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Sample records for vacas prenhes previamente

  1. Pleiotropic actions of Helicobacter pylori vacuolating cytotoxin, VacA.

    PubMed

    Isomoto, Hajime; Moss, Joel; Hirayama, Toshiya

    2010-01-01

    Helicobacter pylori produces a vacuolating cytotoxin, VacA, and most virulent H. pylori strains secrete VacA. VacA binds to two types of receptor-like protein tyrosine phosphatase (RPTP), RPTPalpha and RPTPbeta, on the surface of host cells. VacA bound to RPTPbeta, relocates and concentrates in lipid rafts in the plasma membrane. VacA causes vacuolization, membrane anion-selective channel and pore formation, and disruption of endosomal and lysosomal activity in host cells. Secreted VacA is processed into p33 and p55 fragments. The p55 domain not only plays a role in binding to target cells but also in the formation of oligomeric structures and anionic membrane channels. Oral administration of VacA to wild-type mice, but not to RPTPbeta knockout mice, resulted in gastric ulcers, in agreement with the clinical effect of VacA. VacA with s1/m1 allele has more potent cytotoxic activity in relation to peptic ulcer disease and appears to be associated with human gastric cancer. VacA activates pro-apoptotic Bcl-2 family proteins, and induces apoptosis via a mitochondria-dependent pathway. VacA can disrupt other signal transduction pathways; VacA activates p38 MAPK, enhancing production of IL-8 and PGE(2), and PI3K/Akt, suppressing GSK-3beta activity. VacA has immunomodulatory actions on T cells and other immune cells, possibly contributing to the chronic infection seen with this organism. H. pylori virulence factors including VacA and CagA, which is encoded by cytotoxin-associated gene A, along with host genetic and environmental factors, constitute a complex network to regulate chronic gastric injury and inflammation, which is involved in a multistep process leading to gastric carcinogenesis. PMID:20046046

  2. Paired cysteine residues are required for high levels of the Helicobacter pylori autotransporter VacA.

    PubMed

    Letley, Darren P; Rhead, Joanne L; Bishop, Keith; Atherton, John C

    2006-05-01

    The Helicobacter pylori vacuolating cytotoxin VacA shares homology in its C-terminal domain with many autotransporter proteins, suggesting a similar mechanism of secretion. Like most autotransporters, VacA contains a single pair of cysteine residues located near the C-terminus of the passenger domain. This study aimed to investigate the role of these conserved cysteine residues. This involved changing each cysteine in the VacA passenger domain to serine, quantifying the effect on VacA levels and assessing toxin activity in H. pylori. It was shown that both cysteine residues were required for high VacA levels, although mutation of each cysteine reduced toxin amounts to differing extents, implying that their importance was not simply for intramolecular disulphide bond formation. Although less VacA was observed for the cysteine mutants, vacuolating activity was detected, showing that the cysteines were not required for VacA function. PMID:16622049

  3. Construction of a prokaryotic expression system of vacA gene and detection of vacA gene, VacA protein in Helicobacter pylori isolates and ant-VacA antibody in patients’ sera

    PubMed Central

    Yan, Jie; Mao, Ya-Fei

    2004-01-01

    AIM: To construct a recombinant prokaryotic expression vector inserted with Helicobacter pylori vacA gene and identify the immunity of the expressed recombinant protein, and to determine prevalence of vacA-carrying/VacA expressing H pylori isolates and seroprevalence of specific ant-VacA antibody in H pylori infected patients. METHODS: Polymerase chain reaction technique was used to amplify complete vacA gene of H pylori strain NCTC11637 and to detect vacA gene in 109 H pylori isolates. The amplification product of the complete vacA gene was sequenced after T-A cloning. A recombinant expression vector inserted with a complete vacA gene fragment, named as pET32a-vacA, was constructed. Expression of the target recombinant protein VacA (rVacA) was examined by SDS-PAGE. Western blot using commercial antibodies against whole cell of H pylori and an immunodiffusion assay using self-prepared rabbit anti-rVacA antibody were applied to determine immunoreaction and antigenicity of rVacA. Two ELISA methods were established to detect VacA expression in H pylori isolates and the specific anti-VacA antibody in sera from 125 patients infected with H pylori. RESULTS: In comparison with the reported corresponding sequences, homologies of nucleotide and putative amino acid sequences of the cloned vacA gene were 99.82% and 100%, respectively. The constructed recombinant prokaryotic expression system efficiently produced rVacA. rVacA was able to combine with the commercial antibodies against whole cell of H pylori and to induce the immunized rabbit to produce specific antibody with an immunodiffusion titer of 1:4. All tested H pylori isolates carried vacA gene, but only 66.1% expressed VacA protein. Of the serum samples tested, 42.4% were positive for specific anti-VacA antibody. CONCLUSION: A prokaryotic expression system of H pylori vacA gene was successfully constructed. The expressed rVacA can be used to detect specific anti-VacA antibody in human and to prepare antiserum in animals. The high frequency of vacA gene in H pylori isolates, but with a low frequency of VacA expression and specific anti-VacA antibody in H pylori infected patients implies that VacA is not an ideal antigen for H pylori vaccine. PMID:15052679

  4. Diverse eucritic pebbles in the Vaca Muerta mesosiderite

    NASA Technical Reports Server (NTRS)

    Rubin, Alan E.; Jerde, Eric A.

    1987-01-01

    Seven 5-cm basaltic pebbles from the Vaca Muerta mesosiderite were studied by neutron activation and electron microprobe analysis, and three additional pebbles were studied petrographically. The cumulate pebbles had low REE concentrations and high Eu/Sm ratios, indicating the absence of intercumulus liquid. Siderophile interelement ratios were similar to those found in Vaca Muerta metal except for anomalously low Ir concentrations. The presence of 20 percent impact-melt breccias among the pebbles and 35-40 percent melt breccias among the mesosiderite whole-rocks suggests that the mesosiderites were more extensively impact melted than the howardites. Three alternative models to explain this greater proportion of impact-melted material among the mesosiderites are proposed.

  5. Diverse eucritic pebbles in the Vaca Muerta mesosiderite

    NASA Astrophysics Data System (ADS)

    Rubin, A. E.; Jerde, E. A.

    1987-06-01

    Seven 5-cm basaltic pebbles from the Vaca Muerta mesosiderite were studied by neutron activation and electron microprobe analysis, and three additional pebbles were studied petrographically. The cumulate pebbles had low REE concentrations and high Eu/Sm ratios, indicating the absence of intercumulus liquid. Siderophile interelement ratios were similar to those found in Vaca Muerta metal except for anomalously low Ir concentrations. The presence of 20 percent impact-melt breccias among the pebbles and 35-40 percent melt breccias among the mesosiderite whole-rocks suggests that the mesosiderites were more extensively impact melted than the howardites. Three alternative models to explain this greater proportion of impact-melted material among the mesosiderites are proposed.

  6. Helicobacter pylori VacA Subdomain Required for Intracellular Toxin Activity and Assembly of Functional Oligomeric Complexes▿

    PubMed Central

    Ivie, Susan E.; McClain, Mark S.; Torres, Victor J.; Algood, Holly M. Scott; Lacy, D. Borden; Yang, Rong; Blanke, Steven R.; Cover, Timothy L.

    2008-01-01

    Helicobacter pylori VacA is a secreted pore-forming toxin that is comprised of two domains, designated p33 and p55. The p55 domain has an important role in the binding of VacA to eukaryotic cell surfaces. A total of 111 residues at the amino terminus of p55 (residues 312 to 422) are essential for the intracellular activity of VacA, which suggests that this region may constitute a subdomain with an activity distinct from cell binding. To investigate the properties of this subdomain, a small deletion mutation (targeting aspartic acid 346 and glycine 347) was introduced into the H. pylori chromosomal vacA gene. Similar to wild-type VacA, the VacA Δ346-347 mutant protein was proteolytically processed, secreted, and bound to eukaryotic cells. However, VacA Δ346-347 did not cause cell vacuolation or membrane depolarization, and it was impaired in the ability to assemble into large water-soluble oligomeric structures. Interestingly, VacA Δ346-347 was able to physically interact with wild-type VacA to form mixed oligomeric complexes, and VacA Δ346-347 inhibited wild-type vacuolating activity in a dominant-negative manner. These data indicate that the assembly of functional oligomeric VacA complexes is dependent on specific sequences, including amino acids 346 and 347, within the p55 amino-terminal subdomain. PMID:18443094

  7. Structural Analysis of the Oligomeric States of Helicobacter pylori VacA Toxin

    PubMed Central

    Chambers, Melissa G.; Pyburn, Tasia M.; González-Rivera, Christian; Collier, Scott E.; Eli, Ilyas; Yip, Calvin K.; Takizawa, Yoshimasa; Lacy, D. Borden; Cover, Timothy L.; Ohi, Melanie D.

    2013-01-01

    Helicobacter pylori is a Gram-negative bacterium that colonizes the human stomach and contributes to peptic ulceration and gastric adenocarcinoma. H. pylori secretes a pore-forming exotoxin known as vacuolating toxin (VacA). VacA contains two distinct domains, designated p33 and p55, and assembles into large “snowflake”-shaped oligomers. Thus far, no structural data are available for the p33 domain, which is essential for membrane channel formation. Using single-particle electron microscopy and the random conical tilt approach, we have determined the three-dimensional structures of six VacA oligomeric conformations at ~15-Å resolution. The p55 domain, composed primarily of β-helical structures, localizes to the peripheral arms, while the p33 domain consists of two globular densities that localize within the center of the complexes. By fitting the VacA p55 crystal structure into the electron microscopy densities, we have mapped inter-VacA interactions that support oligomerization. In addition, we have examined VacA variants/mutants that differ from wild-type (WT) VacA in toxin activity and/or oligomeric structural features. Oligomers formed by VacAΔ6–27, a mutant that fails to form membrane channels, lack an organized p33 central core. Mixed oligomers containing both WT and VacAΔ6–27 subunits also lack an organized core. Oligomers formed by a VacA s2m1 chimera (which lacks cell-vacuolating activity) and VacAΔ301–328 (which retains vacuolating activity) each contain p33 central cores similar to those of WT oligomers. By providing the most detailed view of the VacA structure to date, these data offer new insights into the toxin's channel-forming component and the intermolecular interactions that underlie oligomeric assembly. PMID:23178866

  8. Polymorphisms in the Intermediate Region of VacA Impact Helicobacter pylori-Induced Disease Development? †

    PubMed Central

    Jones, Kathleen R.; Jang, Sungil; Chang, Jennifer Y.; Kim, Jinmoon; Chung, In-Sik; Olsen, Cara H.; Merrell, D. Scott; Cha, Jeong-Heon

    2011-01-01

    Helicobacter pylori is the etiological agent of diseases such as gastritis, gastric and duodenal ulcers, and two types of gastric cancers. While some insight has been gained into the etiology of these diverse manifestations, by and large, the reason that some individuals develop more severe disease remains elusive. Recent studies have focused on the roles of H. pylori toxins CagA and VacA on the disease process and have suggested that both toxins are intimately involved. Moreover, CagA and VacA are polymorphic within different H. pylori strains, and particular polymorphisms seem to show a correlation with the development of particular disease states. Among VacA polymorphisms, the intermediate region has recently been proposed to play a major role in disease outcome. In this article, we describe a detailed sequence analysis of the polymorphic intermediate region of vacA from strains obtained from a large South Korean population. We show that polymorphisms found at amino acid position 196 are associated with more severe disease manifestations. Additionally, polymorphisms found at amino acid position 231 are linked to disease in strains that carry the non-EPIYA-ABD allele of CagA. Collectively, these data help explain the impact of the VacA intermediate region on disease and lead to the hypothesis that there are allele-driven interactions between VacA and CagA. PMID:21084502

  9. Epidemiological Link between Gastric Disease and Polymorphisms in VacA and CagA? †

    PubMed Central

    Jang, Sungil; Jones, Kathleen R.; Olsen, Cara H.; Joo, Young Min; Yoo, Yun-Jung; Chung, In-Sik; Cha, Jeong-Heon; Merrell, D. Scott

    2010-01-01

    Gastritis, peptic ulcer disease, and gastric cancer are a few of the diverse disease manifestations that have been shown to be associated with infection by Helicobacter pylori. Why some individuals develop more severe forms of disease remains largely unknown. In this study, 225 South Korean strains were genotyped for vacA and then analyzed to determine if particular genotypes varied across disease state, sex, or cagA allele. Of these strains, 206 strains carried an s1/i1/m1 allele, 11 strains carried an s1/i1/m2 allele, and 8 strains carried an s1/i2/m2 allele. By using Fisher's exact test, a statistical association between variations in the cagA and vacA alleles was identified (P = 0.0007), and by using log linear modeling, this variation was shown to affect the severity of disease outcome (P = 0.027). Additionally, we present evidence that variation within the middle region of VacA contributes significantly to the distribution of vacA alleles across gender (P = 0.008) as well as the association with disease outcome (P = 0.011). In this South Korean population, the majority of H. pylori strains carry the vacA s1/i1/m1 allele and the CagA EPIYA-ABD allele. These facts may contribute to the high incidence of gastric maladies, including gastric cancer. PMID:19955279

  10. A Novel Method for Genotyping the Helicobacter pylori vacA Intermediate Region Directly in Gastric Biopsy Specimens

    PubMed Central

    Ferreira, Rui M.; Machado, Jose C.; Letley, Darren; Atherton, John C.; Pardo, Maria L.; Gonzalez, Carlos A.; Carneiro, Fatima

    2012-01-01

    The present report describes a novel method for genotyping the virulence-associated vacA intermediate (i) region of Helicobacter pylori in archive material. vacA i-region genotypes as determined by the novel method were completely concordant with those of sequence analysis and with those of functional vacuolation activity. The method was further validated directly in gastric biopsy specimens of 386 H. pylori-positive cases, and effective characterization of the vacA i region was obtained in 191 of 192 (99.5%) frozen and in 186 of 194 (95.9%) formalin-fixed paraffin-embedded gastric biopsy specimens, respectively. The genotyping method was next used to address the relationship between the vacA genotypes and the cagA status. The vacA i1 genotype was associated with vacA s1 (where s indicates signal region), vacA m1 (where m indicates middle region), and cagA-positive genotypes (P < 0.0001), while the vacA i2 genotype was closely related with vacA s2, vacA m2, and cagA-negative genotypes (P < 0.0001). The relationship between H. pylori vacA i-region genotypes and gastric disease development was subsequently evaluated in the Portuguese population. Patients infected with vacA i1 strains showed an increased risk for gastric atrophy and for gastric carcinoma, with odds ratios of 8.0 (95% confidence interval [CI], 2.3 to 27) and of 22 (95% CI, 7.9 to 63), respectively. Taken together, the results show that this novel H. pylori vacA i-region genotyping method can be applied directly to archive material, providing a fast evaluation of strain virulence determinants without the need of culture. The results further emphasize that the characterization of the vacA i region may be useful to identify patients at higher risk of gastric carcinoma development. PMID:23035185

  11. Remodeling the host environment: modulation of the gastric epithelium by the Helicobacter pylori vacuolating toxin (VacA)

    PubMed Central

    Kim, Ik-Jung; Blanke, Steven R.

    2012-01-01

    Virulence mechanisms underlying Helicobacter pylori persistence and disease remain poorly understood, in part, because the factors underlying disease risk are multifactorial and complex. Among the bacterial factors that contribute to the cumulative pathophysiology associated with H. pylori infections, the vacuolating cytotoxin (VacA) is one of the most important. Analogous to a number of H. pylori genes, the vacA gene exhibits allelic mosaicism, and human epidemiological studies have revealed that several families of toxin alleles are predictive of more severe disease. Animal model studies suggest that VacA may contribute to pathogenesis in several ways. VacA functions as an intracellular-acting protein exotoxin. However, VacA does not fit the current prototype of AB intracellular-acting bacterial toxins, which elaborate modulatory effects through the action of an enzymatic domain translocated inside host cells. Rather, VacA may represent an alternative prototype for AB intracellular acting toxins that modulate cellular homeostasis by forming ion-conducting intracellular membrane channels. Although VacA seems to form channels in several different membranes, one of the most important target sites is the mitochondrial inner membrane. VacA apparently take advantage of an unusual intracellular trafficking pathway to mitochondria, where the toxin is imported and depolarizes the inner membrane to disrupt mitochondrial dynamics and cellular energy homeostasis as a mechanism for engaging the apoptotic machinery within host cells. VacA remodeling of the gastric environment appears to be fine-tuned through the action of the Type IV effector protein CagA which, in part, limits the cytotoxic effects of VacA in cells colonized by H. pylori. PMID:22919629

  12. Vacuolating cytotoxin A (VacA), a key toxin for Helicobacter pylori pathogenesis

    PubMed Central

    Palframan, Samuel L.; Kwok, Terry; Gabriel, Kipros

    2012-01-01

    More than 50% of the world's population is infected with Helicobacter pylori (H. pylori). Chronic infection with this Gram-negative pathogen is associated with the development of peptic ulcers and is linked to an increased risk of gastric cancer. H. pylori secretes many proteinaceous factors that are important for initial colonization and subsequent persistence in the host stomach. One of the major protein toxins secreted by H. pylori is the Vacuolating cytotoxin A (VacA). After secretion from the bacteria via a type V autotransport secretion system, the 88 kDa VacA toxin (comprised of the p33 and p55 subunits) binds to host cells and is internalized, causing severe “vacuolation” characterized by the accumulation of large vesicles that possess hallmarks of both late endosomes and early lysosomes. The development of “vacuoles” has been attributed to the formation of VacA anion-selective channels in membranes. Apart from its vacuolating effects, it has recently become clear that VacA also directly affects mitochondrial function. Earlier studies suggested that the p33 subunit, but not the p55 subunit of VacA, could enter mitochondria to modulate organelle function. This raised the possibility that a mechanism separate from pore formation may be responsible for the effects of VacA on mitochondria, as crystallography studies and structural modeling predict that both subunits are required for a physiologically stable pore. It has also been suggested that the mitochondrial effects observed are due to indirect effects on pro-apoptotic proteins and direct effects on mitochondrial morphology-related processes. Other studies have shown that both the p55 and p33 subunits can indeed be efficiently imported into mammalian-derived mitochondria raising the possibility that they could re-assemble to form a pore. Our review summarizes and consolidates the recent advances in VacA toxin research, with focus on the outstanding controversies in the field and the key remaining questions that need to be addressed. PMID:22919683

  13. Prevalence of vacA, cagA and babA2 genes in Cuban Helicobacter pylori isolates

    PubMed Central

    Torres, Lino E; Melián, Karelia; Moreno, Arlenis; Alonso, Jordis; Sabatier, Carlos A; Hernández, Mayrín; Bermúdez, Ludisleydis; Rodríguez, Boris L

    2009-01-01

    AIM: To investigate the prevalence of vacuolating cytotoxin (vacA), cytotoxin associated gene A (cagA) and blood adhesion binding antigen (babA2) genotypes of Helicobacter pylori (H pylori) isolates from Cuban dyspeptic patients. METHODS: DNA was extracted from H pylori-positive cultures taken from 130 dyspeptic patients. Genotyping was performed by PCR, using specific primers for vacA (s1, s2, m1, m2), cagA and babA2 genes. Endoscopic observations and histological examinations were used to determine patient pathologies. RESULTS: vacA alleles s1, s2, m1 and m2 were detected in 96 (73.8%), 34 (26.2%), 75 (57.7%) and 52 isolates (40%), respectively, while the cagA gene was detected in 95 isolates (73.2%). One hundred and seven isolates (82.3%) were babA2-positive. A significant correlation was observed between vacAs1m1 and cagA and between vacAs1m1 and babA2 genotypes (P < 0.001 and P < 0.05, respectively) and between babA2 genotype and cagA status (P < 0.05); but, no correlation was observed between vacAs1 and babA2 genotypes. Eighty five (65.4%) and 73 (56.2%) strains were type 1 (vacAs1-cagA-positive) and “triple-positive” (vacAs1-cagA-babA2-positive), respectively, and their presence was significantly associated with duodenal ulcer (P < 0.01 and P < 0.001, respectively). CONCLUSION: The distribution of the main virulence factors in the Cuban strains in this study resembled that of the Western-type strains, and the more virulent H pylori isolates were significantly associated with duodenal ulcer, ulcer disease being the worst pathology observed in the group studied. PMID:19132771

  14. A role for the vacuolating cytotoxin, VacA, in colonization and Helicobacter pylori-induced metaplasia in the stomach.

    PubMed

    Winter, Jody A; Letley, Darren P; Cook, Katherine W; Rhead, Joanne L; Zaitoun, Abed A M; Ingram, Richard J M; Amilon, Karin R; Croxall, Nicola J; Kaye, Phillip V; Robinson, Karen; Atherton, John C

    2014-09-15

    Carriage of Helicobacter pylori strains producing more active (s1/i1) forms of VacA is strongly associated with gastric adenocarcinoma. To our knowledge, we are the first to determine effects of different polymorphic forms of VacA on inflammation and metaplasia in the mouse stomach. Bacteria producing the less active s2/i2 form of VacA colonized mice more efficiently than mutants null for VacA or producing more active forms of it, providing the first evidence of a positive role for the minimally active s2/i2 toxin. Strains producing more active toxin forms induced more severe and extensive metaplasia and inflammation in the mouse stomach than strains producing weakly active (s2/i2) toxin. We also examined the association in humans, controlling for cagPAI status. In human gastric biopsy specimens, the vacA i1 allele was strongly associated with precancerous intestinal metaplasia, with almost complete absence of intestinal metaplasia in subjects infected with i2-type strains, even in a vacA s1, cagA(+) background. PMID:24625807

  15. A Role for the Vacuolating Cytotoxin, VacA, in Colonization and Helicobacter pylori–Induced Metaplasia in the Stomach

    PubMed Central

    Winter, Jody A.; Letley, Darren P.; Cook, Katherine W.; Rhead, Joanne L.; Zaitoun, Abed A. M.; Ingram, Richard J. M.; Amilon, Karin R.; Croxall, Nicola J.; Kaye, Phillip V.; Robinson, Karen; Atherton, John C.

    2014-01-01

    Carriage of Helicobacter pylori strains producing more active (s1/i1) forms of VacA is strongly associated with gastric adenocarcinoma. To our knowledge, we are the first to determine effects of different polymorphic forms of VacA on inflammation and metaplasia in the mouse stomach. Bacteria producing the less active s2/i2 form of VacA colonized mice more efficiently than mutants null for VacA or producing more active forms of it, providing the first evidence of a positive role for the minimally active s2/i2 toxin. Strains producing more active toxin forms induced more severe and extensive metaplasia and inflammation in the mouse stomach than strains producing weakly active (s2/i2) toxin. We also examined the association in humans, controlling for cagPAI status. In human gastric biopsy specimens, the vacA i1 allele was strongly associated with precancerous intestinal metaplasia, with almost complete absence of intestinal metaplasia in subjects infected with i2-type strains, even in a vacA s1, cagA+ background. PMID:24625807

  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. 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

  18. Pathogenicity island cag, vacA and IS605 genotypes in Mexican strains of Helicobacter pylori associated with peptic ulcers

    PubMed Central

    2011-01-01

    Background Helicobacter pylori is associated with chronic gastritis, peptic ulcers, and gastric cancer. Two major virulence factors of H. pylori have been described: the pathogenicity island cag (cag PAI) and the vacuolating cytotoxin gene (vacA). Virtually all strains have a copy of vacA, but its genotype varies. The cag PAI is a region of 32 genes in which the insertion of IS605 elements in its middle region has been associated with partial or total deletions of it that have generated strains with varying virulence. Accordingly, the aim of this work was to determine the cag PAI integrity, vacA genotype and IS605 status in groups of isolates from Mexican patients with non-peptic ulcers (NPU), non-bleeding peptic ulcers (NBPU), and bleeding peptic ulcers (BPU). Methods The cag PAI integrity was performed by detection of eleven targeted genes along this locus using dot blot hybridization and PCR assays. The vacA allelic, cag PAI genotype 1 and IS605 status were determined by PCR analysis. Results Groups of 16-17 isolates (n = 50) from two patients with NPU, NBPU, and BPU, respectively, were studied. 90% (45/50) of the isolates harbored a complete cag PAI. Three BPU isolates lacked the cag PAI, and two of the NBPU had an incomplete cag PAI: the first isolate was negative for three of its genes, including deletion of the cagA gene, whereas the second did not have the cagM gene. Most of the strains (76%) had the vacA s1b/m1 genotype; meanwhile the IS605 was not present within the cag PAI of any strain but was detected elsewhere in the genome of 8% (4/50). Conclusion The patients had highly virulent strains since the most of them possessed a complete cag PAI and had a vacA s1b/m1 genotype. All the isolates presented the cag PAI without any IS605 insertion (genotype 1). Combined vacA genotypes showed that 1 NPU, 2 NBPU, and 1 BPU patients (66.6%) had a mixed infection; coexistence of H. pylori strains with different cag PAI status was observed in 1 NBPU and 2 BPU (50%) of the patients, but only two of these patients (NBPU and BPU) had different vacA genotypes. PMID:21569518

  19. The association of vacA genotypes and Helicobacter pylori-related gastroduodenal diseases in the Middle East

    PubMed Central

    Sugimoto, M.; Zali, M. R.

    2011-01-01

    The variations in the three regions of the Helicobacter pylori vacA gene, the signal (s1 and s2), intermediate (i1 and i2) and middle regions (m1 and m2), are known to cause the differences in vacuolating activities. However, it was unclear whether these vacA genotypes are associated with the development of gastric cancer and peptic ulcer in the Middle East. The aim was to identify the prevalence of vacA genotypes in the Middle East and the association with gastroduodenal diseases. We investigated the relationship of vacA genotypes to H. pylori-related disease development by meta-analysis using previous reports of 1,646 patients from the Middle East. The frequency of the vacA s1, m1 and i1 genotypes in the Middle Eastern strains was 71.5% (1,007/ 1,409), 32.8% (427/1,300) and 40.7% (59/145), respectively. Importantly, the frequency of vacA s- and m-region genotypes significantly differed between the north and south parts of the Middle East countries (P<0.001). The vacA genotypes significantly increased the risk of gastric cancer (odds ratio [OR]: 4.02, 95% confidence interval [CI]: 1.98–8.14 for the s1 genotype; 2.50, 1.62–3.85 for m1; 5.27, 1.97–14.1 for s1m1; 15.03, 4.69–48.17 for i1) and peptic ulcers (OR: 3.07, 95% CI: 2.08–4.52 for s1; 1.81, 1.36–2.42 for m1). The cagA-positive genotype frequently coincided with the s1, m1 and i1 genotypes. The vacA s- and m-region genotypes may be useful risk factors for gastrointestinal diseases in the Middle East, similar to European and American countries. Further studies will be required to evaluate the effects of the i-region genotype. PMID:19551413

  20. Role of Deletion Located between the Intermediate and Middle Regions of the Helicobacter pylori vacA Gene in Cases of Gastroduodenal Diseases?

    PubMed Central

    Ogiwara, Hiroaki; Sugimoto, Mitsushige; Ohno, Tomoyuki; Vilaichone, Ratha-Korn; Mahachai, Varocha; Graham, David Y.; Yamaoka, Yoshio

    2009-01-01

    The vacuolating cytotoxin gene of Helicobacter pylori, vacA, induces cytoplasmic vacuolation in gastric epithelial cells. Recently, the vacA intermediate (i) region, which is located between the signal (s) and middle (m) regions, was identified as a third polymorphic determinant of vacA activity. In vacA, there are approximately 81-bp deletions between the vacA i and m regions (denoted the d region). The aim was to clarify the roles of the vacA d region in relation to H. pylori-related diseases and histopathological gastric mucosal changes. We assessed the vacA signal s-, m-, i-, and d-region genotypes and cagA status in H. pylori isolates recovered from Western countries (n = 266) and East Asian countries (n = 244) by PCR. In East Asian countries, there were no relationships between the vacA genotypes and the clinical outcomes and histopathological changes. In Western countries, strains with the vacA s1, m1, i1, or d1 (no deletion) genotype significantly increased the risk for the development of gastric cancer compared with the risk from strains with the s2, m2, i2, or d2 genotype (adjusted odd ratios, 3.17 [95% confidence interval {CI}, 1.07 to 9.45] for s1, 10.65 [95% CI, 3.36 to 31.35] for m1, 8.57 [95% CI, 2.85 to 25.81] for i1, and 8.04 [95% CI, 2.67 to 24.16] for d1). The highly virulent vacA genotypes significantly enhanced neutrophil infiltration and gastric atrophy in univariant analysis, whereas only the vacA d-region genotype was significantly associated with neutrophil infiltration and gastric atrophy in both the antrum and the corpus by multiple linear regression analysis. The presence of the vacA d1 genotype in H. pylori strains could be an improved predictor of histological inflammation and the potential for atrophy compared with the presence of the vacA s-, m-, and i-region genotypes in Western countries. PMID:19726606

  1. Polymorphism in the Helicobacter pylori CagA and VacA toxins and disease

    PubMed Central

    Bridge, Dacie R.; Merrell, D. Scott

    2013-01-01

    Half of the world’s population is infected with Helicobacter pylori and approximately 20% of infected individuals develop overt clinical disease such as ulcers and stomach cancer. Paradoxically, despite its classification as a class I carcinogen, H. pylori has been shown to be protective against development of asthma, allergy, and esophageal disease. Given these conflicting roles for H. pylori, researchers are attempting to define the environmental, host, and pathogen interactions that ultimately result in severe disease in some individuals. From the bacterial perspective, the toxins, CagA and VacA, have each been shown to be polymorphic and to contribute to disease in an allele-dependent manner. Based on the notable advances that have recently been made in the CagA field, herein we review recent studies that have begun to shed light on the role of CagA polymorphism in H. pylori disease. Moreover, we discuss the potential interaction of CagA and VacA as a mediator of gastric disease. PMID:23380646

  2. CagA and VacA genotypes in peptic ulcer disease and non-ulcer dyspepsia: a case-control study

    PubMed Central

    FakhreYaseri, Hashem; Shakaraby, Mehdi; Bradaran, Hamid Reza; Soltani Arabshahi, Seyed Kamran; Fakhre Yaseri, Ali Mohammad

    2014-01-01

    Background: The cag pathogenicity island includes a number of genes, including cytotoxin-associated protein A (cagA) and vacuolating cytotoxin (vacA) genotypes, which are associated with bacterial virulence. Although the role of cagA and vacA in the virulence of Helicobacter pylori (H. pylori) is well-established in epidemiological studies, the relationship between the cagA and vacA genotypes in Iran has yet to be fully elucidated. This study compared the association between cagA and vacA genotypes between peptic ulcer disease (PUD) patients and non-ulcer dyspeptic (NUD) patients. Methods: This case control study was done on 130 patients with positive H. pylori in histological and Giemsa reports. The case group comprised 65 PUD patients, and the control group included 65 NUD patients. The presence of the cagA and vacA genotypes was determined using polymerase chain reaction (PCR) on biopsy samples, taken via endoscopy. Results: Both cagA and vacA genotypes were positive in 51.5% (17) of the PUD group and 20% (6) of the NUD group (p= 0.009), and both cagA and vacA genotypes were negative in 48.5% (16) and 80% (24) of the case and control groups, respectively (p= 0.03). CagA-positive H. pylori was detected in 41.5% (27) and 24.6% (16) of the case and control groups, respectively (p= 0.001), and vacA-positive H. pylori was found in 60% (39) and 46% (30) of the case and control groups, respectively. Conclusion: Both cagA and vacA genotypes were more prevalent in the PUD patients than in their NUD counterparts among our Iranian samples. It is seems that the determination of these two genotypes in PUD patients is a good screening tool for patient selection for endoscopy and treatment. PMID:25664305

  3. Characterization of Helicobacter pylori VacA-containing vacuoles (VCVs), VacA intracellular trafficking and interference with calcium signalling in T lymphocytes.

    PubMed

    Kern, Beate; Jain, Utkarsh; Utsch, Ciara; Otto, Andreas; Busch, Benjamin; Jiménez-Soto, Luisa; Becher, Dörte; Haas, Rainer

    2015-12-01

    The human pathogen Helicobacter pylori colonizes half of the global population. Residing at the stomach epithelium, it contributes to the development of diseases such as gastritis, duodenal and gastric ulcers, and gastric cancer. A major factor is the secreted vacuolating toxin VacA, which forms anion-selective channels in the endosome membrane that cause the compartment to swell, but the composition and purpose of the resulting VacA-containing vacuoles (VCVs) are still unknown. VacA exerts influence on the host immune response in various ways, including inhibition of T-cell activation and proliferation and suppression of the host immune response. In this study, for the first time the composition of VCVs from T cells was comprehensively analysed to investigate VCV function. VCVs were successfully isolated via immunomagnetic separation, and the purified vacuoles were analysed by mass spectrometry. We detected a set of 122 VCV-specific proteins implicated among others in immune response, cell death and cellular signalling processes, all of which VacA is known to influence. One of the individual proteins studied further was stromal interaction molecule (STIM1), a calcium sensor residing in the endoplasmic reticulum (ER) that is important in store-operated calcium entry. Live cell imaging microscopy data demonstrated colocalization of VacA with STIM1 in the ER and indicated that VacA may interfere with the movement of STIM1 towards the plasma membrane-localized calcium release activated calcium channel protein ORAI1 in response to Ca(2+) store depletion. Furthermore, VacA inhibited the increase of cytosolic-free Ca(2+) in the Jurkat E6-1 T-cell line and human CD4(+) T cells. The presence of VacA in the ER and its trafficking to the Golgi apparatus was confirmed in HeLa cells, identifying these two cellular compartments as novel VacA target structures. PMID:26078003

  4. New fossil record of a Jurassic pterosaur from Neuquen Basin, Vaca Muerta Formation, Argentina

    NASA Astrophysics Data System (ADS)

    Codorniú, Laura; Garrido, Alberto

    2013-12-01

    Discoveries of Jurassic pterosaurs in the Southern Hemisphere are extremely unusual. In Argentina, pterosaurs from the Upper Jurassic (Tithonian) have only been found in the Northwest of Patagonia (Neuquén Basin). These come from marine deposits and three specimens have been discovered up to the present. In this paper, we report a new finding from the Neuquén Basin. This material is identified as a tibiotarsus, which probably belonged to an osteologically adult individual and represents a new species of a pterodactyloid pterosaur of medium size. This discovery provides new evidence that at least two different species of pterodactyloid pterosaurs may have coexisted in Los Catutos Member, Vaca Muerta Formation, from the shallow marine deposits of the Neuquén Basin.

  5. 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

  6. Association of Nonsynonymous Substitutions in the Intermediate Region of the vacA Gene of Helicobacter pylori with Gastric Diseases in Taiwan?

    PubMed Central

    Sheu, Shew-Meei; Hung, Kuei-Hsiang; Sheu, Bor-Shyang; Yang, Hsiao-Bai; Wu, Jiunn-Jong

    2009-01-01

    The amino acid sequences corresponding to the vacA intermediate region from 39 isolates of Helicobacter pylori were investigated. The substitution of a G for the third S in the i1-type cluster B sequence (QASEGITSSK) conferred a greater risk of gastric diseases (P < 0.03; Fisher's exact test). The conserved substitutions of an F for the Y in the cluster A sequence and of an M for the second N in the i1-type cluster C sequence could be a marker of VacA in the Taiwanese strains. PMID:19020071

  7. High Diversity of vacA and cagA Helicobacter pylori Genotypes in Patients with and without Gastric Cancer

    PubMed Central

    López-Vidal, Yolanda; Ponce-de-León, Sergio; Castillo-Rojas, Gonzalo; Barreto-Zúñiga, Rafael; Torre-Delgadillo, Aldo

    2008-01-01

    Background Helicobacter pylori is associated with chronic gastritis, peptic ulcers, and gastric cancer. The aim of this study was to assess the topographical distribution of H. pylori in the stomach as well as the vacA and cagA genotypes in patients with and without gastric cancer. Methodology/Principal Findings Three gastric biopsies, from predetermined regions, were evaluated in 16 patients with gastric cancer and 14 patients with dyspeptic symptoms. From cancer patients, additional biopsy specimens were obtained from tumor centers and margins; among these samples, the presence of H. pylori vacA and cagA genotypes was evaluated. Positive H. pylori was 38% and 26% in biopsies obtained from the gastric cancer and non-cancer groups, respectively (p = 0.008), and 36% in tumor sites. In cancer patients, we found a preferential distribution of H. pylori in the fundus and corpus, whereas, in the non-cancer group, the distribution was uniform (p = 0.003). A majority of the biopsies were simultaneously cagA gene-positive and -negative. The fundus and corpus demonstrated a higher positivity rate for the cagA gene in the non-cancer group (p = 0.036). A mixture of cagA gene sizes was also significantly more frequent in this group (p = 0.003). Ninety-two percent of all the subjects showed more than one vacA gene genotype; s1b and m1 vacA genotypes were predominantly found in the gastric cancer group. The highest vacA-genotype signal-sequence diversity was found in the corpus and 5 cm from tumor margins. Conclusion/Significance High H. pylori colonization diversity, along with the cagA gene, was found predominantly in the fundus and corpus of patients with gastric cancer. The genotype diversity observed across systematic whole-organ and tumor sampling was remarkable. We find that there is insufficient evidence to support the association of one isolate with a specific disease, due to the multistrain nature of H. pylori infection shown in this work. PMID:19050763

  8. Clustering of Helicobacter pylori VacA in lipid rafts, mediated by its receptor, receptor-like protein tyrosine phosphatase beta, is required for intoxication in AZ-521 Cells.

    PubMed

    Nakayama, Masaaki; Hisatsune, Jyunzo; Yamasaki, Eiki; Nishi, Yoshito; Wada, Akihiro; Kurazono, Hisao; Sap, Jan; Yahiro, Kinnosuke; Moss, Joel; Hirayama, Toshiya

    2006-12-01

    Helicobacter pylori vacuolating cytotoxin, VacA, induces multiple effects on epithelial cells through different cellular events: one involves pore formation, leading to vacuolation, mitochondrial damage, and apoptosis, and the second involves cell signaling, resulting in stimulation of proinflammatory responses and cell detachment. Our recent data demonstrated that VacA uses receptor-like protein tyrosine phosphatase beta (RPTPbeta) as a receptor, of which five residues (QTTQP) at positions 747 to 751 are involved in binding. In AZ-521 cells, which mainly express RPTPbeta, VacA, after binding to RPTPbeta in non-lipid raft microdomains on the cell surface, is localized with RPTPbeta in lipid rafts in a temperature- and VacA concentration-dependent process. Methyl-beta-cyclodextrin (MCD) did not block binding to RPTPbeta but inhibited translocation of VacA with RPTPbeta to lipid rafts and all subsequent events. On the other hand, 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), which disrupts anion channels, did not inhibit translocation of VacA to lipid rafts or VacA-induced activation of p38 mitogen-activated protein (MAP) kinase, but inhibited VacA internalization followed by vacuolation. Thus, p38 MAP kinase activation did not appear to be required for internalization. In contrast, phosphatidylinositol-specific phospholipase C (PI-PLC) inhibited translocation, as well as p38 MAP kinase/ATF-2 activation, internalization, and VacA-induced vacuolation. Neither NPPB nor PI-PLC affected VacA binding to cells and to its receptor, RPTPbeta. Thus, receptor-dependent translocation of VacA to lipid rafts is critical for signaling pathways leading to p38 MAP kinase/ATF-2 activation and vacuolation. PMID:17030583

  9. 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

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

    PubMed Central

    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

  11. 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

  12. 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 gastric ulcer. In the southern Mexican population, the IL-1B -511C and -31T alleles and the -511C/-31T and -511T/-31T haplotypes are associated with increased risk of chronic gastritis and gastric ulcer. PMID:20979650

  13. 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

  14. Helicobacter pylori supernatants cause epithelial cytoskeletal disruption that is bacterial strain and epithelial cell line dependent but not toxin VacA dependent.

    PubMed

    Bebb, James R; Letley, Darren P; Rhead, Joanne L; Atherton, John C

    2003-06-01

    We show here that Helicobacter pylori broth culture supernatants disrupt the actin cytoskeleton of epithelial cell lines, leading to cell rounding and apoptosis through anoikis. We demonstrate that there are marked quantitative differences between strains and that there are different cell line sensitivities. By constructing VacA null isogenic mutants, we show that the effect is not due to the vacuolating cytotoxin. PMID:12761150

  15. 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.

  16. CagA and VacA polymorphisms do not correlate with severity of histopathological lesions in Helicobacter pylori-infected Greek children.

    PubMed

    Sgouras, Dionyssios N; Panayotopoulou, Effrosini G; Papadakos, Konstantinos; Martinez-Gonzalez, Beatriz; Roumbani, Aikaterini; Panayiotou, Joanna; vanVliet-Constantinidou, Cathy; Mentis, Andreas F; Roma-Giannikou, Eleftheria

    2009-08-01

    The presence of various numbers of EPIYA tyrosine phosphorylation motifs in the CagA protein of Helicobacter pylori has been suggested to contribute to pathogenesis in adults. In this prospective study, we characterized H. pylori isolates from symptomatic children, with reference to the diversity of functional EPIYA motifs in the CagA protein and vacA isotypes, and assessed the potential correlation with the histopathological manifestations of the infection. We analyzed 105 H. pylori isolates from 98 children and determined the diversity of EPIYA motifs in CagA by amplification and sequencing of the 3' variable region of the cagA gene as well as vacA isotypes for the signal, middle, and intermediate regions. CagA phosphorylation and levels of secreted IL-8 were determined following in vitro infection of AGS gastric epithelial cells. Histopathological evaluation of H. pylori colonization, activity, and severity of the associated gastritis was performed according to the updated Sydney criteria. EPIYA A (GLKN[ST]EPIYAKVNKKK), EPIYA B (Q[V/A]ASPEPIY[A/T]QVAKKVNAKI), and EPIYA C (RS[V/A]SPEPIYATIDDLG) motifs were detected in the ABC (46.6%) and ABCC (17.1%) combinations. No isolates harboring more than two EPIYA C motifs in CagA were found. The presence of isogenic strains with variable numbers of CagA EPIYA C motifs within the same patient was detected in seven cases. Occurrence of increasing numbers of EPIYA C motifs correlated strongly with presence of a high-vacuolation (s1 or s2/i1/m1) phenotype and age. A weak positive correlation was observed between vacuolating vacA genotypes and presence of nodular gastritis. However, CagA- and VacA-dependent pathogenicities were not found to contribute to severity of histopathology manifestations in H. pylori-infected children. PMID:19535517

  17. CagA and VacA Polymorphisms Do Not Correlate with Severity of Histopathological Lesions in Helicobacter pylori-Infected Greek Children? †

    PubMed Central

    Sgouras, Dionyssios N.; Panayotopoulou, Effrosini G.; Papadakos, Konstantinos; Martinez-Gonzalez, Beatriz; Roumbani, Aikaterini; Panayiotou, Joanna; vanVliet-Constantinidou, Cathy; Mentis, Andreas F.; Roma-Giannikou, Eleftheria

    2009-01-01

    The presence of various numbers of EPIYA tyrosine phosphorylation motifs in the CagA protein of Helicobacter pylori has been suggested to contribute to pathogenesis in adults. In this prospective study, we characterized H. pylori isolates from symptomatic children, with reference to the diversity of functional EPIYA motifs in the CagA protein and vacA isotypes, and assessed the potential correlation with the histopathological manifestations of the infection. We analyzed 105 H. pylori isolates from 98 children and determined the diversity of EPIYA motifs in CagA by amplification and sequencing of the 3? variable region of the cagA gene as well as vacA isotypes for the signal, middle, and intermediate regions. CagA phosphorylation and levels of secreted IL-8 were determined following in vitro infection of AGS gastric epithelial cells. Histopathological evaluation of H. pylori colonization, activity, and severity of the associated gastritis was performed according to the updated Sydney criteria. EPIYA A (GLKN[ST]EPIYAKVNKKK), EPIYA B (Q[V/A]ASPEPIY[A/T]QVAKKVNAKI), and EPIYA C (RS[V/A]SPEPIYATIDDLG) motifs were detected in the ABC (46.6%) and ABCC (17.1%) combinations. No isolates harboring more than two EPIYA C motifs in CagA were found. The presence of isogenic strains with variable numbers of CagA EPIYA C motifs within the same patient was detected in seven cases. Occurrence of increasing numbers of EPIYA C motifs correlated strongly with presence of a high-vacuolation (s1 or s2/i1/m1) phenotype and age. A weak positive correlation was observed between vacuolating vacA genotypes and presence of nodular gastritis. However, CagA- and VacA-dependent pathogenicities were not found to contribute to severity of histopathology manifestations in H. pylori-infected children. PMID:19535517

  18. Helicobacter pylori bab Paralog Distribution and Association with cagA, vacA, and homA/B Genotypes in American and South Korean Clinical Isolates

    PubMed Central

    Kang, Jieun; Kim, Jinmoon; Jang, Sungil; Cha, Ho Jin; Lee, Wan Jin; Kim, June; Romero-Gallo, Judith; Peek, Richard M.; Merrell, D. Scott; Cha, Jeong-Heon

    2015-01-01

    Helicobacter pylori genetic variation is a crucial component of colonization and persistence within the inhospitable niche of the gastric mucosa. As such, numerous H. pylori genes have been shown to vary in terms of presence and genomic location within this pathogen. Among the variable factors, the Bab family of outer membrane proteins (OMPs) has been shown to differ within subsets of strains. To better understand genetic variation among the bab genes and to determine whether this variation differed among isolates obtained from different geographic locations, we characterized the distribution of the Bab family members in 80 American H. pylori clinical isolates (AH) and 80 South Korean H. pylori clinical isolates (KH). Overall, we identified 23 different bab genotypes (19 in AH and 11 in KH), but only 5 occurred in greater than 5 isolates. Regardless of strain origin, a strain in which locus A and locus B were both occupied by a bab gene was the most common (85%); locus C was only occupied in those isolates that carried bab paralog at locus A and B. While the babA/babB/- genotype predominated in the KH (78.8%), no single genotype could account for greater than 40% in the AH collection. In addition to basic genotyping, we also identified associations between bab genotype and well known virulence factors cagA and vacA. Specifically, significant associations between babA at locus A and the cagA EPIYA-ABD motif (P<0.0001) and the vacA s1/i1/m1 allele (P<0.0001) were identified. Log-linear modeling further revealed a three-way association between bab carried at locus A, vacA, and number of OMPs from the HOM family (P<0.002). En masse this study provides a detailed characterization of the bab genotypes from two distinct populations. Our analysis suggests greater variability in the AH, perhaps due to adaptation to a more diverse host population. Furthermore, when considering the presence or absence of both the bab and homA/B paralogs at their given loci and the vacA genotype, an association was observed. Our results highlight the multifactorial nature of H. pylori mediated disease and the importance of considering how the specific combinations of H. pylori virulence genes and their multiple interactions with the host will collectively impact disease progression. PMID:26317221

  19. [Nutritional evaluation of the seeds of "ipil-ipil" (Leucaena leucocephala), "casco de vaca" (Bauhinia monandra) and scented carob (Albizia lebbeck)].

    PubMed

    Abreu Peñate, M; Bencomo Hernández, A; Sampere Díaz, E; Farrás Fernández, I; Hernández Triana, M; Porrata Maury, C; Ponce de León Boloy, I

    1988-12-01

    Chemical composition, antinutritional factors and biological protein quality of raw and autoclaved (120 degrees C for 10 min) ipil-ipil (Leucaena leucocephala), casco de vaca (Bauhinia monandra) ard algarrobo de olor (Albizia lebbeck) seeds were determined. The trypsin inhibitor activity was 29, 120, and 150 TIU/mg of sample respectively. Autoclaving eliminated 59, 33 and 100% of the activity. Bauhinia monandra seed depicted a high hemagglutinating activity which was eliminated by autoclaving. Net protein utilization of raw and autoclaved seeds was 31 and 30, 21 and 55 and 29 and 49%, respectively. All seeds were free from cyanide and alkaloids. It is concluded that the relative low protein quality of the seeds would limit their use for human consumption. PMID:3154303

  20. 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

  1. CagA phosphorylation EPIYA-C motifs and the vacA i genotype in Helicobacter pylori strains of asymptomatic children from a high-risk gastric cancer area in northeastern Brazil

    PubMed Central

    Braga, Lucia Libanez Bessa Campelo; de Oliveira, Maria Aparecida Alves; Gonçalves, Maria Helane Rocha Batista; Chaves, Fernando Kennedy; Benigno, Tiago Gomes da Silva; Gomes, Adriana Dias; Silva, Cícero Igor Simões Moura; Anacleto, Charles; Batista, Sérgio de Assis; Queiroz, Dulciene Maria Magalhães

    2014-01-01

    Helicobacter pylori infection is one of the most common infections worldwide and is associated with gastric diseases. Virulence factors such as VacA and CagA have been shown to increase the risk of these diseases. Studies have suggested a causal role of CagA EPIYA-C in gastric carcinogenesis and this factor has been shown to be geographically diverse. We investigated the number of CagA EPIYA motifs and the vacA i genotypes in H. pylori strains from asymptomatic children. We included samples from 40 infected children (18 females and 22 males), extracted DNA directly from the gastric mucus/juice (obtained using the string procedure) and analysed the DNA using polymerase chain reaction and DNA sequencing. The vacA i1 genotype was present in 30 (75%) samples, the i2 allele was present in nine (22.5%) samples and both alleles were present in one (2.5%) sample. The cagA-positive samples showed distinct patterns in the 3’ variable region of cagA and 18 of the 30 (60%) strains contained 1 EPIYA-C motif, whereas 12 (40%) strains contained two EPIYA-C motifs. We confirmed that the studied population was colonised early by the most virulent H. pylori strains, as demonstrated by the high frequency of the vacA i1 allele and the high number of EPIYA-C motifs. Therefore, asymptomatic children from an urban community in Fortaleza in northeastern Brazil are frequently colonised with the most virulent H. pylori strains. PMID:25494468

  2. 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).

  3. Sedimentology and sequence stratigraphy of a Tithonian-Valanginian carbonate ramp (Vaca Muerta Formation): A misunderstood exceptional source rock in the Southern Mendoza area of the Neuquén Basin, Argentina

    NASA Astrophysics Data System (ADS)

    Kietzmann, Diego A.; Palma, Ricardo M.; Riccardi, Alberto C.; Martín-Chivelet, Javier; López-Gómez, José

    2014-04-01

    The Vaca Muerta Formation (early Tithonian-early Valanginian) is a rhythmic succession of marls and limestones, cropping out in the Neuquén Basin, west-central Argentina. This lithostratigraphic unit was traditionally interpreted as basinal to slope deposits. Detailed facies analysis allows to differentiate seven facies associations, representing basinal to middle ramp facies of a homoclinal ramp system prograding westward from the eastern margin, and slope facies attributed to a distally steepened ramp system that progrades eastward from the Andean volcanic arc in the west. Two sequence hierarchies are recognized: five third order depositional sequences, and fifteen fourth order high-frequency sequences. Fluctuations in organic matter content within the Vaca Muerta Formation suggest relationship with depositional sequences, finding the highest values associated with transgressive system tracts. This work represents an important advance in the understanding of the sedimentary and stratigraphic evolution of this exceptional unconventional reservoir. Our sequence stratigraphic approach contributes to the understanding of the relationship between organic matter, facies, and sea-level changes.

  4. 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...

  5. 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...

  6. 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...

  7. 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.

  8. Determinants of non-toxicity in the gastric pathogen Helicobacter pylori.

    PubMed

    Letley, Darren P; Rhead, Joanne L; Twells, Rachel J; Dove, Brian; Atherton, John C

    2003-07-18

    The Helicobacter pylori vacuolating cytotoxin gene, vacA, is naturally polymorphic, the two most diverse regions being the signal region (which can be type s1 or s2) and the mid region (m1 or m2). Previous work has shown which features of vacA make peptic ulcer and gastric cancer-associated type s1/m1 and s1/m2 strains toxic. vacA s2/m2 strains are associated with lower peptic ulcer and gastric cancer risk and are non-toxic. We now define the features of vacA that determine the non-toxicity of these strains. To do this, we deleted parts of vacA and constructed isogenic hybrid strains in which regions of vacA were exchanged between toxigenic and non-toxigenic strains. We showed that a naturally occurring 12-amino acid hydrophilic N-terminal extension found on s2 VacA blocks vacuolating activity as its removal (to make the strain s1-like) confers activity. The mid region of s2/m2 vacA does not cause the non-vacuolating phenotype, but if VacA is unblocked, it confers cell line specificity of vacuolation as in natural s1/m2 strains. Chromosomal replacement of vacA in a non-toxigenic strain with vacA from a toxigenic strain confers full vacuolating activity proving that this activity is entirely controlled by elements within vacA. This work defines why H. pylori strains with different vacA allelic structures have differing toxicity and provides a rational basis for vacA typing schemes. PMID:12738773

  9. Molecular Basis of Pathogenicity in Helicobacter pylori Clinical Isolates ?

    PubMed Central

    Ramis, Ivy Bastos; Fonseca, Tesiê Leopoldo; Moraes, Ernani Pinho de; Fernandes, Márcia Silveira; Mendoza-Sassi, Raul; Rodrigues, Obirajara; Juliano, Carlos Renan Varela; Scaini, Carlos James; Almeida da Silva, Pedro Eduardo

    2010-01-01

    This study identified pathogenicity genes in 40 Helicobacter pylori clinical isolates. The cagA, vacA, and iceA genes were detected in 65%, 97.5%, and 97.5% of the isolates, respectively. The cagA, iceA1, and vacAs1a/m1 genes were related to erosive gastritis, whereas the vacAs2/m2 and iceA2 genes were associated with enanthematous gastritis. PMID:20686086

  10. 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…

  11. 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...

  12. 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 (21.2%); vacA s2m1 was the least common genotype (3%). The vacA s1 allele was found to be a risk factor for DU, vacA s2 for CG, and vacA s1 and vacA s2 for GU (all P < 0.05). The vacA s2m2 genotype was associated with the development of CG and GU compared to DU (P < 0.05). No correlation was found between vacA m or cagA and gastric diseases. CONCLUSION: The outcome of H. pylori infection is the result of interaction between bacterial genotypes and the age and sex of infected individuals. PMID:26309357

  13. A Helicobacter pylori Vacuolating Toxin Mutant That Fails To Oligomerize Has a Dominant Negative Phenotype

    PubMed Central

    Genisset, Christophe; Galeotti, Cesira L.; Lupetti, Pietro; Mercati, David; Skibinski, David A. G.; Barone, Silvia; Battistutta, Roberto; de Bernard, Marina; Telford, John L.

    2006-01-01

    Most Helicobacter pylori strains secrete a toxin (VacA) that causes massive vacuolization of target cells and which is a major virulence factor of H. pylori. The VacA amino-terminal region is required for the induction of vacuolization. The aim of the present study was a deeper understanding of the critical role of the N-terminal regions that are protected from proteolysis when VacA interacts with artificial membranes. Using a counterselection system, we constructed an H. pylori strain, SPM 326-Δ49-57, that produces a mutant toxin with a deletion of eight amino acids in one of these protected regions. VacA Δ49-57 was correctly secreted by H. pylori but failed to oligomerize and did not have any detectable vacuolating cytotoxic activity. However, the mutant toxin was internalized normally and stained the perinuclear region of HeLa cells. Moreover, the mutant toxin exhibited a dominant negative effect, completely inhibiting the vacuolating activity of wild-type VacA. This loss of activity was correlated with the disappearance of oligomers in electron microscopy. These findings indicate that the deletion in VacA Δ49-57 disrupts the intermolecular interactions required for the oligomerization of the toxin. PMID:16495552

  14. Analysis of the genotypic diversity of strains of Helicobacter pylori isolated from pediatric patients in Mexico.

    PubMed

    Mendoza-Elizalde, S; Cortés-Márquez, A C; Giono-Cerezo, S; Zuñiga, G; Consuelo-Sánchez, A; Valencia-Mayoral, P; Vigueras-Galindo, J C; Escalona-Venegas, G; Arellano-Galindo, J; Velázquez-Guadarrama, N

    2015-01-01

    Genotypic differences in Helicobacter pylori play an important role in infection. We characterized the diversity of the cagA, cagE, babA2, and vacA genes in H. pylori strains isolated from pediatric patients and the relationship between these genes and clinical disease. Additionally, we employed the Neighbor-net algorithm to predict the behavior of the genotypes of the strains isolated from patients. Of 93 patients analyzed, 32 were positive for infection. A total of 160 H. pylori strains (five isolates per positive patient) were analyzed. A total of 91% and 83% of strains possessed the cagA and cagE genes, respectively. For the vacA gene, 84% of strains possessed the s1 allele, 15% the s2 allele, 81% the m1 allele and 13.8% the m2 allele. The babA2 gene was present in 79% of strains. Infection with H. pylori strains with the vacA (s1m1) genotype was associated with risk of esophagitis and gastritis (p=0.0001). The combination of cagA and vacA (s1m1) was significantly associated with abdominal pain (p=0.002); however, EPIYA type was not significantly associated with abdominal pain. A total of 16 different genotypes were identified; the most common genotype was vacAs1m1cagA+cagE+babA2+ (47.5%). A total of 84% of pediatric patients were infected by at least two and up to five different genotypes. The network recovered two genotype groups (A: strains with vacAs1 and B: strains with vacAs2). The presence of multiple paths in the network suggests that reticulate events, such as recombination or reinfection, have contributed to the observed genotypic diversity. PMID:25445660

  15. 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

  16. Isolation and genotyping of Helicobacter pylori from untreated municipal wastewater.

    PubMed

    Lu, Yingzhi; Redlinger, Thomas E; Avitia, Raquel; Galindo, Adriana; Goodman, Karen

    2002-03-01

    For this study, we isolated Helicobacter pylori from wastewater by a series of steps beginning with immunomagnetic separation and cell culture. After Gram staining and three standard microbial tests, the 16S rRNA sequences of a total of 23 out of 37 putative H. pylori isolates were verified by PCR. Eleven H. pylori isolates were genotyped and fell into four vacA classes: those with the vacA allelic variants s1a and m1, s1b and m1, s2 and m2, or s2 and m1. Most H. pylori isolates were of the vacA s1a/m1 type, which has been shown to be associated with advanced diseases based on genotyping of H. pylori from gastric cancer patients. These results demonstrated that H. pylori survives in water and may be a potential source of H. pylori transmission, especially where water is not adequately treated. PMID:11872498

  17. A Herpesvirus Specific Motif of Epstein-Barr Virus DNA Polymerase Is Required for the Efficient Lytic Genome Synthesis

    PubMed Central

    Narita, Yohei; Sugimoto, Atsuko; Kawashima, Daisuke; Watanabe, Takahiro; Kanda, Teru; Kimura, Hiroshi; Tsurumi, Tatsuya; Murata, Takayuki

    2015-01-01

    Epstein-Barr virus (EBV) is associated with several malignancies, including Burkitt lymphoma and nasopharyngeal carcinoma. To overcome such disorders, understanding the molecular mechanisms of the EBV replication is important. The EBV DNA polymerase (Pol) is one of the essential factors for viral lytic DNA replication. Although it is well known that its C-terminal half, possessing DNA polymerase and 3’-5’ exonuclease activity, is highly conserved among Family B Pols, the NH2-terminal half has yet to be characterized in detail. In this study, we show that a stretch of hydrophobic amino acids within the pre-NH2-terminal domain of EBV Pol plays important role. In addition, we could identify the most essential residue for replication in the motif. These findings will shed light on molecular mechanisms of viral DNA synthesis and will help to develop new herpesviruses treatments. PMID:26123572

  18. A Herpesvirus Specific Motif of Epstein-Barr Virus DNA Polymerase Is Required for the Efficient Lytic Genome Synthesis.

    PubMed

    Narita, Yohei; Sugimoto, Atsuko; Kawashima, Daisuke; Watanabe, Takahiro; Kanda, Teru; Kimura, Hiroshi; Tsurumi, Tatsuya; Murata, Takayuki

    2015-01-01

    Epstein-Barr virus (EBV) is associated with several malignancies, including Burkitt lymphoma and nasopharyngeal carcinoma. To overcome such disorders, understanding the molecular mechanisms of the EBV replication is important. The EBV DNA polymerase (Pol) is one of the essential factors for viral lytic DNA replication. Although it is well known that its C-terminal half, possessing DNA polymerase and 3'-5' exonuclease activity, is highly conserved among Family B Pols, the NH2-terminal half has yet to be characterized in detail. In this study, we show that a stretch of hydrophobic amino acids within the pre-NH2-terminal domain of EBV Pol plays important role. In addition, we could identify the most essential residue for replication in the motif. These findings will shed light on molecular mechanisms of viral DNA synthesis and will help to develop new herpesviruses treatments. PMID:26123572

  19. Helicobacter pylori membrane vesicles stimulate innate pro- and anti-inflammatory responses and induce apoptosis in Jurkat T cells.

    PubMed

    Winter, Jody; Letley, Darren; Rhead, Joanne; Atherton, John; Robinson, Karen

    2014-04-01

    Persistent Helicobacter pylori infection induces chronic inflammation in the human gastric mucosa, which is associated with development of peptic ulceration, gastric atrophy, and gastric adenocarcinoma. It has been postulated that secretion of immunomodulatory molecules by H. pylori facilitates bacterial persistence, and membrane vesicles (MV), which have the potential to cross the gastric epithelial barrier, may mediate delivery of these molecules to host immune cells. However, bacterial MV effects on human immune cells remain largely uncharacterized to date. In the present study, we investigated the immunomodulatory effects of H. pylori MV with and without the vacuolating cytotoxin, VacA, which inhibits human T cell activity. We show a high degree of variability in the toxin content of vesicles between two H. pylori strains (SS1 and 60190). Vesicles from the more toxigenic 60190 strain contain more VacA (s1i1 type) than vesicles from the SS1 strain (s2i2 VacA), but engineering the SS1 strain to produce s1i1 VacA did not increase the toxin content of its vesicles. Vesicles from all strains tested, including a 60190 isogenic mutant null for VacA, strongly induced interleukin-10 (IL-10) and IL-6 production by human peripheral blood mononuclear cells independently of the infection status of the donor. Finally, we show that H. pylori MV induce T cell apoptosis and that this is enhanced by, but not completely dependent on, the carriage of VacA. Together, these findings suggest a role for H. pylori MV in the stimulation of innate pro- and anti-inflammatory responses and in the suppression of T cell immunity. PMID:24421041

  20. Helicobacter pylori Membrane Vesicles Stimulate Innate Pro- and Anti-Inflammatory Responses and Induce Apoptosis in Jurkat T Cells

    PubMed Central

    Letley, Darren; Rhead, Joanne; Atherton, John; Robinson, Karen

    2014-01-01

    Persistent Helicobacter pylori infection induces chronic inflammation in the human gastric mucosa, which is associated with development of peptic ulceration, gastric atrophy, and gastric adenocarcinoma. It has been postulated that secretion of immunomodulatory molecules by H. pylori facilitates bacterial persistence, and membrane vesicles (MV), which have the potential to cross the gastric epithelial barrier, may mediate delivery of these molecules to host immune cells. However, bacterial MV effects on human immune cells remain largely uncharacterized to date. In the present study, we investigated the immunomodulatory effects of H. pylori MV with and without the vacuolating cytotoxin, VacA, which inhibits human T cell activity. We show a high degree of variability in the toxin content of vesicles between two H. pylori strains (SS1 and 60190). Vesicles from the more toxigenic 60190 strain contain more VacA (s1i1 type) than vesicles from the SS1 strain (s2i2 VacA), but engineering the SS1 strain to produce s1i1 VacA did not increase the toxin content of its vesicles. Vesicles from all strains tested, including a 60190 isogenic mutant null for VacA, strongly induced interleukin-10 (IL-10) and IL-6 production by human peripheral blood mononuclear cells independently of the infection status of the donor. Finally, we show that H. pylori MV induce T cell apoptosis and that this is enhanced by, but not completely dependent on, the carriage of VacA. Together, these findings suggest a role for H. pylori MV in the stimulation of innate pro- and anti-inflammatory responses and in the suppression of T cell immunity. PMID:24421041

  1. Vacuolating Cytotoxin Genotypes Are Strong Markers of Gastric Cancer and Duodenal Ulcer-Associated Helicobacter pylori Strains: a Matched Case-Control Study

    PubMed Central

    Hussein, Nawfal R.; Miendje Deyi, Véronique Y.; Burette, Alain; Atherton, John C.

    2014-01-01

    The Helicobacter pylori virulence gene, cagA, and active forms of the vacuolating cytotoxin gene, vacA, are major determinants of pathogenesis. However, previous studies linking these factors to disease risk have often included patients using aspirin/nonsteroidal anti-inflammatory agents (NSAIDs) or acid-suppressing drugs, both of which may confound results. Also, particularly for gastric cancer (GC), controls have often been of quite different ages. Here, we performed a careful study in a “clean” Belgian population with gastric cancer cases age and sex matched to 4 controls and with a parallel duodenal ulcer (DU) group. As in other populations, there was a close association between the presence of cagA and the vacA s1 genotype. For GC, associations were found for vacA s1-positive (P = 0.01, odds ratio [OR], 9.37; 95% confidence interval [CI], 1.16 to 201.89), i1-positive (P = 0.003; OR, 12.08; 95% CI, 1.50 to 259.64), and cagA-positive status (P < 0.05; OR, infinity; 95% CI, 0.76 to infinity). For DU, associations were found with vacA s1 (P = 0.002; OR, 6.04; 95% CI, 1.52 to 27.87) and i1 (P = 0.004; OR, 4.35; 95% CI, 1.36 to 14.78) status but not with cagA status. Neither condition showed independent associations with the vacA m1 allele or with more biologically active forms of cagA with longer 3? variable regions. In this Belgian population, the best markers of gastric cancer- and duodenal ulcer-associated strains are the vacA s1 and i1 genotypes. This fits with experimental data showing that the s and i regions are the key determinants of vacuolating cytotoxin activity. PMID:24920772

  2. 78 FR 43193 - Combined Notice of Filings #1

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-19

    ... following electric corporate filings: Docket Numbers: EC13-125-000. Applicants: CalPeak Power LLC, CalPeak Power--Border LLC, CalPeak Power--Panoche LLC, CalPeak Power--Vaca Dixon LLC, CalPeak Power-- Enterprise LLC. Description: Application of CalPeak Power, LLC, et al. for Authorization under Section 203 of...

  3. The Apportionment of Liability for Damages between Employer and Union in Section 301 Actions Involving a Union's Breach of Its Duty of Fair Representation.

    ERIC Educational Resources Information Center

    Linsey, James L.

    1979-01-01

    Examines the meaning and application of the Supreme Court's ruling in "Vaca v Sipes" concerning the apportionment of liability between union and employers in duty of fair representation cases. Available from the Managing Editor, Mercer Law Review, Mercer University, 1400 Coleman Avenue, Macon, Georgia 31207; single lead article issue $3.50.…

  4. 78 FR 67133 - Combined Notice of Filings #1

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-08

    .... Docket Numbers: ER14-210-000. Applicants: Entergy Arkansas, Inc. Description: Entergy Arkansas, Inc... Commission received the following land acquisition reports: Docket Numbers: LA13-3-000. Applicants: CalPeak... Power--Vaca Dixon LLC Starwood Power-Midway LLC. Description: Quarterly Land Acquisition Report of...

  5. A diverse assemblage of Anacardiaceae from Oligocene sediments, Tepexi de Rodriguez, Puebla, Mexico.

    PubMed

    Ramírez, José L; Cevallos-Ferriz, Sergio R S

    2002-03-01

    Among the plants collected from the Pie de Vaca Formation of the Oligocene, of Tepexi de Rodríguez, Puebla, México are five plants of Anacardiaceae, Haplorhus medranoensis, Rhus toxicodendron, Rhus sp., Comocladia intermedia, and Pistacia marquezii represented by their leaves and/or leaflets. The past and present diversity and geographic distribution of one of these genera, Rhus, demonstrate its capability to adapt and diversify in a wide variety of environments. Leaf architecture characters of this taxon overlap with those of other genera in the family, suggesting a high degree of phenotypic plasticity. The presence in the Pie de Vaca Formation of a type of Pistacia with leaf architecture characters similar to those of Asian plants further supports a long history of exchange between low-latitude North America and Asia. Links between low-latitude North and South America and the Caribbean are suggested by the presence of Comocladia and Haplorhus. Whereas Comocladia highlights the long history of regional endemics in the area, Haplorhus, today an endemic monotypic genus of Peru, suggests exchange mechanisms between North and South America. The morphologic characters of these taxa, and those of Pseudosmodingium (Anacardiaceae), some Rosaceae, Leguminosae, and Berberidaceae, suggest that the Pie de Vaca community was established and evolved in harsh environmental conditions. The Pie de Vaca flora thus provides significant new insights into the biogeographic relationships of the low latitude vegetation of North America. PMID:21665653

  6. 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

  7. Distribution of Helicobacter pylori virulence markers in patients with gastroduodenal diseases in Pakistan

    PubMed Central

    2009-01-01

    Background Helicobacter pylori (H. pylori) infection is known to be associated with a spectrum of gastroduodenal diseases. We studied the association of H. pylori virulence markers cytotoxin-associated gene (cagA) and vacuolating associated cytotoxin gene (vacA) alleles in patients with non ulcer dyspepsia (NUD), gastric ulcer (GU), gastric carcinoma (GC) and duodenal ulcer (DU). Methods H. pylori infection established by both rapid urease test and histology were studied. The cagA and vacA allelic status was determined by polymerase chain reaction (PCR). Sequencing of vacA i1 and i2 PCR product was carried out. Results Two hundred and twenty-four patients were included, 141 (63%) were males with a mean age of 45 ± 16, range 16-83 years. The virulence marker cagA was associated with GU in 20(63%) (p = 0.04), DU in 23(72%) (p = 0.003) and GC in 29(73%) (p = 0.001) compared to NUD in 51(42%). VacA s1am1 was associated with GU in 23(72%) (p = 0.001), DU in 17(53%) (p < 0.001) and GC in 23(58%) (p = 0.003) compared to NUD in 38(32%) while vacA s1bm1 was also associated with GU in 9(28%) (p = 0.001), DU in 12(37%) (p < 0.001) and GC 11(28%) (p < 0.001) compared to NUD in 13(11%), respectively. The diagnoses of GU in 21(66%), DU in 16(50%), GC in 20(50%) and NUD in 50(42%) were associated with moderately active chronic inflammation. CagA in 55(45%) (p = 0.037), vacA s1am1 in 51(51%) (P < 0.001), s1bm1 in 25(56%) (p = 0.002), s1am2 32(30%) (p < 0.001) and s1bm2 29(69%) (p = 0.004) were also associated with moderately active chronic inflammation. Conclusion CagA was negative in majority of NUD patients with H. pylori infection. However, cagA was associated with peptic ulcer and GC. VacA allele's s1am1 and s1bm1 were associated with H. pylori associated diseases and inflammation. PMID:19930551

  8. Genotypes of Helicobacter pylori in patients with peptic ulcer bleeding

    PubMed Central

    Perng, Chin-Lin; Lin, Hwai-Jeng; Lo, Wen-Ching; Tseng, Guan-Ying; Sun, I-Chen; Ou, Yueh-Hsing

    2004-01-01

    AIM: Helicobacter pylori causes chronic gastritis, peptic ulcer, gastric cancer and MALT-lymphoma. Different genotypes of Helicobacter pylori are confirmed from diverse geographic areas. Its association with bleeding peptic ulcer remains controversial. The aim of this study was to investigate the Helicobacter pylori vacA alleles, cagA and iceA in patients with bleeding peptic ulcer. METHODS: We enrolled patients with bleeding, non-bleeding peptic ulcers and chronic gastritis. Biopsy specimens were obtained from the antrum of the stomach for rapid urease test, bacterial culture and PCR assay. DNA extraction and polymerase chain reaction were used to detect the presence or absence of cagA and to assess the polymorphism of vacA and iceA. RESULTS: A total of 168 patients (60.4%) (25 patients with chronic gastritis, 26 patients with bleeding gastric ulcer, 51 patients with non-bleeding gastric ulcer, 26 patients with bleeding duodenal ulcer, and 40 patients with non-bleeding duodenal ulcer) were found to have positive PCR results between January 2001 and December 2002. Concerning genotypes, we found cagA (139/278, 50%), vacA s1a (127/278, 45.7%), and ice A1 (125/278, 45%) predominated in all studied patients. In patients with bleeding peptic ulcers, vacA s1a and m1T were fewer than those in patients with non-bleeding peptic ulcers (37/106 vs 69/135, P = 0.017, and 4/106 vs 21/135, P = 0.002). CONCLUSION: In patients with peptic ulcers, H pylori vacA s1a and m1T prevent bleeding complication. PMID:14966926

  9. Helicobacter pylori inhibits expression of heat shock protein 70 (HSP70) in human epithelial cell line. Importance of Cag A protein.

    PubMed

    Targosz, A; Pierzchalski, P; Krawiec, A; Szczyrk, U; Brzozowski, T; Konturek, S J; Pawlik, W W

    2006-06-01

    Heat shock proteins (HSP) are crucial for the maintenance of cell integrity under normal cell growth and at pathophysiological conditions such as colonization of gastric mucosa by Helicobacter pylori (Hp). The effect of Hp on mRNA expression for HSP70 in the gastric epithelial cells in vitro has been little studied and remains inconclusive. In this study we attempted to determine the alterations in gene expression for HSP70 induced by two live strains of Hp in the epithelial MKN7 cells. The following Hp strains were employed; 1) Hp strain expressing cagA and vacA, and 2) cagA and vacA negative Hp strain without or with addiction of exogenous recombinant protein CagA. MKN7 cells were incubated in a standard medium RPMI 1640 supplemented with 10% fetal bovine serum at 37 degrees C with 5% CO2 and humidified atmosphere under basal condition or in a presence of Hp (1 x 10(9) CFU per dish) without or with the recombinant CagA (10 microg/ml of RPMI 1640 medium). After 3 h, 24 h and 48 h of incubation with Hp and in some experiments with the prolonged incubation time up to 72 h, the cells were harvested, the total cellular RNA was isolated and the expression of mRNA for HSP70 was determined by RT-PCR. The incubation of the MKN cells with CagA protein alone failed to affect significantly the expression of HSP70. In contrast, the strain Hp (cagA+, vacA+) inhibited in time-dependent manner the expression of mRNA for HSP70. When the MKN7 cells were coincubated with Hp (cagA+, vacA+) and exogenous CagA, the significant inhibition of the signal intensity for HSP70 mRNA was observed at 3 h and 24 h of incubation and these effects were followed by complete disappearance of the signal for HSP70 mRNA at 48 h. The incubation of MKN7 with Hp (cagA-, vacA-) also significantly attenuated the expression of HSP70 mRNA with the most pronounced inhibitory effect observed at 72 h of incubation with this Hp strain. Addition of the recombinant CagA to Hp (cagA-, vacA-) completely suppressed the expression of HSP70 at 48 h and 72 h after the end of incubation periods. We conclude that 1) both, Hp (cagA+, vacA+) and Hp (cagA-, vacA-) inhibit expression of HSP70 in MKN7 human gastric epithelial cells independently of the presence or absence of cagA gene, and that 2) recombinant CagA protein may exert biological activity in vitro via acceleration of inhibitory effect of Hp negative for Cag A and VacA on HSP70 expression in epithelial cells infected with this bacteria. PMID:16845230

  10. Diversity of Helicobacter pylori genotypes in Iranian patients with different gastroduodenal disorders

    PubMed Central

    Vaziri, Farzam; Najar Peerayeh, Shahin; Alebouyeh, Masoud; Mirzaei, Tabassom; Yamaoka, Yoshio; Molaei, Mahsa; Maghsoudi, Nader; Zali, Mohammad Reza

    2013-01-01

    AIM: To investigate the diversity of Helicobacter pylori (H. pylori) genotypes and correlations with disease outcomes in an Iranian population with different gastroduodenal disorders. METHODS: Isolates of H. pylori from patients with different gastroduodenal disorders were analyzed after culture and identification by phenotypic and genotypic methods. Genomic DNA was extracted with the QIAamp DNA mini kit (Qiagen, Germany). After DNA extraction, genotyping was done for cagA, vacA (s and m regions), iceA (iceA1, iceA2) and babA with specific primers for each allele using polymerase chain reaction (PCR). All patients’ pathologic and clinical data and their relation with known genotypes were analyzed by using SPSS version 19.0 software. ?2 test and Fisher’s exact test were used to assess relationships between categorical variables. The level of statistical significance was set at P < 0.05. RESULTS: A total of 71 isolates from 177 patients with different gastroduodenal disorders were obtained. Based on analysis of the cagA gene (positive or negative), vacA s-region (s1 or s2), vacA m-region (m1 or m2), iceA allelic type (iceA1 and iceA2) and babA gene (positive or negative), twenty different genotypic combinations were recognized. The prevalence of cagA, vacA s1, vacA s2, vacA m1, vacA m2, iceA1, iceA2, iceA1+iceA2 and babA were 62%, 78.9%, 19.7%, 21.1%, 78.9%, 15.5%, 22.5%, 40.8% and 95.8%, respectively. Interestingly, evaluation of PCR results for cagA in 6 patients showed simultaneous existence of cagA variants according to their size diversities that proposed mixed infection in these patients. The most prevalent genotype in cagA-positive isolates was cagA+/vacAs1m2/iceA1+A2/babA+ and in cagA-negative isolates was cagA-/vacAs1m2/iceA-/babA+. There were no relationships between the studied genes and histopathological findings (H. pylori density, neutrophil activity, lymphoid aggregation in lamina propria and glandular atrophy). The strains which carry cagA, vacAs1/m1, iceA2 and babA genes showed significant associations with severe active chronic gastritis (P = 0.011, 0.025, 0.020 and 0.031, respectively). The vacAs1 genotype had significant correlation with the presence of the cagA gene (P = 0.013). Also, babA genotype showed associations with cagA (P = 0.024). In the combined genotypes, only cagA+/vacAs1m1/iceA2/babA+ genotype showed correlation with severe active chronic gastritis (P = 0.025). CONCLUSION: This genotyping panel can be a useful tool for detection of virulent H. pylori isolates and can provide valuable guidance for prediction of the clinical outcomes. PMID:24039362

  11. Kinetics and Mechanisms of Extracellular Protein Release by Helicobacter pylori

    PubMed Central

    Schraw, Wayne; McClain, Mark S.; Cover, Timothy L.

    1999-01-01

    To investigate the kinetics and mechanisms of extracellular protein release by Helicobacter pylori, we analyzed the entry of metabolically radiolabeled bacterial proteins into broth culture supernatant. At early time points, vacuolating cytotoxin (VacA) constituted a major extracellular protein. Subsequently, culture supernatants accumulated many proteins that were components of intact bacterial cells. This nonselective release of proteins was associated with a decreasing turbidity of cultures and loss of bacterial viability, indicative of an autolytic process. The rates of VacA secretion and autolysis were each influenced by medium composition, and therefore these may be regulated phenomena. Extracellular release of proteins by H. pylori may be an important adaptation that facilitates the persistence of H. pylori in the human gastric mucus layer. Moreover, entry of proinflammatory proteins into the gastric mucosa may contribute to the induction of a mucosal inflammatory response. PMID:10496902

  12. Outer Membrane Targeting of Passenger Proteins by the Vacuolating Cytotoxin Autotransporter of Helicobacter pylori

    PubMed Central

    Fischer, Wolfgang; Buhrdorf, Renate; Gerland, Elke; Haas, Rainer

    2001-01-01

    Helicobacter pylori produces a number of proteins associated with the outer membrane, including adhesins and the vacuolating cytotoxin. These proteins are supposed to integrate into the outer membrane by ?-barrel structures, characteristic of the family of autotransporter proteins. By using the SOMPES (shuttle vector-based outer membrane protein expression) system for outer membrane protein production, we were able to functionally express in H. pylori the cholera toxin B subunit genetically fused to the C-terminal VacA domain. We demonstrate that the fusion protein is translocated to the H. pylori outer membrane and that the CtxB domain is exposed on the H. pylori surface. Thus, we provide the first experimental evidence that the C-terminal ?-domain of VacA can transport a foreign passenger protein to the H. pylori surface and hence acts as a functional autotransporter. PMID:11598049

  13. Helicobacter pylori infection in children.

    PubMed

    Vandenplas, Y; Blecker, U

    1998-11-01

    Helicobacter pylori colonizes the human stomach, especially during childhood. However, a variety of H. pylori strains exists, with major differences in virulence characteristics which probably account for different clinical symptoms, and the majority of infected subjects remains asymptomatic. Helicobacter pylori infection is correlated with socioeconomic conditions and hygienic circumstances, resulting in an extremely high prevalence in children in developing countries. Commercial screening tests are not capable of separating the more virulent strains (type I with vacuolating toxin VacA and CagA protein) from the less virulent strains (type II, VacA and CagA negative). Type I strains, but not type II, are associated with an increased risk for duodenal ulcer and gastric cancer. Therefore, future screening tests and vaccinations should focus on the type I strains. PMID:9846909

  14. Vacuolisation of human microvascular endothelial cells by enterohaemorrhagic Escherichia coli.

    PubMed

    Bielaszewska, Martina; Bauwens, Andreas; Greune, Lilo; Kemper, Björn; Dobrindt, Ulrich; Geelen, Joyce M; Kim, Kwang S; Schmidt, M Alexander; Karch, Helge

    2009-12-01

    Enterohaemorrhagic Escherichia coli (EHEC) cause haemolytic uraemic syndrome (HUS), a thrombotic microangiopathy resulting from endothelial injury in the renal glomeruli and other organs. EHEC virulence factors that damage the microvascular endothelium play therefore major roles in the pathogenesis of HUS. We identified an EHEC strain that vacuolates and kills primary human glomerular microvascular endothelial cells (GMVECs) and a human brain microvascular endothelial cell (HBMEC) line. Because the vacuolating effect closely resembles those elicited on other cells by the vacuolating cytotoxin of Helicobacter pylori (VacA), we designated the factor responsible for this effect EHEC vacuolating cytotoxin (EHEC-Vac). EHEC-Vac (a secreted non-serine protease protein) binds to HBMECs rapidly and irreversibly, vacuolates within 30 min after exposure and the effect is maximally apparent at 48 h. Despite the vacuolisation, HBMECs survive for several days before they undergo necrosis. Electron and immunofluorescence microscopy demonstrate that the vacuoles induced by EHEC-Vac originate from lysosomes. Accordingly, they stain with neutral red indicating an acidic microenvironment. Similar to VacA, the EHEC-Vac-mediated vacuolisation is both prevented and reverted by the vacuolar proton pump inhibitor bafilomycin A1, suggesting a similar mechanism of vacuole formation by these toxins. Despite the similarity of phenotypes elicited by EHEC-Vac and VacA, genomic DNA from the EHEC-Vac-producing strain failed to hybridise to a vacA probe, as well as to probes derived from presently known E. coli vacuolating toxins. Through its microvascular endothelium-injuring potential combined with the ability to induce interleukin 6 release from these cells EHEC-Vac might contribute to the pathogenesis of HUS. PMID:19967138

  15. Cyclostratigraphy of an orbitally-driven Tithonian-Valanginian carbonate ramp succession, Southern Mendoza, Argentina: Implications for the Jurassic-Cretaceous boundary in the Neuquén Basin

    NASA Astrophysics Data System (ADS)

    Kietzmann, Diego A.; Palma, Ricardo M.; Iglesia Llanos, Maria Paula

    2015-01-01

    Detailed sedimentological, sequence stratigraphical and cyclostratigraphical analyses have been made from four lower Tithonian-lower Valanginian sections of the Vaca Muerta Formation, exposed in the southern Mendoza area of the Neuquén Basin, Argentina. The Vaca Muerta Formation is characterized by decimetre-scale rhythmic alternations of marls, shales and limestones, and consists of five facies associations, which reflect different paleoenvironmental conditions: basin to restricted outer ramp, outer ramp, and middle ramp. Vertical organization within the Vaca Muerta Formation shows a well-ordered hierarchy of cycles, where elementary cycles, bundles and superbundles with frequencies within the Milankovitch band have been recognized. According to biostratigraphic data, elementary cycles have a periodicity of ~ 20 ky, which correlates with the precession cycle of Earth's axis. Spectral analysis based on series of cycle thickness allows us to identify frequencies of about 400 ky and 90-120 ky, which we interpret as the modulation of the precessional cycle by the Earth's orbital eccentricity. Cycles are probably driven by variations in carbonate exportation, as fluctuations in shallow-water carbonate production involve modifications in carbonate basinward exportation. Cyclostratigraphic data allowed us to build a floating orbital scale for the Tithonian-lower Valanginian interval in the Neuquén Basin. Correlation between studied sections allowed us to recognize a discontinuity between the Substeueroceras koeneni and Argentiniceras noduliferum ammonite zones in the Malargüe Anticline area. Orbital calibration of these sections is consistent with Riccardi's biostratigraphic scheme, wich place the Jurassic-Cretaceous boundary within the Substeueroceras koeneni ammonite Zone. On the other hand, the base of the Vaca Muerta Formation (Virgatosphinctes mendozanus ammonite Zone) would be probably placed in the base of the middle Tithonian rather than the lower Tithonian, which is also consistent with our preliminary palaeomagnetic data.

  16. 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

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

    PubMed

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

    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

  18. Determination of Helicobacter pylori Virulence Genes in Gastric Biopsies by PCR

    PubMed Central

    Hammoudeh, Wail; Sabri, Israr; Sweidan, Walid; Farraj, Mohammad A.

    2013-01-01

    Aim. The aim of this study was to identify the presence of H. pylori in biopsy specimens from symptomatic patients by PCR. In addition, the rate of cagA, vacA, iceA1, and iceA2 virulence genes was determined. Materials and Methods. One hundred antral gastric biopsy specimens were collected during endoscopy from patients suffering from gastroduodenal symptoms. The samples were collected by the gastroenterologists in their own clinics in Ramallah, Palestine. DNA was extracted from the biopsies and subsequently used for PCR identification of H. pylori and the virulence genes using specific primers. Results. The rate of positive H. pylori in the collected biopsies was 44%. The rates of the virulence genes in this sample: cagA, vacA, iceA1, and iceA2 were 65.9%, 40.9%, 63.6%, and 84.1%, respectively. Conclusion. The iceA2 gene was the most frequent in this study. Much research is necessary to determine the presence of an association of this gene with gastric pathology. Variation in the rates of the iceA gene in different countries is a strong indication of its geographical distribution. This study would provide important information regarding the prevalence of virulence genes (vacA, cagA, iceA1, and iceA2) in H. pylori strains in the sample tested in this country. PMID:23691338

  19. Helicobacter pylori Perturbs Iron Trafficking in the Epithelium to Grow on the Cell Surface

    PubMed Central

    Tan, Shumin; Noto, Jennifer M.; Romero-Gallo, Judith; Peek, Richard M.; Amieva, Manuel R.

    2011-01-01

    Helicobacter pylori (Hp) injects the CagA effector protein into host epithelial cells and induces growth factor-like signaling, perturbs cell-cell junctions, and alters host cell polarity. This enables Hp to grow as microcolonies adhered to the host cell surface even in conditions that do not support growth of free-swimming bacteria. We hypothesized that CagA alters host cell physiology to allow Hp to obtain specific nutrients from or across the epithelial barrier. Using a polarized epithelium model system, we find that isogenic ΔcagA mutants are defective in cell surface microcolony formation, but exogenous addition of iron to the apical medium partially rescues this defect, suggesting that one of CagA's effects on host cells is to facilitate iron acquisition from the host. Hp adhered to the apical epithelial surface increase basolateral uptake of transferrin and induce its transcytosis in a CagA-dependent manner. Both CagA and VacA contribute to the perturbation of transferrin recycling, since VacA is involved in apical mislocalization of the transferrin receptor to sites of bacterial attachment. To determine if the transferrin recycling pathway is involved in Hp colonization of the cell surface, we silenced transferrin receptor expression during infection. This resulted in a reduced ability of Hp to colonize the polarized epithelium. To test whether CagA is important in promoting iron acquisition in vivo, we compared colonization of Hp in iron-replete vs. iron-deficient Mongolian gerbils. While wild type Hp and ΔcagA mutants colonized iron-replete gerbils at similar levels, ΔcagA mutants are markedly impaired in colonizing iron-deficient gerbils. Our study indicates that CagA and VacA act in concert to usurp the polarized process of host cell iron uptake, allowing Hp to use the cell surface as a replicative niche. PMID:21589900

  20. 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

  1. Use of a Non-invasive Test (Entero-test) in the Detection of Helicobacter pylori in Children in an Endemic Area in Colombia

    PubMed Central

    Arboleda, Richard N; Schneider, Barbara G; Bravo, Luis E; Romero-Gallo, Judith; Peek, Richard M; Mera, Robertino M; Yepez, Maria Clara; Campo, Cristina; Correa, Pelayo

    2013-01-01

    Objectives Gastric infection with Helicobacter pylori (H. pylori), a strong risk factor for gastric cancer, is highly prevalent in children residing in the Colombian Andes. We aimed to validate the use of the Entero-test to culture and genotype H. pylori strains from asymptomatic Colombian children. Methods Children (age 10–15y, n=110, 80 of which were H. pylori-positive by the urea breath test, or UBT) were subjected to the Entero-test, and strings were cultured and/or used for DNA extraction for PCR. These children had been treated for H. pylori in 2007. A second population of children (age 10–15y, n= 95), who had not been previously treated were also subjected to the Entero-test. Results Of UBT+ children in the treated group, 29/80 (36%) Entero-test samples were H. pylori culture positive; 29 additional string extracts were tested by PCR for the H. pylori virulence factors cagA and vacA. PCR from cultures and extracts yielded a Sensitivity of 74% and Specificity of 87%. In the untreated group, 16 of 94 UBT+ children (17%) produced Entero-tests that were culture positive. Fifty-eight of 94 (62%) string extracts were PCR positive for cagA and/or vacA. In previously treated children, H. pylori strains were more often the less virulent vacA s2 (P=0.001), m2 (P=0.006), and i2 genotypes (P=0.039). Conclusions The Entero-test may be used as a non-invasive test to detect H. pylori in asymptomatic children residing in high risk areas for gastric cancer. Treatment of H. pylori in children was associated with less virulent genotypes. PMID:23880626

  2. Short-term training alters the control of mitochondrial respiration rate before maximal oxidative ATP synthesis

    PubMed Central

    Layec, Gwenael; Haseler, Luke J.; Hoff, Jan; Hart, Corey R.; Liu, Xin; Le Fur, Yann; Jeong, Eun-Kee; Richardson, Russell S.

    2013-01-01

    Aim Short-term exercise training may induce metabolic and performance adaptations before any changes in mitochondrial enzyme potential. However, there has not been a study that has directly assessed changes in mitochondrial oxidative capacity or metabolic control as a consequence of such training in vivo. Therefore, we used 31P-magnetic resonance spectroscopy (31P-MRS) to examine the effect of short-term plantar flexion exercise training on phosphocreatine (PCr) recovery kinetics and the control of respiration rate. Method To this aim, we investigated 12 healthy men, experienced with this exercise modality (TRA), and 7 time-control subjects (TC). Results After 5 days of training, maximum work rate during incremental plantar flexion exercise was significantly improved (P < 0.01). During the recovery period, the maximal rate of oxidative ATP synthesis (PRE: 28 ± 13 mM.min?1; POST: 26 ± 15 mM.min?1) and the PCr recovery time constant (PRE: 31 ± 19 s; POST: 29 ± 16) were not significantly altered. In contrast, the Hill coefficient (nH) describing the cooperativity between respiration rate and ADP was significantly increased in TRA (PRE:nH = 2.7 ± 1.4; POST: nH = 3.4 ± 1.9, P < 0.05). Meanwhile, there were no systematic variations in any of these variables in TC. Conclusion This study reveals that 5 days of training induces rapid adaptation in the allosteric control of respiration rate by ADP before any substantial improvement in muscle oxidative capacity occurs. PMID:23582030

  3. Life in the human stomach: persistence strategies of the bacterial pathogen Helicobacter pylori

    PubMed Central

    Salama, Nina R.; Hartung, Mara L.; Müller, Anne

    2013-01-01

    The bacterial pathogen Helicobacter pylori has co-evolved with humans and colonizes roughly one half of the human population, but only causes overt gastric disease in a subset of infected hosts. In this Review, we discuss the pathogenesis of this bacterium and the mechanisms it uses to promote persistent colonization of the gastric mucosa, with a focus on recent insights into the role of the virulence factors VacA, CagA and CagL. We also describe the immunobiology of H. pylori infection and highlight how this bacterium manipulates the innate and adaptive immune systems of the host to promote its own persistence. PMID:23652324

  4. 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.

  5. 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

  6. Pathogenesis of Helicobacter pylori Infection.

    PubMed

    Sgouras, Dionyssios N; Trang, Tran Thi Huyen; Yamaoka, Yoshio

    2015-09-01

    Three decades have passed since Warren and Marshall described the successful isolation and culture of Helicobacter pylori, the Gram-negative bacterium that colonizes the stomach of half the human population worldwide. Although it is documented that H. pylori infection is implicated in a range of disorders of the upper gastrointestinal tract, as well as associated organs, many aspects relating to host colonization, successful persistence, and the pathophysiological mechanisms of this bacteria still remain controversial and are constantly being explored. Unceasing efforts to decipher the pathophysiology of H. pylori infection have illuminated the crucially important contribution of multifarious bacterial factors for H. pylori pathogenesis, in particular the cag pathogenicity island (PAI), the effector protein CagA, and the vacuolating cytotoxin VacA. In addition, recent studies have provided insight into the importance of the gastrointestinal microbiota on the cumulative pathophysiology associated with H. pylori infection. This review focuses on the key findings of publications related to the pathogenesis of H. pylori infection published during the last year, with an emphasis on factors affecting colonization efficiency, cagPAI, CagA, VacA, and gastrointestinal microbiota. PMID:26372819

  7. Genotype Diversity and Quasispecies Development of Helicobacter pylori in a Single Host.

    PubMed

    Farzi, Nastaran; Malekian, Tannaz; Alebouyeh, Masoud; Vaziri, Farzam; Zali, Mohammad Reza

    2015-01-01

    Infection with different strains of Helocobacter pylori and emergence of new genomic variants during their long-term gastric colonization are assumed to be the main reasons for eradication failure. We used genotyping and arbitrarily primed PCR fingerprinting (RAPD) to detect relatedness and genetic variations among H. pylori single isolates from each patient in Iran. Multiplex-PCR amplification of gene alleles encoding the virulence factors vacA (m/s), cagA, and iceA (A1/A2) and comparison of RAPD patterns of different singles colonies were performed for each individual patient's isolate. Results showed a high frequency of diversity among the H. pylori strains. Nearly 23% of infected patients showed a single type infection. The infection types related, unrelated, and related/unrelated were found among 25.6%, 12.8%, and 38.5% of patients, respectively. Both mixed type infections (77%) and quasispecies development (15.4%) were detected in these patients. Genotype conversion among vacA (41.6%), cagA (41.6%), and iceA (50%) alleles was observed for the strains with identical or related RAPD patterns. Coevolution of different alleles was also detected in a patient infected with strains presenting the same RAPD patterns. Collectively, results of this study revealed the occurrence of quasispecies development, mixed type infections, and changes in virulence properties of H. pylori strains among the studied patients. PMID:25672355

  8. Relationship between Helicobacter pylori virulence factors and regulatory cytokines as predictors of clinical outcome

    PubMed Central

    Serrano, Carolina; Diaz, Maria Ines; Valdivia, Alejandra; Godoy, Alex; Peña, Alfredo; Rollan, Antonio; Kirberg, Arturo; Hebel, Eduardo; Fierro, Jaqueline; Klapp, Gerardo; Venegas, Alejandro; Harris, Paul R.

    2013-01-01

    H. pylori infection is highly prevalent in Chile (73%). Usually a minority of infected patients develops complications such as ulcers and gastric cancer that have been associated with the presence of virulence factors (cagA, vacA) and host T helper response (Th1/Th2). Our aim was to evaluate the relationship between strain virulence and host immune response, using a multiple regression approach for the development of a model based on data collected from H. pylori infected patients in Chile. We analyzed levels of selected cytokines determined by ELISA (IL-12, IL-10, IFN-? and IL-4) and the presence of cagA and vacA alleles polymorphisms determined by PCR in antral biopsies of 41 patients referred to endoscopy. By multiple regression analysis we established a correlation between bacterial and host factors using clinical outcome (gastritis and duodenal ulcer) as dependent variables. The selected model was described by: clinical outcome = 0.867491 (cagA) + 0.0131847 (IL-12/IL-10) + 0.0103503 (IFN-?/IL-4) and it was able to explain over 90% of clinical outcomes observations (R2=96.4). This model considers that clinical outcomes are better explained by the interaction of host immune factors and strain virulence as a complex and interdependent mechanism. PMID:17336120

  9. PCR assay targeting virulence genes of Helicobacter pylori isolated from drinking water and clinical samples in Lahore metropolitan, Pakistan.

    PubMed

    Samra, Zahoor Qadir; Javaid, Umber; Ghafoor, Sadia; Batool, Aleeza; Dar, Nadia; Athar, Muhammad Amin

    2011-03-01

    Helicobacter pylorus is considered for chronic gastritis, gastric ulcers and adenocarcinoma and its high infection rate is observed in overcrowded and lower socioeconomic groups in developing countries. This study was designed to identify the role of drinking water in the transmission and prevalence of H. pylori (HP). Selective HP medium was developed for enrichment and presumptive identification of H. pylori by urease, catalase and species specific 16S rRNA tests. The virulence genes (vacA 's' and 'm' regions and cagA) of H. pylori in 90 out of 225 H. pylori positive drinking water samples were present (40%). Ten out of 18 biopsies (55.55%) and 15 out of 50 vomiting fluids of gastric disease patients (30%) were also positive for virulence genes. Anti-H. pylori antibodies were also detected in 31 out of 50 patients' sera. The presence of virulence genes was also directly confirmed by hybridization studies using non-radioactive DNA probes of 16S rRNA, vacA and cagA genes. The presence of H. pylori in water is due to poor sanitary conditions, improper waste disposal and lack of public health education. PCR-based analysis and colony hybridization can be used for detection of H. pylori in clinical and environmental samples. PMID:21301128

  10. Mutants of TETRAHYMENA THERMOPHILA with Temperature-Sensitive Food Vacuole Formation. I. Isolation and Genetic Characterization.

    PubMed

    Suhr-Jessen, P B; Orias, E

    1979-08-01

    Germ-line mutants have been isolated in Tetrahymena thermophila that have recessive, temperature-sensitive defects in phagocytosis. Nitrosoguanidine-mutagenized cells were induced to undergo cytogamy, and clones were isolated that were unable to form food vacuoles after two days of growth at 39 degrees . Most of the mutants belong to a single complementation group, designated vacA. They have defects in oral development-not in phagocytosis per se-that are undetectable under light microscopy. One fertile mutant, phenotypically indistinguishable from the vacA group, has its vac mutation(s) restricted to the macronucleus, and it is a heterokaryon for two other markers. This clone probably resulted from a failure of the two gametic nuclei to fuse after normal exchange. Two additional mutants were studied, but their sterility prevented a full genetic analysis. One of these clones has a rudimentary oral apparatus and defective contractile vacuole pores; both defects may be determined by the same mutation. The other clone has a structurally normal oral apparatus and may be defective in phagocytosis per se.-The induction and characterization of germ-line mutations that affect oral development open the way for the genetic dissection of the morphogenesis of a complex eukaryotic organelle, and make available additional useful mutants for the study of nutrition and transmembrane active transport. PMID:17248939

  11. 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.

  12. 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.

  13. Virulence and potential pathogenicity of coccoid Helicobacter pylori induced by antibiotics

    PubMed Central

    She, Fei-Fei; Su, Dong-Hui; Lin, Jian-Yin; Zhou, Lin-Ying

    2001-01-01

    AIM: To explore the virulence and the potential pathogenicity of coccoid Helicobacter pylori (H. pylori) transformed from spiral form by exposure to antibiotic. METHODS: Three strains of H. pylori, isolated from gastric biopsy specimens of confirmed peptic ulcer, were converted from spiral into coccoid from by exposure to metronidazole. Both spiral and coccoid form of H. pylori were tested for the urease activity, the adherence to Hep 2 cells and the vacuolating cytotoxicity to Hela cells, and the differences of the protein were analysed by SDS-PAGE and Western blot. The mutation of the genes including ureA, ureB, hpaA, vacA and cagA, related with virulence, was detected by means of PCR and PCR-SSCP. RESULTS: In the coccoid H. pylori, the urease activity, the adherence to Hep 2 cells and the vacuolating cytotoxicity to Hela cells alldecreased. In strain F44, the rate and index of adherence reduced from 70.0% ± 5.3% to 33% ± 5.1% and from 2.6 ± 0.4 to 0.96 ± 0.3 (P < 0. 01), respectively. The invasion of coccoid H. pylori into Hep 2 cell could be seen under electronmicroscope. SDS-PAGE showed that the content of the protein with the molecular weight over Mr 74000 decreased, and the hybriditional signal in band Mr 125000 weakened, while the band Mr 110000 and Mr 63000 strengthened in coccoid H.pylori as shown in Western blot. The results of PCR were all positive, and PCR-SSCP indicated that there may exist the point mutation in gene hpaA or vacA. CONCLUSION: The virulence and the proteins with molecular weight over Mr 74000 in coccoid H.pylori decrease, but no deletion exists in amplification fragments from ureA, ureB, hpaA, vacA and cagA genes, suggesting that coccoid H.pylori may have potential pathogenicity. PMID:11819770

  14. Trazando el brazo de Vela-Puppis

    NASA Astrophysics Data System (ADS)

    Giorgi, E. E.; Vázquez, R. A.; Baume, G. L.; Seggewiss, W.; Feinstein, A.

    Presentamos resultados preliminares basados en análisis fotométricos UBVI para 9 cúmulos abiertos ubicados en la zona de Vela-Puppis (? =7h58m y 9h54m, ? =- 28o a -59o) sobre un total de 15 cúmulos previstos. Estos cúmulos no han sido observados previamente, excepto en algunos pocos casos que se cuenta con fotometría y espectroscospía de algunas estrellas. Se han determinado membrecias, excesos de color, distancias y edades. En el futuro, la muestra global permitirá definir mas claramente este brazo y será utilizada para estudiar las funciones iniciales de masa individuales e integradas y compararlas con las obtenidas en observaciones intensivas realizadas en otras zonas de la Galaxia.

  15. 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.

  16. In vitro and in vivo effects of apple peel polyphenols against Helicobacter pylori.

    PubMed

    Pastene, Edgar; Speisky, Hernán; García, Apolinaria; Moreno, Jessica; Troncoso, Miriam; Figueroa, Guillermo

    2010-06-23

    The inhibitory effects of a standarized apple peel polyphenol-rich extract (APPE) against Helicobacter pylori infection and vacuolating bacterial toxin (VacA) induced vacuolation were investigated. Apple peel polyphenols significantly prevented vacuolation in HeLa cells with an IC(50) value of 390 microg of gallic acid equivalents (GAE)/mL. APPE also displayed an in vitro antiadhesive effect against H. pylori. A significant inhibition was observed with a 20-60% reduction of H. pylori attachment at concentrations between 0.250 and 5 mg of GAE/mL. In a short-term infection model (C57BL6/J mice), two levels of APPE doses (150 and 300 mg/kg/day) showed an inhibitory effect on H. pylori attachment. Orally administered apple peel polyphenols also showed an anti-inflammatory effect on H. pylori-associated gastritis, lowering malondialdehyde levels and gastritis scores. PMID:20486708

  17. Hospital volunteer can't sue employer for botched HIV test.

    PubMed

    1996-11-29

    A California Court of Appeals affirmed a lower court ruling barring a hospital volunteer from bringing a medical malpractice suit against her employer, VacaValley Hospital. Volunteer [name removed] was injured as a result of an HIV antibody test. While blood was being drawn for the test, [name removed] suffered nerve damage to her right arm. She filed a claim for worker's compensation and sued the hospital for malpractice. A Circuit Court judge granted summary judgement that worker's compensation was [name removed]'s sole remedy under State law. The Court of Appeals agreed. [Name removed]'s HIV test was conducted following her on-the-job exposure to HIV and thus the procedures were provided as an employee health benefit available free of charge. In treating [name removed] was fulfilling its obligation under the protocol as her employer, not her health care provider. PMID:11364049

  18. 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.

  19. Helicobacter pylori cytotoxin: importance of native conformation for induction of neutralizing antibodies.

    PubMed Central

    Manetti, R; Massari, P; Burroni, D; de Bernard, M; Marchini, A; Olivieri, R; Papini, E; Montecucco, C; Rappuoli, R; Telford, J L

    1995-01-01

    We have attempted to express the Helicobacter pylori vacuolating cytotoxin in Escherichia coli. Although the 95-kDa VacA polypeptide was expressed abundantly, it completely lacked any biological activity. In addition, this material failed to induce neutralizing antibodies after immunization of rabbits. In contrast, highly purified high-molecular-mass cytotoxin from the supernatant of H. pylori cultures was active in a HeLa cell assay and effectively induced a neutralizing response in rabbits. Neutralizing sera were shown to contain a high proportion of antibodies which recognized conformational epitopes found only on the native toxin. The data indicate that toxin-neutralizing epitopes are conformational and that potential vaccines based on the cytotoxin may benefit from the use of the intact molecule. PMID:7591088

  20. A late Jurassic pterosaur (Reptilia, Pterodactyloidea) from northwestern Patagonia, Argentina

    NASA Astrophysics Data System (ADS)

    Codorniú, Laura; Gasparini, Zulma; Paulina-Carabajal, Ariana

    2006-03-01

    A small to medium-sized pterodactyloid pterosaur (wingspan approximately 1.10 m) from the Upper Jurassic (middle-late Tithonian) marine deposits of the Vaca Muerta Formation of Patagonia (Los Catutos area, central Neuquén Province, Argentina) is reported. The specimen lacks the skull but constitutes a nearly complete postcranial skeleton, which includes cervical and dorsal vertebrae; a few thoracic ribs; both pectoral girdles; the left pelvic girdle; a proximal right wing (humerus, ulna, and radius) and metacarpal IV; a left wing that lacks only wing phalanx four; and both hindlimbs, the right one without the foot. Ontogenetic features suggest that the new fossil corresponds to a relatively mature individual, probably a subadult. Observed characters support its assignment to the Archaeopteroactyloidea, a basal clade within the Pterodactyloidea. This specimen is the second pterosaur from Los Catutos and the most complete Jurassic pterosaur so far known from South America.

  1. Iron trafficking system in Helicobacter pylori.

    PubMed

    Ge, Ruiguang; Sun, Xuesong

    2012-04-01

    Helicobacter pylori infections are closely associated with peptic ulcers, gastric malignancy and iron deficiency anemia. Iron is essential for almost all living organisms and the investigation of iron uptake and trafficking system is thus important to understand the pathological roles of H. pylori. Up to now, the iron trafficking system of H. pylori is not yet fully clear and merits further efforts in this regards. The available information about iron uptake and regulation has been discussed in this concise review, such as FeoB in ferrous transportation, FrpB2 in hemoglobin uptake, HugZ in heme processing, virulence factors (VacA and CagA) in transferrin utilization, Pfr and NapA in iron storage and Fur in iron regulation. The identified iron trafficking system will help us to understand the pathological roles of H. pylori in the various gastric diseases and iron deficiency anemia and stimulates further development of effective anti-bacterial drugs. PMID:22127376

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

    TOXLINE Toxicology Bibliographic Information

    Meng W; Bai B; Sheng L; Li Y; Yue P; Li X; Qiao L

    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.

  3. Diet, microbial virulence, and Helicobacter pylori-induced gastric cancer

    PubMed Central

    Cover, Timothy L; Peek, Jr, Richard M

    2013-01-01

    Gastric adenocarcinoma is a leading cause of cancer-related death worldwide, and Helicobacter pylori infection is one of the strongest known risk factors for this malignancy. H. pylori strains exhibit a high level of genetic diversity, and the risk of gastric cancer is higher in persons carrying certain strain types (for example, those that contain a cag pathogenicity island or type s1 vacA alleles) than in persons carrying other strain types. Additional risk factors for gastric cancer include specific human genetic polymorphisms and specific dietary preferences (for example, a high-salt diet or a diet deficient in fruits and vegetables). Finally, iron-deficiency anemia is a risk factor for gastric cancer. Recent studies have provided evidence that several dietary risk factors for gastric cancer directly impact H. pylori virulence. In this review article, we discuss mechanisms by which diet can modulate H. pylori virulence and thereby influence gastric cancer risk. PMID:23989802

  4. Helicobacter pylori virulence factors in gastric carcinogenesis

    PubMed Central

    Wen, Sicheng; Moss, Steven F.

    2009-01-01

    Helicobacter pylori infection is the most important risk factor in the development of non-cardia gastric adenocarcinoma; host genetic variability and dietary co-factors also modulate risk. Because most H. pylori infections do not cause cancer, H. pylori heterogeneity has been investigated to identify possible virulence factors. The strongest candidates are genes within the cag (cytotoxin associated antigen) pathogenicity island, including the gene encoding the CagA protein, as well as polymorphic variation in the VacA vacuolating exotoxin and the blood group antigen binding adhesin BabA. Improved understanding of the pathogenesis of H. pylori-associated gastric cancer may improve risk stratification for prevention and therapy. PMID:19111390

  5. 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.

  6. 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?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

  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 eradication and H. pylori induced related gastric disease prevention. PMID:25132753

  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. 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.

  10. The Primary Resistance of Helicobacter pylori in Taiwan after the National Policy to Restrict Antibiotic Consumption and Its Relation to Virulence Factors—A Nationwide Study

    PubMed Central

    Chen, Mei-Jyh; Chen, Chieh-Chang; Fang, Yu-Jen; Lee, Ji-Yuh; Wu, Jeng-Yih; Luo, Jiing-Chyuan; Liou, Tai-Cherng; Chang, Wen-Hsiung; Tseng, Cheng-Hao; Wu, Chun-Ying; Yang, Tsung-Hua; Chang, Chun-Chao; Wang, Hsiu?Po; Sheu, Bor-Shyang; Lin, Jaw-Town; Bair, Ming-Jong; Wu, Ming-Shiang

    2015-01-01

    Objective The Taiwan Government issued a policy to restrict antimicrobial usage since 2001. We aimed to assess the changes in the antibiotic consumption and the primary resistance of H. pylori after this policy and the impact of virulence factors on resistance. Methods The defined daily dose (DDD) of antibiotics was analyzed using the Taiwan National Health Insurance (NHI) research database. H. pylori strains isolated from treatment naïve (N=1395) and failure from prior eradication therapies (N=360) from 9 hospitals between 2000 and 2012 were used for analysis. The minimum inhibitory concentration was determined by agar dilution test. Genotyping for CagA and VacA was determined by PCR method. Results The DDD per 1000 persons per day of macrolides reduced from 1.12 in 1997 to 0.19 in 2008, whereas that of fluoroquinolones increased from 0.12 in 1997 to 0.35 in 2008. The primary resistance of amoxicillin, clarithromycin, metronidazole, and tetracycline remained as low as 2.2%, 7.9%, 23.7%, and 1.9% respectively. However, the primary levofloxacin resistance rose from 4.9% in 2000–2007 to 8.3% in 2008–2010 and 13.4% in 2011–2012 (p=0.001). The primary resistance of metronidazole was higher in females than males (33.1% vs. 18.8%, p<0.001), which was probably attributed to the higher consumption of nitroimidazole. Neither CagA nor VacA was associated with antibiotic resistance. Conclusions The low primary clarithromycin and metronidazole resistance of H. pylori in Taiwan might be attributed to the reduced consumption of macrolides and nitroimidazole after the national policy to restrict antimicrobial usage. Yet, further strategies are needed to restrict the consumption of fluoroquinolones in the face of rising levofloxacin resistance. PMID:25942450

  11. Medicinal plant activity on Helicobacter pylori related diseases.

    PubMed

    Wang, Yuan-Chuen

    2014-08-14

    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-?B 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 eradication and H. pylori induced related gastric disease prevention. PMID:25132753

  12. Comparative Analysis of the Full Genome of Helicobacter pylori Isolate Sahul64 Identifies Genes of High Divergence

    PubMed Central

    Lu, Wei; Wise, Michael J.; Tay, Chin Yen; Windsor, Helen M.; Marshall, Barry J.; Peacock, Christopher

    2014-01-01

    Isolates of Helicobacter pylori can be classified phylogeographically. High genetic diversity and rapid microevolution are a hallmark of H. pylori genomes, a phenomenon that is proposed to play a functional role in persistence and colonization of diverse human populations. To provide further genomic evidence in the lineage of H. pylori and to further characterize diverse strains of this pathogen in different human populations, we report the finished genome sequence of Sahul64, an H. pylori strain isolated from an indigenous Australian. Our analysis identified genes that were highly divergent compared to the 38 publically available genomes, which include genes involved in the biosynthesis and modification of lipopolysaccharide, putative prophage genes, restriction modification components, and hypothetical genes. Furthermore, the virulence-associated vacA locus is a pseudogene and the cag pathogenicity island (cagPAI) is not present. However, the genome does contain a gene cluster associated with pathogenicity, including dupA. Our analysis found that with the addition of Sahul64 to the 38 genomes, the core genome content of H. pylori is reduced by approximately 14% (?170 genes) and the pan-genome has expanded from 2,070 to 2,238 genes. We have identified three putative horizontally acquired regions, including one that is likely to have been acquired from the closely related Helicobacter cetorum prior to speciation. Our results suggest that Sahul64, with the absence of cagPAI, highly divergent cell envelope proteins, and a predicted nontransportable VacA protein, could be more highly adapted to ancient indigenous Australian people but with lower virulence potential compared to other sequenced and cagPAI-positive H. pylori strains. PMID:24375107

  13. Effect of Helicobacter pylori Eradication on TLR2 and TLR4 Expression in Patients with Gastric Lesions

    PubMed Central

    Rossi, Ana Flávia Teixeira; Matos Biselli-Périco, Joice; Fucuta Pereira, Patrícia; Do Vale, Edla Polsinelli Bedin Mascarin; Acayaba, Ricardo; Leite, Kátia Ramos Moreira; Goloni-Bertollo, Eny Maria

    2015-01-01

    Objective. Helicobacter pylori (Hp) is recognized by TLR4 and TLR2 receptors, which trigger the activation of genes involved in the host immune response. Thus, we evaluated the effect of eradication therapy on TLR2 and TLR4 mRNA and protein expression in H. pylori-infected chronic gastritis patients (CG-Hp+) and 3 months after treatment. Methods. A total of 37 patients CG-Hp+ were evaluated. The relative quantification (RQ) of mRNA was assessed by TaqMan assay and protein expression by immunohistochemistry. Results. Before treatment both TLR2 and TLR4 mRNA in CG-Hp+ patients were slightly increased (TLR2 = 1.32; TLR4 = 1.26) in relation to Hp-negative normal gastric mucosa (P ? 0.05). After successful eradication therapy no significant change was observed (TLR2 = 1.47; TLR4 = 1.53; P > 0.05). In addition, the cagA and vacA bacterial genotypes did not influence the gene expression levels, and we observed a positive correlation between the RQ values of TLR2 and TLR4, both before and after treatment. Immunoexpression of the TLR2 and TLR4 proteins confirmed the gene expression results. Conclusion. In conclusion, the expression of both TLR2 and TLR4 is increased in CG-Hp+ patients regardless of cagA and vacA status and this expression pattern is not significantly changed after eradication of bacteria, at least for the short period of time evaluated. PMID:25873761

  14. The Costa Rican Central Valley Lavina Formation: Lahar or Debris Avalanche?

    NASA Astrophysics Data System (ADS)

    Hidalgo, P. J.; Alvarado Induni, G. E.; Linkimer, L.

    2005-12-01

    The Lavina Formation of the Central Valley of Costa Rica consists of lava blocks floating in a volcanic mud matrix. Different authors have interpreted this deposit genetically as a lahar or debris flow deposit. Based on geomorphologic, textural, and morphometric evidence, we conclude that the origin of this deposit is a debris avalanche event that transformed into a debris flow on its path down the valley. Using aerial photographs, many debris avalanche amphitheaters are found in the western sector of the Irazu volcanic complex. However, textural and morphometric characteristics of the deposit are consistent with the source of the sector collapse being located on the west flank of the Cabeza de Vaca volcano. Three-dimensional modeling of the Lavina Formation was done using data from 213 drill cores distributed along the Central Valley area. Maps of isopaches and isohipses of the roof and floor of this stratum were created. These allowed for qualification of morphometry of the stratigraphic surfaces, characterization of the paleoslopes, and quantification of the compacted deposit volume. The data derived form the isopach and isohipse contour maps indicate that abrupt changes in the thickness of the stratum are common. Also, it illustrates the morphological differences between the roof, elongated hills in the direction of the flux, and the floor of the stratum, smooth and uniform. The morphometric, geomorphologic, and textural evidence, were used to conclude that the Lavina deposit originated as a debris avalanche event in the Cabeza de Vaca Volcano. The debris avalanche was eventually fluidized into a debris flow that spread extensively (130 km2) along the Central Valley of Costa Rica.

  15. Comparative analysis of the full genome of Helicobacter pylori isolate Sahul64 identifies genes of high divergence.

    PubMed

    Lu, Wei; Wise, Michael J; Tay, Chin Yen; Windsor, Helen M; Marshall, Barry J; Peacock, Christopher; Perkins, Tim

    2014-03-01

    Isolates of Helicobacter pylori can be classified phylogeographically. High genetic diversity and rapid microevolution are a hallmark of H. pylori genomes, a phenomenon that is proposed to play a functional role in persistence and colonization of diverse human populations. To provide further genomic evidence in the lineage of H. pylori and to further characterize diverse strains of this pathogen in different human populations, we report the finished genome sequence of Sahul64, an H. pylori strain isolated from an indigenous Australian. Our analysis identified genes that were highly divergent compared to the 38 publically available genomes, which include genes involved in the biosynthesis and modification of lipopolysaccharide, putative prophage genes, restriction modification components, and hypothetical genes. Furthermore, the virulence-associated vacA locus is a pseudogene and the cag pathogenicity island (cagPAI) is not present. However, the genome does contain a gene cluster associated with pathogenicity, including dupA. Our analysis found that with the addition of Sahul64 to the 38 genomes, the core genome content of H. pylori is reduced by approximately 14% (?170 genes) and the pan-genome has expanded from 2,070 to 2,238 genes. We have identified three putative horizontally acquired regions, including one that is likely to have been acquired from the closely related Helicobacter cetorum prior to speciation. Our results suggest that Sahul64, with the absence of cagPAI, highly divergent cell envelope proteins, and a predicted nontransportable VacA protein, could be more highly adapted to ancient indigenous Australian people but with lower virulence potential compared to other sequenced and cagPAI-positive H. pylori strains. PMID:24375107

  16. Multiplex-PCR-Based Screening and Computational Modeling of Virulence Factors and T-Cell Mediated Immunity in Helicobacter pylori Infections for Accurate Clinical Diagnosis

    PubMed Central

    Oktem-Okullu, Sinem; Tiftikci, Arzu; Saruc, Murat; Cicek, Bahattin; Vardareli, Eser; Tozun, Nurdan; Kocagoz, Tanil; Sezerman, Ugur; Yavuz, Ahmet Sinan; Sayi-Yazgan, Ayca

    2015-01-01

    The outcome of H. pylori infection is closely related with bacteria's virulence factors and host immune response. The association between T cells and H. pylori infection has been identified, but the effects of the nine major H. pylori specific virulence factors; cagA, vacA, oipA, babA, hpaA, napA, dupA, ureA, ureB on T cell response in H. pylori infected patients have not been fully elucidated. We developed a multiplex- PCR assay to detect nine H. pylori virulence genes with in a three PCR reactions. Also, the expression levels of Th1, Th17 and Treg cell specific cytokines and transcription factors were detected by using qRT-PCR assays. Furthermore, a novel expert derived model is developed to identify set of factors and rules that can distinguish the ulcer patients from gastritis patients. Within all virulence factors that we tested, we identified a correlation between the presence of napA virulence gene and ulcer disease as a first data. Additionally, a positive correlation between the H. pylori dupA virulence factor and IFN-?, and H. pylori babA virulence factor and IL-17 was detected in gastritis and ulcer patients respectively. By using computer-based models, clinical outcomes of a patients infected with H. pylori can be predicted by screening the patient's H. pylori vacA m1/m2, ureA and cagA status and IFN-? (Th1), IL-17 (Th17), and FOXP3 (Treg) expression levels. Herein, we report, for the first time, the relationship between H. pylori virulence factors and host immune responses for diagnostic prediction of gastric diseases using computer—based models. PMID:26287606

  17. 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

  18. 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

  19. Host-Interactive Genes in Amerindian Helicobacter pylori Diverge from Their Old World Homologs and Mediate Inflammatory Responses? †

    PubMed Central

    Mane, S. P.; Dominguez-Bello, M. G.; Blaser, M. J.; Sobral, B. W.; Hontecillas, R.; Skoneczka, J.; Mohapatra, S. K.; Crasta, O. R.; Evans, C.; Modise, T.; Shallom, S.; Shukla, M.; Varon, C.; Mégraud, F.; Maldonado-Contreras, A. L.; Williams, K. P.; Bassaganya-Riera, J.

    2010-01-01

    Helicobacter pylori is the dominant member of the gastric microbiota and has been associated with an increased risk of gastric cancer and peptic ulcers in adults. H. pylori populations have migrated and diverged with human populations, and health effects vary. Here, we describe the whole genome of the cag-positive strain V225d, cultured from a Venezuelan Piaroa Amerindian subject. To gain insight into the evolution and host adaptation of this bacterium, we undertook comparative H. pylori genomic analyses. A robust multiprotein phylogenetic tree reflects the major human migration out of Africa, across Europe, through Asia, and into the New World, placing Amerindian H. pylori as a particularly close sister group to East Asian H. pylori. In contrast, phylogenetic analysis of the host-interactive genes vacA and cagA shows substantial divergence of Amerindian from Old World forms and indicates new genotypes (e.g., VacA m3) involving these loci. Despite deletions in CagA EPIYA and CRPIA domains, V225d stimulates interleukin-8 secretion and the hummingbird phenotype in AGS cells. However, following a 33-week passage in the mouse stomach, these phenotypes were lost in isolate V225-RE, which had a 15-kb deletion in the cag pathogenicity island that truncated CagA and eliminated some of the type IV secretion system genes. Thus, the unusual V225d cag architecture was fully functional via conserved elements, but the natural deletion of 13 cag pathogenicity island genes and the truncation of CagA impaired the ability to induce inflammation. PMID:20400544

  20. 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

  1. Loma La Lata giant gas field from a petroleum paleosystem, Neuquen Basin, Argentina

    SciTech Connect

    Guillermo, A.J.; Guillermo, A.L.

    1996-08-01

    The elements of a fully developed petroleum system may undergo later modifications, transforming it to a new system. We define the original system as a Petroleum Paleosystem. In the evolution of the Loma La Lata gas field, diagenetic processes have played a major role in the entrapment since reservoir, lateral and top seals consist of eolian sandstones. The gas origin can be explained as an early oil accumulation trapped between the Late Jurassic to Early Tertiary (petroleum paleosystem) that since Late Tertiary underwent a weak but sufficient thermal degradation to provoke the oil cracking resulting in the co-generation of wet gas+condensate+pyrobitumen-like residue. The elements of the paleosystem are: the Kimmeridgian eolian sandstones of the Sierras Blancas Formation+Catriel Formation as reservoir; the source rock and vertical seat is the rich organic matter marine shales associated with the 139 Ma MFS of the Vaca Muerta Formation; the lateral seal is the eolian facies of the Sierras Blancas Formation that experienced very early diagenesis under the strong influence of the phreatic oscillations in areas of maximum subsidence (Sauzal Bonito); the structural trap is related to the Cenomanian tectonic inversion phase; the expulsion peak was reached in the Late Eocene (40 Ma) and the migration from Vaca Muerta Formation. In the last 5 Ma the paleosystem was transformed by processes related to temperature increase. Subsequent calcite precipitation is extensive and resulted in the transformation of eolianites of the Catriel Formation in the vertical seal and coeval down dip remigration from the top of the structure. The intra-reservoir oil cracking has occurred as a consequence of an increment in the subsidence rate accompanied by an abnormally high geothermal gradient in the area.

  2. 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

  3. 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 264.7 coculture with that of H. pylori only. Some genes such as cagA, vacA, lpxC, murI, tlpC, trxB, sodB, tnpB, pgi, rbfA and infB showed a 2-20 fold upregulation. Statistically significant upregulation was obtained for all the above mentioned genes (P < 0.05). tlpC, cagA, vacA, sodB, rbfA, infB, tnpB, lpxC and murI were also significantly upregulated (P < 0.01). These data suggest a strong correlation between results obtained in vitro in the macrophage cell line and in the intact animal. CONCLUSION: The positive identification of these genes demonstrates that our IVET systems are powerful tools for studying H. pylori gene expression in the host environment. PMID:22969195

  4. 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 (tip?), 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). Conclusions These results demonstrate dramatic genome evolution within a species, especially in likely host interaction genes. The East Asian strains appear to differ greatly from the European strains in electron transfer and redox reactions. These findings also suggest a model of adaptive evolution through proteome diversification and selection through modulation of translational fidelity. The results define H. pylori East Asian lineages and provide essential information for understanding their pathogenesis and designing drugs and therapies that target them. PMID:21575176

  5. Helicobacter pylori outer membrane protein Q allele distribution is associated with distinct pathologies in Pakistan.

    PubMed

    Yakoob, Javed; Abbas, Zaigham; Khan, Rustam; Salim, Saima Azhar; Awan, Safia; Abrar, Ambar; Jafri, Wasim

    2016-01-01

    Helicobacter pylori (H. pylori) strains expressing outer membrane protein Q (HopQ) promote adherence to the gastric epithelial cell. We characterized HopQ alleles in relation to H. pylori-related disease, histology and virulence markers. Gastric biopsies were obtained at esophagogastroduodenoscopy from patients with upper gastrointestinal symptoms. H. pylori culture, histology and polymerase chain reaction (PCR) for HopQ types, cagA, cagA-promoter and vacA alleles were performed. DNA extracted was used for PCR. Sequencing of PCR products of HopQ types 1 and 2 was followed by BLAST query. We examined 241 H. pylori isolates. HopQ type 1 was positive in 70 (29%) isolates, type 2 in 60 (25%) isolates, while both type 1 and type 2 in 111 (46%) H. pylori isolates, respectively. Nonulcer dyspepsia (NUD) was associated with HopQ type 2 in 48 (41%) isolates, while gastric carcinoma (GC) in 37 (53%) (P<0.001) with type 1 isolates. Gastric ulcers (GU) were 39 (46%) (P<0.001) in H. pylori infection with multiple HopQ alleles compared to 6 (23%) in HopQ type 1. Multivariate analysis demonstrated that multiple HopQ alleles were associated with GU OR 2.9 (1.07-7.8) (P=0.03). HopQ type 1 was associated with cagA 58 (84%) (P<0.001) and cagA-promoter 58 (83%) (P<0.001) compared to 14 (23%) and 17 (28%) respectively, in type 2. VacAs1a was associated with HopQ type 1 in 59 (84%) isolates compared to HopQ type 2 in 35 (58%) (P=0.002) isolates. VacAm1 was associated with HopQ type 1 in 53 (76%) isolates compared to HopQ type 2 in 32 (53%) (P=0.004) isolates. H. pylori infection with multiple HopQ alleles was predominant. H. pylori infection with single HopQ type 1 was associated with GC in the presence of other H. pylori virulence markers. PMID:26516025

  6. Infection with CagA-positive Helicobacter pylori strain containing three EPIYA C phosphorylation sites is associated with more severe gastric lesions in experimentally infected Mongolian gerbils (Meriones unguiculatus).

    PubMed

    Ferreira Júnior, M; Batista, S A; Vidigal, P V T; Cordeiro, A A C; Oliveira, F M S; Prata, L O; Diniz, A E T; Barral, C M; Barbuto, R C; Gomes, A D; Araújo, I D; Queiroz, D M M; Caliari, M V

    2015-01-01

    Infection with Helicobacter pylori strains containing high number of EPIYA-C phosphorylation sites in the CagA is associated with significant gastritis and increased risk of developing pre-malignant gastric lesions and gastric carcinoma. However, these findings have not been reproduced in animal models yet. Therefore, we investigated the effect on the gastric mucosa of Mongolian gerbil (Meriones unguiculatus) infected with CagA-positive H. pylori strains exhibiting one or three EPIYA-C phosphorilation sites. Mongolian gerbils were inoculated with H. pylori clonal isolates containing one or three EPIYA-C phosphorylation sites. Control group was composed by uninfected animals challenged with Brucella broth alone. Gastric fragments were evaluated by the modified Sydney System and digital morphometry. Clonal relatedness between the isolates was considered by the identical RAPD-PCR profiles and sequencing of five housekeeping genes, vacA i/d region and of oipA. The other virulence markers were present in both isolates (vacA s1i1d1m1, iceA2, and intact dupA). CagA of both isolates was translocated and phosphorylated in AGS cells. After 45 days of infection, there was a significant increase in the number of inflammatory cells and in the area of the lamina propria in the infected animals, notably in those infected by the CagA-positive strain with three EPIYA-C phosphorylation sites. After six months of infection, a high number of EPIYA-C phosphorylation sites was associated with progressive increase in the intensity of gastritis and in the area of the lamina propria. Atrophy, intestinal metaplasia, and dysplasia were also observed more frequently in animals infected with the CagA-positive isolate with three EPIYA-C sites.  We conclude that infection with H. pylori strain carrying a high number of CagA EPIYA-C phosphorylation sites is associated with more severe gastric lesions in an animal model of H. pylori infection. PMID:26150158

  7. Instrumental Role of Helicobacter pylori γ-Glutamyl Transpeptidase in VacA-Dependent Vacuolation in Gastric Epithelial Cells

    PubMed Central

    Ling, Samantha Shi Min; Khoo, Lawrence Han Boon; Hwang, Le-Ann; Yeoh, Khay Guan; Ho, Bow

    2015-01-01

    Helicobacter pylori causes cellular vacuolation in host cells, a cytotoxic event attributed to vacuolating cytotoxin (VacA) and the presence of permeant weak bases such as ammonia. We report here the role of γ-glutamyl transpeptidase (GGT), a constitutively expressed secretory enzyme of H. pylori, in potentiating VacA-dependent vacuolation formation in H. pylori-infected AGS and primary gastric cells. The enhancement is brought about by GGT hydrolysing glutamine present in the extracellular medium, thereby releasing ammonia which accentuates the VacA-induced vacuolation. The events of vacuolation in H. pylori wild type (WT)- and Δggt-infected AGS cells were first captured and visualized by real-time phase-contrast microscopy where WT was observed to induce more vacuoles than Δggt. By using semi-quantitative neutral red uptake assay, we next showed that Δggt induced significantly less vacuolation in AGS and primary gastric epithelial cells as compared to the parental strain (P<0.05) indicating that GGT potentiates the vacuolating effect of VacA. Notably, vacuolation induced by WT was significantly reduced in the absence of GGT substrate, glutamine (P<0.05) or in the presence of a competitive GGT inhibitor, serine-borate complex. Furthermore, the vacuolating ability of Δggt was markedly restored when co-incubated with purified recombinant GGT (rGGT), although rGGT itself did not induce vacuolation independently. Similarly, the addition of exogenous ammonium chloride as a source of ammonia also rescued the ability of Δggt to induce vacuolation. Additionally, we also show that monoclonal antibodies against GGT effectively inhibited GGT activity and successfully suppressed H. pylori-induced vacuolation. Collectively, our results clearly demonstrate that generation of ammonia by GGT through glutamine hydrolysis is responsible for enhancing VacA-dependent vacuolation. Our findings provide a new perspective on GGT as an important virulence factor and a promising target in the management of H. pylori-associated gastric diseases. PMID:26111186

  8. Genotypic and clinical differences of seropositive Helicobacter pylori children and adults in the Polish population.

    PubMed

    Iwanczak, B; Laszewicz, W; Iwanczak, F; Dzierzanowska-Fangrat, K; Rozynek, M; Dzierzanowska, D; Gosciniak, G; Dlugosz, J

    2014-12-01

    Helicobacter pylori (H. pylori) plays an important role in the pathogenesis of the upper gastrointestinal tract diseases in both children and adults. The aim of this paper was to assess the differences between the clinical course of the disease in children and adults. This paper also presents an analysis of clinical symptoms, endoscopic and histopathological findings, H. Pylori cagA and vacA genotypes rates and analysis of the sensitivity of these strains to antibiotics in the Polish population, with possible practical and therapeutic implications. The multicenter study on the frequency of H. pylori infections assessed by the presence of antibodies in IgG class against H. pylori in serum was conducted in the years 2002 and 2003. The study group included 6565 children and adults, in 3827 of whom antibodies levels were above 24 U/mL. The authors analyzed clinical and endoscopic symptoms and in some patients with H. pylori seropositivity also histopathological changes, and cagA and vacA genes. Sensitivity of H. pylori strains to antibiotics were also analyzed. Differences between the frequency of infection between children and adults were determined. Endoscopic examination in adults revealed more frequent cases of gastropathy (P=0.003) and erosive gastritis (P=0.001), and in children-thick mucosal folds (P<0.0001). Histopathological examinations carried out in adults have revealed atrophic gastritis and intestinal metaplasia. In children, cagA(+) s1m1 was observed more frequently than in adults (34.0% versus 23.1%; P=0.02) contrary to cagA(-)s2m2 which occurred more frequently in adults (27.1% versus 14.0%; P=0.003). No effect of the infection on nausea, regurgitation, vomiting, heartburn, and abdominal pain in children was detected. However, adults infected with H. pylori suffered from more frequent episodes of heartburn and abdominal pain. The H. pylori strain exhibited a high resistance to metronidazole (higher in adults: 41.7% versus 27.4%; P=0.002), and to clarithromycin (higher in children: 20.2% versus 15.4%; P>0.05), and dual resistance to metronidazole and clarithromycin (higher in children: 9.9% versus 8.4%; P>0.05). Resistance of the H. pylori to amoxicillin and tetracycline was not detected. The conducted study indicated clinical differences in the H. pylori infection in children and adults. Among the differences in children, especially the more frequent infections by the cagA(+)s1m1/m2 strain could have an influence on further consequences of the infection. The obtained results could be useful in therapeutic decisions. PMID:25554984

  9. Infection with CagA-Positive Helicobacter Pylori Strain Containing Three EPIYA C Phosphorylation Sites is Associated with More Severe Gastric Lesions in Experimentally Infected Mongolian Gerbils (Meriones Unguiculatus)

    PubMed Central

    Junior, M. Ferreira; Batista, S.A.; Vidigal, P.V.T; Cordeiro, A.A.C.; Oliveira, F.M.S.; Prata, L.O.; Diniz, A.E.T.; Barral, C.M.; Barbuto, R.C.; Comes, A.D.; Araujo, I.D.; Queiroz, D.M.M.; Caliari, M.V.

    2015-01-01

    Infection with Helicobacter pylori strains containing high number of EPIYA-C phosphorylation sites in the CagA is associated with significant gastritis and increased risk of developing pre-malignant gastric lesions and gastric carcinoma. However, these findings have not been reproduced in animal models yet. Therefore, we investigated the effect on the gastric mucosa of Mongolian gerbil (Meriones unguiculatus) infected with CagA-positive H. pylori strains exhibiting one or three EPIYA-C phosphorilation sites. Mongolian gerbils were inoculated with H. pylori clonal isolates containing one or three EPIYA-C phosphorylation sites. Control group was composed by uninfected animals challenged with Brucella broth alone. Gastric fragments were evaluated by the modified Sydney System and digital morphometry. Clonal relatedness between the isolates was considered by the identical RAPD-PCR profiles and sequencing of five housekeeping genes, vacA i/d region and of oipA. The other virulence markers were present in both isolates (vacA s1i1d1m1, iceA2, and intact dupA). CagA of both isolates was translocated and phosphorylated in AGS cells. After 45 days of infection, there was a significant increase in the number of inflammatory cells and in the area of the lamina propria in the infected animals, notably in those infected by the CagA-positive strain with three EPIYA-C phosphorylation sites. After six months of infection, a high number of EPIYA-C phosphorylation sites was associated with progressive increase in the intensity of gastritis and in the area of the lamina propria. Atrophy, intestinal metaplasia, and dysplasia were also observed more frequently in animals infected with the CagA-positive isolate with three EPIYA-C sites. We conclude that infection with H. pylori strain carrying a high number of CagA EPIYA-C phosphorylation sites is associated with more severe gastric lesions in an animal model of H. pylori infection. PMID:26150158

  10. 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 attitudes toward geoscience after having participated in laboratory activities and Family Science Nights. Preliminary findings on the extent to which geoscience and geoscience careers become part of families' purviews, discourses and planning through involvement in Family Science Nights will be presented. Implications related to the success of this program, as indicated by measurement of students' knowledge and attitudes of geoscience as well as engagement of this program by families, will be discussed.

  11. 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 geochemically of low grade. In contrast, a large crosscutting bitumen dyke is of higher grade and formed later. At other localities, near basement faults, bitumen dykes have cap-rocks of hydrothermal calcrete. Other dykes or their wall rocks contain hydrothermal minerals. Finally, some dykes splay upward towards the current land surface. We conclude that (1) the bitumen dykes formed during volcanic activity in Pliocene-Pleistocene times, and that (2) heat advection by hydrothermal fluids helped to generate oil, which migrated upwards or downwards from the source rock and filled intrusive veins, before solidifying to bitumen, by loss of volatile elements. This unconventional hydrocarbon system may have significant implications for regional exploration in the foothills of the Andes.

  12. 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 :

  13. 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.

  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. Fotometría superficial de la galaxia irregular NGC 1427A

    NASA Astrophysics Data System (ADS)

    Cellone, S. A.; Forte, J. C.

    Se presenta fotometría superficial multicolor de la galaxia irregular NGC 1427A. Esta galaxia, un miembro del Cúmulo de Fornax que no ha sido estudiado previamente, muestra una morfología muy particular: una distribución estelar subyacente de bajo brillo superficial (LSB) con varias manchas brillantes dispuestas en una estructura anular deformada. Por sus colores muy azules se infiere que estas son zonas de formación estelar reciente. Al norte del cuerpo principal de la galaxia, y conectado con éste mediante filamentos LSB, hay un objeto de isofotas aproximadamente circulares. Este objeto tiene en sí mismo algunas zonas brillantes, pero su población estelar subyacente es significativamente más azul que la del cuerpo principal de la galaxia. Esto indica que ambos objetos han tenido distintas historias evolutivas. Estructuralmente, el objeto del norte es muy similar a algunas de las galaxias elípticas enanas más débiles que pueblan el Cúmulo de Fornax. Se discute la posible relación entre este objeto y la galaxia en si.

  16. 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

  17. 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

  18. Signal transduction of Helicobacter pylori during interaction with host cell protein receptors of epithelial and immune cells.

    PubMed

    Pachathundikandi, Suneesh Kumar; Tegtmeyer, Nicole; Backert, Steffen

    2013-01-01

    Helicobacter pylori infections can induce pathologies ranging from chronic gastritis, peptic ulceration to gastric cancer. Bacterial isolates harbor numerous well-known adhesins, vacuolating cytotoxin VacA, protease HtrA, urease, peptidoglycan, and type IV secretion systems (T4SS). It appears that H. pylori targets more than 40 known host protein receptors on epithelial or immune cells. A series of T4SS components such as CagL, CagI, CagY, and CagA can bind to the integrin ? 5? 1 receptor. Other targeted membrane-based receptors include the integrins ?v? 3, ?v? 5, and ? 2 (CD18), RPTP-?/?, GP130, E-cadherin, fibronectin, laminin, CD46, CD74, ICAM1/LFA1, T-cell receptor, Toll-like receptors, and receptor tyrosine kinases EGFR, ErbB2, ErbB3, and c-Met. In addition, H. pylori is able to activate the intracellular receptors NOD1, NOD2, and NLRP3 with important roles in innate immunity. Here we review the interplay of various bacterial factors with host protein receptors. The contribution of these interactions to signal transduction and pathogenesis is discussed. PMID:24280762

  19. 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, tnf?, 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

  20. Pathogenesis of Helicobacter pylori Infection

    PubMed Central

    Kusters, Johannes G.; van Vliet, Arnoud H. M.; Kuipers, Ernst J.

    2006-01-01

    Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori. PMID:16847081

  1. 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.

  2. Antibacterial activities of almond skins on cagA-positive and-negative clinical isolates of Helicobacter pylori

    PubMed Central

    2013-01-01

    Background Helicobacter pylori is known to be a gastric pathogen of humans. Eradication regimens for H. pylori infection have some side effects, compliance problems, relapses, and antibiotic resistance. Therefore, the need for alternative therapies for H. pylori infections is of special interest. We have previously shown that polyphenols from almond skins are active against a range of food-borne pathogens. The aim of this study was to evaluate the antibacterial effects of natural almond skins before and after simulated human digestion and the pure flavonoid compounds epicatechin, naringenin and protocatechuic acid against H. pylori. Results H. pylori strains were isolated from gastric biopsy samples following standard microbiology procedures. Also, cagA and vacA genes were identified using PCR. Susceptibility studies on 34 strains of H. pylori, including two reference strains (ATCC 43504, ATCC 49503), were performed by the standard agar dilution method. Natural almond skin was the most effective compound against H. pylori (MIC range, 64 to 128 ?g/ml), followed by natural skin post gastric digestion (MIC range, 128 to 512 ?g/ml), and natural almond skin post gastric plus duodenal digestion (MIC range, 256 to 512 ?g/ml). Amongst the pure flavonoid compounds, protocatechuic acid showed the greatest activity (MIC range, 128 to 512 ?g/ml) against H. pylori strains. Conclusions Polyphenols from almond skins were effective in vitro against H. pylori, irrespective of genotype status and could therefore be used in combination with antibiotics as a novel strategy for antibiotic resistance. PMID:23659287

  3. 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

  4. 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

  5. Helicobacter pylori induces apoptosis of T- and B-cell lines and translocates mitochondrial apoptosis-inducing factor to nucleus.

    PubMed

    Singh, Manisha; Prasad, Kashi N; Saxena, Ashish; Yachha, Surender K

    2006-04-01

    Immune cell apoptosis may play a role in human persistent Helicobacter pylori infection. We planned to study the apoptosis of T and B cells by H. pylori strains. T (Jurkat) and B (Raji) cell lines were co-cultured with cagA-positive H. pylori strains carrying different vacA genotypes (s1a/m1, s1a/m2, and s2/m2). Apoptosis was detected by microscopy, DNA fragmentation assay, and flow cytometry. Apoptosis-inducing factor (AIF) transfer from mitochondria to nucleus was studied by immunoblot analysis. Apoptosis of T and B cells was significantly higher in H. pylori-infected cells than in uninfected controls (s1a/m1 80%, s1a/m2 78%, s2m2 69% vs. control 16% for T cells, P < 0.001; s1 a/m1 78%, s1a/m2 73%, s2m2 62% vs. control 24% for B cells, P < 0.001 by flow cytometry) with no difference among the genotypes. AIF transfer from mitochondria to nucleus was demonstrated in both apoptotic cell lines. Thus, H. pylori induces apoptosis in T- and B-cell lines and translocates AIF. T and B cells deletion through apoptosis may explain the persistence of H. pylori infection; its role in pathogenesis needs further research. PMID:16528467

  6. 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

  7. 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.

  8. Helicobacter pylori: correlation of the virulence marker iceA allele with clinical outcome in a high prevalence area.

    PubMed

    Yakoob, J; Abbas, Z; Khan, R; Salim, S A; Abrar, A; Awan, S; Ahmad, Z

    2015-01-01

    The association of Helicobacter pylori virulence marker 'induced by contact with epithelium A' (iceA) allele types was determined in H. pylori-related diseases and virulence markers. Gastric biopsies were obtained at EGD from patients for culture, histopathology and polymerase chain reaction (PCR) for iceA types, cagA and vacA alleles. Two hundred and eighty-four H. pylori isolates were examined. iceA type 1 was positive in 177 (62%) and iceA type 2 in 158 (56%). In iceA type 2, gastric ulcer was present in 34 (21%) (P < 0.001) and carcinoma in 28 (25%) (P = 0.002), compared to nine (8%) and 2 (2%) in iceA type 2-negative cases. For iceA type 2, 139 (88%) were associated with chronic active gastritis compared to 95 (75%) (P = 0.006) in iceA type 2-negative. H. pylori cagA was positive in 101 (64%) iceA type 2 strains compared to 57 (45%) in negative strains (P = 0.002). H. pylori iceA type 2 was dominant and associated with cagA, chronic active inflammation, gastric ulcer and carcinoma. PMID:26126322

  9. Fine resolution chronology based on initial Sr-87/Sr-86

    NASA Technical Reports Server (NTRS)

    Stewart, B. W.; Papanastassiou, D. A.; Capo, R. C.; Wasserburg, G. J.

    1993-01-01

    It has been recognized that small variations in initial Sr-87/Sr-86 (Sr(sub I)), can provide a fine scale relative chronology for the chemical fractionation of materials with low Rb/Sr from parent reservoirs with high Rb/Sr. Similarly, Sr(sub I), as determined for low Rb/Sr phases in meteorites, may permit a fine resolution chronology of the recrystallization or metamorphism of planetary materials. For the establishment of a primitive Sr-87/Sr-86 chronology, it is important to search for samples with extremely low Rb/Sr for which the measured Sr-87/Sr-86 is below BABI, in which case the primitive nature of the Sr can be directly established. Using the measured Rb/Sr to calculate an initial Sr-87/Sr-86 can introduce substantial uncertainty if the Rb-Sr are disturbed. We report Sr-87/Sr-86 in plagioclase from silicate pebbles from the Vaca Muerta mesosiderite on which we have reported Sm-147-Nd-143 and Ne-142 correlations. For the purpose of cross-calibration with our previous work we have performed extensive new measurements on Angra dos Reis and on anorthite from Moore County, which have very low Rb/Sr and primitive Sr-87/Sr-86.

  10. The functional interplay of Helicobacter pylori factors with gastric epithelial cells induces a multi-step process in pathogenesis

    PubMed Central

    2013-01-01

    Infections with the human pathogen Helicobacter pylori (H. pylori) can lead to severe gastric diseases ranging from chronic gastritis and ulceration to neoplastic changes in the stomach. Development and progress of H. pylori-associated disorders are determined by multifarious bacterial factors. Many of them interact directly with host cells or require specific receptors, while others enter the host cytoplasm to derail cellular functions. Several adhesins (e.g. BabA, SabA, AlpA/B, or OipA) establish close contact with the gastric epithelium as an important first step in persistent colonization. Soluble H. pylori factors (e.g. urease, VacA, or HtrA) have been suggested to alter cell survival and intercellular adhesions. Via a type IV secretion system (T4SS), H. pylori also translocates the effector cytotoxin-associated gene A (CagA) and peptidoglycan directly into the host cytoplasm, where cancer- and inflammation-associated signal transduction pathways can be deregulated. Through these manifold possibilities of interaction with host cells, H. pylori interferes with the complex signal transduction networks in its host and mediates a multi-step pathogenesis. PMID:24099599

  11. Identification of cagA tyrosine phosphorylation DNA motifs in Helicobacter pylori isolates from peptic ulcer patients by novel PCR-restriction fragment length polymorphism and real-time fluorescence PCR assays.

    PubMed

    Owen, Robert J; Sharp, Sally I; Chisholm, Stephanie A; Rijpkema, Sjoerd

    2003-07-01

    Cag pathogenicity island-containing Helicobacter pylori (type I) induces signal transduction pathways resulting in tyrosine phosphorylation of proteins adjacent to the site of bacterial adhesion on host gastric epithelial cells. Conventional block PCR-restriction fragment length polymorphism (RFLP) and real-time LightCycler (LC) PCR hybridization assays, validated by direct sequencing, were designed to test for the presence of three nucleotide sequences corresponding to tyrosine phosphorylation motifs (TPMs) A, B, and C in 84 isolates of H. pylori type I from patients in England. Overall, the PCR assays demonstrated that one or more TPMs were present in 62 strains (75%). Motif A was common (71% of strains), whereas motifs B and C were rarer (8% of strains). Strains lacking a TPM were typically vacuolating cytotoxin genotype vacA m2. Motif A was widely distributed in relation to disease severity and was more commonly (but not significantly [P = 0.071]) associated with gastric ulcer than with duodenal ulcer (86 versus 56%). The LC hybridization assay provided a rapid means of detecting all three motifs, but RFLP analysis was more specific for TPM-A. TPMs provide novel additional strain markers for defining cagA variation, including identification of RFLP types within TPM-A. The presence of a particular TPM was not of direct diagnostic value, either singly or in combination, but the higher proportion of TPM-A strains in gastric ulcer patients merits further investigation. PMID:12843050

  12. Multiple Infection and Microdiversity among Helicobacter pylori Isolates in a Single Host in India

    PubMed Central

    Patra, Rajashree; Chattopadhyay, Santanu; De, Ronita; Ghosh, Prachetash; Ganguly, Mou; Chowdhury, Abhijit; Ramamurthy, T.; Nair, G. B.; Mukhopadhyay, Asish K.

    2012-01-01

    Helicobacter pylori is one of the most diverse bacterial species that chronically infects more than 70% of Indian population. Interestingly, data showing microdiversity of the H. pylori strains within a particular gastric niche remained scarce. To understand the extent of genetic diversity among H. pylori strains within a given host, 30 patients with gastro-duodenal problems were subjected to endoscopy and from each patient 10 single colonies were isolated. Characterization of each of these 10 single colonies by DNA fingerprinting as well as genotyping of several important genetic markers viz. cagA, vacA, iceA, vapD, cag PAI empty site, IS605, RFLP and two other genetic segments within cag PAI revealed that all of the 30 patients were infected with more than one strain and sometimes strains with 5 to 6 types of genetic variants. Analyses of certain genetic loci showed the microdiversity among the colonies from single patient, which may be due to the recombination events during long-term carriage of the pathogen. These results suggest that most of the patients have acquired H. pylori due to repeated exposure to this pathogen with different genetic make-up, which may increase the possibility of super infections. Genetic exchanges between these unrelated H. pylori strains may support certain H. pylori variant to grow better in a given host than the parental strain and thereby increasing the possibility for the severity of the infection. PMID:22952670

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

    PubMed Central

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

    2014-01-01

    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

  14. Helicobacter pylori Activates Calpain via Toll-Like Receptor 2 To Disrupt Adherens Junctions in Human Gastric Epithelial Cells ?

    PubMed Central

    O'Connor, Pamela M.; Lapointe, Tamia K.; Jackson, Shannon; Beck, Paul L.; Jones, Nicola L.; Buret, Andre G.

    2011-01-01

    Helicobacter pylori is a risk factor for the development of gastritis, gastroduodenal ulcers, and gastric adenocarcinoma. H. pylori-induced disruption of epithelial adherens junctions (AJs) is thought to promote the development of severe disease; however, the mechanisms whereby H. pylori alters AJ structure remain incompletely understood. The present study demonstrates that H. pylori infection in human patients is associated with elevated serum levels of an 80-kDa E-cadherin ectodomain, whose presence is independent of the presence of serum antibodies against CagA. In vitro, a heat-labile H. pylori surface component activates the host protease calpain in human gastric MKN45 cells independently of the virulence factors CagA and VacA. H. pylori-induced calpain activation results in cleavage of E-cadherin to produce a 100-kDa truncated form and induce relocalization of E-cadherin and ?-catenin. Stimulation of MKN45 cells with the toll-like receptor 2 (TLR2) ligand P3C activated calpain and disrupted E-cadherin and ?-catenin in a pattern similar to that induced by H. pylori. Inhibition of TLR2 prevented H. pylori-induced calpain activation and AJ disassembly. Together, these findings identify a novel pathway whereby H. pylori activates calpain via TLR2 to disrupt gastric epithelial AJ structure. PMID:21825064

  15. Exclusive measurements of pion nucleon going to pion pion nucleon

    NASA Astrophysics Data System (ADS)

    Kermani, Mohammad Arjomand

    The pion induced pion production reactions ?±p/to?±?+n were studied at projectile incident energies of 223, 243, 264, 284, and 305 MeV. The Canadian High Acceptance Orbit Spectrometer (CHAOS) was used to detected the charged particles, which originated from the interaction of the incident pion beam with a cryogenic liquid hydrogen target. The experimental results are presented in the form of single, double and triple differential cross sections. Total cross sections obtained by integrating the differential quantities are also reported. The experimental data, namely the ?-p/to?-?+n double differential cross sections, were used as input to the Chew-Low extrapolation procedure which was utilized to determine on-shell ?+?- elastic scattering cross sections in the near threshold region. The Chew-Low results (the extrapolated ?pi cross sections) were then used in a dispersion analysis (Roy equations) to obtain the ?pi isospin zero S-wave scattering length. We find a00=0.209/pm 0.011?-1. In addition, the invariant mass distributions from the (?+?-) channel were fitted to determine the model parameters for the extended model of Oset and Vicente-Vacas. We find that the model parameters obtained from fitting the (?+?-) data do not describe the invariant mass distributions in the (?+?+) channel.

  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. 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

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. Signal transduction of Helicobacter pylori during interaction with host cell protein receptors of epithelial and immune cells

    PubMed Central

    Pachathundikandi, Suneesh Kumar; Tegtmeyer, Nicole; Backert, Steffen

    2013-01-01

    Helicobacter pylori infections can induce pathologies ranging from chronic gastritis, peptic ulceration to gastric cancer. Bacterial isolates harbor numerous well-known adhesins, vacuolating cytotoxin VacA, protease HtrA, urease, peptidoglycan, and type IV secretion systems (T4SS). It appears that H. pylori targets more than 40 known host protein receptors on epithelial or immune cells. A series of T4SS components such as CagL, CagI, CagY, and CagA can bind to the integrin α5β1 receptor. Other targeted membrane-based receptors include the integrins αvβ3, αvβ5, and β2 (CD18), RPTP-α/β, GP130, E-cadherin, fibronectin, laminin, CD46, CD74, ICAM1/LFA1, T-cell receptor, Toll-like receptors, and receptor tyrosine kinases EGFR, ErbB2, ErbB3, and c-Met. In addition, H. pylori is able to activate the intracellular receptors NOD1, NOD2, and NLRP3 with important roles in innate immunity. Here we review the interplay of various bacterial factors with host protein receptors. The contribution of these interactions to signal transduction and pathogenesis is discussed. PMID:24280762

  5. 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

  6. Analysis on the mechanism of Helicobacter pylori-induced apoptosis in gastric cancer cell line BGC-823.

    PubMed

    Chen, Yongchang; Wang, Ying; Xu, Wenrong; Zhang, Zhijian

    2005-10-01

    Helicobacter pylori (Hp) can induce apoptosis of gastric cancer cells. The mechanism of the process still needs further elucidating. This study was aimed to analyse the mechanism through which Hp induce apoptosis in human gastric cancer cell line BGC-823. The extract from VacA(+) and CagA(+) Helicobacter pylori strain NCTC11637 was applied to induce apoptosis. The expression, breakdown, and phosphorylation of proteins were probed by Western blotting with specific antibodies. Apoptosis of the cells was detected by flow cytometry. The results showed that incubating the cells with Hp extract caused the breakdown of both caspase-3 and -1. The breakdown was dose-dependent and correlated with the occurrence of the Hp extract-induced apoptosis. Among the substrates of caspase-3, DNA fragment factor (DFF) was degraded during incubation with Hp extract and a small fragment was released. However, poly(ADP-ribose) polymerase (PARP) did not break down during the incubation. Tyrosine kinase inhibitor Genistein prevented both the break down of caspase-3 and the apoptosis induced by Hp extract. MAPK/ERK inhibitor PD98059 did not prevent the apoptosis induced by Hp extract. The expression and activity of JNK, and the expression of Bcl-2 and Fas proteins did not change during the incubation with Hp extract. The results suggested that Hp extract initiated apoptosis in BGC-823 cells through activating tyrosine kinase, caspase-1, -3, and DFF. PMID:16142414

  7. Diphenyleneiodonium Inhibits Apoptotic Cell Death of Gastric Epithelial Cells Infected with Helicobacter pylori in a Korean Isolate

    PubMed Central

    Cho, Soon Ok; Lim, Joo Weon

    2015-01-01

    NADPH oxidase produces a large amount of reactive oxygen species (ROS) in Helicobacter pylori (H. pylori)-induced gastric epithelial cells. Even though ROS mediate apoptotic cell death, direct involvement of NADPH oxidase on H. pylori-induced apoptosis remains unclear. Besides, H. pylori isolates show a high degree of genetic variability. The predominant genotype of H. pylori in Korea has been reported as cagA+, vacA s1b, m2, iceA genotype. Present study aims to investigate whether NADPH oxidase-generated ROS mediate apoptosis in human gastric epithelial AGS cells infected with H. pylori in a Korean isolate. AGS cells were pretreated with or without an NADPH oxidase inhibitor diphenyleneiodonium (DPI) and cultured in the presence of H. pylori at a bacterium/cell ratio of 300:1. Cell viability, hydrogen peroxide level, DNA fragmentation, and protein levels of p53, Bcl-2, and Bax were determined. Results showed that H. pylori inhibited cell viability with the density of H. pylori added to the cells. Inhibition of NADPH oxidase by DPI suppressed H. pylori-induced cell death, increased hydrogen peroxide, DNA fragmentation, and the ratio of Bax/Bcl-2, and p53 induction in AGS cells dose-dependently. The results suggest that targeting NADPH oxidase may prevent the development of gastric inflammation associated with H. pylori infection by suppressing abnormal apoptotic cell death of gastric epithelial cells. PMID:26069142

  8. Correlation Between Mucosal IL-6 mRNA Expression Level and Virulence Factors of Helicobacter pylori in Iranian Adult Patients With Chronic Gastritis

    PubMed Central

    Azadegan-Dehkordi, Fatemeh; Bagheri, Nader; Shirzad, Mahsa; Sanei, Mohammad Hossein; Hashemzadeh-Chaleshtori, Morteza; Rafieian-Kopaei, Mahmoud; Tabatabaiefar, Mohammad Amin; Shirzad, Hedayatollah

    2015-01-01

    Background: Helicobacter pylori infection is associated with gastritis and marked infiltration of the gastric mucosa by several cytokines secreting inflammatory cells that contribute to sustained local inflammation. In this study, we sought to examine IL-6 expression in H. pylori-infected and uninfected gastric mucosa and elucidate the implication in the pathogenesis of H. pylori-associated gastritis in human. Objectives: The current study aimed to determine mucosal IL-6 mRNA expression level and their correlation with virulence factors and the grade of chronic gastritis among H. pylori infected patients with chronic gastritis from Shahrekord, Iran. Patients and Methods: Mucosal IL-6 mRNA levels was measured by real-time PCR using endoscopic biopsies taken from the gastric antrum of 58 subjects infected with H. pylori and 44 uninfected subjects. Presence of vacA and cagA virulence factors was evaluated using PCR. Results: The IL-6 mRNA expression levels were significantly more elevated in H. pylori-positive patients than uninfected individuals and expression of this cytokine was independent from the virulence factors. There was a correlation between IL-6 expression level and the grade of chronic gastritis. Conclusions: Enhanced induction of IL-6 may be involved in the pathogenesis of H. pylori-associated gastritis. PMID:26464767

  9. Helicobacter pylori in Vegetables and Salads: Genotyping and Antimicrobial Resistance Properties

    PubMed Central

    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

  10. 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:22039453

  11. 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.

  12. Recombinant human lactoferrin enhances the efficacy of triple therapy in mice infected with Helicobacter pylori

    PubMed Central

    YUAN, YUPING; WU, QINYI; CHENG, GUOXIANG; LIU, XUEFANG; LIU, SIGUO; LUO, JUAN; ZHANG, AIMIN; BIAN, LI; CHEN, JIANQUAN; LV, JIAJUN; DONG, XIANGQIAN; YANG, GANG; ZHU, YUNZHEN; MA, LANQING

    2015-01-01

    Helicobacter pylori (H. pylori) is a life-threatening pathogen which causes chronic gastritis, gastric ulcers and even stomach cancer. Treatment normally involves bacterial eradication; however, this type of treatment only has a rate of effectiveness of <80%. Thus, it is a matter of some urgency to develop new therapeutic strategies. Lactoferrin, a member of the transferrin family of iron-binding proteins, has been proven to be effective in removing a vast range of pathogens, including H. pylori. In the present study, we examined the effectiveness of recombinant human lactoferrin (rhLf) isolated from transgenic goats as a treatment for H. pylori in vitro and in vivo. For the in vivo experiments, BALB/c mice received an intragastric administration of 0.1 ml of a suspension of H. pylori. The mice were then divided into 4 groups: group A, treated with saline; group B, treated with 1.5 g of rhLF; group C, treated with the standard triple therapy regimen; and group D, treated with the standard triple therapy regimen plus.5 g of rhLF. Following sacrifice, the stomach tissues of the mice were histologically examined for the presence of bacteria. For the in vitro experiments, the bacteria were cultured in BHI broth and RT-qPCR and western blot analysis were carried out to determine the mRNA and protein levels of virulence factors (CagA and VacA) in the cultures. Our results revealed that rhLf not only inhibited the growth of H. pylori, but also suppressed the expression of two major virulence factors. Moreover, rhLf markedly increased bacterial eradication and effectively reduced the inflammatory response when combined with the standard triple therapy regimen. These results provide evidence supporting the use of rhLF as an adjuvant to traditional therapeutic strategies in the treatment of H. pylori. PMID:26080893

  13. Helicobacter pylori-induced histone modification, associated gene expression in gastric epithelial cells, and its implication in pathogenesis.

    PubMed

    Ding, Song-Ze; Fischer, Wolfgang; Kaparakis-Liaskos, Maria; Liechti, George; Merrell, D Scott; Grant, Patrick A; Ferrero, Richard L; Crowe, Sheila E; Haas, Rainer; Hatakeyama, Masanori; Goldberg, Joanna B

    2010-01-01

    Histone modifications are critical in regulating gene expression, cell cycle, cell proliferation, and development. Relatively few studies have investigated whether Helicobacter pylori, the major cause of human gastric diseases, affects histone modification. We therefore investigated the effects of H. pylori infection on histone modifications in a global and promoter-specific manner in gastric epithelial cells. Infection of gastric epithelial cells by wild-type H. pylori induced time- and dose-dependent dephosphorylation of histone H3 at serine 10 (H3 Ser10) and decreased acetylation of H3 lysine 23, but had no effects on seven other specific modifications. Different cag pathogenicity island (PAI)-containing-clinical isolates showed similar abilities to induce H3 Ser10 dephosphorylation. Mutation of cagA, vacA, nonphosphorylateable CagA mutant cagA(EPISA), or disruption of the flagella showed no effects, while deletion of the entire cagPAI restored the H3 Ser10 phosphorylation to control levels. Analysis of 27 cagPAI mutants indicated that the genes that caused H3 Ser10 dephosphorylation were similar to those that were previously found to induce interleukin-8, irrespective of CagA translocation. This effect was independent of ERK or p38 pathways and type I interferon signaling. Additionally, c-Jun and hsp70 gene expression was associated with this histone modification. These results demonstrate that H. pylori alters histone modification and host response via a cagA-, vacA-independent, but cagPAI-dependent mechanisms, which contribute to its persistent infection and pathogenesis. PMID:20368982

  14. Analysis of surface-exposed outer membrane proteins in Helicobacter pylori.

    PubMed

    Voss, Bradley J; Gaddy, Jennifer A; McDonald, W Hayes; Cover, Timothy L

    2014-07-01

    More than 50 Helicobacter pylori genes are predicted to encode outer membrane proteins (OMPs), but there has been relatively little experimental investigation of the H. pylori cell surface proteome. In this study, we used selective biotinylation to label proteins localized to the surface of H. pylori, along with differential detergent extraction procedures to isolate proteins localized to the outer membrane. Proteins that met multiple criteria for surface-exposed outer membrane localization included known adhesins, as well as Cag proteins required for activity of the cag type IV secretion system, putative lipoproteins, and other proteins not previously recognized as cell surface components. We identified sites of nontryptic cleavage consistent with signal sequence cleavage, as well as C-terminal motifs that may be important for protein localization. A subset of surface-exposed proteins were highly susceptible to proteolysis when intact bacteria were treated with proteinase K. Most Hop and Hom OMPs were susceptible to proteolysis, whereas Hor and Hof proteins were relatively resistant. Most of the protease-susceptible OMPs contain a large protease-susceptible extracellular domain exported beyond the outer membrane and a protease-resistant domain at the C terminus with a predicted ?-barrel structure. These features suggest that, similar to the secretion of the VacA passenger domain, the N-terminal domains of protease-susceptible OMPs are exported through an autotransporter pathway. Collectively, these results provide new insights into the repertoire of surface-exposed H. pylori proteins that may mediate bacterium-host interactions, as well as the cell surface topology of these proteins. PMID:24769695

  15. 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

  16. A novel line immunoassay based on recombinant virulence factors enables highly specific and sensitive serologic diagnosis of Helicobacter pylori infection.

    PubMed

    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; Gerhard, Markus

    2013-11-01

    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

  17. 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

  18. An Update on Helicobacter pylori as the Cause of Gastric Cancer

    PubMed Central

    Zhang, Wei; Lu, Hong; Graham, David Y.

    2014-01-01

    Background Gastric cancer is the second most common cause of cancer deaths worldwide. The vast majority of gastric cancers are inflammation-related cancers caused by infection with Helicobacter pylori. H. pylori-induced oxidative stress damages DNA, resulting in genetic instability. In addition, H. pylori itself can cause DNA damage and epigenetic changes that trigger genetic instability and neoplastic transformation. Summary H. pylori strain-specific components act in combination with host factors and environmental and dietary factors to greatly enhance the inflammatory response and thus the cancer risk. Variations in several key factors, such as the cag pathogenicity island and the VacA protein, can trigger a greater inflammatory response in host cells. Genetic polymorphisms in the host such as in the IL-1? gene, and chromosomes 9p21.3 and 10q23 also play a contributing role. Finally, diet is a major external factor that modulates the risk of gastric cancer. Key Message The majority of gastric cancers are inflammation-related cancers caused by infection with H. pylori. Eradication of H. pylori is important for the prevention and treatment of gastric cancer. Practical Implications H. pylori eradication results in healing of gastritis and prevention of further H. pylori-induced genetic damage. Eradication of H. pylori prior to development of atrophic gastritis can prevent the development of gastric cancer. Japan has undertaken a nationwide program to identify and eliminate H. pylori, along with surveillance for those who underwent H. pylori eradication too late to eliminate cancer risk. Population-wide eradication of H. pylori will result in gastric cancer becoming a vanishingly rare disease. PMID:26672968

  19. Soluble Extracts from Helicobacter pylori Induce Dome Formation in Polarized Intestinal Epithelial Monolayers in a Laminin-Dependent Manner

    PubMed Central

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

    2003-01-01

    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 α6β4 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

  20. Genetic Analysis of Helicobacter pylori Strain Populations Colonizing the Stomach at Different Times Postinfection? †

    PubMed Central

    Salama, Nina R.; Gonzalez-Valencia, Gerardo; Deatherage, Brooke; Aviles-Jimenez, Francisco; Atherton, John C.; Graham, David Y.; Torres, Javier

    2007-01-01

    Genetic diversity of the human gastric pathogen Helicobacter pylori in an individual host has been observed; whether this diversity represents diversification of a founding strain or a mixed infection with distinct strain populations is not clear. To examine this issue, we analyzed multiple single-colony isolates from two to four separate stomach biopsies of eight adult and four pediatric patients from a high-incidence Mexican population. Eleven of the 12 patients contained isolates with identical random amplified polymorphic DNA, amplified fragment length polymorphism, and vacA allele molecular footprints, whereas a single adult patient had two distinct profiles. Comparative genomic hybridization using whole-genome microarrays (array CGH) revealed variation in 24 to 67 genes in isolates from patients with similar molecular footprints. The one patient with distinct profiles contained two strain populations differing at 113 gene loci, including the cag pathogenicity island virulence genes. The two strain populations in this single host had different spatial distributions in the stomach and exhibited very limited genetic exchange. The total genetic divergence and pairwise genetic divergence between isolates from adults and isolates from children were not statistically different. We also analyzed isolates obtained 15 and 90 days after experimental infection of humans and found no evidence of genetic divergence, indicating that transmission to a new host does not induce rapid genetic changes in the bacterial population in the human stomach. Our data suggest that humans are infected with a population of closely related strains that vary at a small number of gene loci, that this population of strains may already be present when an infection is acquired, and that even during superinfection genetic exchange among distinct strains is rare. PMID:17337568

  1. Virulence genes of Helicobacter pylori in the Dominican Republic.

    PubMed

    Shiota, Seiji; Cruz, Modesto; Abreu, José A Jiménez; Mitsui, Takahiro; Terao, Hideo; Disla, Mildre; Iwatani, Shun; Nagashima, Hiroyuki; Matsuda, Miyuki; Uchida, Tomohisa; Tronilo, Lourdes; Rodríguez, Eduardo; Yamaoka, Yoshio

    2014-09-01

    Although the incidence of gastric cancer in the Dominican Republic is not high, the disease remains a significant health problem. We first conducted a detailed analysis of Helicobacter pylori status in the Dominican Republic. In total, 158 patients (103 females and 55 males; mean age 47.1±16.2 years) were recruited. The status of H. pylori infection was determined based on four tests: rapid urease test, culture test, histological test and immunohistochemistry. The status of cagA and vacA genotypes in H. pylori was examined using PCR and gene sequencing. The overall prevalence of H. pylori infection was 58.9?%. No relationship was found between the H. pylori infection rate and the age range of 17-91 years. Even in the youngest group (patients aged <29 years), the H. pylori infection rate was 62.5?%. Peptic ulcer was found in 23 patients and gastric cancer was found in one patient. The H. pylori infection rate in patients with peptic ulcer was significantly higher than that in patients with gastritis (82.6 versus 54.5?%, P<0.01). The cagA-positive/vacA s1m1 genotype was the most prevalent (43/64, 67.2?%). Compared with H. pylori-negative patients, H. pylori-positive patients showed more severe gastritis. Furthermore, the presence of cagA was related to the presence of more severe gastritis. All CagA-positive strains had Western-type CagA. In conclusion, we found that H. pylori infection is a risk factor for peptic ulcer in the Dominican Republic. Patients with cagA-positive H. pylori could be at higher risk for severe inflammation and atrophy. PMID:24965801

  2. 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

  3. Helicobacter pylori-Induced Histone Modification, Associated Gene Expression in Gastric Epithelial Cells, and Its Implication in Pathogenesis

    PubMed Central

    Ding, Song-Ze; Fischer, Wolfgang; Kaparakis-Liaskos, Maria; Liechti, George; Merrell, D. Scott; Grant, Patrick A.; Ferrero, Richard L.; Crowe, Sheila E.; Haas, Rainer; Hatakeyama, Masanori; Goldberg, Joanna B.

    2010-01-01

    Histone modifications are critical in regulating gene expression, cell cycle, cell proliferation, and development. Relatively few studies have investigated whether Helicobacter pylori, the major cause of human gastric diseases, affects histone modification. We therefore investigated the effects of H. pylori infection on histone modifications in a global and promoter-specific manner in gastric epithelial cells. Infection of gastric epithelial cells by wild-type H. pylori induced time- and dose-dependent dephosphorylation of histone H3 at serine 10 (H3 Ser10) and decreased acetylation of H3 lysine 23, but had no effects on seven other specific modifications. Different cag pathogenicity island (PAI)-containing-clinical isolates showed similar abilities to induce H3 Ser10 dephosphorylation. Mutation of cagA, vacA, nonphosphorylateable CagA mutant cagAEPISA, or disruption of the flagella showed no effects, while deletion of the entire cagPAI restored the H3 Ser10 phosphorylation to control levels. Analysis of 27 cagPAI mutants indicated that the genes that caused H3 Ser10 dephosphorylation were similar to those that were previously found to induce interleukin-8, irrespective of CagA translocation. This effect was independent of ERK or p38 pathways and type I interferon signaling. Additionally, c-Jun and hsp70 gene expression was associated with this histone modification. These results demonstrate that H. pylori alters histone modification and host response via a cagA-, vacA-independent, but cagPAI-dependent mechanisms, which contribute to its persistent infection and pathogenesis. PMID:20368982

  4. 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.

  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. 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, ?-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

  7. A Novel Pathogenicity Island Integrated Adjacent to the thrW tRNA Gene of Avian Pathogenic Escherichia coli Encodes a Vacuolating Autotransporter Toxin

    PubMed Central

    Parreira, V. R.; Gyles, C. L.

    2003-01-01

    We report the complete nucleotide sequence and genetic organization of the Vat-encoding pathogenicity island (PAI) of avian pathogenic Escherichia coli strain Ec222. The 22,139-bp PAI is situated adjacent to the 3? terminus of the thrW tRNA gene, has a G+C content of 41.2%, and includes a bacteriophage SfII integrase gene, mobile genetic elements, two open reading frames with products exhibiting sequence similarity to known proteins, and several other open reading frames of unknown function. The PAI encodes an autotransporter protein, Vat (vacuolating autotransporter toxin), which induces the formation of intracellular vacuoles resulting in cytotoxic effects similar to those caused by the VacA toxin from Helicobacter pylori. The predicted 148.3-kDa protein product possesses the three domains that are typical of serine protease autotransporters of Enterobacteriaceae: an N-terminal signal sequence of 55 amino acids, a 111.8-kDa passenger domain containing a modified serine protease site (ATSGSG), and a C-terminal outer membrane translocator of 30.5 kDa. Vat has 75% protein homology with the hemagglutinin Tsh, an autotransporter of avian pathogenic E. coli. A vat deletion mutant of Ec222 showed no virulence in respiratory and cellulitis infection models of disease in broiler chickens. We conclude that the newly described PAI and Vat may be involved in the pathogenicity of avian septicemic E. coli strain Ec222 and other avian pathogenic E. coli strains. PMID:12933851

  8. 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, ?-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

  9. 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:21039971

  10. The microbiological, histological, immunological and molecular determinants of Helicobacter pylori infection in guinea pigs as a convenient animal model to study pathogenicity of these bacteria and the infection dependent immune response of the host.

    PubMed

    Walencka, Maria; Gonciarz, Weronika; Mnich, Eliza; Gajewski, Adrian; Stawerski, Pawel; Knapik-Dabrowicz, Alina; Chmiela, Magdalena

    2015-01-01

    Helicobacter pylori is an etiological agent of chronic gastritis, gastric and duodenal ulcers and gastric cancers. The use of an appropriate animal model for experimental studies on the pathogenesis of H. pylori infections is necessary due to the chronic character of such infections and difficulties in identifying their early stage in humans. The aim of this study was to develop a guinea pig model of H. pylori infection and identify its microbiological, histological, serological and molecular determinants. Guinea pigs were inoculated per os with H. pylori strains: CCUG 17874 or ATCC 700312, both producing vacuolating cytotoxin A (VacA) and cytotoxin associated gene A (CagA) protein, suspended in Brucella broth with fetal calf serum (FCS) and Skirrow supplement of antibiotics. To determine H. pylori colonization, 7 and 28 days after the challenge, a panel of diagnostic methods was used. It included culturing of microorganisms from the gastric tissue, histopathological analysis of gastric sections, stained by Mayer,s haematoxylin and eosin to assess inflammatory response, by Giemsa as well as Warthin-Starry silver staining to visualise Helicobacter-like organisms (HLO) and with anti-Ki-67 antigen to assess epithelial cell proliferation. H. pylori infection was also confirmed by polymerase chain reactions (PCR) for detection in gastric tissue of ureC and cagA genes and by serological assessment of H. pylori antigens in faeces. This study showed the usefulness of microbiological, histological, immunological and molecular methods for the detection of persistent H. pylori infections in guinea pigs, which could be an appropriate model for studying H. pylori pathogenesis and the related immune response against these microbes. PMID:26610308

  11. Implications of Molecular Genotyping of Helicobacter pylori Isolates from Different Human Populations by Genomic Fingerprinting of Enterobacterial Repetitive Intergenic Consensus Regions for Strain Identification and Geographic Evolution

    PubMed Central

    Hussain, M. Abid; Kauser, Farhana; Khan, Aleem A.; Tiwari, Santosh; Habibullah, Chittoor M.; Ahmed, Niyaz

    2004-01-01

    Biogeographic partitioning of the genome is typical of the gastric pathogen Helicobacter pylori. Such population-specific evolution could serve as a model for understanding host-pathogen interaction and the impact of genetic drift and recombination on insular populations. With a total of 320 isolates from six geographic regions (Japan, India, England, Spain, Ireland, Africa, and Peru) analyzed by enterobacterial repetitive intergenic consensus (ERIC)-based genotyping, we examined genetic affinities among various H. pylori populations in the world. Several strain-specific and region-specific differences were observed by ERIC-based typing. Polymorphic ERIC patterns indicated that the ERIC sequences are in fact dispersed in the H. pylori chromosome at different locations separated by various distances. Phylogenetic analysis of 61 representative isolates revealed three distinct genetic clusters populated by isolates with shared ERIC types independent of the cag right-junction motif type and vacA allele status. Among the notable genetic relationships were the genotypic similarities between Irish and Japanese and between Peruvian and Japanese isolates. Insular genotypic characteristics of Irish isolates amid genetic similarity to East Asian, as well as North European, strains have been once again proved in this study. Peruvian genotypes were more similar to those of Japanese isolates than to those of Iberian or European isolates. Given the current debate on the origin and age of present-day H. pylori, this is a significant finding that supports the possibility of ancient colonization of Amerindians with East Asian strains. Genotypic data presented here will be additionally helpful in realizing the importance of H. pylori geographical genomics in the development of gastroduodenal pathology. PMID:15184407

  12. Proteomic analysis of upregulated proteins in Helicobacter pylori under oxidative stress induced by hydrogen peroxide.

    PubMed

    Huang, Chun-Hao; Chiou, Shyh-Horng

    2011-12-01

    The development of gastric cancer was suggested to be associated with chronic inflammation as a consequence of Helicobacter pylori infection. Such inflammation-related oxidative stress induced by reactive oxygen species (ROS) in vivo may exert bidirectional effects on both hosts and H pylori. In this study, ROS-induced oxidative stress was mimicked by coculture of gastric epithelial cells with H pylori treated with hydrogen peroxide (H(2)O(2)). To investigate the effect of H(2)O(2) on the proteome of H pylori, we performed two-dimensional polyacrylamide gel electrophoresis followed by liquid chromatography coupled with nano-electrospray ionization-tandem mass spectrometry (liquid chromatography mass spectrometry) and bioinformatics database analysis. The nine most overexpressed proteins consisted of three virulence factors, including cytotoxin-associated protein A (CagA), vacuolating cytotoxin (VacA), adherence-associated protein (AlpA), and two antioxidant enzymes alkylhydroperoxide reductase (AhpC) and catalase (KatA), plus one serine protease (HtrA), aconitate hydratase, and fumarate reductase. We have also confirmed the upregulation of virulence factors and antioxidant proteins in several H pylori strains isolated from patients of different clinical outcomes. Furthermore, it is noted that H pylori was found to decrease in infection rate and increase in proliferation after being exposed to H(2)O(2). We also found that gastric epithelial cells can be protected from oxidative damage by H(2)O(2) in the presence of H pylori. In conclusion, this study lends support to the supposition that ROS containing H(2)O(2) as one of the major oxidative species can induce upregulation of virulence factors and antioxidant enzymes in H pylori, which may aid in the elucidation of inflammation leading to the development of gastric cancer from H pylori infection. PMID:22208537

  13. MTHFR C677T polymorphism and differential methylation status in gastric cancer: an association with Helicobacter pylori infection.

    PubMed

    Neves Filho, Eduardo Henrique Cunha; Alves, Markenia Kelia Santos; Lima, Valeska Portela; Rabenhorst, Silvia Helena Barem

    2010-12-01

    MTHFR C677T and Helicobacter pylori infection are believed to play critical roles in the DNA methylation process, an epigenetic feature frequently found in gastric cancer. The aim of this study was to verify the associations between the MTHFR C677T polymorphism and the methylation status of three gastric cancer-related genes. The influence of H. pylori strains was also assessed. DNA extracted from 71 gastric tumor samples was available for MTHFR C677T genotyping by PCR-RFLP, promoter methylation identification by MS-PCR and H. pylori detection and posterior subtyping (cagA and vacA genes) by PCR. In the distal tumors, a positive correlation was found between the methylation of CDKN2A and the allele T carriers (r=0.357; p=0.009). Considering the eldest patients (age ?60 years old), this correlation was even higher (r=0,417; p=0.014). H. pylori infection by highly pathogenic strains (cagA+/vacAs1m1) was also found correlated to promoter methylation of CDKN2A and the allele T carriers in distal tumors (r=0.484; p=0.026). No significant correlation was verified between MTHFR C677T genotype and promoter methylation status when we analyzed the general sample. DNA methylation in CDKN2A associated to the MTHFR 677T carrier is suggested to be a distal tumor characteristic, especially in those 60 years old or older, and it seems to depend on the infection by H. pylori cagA/vacAs1m1 strains. PMID:20957490

  14. Mucosal interleukin-21 mRNA expression level is high in patients with Helicobacter pylori and is associated with the severity of gastritis

    PubMed Central

    Bagheri, Nader; Azadegan-Dehkordi, Fatemeh; Zamanzad, Benham; Rahimian, Ghorbanali; Taghikhani, Afshin; Rafieian-Kopaei, Mahmoud; Shirzad, Hedayatollah

    2015-01-01

    Helicobacter pylori (H. pylori) infection is associated with gastritis and marked infiltration of the gastric mucosa by several cytokines secreting inflammatory cells. Different clinical forms of the infection may reflect distinctive patterns of cytokine expression. Interleukin (IL)-17, IL-21, IL-22, and IL-23 have been reported to be involved in H. pylori-induced gastric mucosal inflammation, but the details and relationship to different patterns of inflammation and virulence factors remain unclear. The present study was launched to analyse IL-6 expression in H. pylori-infected and uninfected gastric patients and to investigate its correlation with chronic gastritis among H. pylori-infected patients. Total RNA was extracted from the gastric antrum biopsies of 48 H. pylori-infected patients and 38 H. pylori uninfected patients. Mucosal IL-21 mRNA expression level in H. pylori-infected and uninfected gastric biopsy was determined by real-time PCR. The presence of vacA (vacuolating cytotoxin A) and cagA (cytotoxin associated gene A) virulence factors were evaluated using PCR. Interleukin-21 mRNA expression was significantly high in biopsies of H. pylori-infected patients compared to H. pylori uninfected patients, and the mucosal IL-21 mRNA level was positively correlated with the grade of chronic inflammation. There was no association between virulence factors and IL-21 mRNA expression. We believe that IL-21 might be involved in the pathogenesis of H. pylori and might be an index of the severity of chronic gastritis. PMID:26155185

  15. 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 H. pylori infection. PMID:25660579

  16. Recombinant human lactoferrin enhances the efficacy of triple therapy in mice infected with Helicobacter pylori.

    PubMed

    Yuan, Yuping; Wu, Qinyi; Cheng, Guoxiang; Liu, Xuefang; Liu, Siguo; Luo, Juan; Zhang, Aimin; Bian, Li; Chen, Jianquan; Lv, Jiajun; Dong, Xiangqian; Yang, Gang; Zhu, Yunzhen; Ma, Lanqing

    2015-08-01

    Helicobacter pylori (H. pylori) is a life-threatening pathogen which causes chronic gastritis, gastric ulcers and even stomach cancer. Treatment normally involves bacterial eradication; however, this type of treatment only has a rate of effectiveness of <80%. Thus, it is a matter of some urgency to develop new therapeutic strategies. Lactoferrin, a member of the transferrin family of iron-binding proteins, has been proven to be effective in removing a vast range of pathogens, including H. pylori. In the present study, we examined the effectiveness of recombinant human lactoferrin (rhLf) isolated from transgenic goats as a treatment for H. pylori in vitro and in vivo. For the in vivo experiments, BALB/c mice received an intragastric administration of 0.1 ml of a suspension of H. pylori. The mice were then divided into 4 groups: group A, treated with saline; group B, treated with 1.5 g of rhLF; group C, treated with the standard triple therapy regimen; and group D, treated with the standard triple therapy regimen plus.5 g of rhLF. Following sacrifice, the stomach tissues of the mice were histologically examined for the presence of bacteria. For the in vitro experiments, the bacteria were cultured in BHI broth and RT-qPCR and western blot analysis were carried out to determine the mRNA and protein levels of virulence factors (CagA and VacA) in the cultures. Our results revealed that rhLf not only inhibited the growth of H. pylori, but also suppressed the expression of two major virulence factors. Moreover, rhLf markedly increased bacterial eradication and effectively reduced the inflammatory response when combined with the standard triple therapy regimen. These results provide evidence supporting the use of rhLF as an adjuvant to traditional therapeutic strategies in the treatment of H. pylori. PMID:26080893

  17. Helicobacter pylori in Iran: A systematic review on the association of genotypes and gastroduodenal diseases

    PubMed Central

    Hosseini, Elham; Poursina, Farkhondeh; de Wiele, Tom Van; Safaei, Hajieh Ghasemian; Adibi, Peyman

    2012-01-01

    Background: Helicobacter pylori (H. pylori) infection is known as a major etiologic factor for a variety of gastroduodenal diseases. In Iran, with a high rate of H. pylori infection close to 90%, numerous studies have revealed many aspects of interaction between the bacterium, mucosal surface and induction of disease outcome. The organism is genetically diverse and several virulence factors are attributed to the more virulent strains. The well-characterized virulence factors of H. pylori are cytotoxin associated gene A and vacuolating cytotoxin gene A. The distribution pattern of H. pylori genotypes and its association with disease status varies geographically. The present review focused on the virulence factors and genotyping of H. pylori in relation to gastroduodenal disorders in different regions of Iran. Methods: In total, 398 studies were reported on different aspects related to H. pylori in our electronic search from 1995-2011. H. pylori infection and its virulence factors in association with disease status were investigated in 159 reports. Looking specifically at the gastrointestinal tract disorders, the most relevant reports including 37 papers were selected. Results: We found no correlation of cagA genotype and disease status in the majority of studies, whereas vacA was demonstrated as a useful marker in predicting the disease outcome. The results of reports on other virulence factors of H. pylori such as blood group antigen-binding adhesion gene A, the induced by contact with epithelium gene A, the outer inflammatory protein A, the duodenal ulcer promoting gene A, and Helicobacter outer membrane gene and their relation with disease status were contradictory. Conclusions: Although different markers of H. pylori were emphasized as useful when predicting disease outcomes in some studies, the inconsistent researches and the scarcity of data made any conclusion or even comparison impossible. Considering the gap of information observed during our search relating to genotyping and other aspects of H. pylori infection, further investigations are suggested. PMID:23267382

  18. 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

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

    PubMed Central

    Siavoshi, Farideh; Saniee, Parastoo

    2014-01-01

    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

  20. Multiplex H. pylori Serology and Risk of Gastric Cardia and Noncardia Adenocarcinomas.

    PubMed

    Shakeri, Ramin; Malekzadeh, Reza; Nasrollahzadeh, Dariush; Pawilta, Michael; Murphy, Gwen; Islami, Farhad; Sotoudeh, Masoud; Michel, Angelika; Etemadi, Arash; Waterboer, Tim; Poustchi, Hossein; Brennan, Paul; Boffetta, Paolo; Dawsey, Sanford M; Kamangar, Farin; Abnet, Christian C

    2015-11-15

    The reported associations with gastric adenocarcinoma and seropositivity to different Helicobacter pylori antigens using multiplex serology have not been consistent across studies. We aimed to investigate the association between 15 different multiplex serology antigens and the risk of gastric cardia (GCA) and gastric noncardia (GNCA) adenocarcinomas in northeastern Iran, a population with high rates of gastric adenocarcinoma. We included 272 cases of gastric adenocarcinoma (142 GCA, 103 GNCA, and 27 unspecified) and 524 controls who were individually matched to cases for age, sex, and place of residence in a population-based case-control study. Seropositivity to H. pylori was assessed using both multiplex serology and H. pylori IgG ELISA. Ninety-five percent of controls were seropositive to H. pylori. Of the 15 antibodies in the multiplex assay, 11 showed no significant association with gastric adenocarcinomas. CagA and VacA were associated with a significantly increased risk of all gastric adenocarcinoma and GNCA in multivariate models. Surprisingly, GroEL and NapA were significantly associated with a reduced risk of these tumors. Only CagA antigen was associated with significantly elevated risk of GCA. We found no associations between H. pylori seropositivity overall either by whole-cell ELISA test or multiplex serology, likely due to the high prevalence of seropositivity. Individual antigen testing showed that CagA positivity was associated with increased risk of both noncardia and cardia adenocarcinoma, which is similar to some other Asian populations, whereas two antigens were associated with lower risk of gastric cancer. This latter result was unexpected and should be retested in other populations. Cancer Res; 75(22); 4876-83. ©2015 AACR. PMID:26383162

  1. Clinical Relevance and Diversity of Two Homologous Genes Encoding Glycosyltransferases in Helicobacter pylori▿

    PubMed Central

    Oleastro, Mónica; Santos, Andrea; Cordeiro, Rita; Nunes, Baltazar; Mégraud, Francis; Ménard, Armelle

    2010-01-01

    Helicobacter pylori is known to be a major cause of peptic ulceration. The jhp0562 gene, encoding a glycosyltransferase involved in the synthesis of the lipopolysaccharide, was associated with peptic ulcer disease (PUD) in children. The β-(1,3)-galactosyltransferase [β-(1,3)GalT] gene (jhp0563), involved in Lewis (Le) antigen expression, is highly similar to jhp0562. The clinical significance and diversity of both genes were examined by PCR and sequencing of clinical strains (n = 117) isolated from children with PUD (n = 57) and nonulcer dyspepsia (NUD; n = 60). The prevalence of the jhp0562 gene was significantly higher in strains with a more-virulent profile (strains positive for the cag pathogenicity island [PAI], vacA sl allele, babA, homB, phase-variable gene oipA “on” [i.e., functional], and hopQ I allele). The distribution of genotypes according to clinical outcome showed that the presence of jhp0562 represented one of the greatest risks for the development of PUD. Moreover, the triple-positive genotype for the cag PAI, jhp0562, and homB provided the best discriminatory model for distinguishing PUD and NUD outcomes in children. Sequence and in vitro expression analyses of jhp0562 showed the presence of a complete open reading frame, while the β-(1,3)GalT gene was shown to be a phase-variable gene. The regular presence of jhp0562 in strains with a truncated β-(1,3)GalT gene suggests that jhp0562 may also be implicated in the regulation of Le antigen expression. Overall, the results of this study suggest that the jhp0562 gene is of great clinical relevance, being a useful comarker for severe H. pylori-related disease and contributing to host adaptation. PMID:20554820

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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.

  8. [What are the gastric modifications induced by acute and chronic Helicobacter pylori infection?].

    PubMed

    Lamarque, Dominique; Tran Van Nhieu, Jeanne; Breban, Maxime

    2003-03-01

    H. pylori colonisation of the stomach causes the recruitment of the inflammatory cells by the adherence of the bacteria with the epithelium and the release of factors of virulence either to the contact (oipA or other soluble factors) or in the cell by translocation (CagA). Such contact triggers interleukin 8 expression in the epithelial cell and attracts lymphocytes and monocytes into the chorion. Bacterial lipopolysaccharide and urease support the activation of these inflammatory cells. The lymphocytes produce pro-inflammatory cytokines, which direct the immune response towards the Th1 pathway. The variability of the inflammatory response depends on hereditary factors of the host such as the interleukin 1 genotypes, which determine the level of the pro-inflammatory cytokine expression, and of bacterial factors such as the cag pathogenicity island, the lipopolysaccharide and the vacuolating toxin, vacA. The mucosal inflammation provokes apoptosis and atrophy of the epithelial cells through the effect of pro-inflammatory cytokines and free radicals. Epithelial proliferation is a consequence of excessive apoptosis caused by the infection. It is stimulated by the expression of inducible cyclo-oxygenase and inducible nitric oxide synthase. The development of atrophic gastritis towards cancer is supported by nitric oxide which has a mutagenic effect on DNA and inhibits p53 protein and by the bacterium itself which decreases DNA mismatch repairing activity. The gastritis induced by Helicobacter pylori changes acid secretion according to the prevalent location of the gastritis in the antrum or in the gastric body. Prevalent gastritis in the gastric body causes hypochlorhydria by reducing the release of histamin from ECL cells and inhibiting the parietal cells through the effect of tumor necrosis factor and interleukin 1-beta. Hypochlorhydria is more marked among patients having a pro-inflammatory genotype for interleukin 1-beta and those infected by bacteria with virulence factors. In the event of antrum predominant gastritis, the pro-inflammatory cytokines cause a reduction of somatostatin and gastrin releases from the D and the G cells, respectively. The result of all is increased maximal acid output and the meal-stimulated acid secretion. PMID:12700495

  9. 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 duplicated segments are clearly associated with shortening. Therefore, our field observations show that the host rock is pushed and shortened ahead of the sill tips, in total contradiction with the extensional features predicted by the LEFM theory. The structures described above strongly suggest instead that these sills were emplaced according to the viscous indenter model, in good agreement with recent laboratory models (Abdelmalak et al., 2012). These detailed observations strongly question the geological relevance of the LEFM theory applied to igneous sheet intrusions, and call for more field observations to better constrain the dynamics of sill and dyke emplacement mechanisms. Abdelmalak, M.M., Mourgues, R., Galland, O., Bureau, D., 2012. Fracture mode analysis and related surface deformation during dyke intrusion: Results from 2D experimental modelling. Earth Planet. Sci. Lett. 359-360, 93-105.

  10. 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-mediated protection against allergy in humans. PMID:27014260

  11. Molecular alterations in fibroblasts exposed to Helicobacter pylori: a missing link in bacterial inflammation progressing into gastric carcinogenesis?

    PubMed

    Krzysiek-Maczka, G; Targosz, A; Ptak-Belowska, A; Korbut, E; Szczyrk, U; Strzalka, M; Brzozowski, T

    2013-02-01

    Major human pathogen Helicobacter pylori (Hp) can colonize the gastric mucosa causing inflammation and being of potential risk for gastric cancer development but the contribution of fibroblasts to the pathogenesis of Hp in the stomach has been little studied. Normal stroma contains few fibroblasts, especially myofibroblasts, but their number rapidly increases in the reactive stroma surrounding inflammatory region and neoplastic tissue. We determined the effect of coincubation of cultured rat gastric fibroblasts with alive Hp on the transdifferentiation of fibroblasts into myofibroblasts associated with Hp-induced inflammation and neoplasia. Gastric mucosal samples were harvested from 8-week-old Spraque-Dowley rats and cultured to obtain the sub-confluent fibroblasts. The isolated fibroblasts were infected with 1 x 10(9) of live Hp (ATCC 700824, cagA+, vacA+) per dish and incubated in humidified atmosphere for 3, 24 and 48 hours. At respective times, fibroblasts were harvested and the expression of mRNA for α-smooth muscle actin (SMA), hypoxia inducible factor (HIF)-1α, collagen I, heat shock protein (HSP)-70, heme oxygenase (HO)-1, Bax and Ki67 transcripts was determined by RT-PCR with specific primers. Hp increased the transdifferentiation of fibroblasts into myofibroblasts as reflected by the time-dependent overexpression of mRNA for α-SMA. The increased expression of HIF-1α and collagen I was observed in fibroblasts co-cultured with Hp. The expression of HSP70 which was negligible in isolated fibroblasts incubated with vehicle (saline) showed time-dependent 2-3 fold increase in those incubated with Hp. The HO-1 mRNA was strongly expressed in rat gastric fibroblasts without or with the co-incubation with Hp. The mRNA for Bax was progressively downregulated within the time of incubation while no significant changes in expression of proliferation marker Ki67 were recorded. We conclude that Hp-induced transdifferentiation of fibroblasts into myofibroblasts involves an increased expression of the early carcinogenic marker HIF-1α, and inhibition of proapoptotic Bax expression, and 2) the overexpression of HSP70 and the unchanged expression HO-1 and Ki67 probably represent the enhanced protective activity of Hp-infected fibroblasts to maintain their own integrity under inflammatory action of this bacteria and its cytotoxins. PMID:23568974

  12. 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.

  13. 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-specific effects, and add strength to the suggestion of an oceanography-driven, major spatial transition in coastal communities at 30–31°S. PMID:25334020

  14. The belt of metagabbros of La Pampa: Lower Paleozoic back-arc magmatism in south-central Argentina

    NASA Astrophysics Data System (ADS)

    Chernicoff, Carlos J.; Zappettini, Eduardo O.; Villar, Luisa M.; Chemale, Farid, Jr.; Hernández, Laura

    2009-12-01

    Combined geological, geochronological, geochemical and geophysical studies have led to identification of a large (˜300 km long, ˜5 km wide) N-S trending belt of metagabbros in the province of La Pampa, south-central Argentina. This belt, though only poorly exposed in the localities of Valle Daza and Sierra de Lonco Vaca, stands out in the geophysical data (aeromagnetics and gravity). Modeling of the aeromagnetic data permits estimation of the geometry of the belt of metagabbros and surrounding rocks. The main rock type exposed is metagabbros with relict magmatic nucleii where layering is preserved. A counterclockwise P-T evolution affected these rocks, i.e., during the Middle Ordovician the protolith reached an initial granulite facies of metamorphism (M1), evolving to amphibolite facies (M2). During the Upper Devonian, a retrograde, greenschist facies metamorphism (M3) partially affected the metagabbros. The whole-rock Sm-Nd data suggest a juvenile source from a depleted mantle, with model ages ranging from 552 to 574 Ma, and positive Epsilon values of 6.51-6.82. A crystallization age of 480 Ma is based on geological considerations, i.e. geochronological data of the host rocks as well as comparisons with the Las Aguilas mafic-ultramafic belt of Sierra de San Luis (central Argentina). The geochemical studies indicate an enriched MORB and back-arc signature. The La Pampa metagabbros are interpreted to be originated as a result of the extension that took place in a back-arc setting coevally with the Famatinian magmatic arc (very poorly exposed in the western part of the study area). The extensional event was 'aborted' by the collision of the Cuyania terrane with Pampia-Gondwana in the Middle Ordovician, causing deformation and metamorphism throughout the arc-back-arc region. The similarities between the La Pampa metagabbros and the mafic-ultramafic Las Aguilas belt of the Sierra de San Luis are very conspicuous, for example, the age (Lower Paleozoic), geochemical signature and timing of metamorphism (dated at ca. 465 Ma in the study area), which allow definition of a single, mafic back-arc belt in central Argentina, from San Luis to La Pampa.

  15. 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

  16. Concurrent genotyping of Helicobacter pylori virulence genes and human cytokine SNP sites using whole genome amplified DNA derived from minute amounts of gastric biopsy specimen DNA

    PubMed Central

    Ryberg, Anna; Borch, Kurt; Sun, Yi-Qian; Monstein, Hans-Jürg

    2008-01-01

    Background Bacterial and cellular genotyping is becoming increasingly important in the diagnosis of infectious diseases. However, difficulties in obtaining sufficient amount of bacterial and cellular DNA extracted from the same human biopsy specimens is often a limiting factor. In this study, total DNA (host and bacterial DNA) was isolated from minute amounts of gastric biopsy specimens and amplified by means of whole genome amplification using the multiple displacement amplification (MDA) technique. Subsequently, MDA-DNA was used for concurrent Helicobacter pylori and human host cellular DNA genotyping analysis using PCR-based methods. Results Total DNA was isolated from gastric biopsy specimens of 12 subjects with gastritis and 16 control subjects having a normal mucosa. The DNA was amplified using a multiple displacement amplification (MDA) kit. Next, concurrent genotyping was performed using H. pylori-specific virulence gene PCR amplification assays, pyrosequencing of bacterial 16S rDNA and PCR characterisation of various host genes. This includes Interleukin 1-beta (IL1B) and Interferon-gamma receptor (IFNGR1) SNP analysis, and Interleukin-1 receptor antagonist (IL1RN) variable tandem repeats (VNTR) in intron 2. Finally, regions of the vacA-gene were PCR amplified using M13-sequence tagged primers which allowed for direct DNA sequencing, omitting cloning of PCR amplicons. H. pylori specific multiplex PCR assays revealed the presence of H. pylori cagA and vacA genotypic variations in 11 of 12 gastritis biopsy specimens. Using pyrosequencing, 16S rDNA variable V3 region signatures of H. pylori were found in 11 of 12 individuals with gastritis, but in none of the control subjects. Similarly, IL1B and IFNGR1-SNP and IL1RN-VNTR patterns could be established in all individuals. Furthermore, sequencing of M13-sequence tagged vacA-PCR amplicons revealed the presence of highly diverse H. pylori vacA-s/i/m regions. Conclusion The PCR-based molecular typing methods applied, using MDA-amplified DNA derived from small amounts of gastric biopsy specimens, enabled a rapid and concurrent molecular analysis of bacterial and host genes in the same biopsy specimen. The principles and technologies used in this study could also be applied to any situation in which human host and microbial genes of interest in microbial-host interactions would need to be sequenced. PMID:18842150

  17. 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 waters are transported to the north by the Peru-Chile Current. Although the nutrients are kept in the system by coastal upwelling processes on their way north, total productivity is decreasing as the nutrients are gradually consumed on their way north and taken out of the system by sedimentation.

  18. 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-specific effects, and add strength to the suggestion of an oceanography-driven, major spatial transition in coastal communities at 30-31°S. PMID:25334020

  19. 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 ?m, 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.

  20. 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.

  1. 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

  2. Delineation of the High Enthalpy Reservoirs of the Sierra Nevada Volcanic Geothermal System, South-Central Chile

    NASA Astrophysics Data System (ADS)

    Alam, M.; Muñoz, M.; Parada, M.

    2011-12-01

    Geothermal system associated with the Pleistocene-Holocene Sierra Nevada volcano (SNVGS) in the Araucanía Region of Chile has surface manifestations from the north-western flank of the volcano, up to Manzanar and Malalcahuello. Baños del Toro, located on the northwestern flank of the volcano, has numerous fumaroles and acid pools (acid sulfate waters, T=~90°C, pH=2.1, TDS=3080 mg/L); while Aguas de la Vaca, near the base of the volcano, has a bubbling spring (chloride-sulfate waters, T=~60°C, pH=7.0, TDS=950 mg/L). Five shallow (<120m) wells (2 at Manzanar and 3 at Malalcahuello) dug and drilled in the Cautín River Valley discharge alkaline (pH= 9-10) waters with relatively low TDS (130-210mg/L). The main heat source of the geothermal system is apparently the magmatic system of the Sierra Nevada volcano. Liquiñe-Ofqui Fault Zone (LOFZ) that transects the area forms excellent conduits for the flow of the geothermal waters. The geothermal reservoirs are hosted in the volcanic rocks interceded with glacial deposits over the North Patagonian Batholith that forms an impermeable barrier, and thus constitutes the lower boundary of the geothermal system and also controls the lateral flow of the fluids. An equilibrium temperature of ~210°C is derived from gas geothermometry (CO2/Ar-H2/Ar) of the discharges at Baños del Toro. Geothermal fluids from the upflow area on the northwestern flank of the volcano migrate northwards to the Cautín River Valley. The geothermal system has a high enthalpy reservoir(s) on the northwestern flank of the Sierra Nevada volcano and low-enthalpy reservoirs in the Cautín River Valley that have been tapped to form spas at Manzanar and Malalcahuello. While sub-vertical fractures of LOFZ facilitate the recharge of the system, lateral flow of the geothermal fluids is apparently controlled by lithology; Melipueclo Pluton in particular prevents the westward flow from the upflow zone, causing the flow only northwards to Malalcahuello and subsequently westward on meeting poorly permeable Guapitrío Member of the Cura-Mallín Formation. This change in the flow direction from northwestward up to Malalcahuello to westward towards Manzanar is supported by topographic and hydrographic conditions as well, besides available geological and geophysical data. SNVGS is perhaps the most promising geothermal system in the area, considering the presence of high enthalpy reservoir and stable heat source, ideal for its development as geothermal resource. Acknowledgments: Authors would like to acknowledge the funding for this work through the PBCT PDA-07 project of CONICYT and Geothermal Program (Cátedra de Geotermia) of the Ministry of Energy and Mining, Government of Chile.

  3. Zircons in Eucrites: Pristine and Disturbed U-Pb Systematics

    NASA Astrophysics Data System (ADS)

    Bukovanska, M.; Ireland, T. R.

    1993-07-01

    In our previous studies of HED zircons we have found that the zircon U-Pb systems have been undisturbed and consistent with a formation age of 4.56 Ga. Zi from the eucrites Padvarninkai [1], Stannern [2], and Yamato 791438 [3] all show concordant compositions and even the eucritic enclaves in the Vaca Muerta mesosiderite appear to be undisturbed [4]. We have analyzed zircons found in pol sections from another six eucrites, Bereba, Cachari, Jonzac, Juvinas, Millbillil and Pasamonte. In addition, a relatively large (~10 micrometers) baddeleyite was discovered in Pasamonte and gives us a chance to examine the systematics of this phase in comparison to zircon. The zircons in these meteorites are typically less than 10 micrometer and occur in close association with ilmenite and chromite. Zircons and baddeleyite were analyzed for U-Th-Pb isotopes and trace-element abundances with the SHRIMP ion microprobe. The analytical techniques for ion microprobe analysis are described [4]. Owing to the small size of the zircons, most of them were entirely consumed during the U-Pb analyses and REE patterns were not measured. In addition, the sm size of the grains meant that there was significant beam overlap onto the surrou chromite and ilmenite with the possibility that the U-Pb normalization could be affected. The zircons are fairly typical of meteoritic zircons with U concentrat around 50-100 ppm with a high value of 300 ppm in a Pasamonte zircon. REE are al the range previously observed for meteoritic zircon. The baddeleyite has ~60 ppm and, in contrast to the extreme heavy REE enriched zircon patterns, has a slight light REE ennched pattern (La 1800 x CI; Lu 800 x CI) with a large Eu depletion. All U-Pb analyses are either concordant or reverse discordant (i.e. they have excess radiogenic Pb). Three of the sections (Jonzac, Juvinas, Millbillillie) ha large surface Pb contributions, but their compositions were consistent with concordant 4.56 Ga U-Pb. Pasamonte zircon was also concordant at 4.56 Ga and Ber was concordant to slightly reverse discordant at 4.534 +- 0.016 Ga. Cachari, how is distinct in that it shows a mixing line between concordant 4.56 Ga and a radiogenic common Pb with a ^207Pb/^206Pb of ~0.4. The lowest apparent ^207Pb/^2 age is 4.20 Ga. Cachan also has a number of petrographic features associated wit deformation; in particular one of the zircons has been sheared with an offset th the center of the grain. It is possible that the U-Pb systematics are reflecting event, which has caused isotopic disturbance in the mesosiderites. The Pasamonte baddeleyite may also be slightly disturbed with a young ^207Pb/^206Pb age of ~4. Ga; as yet we have no standard to calibrate U-Pb ratios. References: [1] Bukovanska M. et al. (1991) Meteoritics, 26, 325. [2] Ireland T. R. and Bukovanska M. (1992) Meteoritics 27, 237. [3] Ireland T. R. et al. (1992) XXIII, 569-570. [4] Ireland T. R. and Wlotzka F. (1992) EPSL, 109, 1-10.

  4. 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)-1?, IL-2, IL-4, IL-10, IL-12, tumor necrosis factor-? (TNF-?) and interferon (IFN)-?, 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 significantly increased the expression of IGF-1 (P < 0.05). Insulin levels from the pancreas and the apoptotic rate of islet ?-cells remained unchanged. Also, we observed no significant differences among cytokines levels, including IL-1?, IL-2, IL-4, IL-10, IL-12, TNF-? and IFN-?. IL-4 was the only exception, which increased at 6 (44.36 ± 25.17 vs 17.38 ± 3.47, P < 0.05) and 12 mo (33.41 ± 10.00 vs 18.91 ± 5.31, P < 0.05) after H. pylori infection. CONCLUSION: Long-term H. pylori infection is significantly associated with high levels of HbA1c in Mongolian gerbils, indicating a potential role of H. pylori infection in glucose dysregulation. PMID:26640335

  5. Geology, water resources and usable ground-water storage capacity of part of Solano County, California

    USGS Publications Warehouse

    Thomasson, H.G., Jr.; Olmsted, F.H.; LeRoux, E.F.

    1960-01-01

    The area described is confined largely to the valley-floor and foothill lands of Solano County, which lies directly between Sacramento, the State capital, and San Francisco. The area is considered in two subareas: The Putah area, which extends from Putah Creek southward to the Montezuma Hills and from the foothills of the Coast Ranges eastward to the west edge of the Yolo Bypass; and the Suisun-Fairfield area, which is to the southwest in the notch in the Coast Ranges through which the waters of the Great Central Valley of California reach San Francisco Bay. There are no known hydrologic interconnections between the two subareas, through either surface streams or underground aquifers. The climate of the area is characterized by warm, rainless summers and by cool winters in which temperatures seldom drop much below freezing. The rainfall ranges from about 17 inches per year along the east side to perhaps 24 inches in the foothills to the west, and irrigation is necessary for all crops except dry-farmed grains, pastures, and some orchards. PUTAH AREA The Putah area occupies the southwestern corner of the Sacramento Valley, a topographic and structural basin underlain by a thick accumulation of sediments eroded from the surrounding hills and mountains by the Sacramento River and its tributaries. The eastern Coast Ranges and foothills lying west of the Sacramento Valley are a generally northward-trending belt of eastward-dipping sedimentary rocks that range in age from Cretaceous to Pleistocene. Successively younger strata are exposed eastward, and the essentially undeformed deposits of late Pleistocene and Recent age that immediately underlie the valley lap onto the tilted sediments of the foothills. Most of the streams of the Putah area rise east of the high ridge of Cretaceous rocks marking the western boundaries of Solano and Yolo Counties, but Putah Creek, the largest stream in the area, rises far west of that ridge and flows across it in a deep, narrow canyon. Putah Creek and the smaller streams have constructed an alluvial plain, herein designated the Putah plain, which slopes eastward and southeastward from the foothills toward the Sacramento River. A large part of the Putah plain is traversed by a branching set of distributary channel ridges or natural levees formed at times of overflow of Putah Creek. The rocks in the Putah area range in age from Cretaceous to Recent. For the purposes of this investigation they are divided into eight geologic or stratigraphic units, from youngest to oldest: (1) Stream-channel deposits, (2) younger alluvium, (3) older alluvium, (4) Tehama formation and related continental sediments, (5) volcanic sedimentary rocks, (6) basalt, (7) undifferentiated sedimentary rocks of Paleocene(?) and Eocene age, and (8) undifferentiated rocks of Cretaceous age. The stream-channel deposits are predominantly loose sand and gravel along the channel of Putah Creek. In part they are actively moving downstream and shifting. The younger alluvium, of Recent age, consists of flood-plain deposits underlying the Putah plain, Vaca Valley, Pleasants Valley, and the small valleys in the foothills north of Putah Creek and in the English Hills. Exposures of younger alluvium are characterized by soils lacking significant profile development and in many places by channel-ridge topography. The older alluvium occupies the stratigraphic interval between the younger alluvium and the Tehama formation and related continental sediments and is probably of late Pleistocene age. Its contact with the underlying Tehama formation and related continental sediments is unconformable near the foothills, but it may be gradational beneath much of the Putah plain. The base of the older alluvium is not well defined at many places but is inferred to be at the bottom of an irregular and ill-defined zone of coarse deposits, which ranges from about 50 feet to more than 150 feet below the land surface. Exposures of the older

  6. 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 identical oxygen isotope compositions; (ii) the presence in both of coarse-grained Mg-rich olivines; (iii) both have synchronous Lu-Hf and Mn-Cr ages; (iv) there are compositional similarities between the metal in both; and (v) mesosiderite-like material has been identified in a howardite breccia. The source of the mesosiderites remains an outstanding question in meteorite science. The underrepresentation of olivine-rich materials amongst both asteroids and meteorites results from a range of factors. However, evidence from pallasites and mesosiderites indicates that the most important reason for this olivine shortage lies in the early, catastrophic destruction of planetesimals in the terrestrial planet-forming region and the subsequent preferential loss of their olivine-rich mantles.

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

    NASA Astrophysics Data System (ADS)

    Zimmermann, Eric; Riccardi, Gerardo

    2000-08-01

    An improved mathematical hydrodynamic quasi-two-dimensional model of cells, CELSUB3, is presented for simulating drainage systems that consist of pumping well fields or subsurface drains. The CELSUB3 model is composed of an assemblage of algorithms that have been developed and tested previously and that simulate saturated flow in porous media, closed conduit flow, and flow through pumping stations. A new type of link between aquifer cells and drainage conduits is proposed. This link is verified in simple problems with well known analytical solutions. The correlation between results from analytical and mathematical solutions was considered satisfactory in all cases. To simulate more complex situations, the new proposed version, CELSUB3, was applied in a project designed to control the water-table level within a sewer system in Chañar Ladeado Town, Santa Fe Province, Argentina. Alternative drainage designs, which were evaluated under conditions of dynamic recharge caused by rainfall in a critical year (wettest year for the period of record) and a typical year, are briefly described. After analyzing ten alternative designs, the best technical-economic solution is a subsurface drainage system of closed conduits with pumping stations and evacuation channels. Résumé. Un modèle hydrodynamique perfectionné de cellules en quasi 2D, CELSUB3, est présenté dans le but de simuler des systèmes de drainage qui consistent en des champs de puits de pompage ou de drains souterrains. Le modèle CELSUB3 est composé d'un assemblage d'algorithmes développés et testés précédemment et qui simulent des écoulements en milieu poreux saturé, en conduites et dans des stations de pompage. Un nouveau type de lien entre des cellules d'aquifères et des drains est proposé. Ce lien est vérifié dans des problèmes simples dont les solutions analytiques sont bien connues. La corrélation entre les résultats des solutions analytiques et des solutions mathématiques a été considérée 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 alternativos, la mejor solución técnico-económica consistente en un sistema de drenes subterráneos, estaciones de bombeo y canales de evacuación.

  8. 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

    En el escenario estándar de la formación planetaria, los planetesimales (cuerpos de tamaño kilométrico) crecen a partir de granos de polvo, similares a los interestelares, embebidos en un disco gaseoso denominado nebulosa protoplanetaria. Durante esta etapa, los movimientos del gas pueden tener gran influencia en la dinámica y el crecimiento de los granos de polvo, dado que el flujo kepleriano del gas frena el movimiento de los mismos haciendo que caigan hacia el Sol, y la turbulencia inhibe la inestabilidad gravitacional de la capa de polvo. Aunque se acepta que los planetesimales fueron los elementos constituyentes de los planetas, todavía se desconoce cómo se produjo la formación de los mismos. Por esta razón, en los estudios más recientes, existe un renovado interés por comprender mejor la evolución de la capa de polvo inmersa en el disco gaseoso de la Nebulosa. El gas que fluye en el disco puede engendrar estructuras carentes de simetría axial, como por ejemplo ondas espirales y vórtices, a partir de gran variedad de mecanismos de excitación e inestabilidad. En 1995, Barge y Sommeria pusieron de manifiesto que la existencia de vórtices gaseosos persistentes en la nebulosa solar tendría importantes consecuencias sobre la formación de los planetesimales y el posterior crecimiento de los planetas gigantes. La investigación desarrollada en esta Tesis analiza la relación entre el polvo y el gas debida al acoplamiento por fricción dinámica entre ambos; en concreto, se estudia el efecto del flujo medio del gas sobre la dinámica de las partículas de polvo. El primer objetivo es investigar en profundidad los procesos de captura y crecimiento de los granos de polvo dentro de un vórtice y su posible relevancia en cuanto a la formación de los planetesimales. El segundo objetivo es la exploración de los efectos de ondas espirales propagándose en el disco gaseoso sobre la dinámica y el crecimiento de las partículas. La presencia de líneas de 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.

  9. [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

    Introducción: el entrenamiento mediante ejercicio físico moderado durante el periodo de gestación aporta beneficios tanto a la mujer embarazada como al feto. Los trabajos de investigación consultados vinculan la actividad física con una reducción del número de cesáreas, de partos instrumentados y con un parto más fisiológico. Previene igualmente la ganancia excesiva de peso de la mujer, disminuye el riesgo de diabetes gestacional y de hipertensión arterial.Objetivo: el objetivo de esta investigación es conocer si un programa de ejercicio físico de carácter moderado con el método Study Water Exercise Pregnant (SWEP), realizado en un medio acuático, contribuye a obtener unos resultados más favorables en la etapa perinatal, tanto para la mujer como para el bebé.Material y métodos: el diseño que se llevará a cabo es un ensayo clínico aleatorizado. La muestra estará constituida por 364 gestantes, obtenida de un universo total de 6.579 partos acontecidos en Granada (España) durante el año 2014. Dicha muestra se ha dividido en dos grupos, uno de intervención y otro de control. La actividad se realizará en las instalaciones deportivas acuáticas de la Facultad de Ciencias del Deporte de la Universidad de Granada, que cuentan con dos vasos adecuados a nuestros objetivos, uno polivalente de 25 metros y otro de enseñanza de 12,5 metros.  Resultados: el programa de ejercicios diseñado específicamente para el proyecto denominado SWEP, abarca desde la 20 hasta la 37 semana de gestación (SG) y consta de tres sesiones semanales, con una duración de 60 minutos cada una. Las sesiones incluirán tres fases: fase de calentamiento, fase principal en la que el ejercicio se divide en una parte aeróbica y otra de ejercicios de fuerza y resistencia y una final con estiramientos y relajación. Las variables que se van a estudiar son las siguientes: a) maternas: peso, IMC, tensión arterial, test de O´Sullivan, aparición de depresión postparto, 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

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

    NASA Astrophysics Data System (ADS)

    Maddock, Thomas, III.; Vionnet, Leticia Beatriz

    "Capture" is the increase in recharge and the decrease in discharge that occurs when pumping is imposed on an aquifer system that was in a previous state of approximate dynamic equilibrium. Regional groundwater models are usually used to calculate capture in a two-step procedure. A steady-state solution provides an initial-head configuration, a set of flows through the boundaries for the modeled region, and the initial basis for the capture calculation. The transient solutions provide the total change in flows through the boundaries. A difference between the transient and steady-state solutions renders the capture calculation. When seasonality is a modeling issue, the use of a single initial hydraulic head and a single set of boundary flows leads to miscalculations of capture. Instead, an initial condition for each season should be used. This approach may be accomplished by determining steady oscillatory solutions, which vary through the seasons but repeat from year to year. A regional groundwater model previously developed for a portion of the San Pedro River basin, Arizona, USA, is modified to illustrate the effect that different initial conditions have on transient solutions and on capture calculations. Résumé Les "prélèvements" sont constitués par l'augmentation de la recharge et par la diminution de l'écoulement qui se produit lorsqu'un pompage est imposéà un système aquifère qui était auparavant dans un état proche de l'équilibre dynamique. Les modèles régionaux de nappe sont en général utilisés pour calculer les prélèvements dans une procédure à deux étapes. Une solution en régime permanent donne la configuration piézométrique initiale, un jeu de conditions aux limites pour la région modélisée et les données de base pour le calcul des prélèvements. Les solutions transitoires donnent les modifications globales des conditions aux limites. Lorsque des variations saisonnières sont produites en sortie du modèle, le recours à une 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 captura.

  11. The conceptualization model problem—surprise

    NASA Astrophysics Data System (ADS)

    Bredehoeft, John

    2005-03-01

    The foundation of model analysis is the conceptual model. Surprise is defined as new data that renders the prevailing conceptual model invalid; as defined here it represents a paradigm shift. Limited empirical data indicate that surprises occur in 20-30% of model analyses. These data suggest that groundwater analysts have difficulty selecting the appropriate conceptual model. There is no ready remedy to the conceptual model problem other than (1) to collect as much data as is feasible, using all applicable methods—a complementary data collection methodology can lead to new information that changes the prevailing conceptual model, and (2) for the analyst to remain open to the fact that the conceptual model can change dramatically as more information is collected. In the final analysis, the hydrogeologist makes a subjective decision on the appropriate conceptual model. The conceptualization problem does not render models unusable. The problem introduces an uncertainty that often is not widely recognized. Conceptual model uncertainty is exacerbated in making long-term predictions of system performance. C'est le modèle conceptuel qui se trouve à base d'une analyse sur un modèle. On considère comme une surprise lorsque le modèle est invalidé par des données nouvelles; dans les termes définis ici la surprise est équivalente à un change de paradigme. Des données empiriques limitées indiquent que les surprises apparaissent dans 20 à 30% des analyses effectuées sur les modèles. Ces données suggèrent que l'analyse des eaux souterraines présente des difficultés lorsqu'il s'agit de choisir le modèle conceptuel approprié. Il n'existe pas un autre remède au problème du modèle conceptuel que: (1) rassembler autant des données que possible en utilisant toutes les méthodes applicables—la méthode des données complémentaires peut conduire aux nouvelles informations qui vont changer le modèle conceptuel, et (2) l'analyste doit rester ouvert au fait 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.

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

    NASA Astrophysics Data System (ADS)

    Misstear, Bruce D. R.; Beeson, Sarah

    The reliable yield of a water-supply well depends on many different factors, including the properties of the well and the aquifer; the capacities of the pumps, raw-water mains, and treatment works; the interference effects from other wells; and the constraints imposed by ion licences, water quality, and environmental issues. A relatively simple methodology for estimating reliable yields has been developed that takes into account all of these factors. The methodology is based mainly on an analysis of water-level and source-output data, where such data are available. Good operational data are especially important when dealing with wells in shallow, unconfined, fissure-flow aquifers, where actual well performance may vary considerably from that predicted using a more analytical approach. Key issues in the yield-assessment process are the identification of a deepest advisable pumping water level, and the collection of the appropriate well, aquifer, and operational data. Although developed for water-supply operators in the United Kingdom, this approach to estimating the reliable yields of water-supply wells using operational data should be applicable to a wide range of hydrogeological conditions elsewhere. Résumé La productivité d'un puits capté pour l'adduction d'eau potable dépend de différents facteurs, parmi lesquels les propriétés du puits et de l'aquifère, la puissance des pompes, le traitement des eaux brutes, les effets d'interférences avec d'autres puits et les contraintes imposées par les autorisations d'exploitation, par la qualité des eaux et par les conditions environnementales. Une méthodologie relativement simple d'estimation de la productivité qui prenne en compte tous ces facteurs a été mise au point. Cette méthodologie est basée surtout sur une analyse des données concernant le niveau piézométrique et le débit de prélèvement, quand ces données sont disponibles. De bonnes données opérationnelles sont particulièrement 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.

  13. 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

    One-third of the population of Oman depends upon groundwater extracted from the alluvium of the Batinah Plain, on the coast of the Gulf of Oman. Deep geophysical exploration techniques were used to determine the depth and nature of the alluvium and the boundaries of the aquifer. The base and structural controls of the alluvial basin at its contact with Tertiary marine sediments and Cretaceous ophiolite were mapped with seismic reflection data, recorded originally for oil exploration. The base of the alluvium dips northward from the foothills of the Northern Oman Mountains, reaching a maximum depth of 2000m at the coast. The varying facies of the alluvium are grossly characterised by different, overlapping ranges of electrical resistivity, depending largely on the clay content and degree of cementation. Resistivities near the coast are reduced by saline intrusion. These variations of resistivity were mapped with time-domain electromagnetic sounding along 400km of profile, to distinguish among the three zones of the alluvial aquifer. The wedge of saline intrusion was also delineated, up to 10km from the coast. The thickness of the saturated gravel aquifer ranges from 20-160m in an area greater than 600km2. Résumé Un tiers de la population d'Oman est alimenté par de l'eau souterraine pompée dans les alluvions de la plaine de Batinah, sur la côte du golfe d'Oman. Des techniques d'exploration géophysique profonde ont été mises en oeuvre pour déterminer la profondeur et la nature des alluvions et les limites de l'aquifère. La base et les contrôles structuraux du bassin alluvial au contact des sédiments marins tertiaires et des ophiolites crétacées ont été cartographiés à partir des données de sismique réflexion obtenues à l'origine pour la recherche pétrolière. La base des alluvions plonge vers le nord à partir du piémont du massif septentrional d'Oman, pour atteindre une profondeur maximale de 2000m sur la côte. Les divers faciès alluviaux 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.

  14. 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

    Objectives To evaluate the feasibility (population reached, costs) and effectiveness (positivity rates, linkage to care) of two strategies of community-based HIV testing and counselling (HTC) in rural Swaziland. Methods Strategies used were mobile HTC (MHTC) and home-based HTC (HBHTC). Information on age, sex, previous testing and HIV results was obtained from routine HTC records. A consecutive series of individuals testing HIV-positive were followed up for 6 months from the test date to assess linkage to care. Results A total of 9 060 people were tested: 2 034 through MHTC and 7 026 through HBHTC. A higher proportion of children and adolescents (<20 years) were tested through HBHTC than MHTC (57% vs. 17%; P < 0.001). MHTC reached a higher proportion of adult men than HBHTC (42% vs. 39%; P = 0.015). Of 398 HIV-positive individuals, only 135 (34%) were enrolled in HIV care within 6 months. Of 42 individuals eligible for antiretroviral therapy, 22 (52%) started treatment within 6 months. Linkage to care was lowest among people who had tested previously and those aged 20–40 years. HBHTC was 50% cheaper (US$11 per person tested; $797 per individual enrolled in HIV care) than MHTC ($24 and $1698, respectively). Conclusion In this high HIV prevalence setting, a community-based testing programme achieved high uptake of testing and appears to be an effective and affordable way to encourage large numbers of people to learn their HIV status (particularly underserved populations such as men and young people). However, for community HTC to impact mortality and incidence, strategies need to be implemented to ensure people testing HIV-positive in the community are linked to HIV care. Objectifs Evaluer la faisabilité (population atteinte, coûts) et l'efficacité (taux de positivité, liaison aux soins) de deux stratégies de dépistage et conseil (DC) communautaire du VIH en zone rurale au Swaziland. Méthodes Les stratégies utilisées étaient des DC mobiles (DC-M) et le DC à domicile (DC-D). Les informations sur l’âge, le sexe, les tests précédents et les résultats VIH ont été obtenues à partir des dossiers de routine du DC. Une série d'individus séropositifs consécutifs a été suivie pendant six mois à partir de la date du test afin d’évaluer les liaisons aux soins. Résultats 9.060 personnes ont été testées: 2.034 par le biais du DC-M et 7026 par le biais du DC-D. Une plus grande proportion d'enfants et d'adolescents (<20 ans) ont été testés par le biais du DC-D que par celui du DC-M (57% vs 17%; p <0,001). Le DC-M a atteint une proportion plus élevée d'hommes adultes que le DC-D (42% vs 39%; p = 0,015). Des 398 personnes séropositives, seules 135 (34%) ont été inscrites à des soins VIH dans les 6 mois. De 42 personnes admissibles à la thérapie antirétrovirale, 22 (52%) ont commencé le traitement dans les 6 mois. Les liaisons avec les soins étaient plus faibles chez les personnes qui ont effectué un dépistage auparavant et celles âgées de 20 à 40 ans. Le DC-D était 50% moins cher (11 $ US par personne testée, 797 $ par personne inscrite dans les soins VIH) que le DC-M (24 $ et 1.698 $, respectivement). Conclusion Dans ce contexte à haute prévalence du VIH, un programme de dépistage communautaire a atteint une couverture élevée et semble être un moyen efficace et abordable pour encourager un grand nombre de personnes à connaître leur statut VIH (en particulier les populations mal desservies, telles que les hommes et les jeunes personnes). Cependant, afin que le DC communautaire ait un impact sur la mortalité et l'incidence, des stratégies doivent être mises en œuvre pour assurer que les personnes testées séropositives dans la communauté soient reliées aux soins du VIH. Objetivos Evaluar la viabilidad (población alcanzada, costes) y efectividad (tasas de positividad, vinculación al tratamiento) de dos estrategias comunitarias de asesoramiento y prueba para el VIH (APV) 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 estrategias apoyen el tratamiento, asegurando que las personas que dan positivo en la prueba son remitidas y reciben los cuidados adecuados. PMID:25753897

  15. 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

    Objective To evaluate services in hospitals providing internship training to graduate doctors in Kenya. Methods A survey of 22 internship training hospitals was conducted. Availability of key resources spanning infrastructure, personnel, equipment and drugs was assessed by observation. Outcomes and process of care for pre-specified priority conditions (head injury, chest injury, fractures, burns and acute abdomen) were evaluated by auditing case records. Results Each hospital had at least one consultant surgeon. Scheduled surgical outpatient clinics, major ward rounds and elective (half day) theatre lists were provided once per week in 91%, 55% and 9%, respectively. In all other hospitals, these were conducted twice weekly. Basic drugs were not always available (e.g. gentamicin, morphine and pethidine in 50%, injectable antistaphylococcal penicillins in 5% hospitals). Fewer than half of hospitals had all resources needed to provide oxygen. One hundred and forty-five of 956 cases evaluated underwent operations under general or spinal anaesthesia. We found operation notes for 99% and anaesthetic records for 72%. Pre-operatively measured vital signs were recorded in 80% of cases, and evidence of consent to operation was found in 78%. Blood loss was documented in only one case and sponge and instrument counts in 7%. Conclusions Evaluation of surgical services would be improved by development and dissemination of clear standards of care. This survey suggests that internship hospitals may be poorly equipped and documented care suggests inadequacies in quality and training. Objectif Evaluer les services dans les hôpitaux offrant des stages de formation à des médecins diplômés au Kenya. Méthodes Enquête auprès de 22 hôpitaux offrant des stages de formation. La disponibilité des ressources clés incluant infrastructure, personnel, matériel et médicaments a été évaluée par observation. Les résultats et processus de soins pour des affections prioritaires prédéfinies (blessure à la tête, blessure à la poitrine, fractures, brûlures et maux d'estomac aigus) ont été évalués par l'audit des dossiers des cas. Résultats Chaque hôpital avait au moins un chirurgien consultant. Les cliniques chirurgicales ambulatoires planifiées, les principales tournées dans les chambres d'hospitalisation et des listes d'opérations choisies (demi-journée) ont été fournies une fois par semaine dans 91%, 55% et 9% des cas respectivement. Dans tous les autres hôpitaux, cela a été effectué deux fois par semaine. Les médicaments de base n’étaient pas toujours disponibles (par ex. la gentamicine, la morphine et la péthidine dans 50% des hôpitaux, les pénicillines anti-staphylococciques injectables dans 5%). Moins de la moitié des hôpitaux disposaient de toutes les ressources nécessaires pour fournir de l'oxygène. 145 sur 956 cas évalués ont subi des opérations sous anesthésie générale ou rachidienne. Nous avons retrouvé des notes d'opération pour 99% des cas et des dossiers d'anesthésie pour 72%. Les mesures préopératoires des signes vitaux ont été enregistrées dans 80% des cas et la preuve du consentement pour l'opération a été trouvée dans 78% des cas. La perte de sang a été documentée dans un seul cas et le comptage des éponges et instruments dans 7% des cas. Conclusions L’évaluation des services de chirurgie serait améliorée par le développement et la dissémination de normes de soins claires. Cette étude suggère que les hôpitaux offrant des stages peuvent être mal équipés et les soins enregistrés suggèrent des insuffisances dans la qualité et la formation. Objetivo Evaluar los servicios en hospitales que proveen entrenamiento a médicos graduados en Kenia. Métodos Estudio en 22 hospitales universitarios con entrenamiento de médicos residentes. Se evaluó mediante observación la disponibilidad de recursos claves, incluyendo infraestructura, personal, equipamiento y medicamentos. Se evaluaron 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