Biomedical subjects
Niall P Breslin
Publications and source records attributed to Niall P Breslin.
Helical CT versus EUS with fine needle aspiration for celiac nodal assessment in patients with esophageal cancer.
BACKGROUND: Conventional CT is insensitive for detection of metastatic involvement of celiac lymph nodes in esophageal cancer. Helical CT has theoretical advantages over "slice" CT in this regard, but its performance has not yet been prospectively studied. METHODS: Consecutive patients with untreated esophageal cancer were recruited after obtaining informed consent. Helical CT was performed on all patients and TNM staging was performed by a single radiologist. Subsequently, all patients underwent esophageal radial and, as needed, curvilinear array EUS with fine needle aspiration (FNA), for evaluation of celiac lymph nodes and TNM staging. Test performance characteristics with 95% confidence intervals were calculated, assuming EUS with FNA as the reference standard. RESULTS: Forty-eight patients were recruited, of whom 37 (77%) were men. The mean (SD) age was 63.6 (10) years. Excluding 5 patients in whom a confirmatory FNA was not available (n = 43), helical CT identified celiac lymph nodes in 12 (28%) patients. The reference standard of EUS with FNA identified 15 (35%) patients with metastatic celiac lymph nodes, giving a sensitivity, specificity, and positive and negative predictive values for helical CT of 53% (95% CI [28%, 79%]), 86% (95% CI [73%, 99%]), 67% (95% CI [40%, 93%]), and 77% (95% CI [63%, 92%]), respectively, for assessing celiac lymph nodal involvement. The sensitivity and specificity of helical CT in detecting T4 disease were 25% (95% CI [3.8%, 46%]) and 94% (95% CI [85%, 100%]), respectively. There were 12 patients (25%; 95% CI [13%, 37%]) who were felt to have resectable disease by helical CT but had either metastatic involvement of celiac lymph nodes or T4 disease by EUS/FNA. CONCLUSIONS: Despite technological advances, helical CT still appears unreliable, mainly because of insensitivity, for the identification of inoperable T4 or metastatic involvement of celiac lymph node disease in esophageal cancer.
Omeprazole increases permeability across isolated rat gastric mucosa pre-treated with an acid secretagogue.
Triple therapy using proton-pump inhibitors (PPIs) in combination with oral antibiotics for the treatment of Helicobacter pylori-associated gastritis has shown increased efficacy for reasons that are still poorly understood. Possible explanations include a direct antibacterial effect of the PPIs or a PPI-mediated increase in bacterial susceptibility to antibiotics. Using an in-vitro model of rat gastric mucosa, we examined fluxes of a radiolabelled marker molecule through the interepithelial tight junctions under normal conditions and under the influence of an acid secretagogue (50 microM histamine) and a PPI (100 microM omeprazole). Paracellular fluxes of the radiolabel (represented by calculation of apparent permeability coefficients) were linear over 2 h. Fluxes of the marker increased significantly after treatment with histamine followed by omeprazole, but were unaltered in paired preparations exposed to the same drugs given in reverse order. Enhancements in paracellular permeability were mirrored in separate experiments using a detergent (Triton X-100), a bile salt (deoxycholate) and an agent that disrupts the cytoskeleton (cytochalasin D) to interfere with tight junctional integrity. The results suggest that exposure of acid-secreting gastric mucosa to omeprazole widens the interepithelial spacing in a manner that may facilitate enhanced macromolecular transport. Increases in antibiotic delivery from the blood to the gastric lumen via such a mechanism may account for the greater eradication rates observed with PPI-based triple therapy in H. pylori-associated gastritis.