66 research outputs found
"Cervia Working Group Report" : guidelines on the diagnosis and treatment of Helicobacter pylori infection
No full textDifferent national attitudes exist between countries in Europe concerning eradication of Helicobacter pylori infection due to the wide differences in Helicobacter pylori prevalence, gastric cancer risk, bacterial resistance to antibiotics, health care systems and financial resources. The Cervia Working Group Report has been established in order to fill the gap in the absence of National Guidelines in Italy concerning the diagnosis and treatment of Helicobacter pylori infection. The recommendations made are, by and large, similar to the European Guidelines but differ slightly with regard to the "test-and-treat" approach to young dyspeptics without sinister symptoms. In the absence of a national validation of this strategy a case-by-case assessment of dyspepsia has been promoted, both at primary care and specialist level. Another area of partial disagreement concerns the eradication of Helicobacter pylori in patients undergoing long-term proton pump inhibitor treatment which has not been generally recommended as scientific evidence in support of this policy is at present rather weak
A controlled study of the effects of mental relaxation on autonomic excitatory responses in healthy subjects
No full textObjective: Circumstantial evidence indicates that, in the presence of a suitable substratum, sudden, behaviorally induced increases in sympathetic drive to the cardiovascular system might play an important physiopathological role in various conditions, ranging from arterial hypertension to sudden coronary death. Accordingly, it might be useful to study the effects of behavioral interventions, such as mental relaxation, that might be capable of blunting excitatory autonomic responses. It would also be preferable to study healthy subjects in whom autonomic control is not modified by the presence of disease, and to use noninvasive approaches to minimize the possible emotional impact produced by invasive recordings. Methods: We examined healthy subjects who were either subjected to relaxation training (N = 13) or sham relaxation (N = 12). An additional group, treated with β-adrenergic blockade (N = 12), was also examined. Spectral and cross-spectral analysis of RR interval and systolic arterial pressure (SAP) variabilities provided quantitative markers of sympathovagal balance modulating the sineatrial (SA) node, of sympathetic vasomotor modulation, and of the gain of the arterial pressure/heart period baroreflex (index α). Subjects were studied at rest, during standing, and during mental arithmetic. Results: Data indicate that both β-adrenergic blockade and relaxation training significantly blunted the excitatory autonomic responses to standing and to mental arithmetic. Indices of sympathetic modulation also seemed reduced by β blockade at rest. No changes were observed with sham training. Conclusions: Frequency domain analysis of cardiovascular variabilities, using a totally noninvasive approach, indicates that relaxation training significantly blunts the excitatory autonomic changes produced by standardized behavioral laboratory stimuli
Streptococcus pneumoniae induces mast cell degranulation
No full textStreptococcus pneumoniae colonizes the nasopharynx of healthy human carriers, but occasionally can spread in the body causing severe diseases. The mucosa of the respiratory tract is enriched in mast cells, key players of the innate immune response. Here, we report on the interaction of various strains of S. pneumoniae with the mast cell line RBL-2H3. Live, but not heat-killed, bacteria were found to induce mast cell degranulation in a dose- and time-dependent manner, only partially controlled by cytosolic calcium, with no production of TNF-alpha and IL-6. Non-encapsulated pneumococcal strains exhibited different potencies in triggering mast cells. We propose here that the induction of mast cell degranulation by pneumococcal factors not accompanied by the production of pro-inflammatory cytokines may be a specific strategy elaborated by this bacterium to promote its own spreading from the respiratory mucosa into the environment
"Cervia Working Group Report": Guidelines on the diagnosis and treatment of Helicobacter pylori infection
No full textDifferent national attitudes exist between countries in Europe concerning eradication of Helicobacter pylori infection due to the wide differences in Helicobacter pylori prevalence, gastric cancer risk, bacterial resistance to antibiotics, health care systems and financial resources. The Cervia Working Group Report has been established in order to fill the gap in the absence of National Guidelines in Italy concerning the diagnosis and treatment of Helicobacter pylori infection. The recommendations made are, by and large, similar to the European Guidelines but differ slightly with regard to the "test-and-treat" approach to young dyspeptics without sinister symptoms. In the absence of a national validation of this strategy a case-by-case assessment of dyspepsia has been promoted, both at primary care and specialist level. Another area of partial disagreement concerns the eradication of Helicobacter pylori in patients undergoing long-term proton pump inhibitor treatment which has not been generally recommended as scientific evidence in support of this policy is at present rather weak
Patients younger than 40 years with gastric carcinoma - Helicobacter pylori genotype and associated gastritis phenotype
No full textBACKGROUND: In the general population, Helicobacter pylori (H. pylori), particularly the cagA positive strain, has been associated with intestinal-type gastric carcinoma. Gastric carcinomas are rarely observed in patients age < or = 40 years. Host-related factors have been thought to be more important than environmental agents in these early-onset cancers. The aim of this study was to ascertain the possible role of H. pylori infection and that of cagA positive strains in the development of gastric carcinoma in these young patients.
METHODS: In this case-control study, 105 gastric carcinoma patients (male-to-female ratio = 1.1; mean age, 34.4 years; range, 16-40 years) and an equal number of controls (matched for gender and age) were retrospectively selected from the same geographic area. The phenotypes of gastritis and H. pylori were histologically assessed, and the presence of the ureC gene, which is indicative of H. pylori infection, and the cagA genotype were determined by polymerase chain reaction. Gastric carcinoma risk was calculated by both univariate and multivariate statistical methods, taking into account the cancer phenotype, the gastritis phenotype detected in both patients and controls, and the H. pylori genotype.
RESULTS: For 74 diffuse and 31 intestinal gastric carcinomas, multivariate logistic regression analysis produced results consistent with those of univariate statistical tests, showing a significant association between gastric carcinoma and both H. pylori infection (odds ratio [OR] = 2.79; 95% confidence interval [CI] = 1.52-5.11) and cagA positive status (OR = 2.94; 95% CI = 1.56-5.52).
CONCLUSIONS: In young Italian patients with gastric carcinoma, the significant association with cagA positive H. pylori infection suggests that the bacterium has an etiologic role in both diffuse-type and intestinal-type gastric carcinom
MOLECULAR CHARACTERIZATION OF THE 128-KDA IMMUNODOMINANT ANTIGEN OF HELICOBACTER-PYLORI-ASSOCIATED WITH CYTOTOXICITY AND DUODENAL-ULCER
No full textHelicobacter pylori has been associated with gastritis, peptic ulcer, and gastric adenocarcinoma. We report the nucleotide sequence and expression of an immunodominant antigen of H. pylori and the immune response to the antigen during disease. The antigen, named CagA (cytotoxin-associated gene A), is a hydrophilic, surface-exposed protein of 128 kDa produced by most clinical isolates. The size of the cagA gene and its protein varies in different strains by a mechanism that involves duplication of regions within the gene. Clinical isolates that do not produce the antigen do not have the gene and are unable to produce an active vacuolating cytotoxin. An ELISA to detect the immune response against a recombinant fragment of this protein detects 75.3% of patients with gastroduodenal diseases and 100% of patients with duodenal ulcer (P < 0.0005), suggesting that only bacteria harboring this protein are associated with disease
Molecular characterization H. pylori associated with cytotoxicity and duodenal ulcer
No full textHelicobacter pylori has been associated with gastritis, peptic ulcer, and gastric adenocarcinoma. We report the nucleotide sequence and expression of an immunodominant antigen of H. pylori and the immune response to the antigen during disease. The antigen, named CagA (cytotoxin-associated gene A), is a hydrophilic, surface-exposed protein of 128 kDa produced by most clinical isolates. The size of the cagA gene and its protein varies in different strains by a mechanism that involves duplication of regions within the gene. Clinical isolates that do not produce the antigen do not have the gene and are unable to produce an active vacuolating cytotoxin. An ELISA to detect the immune response against a recombinant fragment of this protein detects 75.3% of patients with gastroduodenal diseases and 100% of patients with duodenal ulcer (P < 0.0005), suggesting that only bacteria harboring this protein are associated with disease
Inter-species horizontal transfer resulting in core-genome and niche-adaptive variation within Helicobacter pylori
No full textBackground
Horizontal gene transfer is central to evolution in most bacterial species. The detection of exchanged regions is often based upon analysis of compositional characteristics and their comparison to the organism as a whole. In this study we describe a new methodology combining aspects of established signature analysis with textual analysis approaches. This approach has been used to analyze the two available genome sequences of H. pylori.
Results
This gene-by-gene analysis reveals a wide range of genes related to both virulence behaviour and the strain differences that have been relatively recently acquired from other sequence backgrounds. These frequently involve single genes or small numbers of genes that are not associated with transposases or bacteriophage genes, nor with inverted repeats typically used as markers for horizontal transfer. In addition, clear examples of horizontal exchange in genes associated with 'core' metabolic functions were identified, supported by differences between the sequenced strains, including: ftsK, xerD and polA. In some cases it was possible to determine which strain represented the 'parent' and 'altered' states for insertion-deletion events. Different signature component lengths showed different sensitivities for the detection of some horizontally transferred genes, which may reflect different amelioration rates of sequence components.
Conclusion
New implementations of signature analysis that can be applied on a gene-by-gene basis for the identification of horizontally acquired sequences are described. These findings highlight the central role of the availability of homologous substrates in evolution mediated by horizontal exchange, and suggest that some components of the supposedly stable 'core genome' may actually be favoured targets for integration of foreign sequences because of their degree of conservation
Sequencing, annotation, and comparative genome analysis of the gerbil-adapted Helicobacter pylori strain B8
No full textFarnbacher M, Jahns T, Willrodt D, et al. Sequencing, annotation, and comparative genome analysis of the gerbil-adapted Helicobacter pylori strain B8. BMC Genomics. 2010;11(1): 335.Background: The Mongolian gerbils are a good model to mimic the Helicobacter pylori-associated pathogenesis of the human stomach. In the current study the gerbil-adapted strain B8 was completely sequenced, annotated and compared to previous genomes, including the 73 supercontigs of the parental strain B128. Results: The complete genome of H. pylori B8 was manually curated gene by gene, to assign as much function as possible. It consists of a circular chromosome of 1,673,997 bp and of a small plasmid of 6,032 bp carrying nine putative genes. The chromosome contains 1,711 coding sequences, 293 of which are strain-specific, coding mainly for hypothetical proteins, and a large plasticity zone containing a putative type-IV-secretion system and coding sequences with unknown function. The cag-pathogenicity island is rearranged such that the cagA-gene is located 13,730 bp downstream of the inverted gene cluster cagB-cag1. Directly adjacent to the cagA-gene, there are four hypothetical genes and one variable gene with a different codon usage compared to the rest of the H. pylori B8-genome. This indicates that these coding sequences might be acquired via horizontal gene transfer. The genome comparison of strain B8 to its parental strain B128 delivers 425 unique B8-proteins. Due to the fact that strain B128 was not fully sequenced and only automatically annotated, only 12 of these proteins are definitive singletons that might have been acquired during the gerbil-adaptation process of strain B128. Conclusion Our sequence data and its analysis provide new insight into the high genetic diversity of H. pylori-strains. We have shown that the gerbil-adapted strain B8 has the potential to build, possibly by a high rate of mutation and recombination, a dynamic pool of genetic variants (e.g. fragmented genes and repetitive regions) required for the adaptation-processes. We hypothesize that these variants are essential for the colonization and persistence of strain B8 in the gerbil stomach during inflammation
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