Biomedical subjects

E N Mendes

Publications and source records attributed to E N Mendes.

At least 19 recordsLinked to original sources

PubMed2001

iceA genotypes of Helicobacter pylori strains isolated from Brazilian children and adults.

Data concerning the geographic distribution of iceA alleles are scarce, and information on the association of the gene with the disease is rare and still controversial. Furthermore, no such study has been developed in Brazil, where duodenal ulcer and gastric adenocarcinoma are very common. We investigated, by PCR, the frequency of iceA alleles and cagA status in Helicobacter pylori strains isolated from 142 patients (62 children and 80 adults; 66 female; mean age, 30.0 years; age range, 3 to 78 years) with gastritis, duodenal ulcer, or gastric adenocarcinoma. iceA was identified in bacterium samples obtained from all patients. Eleven (7.7%) of them were infected with multiple strains. Among the patients with nonmixed infection, iceA2 allele was detected in 118 (90.1%). iceA2 allele was associated with ulcer (P = 0.02) and with carcinoma (P = 0.001). iceA2 amplicons of 229, 334, or 549 bp were detected, but none of them was associated with the patient's disorder. iceA2 strains were more frequent in patients older than 7 years (P = 0.001). The gene was also more frequent in strains obtained from males (P = 0.02). cagA was more common in strains obtained from carcinoma (P = 0.0008) and ulcer patients (P < 0.006). cagA-positive strains were more frequent in children older than 7 years (P < 0.003). No association between cagA status and sex was found (P = 0.28). In conclusion, we think iceA should not be used as a reliable marker for predicting the clinical outcome of H. pylori infection.

Adolescent↗

PubMed2000

Factors associated with Helicobacter pylori infection by a cagA-positive strain in children.

Although infection with a cagA-positive Helicobacter pylori strain is considered a risk factor for the development of duodenal peptic ulcer in adults, this association has not been demonstrated in children. The presence of cagA was investigated by polymerase chain reaction in H. pylori strains isolated from 27 children with duodenal ulcer and 53 without duodenal ulcer. All patients (100%) with duodenal ulcer and 33 (62.3%) without ulcer were colonized by a cagA-positive strain (P=.00007). A cagA-positive status was also associated with a more marked macroscopic gastritis, with a greater inflammatory infiltrate of both mononuclear and polymorphonuclear cells in the antral and oxyntic gastric mucosae and degenerative and regenerative changes of the gastric mucosa. Increased cagA positivity was also associated with increased age, but no association between cagA-positive status and sex was observed.

Adolescent↗

PubMed2000

'Flexispira rappini' strains represent at least 10 Helicobacter taxa.

'Flexispira rappini' is a provisional name given to gram-negative, microaerophilic, motile, spindle-shaped micro-organisms with spiral periplasmic fibres and bipolar tufts of sheathed flagella. Several investigators, including Kirkbride, Romero, and Archer isolated strains possessing this morphology. Previously, the phylogenetic position of three 'Flexispira rappini' strains was determined by 165 rRNA sequencing, which indicated that flexispira were members of the genus Helicobacter. As more organisms with 'F. rappini' morphology were isolated, it became apparent that there were multiple Helicobacter taxa with this distinctive morphology. The purpose of this study was to examine a collection of 36 'F. rappini' strains from diverse habitats by using 165 rRNA sequence analysis. The strains fell into 10 taxa, each possibly representing a novel Helicobacter species. Two of these flexispira taxa were previously named, by us, Helicobacter bilis and Helicobacter trogontum. Currently, none of the flexispira taxa contains enough phenotypically and genotypically characterized strains to be formally named 'Helicobacter rappinii'.

Animals↗

PubMed2000

[Human care: purification action].

This article was originated by a request of some professors of the Masters Course in Nursing. The theme "bath", as an act of care, was developed, initially, on the meaning of moves. The esthetic of body movement, to the sound of music, was represented graphically, allowing to reach constructs as: relationship, physical contact, sharing, pleasure, satisfaction, cleanliness, reaproximation. The concept of "bath", understood through research in different bibliography and idioms, was translated as "purification". The meaning of "purification" was studied with an anthropological view. Many practices and rituals were perceived through history and human experience and bring with them tools that may help Nursing to create and recreate the experience and concept of human care. These elements and some contributions to comprehend care are shown in this study.

Baths↗

PubMed1999

Microbiological and histological study of the gastrointestinal tract of germ-free mice infected with Helicobacter trogontum.

Helicobacter spp. have been the focus of considerable research because of the role of this genus in gastrointestinal diseases. We infected NIH germ-free mice with Helicobacter trogontum, a recently described intestinal bacterium of rats, in order to study the distribution of this bacterium in the gastrointestinal tract and the histopathological changes it can induce in this host. Sixteen mice were challenged with a single dose of H. trogontum (test group) and killed one and six weeks after inoculation (eight animals at each point). Eight animals were challenged with 0.85% saline alone (control group) and killed at the same time points (four at each point). Fragments from the gastric and intestinal mucosa were obtained for microbiological and histological examination. H. trogontum was isolated from the cecum and colon of all test mice and also from the gastric mucosa of several of them. All infected animals presented histological changes in at least one region of the bowel. Alterations in the gastric mucosa were also observed mainly in the six-week-infected group. The predominant histological change observed was a moderate diffuse inflammatory infiltrate of mononuclear cells in the lamina propria, often accompanied by a mild infiltration of polymorphonuclear cells. Two animals presented focal infiltration of inflammatory cells in the liver, although no bacteria were found in the liver of any animal. H. trogontum is an intestinal species that is able to elicit inflammatory responses in other regions of the gastrointestinal tract such as the gastric mucosa and the liver of gnotobiotic mice.

Animals↗

PubMed1999

Differences among Helicobacter pylori strains isolated from three different populations and demonstrated by restriction enzyme analysis of an internal fragment of the conserved gene hpaA.

BACKGROUND: Our goal was to test the idea that Helicobacter pylori genotypes vary from one population to another. METHODS: Analysis of Sau3A and HinfI restriction fragment-length polymorphism (RFLP) in a 375-bp polymerase chain reaction amplicon of hpaA was used to compare 31 H. pylori isolates from a relatively small and genetically homogeneous population (Goteborg, Sweden) with those of large, genetically heterogeneous populations located in two different countries (50 isolates from Houston, TX, and 69 isolates from Minas Gerais, a state in the southeastern region of Brazil). RESULTS: Five different Sau3A and three different HinfI restriction patterns were found; different combinations of these comprise 10 different RFLP types, I through X. The RFLP types found in the United States and Brazil collections were very similar, except for two Brazil isolates belonging to type VIII and five Brazil isolates belonging to type X, neither type found in the United States. The overall profile of H. pylori isolates from Sweden was remarkably different, with 18 of 31 (58%) having a new Sau3A restriction pattern, termed gS; 10 of these 18 isolates had HinfI restriction pattern E (RFLP type VIII), and 8 had HinfI restriction pattern F (RFLP type IX). No isolates from Sweden belonged to RFLP type III or type X. CONCLUSIONS: RFLP typing of a 375-bp polymerase chain reaction-amplified DNA fragment of H. pylori hpaA revealed that H. pylori genotypes can and do vary from one population to another. We conclude that the unique RFLP profile shown by the group of H. pylori isolates from Goteborg is the result of a cohort effect in this relatively small, stable, genetically homogeneous population. Also, the overall similarity between RFLP profiles of the H. pylori isolates from Texas and Minas Gerais coincides with the fact that although geographically distanced, these populations are similar in being large, dynamic, and genetically heterogeneous.

Adhesins, Bacterial↗

PubMed1999

Evaluation of enzyme-linked immunosorbent assay for the diagnosis of Helicobacter pylori infection in children from different age groups with and without duodenal ulcer.

BACKGROUND: Although enzyme-linked immunosorbent assay (ELISA) is highly sensitive and specific for the diagnosis of Helicobacter pylori infection in adults, their performance in children is still controversial. METHODS: A second-generation ELISA was used to evaluate the IgG response to H. pylori in the serum of 130 consecutive children who underwent upper gastrointestinal endoscopy. The presence of H. pylori was determined in antral biopsy specimens by culture, urease test, and histologic analysis. RESULTS: Sixty-eight children (all of the 20 who had duodenal ulcer) were H. pylori positive by microbiologic test. Immunoglobulin G antibodies to H. pylori were detected in 79.4% of the infected children and in 8.1% of the noninfected ones. The sensitivity of the test was higher in patients with duodenal ulcer (100%) than in those without (70.8%). When used in children of different ages the test also presented differences in sensitivity: 44.4% in children 2 to 6 years old; 76.7% in children 7 to 11 years old, and 93.1% in children 12 to 16 years old (p = 0.006). The serum immunoglobulin G concentration was significantly higher (p = 0.0003) in children with duodenal ulcer than in those without and was higher in older children than in younger ones without duodenal ulcer (p = 0.05). CONCLUSIONS: The accuracy of the test in children with duodenal ulcer and in children more than 12 years old was good; however, in children up to 12 years of age without duodenal ulcer, the sensitivity of the test was too low to be used for screening purposes or to rule out the presence of infection.

Adolescent↗

PubMed1998

cagA-positive Helicobacter pylori and risk for developing gastric carcinoma in Brazil.

To evaluate a possible association between infection with cag A-positive strains and gastric carcinoma increased risk we studied 119 Helicobacter pylori-positive patients with gastric carcinoma and 119 matched controls. The presence of cag A gene was investigated by PCR in H. pylori isolates and in gastric biopsy specimens. A significant association was found between cag A-positive status and distal gastric carcinoma for both the intestinal and diffuse types of tumor for both males and females. On the other hand, no association was observed between cag A-positive status and proximal gastric carcinoma.

Adult↗

PubMed1998

Diversity in the variable region of Helicobacter pylori cagA gene involves more than simple repetition of a 102-nucleotide sequence.

CagA, a product of cytotoxin-associated gene A cagA, is an important virulence-related antigen of Helicobacter pylori (HP). CagA varies in size from 128 kDa to about 140 kDa and this variation is believed to be generated by a 102-nucleotide (NT) repeat sequence in the so-called variable region of cagA. However, this explanation has not previously been tested by comparing the NT sequences of cagA derived from a number of different isolates of HP. In this study we first compared the size of PCR products obtained from 54 different isolates of HP with oligonucleotide primers designed to amplify a cagA fragment predicted to be at least 1059 NT, including the variable region of the gene. As expected, the size of the PCR products varied considerable, from 1110 to 1822 NT, but the majority (50 of 54) measured 1335 NT or less. The deduced amino acid (AA) sequences of 9 representative amplicons and 4 other known sequences were compared with the following result: Within the variable region of cagA there are actually two adjacent variable regions, which we label as proximal and distal. The proximal-variable region of CagA extends from a motif of 4 to 6 asparagine residues to a 7-AA repeat sequence (KIDQLNQ); the distal-variable region is confined between KIDQLNQ and a well-conserved duplicate, KIDNLNQ. Despite these shared features CagA of every HP strain examined to date has a variable region with a unique AA sequence.

Amino Acid Sequence↗

PubMed1998

Ultrastructure of Helicobacter trogontum in culture and in the gastrointestinal tract of gnotobiotic mice.

Helicobacter trogontum is a micro-aerophilic urease-positive bacterium that has recently been isolated from the intestinal mucosa of rats. The purpose of this investigation was to study the ultrastructural details of this micro-organism in both pure culture and in the gastrointestinal tract of germ-free mice infected with H. trogontum. The micro-organism was a fusiform to slightly spiral gram-negative cell, 4-6 microm long and 0.6-0.7 microm wide, with four to seven bipolar sheathed flagella. The cytoplasm presented several irregular and also globular granules. On each side of the polar regions of the cells, there was a highly electron-dense band, the 'polar membrane'. Coccoidal forms were seen in old cultures. H. trogontum showed several ultrastructural characteristics of the Helicobacter genus and much resemblance to H. rappini and H. bilis. H. trogontum mainly colonised the large bowel of the gnotobiotic mice where it could be seen in the lumen and also inside the enterocytes. Vacuolation of the ileal epithelial cells, loss of microvilli and pronounced desquamation of the enterocytes of the caecum were observed in the bowel colonised by the bacterium. These observations raise the possibility that H. trogontum could cause some harm to the host at least in particular circumstances such as when it colonises the gastrointestinal tract of a germ-free host.

Animals↗

PubMed1998

The interrelationship between Helicobacter pylori vacuolating cytotoxin and gastric carcinoma.

OBJECTIVE: We aimed to determine whether cytotoxin-positive Helicobacter pylori strains are associated with gastric carcinoma. METHODS: We studied 130 patients: 57 H. pylori-positive patients with gastric carcinoma, 53 H. pylori-positive patients without gastric carcinoma, and 20 H. pylori-negative subjects. The ability of H. pylori strains to produce vacuolating cytotoxin was tested in INT-407 and HeLa cells. The presence of antibodies to cytotoxin was investigated in blood serum from all subjects by immunoblotting. Fragments of the gastric mucosa from patients without gastric carcinoma and H. pylori-negative subjects were obtained for histopathological study. RESULTS: Considering the results as a whole, 40 (70.2%) patients with and 22 (41.5%) without gastric carcinoma were colonized by cytotoxin-positive strains. Antibodies against cytotoxin were not observed in the serum from 17 (29.8%) gastric carcinoma patients and from 31 (58.5%) patients without gastric carcinoma. H. pylori strains isolated from these patients did not produce cytotoxin in vitro. In regard to cytotoxin positivity, a significant difference was observed between patients with and without gastric carcinoma (p=0.004; odds ratio [OR]: 3.3; 95% confidence interval [CI]: 1.4-7.9). Higher scores of mononuclear (p=0.0001) and polymorphonuclear (p=0.000003) cells were observed in the antral mucosa from H. pylori-positive patients without gastric carcinoma infected by cytotoxin-positive strains than in those harboring cytotoxin-negative strains. CONCLUSION: Cytotoxin-producing H. pylori strains were more frequently observed in patients with gastric carcinoma and this aspect emphasizes the role of cytotoxin in the genesis of the tumor.

Antibodies, Bacterial↗

PubMed1998

Helicobacter pylori cagA status and s and m alleles of vacA in isolates from individuals with a variety of H. pylori-associated gastric diseases.

The cagA gene was detected in 100% of 16 Helicobacter pylori isolates from patients with gastric carcinoma versus 78% of 18 isolates from patients with duodenal ulcers (P = 0.344) and only 64% of 22 isolates from patients with gastritis only (P = 0.005) in Brazil. Also, there was a significant association between isolation of cagA+ s1-type vacA H. pylori in cases of stomach cancer and ulcers as opposed to cases of gastritis only (P = 0.004), but this was not true in Houston (P = 0.238), where 94% of all isolates were cagA+.

Alleles↗

PubMed1998

Mouse inoculation for the detection of non-cultivable gastric tightly spiralled bacteria.

In the present study we compared the inoculation of swine gastric mucus into the stomach of mice, the ureas test and carbolfuchsin-stained smears for the diagnosis of the infection with "Gastrospirillum suis" ("Helicobacter heilmannii" type 1), an uncultivated tightly spiralled gastric bacterium. Fragments obtained from the antral and oxyntic mucosa of the stomach of 50 slaughtered pigs were used for urease test, for carbolfuchsin-stained smears and for obtaining scrapings of mucus for mouse inoculation. The mice were killed by spinal dislocation 10 days after inoculation and fragments of the antral and oxyntic mucosa were used for spiral bacterium identification (urease test and carbolfuchsin-stained smears). Among the methods employed for the diagnosis of "H. heilmannii" infection, the inoculation of gastric mucus into the stomach of mice was the most sensitive and demonstrated bacterial positivity in 31 (62.0%) swine. Direct examination showed tightly spiralled bacteria in the gastric mucosa of only 4 (8.0%) of the 50 pigs studied. Among them, 3 (6.0%) presented a positive preformed urease test. Spiral bacteria were not seen in the gastric mucosa of any control mice. These results show that the use of the mouse inoculation method improved the detection of "H. heilmannii" in swine.

Animals↗

PubMed1998

Serodiagnosis of Helicobacter pylori infection by Cobas Core ELISA in adults from Minas Gerais, Brazil.

We evaluated the accuracy of a 2nd generation ELISA to detect Helicobacter pylori infection in adults from a developing country in view of variations in sensitivity and specificity reported for different populations. We studied 97 non-consecutive patients who underwent endoscopy for evaluation of dispeptic symptoms. The presence of H. pylori was determined in antral biopsy specimens by culture, by the preformed urease test and in carbolfuchsin-stained smears. Patients were considered to be H. pylori positive if at least two of the three tests presented a positive result or if the culture was positive, and negative if the three tests were negative. Sixty-five adults (31 with peptic ulcer) were H. pylori positive and 32 adults were H. pylori negative. Antibodies were detected by Cobas Core anti-H. pylori EIA in 62 of 65 H. pylori-positive adults and in none of the negative adults. The sensitivity, specificity and positive and negative predictive values of the test were 95.4, 100, 100 and 91.4%, respectively. The Cobas Core anti-H. pylori EIA presented high sensitivity and specificity when employed for a population in Brazil, permitting the use of the test both to confirm the clinical diagnosis and to perform epidemiologic surveys.

Adult↗

PubMed1996

Association between Helicobacter and gastric ulcer disease of the pars esophagea in swine.

BACKGROUND & AIMS: Swine present spontaneously peptic ulcer in the gastric pars esophagea and are frequently colonized by a spiral bacterium that is of the same species as Helicobacter heilmannii type 1. This organism is also observed in the gastric mucosa of patients with gastric symptoms and who present with gastritis at histology. The aim of this study was to investigate the association between the presence of H. heilmannii type 1 and lesions of the pars esophagea. METHODS: H. heilmannii type 1 infection was investigated by mouse inoculation, urease test, and carbolfuchsin stain in 20 stomachs with ulcer, 30 stomachs with preulcer lesions, and 20 stomachs with a macroscopically normal pars esophagea. RESULTS: The microorganism was more frequently found in the stomachs with ulcer (100%) and in those with preulcer lesions (90%) than in stomachs with macroscopically normal pars esophagea (35%). Histological alterations were observed in the pars esophagea and in the glandular regions of bacterium-positive stomachs. CONCLUSIONS: It has been shown that the microorganism is strongly associated with naturally occurring ulcer and preulcer lesions of the pars esophagea of swine, which raises the possibility that the bacterium is an important factor in the pathogenesis of these lesions.

Animals↗

PubMed1996

Helicobacter trogontum sp. nov., isolated from the rat intestine.

A new Helicobacter species that colonizes the colonic mucosa of Wistar and Holtzman rats was isolated and characterized. This bacterium was gram negative, its cells were rod shaped with pointed ends, and its protoplasmic cylinder was entwined with periplasmic fibers. It was catalase and oxidase positive, rapidly hydrolyzed urea, and was susceptible to metronidazole and resistant to cephalothin and nalidixic acid. The new organism was microaerophilic and grew at 42 degrees C, a feature that differentiates it from two other murine intestine colonizers, Helicobacter hepaticus and Helicobacter muridarum. On the basis of 16S rRNA sequence analysis data, the new organism was identified as a Helicobacter species that is most closely related to H. hepaticus. This bacterium is named Helicobacter trogontum. The type strain is strain LRB 8581 (= ATCC 700114).

Animals↗

PubMed1996

Experimental infection of Wistar rats with 'Gastrospirillum suis'.

In order to develop a model for the study of gastric spiral bacteria, and based on the observation that Wistar rats do not carry urease-positive spiral bacteria in their gastric mucosa, mucus from a pig naturally colonised by 'Gastrospirillum suis' (an organism with I6S rDNA 99.5% similar to that of 'G. hominis' type 1), was inoculated into 35 Wistar rats (test group). Fourteen rats were given mucus taken from 'G. suis'-negative swine (control group). Five test animals and two controls were killed 1, 2, 4, 8, 12, 26, and 52 weeks after inoculation. 'G. suis' was observed in the antral mucosa of all test rats but not in the gastric mucosa of any control animal. The number of organisms was high from the beginning of the infection and increased over the period of observation. The bacteria were seen deep in the gastric antral glands, especially in the advanced stages of infection. Histological study of two test rats killed 1 week after inoculation and of all rats killed from the second week after infection revealed the presence of a mild inflammatory response characterised by the infiltration of small numbers of mononuclear cells and scarce polymorphonuclear cells in the subglandular region of the antral mucosa. Lymphoid aggregates were observed in the antral mucosa of rats killed from 1 month onwards, and increased in size and number over the period of infection. Control animals did not have any histological changes in the gastric mucosa. The natural transmission of the bacterium from rat to rat was also investigated. Five non-inoculated animals (contact group) and rats of the test group were maintained in the same cage and killed after 12 weeks. Two animals of the contact group showed slight infiltration of mononuclear cells in the antral mucosa, although they were not colonised by 'G. suis', a finding that supports the hypothesis of faecal-oral transmission of gastric Helicobacter spp. This animal model could be used not only to understand different aspects of the relationship between spiral bacteria and the gastric mucosa but also to obtain large numbers of the organism, free from other spiral bacteria to study some of its properties.

Animals↗

PubMed1995

Helicobacter bilis sp. nov., a novel Helicobacter species isolated from bile, livers, and intestines of aged, inbred mice.

A fusiform bacterium with 3 to 14 multiple bipolar sheathed flagella and periplasmic fibers wrapped around the cell was isolated from the liver, bile, and lower intestine of aged, inbred mice. The bacteria grew at 37 and 42 degrees C under microaerophilic conditions, rapidly hydrolyzed urea, were catalase and oxidase positive, reduced nitrate to nitrite, did not hydrolyze indoxyl acetate or hippurate, and were resistant to both cephalothin and nalidixic acid but sensitive to metronidazole. On the basis of 16S rRNA gene sequence analysis, the organism was classified as a novel helicobacter, Helicobacter bilis. This new helicobacter, like Helicobacter hepaticus, colonizes the bile, liver, and intestine of mice. Although the organism is associated with multifocal chronic hepatitis, further studies are required to ascertain whether H. bilis is responsible for causing chronic hepatitis and/or hepatocellular tumors in mice.

Aging↗