in an autocrine/paracrine fashion. Neutralization of IL-10 prevented H. pylori-mediated STAT3 activation in both BMDCs and splenic DCs. In addition, anti-IL-10 treatment of infected H. pylori-BMDCs was associated with increased CD86 and MHC II expression and enhanced proinflammatory IL-1β cytokine secretion. Finally, increased CD86 and MHC II expression was detected in H. pylori-infected STAT3 knockout DCs when compared to WT controls. Together, these results demonstrate that H. pylori infection induces IL-10 secretion in DCs, which activates STAT3, thereby modulating DC maturation and reducing IL-1β secretion. These findings identify a host molecular mechanism by which H. pylori can manipulate the innate immune response to potentially favor chronic infection and promote carcinogenesis. PMID:25412627

  5. Phase Variation in the Helicobacter pylori Phospholipase A Gene and Its Role in Acid Adaptation

    PubMed Central

    Tannæs, Tone; Dekker, Niek; Bukholm, Geir; Bijlsma, Jetta J. E.; Appelmelk, Ben J.

    2001-01-01

    Previously, we have shown that Helicobacter pylori can spontaneously and reversibly change its membrane lipid composition, producing variants with low or high content of lysophospholipids. The “lyso” variant contains a high percentage of lysophospholipids, adheres better to epithelial cells, and releases more proteins such as urease and VacA, compared to the “normal” variant, which has a low content of lysophospholipids. Prolonged growth of the normal variant at pH 3.5, but not under neutral conditions, leads to enrichment of lyso variant colonies, suggesting that the colony switch is relevant to acid adaptation. In this study we show that the change in membrane lipid composition is due to phase variation in the pldA gene. A change in the (C) tract length of this gene results in reversible frameshifts, translation of a full-length or truncated pldA, and the production of active or inactive outer membrane phospholipase A (OMPLA). The role of OMPLA in determining the colony morphology was confirmed by the construction of an OMPLA-negative mutant. Furthermore, variants with an active OMPLA were able to survive acidic conditions better than variants with the inactive form. This explains why the lyso variant is selected at low pH. Our studies demonstrate that phase variation in the pldA gene, resulting in an active form of OMPLA, is important for survival under acidic conditions. We also demonstrated the active OMPLA genotype in fresh isolates of H. pylori from patients referred to gastroscopy for dyspepsia. PMID:11705905

  6. Molecular epidemiology, population genetics, and pathogenic role of Helicobacter pylori

    PubMed Central

    Suzuki, Rumiko; Shiota, Seiji; Yamaoka, Yoshio

    2012-01-01

    Helicobacter pylori infection is linked to various gastroduodenal diseases; however, only approximately 20% of infected individuals develop severe diseases. Despite the high prevalence of H. pylori infection in Africa and South Asia, the incidence of gastric cancer in these areas is much lower than in other countries. Furthermore, the incidence of gastric cancer tends to decrease from north to south in East Asia. Such geographic differences in the pathology can be explained, at least in part, by the presence of different types of H. pylori virulence factors, especially cagA, vacA, and the right end of the cag pathogenicity island. The genotype of the virulence genes is also useful as a tool to track human migration utilizing the high genetic diversity and frequent recombination between different H. pylori strains. Multilocus sequence typing (MLST) analysis using 7 housekeeping genes can also help predict the history of human migrations. Population structure analysis based on MLST has revealed 7 modern population types of H. pylori, which derived from 6 ancestral populations. Interestingly, the incidence of gastric cancer is closely related to the distribution of H. pylori populations. The different incidence of gastric cancer can be partly attributed to the different genotypes of H. pylori circulating in different geographic areas. Although approaches by MLST and virulence factors are effective, these methods focus on a small number of genes and may miss information conveyed by the rest of the genome. Genome-wide analyses using DNA microarray or whole-genome sequencing technology give a broad view on the genome of H. pylori. In particular, next-generation sequencers, which can read DNA sequences in less time and at lower costs than Sanger sequencing, enabled us to efficiently investigate not only the evolution of H. pylori, but also novel virulence factors and genomic changes related to drug resistance. PMID:22197766

  7. Mesosiderites: A Chronologic and Petrologic Synthesis

    NASA Astrophysics Data System (ADS)

    Rubin, A. E.; Mittlefehldt, D. W.

    1992-07-01

    Recent petrologic, chemical, and isotopic analyses of mesosiderite clasts and whole rocks allow construction of the evolutionary history of the mesosiderite parent body (MPB) as shown in the figure. I. Initial Melting ~4.56 Ga Ago. Numerous chronologic measurements indicate that initial melting of the MPB occurred shortly after accretion, at about the same time that the eucrites and angrites formed. For example, a zircon grain from a basaltic clast in Vaca Muerta yielded a Pb-Pb age of 4.563 Ga (Ireland and Wlotzka, 1992). The 4.56-Ga event on the MPB is probably responsible for forming the monogenic basaltic clasts that compositionally resemble typical eucrites (Rubin and Mittlefehldt, 1992). II. Crustal Remelting ~4.47 Ga Ago. Internal Sm-Nd isochron ages of 4.47 Ga have been determined for gabbroic pebble 12 from Vaca Muerta and a basaltic clast from Mt. Padbury (Stewart et al., 1991). Pebble 12 is one of many clasts in mesosiderites that are highly depleted in incompatible elements and probably represent remelted crustal rocks (Rubin and Mittlefehldt, 1992). Because variation of Fe/Mn with Fe/Mg in pyroxenes from these clasts follows a trend defined by FeO reduction from a melt (Mittlefehldt, 1990), and because the reducing agents (e.g., P) were likely to have been introduced during metal-silicate mixing, the age of pebble 12 indicates that metal-silicate mixing had to have occurred >=4.47 Ga ago. III. Localized Impact Melting 4.5-3.9 Ga Ago. Localized impact melting and metamorphism were widespread on the eucrite parent body as indicated by many ages that were partially or totally reset <4.56 Ga ago. Impact melt material is common in mesosiderites of all petrologic types, and ages between 4.5-3.9 Ga are preserved. Quench-textured pebble 5 from Vaca Muerta, which is likely to have formed from a localized impact melt of material resembling a cumulate eucrite (Rubin and Jerde, 1987), has an internal isochron age of 4.42 Ga (Stewart et al., 1992). The high

  8. VIII Olimpíada Brasileira de Astronomia e Astronáutica

    NASA Astrophysics Data System (ADS)

    Garcia Canalle, João Batista; Villas da Rocha, Jaime Fernando; Wuensche de Souza, Carlos Alexandre; Pereira Ortiz, Roberto; Aguilera, Nuricel Villalonga; Padilha, Maria De Fátima Catta Preta; Pessoa Filho, José Bezerra; Soares Rodrigues, Ivette Maria

    2007-07-01

    Neste trabalho apresentamos as motivações pelas quais organizamos, em conjunto, pela primeira vez, a Olimpíada Brasileira de Astronomia incluindo a Astronáutica, em colaboração com a Agência Espacial Brasileira. Esta ampliação contribuiu para atrair ainda mais alunos, professores, escolas e patrocinadores para participarem desta Olimpíada. Em 2005 participaram da VIII Olimpíada Brasileira de Astronomia e Astronáutica (VIII OBA) 187.726 alunos distribuídos por 3.229 escolas, pertencentes a todos os estados brasileiros, incluindo o Distrito Federal. O crescimento em número de alunos participantes foi 52,4% maior do que em 2004. Em abril de 2005 organizamos, em Itapecerica da Serra, SP, um curso para os 50 alunos previamente selecionados e participantes da VII OBA e ao final selecionamos, dentre eles, uma equipe de 5 alunos, os quais representaram o Brasil na X Olimpíada Internacional de Astronomia, na China, em outubro de 2005. Ganhamos, pela primeira vez, uma medalha de ouro naquele evento. Em Agosto de 2005, organizamos a VIII Escola de Agosto para 50 alunos e respectivos professores, em Águas de Lindóia, SP, juntamente com a XXXI reunião anual da Sociedade Astronômica Brasileira (SAB). Em novembro de 2005 realizamos a I Jornada Espacial, em São José dos Campos, com 22 alunos e 22 professores selecionados dentre os participantes que melhores resultados obtiveram nas questões de Astronáutica da VIII OBA. Neste trabalho detalhamos os resultados da VIII OBA bem como as ações subseqüentes.

  9. [Not Available].

    PubMed

    Vio, Fernando; Lera, Lydia; Salinas, Judith

    2016-01-01

    Objetivo: mediante la técnica de consenso Delphi, conocer la opinión de un grupo de expertos en nutrición, educación y gastronomía para buscar consenso sobre metodologías educativas en alimentación saludable, alumnos de tercero a quinto año básico, sus familias y profesores.Métodos: con los resultados de encuestas y grupos focales realizados previamente a niños, padres y profesores, se elaboró un cuestionario que fue enviado a 51 expertos en nutrición, educación y gastronomía en una primera ronda. Los resultados fueron analizados y reenviados en una segunda ronda con las preguntas no consensuadas, obteniendo 38 respuestas.Resultados: hubo consenso en que se pueden cambiar hábitos en escuelas mediante talleres de cocina con chefs o monitores, educación activo-participativa y huertos escolares. Padres y profesores deben tener habilidades culinarias saludables para educar a los niños. Estos deben hacer uso racional del dinero en la escuela. Para ello es necesario cambiar la oferta del kiosko hacia alimentos saludables, o suprimirlo si no es saludable. Los profesores deben capacitarse con talleres de autocuidado y vida sana para educar en alimentación saludable a los niños en horarios de clase con material educativo, talleres de cocina con recetas y aprovechar horarios de desayuno y almuerzo para actividades educativas. Los padres deben participar en talleres para escoger alimentos saludables en lugares de venta y preparar menús saludables. Los niños deben aprender habilidades culinarias simples, preparando y degustando alimentos saludables. Conclusiones: estos resultados son fundamentales para diseñar materiales educativos en alimentación saludable que cambien los malos hábitos alimentarios actuales. PMID:27571651

  10. Duodenal ulcer promoting gene 1 (dupA1) is associated with A2147G clarithromycin-resistance mutation but not interleukin-8 secretion from gastric mucosa in Iraqi patients

    PubMed Central

    Hussein, N.R.; Tunjel, I.; Majed, H.S.; Yousif, S.T.; Aswad, S.I.; Assafi, M.S.

    2015-01-01

    Helicobacter pylori causes peptic ulceration and gastric adenocarcinoma. The aims were to study the influence of dupA1 positivity upon interleukin-8 (IL-8) secretion from gastric mucosa and determine the prevalence of mutations responsible for clarithromycin and fluoroquinolone resistance. DNA was extracted from 74 biopsies and the virulence factors were studied. Levels of IL-8 in gastric mucosa were measured using ELISA and the mutations responsible for clarithromycin and fluoroquinolone resistance were determined using a GenoType-HelicoDR assay. The prevalence of cagA in strains isolated from gastric ulcer (GU) and duodenal ulcer (DU) was significantly higher than those isolated from non-ulcer disease (NUD) (90% and 57.9% versus 33.3%; p 0.01). The vacA s1m1 genotype was more prevalent in patients with DU (73.7%) and GU (70%) than in those with NUD (13.3%) (p 0.01). The prevalence of dupA1 was higher in DU patients (36.8%) than those with GU (10%) and NUD (8.9%) (p 0.01). Multivariate analysis showed that a cagA+/vacA s1i1m2 virulence gene combination was independently associated with the developing peptic ulcer disease (PUD) with increased odds of developing PUD (p 0.03; OR = 2.1). We found no significant difference in the levels of IL-8 secretion in gastric mucosa infected with H. pylori dupA-negative and H. pylori dupA1-positive strains (dupA-negative: mean ± median: 28 ± 26 versus 30 ± 27.1 for dupA1; p 0.6). While 12 strains were clarithromycin resistant, only three isolates were levofloxacin resistant. A significant association was found between dupA1 genotype and A2147G clarithromycin resistance mutation (p <0.01). Further study is needed to explore the relationship between virulence factors and disease process and treatment failure. PMID:26042186

  11. Duodenal ulcer promoting gene 1 (dupA1) is associated with A2147G clarithromycin-resistance mutation but not interleukin-8 secretion from gastric mucosa in Iraqi patients.

    PubMed

    Hussein, N R; Tunjel, I; Majed, H S; Yousif, S T; Aswad, S I; Assafi, M S

    2015-07-01

    Helicobacter pylori causes peptic ulceration and gastric adenocarcinoma. The aims were to study the influence of dupA1 positivity upon interleukin-8 (IL-8) secretion from gastric mucosa and determine the prevalence of mutations responsible for clarithromycin and fluoroquinolone resistance. DNA was extracted from 74 biopsies and the virulence factors were studied. Levels of IL-8 in gastric mucosa were measured using ELISA and the mutations responsible for clarithromycin and fluoroquinolone resistance were determined using a GenoType-HelicoDR assay. The prevalence of cagA in strains isolated from gastric ulcer (GU) and duodenal ulcer (DU) was significantly higher than those isolated from non-ulcer disease (NUD) (90% and 57.9% versus 33.3%; p 0.01). The vacA s1m1 genotype was more prevalent in patients with DU (73.7%) and GU (70%) than in those with NUD (13.3%) (p 0.01). The prevalence of dupA1 was higher in DU patients (36.8%) than those with GU (10%) and NUD (8.9%) (p 0.01). Multivariate analysis showed that a cagA+/vacA s1i1m2 virulence gene combination was independently associated with the developing peptic ulcer disease (PUD) with increased odds of developing PUD (p 0.03; OR = 2.1). We found no significant difference in the levels of IL-8 secretion in gastric mucosa infected with H. pylori dupA-negative and H. pylori dupA1-positive strains (dupA-negative: mean ± median: 28 ± 26 versus 30 ± 27.1 for dupA1; p 0.6). While 12 strains were clarithromycin resistant, only three isolates were levofloxacin resistant. A significant association was found between dupA1 genotype and A2147G clarithromycin resistance mutation (p <0.01). Further study is needed to explore the relationship between virulence factors and disease process and treatment failure. PMID:26042186

  12. Deformation in the Bolivian Subandes: a reconstruction of geologic structures along two transects across the Andean Front in Southern Bolivia

    NASA Astrophysics Data System (ADS)

    Hadeen, Xennephone; Zeilinger, Gerold

    2016-04-01

    The Southern Bolivian Subandes is a highly tectonically active region in the Andes since deformation began approx. 10 Ma ago. The study area is located in the Southern Bolivian Subandes southwest of Santa Cruz. Observations were taken along two transects with each being around 100 km long. They stretch from the Subandes-Interandean boundary into the Chaco Plain. The northern transect extends from Abapó in the Chaco Plain and it continues west near Vallegrande and ends just west of Pucara near La Higuera. The southern transect initiates near Charagua in the Chaco Plain. Then it continues west through Villa Vaca Guzmán and ends around 25 km west of Monteagudo. Structural and stratigraphic data were collected along the two transects. The locations of major geologic structures such as thrust faults, anticlines and synclines were mapped. The map along with the data from the two cross sections was then used to generate a 3D model of the Subandean fold and thrust belt between Abapó and Monteagudo. The cross sections were than restored to quantify the amount of shortening that had occurred over the past 10 million years. The southern transect has undergone 65 km of shortening while 50 to 80 km of shortening have transpired along the less constrain northern transect. The estimated rate of deformation averages at 8 mm/yr. The timing of deformation may differ between the two transects. Deformation may have initiated earlier or undergone at a faster rate in the northern transect than in the southern transect. It is also possible that the decollement is shallower in the western portion of the northern transect. We observe that the east propagating anticlines verge to the west. This may be due to the anticlines being cut by exposed or blind thrust faults and then rotated counterclockwise. They rotate while piggybacking on younger thrust faults that developed and propagate to the east of the anticlines. We postulate deformation continues to propagate eastward into the Chaco

  13. Long-term periodic anthelmintic treatments are associated with increased allergen skin reactivity

    PubMed Central

    Endara, P; Vaca, M; Chico, M E; Erazo, S; Oviedo, G; Quinzo, I; Rodriguez, A; Lovato, R; Moncayo, A-L; Barreto, M L; Rodrigues, L C; Cooper, P J

    2010-01-01

    Background The low prevalence of allergic disease in the rural tropics has been attributed to the protective effects of chronic helminth infections. There is concern that treatment-based control programmes for these parasites may lead to an increase in the prevalence of allergic diseases. Objective We measured the impact of 15–17 years of anthelmintic treatment with ivermectin on the prevalence of allergen skin test reactivity and allergic symptoms in school-age children. Methods The prevalence of allergen skin test reactivity, exercise-induced bronchospasm and allergic symptoms was compared between school-age children living in communities that had received community-based treatments with ivermectin (for onchocerciasis control) for a period of 15–17 years with those living in geographically adjacent communities that had received no ivermectin. Results The prevalence of allergen skin test reactivity was double in children living in treated communities compared with those in untreated communities (16.7% vs. 8.7%, adjusted OR 2.10, 95% CI 1.50–2.94, P<0.0001), and the effect was mediated partly by a reduced prevalence of Trichuris trichiura among treated children. Ivermectin treatments were associated with an increased prevalence of recent eczema symptoms (adjusted OR 2.24, 95% CI 1.05–4.78, P=0.04) but not symptoms of asthma or rhino-conjunctivitis. The effect on eczema symptoms was not associated with reductions in geohelminth infections. Conclusion Long-term periodic treatments with ivermectin were associated with an increased prevalence of allergen skin test reactivity. There was some evidence that treatment was associated with an increased prevalence of recent eczema symptoms but not those of asthma or rhino-conjunctivitis. Cite this as: P. Endara, M. Vaca, M. E. Chico, S. Erazo, G. Oviedo, I. Quinzo, A. Rodriguez R. Lovato, A.-L. Moncayo, M. L. Barreto, L. C. Rodrigues and P. J. Cooper, Clinical & Experimental Allergy, 2010 (40) 1669–1677. PMID

  14. Paleogene and Neogene magmatism in the Valle del Cura region: New perspective on the evolution of the Pampean flat slab, San Juan province, Argentina

    NASA Astrophysics Data System (ADS)

    Litvak, Vanesa D.; Poma, Stella; Kay, Suzanne Mahlburg

    2007-09-01

    ignimbrites, the younger Cerro de las Tórtolas Formation volcanic rocks erupted at the height of contractional deformation in the Valle del Cura and to the east. The last important volcanic sequence to erupt in the Valle del Cura is the late Miocene Vacas Heladas Ignimbrite, the most isotopically enriched Tertiary magmas in the Valle del Cura that contain the highest proportion of crustal components. Subsequently volcanism ceased in the region in response to shallowing of the subduction zone.

  15. Latitudinal Discontinuity in Thermal Conditions along the Nearshore of Central-Northern Chile

    PubMed Central

    Tapia, Fabian J.; Largier, John L.; Castillo, Manuel; Wieters, Evie A.; Navarrete, Sergio A.

    2014-01-01

    Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30–32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4–10 years at 15 sites between 28–35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30–31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30–31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species

  16. Variations in water clarity and bottom albedo in Florida Bay from 1985 to 1997

    USGS Publications Warehouse

    Stumpf, R.P.; Frayer, M.L.; Durako, M.J.; Brock, J.C.

    1999-01-01

    Following extensive seagrass die-offs of the late 1980s and early 1990s, Florida Bay reportedly had significant declines in water clarity due to turbidity and algal blooms. Scant information exists on the extent of the decline, as this bay was not investigated for water quality concerns before the die-offs and limited areas were sampled after the primary die-off. We use imagery from the Advanced Very High Resolution Radiometer (AVHRR) to examine water clarity in Florida Bay for the period 1985 to 1997. The AVHRR provides data on nominal water reflectance and estimated fight attenuation, which are used here to describe turbidity conditions in the bay on a seasonal basis. In situ observations on changes in seagrass abundance within the bay, combined with the satellite data, provide additional insights into losses of seagrass. The imagery shows an extensive region to the west of Florida Bay having increased reflectance and fight attenuation in both winter and summer beginning in winter of 1988. These increases are consistent with a change from dense seagrass to sparse or negligible cover. Approximately 200 km2 of these offshore seagrasses may have been lost during the primary die-off (1988 through 1991), significantly more than in the bay. The imagery shows the distribution and timing of increased turbidity that followed the die-offs in the northwestern regions of the bay, exemplified in Rankin Lake and Johnson Key Basin, and indicates that about 200 km2 of dense seagrass may have been lost or severely degraded within the bay from the start of the die-off. The decline in water clarity has continued in the northwestern bay since 1991. The area west of the Everglades National Park boundaries has shown decreases in both winter turbidity and summer reflectances, suggestive of partial seagrass recovery. Areas of low reflectance associated with a major Syringodium filiforme seagrass meadow north of Marathon (Vaca Key, in the Florida Keys) appear to have expanded westward

  17. Anisotropy of Magnetic Susceptibility: a petrofrabric tool for understanding mechanisms of fold and thrust belt evolution. Application in Malargüe FTB, Argentina

    NASA Astrophysics Data System (ADS)

    Branellec, Matthieu; Callot, Jean Paul; Aubourg, Charles; Nivière, Bertrand; Ringenbach, Jean Claude

    2013-04-01

    In fold and thrust belts (FTB), sedimentary beds are folded and faulted but rocks do not always show evidence of strong internal deformation. Nevertheless, several studies have demonstrated that a weak internal deformation (layer parallel shortening) can be recorded at the matrix scale before any macroscopic deformation. The Anisotropy of Magnetic susceptibility (AMS) provides information about the preferred orientation of billions of magnetic minerals. It enables the definition of a magnetic fabric, which may be visualized as an ellipsoid with principal axes K1 ≥ K2 ≥ K3. Basic elements of a magnetic fabric are the magnetic foliation (K1-K2 plane) and the magnetic lineation (K1 axe), when they are statistically defined. Both are related to strain-controlled petrofrabric. The Neuquén Basin is a wide intracratonic sag basin with complex and polyphased/diachronic evolution. The Pacific subduction and south Atlantic opening were the mechanisms controlling the large scale geodynamic framework. By late Triassic times, continental scale extension initiated fault-related narrow rift depocenters which later evolved toward a sag basin from middle Jurassic to upper Cretaceous. At that time, the basin started to record the compressive stress regime from the Pacific subduction. Three pulses of compressive deformation (Cretaceous, Paleogene and Miocene) are recorded in this retro-arc foreland setting. Approximately 300 samples have been collected from 30 sites in terrigenous rocks located along three cross sections from foothills to uplifted foreland area in Malargüe FTB. We mainly sample Kimmeridgian red beds of the Tordillo formation, Tithonian shales from the Vaca Muerta Fm, and late cretaceous red beds of the Neuquén Group. AMS fabrics are used as a proxy to measure accumulated microscopic finite strain and compares it with mesoscale (fractures) and macroscale structures (faults, folds…). This multi-scaled approach helps in defining a kinematic scenario for Malarg

  18. Method for cutting steam heat losses during cyclic steam injection of wells. Second quarterly report

    SciTech Connect

    Not Available

    1994-08-01

    The Midway-Sunset Field (CA) is the largest Heavy Oil field in California and steam injection methods have been successfully used for more than 30 years to produce the Heavy Oil from many of its unconsolidated sand reservoirs. In partnership with another DOE/ERIP grantee, our Company has acquired an 80 ac. lease in the SE part of this field, in order to demonstrate our respective technologies in the Monarch sand, of Miocene Age, which is one of the reservoirs targeted by the DOE Class 3 Oil Program. This reservoir contains a 13 API oil, which has a much higher market value, as a Refinery Feedstock, than the 5 to 8 API Vaca Tar, used only as road paving material. This makes it easier to justify the required investment in a vertical well equipped with two horizontal drainholes. The economic viability of such a project is likely to be enhanced if Congress approves the export to Japan of a portion of the 27 API (1% Sulfur) AK North Slope oil, which currently is landed in California in preference to lighter and sweeter Far East imported crudes. This is a major cause of the depressed prices for California Heavy Oil in local refineries, which have reduced the economic viability of all EOR methods, including steam injection, in California. Two proposals, for a Near-Term (3 y.) and for a Mid-Term (6 y.) project respectively, were jointly submitted to the DOE for Field Demonstration of the Partners` new technologies under the DOE Class 3 Oil Program. The previous design of a special casing joint for the Oxnard field well was reviewed and adapted to the use of existing Downhole Hardware components from three suppliers, instead of one. The cost of drilling and completion of a well equipped with two horizontal drainholes was re-evaluated for the conditions prevailing in the Midway Sunset field, which are more favorable than in the Oxnard field, leading to considerable reductions in drilling rig time and cost.

  19. Helicobacter pylori-Mediated Protection from Allergy Is Associated with IL-10-Secreting Peripheral Blood Regulatory T Cells.

    PubMed

    Hussain, Khiyam; Letley, Darren P; Greenaway, A Borgel; Kenefeck, Rupert; Winter, Jody A; Tomlinson, William; Rhead, Joanne; Staples, Emily; Kaneko, Kazuyo; Atherton, John C; Robinson, Karen

    2016-01-01

    Helicobacter pylori infections are usually established in early childhood and continuously stimulate immunity, including T-helper 1 (Th1), Th17, and regulatory T-cell (Treg) responses, throughout life. Although known to be the major cause of peptic ulcer disease and gastric cancer, disease occurs in a minority of those who are infected. Recently, there has been much interest in beneficial effects arising from infection with this pathogen. Published data robustly show that the infection is protective against asthma in mouse models. Epidemiological studies show that H. pylori is inversely associated with human allergy and asthma, but there is a paucity of mechanistic data to explain this. Since Th1 and Treg responses are reported to protect against allergic responses, we investigated if there were links between the human systemic Th1 and Treg response to H. pylori and allergen-specific IgE levels. The human cytokine and T-cell responses were examined using peripheral blood mononuclear cells (PBMCs) from 49 infected and 58 uninfected adult patients. Concentrations of total and allergen-specific plasma IgE were determined by ELISA and ImmunoCAP assays. These responses were analyzed according to major virulence factor genotypes of the patients' colonizing H. pylori strains. An in vitro assay was employed, using PBMCs from infected and uninfected donors, to determine the role of Treg cytokines in the suppression of IgE. Significantly higher frequencies of IL-10-secreting CD4(+)CD25(hi) Tregs, but not H. pylori-specific Th1 cells, were present in the peripheral blood of infected patients. Total and allergen-specific IgE concentrations were lower when there was a strong Treg response, and blocking IL-10 in vitro dramatically restored IgE responses. IgE concentrations were also significantly lower when patients were infected with CagA(+) strains or those expressing the more active i1 form of VacA. The systemic IL-10(+) Treg response is therefore likely to play a role in H

  20. Relative breed contributions to neutral genetic diversity of a comprehensive representation of Iberian native cattle.

    PubMed

    Cañón, J; García, D; Delgado, J V; Dunner, S; Telo da Gama, L; Landi, V; Martín-Burriel, I; Martínez, A; Penedo, C; Rodellar, C; Zaragoza, P; Ginja, C

    2011-08-01

    This study is aimed at establishing priorities for the optimal conservation of genetic diversity among a comprehensive group of 40 cattle breeds from the Iberian Peninsula. Different sets of breed contributions to diversity were obtained with several methods that differ in the relative weight attributed to the within- and between-breed components of the genetic variation. The contributions to the Weitzman diversity and the expected heterozygosity (He) account for between- and within-breed variation only, respectively. Contributions to the core set obtained for several kinship matrices, incorporate both sources of variation, as well as the combined contributions of Ollivier and Foulley and those of Caballero and Toro. In general, breeds that ranked high in the different core set applications also ranked high in the contribution to the global He, for example, Sayaguesa, Retinta, Monchina, Berrenda en Colorado or Marismeña. As expected, the Weitzman method prioritised breeds with low contributions to the He, like Mallorquina, Menorquina, Berrenda en Negro, Mostrenca, Vaca Palmera or Mirandesa, all showing highly negative contributions to He - that is, their removal would significantly increase the average He. Weighing the within- and between-breed components with the FST produced a balanced set of contributions in which all the breeds ranking high in both approaches show up. Unlike the other methods, the contributions to the diversity proposed by Caballero and Toro prioritised a good number of Portuguese breeds (Arouquesa, Barrosã, Mertolenga and Preta ranking highest), but this might be caused by a sample size effect. Only Sayaguesa ranked high in all the methods tested. Considerations with regard to the conservation scheme should be made before adopting any of these approaches: in situ v. cryoconservation, selection and adaptation within the breeds v. crossbreeding or the creation of synthetic breeds. There is no general consensus with regard to balancing within

  1. Latitudinal discontinuity in thermal conditions along the nearshore of central-northern Chile.

    PubMed

    Tapia, Fabian J; Largier, John L; Castillo, Manuel; Wieters, Evie A; Navarrete, Sergio A

    2014-01-01

    Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30-32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4-10 years at 15 sites between 28-35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30-31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30-31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species

  2. Coastal Upwelling off Chile: Ocean Productivity and Surface Sediments

    NASA Astrophysics Data System (ADS)

    Hebbeln, D.; Lamy, F.

    2002-12-01

    The coastal upwelling system of the Peru-Chile Current belongs to the most productive regions in the world oceans. In spite of this fact only very little is known about the sediment distribution in its southern part off the coast of Chile. To increase the knowledge about this region a multi-parameter study of the surface sediment distribution at over 100 sampling sites along the Chilean continental slope between 23°S and 45°S has been carried out. Detailed analyses of sedimentary data (TOC, carbonate, and biogenic opal contents, delta 15N) reveal a close relation to environmental conditions in the region. Coastal upwelling along the Chilean coast, centered around main upwelling centers such as off Antofagasta (23°S), off Lengua de Vaca (30°S), off Valparaiso (33°S), and off Concepci¢n (35-38°S), sustains the high productivity observed in satellite pigment data and in sediment data. However, the highest pigment concentrations are found south of 40°S where prevailing onshore winds of the Southern Westerlies generally prevent coastal upwelling. There, also highest estimated accumulation rates of organic carbon and biogenic opal at the sea floor are found. Thus, the general pattern of a southward increase of surface water productivity known from satellite data is closely reflected in the organic carbon, biogenic opal and ?15N data, although the observation of highest productivity south of the upwelling area is surprising. Probably, this high productivity in the south can be attributed to the advection of (macro-) nutrients by the Antarctic Circumpolar Current, supplying so-called high nutrient-low chlorophyll (HNLC) waters to the Chilean margin. Impinging on the Chilean margin these waters can take up micronutrients such as iron from the strong riverine input and from benthic exchange processes. The combination of macro- and micro-nutrients in this area most likely results in the high productivity of the area between 40°S and 45°S. From there these fertile

  3. Are sills really elastic hydraulic fractures?

    NASA Astrophysics Data System (ADS)

    Spacapan, Juán B.; Galland, Olivier; Leanza, Héctor A.; Planke, Sverre

    2015-04-01

    Seismic reflection data and field observations have over the past few decades revealed the presence of voluminous igneous sill complexes in sedimentary basins worldwide. The implications of sill emplacement in sedimentary basins are numerous: they trigger maturation of organic-rich formations, they produce large quantities of greenhouse gases that trigger dramatic climate change and mass extinctions, and they produce small- and large-scale structures that affect fluid flow. Therefore, a proper understanding of their emplacement mechanism is essential. Most models of sill and laccolith emplacement account for purely elastic host rock, and their propagation mechanism is dominantly assumed to be according to the Linear Elastic Fracture Mechanics (LEFM) theory. Recent field and seismic observations, however, demonstrated that part, if not all, sill- and laccolith-induced deformation is accommodated by inelastic deformation, strongly questioning the relevance of the LEFM theory applied for igneous intrusions. In this contribution, we present detailed structural observations from spectacularly well-exposed sills in the northern Neuquén Basin, Argentina. We studied a 50-m outcrop that exhibits very clearly three sills of different sizes, the shapes of their tips, and the associated structures in their sedimentary host rock, i.e. the calcareous pelites of the organic-rich Vaca Muerta Fm. This formation is adequate to map the structures at the outcrop scale, as it consists in fine layers of mudstone inter-bedded with weak shale, such that it is possible to map each layer along the entire outcrop. Detailed structural mapping evidence that the sedimentary layers have not been opened, i.e. pushed away by the emplacement of the sills, as expected from the LEFM theory. Indeed, some of the sedimentary layers are not present at the location of the sills, but they appear duplicated several times ahead of the tips of the three observed sills; the relative movements between the

  4. Helicobacter pylori-Mediated Protection from Allergy Is Associated with IL-10-Secreting Peripheral Blood Regulatory T Cells

    PubMed Central

    Hussain, Khiyam; Letley, Darren P.; Greenaway, A. Borgel; Kenefeck, Rupert; Winter, Jody A.; Tomlinson, William; Rhead, Joanne; Staples, Emily; Kaneko, Kazuyo; Atherton, John C.; Robinson, Karen

    2016-01-01

    Helicobacter pylori infections are usually established in early childhood and continuously stimulate immunity, including T-helper 1 (Th1), Th17, and regulatory T-cell (Treg) responses, throughout life. Although known to be the major cause of peptic ulcer disease and gastric cancer, disease occurs in a minority of those who are infected. Recently, there has been much interest in beneficial effects arising from infection with this pathogen. Published data robustly show that the infection is protective against asthma in mouse models. Epidemiological studies show that H. pylori is inversely associated with human allergy and asthma, but there is a paucity of mechanistic data to explain this. Since Th1 and Treg responses are reported to protect against allergic responses, we investigated if there were links between the human systemic Th1 and Treg response to H. pylori and allergen-specific IgE levels. The human cytokine and T-cell responses were examined using peripheral blood mononuclear cells (PBMCs) from 49 infected and 58 uninfected adult patients. Concentrations of total and allergen-specific plasma IgE were determined by ELISA and ImmunoCAP assays. These responses were analyzed according to major virulence factor genotypes of the patients’ colonizing H. pylori strains. An in vitro assay was employed, using PBMCs from infected and uninfected donors, to determine the role of Treg cytokines in the suppression of IgE. Significantly higher frequencies of IL-10-secreting CD4+CD25hi Tregs, but not H. pylori-specific Th1 cells, were present in the peripheral blood of infected patients. Total and allergen-specific IgE concentrations were lower when there was a strong Treg response, and blocking IL-10 in vitro dramatically restored IgE responses. IgE concentrations were also significantly lower when patients were infected with CagA+ strains or those expressing the more active i1 form of VacA. The systemic IL-10+ Treg response is therefore likely to play a role in H. pylori

  5. In vitro effect of amoxicillin and clarithromycin on the 3’ region of cagA gene in Helicobacter pylori isolates

    PubMed Central

    Bustamante-Rengifo, Javier Andrés; Matta, Andrés Januer; Pazos, Alvaro; Bravo, Luis Eduardo

    2013-01-01

    AIM: To evaluate the in vitro effect of amoxicillin and clarithromycin on the cag pathogenicity island (cag PAI). METHODS: One hundred and forty-nine clinical isolates of Helicobacter pylori (H. pylori) cultured from gastric biopsies from 206 Colombian patients with dyspeptic symptoms from a high-risk area for gastric cancer were included as study material. Antimicrobial susceptibility was determined by the agar dilution method. Resistant isolates at baseline and in amoxicillin and clarithromycin serial dilutions were subjected to genotyping (cagA, vacA alleles s and m), Glu-Pro-Ile-Tyr-Ala (EPIYA) polymerase chain reaction and random amplified polymorphic DNA (RAPD). Images of the RAPD amplicons were analyzed by Gel-Pro Analyzer 4.5 program. Cluster analyses was done using SPSS 15.0 statistical package, where each of the fingerprint bands were denoted as variables. Dendrograms were designed by following Ward’s clustering method and the estimation of distances between each pair of H. pylori isolates was calculated with the squared Euclidean distance. RESULTS: Resistance rates were 4% for amoxicillin and 2.7% for clarithromycin with 2% double resistances. Genotyping evidenced a high prevalence of the genotype cagA-positive/vacA s1m1. The 3’ region of cagA gene was successfully amplified in 92.3% (12/13) of the baseline resistant isolates and in 60% (36/60) of the resistant isolates growing in antibiotic dilutions. Upon observing the distribution of the number of EPIYA repetitions in each dilution with respect to baseline isolates, it was found that in 61.5% (8/13) of the baseline isolates, a change in the number of EPIYA repetitions lowered antibiotic pressure. The gain and loss of EPIYA motifs resulted in a diversity of H. pylori subclones after bacterial adjustment to changing conditions product of antibiotic pressure. RAPD PCR evidenced the close clonal relationship between baseline isolates and isolates growing in antibiotic dilutions. CONCLUSION: Antibiotic

  6. Moléculas orgánicas obtenidas en simulaciones experimentales del medio interestelar.

    NASA Astrophysics Data System (ADS)

    Muñoz-Caro, Guillermo Manuel

    Las nubes moleculares son regiones de formación de estrellas, con temperaturas cinéticas entre 10-50 K y densidades de 103-106 átomos cm-3. Su materia está formada por gas y polvo interestelar. Estas partículas de polvo están cubiertas por una fina capa de hielo, de unos 0.01 μm, que contiene H2O y a menudo CO, CO2, CH3OH y NH3. El hielo es presumiblemente irradiado por fotones ultravioleta y rayos cósmicos en las zonas poco profundas de las nubes moleculares y las regiones circunestelares. En un sistema de vacío, P ˜ 10-7 mbar, simulamos la deposición de hielo a partir de 10 K y la irradiación ultravioleta por medio de una lámpara de descarga de hidrógeno activada con microondas. La evolución del hielo se observa por medio de un espectrómetro infrarrojo. De este modo es posible determinar la composición del hielo observado en el medio interestelar y predecir la presencia de moléculas aún no detectadas en el espacio, que han sido producto del procesamiento del hielo en nuestros experimentos. También es posible calentar el sistema hasta temperatura ambiente para sublimar el hielo depositado. Cuando el hielo ha sido previamente irradiado, se observa un residuo compuesto por moléculas orgánicas complejas, algunas prebióticas, como varios ácidos carboxílicos, aminas, amidas, ésteres y en menor proporción moléculas heterocíclicas y aminoácidos. Algunas de estas moléculas podrían detectarse en estado gaseoso por medio de observaciones milimétricas y de radio. También podrían estar presentes en el polvo cometario, cuyo análisis químico está planeado por las misiones Stardust y Rosetta. Mientras tanto, nuestro grupo está llevando a cabo el análisis de partículas de polvo interplanetario (IDPs), algunas de las cuales pueden ser de origen cometario. Al igual que ocurre con los productos obtenidos por irradiación del hielo en nuestros experimentos, algunas IDPs son ricas en material orgánico que contiene oxígeno.

  7. [In Process Citation].

    PubMed

    González-Fandos, Elena; Simón, Ana

    2016-01-01

    Se ha estudiado el efecto de la cocción en agua sobre la capacidad antioxidante y calidad sensorial de coliflor que previamente ha sido cortada, envasada en atmósfera modificada (5,7-2,3% de CO 2 y 17,6-19,7% de O 2 ) y almacenada a 5 oC durante 13 días, comparándola con la coliflor recién recolectada. Se ha observado un aumento de ácido ascórbico (18%), polifenoles (74%) y actividad antioxidante (21%) en la coliflor almacenada cruda. La cocción produjo pérdidas de estos compuestos por lixiviación, que fueron mayores en la coliflor almacenada respecto a la inicial (19% y 13% res- pectivamente para el ácido ascórbico y 31% y 28% respectivamente para los polifenoles. Sin embargo, no se observaron variaciones en la actividad antioxidante de la coliflor inicial cocida respecto a la coliflor inicial fresca, mientras que en la coliflor almacenada dicha variación fue del 16%. Como resultado, la actividad antioxidante de la coliflor almacenada y cocida ha resultado similar a la de la coliflor inicial fresca. El almacenamiento produjo pequeños cambios en color (un aumento del parámetro b* de 19 a 20,9) y de la textura (un aumento de la fuerza de cizallamiento de 1948 N a 2375 N). La valoración sensorial del color y sabor de la coliflor cocida almacenada fue inferior al de la coliflor cocida inicial, pero dentro de niveles aceptables. El aumento de la dureza en la coliflor fresca almacenada no fue detectado por el panel de catadores en la coliflor cocida. Se observó una ligera incidencia de mohos en la coliflor almacenada 13 días, por lo que se recomienda realizar un tratamiento de lavado. PMID:27238800

  8. Espectroscopia de candidatos a remanescentes de aglomerados abertos

    NASA Astrophysics Data System (ADS)

    Pavani, D. B.; Bica, E.; Ahumada, A. V.; Clariá, J. J.

    2003-08-01

    A pesquisa sobre remanescentes de aglomerados abertos tem despertado grande interesse. Seguindo esta tendência encontramos estudos teóricos e observacionais. Os primeiros baseiam-se em simulações numéricas buscando determinar fração de binárias e distâncias galatocêntricas, tempo de vida e conteúdo estelar. Estes estão relacionados à função inicial de massa e densidade de estrelas, ou seja, se ricos ou pobremente povoados, compactos ou esparsos. No caso observacional procuram-se identificar os remanescentes considerando-se que trazem estas assinaturas de seus percursores. No presente estudo empregamos espectroscopia para analisar oito concentrações pobremente povoadas, previamente classificadas como aglomerados abertos, sendo sete compactas e uma esparsa. As observações foram obtidas através do telescópio de 2,15 m do CASLEO em San Juan, Argentina, em turnos entre 2001 e 2003. Utilizamos uma câmara CCD contendo um chip Tektronics de 1024X1024 pixeis aliado a um espectrógrafo REOSC. O domínio espectral vai de 3700 a 7000 Å. As reduções foram realizadas no Observatório Astronômico de Córdoba (Argentina) usando pacotes IRAF padrões. Determinamos idades, avermelhamentos e tipos espectrais através de comparações com biblioteca de estrelas e de aglomerados. Em alguns casos nossos espectros estavam dominados por estrelas individuais às quais determinamos seus tipos espectrais. Aos oito objetos adicionamos mais cinco da literatura recente analisados via espectro ou diagrama cor-magnitude. O histograma resultante contém idades típicas entre 0.5 e 3 Ganos. Considerando que predominantemente estes objetos encontram-se na vizinhança solar e, portanto, não cruzaram muitas vezes o plano Galático esperamos que a diferença no tempo necessário para dissolução destes prováveis remanescentes seja em função de diferentes massas iniciais.

  9. Pneumatocele selar a tensión: Reporte de un caso y revisión de la literatura

    PubMed Central

    Campero, Álvaro; Ajler, Pablo; Goldschmidt, Ezequiel; Bendersky, Damián; Campero, Abraham

    2012-01-01

    Introducción: El neumoencéfalo a tensión luego de la cirugía transesfenoidal es poco común. En la literatura existen pocos casos reportados en los cuales el aire se encuentra localizado exclusivamente en las regiones selar y supraselar, constituyendo un pneumatocele selar. En este artículo se describe un caso inusual de pneumatocele selar a tensión de presentación tardía. Descripción del caso: Una mujer de 57 años consultó por hemianopsia bitemporal. Previamente, ya se le había realizado una cirugía transnasal por un adenoma hipofisario y se le había colocado una derivación lumbo-peritoneal por la presencia de una fístula de líquido cefalorraquídeo. Además, se le había realizado una resección transcraneal de un componente intracavernoso del tumor y radiocirugía debido a la agresividad del mismo. Se llevó a cabo una resonancia magnética que demostró un pneumatocele selar y supraselar. Intervención: Se realizó un abordaje transciliar. La región selar estaba encapsulada por tejido cicatrizal debido a los procedimientos previos. Se abrió la cicatriz y el aire fue evacuado. Posteriormente, el piso selar fue cerrado con grasa y cola de fibrina. Despuós del procedimiento, su campo visual retornó a la normalidad. Un año después de su última cirugía, continua asintomática. Conclusión: El pneumatocele selar y supraselar a tensión es un hallazgo extremadamente raro luego de una cirugía transesfenoidal. Su manifestaciónw clínica sería la alteración visual debida a la compresión inferior de la vía óptica. El pneumatocele selar a tensión debe ser evacuado en un corto plazo. PMID:23596554

  10. Abundâncias químicas de estrelas T Tauri fracas

    NASA Astrophysics Data System (ADS)

    Rojas, G. A.; Gregorio-Hetem, J.

    2003-08-01

    Apresentamos resultados do estudo de 44 estrelas pré-seqüência principal, para as quais buscamos realizar uma classificação espectroscópica e determinar parâmetros estelares e abundâncias químicas. A amostra foi escolhida da seguinte maneira : 21 objetos selecionados a partir de catálogos de objetos jovens, como o Pico dos Dias Survey e o Herbig Bell Catalogue, e 23 objetos selecionados a partir de contrapartidas ópticas de fontes de raios X detectadas pelo satélite ROSAT. Dentre 24 objetos previamente classificados como estrelas T Tauri Fracas, apenas 7 revelaram ser realmente pertencentes à essa classe, sendo os demais objetos T Tauri Clássicas ou estrelas evoluídas da pré-seqüência principal. Esse resultado demonstra que o critério mais utilizado para distinguir as T Tauri Clássicas das T Tauri Fracas, baseado na largura equivelente da emissão Ha, não é suficiente para determinar o estágio evolutivo desses objetos. Para o cálculo de parâmetros estelares e abundâncias, foram escolhidas as estrelas que apresentam características ideais para esse tipo de estudo, como ausência de velamento, baixa velocidade de rotação e espectros com razão sinal-ruído adequada. Os parâmetros estelares como temperatura efetiva e gravidade foram determinados através do equilíbrio de excitação e ionização das linhas de Ferro, e as abundâncias químicas foram calculadas utilizando o método de síntese espectral. Serão apresentados os parâmetros estelares e as abundâncias de Lítio para toda a amostra, e abundâncias de vários elementos quimicos para 7 estrelas estudadas em maior detalhe

  11. [In Process Citation].

    PubMed

    Villa Jiménez, Ivonne; Aguilar Cordero, María José; Guisado Barrilao, Rafael; Naranjo Orellana, José; Guerrero Almeida, Laura

    2016-01-01

    Este estudio analiza la respuesta ventilatoria en 46 niños varones (8,28 ± 1 años) durante una prueba máxima incremental en cicloergómetro y las concentraciones de lactato sanguíneo al final de la prueba. El incremento fue de 10 vatios cada minuto y se inició a 25 vatios. Durante la prueba el aire espirado se recolectó a través de una mascarilla facial y se analizó respiración a respiración. El segundo umbral ventilatorio (VT 2 ) se determinó según los métodos de intercambio de gases. Todos los niños alcanzaron una potencia máxima (P máx ) de 82,4 ± 1,6 W y un consumo pico de oxígeno (VO 2 ) de 44,69 ± 3,01 ml/kg/min. El VT 2 estaba en el 86,5% del VO 2pico . El lactato sanguíneo al final de la prueba fue de 9,65 ± 1,58 mM/l. Las concentraciones de lactato sanguíneo son mucho mayores que las registradas en la mayoría de los estudios previos y no parecen ser diferentes a las observadas en deportistas bien entrenados al final de una prueba similar. La ecuación que obtuvimos de la relación entre producción de dióxido de carbono (VCO 2 ) y ventilación (VE) fue lineal (y = 0,0324x - 0,008; R 2 = 0,999). En comparación con adultos evaluados previamente en nuestro laboratorio (y = 0,0347x + 0,1452; R 2 = 0,9854) fueron prácticamente idénticas. Esto puede ser un argumento válido para considerar que la capacidad de eliminar CO 2 en niños es tan alta como la de los adultos. PMID:27238813

  12. Planificación Neuroquirúrgica con Software Osirix

    PubMed Central

    Jaimovich, Sebastián Gastón; Guevara, Martin; Pampin, Sergio; Jaimovich, Roberto; Gardella, Javier Luis

    2014-01-01

    Introducción: La individualidad anatómica es clave para reducir el trauma quirúrgico y obtener un mejor resultado. Actualmente, el avance en las neuroimágenes ha permitido objetivar esa individualidad anatómica, permitiendo planificar la intervención quirúrgica. Con este objetivo, presentamos nuestra experiencia con el software Osirix. Descripción de la técnica: Se presentan 3 casos ejemplificadores de 40 realizados. Caso 1: Paciente con meningioma de la convexidad parasagital izquierda en área premotora; Caso 2: Paciente con macroadenoma hipofisario, operada previamente por vía transeptoesfenoidal en otra institución con una resección parcial; Caso 3: Paciente con lesiones en pedúnculo cerebeloso medio bilateral. Se realizó la planificación prequirúrgica con el software OsiriX, fusionando y reconstruyendo en 3D las imágenes de TC e IRM, para analizar relaciones anatómicas, medir distancias, coordenadas y trayectorias, entre otras funciones. Discusión: El software OsiriX de acceso libre y gratuito permite al cirujano, mediante la fusión y reconstrucción en 3D de imágenes, analizar la anatomía individual del paciente y planificar de forma rápida, simple, segura y económica cirugías de alta complejidad. En el Caso 1 se pudo analizar las relaciones del tumor con las estructuras adyacentes para minimizar el abordaje. En el Caso 2 permitió comprender la anatomía post-operatoria previa del paciente, para determinar la trayectoria del abordaje transnasal endoscópico y la necesidad de ampliar su exposición, logrando la resección tumoral completa. En el Caso 3 permitió obtener las coordenadas estereotáxicas y trayectoria de una lesión sin representación tomográfica. Conclusión: En casos de no contar con costosos sistemas de neuronavegación o estereotáxia el software OsiriX es una alternativa a la hora de planificar la cirugía, con el objetivo de disminuir el trauma y la morbilidad operatoria. PMID:25165617

  13. Potential effect of chronic Helicobacter pylori infection on glucose metabolism of Mongolian gerbils

    PubMed Central

    Yang, Zhen; Li, Wei; He, Cong; Xie, Chuan; Zhu, Yin; Lu, Nong-Hua

    2015-01-01

    AIM: To assess the effect of Helicobacter pylori (H. pylori) infection on metabolic parameters in Mongolian gerbils. METHODS: A total of 40 male, 5- to 8-wk-old, specific-pathogen-free Mongolian gerbils (30-50 g) were randomly allocated into two groups: a control group (n = 20) and an H. pylori group (n = 20). After a two-week acclimation period, the control group was administered Brucella broth and the H. pylori group was challenged intra-gastrically five times every other day with approximately 109/CFU H. pylori ATCC43504 (CagA+, VacA+). Each group was then divided into two subgroups, which were sacrificed at either 6 or 12 mo. The control and H. pylori subgroups each contained 10 Mongolian gerbils. Body weight, abdominal circumference, and body length were measured, and body mass index (BMI) and Lee’s index were calculated. Biochemical assays were used to detect serum indexes, including glucose, glycated hemoglobin (GHb), glycated hemoglobin A1c (HbA1c), triacylglycerol, and total cholesterol, using an automatic biochemistry analyzer. Inflammatory cytokines, including interleukin (IL)-1β, IL-2, IL-4, IL-10, IL-12, tumor necrosis factor-α (TNF-α) and interferon (IFN)-γ, were assayed using ELISA. The expression of insulin and insulin-like growth factor 1 (IGF-1) was detected by immunohistochemistry, and islet apoptosis was measured using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. RESULTS: At each time point, body weight, abdominal circumference, BMI, and Lee’s index were increased after H. pylori infection. However, these differences were not significant. H. pylori infection significantly increased the GHb (5.45 ± 0.53 vs 4.98 ± 0.22, P < 0.05) and HbA1c (4.91 ± 0.61 vs 4.61 ± 0.15, P < 0.05) levels at 12 mo. We observed no significant differences in serum biochemical indexes, including fasting blood glucose, triacylglycerol and total cholesterol, at 6 or 12 mo after infection. H. pylori infection

  14. Geochemistry and oxygen isotope composition of main-group pallasites and olivine-rich clasts in mesosiderites: Implications for the "Great Dunite Shortage" and HED-mesosiderite connection

    NASA Astrophysics Data System (ADS)

    Greenwood, Richard C.; Barrat, Jean-Alix; Scott, Edward R. D.; Haack, Henning; Buchanan, Paul C.; Franchi, Ian A.; Yamaguchi, Akira; Johnson, Diane; Bevan, Alex W. R.; Burbine, Thomas H.

    2015-11-01

    Evidence from iron meteorites indicates that a large number of differentiated planetesimals formed early in Solar System history. These bodies should have had well-developed olivine-rich mantles and consequentially such materials ought to be abundant both as asteroids and meteorites, which they are not. To investigate this "Great Dunite Shortage" we have undertaken a geochemical and oxygen isotope study of main-group pallasites and dunitic rocks from mesosiderites. Oxygen isotope analysis of 24 main-group pallasites (103 replicates) yielded a mean Δ17O value of -0.187 ± 0.016‰ (2σ), which is fully resolved from the HED Δ17O value of -0.246 ± 0.014 (2σ) obtained in our earlier study and demonstrates that both groups represent distinct populations and were derived from separate parent bodies. Our results show no evidence for Δ17O bimodality within the main-group pallasites, as suggested by a number of previous studies. Olivine-rich materials from the Vaca Muerta, Mount Padbury and Lamont mesosiderites, and from two related dunites (NWA 2968 and NWA 3329), have Δ17O values within error of the mesosiderite average. This indicates that these olivine-rich materials are co-genetic with other mesosiderite clasts and are not fragments from an isotopically distinct pallasite-like impactor. Despite its extreme lithologic diversity the mesosiderite parent body was essentially homogeneous with respect to Δ17O, a feature best explained by an early phase of large-scale melting (magma ocean), followed by prolonged igneous differentiation. Based on the results of magma ocean modeling studies, we infer that Mg-rich olivines in mesosiderites formed as cumulates in high-level chambers and do not represent samples of the underlying mantle. By analogy, recently documented Mg-rich olivines in howardites may have a similar origin. Although the Dawn mission did not detect mesosiderite-like material on Vesta, evidence linking the mesosiderites and HEDs includes: (i) their nearly

  15. [In Process Citation].

    PubMed

    Aguilar Cordero, María José; Rodríguez Blanquet, Raquel; Sánchez García, Juan Carlos; Sánchez López, Antonio Manuel; Baena García, Laura; López Contreras, Gracia

    2016-01-01

    , nivel de autopercepción de salud, calidad del sueño y esfuerzo percibido durante la actividad física; b) fetales: peso, test de Apgar, perímetro cefálico y SG (semana de gestación al nacimiento); c) periparto: tiempos de dilatación, expulsivo y alumbramiento, tipo de parto, presencia de episiotomía, tipo de alimentación que recibe el RN y tiempo de lactancia materna exclusiva; y d) descriptivas: edad, profesión, nivel de estudios, tipo de ejercicio físico realizado previamente y FO (fórmula obstétrica).Conclusión: con la actividad física acuática moderada, por parte de la embarazada (método SWEP), se pretenden mejorar las variables arriba indicadas. PMID:27019255

  16. Hydrodynamic model of cells for designing systems of urban groundwater drainage

    NASA Astrophysics Data System (ADS)

    Zimmermann, Eric; Riccardi, Gerardo

    2000-08-01

    érée comme satisfaisante dans tous les cas. Afin de simuler des situations plus complexes, la nouvelle version proposée, CELSUB3, a été mise en œuvre dans un projet destiné à contrôler le niveau de la nappe à l'intérieur d'un système d'égouts, dans la ville de Chaar Ladeado (province de Santa Fe, Argentine). Différentes organisations du projet de drainage, qui ont été testées pour des conditions de recharge dynamique causées par la pluie au cours d'une année critique (la plus humide de la chronique disponible) et une année typique, sont brièvement décrites. Après analyse de dix organisations différentes, la meilleure solution technico-économique retenue est un système de drainage souterrain de conduites avec des stations de pompage et des canaux d'évacuation. Resumen. Se presenta un modelo matemático hidrodinámico cuasi-bidimensional de celdas, CELSUB3, apto para la simulación integral de sistemas de drenaje subterráneo basados en campos de bombeo o drenes subsuperficiales. El modelo de simulación presenta un ensamble de algoritmos, previamente desarrollados y testeados, que representan al escurrimiento a través del medio poroso saturado, escurrimiento en conducciones cerradas, estaciones de bombeo, etc. En la estructura del modelo se propone un nuevo tipo de vinculación entre celdas acuíferas y conductos de drenaje, la cual es verificada en problemas simples con solución analítica conocida arrojando, en todos los casos, resultados satisfactorios. Abordando situaciones más complejas, la nueva versión propuesta fue aplicada en un proyecto de control de niveles freáticos que acompaña un sistema de conductos cloacales, en la localidad de Chañar Ladeado, Santa Fe, Argentina. Se describen las alternativas de drenaje consideradas las cuales fueron evaluadas bajo recargas dinámicas provocadas por años críticamente lluviosos y en situaciones típicas. Los resultados derivados permitieron definir, tras analizar una decena de proyectos

  17. Using operational data to estimate the reliable yields of water-supply wells

    NASA Astrophysics Data System (ADS)

    Misstear, Bruce D. R.; Beeson, Sarah

    èrement importantes quand il s'agit de puits dans des aquifères fissurés, libres et peu profonds, dans lesquels la performance réelle d'un puits peut varier considérablement de celle prédite à partir d'une approche plus analytique. Des données essentielles dans les processus d'estimation de la productivité sont l'identification d'un niveau piézométrique de pompage le plus profond possible et le recueil de données opérationnelles appropriées concernant le puits et l'aquifère. Bien qu'elle ait été développée pour des opérateurs gérant des captages en Grande-Bretagne, cette approche de l'estimation de la productivité des puits de captage d'eau potable à partir de données opérationnelles peut être appliquée à une large gamme de conditions hydrogéologiques en d'autres lieux. Resumen La productividad de un pozo de abastecimiento depende de varios factores, entre los que se incluyen las propiedades del pozo y del acuífero, la capacidad de la bomba, las obras de mantenimiento, la interferencia de otras captaciones y las restricciones impuestas por permisos legales, calidad del agua y aspectos ambientales. Se ha desarrollado una metodología relativamente simple para estimar la productividad de un pozo teniendo en cuenta todos los factores previamente mencionados. Esta metodología se basa principalmente en el análisis de niveles y caudales cuando estos datos están disponibles. Se requieren buenos datos de operación, principalmente cuando el pozo está situado en un acuífero de poco espesor, no confinado y en medio fracturado, donde la respuesta del sistema puede diferir enormemente de la predicción analítica. Un punto destacado en el estudio de productividad es la identificación del descenso máximo admisible. Aunque desarrollada para el Reino Unido, la metodología puede ser utilizada a un amplio rango de condiciones hidrogeológicas en otras zonas del mundo.

  18. Exploration of an alluvial aquifer in Oman by time-domain electromagnetic sounding

    NASA Astrophysics Data System (ADS)

    Young, M. E.; de Bruijn, R. G. M.; Al-Ismaily, A. Salim

    sont grossièrement caractérisés par des différentes gammes de résistivitéélectrique se recouvrant, dépendant surtout de la teneur en argiles et du degré de cimentation. Les résistivités près de la côte diminuent du fait de l'intrusion marine. Ces variations de résistivité ont été cartographiées à partir de 400km de profils électromagnétiques, dans le domaine temporel ; trois zones ont été distinguées dans l'aquifère alluvial. Le biseau salé a aussi été délimité, jusqu'à 10km de la côte. L'épaisseur de la partie saturée des graviers va de 20-160m sur une étendue supérieure à 600km2. Resumen Un tercio de la población de Omán depende de las aguas subterráneas extraídas del aluvial de la Llanura de Batinah, en la costa del Golfo de Omán. Para determinar la profundidad y naturaleza del aluvial, así como los límites del acuífero, se han usado técnicas de exploración geofísica profunda. El basamento y los límites estructurales del aluvial en su contacto con los sedimentos marinos del Terciario y la ofiolita cretácica se obtuvieron mediante sísmica de reflexión, registrada previamente en campañas de exploración petrolífera. La base del aluvial buza hacia el norte desde el pie de las Montañas del Norte de Omán, alcanzando una profundidad máxima de 2000m en la costa. Las distintas facies del aluvial están caracterizadas por rangos distintos, pero superpuestos, de resistividad eléctrica, dependiendo del contenido en arcillas y del grado de cementación. Las resistividades cerca de la costa se reducen por la intrusión salina. Estas variaciones de resistividad se obtuvieron con registros electromagnéticos a lo largo de un perfil de 400km, con el objetivo de distinguir las tres zonas del acuífero aluvial. También se pudo obtener la geometría de la cuña de intrusión, que llega hasta 10km de la costa. El espesor de las gravas saturadas que forman el acuífero oscila entre los 20-160m en un área superior a 600km2.

  19. Dinámica y crecimiento de los granos de polvo en la nebulosa protoplanetaria

    NASA Astrophysics Data System (ADS)

    de La Fuente Marcos, Carlos

    2001-06-01

    corriente no circulares perturba significativamente el movimiento de las partículas alrededor del Sol e incrementa su vida media en la Nebulosa. El flujo medio del gas se modela de forma simple, analizándose la dinámica y el crecimiento de las partículas mediante simulaciones numéricas. Al incrementarse la vida media y la densidad superficial de las partículas sólidas, los mecanismos de confinamiento derivados de la presencia de vórtices y ondas espirales actuan sobre el material sólido de la Nebulosa (mediante agregación colisional o inestabilidades gravitacionales) de manera mucho más eficiente que la previamente considerada. Esto ofrece nuevas posibilidades para la formación de planetesimales y núcleos de planetas gigantes, y puede explicar la formación rápida de planetas extrasolares gigantes. Además, esta Tesis analiza la respuesta de las partículas, en un disco protoplanetario con un radio de 100 UA en torno a una estrella de tipo solar, al campo gravitatorio derivado de la presencia de dos estrellas compañeras ligadas en una órbita relativamente elongada (300-1600 UA). Para llevar a cabo este análisis, se han realizado una serie de simulaciones numéricas de configuraciones jerárquicas coplanares utilizando un programa FORTRAN que integra directamente las ecuaciones del movimiento con el objeto de modelar la presencia de las fuerzas gravitacionales y viscosas. El disco protoplanetario masivo se encuentra en torno a una de las componentes de la binaria. La evolución temporal del subdisco de polvo depende directamente de la naturaleza (directa o retrógrada) de la revolución relativa de la compañera estelar, y de la temperatura y la masa del disco circunestelar.

  20. Groundwater capture processes under a seasonal variation in natural recharge and discharge

    NASA Astrophysics Data System (ADS)

    Maddock, Thomas, III.; Vionnet, Leticia Beatriz

    piézométrie initiale unique et à un seul jeu de données de conditions aux limites conduit à un mauvais calcul des prélèvements. Il faut alors utiliser une condition de recharge initiale pour chaque saison. Cette approche peut être réalisée en déterminant des solutions permanentes périodiques, variantes au cours des saisons, mais se répétant d'année en année. Un modèle de nappe régional, précédemment mis au point pour une partie du bassin de la rivière San Pedro (Arizona, États-Unis), a été modifié pour illustrer l'effet de conditions initiales différentes sur des solutions transitoires et sur le calcul des prélèvements. Resumen Se define como "captura" al aumento de recarga y descenso de descarga que tiene lugar cuando se impone un bombeo en un acuífero en estado de equilibrio dinámico. Se suelen utilizar modelos regionales de agua subterránea para calcular la captura en un procedimiento que consta de dos etapas. Una solución en régimen estacionario proporciona la distribución inicial de niveles piezométricos, los flujos a través de los contornos de la región modelada y el punto de partida para el cálculo de la captura. Las soluciones transitorias proporcionan los cambios en los flujos a través de los contornos. La diferencia entre las soluciones estacionaria y transitoria da el valor de la captura. Cuando los cambios estacionales son importantes, la utilización de un único estado inicial de niveles y de flujos en los contornos da lugar a errores en el cálculo de la captura. En este caso debe usarse una condición inicial para cada una de las estaciones. Esto se puede conseguir obteniendo soluciones periódicas estacionarias, que varíen a lo largo de las estaciones, pero que se repitan año a año. Un modelo regional desarrollado previamente para el estudio de una parte de la cuenca del Río San Pedro, en Arizona (EE.UU.) se modificó para ilustrar el efecto que las distintas condiciones iniciales tienen en el cálculo de la

  1. Hydrodynamic model of cells for designing systems of urban groundwater drainage

    NASA Astrophysics Data System (ADS)

    Zimmermann, Eric; Riccardi, Gerardo

    2000-08-01

    érée comme satisfaisante dans tous les cas. Afin de simuler des situations plus complexes, la nouvelle version proposée, CELSUB3, a été mise en œuvre dans un projet destiné à contrôler le niveau de la nappe à l'intérieur d'un système d'égouts, dans la ville de Chaar Ladeado (province de Santa Fe, Argentine). Différentes organisations du projet de drainage, qui ont été testées pour des conditions de recharge dynamique causées par la pluie au cours d'une année critique (la plus humide de la chronique disponible) et une année typique, sont brièvement décrites. Après analyse de dix organisations différentes, la meilleure solution technico-économique retenue est un système de drainage souterrain de conduites avec des stations de pompage et des canaux d'évacuation. Resumen. Se presenta un modelo matemático hidrodinámico cuasi-bidimensional de celdas, CELSUB3, apto para la simulación integral de sistemas de drenaje subterráneo basados en campos de bombeo o drenes subsuperficiales. El modelo de simulación presenta un ensamble de algoritmos, previamente desarrollados y testeados, que representan al escurrimiento a través del medio poroso saturado, escurrimiento en conducciones cerradas, estaciones de bombeo, etc. En la estructura del modelo se propone un nuevo tipo de vinculación entre celdas acuíferas y conductos de drenaje, la cual es verificada en problemas simples con solución analítica conocida arrojando, en todos los casos, resultados satisfactorios. Abordando situaciones más complejas, la nueva versión propuesta fue aplicada en un proyecto de control de niveles freáticos que acompaña un sistema de conductos cloacales, en la localidad de Chañar Ladeado, Santa Fe, Argentina. Se describen las alternativas de drenaje consideradas las cuales fueron evaluadas bajo recargas dinámicas provocadas por años críticamente lluviosos y en situaciones típicas. Los resultados derivados permitieron definir, tras analizar una decena de proyectos

  2. The conceptualization model problem—surprise

    NASA Astrophysics Data System (ADS)

    Bredehoeft, John

    2005-03-01

    que le modèle conceptuel peut bien changer lorsque des nouvelles informations apparaissent. Dans l'analyse finale le hydrogéologue prend une décision subjective sur le modèle conceptuel approprié. Le problème du le modèle conceptuel ne doit pas rendre le modèle inutilisable. Ce problème introduit une incertitude qui n'est pas toujours reconnue. Les incertitudes du modèle conceptuel deviennent plus importantes dans les cases de prévisions à long terme dans l'analyse de performance. La base para hacer un análisis de un modelo es el modelo conceptual. Se define aquí la sorpresa como los datos nuevos que convierten en incoherente al modelo conceptual previamente aceptado; tal como se define aquí esto representa un cambio de paradigma. Los datos empíricos limitados indican que estas sorpresas suceden entre un 20 a un 30% de los análisis de modelos. Esto sugiere que los analistas de modelos de agua subterránea tienen dificultades al seleccionar el modelo conceptual apropiado. No hayotra solución disponible a este problema del modelo conceptual diferente de: (1) Recolectar tanta información como sea posible, mediante la utilización de todos los métodos aplicables, lo cual puede resultar en que esta nueva información ayude a cambiar el modelo conceptual vigente, y (2) Que el analista de modelos se mantenga siempre abierto al hecho de que un modelo conceptual puede cambiar de manera total, en la medida en que se colecte mas información. En el análisis final el hidrogeólogo toma una decisión subjetiva en cuanto al modelo conceptual apropiado. El problema de la conceptualización no produce modelos inútiles. El problema presenta una incertidumbre, la cual a menudo no es tenida en cuentade manera adecuada. Esta incertidumbre en los modelos conceptuales se aumenta, cuando se hacen predicciones a largo plazo del comportamiento de un sistema dado.

  3. Feasibility and effectiveness of two community-based HIV testing models in rural Swaziland

    PubMed Central

    Parker, Lucy Anne; Jobanputra, Kiran; Rusike, Lorraine; Mazibuko, Sikhathele; Okello, Velephi; Kerschberger, Bernhard; Jouquet, Guillaume; Cyr, Joanne; Teck, Roger

    2015-01-01

    ) en zonas rurales de Suazilandia. Métodos Las estrategias utilizadas fueron la de APV en instalaciones clínicas móviles (APVM) y el APV realizado en el hogar (APVBH). Se obtuvo información sobre la edad, el sexo, la realización de pruebas anteriores y resultados de VIH de los informes rutinarios de APV. A una serie consecutiva de individuos que habían dado positivo en la prueba de VIH se les siguió durante 6 meses a partir del día de la prueba, con el fin de evaluar la conexión posterior a los cuidados y tratamiento adecuados. Resultados Se evaluaron 9,060 personas: 2,034 mediante APVM y 7,026 mediante APVBH. A una mayor proporción de niños y adolescentes (<20 años) se les realizó la prueba mediante APVBH que mediante APVM (57% vs. 17%; p<0.001). El APVM llegó a una mayor proporción de hombres adultos que el APVBH (42% vs. 39%; p=0.015). De 398 individuos VIH positivos, solo 135 (34%) estaban recibiendo atención y cuidados para el VIH después de 6 meses. De 42 individuos elegibles para Terapia Antirretroviral, 22 (52%) comenzaron el tratamiento dentro de los 6 meses siguientes a la prueba. La vinculación a los cuidados y atención para VIH posterior a la prueba era menor entre aquellos que habían dado previamente positivo y aquellos con edades entre 20-40 años. El APVBH era un 50% más barato (US$11 por persona a la que se le realizó la prueba, $797 por individuo recibiendo cuidados para VIH) que el APVM ($24 y $1698, respectivamente). Conclusión En este emplazamiento con una alta prevalencia de VIH, un programa de prueba para el VIH basado en la comunidad alcanzó un alto nivel de aceptación de la prueba, y parece ser una manera efectiva y económicamente asumible de animar a un gran número de personas a conocer su estatus de VIH (en particular población actualmente poco alcanzada como los hombres y personas jóvenes). Sin embargo, para que el APV comunitario tenga un impacto sobre la mortalidad y la incidencia, es necesario implementar

  4. Quality of surgical care in hospitals providing internship training in Kenya: a cross sectional survey.

    PubMed Central

    Mwinga, Stephen; Kulohoma, Colette; Mwaniki, Paul; Idowu, Rachel; Masasabi, John; English, Mike

    2015-01-01

    los resultados y procesos de cuidados para condiciones prioritarias especificadas previamente (traumatismo craneoencefálico, lesión torácica, fracturas, quemaduras y abdomen agudo) mediante la auditoría de historias clínicas. Resultados Cada hospital tenía al menos un cirujano consultor. Se entregaban una vez por semana las listas de intervenciones quirúrgicas programadas en clínicas ambulatorias, en las rondas de visitas a las principales salas y las cirugías electivas (medio día) en 91%, 55% y 9% de los hospitales, respectivamente. En los demás hospitales se llevaban a cabo dos veces por semana. Los medicamentos básicos no estaban siempre disponibles (ej. gentamicina, morfina y meperidina en 50%, penicilina anti-estafilocócica inyectable 5% de los hospitales). Menos de la mitad de los hospitales tenían todos los recursos necesarios para proveer oxígeno. En 145 de 956 casos evaluados se llevó a cabo la cirugía con anestesia general o intradural. Encontramos apuntes quirúrgicos para un 99% y registros de la anestesia para el 72%. Se tenían registros de los signos vitales pre-quirúrgicos en un 80% de los casos y evidencia del consentimiento del paciente a ser intervenido en un 78%. Se documentaba pérdida de sangre solo en un caso y conteo de esponjas e instrumental en un 7%. Conclusiones La evaluación de los servicios quirúrgicos podría mejorarse mediante el desarrollo y la diseminación de estándares de cuidados precisos. Este estudio sugiere que los hospitales universitarios podrían estar mal equipados y los cuidados documentados sugieren que existen deficiencias tanto a nivel calidad como en el entrenamiento. PMID:25348925