Tereza Cristina de Oliveira Corvelo

Clinical and pathological importance of vacA allele heterogeneity and cagA status in peptic ulcer disease in patients from North Brazil.

We have examined the prevalence of gene cagA and vacA alleles in 129 patients, 69 with gastritis and 60 with peptic ulcer diseases from North Brazil and their relation with histopathological data. vacA and cagA genotype were determined by polymerase chain reaction. Hematoxylin-eosin staining was used for histological diagnosis. 96.6% of the patients were colonized by Helicobacter pylori strains harboring single vacA genotype (nont-mixed infection). Among them, 11.8% had subtype s1a, 67.8% had subtype s1b, and 17% subtype s2. In regard to the middle region analysis, m1 alleles were found in 75.4% and m2 in 21.2% of patients. The cagA gene was detected in 78% patients infected with H. pylori and was associated with the s1-m1 vacA genotype. The H. pylori strains, vacA s1b m1/cagA-positive, were associated with increased risk of peptic ulcer disease and higher amounts of lymphocytic and neutrophilic infiltrates and the presence of intestinal metaplasia. These findings show that cagA and vacA genotyping may have clinical relevance in Brazil.

Determination of strains of Helicobacter pylori and of polymorphism in the interleukin-8 gene in patients with stomach cancer.

CONTEXT Gastric neoplasia is the second most common cause of death by cancer in the world and H. pylori is classified as a type I human carcinogen by the World Health Organization. However, despite the high prevalence of infection by H. pylori around the world, less than 3% of individuals carrying the bacteria develop gastric neoplasias. Such a fact indicates that evolution towards malignancy may be associated with bacterial factors in the host and the environment. OBJECTIVES To investigate the association between polymorphism in the region promoting the IL-8 (-251) gene and the H. pylori genotype, based on the vacA alleles and the presence of the cagA gene, using clinical and histopathological data. METHODS In a prospective study, a total of 102 patients with stomach cancer and 103 healthy volunteers were analysed. Polymorphism in interleukin 8 (-251) was determined by the PCR-restriction fragment length polymorphism reaction and sequencing. PCR was used for genotyping the vacA alleles and the cagA in the bacterial strains PCR. Gastric biopsies were histologically assessed. RESULTS The H. pylori serology was positive for 101 (99%) of all patients analysed, and 98 (97%) of them were colonized by only one strain. In patients with monoinfection, 82 (84%) of the bacterial strains observed had the s1b/m1 genotype. The cagA gene was detected in 74 (73%) of patients infected by H. pylori. The presence of the cagA gene was demonstrated as associated with the presence of the s1b/m1 genotype of the vacA gene (P = 0.002). As for polymorphism in the interleukin 8 (-251) gene we observed that the AA (P = 0.026) and AT (P = 0.005) genotypes were most frequent in the group of patients with gastric adenocarcinoma. By comparing the different types of isolated bacterial strains with the interleukin -8 (-251) and the histopathological data we observed that carriers of the A allele (AT and AA) infected by virulent strains (m1s1 cagA+) demonstrated a greater risk of presenting a degree of inflammation (OR = 24.75 CI 95% 2.29-267.20 P = 0.004) and increased neutrophilic activity (OR = 28.71 CI 95% 2.62-314 P = 0.002) in the gastric mucosa. CONCLUSION Our results demonstrate that the interaction between polymorphism in the interleukin -8 (-251) gene, particularly with carriers of the A allele and the infecting type of H. pylori strain (s1m1 cagA positive) performs an important function in development of gastric adenocarcinoma.

Hepatitis B and C virus infection among Brazilian Amazon riparians

INTRODUCTION Viral hepatitis is a major public health concern in Brazil. There are few past studies on this issue, especially among riparian communities. This study aims at determining the seroprevalence of viral hepatitis B and C in the riparian community of Pacuí Island, within the Cametá municipality of Pará State, Brazil. Moreover, this study aims to investigate the principal risk factors that this community is exposed to. METHODS The current study has accessed blood samples from 181 volunteers who have answered an epidemiological questionnaire. Analyses on serological markers have been tested with commercial ELISA kits for detecting HBsAg, total anti-HBc, anti-HBs, and anti-HCV. Within seroreactive patients for HCV, RT-PCR and line probe assay have been performed to identify the viral genotype. RESULTS In the serological marker analysis for hepatitis B, no reactivity for HBsAg, rate of 1.1% for total anti-HBc, and rate of 19.3% for anti-HBs have been observed. On hepatitis C, 8.8% seroprevalence has been found, in which 62.5% have gotten viral RNA. Among the risk factors studied, the following have been highlighted: non-use of condoms, sharing of cutting instruments, use of illicit drugs, and reports of family disease with HBV or HCV. CONCLUSIONS The vaccination coverage against HBV is low, and the high prevalence of HCV within this community has been observed.

Molecular identification of rapidly growing mycobacteria isolates from pulmonary specimens of patients in the State of Pará, Amazon region, Brazil.

We isolated 44 strains of rapidly growing mycobacteria (RGM) from 19 patients with pulmonary infections assisted at the Instituto Evandro Chagas (Pará, Brazil) from 2004 to 2007. Identification at the species level was performed by PCR restriction fragment length polymorphism analysis (PRA) of a 441 bp hsp65 fragment and partial 16S rRNA, hsp65, and rpoB gene sequencing. Genotyping by PRA yielded 3 digestion patterns: one identical to Mycobacterium abscessus type I (group I); another to M. abscessus type II, Mycobacterium bolletii, and Mycobacterium massiliense (group II); and a third typical for Mycobacterium fortuitum type I (group III). When comparing analysis of the 3 genes, more discrimination was obtained by rpoB gene sequence, which allowed good distinction between group I, II, and III strains and subclassification of group II strains in SG IIa (M. bolletii) and SG IIb (M. massiliense). In this study, we show that the description of new RGM species requires the establishment of standardized procedures for RGM identification and the alert of the clinician about their involvement in pulmonary disease and the necessity of treatment for control and cure.

The expression of ABH and Lewis antigens in Brazilian semi-isolated Black communities

The expression of the ABH and Lewis blood groups was determined in blood and saliva samples from two semi-isolated Black communities of Northern Brazil: Cameta and Alcântara. The distributions of ABO blood group phenotypes and the ABH secretor status frequencies showed no significant differences between these populations. In contrast, there was a difference regarding the frequency of the red blood cell Le(a-b-) phenotypes, associated with erythrocyte/saliva discordance, as confirmed by the observation that individuals with Le(a-b-) red cells have the Lewis antigen in their saliva, resulting in a nongenuine Le(a-b-) phenotype, whose frequency was higher in Alcântara.

Helicobacter pylori in children and association with CagA strains in mother-child transmission in the Brazilian Amazon region

The prevalence of Helicobacter pylori infection was investigated in blood samples from 100 children aged 1 to 12 years and from their mothers, by means of the indirect hemagglutination and anti-CagA methods, using ELISA assays. From these 100 children, 79 stool samples were obtained and bacterial antigens in the stools were investigated using capture ELISA. The antigens were detected in 54.4% (43/79) of the children, and serum antibodies in 43% (34/79). These methods presented similar performance, with greatest disagreement among the children aged 1 to 4 years. The seroprevalence was 50% (50/100) among the children and 86% (86/100) among the mothers. Infected mothers represented a risk factor that was 19 times greater than that of seronegative mothers, with regard to infecting their children (p < 0.05), especially the mothers with CagA+ strains (p < 0.05). Direct person-to-person contact may be a transmission method for this infection.

Expressão dos antígenos ABH e Lewis na gastrite crônica e alterações pré- neoplásica da mucosa gástrica

RESUMO – Racional - A aderencia do Helicobacter pylori a mucosa gastrica humana e pre-requisito para sua colonizacao e o desenvolvimento da gastrite cronica. Os antigenos de grupos sanguineos, presentes no muco gastrico, sao descritos como provaveis receptores da bacteria neste epitelio. A expressao alterada destes antigenos esta associada ao desenvolvimento do câncer gastrico. Objetivos - Verificar a ocorrencia do Helicobacter pylori e a distribuicao da expressao dos antigenos ABH e Lewis correlacionada com as alteracoes histopatologicas de pacientes com gastrite cronica. Pacientes e Metodos – Analisaram-se 63 amostras de sangue, saliva e biopsias gastricas de pacientes com gastrite cronica atraves das tecnicas dot-blot-ELISA, imunoperoxidase indireta e coloracoes do Gram modificado e hematoxilina-eosina. Resultados - Nao foram encontradas associacoes significativas entre a presenca da bacteria e os fenotipos de grupos sanguineos ABH, Lewis e Secretor. Na maioria dos pacientes, a expressao dos antigenos ABH e Lewis, estava restrita principalmente ao epitelio foveolar da mucosa gastrica, concordando com a expressao ao nivel salivar. A expressao inapropriada desses antigenos ocorria sempre na infeccao pelo Helicobacter pylori e/ou alteracoes pre-neoplasicas da mucosa gastrica. Em areas com metaplasia intestinal foi observada a reducao da reatividade para os antigenos H e Leb, e principalmente o aumento de Lea. Conclusao - Alteracoes no padrao de glicosilacao destes antigenos refletem diferentes estagios de diferenciacao celular e sao marcadores potenciais na avaliacao diagnostica e prognostica das patologias gastricas. DESCRITORES – Helicobacter pylori. Infeccoes por helicobacter. Gastrite. Grupos sanguineos.

The Lewis Histo-Blood Group System: Molecular Analysis of the 59T>G, 508G>A, and 1067T>A Polymorphisms in an Amazonian Population

Background The Lewis (FUT3) gene is responsible for the expression of the Lea and Leb blood group antigens. The individuals, who not synthesize these antigens have the phenotype Lewis negative, due to the presence of some single nucleotide polymorphisms (SNPs), such as 59T>G, 508G>A and 1067T>A, whose distribution is different in various ethnic groups. Our aim was to verify the frequencies of these SNPs in an admixed population of Belém-Pará-Brazil. Materials and Methods Polymerase chain reaction/restriction enzyme method were used to detect these SNPs in the FUT3 gene, whereas Lewis phenotypes were defined by the direct hemagglutination and in saliva by Dot-Elisa assay in a random sample of 150 individuals from admixed population of Belém in the northeast Brazilian Amazon region. Results The frequency of these SNPs was detected as 47.6% (59T>G), 17.3% (508G>A) and 5.3% (1067T>A).The discrepancies between blood and salivary Lewis phenotypes are related to the relatively high frequencies of 59T>G and the null allele 508G>A. Whereas 38.6% of the individuals were Lewis negative based on blood, only 17.24% also tested negative when their saliva were analyzed. Conclusion We have found a marked consistency between the phenotypes and genotypes of the Lewis blood group system. Furthermore, our obtained FST values reveal distinct frequencies of the FUT3 SNPs between the present sample and its representative ancestral populations. These observations will help to evaluate the Lewis antigens impact as susceptibility markers, in genetic association studies to certain diseases.

Soroprevalência de anticorpos contra o antígeno CagA do Helicobacter pylori em pacientes com úlcera gástrica na região Norte do Brasil

O Helicobacter pylori e um agente patogenico largamente distribuido no mundo, estando envolvido no desenvolvimento de varias doencas gastrointestinais. Atualmente a infeccao pela cepa virulenta (CagA+) do H. pylori e considerado um dos principais fatores etiologicos para o desenvolvimento de ulceracoes gastricas. Baseado nessa informacao, investigamos a soroprevalencia das cepas virulentas entre os pacientes com ulcera gastrica da nossa regiao, utilizando testes sorologicos para deteccao de anticorpos contra o H. pylori e a proteina CagA. Sendo observado que 82% (45/55) dos pacientes estavam infectados pela cepa virulenta, entre esses 89% (40/45) apresentaram grau de inflamacao aumentado na mucosa gastrica, com denso infiltrado de leucocitos no tecido, o que provavelmente favoreceu a formacao das ulceracoes gastricas.Helicobacter pylori is a pathogenic agent with a worldwide distribution and is involved in the development of many gastrointestinal diseases. Nowadays infection with the virulent strain CagA+ of H. pylori is considered one of the main etiological factors in the development of gastric ulcer. Based on this information, we investigated the seroprevalence of virulent strains among patients with gastric ulcer from one region, using serologic tests to detect antibodies against H. pylori and CagA protein. Infection by the virulent strain was found in 82% (40/55) of the patients, and among these, 89% (40/45) presented an increased degree of inflammation in the gastric mucosa, with a dense infiltration of leukocytes in the tissue, which probably favored the formation of gastric ulcer. We concluded that the presence of the virulent strain is related to the development of an increased inflammation in the gastric mucosa.

Risk factors and pregnancy outcomes in women with syphilis diagnosed using a molecular approach

Objectives To investigate the risk factors for infection and the outcome of pregnancy in women diagnosed with syphilis using a molecular approach. Methods Case-control study of pregnant women admitted to a maternity ward, with the cases classified as early or latent maternal syphilis, based on clinical-serological diagnoses. The DNA of total peripheral blood was used to detect the polA gene using nested PCR (nPCR). The case and control groups were divided into subgroups based on whether the birth was successful (infant survived) or had a lethal outcome (miscarriage, stillbirth or neonatal death). Results The frequency of maternal syphilis was 1% (237/25 600), considering both those that had live births (71.3%, 169/237) and those with a lethal outcome (28.7%, 68/237), with a higher detection rate being provided by the nPCR in women with early syphilis. The cases of nPCR(+) congenital syphilis were more frequent in the women with early syphilis, nPCR(+) mothers and those who did not have treatment during the prenatal. The risk of maternal syphilis was greater in women who had not received preventive counselling, initiated sexual activity at 16 years of age or younger, had multiple partners, used drugs, were from households with a low income and poor sanitation, and had a history of miscarriage. Conclusions The risk factors for congenital syphilis are closely related to the health of the mother, reflecting the lack of adequate prenatal care. The high frequency of maternal syphilis was associated in particular to the socio-economic conditions of the mother and her sexual and reproductive health.