Detection of Helicobacter pylori infection of the gastric mucosa by measurement of gastric aspirate ammonium and urea concentrations.

Abstract

Helicobacter pylori possesses unusually high urease activity that lowers the urea concentration and raises the ammonium concentration of the gastric juice in infected people. The value of measuring urea and ammonium concentrations in gastric juice obtained during upper gastrointestinal endoscopy as a means of diagnosing the presence and eradication of the infection was assessed. Twenty four subjects with the infection and 14 in whom it had been eradicated were examined. Their Hpylori status was confirmed by antral biopsy and 14C urea breath test. The median (range) gastric juice urea concentration in infected subjects was 0-8 mmol/I (0.5-2.9 mmol/l), which was lower than th9t in the uninfected subjects (2.1 mmolIl ,(1I0-3-7 mmol/l)) (p<0001). The median gastric juice ammonium concentration in infected subjects was 3.4 mmol/l (10-13-0 mmol/l), which was higher than that in the uninfected subjects (0.64 mmol/l (0.02-1.4 mmol/l)) (p<0001). Though the two groups overlapped in respect of their urea and ammonium concentrations, they were completely different when the urea: ammonium ratios were calculated -the ratios ranged from 0 04-0*7 (median 0.26) and from 1-1-113 (median 3.4) in infected and uninfected subjects respectively (p<0001

<i>Mt 21-42</i>: Development and Validation of an Automatic Device Proposed for the Endoscopic Diagnosis of <i>Helicobacter pylori</i> Infection and Atrophic Gastritis

“…In this study, the authors reported a strong correlation between the presence of the bacterium and the levels of ammonium. Subsequently, several other reports have been published on this topic [9,10,11,12,13,14,15,16,17,18]. Most of them confirmed the relation between ammonium and infection but they significantly differed about the concentrations detected (table 2); moreover, an evident overlap between infected and uninfected patients occurred in all studies.…”

“…Moreover, the peculiar characteristic of gastric juice makes this determination much more problematic than in other mediums. This may account for the discrepancies reported in the literature about this parameter and its possible role in diagnosing H. pylori infection [8,9,10,11,12,13,14,15,16,17,18]. …”

“…Although individual evaluations have not been performed, the cumulative effect of long persistence at room temperature, freezing and centrifugation has proven to modify the measurement of pH and ammonium. This aspect may be account for the differences reported in the literature about gastric juice pH and, in particular, ammonium determination [10, 11, 13, 14,16,17,18]. …”

Ammonia as an Accelerator of Tumor Necrosis Factor Alpha-Induced Apoptosis of Gastric Epithelial Cells in Helicobacter pylori Infection

“…Neithercut et al (12) reported that the median ammonia concentration in gastric juice of H. pylori-infected subjects was 3.4 mM (range, 1.0 to 13.0 mM), which was higher than that in uninfected subjects (0.64 mM [range, 0.02 to 1.4 mM]). In the present study, 2 to 4 mM exogenously added ammonia raised the frequency of apoptosis from around 3% at background to 10 to 40%, respectively (Fig.…”

Determination of Ammonia in Exhaled Breath by Flow Injection Analysis with Electrochemical Detection

“…2831 Thus, concentration of ammonia in exhaled breath of human who is infected by Helicobacter pylori is elevated after administration of urea compared with before. 5,31 In this study, the determination of ammonia in the exhaled breath of urease administrated gerbils before and after ingesting urea was carried out to examine whether the elevation of ammonia in exhaled breath was monitored by the present FIA-ECD system As shown in Fig. 6A, the ammonia concentration in the exhaled breath of urease administrated gerbils after urea administration was elevated in comparison with that in the exhaled breath of the negative control gerbils and urease administrated gerbils before urea administration.…”