Abstract

BACKGROUND
Helicobacter pylori is present mainly in the gastric mucous layer. However, the mucous layer, along with the bacteria, is lost during conventional tissue processing in which formalin is used for fixation. The purpose of this study is to ascertain - if the mucous layer is preserved by using Carnoy solution as a fixative - whether the detection rate of H. pylori is increased in pediatric patients.
METHODS
Five pieces of gastric mucosal tissue were obtained from the gastric antrum and the body of one hundred pediatric patients. One of the specimens was fixed with formalin. Another specimen was fixed with Carnoy solution. The tissue sections were stained with hematoxylin-eosin and immunohistochemically stained for H. pylori. For reference, a rapid urease test was performed on the remaining three specimens.
RESULTS
In the formalin-fixed tissue, the detection rate of H. pylori was 13% in the gastric antrum and 12% in the body (overall 16%). In the Carnoy solution-fixed tissue, the mucous layer was preserved and the detection rate of H. pylori was 23% in the antrum and 27% in the body (overall 28%). The positive rate of the rapid urease test was 26% in the antrum and 28% in the body (overall 29%).
CONCLUSIONS
When the number of H. pylori is small in the gastric mucosa, the bacteria may not be detected by conventional histologic methods. In that case, the detection rate of H. pylori may be increased by using Carnoy solution, rather than formalin, as a tissue fixative.

• Keywords: Helicobacter pylori;Gastric Mucosa;Fixatives;