Amanda Alves Fecury

Bio: Amanda Alves Fecury is an academic researcher from Federal University of Pará. The author has contributed to research in topics: Humanities & Medicine. The author has an hindex of 9, co-authored 82 publications receiving 274 citations.

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

Abstract: 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.

ABH and Lewis antigen distributions in blood, saliva and gastric mucosa and H pylori infection in gastric ulcer patients

Abstract: AIM: To investigate the ABH and Lewis antigen expression in erythrocytes, saliva and gastric epithelium, as well as the association between H pylori and the presence of gastric epithelial lesions. METHODS: The distribution of ABH and Lewis blood group antigens in erythrocytes, saliva and gastric mucosa of H pylori-infected gastric ulcer patients was analyzed. Forty-two patients with gastric ulcer were studied, and fifty healthy individuals were used as control group. The blood group antigens were determined by direct hemagglutination, dot-ELISA and immunohistochemical methods in erythrocytes, saliva and gastric mucosa specimens, respectively. Diagnosis for H pylori infection was performed by conventional optical microscopy and ELISA. RESULTS: A higher seroprevalence of IgG H pylori specific antibodies was observed in gastric ulcer patients (90%) compared to the control group (60%). We observed a significant increase of phenotypes O, A2 and Lewis b in H pylori-infected patients. The expression of these antigens had progressive alterations in areas of ulcerous lesions and intestinal metaplasia. CONCLUSION: ABH and Lewis blood group antigens are a good indicator for cellular alterations in the gastric epithelium.

Hepatitis B and C virus infection among Brazilian Amazon riparians

Abstract: 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 Pacui Island, within the Cameta municipality of Para 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.

Helicobacter pylori infection and immune profile of patients with different gastroduodenal diseases.

Abstract: A associacao da infeccao por Helicobacter pylori com diferentes doencas gastroduodenais pode estar associada a fatores bacterianos, do hospedeiro e do ambiente. Nesse contexto, estudos tem demonstrado que a diversidade genetica do H. pylori, sobretudo nos genes vacA e cagA, esta associada ao desenvolvimento de doencas gastroduodenais como a ulcera peptica e o câncer gastrico. Alem disso, a natureza da resposta inflamatoria do hospedeiro pode explicar essas diferentes manifestacoes da infeccao por esse microrganismo. Portanto, fatores do hospedeiro que regulam as respostas imunologica e inflamatoria, envolvendo a interacao funcional da infeccao por H. pylori com diferentes membros do compartimento imunologico, especialmente respostas imunes de celulas T nas doencas gastroduodenais, ainda precisam ser melhor estudados. Objetivo: Caracterizar a resposta imune, incluindo imunidade induzida por infeccao pelo H. pylori, especialmente com cepas virulentas de H. pylori (alelos vacA e gene cagA), atraves da analise do perfil de citocinas e da caracterizacao da populacao de celulas T presentes em doencas gastroduodenais em nossa populacao. Metodos: Em um estudo prospectivo, foram coletadas biopsias gastricas de 554 pacientes portadores das diferentes doencas gastroduodenais. Nas amostras biologicas destes pacientes foi realizada a determinacao do genotipo bacteriano e a deteccao das citocinas IL-4, IL-10, INF-γ e IL-12 atraves do metodo Elisa. Foram obtidas biopsias gastricas para avaliacao histologica. Resultados: Observamos que o genotipo predominante nas cepas de H. pylori isoladas dos pacientes estudados foi s1m1cagA positivo, sendo mais frequentes entre os pacientes com ulcera gastrica, ulcera duodenal e câncer gastrico. Houve associacao significativa das cepas com o genotipo s1m1cagA positivo com maior grau de inflamacao, atividade neutrofilica e desenvolvimento de metaplasia intestinal. As concentracoes gastricas de INF-γ e IL-12 foram significativamente mais elevadas em pacientes infectados pelo H. pylori do que nos nao infectados. Foram detectados niveis mais elevados dessas citocinas nos portadores de ulcera e câncer gastrico, sendo que nesses pacientes foram observados niveis mais baixos de IL-4 e IL-10 na mucosa gastrica. Alem disso, as concentracoes de INF-γ e IL-12 em biopsias gastricas, foram mais elevadas nos pacientes portadores das cepas bacterianas virulentas s1m1cagA+. Contrariamente, os niveis de IL-4 e IL-10 foram maiores em tecido infectado por cepas s2m2cagA. Pacientes com maior grau de inflamacao, de atividade neutrofilica e presenca de metaplasia intestinal, apresentaram niveis mais elevados de INF-γ e IL-12 e uma concentracao mais baixa de IL-4 e IL-10 nas biopsias gastricas. Conclusao: Nosso estudo demonstra que a interacao entre o tipo de cepa infectante e resposta imunologica com perfil Th1, podem influenciar e perpetuar a inflamacao gastrica contribuindo para o desenvolvimento de diferentes manifestacoes clinicas na infeccao pelo H. pylori.

Prevalence of hepatitis C virus infection and genotypes in patient with chronic kidney disease undergoing hemodialysis.

Abstract: The prevalence of antibodies to HCV varies among Brazilian regions at rates of 8-16%. Since this virus is transmitted by the parenteral route through blood and blood products, patients receiving maintenance hemodialysis therapy are at an increased risk of infection. The study was conducted in seven dialysis centers in Belem, Para, northern Brazil. Blood samples were collected from 798 patients with chronic renal disease treated by hemodialysis. The samples were tested for antibodies against HCV and the viral genotype was identified. Sixty-seven (8.4%) of the 798 patients studied were anti-HCV positive by ELISA, ranging from 4% to 14% in different centers. Viral RNA was detected in 5.3% (43/798) of the patients; of these, 42 also had anti-HCV antibodies. HCV genotyping revealed genotype 1 as the most common, detected in 86.1% (37/43) of the patients, followed by genotype 2 in 11.6% (5/43) and genotype 3 in one patient (2.3%). The findings of this study highlight the importance of control strategies for hepatitis C in hemodialysis patients. Molecular biology methods need to be available in these centers to screen for HCV on admission in order to establish effective infection control measures.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Blood Groups in Infection and Host Susceptibility

Abstract: SUMMARY Blood group antigens represent polymorphic traits inherited among individuals and populations. At present, there are 34 recognized human blood groups and hundreds of individual blood group antigens and alleles. Differences in blood group antigen expression can increase or decrease host susceptibility to many infections. Blood groups can play a direct role in infection by serving as receptors and/or coreceptors for microorganisms, parasites, and viruses. In addition, many blood group antigens facilitate intracellular uptake, signal transduction, or adhesion through the organization of membrane microdomains. Several blood groups can modify the innate immune response to infection. Several distinct phenotypes associated with increased host resistance to malaria are overrepresented in populations living in areas where malaria is endemic, as a result of evolutionary pressures. Microorganisms can also stimulate antibodies against blood group antigens, including ABO, T, and Kell. Finally, there is a symbiotic relationship between blood group expression and maturation of the gastrointestinal microbiome.

Helicobacter pylori Virulence Factors-Mechanisms of Bacterial Pathogenicity in the Gastric Microenvironment.

Abstract: Gastric cancer constitutes one of the most prevalent malignancies in both sexes; it is currently the fourth major cause of cancer-related deaths worldwide. The pathogenesis of gastric cancer is associated with the interaction between genetic and environmental factors, among which infection by Helicobacter pylori (H. pylori) is of major importance. The invasion, survival, colonization, and stimulation of further inflammation within the gastric mucosa are possible due to several evasive mechanisms induced by the virulence factors that are expressed by the bacterium. The knowledge concerning the mechanisms of H. pylori pathogenicity is crucial to ameliorate eradication strategies preventing the possible induction of carcinogenesis. This review highlights the current state of knowledge and the most recent findings regarding H. pylori virulence factors and their relationship with gastric premalignant lesions and further carcinogenesis.