Análise epidemiológica e emprego do teste rápido da urease em pacientes com úlcera péptica perfurada

OBJETIVO: Analisar o perfil epidemiológico de pacientes com úlcera péptica gastroduodenal perfurada e verificar se a presença do H. pylori nas secreções peritoneais e intraluminais desses pacientes pode ser avaliada pelo teste rápido da urease. MÉTODOS: Realizou-se estudo prospectivo, transversal, descritivo, com dados de pacientes atendidos em um hospital de abrangência regional, em portadores de úlcera péptica perfurada. Coletou-se, no transoperatório, amostras de líquido peritoneal (na proximidade da perfuração) e da secreção intraluminal, sendo encaminhadas para cultura e teste rápido de urease. RESULTADOS: Quatorze pacientes foram analisados. A média etária foi 41,06 anos, todos homens, brancos (71,4%), tabagistas (57,2%), IMC < 30 (85,7%), com história prévia de dispepsia (78,6%). Sorologia para H. pylori foi positiva em 84,6% dos casos. O teste rápido da urease foi positivo em 78,6% das amostras do tubo digestivo e em 42,8% das amostras da cavidade peritoneal; 41,6% foram positivos em ambos os locais, 50% somente na cavidade digestiva e 8,4% exclusivamente na cavidade peritoneal. Dos 11 pacientes com sorologia positiva para H. pylori 100% apresentaram positividade em pelo menos um dos sítios pesquisados. CONCLUSÃO: Verificou-se que a incidência foi menor que a esperada. Há associação significativa entre a infecção pelo H. pylori e a ocorrência de perfuração. A presença deste patógeno pode ser avaliada tanto pela sorologia quanto pela realização do teste rápido da urease do fluido coletado na cavidade peritoneal e na luz gástrica/duodenal.

Gastric ulcers in pigs affected with postweaning multisystemic wasting syndrome

Samples of gastric lymph nodes and the stomachs from 24 pigs selected from herds affected by postweaning multisystemic wasting syndrome (PMWS) and sudden death associated with gastric ulcers were studied. Pigs were selected on the basis of unthriftiness, decreased feed intake, and wasting. The stomachs were opened, inverted, and classified into 0-3 score according the severity of the gross lesions present in pars oesophagica (non-glandulargastric mucosa). Selected samples were processed for paraffin embedding and stained with hematoxylin and eosin. Immunohistochemistry using anti-PCV2 (porcine circovírus type 2) antibody, anti-Helicobacter pylori antibody and a wide-spectrum anti-cytokeratin antibody was performed. Gross changes in pars oesophagea were classified according to the severity of lesions as score 3, 2, and 1 in 8, 6, 5 stomachs respectivelly. Microscopically, hyperplastic lymphoid follicles, lymphohistiocytic inflammatory infiltrates and focci of necrosis in the gastric mucosa were common findings. Large amounts of PCV2 antigen were observed in the cytoplasm and nuclei from intralesional cells and debris from the gastric glandular mucosal zone; however, in the fundus, anti-PCV2 immunostaining was restricted to the surface mucosal cells and foveolar compartment. All gastric lymph nodes were positive for PCV2 antigen. Anti-H. pylori immunostaining was seen in eleven cases, mainly in the antrum, on the mucosal surface and foveolar compartment. The association of the anti-PCV2 immunostaining with the glandular mucus-producing cells suggests a role for PCV2 as an additional factor for the swine ulcer development.

Application of isotope-selective non-dispersive infrared spectrometry for the evaluation of the 13C-urea breath test: comparison with three concordant methods

The aim of this work was to compare the performance of isotope-selective non-dispersive infrared spectrometry (IRIS) for the 13C-urea breath test with the combination of the 14C-urea breath test (14C-UBT), urease test and histologic examination for the diagnosis of H. pylori (HP) infection. Fifty-three duodenal ulcer patients were studied. All patients were submitted to gastroscopy to detect HP by the urease test, histologic examination and 14C-UBT. To be included in the study the results of the 3 tests had to be concordant. Within one month after admission to the study the patients were submitted to IRIS with breath samples collected before and 30 min after the ingestion of 75 mg 13C-urea dissolved in 200 ml of orange juice. The samples were mailed and analyzed 11.5 (4-21) days after collection. Data were analyzed statistically by the chi-square and Mann-Whitney test and by the Spearman correlation coefficient. Twenty-six patients were HP positive and 27 negative. There was 100% agreement between the IRIS results and the HP status determined by the other three methods. Using a cutoff value of delta-over-baseline (DOB) above 4.0 the IRIS showed a mean value of 19.38 (minimum = 4.2, maximum = 41.3, SD = 10.9) for HP-positive patients and a mean value of 0.88 (minimum = 0.10, maximum = 2.5, SD = 0.71) for negative patients. Using a cutoff value corresponding to 0.800% CO2/weight (kg), the 14C-UBT showed a mean value of 2.78 (minimum = 0.89, maximum = 5.22, SD = 1.18) in HP-positive patients. HP-negative patients showed a mean value of 0.37 (minimum = 0.13, maximum = 0.77, SD = 0.17). IRIS is a low-cost, easy to manage, highly sensitive and specific test for H. pylori detection. Storing and mailing the samples did not interfere with the performance of the test.

Immunoexpression of CD95 in chronic gastritis and gastric mucosa-associated lymphomas

CD95 (Fas/APO-1)-mediated apoptosis plays an important role in immunological regulation and is related to the pathogenesis of autoimmune diseases. Immunoexpression of CD95 has been reported to frequently occur in low grade non-Hodgkin lymphomas, especially of post-germinal center histogenesis, among which those originating in mucosa-associated lymphoid tissue (MALT lymphomas). However, there is no report comparing in situ immunoexpression of this marker in lymphomas and the hyperplastic lymphoid reaction (chronic gastritis) related to Helicobacter pylori infection. The purpose of the present research was to compare the intensity of lymphoid CD95 immunoexpression in 15 cases of H. pylori-related chronic gastritis and 15 gastric MALT lymphomas. CD95 (anti-CD95) was detected by an immunoperoxidase technique in paraffin sections using the catalyzed amplification system. Graduation of reaction intensity (percentage of CD95-positive cells) was semiquantitative, from 1+ to 4+. Nine cases of chronic gastritis were 4+, five 2+ and one 1+. Three lymphomas were 4+, three 3+, four 2+, four 1+, and one was negative. Although 14 of 15 lymphomas were positive for CD95, the intensity of the reaction was significantly weaker compared to that obtained with gastric tissue for patients with gastritis (P = 0.03). The difference in CD95 immunoexpression does not seem to be useful as an isolated criterion in the differential diagnosis between chronic gastritis and MALT lymphomas since there was overlapping of immunostaining patterns. However, it suggests the possibility of a pathogenetic role of this apoptosis-regulating protein in MALT lymphomas.

The role of IFN-gamma and IL-4 in gastric mucosa inflammation associated with Helicobacter heilmannii type 1 infection

Although Helicobacter heilmannii infection is less common than H. pylori infection in humans, it is considered to be of medical importance because of its association with gastritis, gastric ulcer, carcinoma, and mucosa-associated lymphoid tissue lymphoma of the stomach. However, there have been no studies evaluating the role of the Th cell response in H. heilmannii gastric infection. We evaluated the participation of pro-inflammatory and anti-inflammatory cytokines, IFN-gamma and IL-4, in H. heilmannii gastric infection in genetically IFN-gamma- or IL-4-deficient mice. The serum IFN-gamma and IL-4 concentrations were determined by ELISA. The gastric polymorphonuclear infiltrate was higher (P = 0.007) in H. heilmannii-positive than in H. heilmannii-negative wild-type (WT) C57BL/6 mice, whereas no significant inflammation was demonstrable in the stomach of H. heilmannii-positive IFN-gamma-/- C57BL/6 mice. The degree of gastric inflammatory cells, especially in oxyntic mucosa, was also higher (P = 0.007) in infected IL-4-/- than in WT BALB/c mice. Serum IFN-gamma levels were significantly higher in IL-4-/- than in WT BALB/c mice, independently of H. heilmannii-positive or -negative status. Although no difference in serum IFN-gamma levels was seen between H. heilmannii-positive (11.3 ± 3.07 pg/mL, mean ± SD) and -negative (11.07 ± 3.5 pg/mL) WT BALB/c mice, in the group of IL-4-/- animals, the serum concentration of IFN-g was significantly higher in the infected ones (38.16 ± 10.5 pg/mL, P = 0.04). In contrast, serum IL-4 levels were significantly decreased in H. heilmannii-positive (N = 10) WT BALB/c animals compared to the negative (N = 10) animals. In conclusion, H. heilmannii infection induces a predominantly Th1 immune response, with IFN-gamma playing a central role in gastric inflammation.

Ureases display biological effects independent of enzymatic activity: Is there a connection to diseases caused by urease-producing bacteria?

Ureases are enzymes from plants, fungi and bacteria that catalyze the hydrolysis of urea to form ammonia and carbon dioxide. While fungal and plant ureases are homo-oligomers of 90-kDa subunits, bacterial ureases are multimers of two or three subunit complexes. We showed that some isoforms of jack bean urease, canatoxin and the classical urease, bind to glycoconjugates and induce platelet aggregation. Canatoxin also promotes release of histamine from mast cells, insulin from pancreatic cells and neurotransmitters from brain synaptosomes. In vivo it induces rat paw edema and neutrophil chemotaxis. These effects are independent of ureolytic activity and require activation of eicosanoid metabolism and calcium channels. Helicobacter pylori, a Gram-negative bacterium that colonizes the human stomach mucosa, causes gastric ulcers and cancer by a mechanism that is not understood. H. pylori produces factors that damage gastric epithelial cells, such as the vacuolating cytotoxin VacA, the cytotoxin-associated protein CagA, and a urease (up to 10% of bacterial protein) that neutralizes the acidic medium permitting its survival in the stomach. H. pylori whole cells or extracts of its water-soluble proteins promote inflammation, activate neutrophils and induce the release of cytokines. In this paper we review data from the literature suggesting that H. pylori urease displays many of the biological activities observed for jack bean ureases and show that bacterial ureases have a secretagogue effect modulated by eicosanoid metabolites through lipoxygenase pathways. These findings could be relevant to the elucidation of the role of urease in the pathogenesis of the gastrointestinal disease caused by H. pylori.

Over-expression of cyclooxygenase-2 in endoscopic biopsies of ectopic gastric mucosa

Ectopic gastric mucosa (EGM) is considered to be a congenital condition. Rare cases of adenocarcinoma have been described. There are no data justifying regular biopsies or follow-up. Cyclooxygenase-2 (COX-2) is a protein involved in gastrointestinal tumor development by inhibiting apoptosis and regulating angiogenesis. The aim of this prospective study was to evaluate COX-2 expression in EGM and compare it with normal tissue and Barrett's esophagus. We evaluated 1327 patients. Biopsies were taken from the inlet patch for histological evaluation and from the gastric antrum to assess Helicobacter pylori infection. Biopsies taken from normal esophageal, gastric antrum and body mucosa and Barrett's esophagus were retrieved from a tissue bank. EGM biopsies were evaluated with respect to type of epithelium, presence of H. pylori, and inflammation. COX-2 was detected by immunohistochemistry using the avidin-biotin complex. EGM islets were found in 14 patients (1.1%). Histological examination revealed fundic type epithelium in 58.3% of cases, H. pylori was present in 50% and chronic inflammation in 66.7%. Expression of COX-2 was negative in normal distal esophagus, normal gastric antrum and normal gastric body specimens (10 each). In contrast, EGM presented over-expression of COX-2 in 41.7% of cases and Barrett's esophagus in 90% of cases (P = 0.04 and 0.03, respectively). COX-2 immunoexpression in EGM was not related to gender, age, epithelium type, presence of inflammation or intestinal metaplasia, H. pylori infection, or any endoscopic finding. Our results demonstrate up-regulation of COX-2 in EGM, suggesting a possible malignant potential of this so-called harmless mucosa.

Expression of TERT in precancerous gastric lesions compared to gastric cancer

The objective of this study was to determine the levels of TERT mRNA and TERT protein expression in stomach precancerous lesions such as intestinal metaplasia (IM) and gastric ulcer (GU) and compare them to gastric cancer (GC). Real-time PCR was performed to detect TERT mRNA expression levels in 35 biopsies of IM, 30 of GU, and 22 of GC and their respective normal mucosas. TERT protein was detected by immunohistochemistry in 68 samples, 34 of IM, 23 of GU, and 11 of GC. Increased TERT mRNA expression levels were observed in a significant number of cases, i.e., 46% of IM, 50% of GU, and 79% of GC. The relative mean level of TERT mRNA after normalization with the β-actin reference gene and comparison with the respective adjacent normal mucosa was slightly increased in the IM and GU groups, 2.008 ± 2.605 and 2.730 ± 4.120, respectively, but high TERT mRNA expression was observed in the GC group (17.271 ± 33.852). However, there were no statistically significant differences between the three groups. TERT protein-positive immunostaining was observed in 38% of IM, 39% of GU, and 55% of GC. No association of TERT mRNA and protein expression with Helicobacter pylori infection or other clinicopathological variables was demonstrable, except for the incomplete type vs the complete type of IM. This study confirms previous data of the high expression of both TERT mRNA and protein in gastric cancer and also demonstrates this type of changed expression in IM and GU, thus suggesting that TERT expression may be deregulated in precursor lesions that participate in the early stages of gastric carcinogenesis.