جستجوی مقالات مرتبط با کلیدواژه « caga » در نشریات گروه « پزشکی »

Helicobacter pylori infections vary in severity and virulence in different populations for various reasons. There are different H. pylori strains with varying degrees of virulence. The genetic diversity of H. pylori strains in gastritis patients in different areas has not been well understood. This study aimed to evaluate the prevalence rate and different genotypes of H. pylori strains in clinical specimens of patients with gastritis in Ilam, Iran.

Saliva and gastric biopsy samples were collected from 81 patients (55 males and 26 females in the age range of 20 to 90 years) referring to Ilam medical centers. After DNA extraction, the prevalence of H. pylori as well as vacA, cagA, and ureC genes was evaluated using PCR, and then each vacA-positive sample was further evaluated for m1m2 and s1s2 variants.

The cagA and vacA genes were found in 27 (71%) and 36 (94.7%) H. pylori-positive samples, respectively. The cagA gene was detected in patients with gastric pain (44.4%) and anorexia (18.51%). Also, the results showed that the vacA s2m2 genotype and m2 allele were present in 32.9% of H. pylori isolates. Moreover, s2m2 and s1m2 genotypes were detected in 42.1 and 26.3% of vacA-positive samples, respectively. The lowest frequency was related to the m1 allele (17.18%).

This study results indicate a plausible relationship between the presence of some genotypes of H. pylori and the progression of gastritis, suggesting these markers as promising biomarkers to predict the disease severity.

This study aimed to determine the current EPIYA motifs of the cagA gene in Helicobacter pylori isolates from patients with gastric disorders, and evaluate the association between these patterns and the clinical outcome of H. pylori infection in different geographical regions of Iran.

We examined 150 patients with gastrointestinal disorders from the central and eastern regions of Iran. The detection of H. pylori and screening of cagA was performed by polymerase chain reaction (PCR). The pattern of the motifs was determined by PCR followed by sequencing.

The overall prevalence of H. pylori was 66.3% in eastern (Mashad) and 50.6% in the central (Isfahan) part of Iran. The frequency of cagA‑positive strains in Mashad and Isfahan were 63.4% and 56.7%, respectively. The pattern of EPIYA motif was as follows: 43 (79.6%) ABC, 7 (12.9%) AB, 4 (7.4%) ABCC, and one (1.9%) ABCCC. We also identified a novel EPIYA C sequence motif which showed association with gastric cancer (GC). The relationship between the frequency of specific EPIYA motifs and GC was statistically significant (P < 0.05).

This is the first report for the determination of the cagA EPIYA motif of H. pylori in the Northeast and center of Iran. The prevalence of cagA positive H. pylori between the two regions was significant (P ≤ 0.05). All isolates of the H. pylori cagA were western type (ABC). The increase in the number of EPIYA‑C repeats was associated with GC (P ≤ 0.01).

Helicobacter pylori infection can be a risk factor for non-cardia gastric cancer. In the present study, we aimed to assess the rate of Helicobacter pylori infection, its virulence factor and precancerous lesion among over 50 years old, dyspeptic patients with normal endoscopy.

A total of 620 patients over 50 years of age with dyspepsia that referred to Shahid Sadoughi Hospital, Yazd, Iran from December 2018 to January 2019 were evaluated. One hundred fifty patients with normal appearance endoscopy were selected, and six gastric biopsy specimens were taken from each subject. Data were analyzed using chi-square and logistic regression tests.

A total of 150 patients with mean age of 65.8±11.9 years old participated in this study. Sixty-three (42%) patients were males. Thirty-four (22.6%) patients had precancerous lesions. Ninety (60%) patients had positive PCR results for H. pylori. H. pylori infection test was positive in 24 (70.6%) patients with precancerous lesion. Sixty-six (57%) patients without the precancerous lesions (116 cases) were positive for H. pylori.

There was no a significant difference in the rate of H. pylori infection and its genotype distribution was between patients with and without the precancerous lesions.

Iran has a high incidence rate for gastric cancer among the Middle East countries. In addition to gastric cancer, peptic ulcer is also life-threatening; thus, investigating the prevalence of Helicobacter pylori infection and other risk factors are essential. The present study was aimed to assess the frequency of H. pylori and the cagA-positive strains in patients with gastric cancer or peptic ulcer at a teaching hospital in Qom, one of the most populated cities of Iran.

The presence of H. pylori was investigated in gastric cancer and peptic ulcer biopsy specimens using the standard culture method. PCR analysis was performed to detect the presence of the cagA gene.

The frequency of H. pylori isolates among 86 investigated biopsies was 20 (23.2%). Likewise, the rate of H. pylori was the highest when samples were examined from patients with gastric cancer (25.8%), while it was 21.8% when obtained from peptic ulcer patients. The frequency of the cagA gene in H. pylori isolates was 9 (56.2%), as confirmed by PCR.

Our results indicated that H. Pylori infection and its virulent strains are frequent and widely spread in Qom city. The cagA gene was present in almost half of H. pylori isolates from peptic ulcer or gastric cancer patients. Therefore, it is necessary to screen it in all cases with H. pylori infection for early detection of gastric cancer.

Cytotoxin associated gene A (CagA) and vacuolating cytotoxin A (VacA) proteins are the main Helicobacter pylori virulence factors. These toxins are associated with severe gastric diseases. Flavonoids are plant secondary metabolites that have shown great antibacterial effects. This work aimed to study the interaction of a set of flavonoid compounds with CagA and VacA proteins using molecular docking.

A set of 54 flavonoid compounds were used in this study, and 36 of which passed the Lipinski rules of 5. The 3D structures of CagA and VacA proteins were obtained from the Protein Data Bank. The molecular docking was performed using AutoDock Vina software and the results were expressed in terms of binding energies (kcal/mol). Protein-ligand interactions were analyzed using PyMOL software.

For the CagA protein, the licochalcone A molecule showed the highest binding affinity (-8 kcal/mol). For the VacA protein, the galangin, luteolin, and apigenin molecules showed the highest binding affinity (-8.9, -8.5, and -8.2 kcal/mol, respectively). Interactions of the licochalcone A, galangin, luteolin, and apigenin with CagA and VacA proteins involved their hydroxyl groups and/or their carbonyl groups.

Our study showed that these compounds might have the potential for their development into drugs for controlling H. pylori pathogenicity.

This study aimed to assess construction and expression of CagA recombinant protein of Helicobacter pylori (H. pylori) in Escherichia coli (E. coli) BL21.

Bioinformatics was used in designing the desired gene by Gene Runner. Next, the construct was subcloned to pET21b vector and this process was confirmed by Polymerase Chain Reaction (PCR), enzyme digestion and sequencing techniques. Then, it was cloned in the Escherichia coli BL21 as an expression host. Expression of protein was verified using sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting technique. For purification of the protein, the Ni-NTA column was used. Protein concentration was determined by the Bicinchoninic Acid Protein Assay Kit (Parstoos). Finally, Western blotting was performed using CagA antibodies and normal human serum for determining immunogenicity feature with human antiserum.

According to the results of the present study, CagA construct was cloned into the pET21b vector and after confirmation and cloning in host expression, recombinant protein with the size of 38 kDa was successfully expressed and purified. The recombinant CagA protein showed immunogenicity characteristics with human antiserum.

In conclusion, only 5′-end of recombinant protein CagA with high immunogenicity effects was successfully constructed, cloned and expressed. Also, CagA recombinant protein showed good immunogenicity activity with human antiserum.

Brucellosis is one of the current zoonotic diseases, still a health hazard in many countries, and progressive research programs are necessary to control and eradicate this disease in endemic areas. Outer membrane proteins (OMPs) are capable of allocating immunity and protection antigen in mice. CagA is an immunogenic protein of Helicobacter pylori. Because OMPs are part of Brucella </em>spp, they have been conferred as potential immunogenic and protective antigens. In this study, the gene sequence which encoding TN-OMPs was obtained from GenBank. To estimate the 3D structure of the protein, modeling, prediction of secondary and tertiary structure, immunogenicity, allergenic sites and antigenic B-cell and T-cell epitopes were performed. The conserved domain of proteins was obtained and the epitopes of TN-OMPs were capable of inducing both B-cell and T-cell mediated immune responses. CagA is a cellular immunogenic protein that induces a Th1 response. The OMPs of Brucella could be used as a suitable vaccine candidate versus brucellosis.

Helicobacter pylori, a worldwide infection, is associated with several infectious diseases including gastric ulcer, peptic ulcer, and gastric cancer resulting from the cytotoxinassociated gene A (CagA). The purpose of this study was to evaluate the seroprevalence of anti-H. pylori and anti-CagA IgG antibodies in Iranian dyspeptic patients. In this prospective epidemiological survey, a total of 659 patients were evaluated for the presence of general anti-H. pylori IgG, and then for anti-CagA IgG by two commercial ELISA kits. The prevalence of general anti-H. pylori IgG was 58.1% (383 of 659 patients) which increased progressively with age (P<0.05) and was not significantly influenced by the sex (P=0.08). The prevalence of anti-CagA IgG antibody in seropositive and seronegative patients for general H. pylori IgG was 52.9% (37 of 70) and 61.9% (13 of 21), respectively. This is the first report on the high prevalence of anti-CagA IgG in both seropositive and seronegative patients for general IgG, indicating the importance of this antibody in diagnosis of H. pylori positive patients after seroconversion of the general IgG.

The cytotoxin-associated gene (cag) pathogenicity island is reported to be a major virulence factor of Helicobacter pylori infection. It is previously reported that the cagA-positive strains are more virulent, so it can be postulated that the cagA-positive gastritis will be more severe and the serum immunoglobulin G (IgG) and A (IgA) anti-CagA antibody titer will be higher. The aim of this study was to compare the relationship between IgG and IgA anti-CagA antibody and the cagA gene expression in patients with dyspepsia. Serum samples obtained from 130 dyspeptic patients with positive H. pylori in histological and Geimsa staining were tested for serum IgG and IgA anti-CagA antibody using the enzyme-linked immunosorbent Assay. The expression of the cagA gene was determined using PCR on the biopsy samples, taken via endoscopy.
In our material, the sensitivity of IgG anti-CagA antibody in identifying patients with a proven infection with the cagA-positive strains was 97.67%, and the negative likelihood ratios was 0.06. There was not significant correlation between serum IgA anti-CagA and the expression of the cagA gene among the dyspeptic patients.
The IgG antibody titer was significantly higher in our patients with the cagA-positive H. pylori strain. However, in daily practice, the level of the IgG antibody titer cannot predict whether or not an individual carries a cagA-positive H. pylori strain, because there is a major overlap in the IgG antibody titer between the cagA-positive and cagA-negative patients.

There should be a public environmental reservoir for Helicobacter pylori in the developing countries, such as Iran, due to their high infection rate of over 70%. Epidemiological findings revealed that water could be a possible source of H. pylori transmission. However, high prevalence of H. pylori in drinking water in Kermanshah, West of Iran, was detected in the authors’ previously published study. The current study aims at designing a more accurate and rapid procedure to investigate the prevalence of Helicobacter species and cagA gene in drinking water samples in Kermanshah, from October to December 2012.
In the current study, 60 tap water samples were obtained and specific polymerase chain reaction (PCR) targeted cagA and 16s rRNA was performed. A loop-mediated isothermal amplification (LAMP) targeted ureC gene was developed to accurately detect H. pylori in water samples.
The prevalence of ureC by PCR, ureC by LAMP and 16s rRNA by PCR were 26.67%, 38%, and 61.67%, respectively. Among 24 samples (40%), 1 of the 2 tests was positive. The prevalence of cagA gene among ureC positive, 16s rRNA positive and all samples were 18.75%, 13.51%, and 10%, respectively.
Helicobacter pylori contamination in drinking water was considerably higher using LAMP compared with PCR. It is noteworthy that some H. pylori positive samples were also positive for Caga.