Differences of urease activity and expression of associated genes according to gastric topography.
BACKGROUND
We hypothesize that pH difference between acid-secreting corpus and non-secreting antrum might influence the activity of H. pylori's urease and/or related genes. We therefore measured urease activity and the expression of amiE whose encoded protein that hydrolyzes short-chain amides to produce ammonia.


METHODS
Fifty-four patients were recruited into this study. Each gastroscopic biopsy specimen collected from the antrum and body of each patient was immediately used to measure urease activity using serial changes of urease activity (ammonia levels) during 60 minutes. Probe specific for amiE was labeled with a biotin nick-translation kit and was used to detect expression of these genes (mRNA) in fresh-frozen gastroscopic biopsy specimens using fluorescent in situ hybridization (FISH).


RESULTS
Urease activity at 60 minutes from the gastric antrum and body of all patients infected with H. pylori was 399.5 ± 490.5 and 837.9 ± 1038.9 μg/dL, respectively (p = .004). Urease activity in the antrum was correlated with H. pylori density. Urease activity or H. pylori density in the antrum was significantly correlated with chronic active inflammation; in contrast, this correlation was not found in the gastric body. The expression level of amiE was 1.5 times higher (p < .05) in the gastric body compared with the antrum.


CONCLUSIONS
Topographically, the urease activity in body was much higher than in antrum. The expression level of amiE was higher in the gastric body compared with the antrum.
Department of Laboratory Medicine, Catholic University, Uijeongbu, Korea.
Hae Kyung
HK
Lee
Hyunjung
H
Kim
Hiun Suk
HS
Chae
Sung Sook
SS
Choi
Hyung Keun
HK
Kim
Young Suk
YS
Cho
Lee So
LS
Maeng
Hee Na
HN
Kim
Kyu Heum
KH
Baik
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000581:Amidohydrolases / Q000096:biosynthesis*; D000641:Ammonia / Q000032:analysis; D001706:Biopsy; D005260:Female; D005773:Gastroscopy; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D013270:Stomach / Q000382:microbiology*; D014510:Urease / Q000096:biosynthesis*
D000641:Ammonia; D000581:Amidohydrolases; C019665:amidase; D014510:Urease