Obirajara Rodrigues

Evaluation of diagnostic methods for the detection of Helicobacter pylori in gastric biopsy specimens of dyspeptic patients

Helicobacter pylori infects nearly 50% of the world’s population. This microorganism is accepted as the most important agent of gastritis and as a risk factor for peptic ulcer disease and gastric adenocarcinoma. Currently many diagnostic methods exist for detecting H. pylori, however they all have limitations, thus it is recommend a combination of at least two methods. The aim of this study was to evaluate diagnostic methods, such as in-house urease test, culture and Polymerase Chain Reaction (PCR), for the detection of the H. pylori in gastric biopsy specimens of 144 dyspeptic patients, using as gold standard the association between histology and rapid urease test. According to the gold standard used in this study, 48 (33.3%) patients were infected with H. pylori, while 96 (66.7%) were classified as not infected. The in-house urease test and the PCR were the most sensitive methods (100%), followed by culture (85.4%). However, the inhouse urease test and the culture were the most specific (100%), followed by PCR (75%). In conclusion, this study showed that, in comparison with the combination of histology and rapid urease test, the in-house urease test and the PCR presented 100% of sensitivity in the diagnosis of gastric infection by H. pylori, while the in-house urease test and the culture reached 100% of specificity. These finding suggest that the combination of two or more methods may improve the accuracy of the H. pylori detection.

Molecular Basis of Pathogenicity in Helicobacter pylori Clinical Isolates

ABSTRACT This study identified pathogenicity genes in 40 Helicobacter pylori clinical isolates. The cagA, vacA, and iceA genes were detected in 65%, 97.5%, and 97.5% of the isolates, respectively. The cagA, iceA1, and vacAs1a/m1 genes were related to erosive gastritis, whereas the vacAs2/m2 and iceA2 genes were associated with enanthematous gastritis.

Skin irritation and histopathologic alterations in rats exposed to lightstick contents, UV radiation and seawater.

Lightsticks are fishing gadgets that provide fluorescent lighting when two organic solutions are mixed. In NE Brazil, low-income coastal residents ignore their conventional use and collect lightsticks stranded on beaches. The lightstick solution is then used for various purposes, including direct human skin exposure. We assessed the reactions and possible cell damages on the skin of Wistar rats. Animals were exposed to lightstick contents, UV radiation and/or seawater. Lightstick exposure led to erythemas, oedemas and vesicles. Histopathologic alterations included proliferation of the epidermis and inflammatory infiltrates. In spite of the short time of experimentation (4 days), the rats exposed to the lightstick content alone and together with UV radiation and/or seawater provided evidence of irritation/alteration reactions that may evolve into skin cancer. Our results demonstrated a few of the potential problems associated with lightstick dumping into the ocean and highlight the need for further investigations about this new type of marine pollutant.

SENSIBILIDADE E ESPECIFICIDADE DAS ALTERAÇÕES HISTOPATOLÓGICAS DE MUCOSA GÁSTRICA ANTRAL PARA O DIAGNÓSTICO DA INFECÇÃO PELO Helicobacter pylori

O Helicobacter pylori e considerado o patogeno mais prevalente no mundo e e a causa mais frequente de gastrite cronica ativa. A sensibilidade e especificidade de alteracoes histologicas da gastrite cronica no curso da infeccao pelo H. pylori sao investigados neste trabalho. Estudo retrospectivo de 241 diagnosticos, a partir de biopsia de mucosa gastrica antral, foi realizado no Laboratorio de Anatomia Patologica do Hospital Universitario da Fundacao Universidade Federal do Rio Grande, usando a tecnica de coloracao de Hematoxilina & Eosina e Giemsa, com o objetivo de avaliar o grau de gastrite e a presenca de alteracoes morfologicas do epitelio gastrico, associadas a presenca do H. pylori. Foram avaliadas a sensibilidade e especificidade para o H. pylori das seguintes alteracoes histologicas: infiltracao de neutrofilos no corio e epitelio, presenca de foliculo linfoide, hiperplasia dos colos glandulares e foveolas, abscesso de cripta, metaplasia intestinal e injuria epitelial. Quanto ao grau de gastrite, foram observados 63 casos de gastrite leve, sendo 33 (52,4%) casos de H. pylori positivo; 122 casos de gastrite moderada, sendo 114 (93%) casos de H. pylori positivo; 43 casos de gastrite acentuada, sendo 38 (88,4%) casos H. pylori positivo. A infiltracao de neutrofilos no corio e no epitelio foram as alteracoes que apresentaram maior sensibilidade para o H. pylori, com 98,4 e 86,6%. A especificidade dessas alteracoes foi de 40,7 e 42,6%, respectivamente. Estes resultados indicam que a infiltracao de neutrofilos no corio ou epitelio da mucosa gastrica antral e de alta sensibilidade para indicar a presenca do H. pylori.