• YAKHAK HOEJI
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• v.43 no.2
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• pp.180-197
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• 1999

Acute and subacute oral toxicity of $HELIKIT^{TM}$ ($^{13}C-urea$) were carried out in Sprague-Dawley rats of both sex. The toxicity of $HELIKIT^{TM}$ was compared with urea($^{12}C-urea$ which is used for control). In acute toxicity studies, we daily examined number of deaths, clinical signs, body weights and pathological examination for 14 days after single oral administration of HELIKIT or urea($^{12}C-urea$) at a dose of 5000 mg/kg. The subacute oral toxicity was investigated in Sprague-Dawley rats treated with $HELIKIT^{TM}$ at a dose of 40, 200 and 1,000 mg/kg/day or $^{12}C-urea$ at a dose of 1,000 mg/kg/day for 4 weeks. In acute toxicity studies, $HELIKIT^{TM}$ and urea did not show any toxic effect in rats and oral LD50 value was over 5,000 mg/kg rats. In subacute toxicity studies, no death occured and no drug-related changes were found in clinical observations; body weight, food consumption, opthalmoscopy. auditory test, urinalysis, hematology, blood chemistry, gross pathological examination or organ weight between $HELIKIT^{TM}$, urea and control groups. In histopathological examinations, the slight thickening of mucosa of the limiting ridge in the stomach was noted in the animals treated with $HELIKIT^{TM}$ at a dose of 1,000 mg/kg/day and also the changes in urea group at a dose of 1,000 mg/kg/day was found, but all of these changes in the changes in ures group at a dose of 1,000 mg/kg/days was found, but all of these changes in the stomach regressed after withdrawal of the test article for 2 weeks and reversibility of the effect was revealed. These results indicate that the non toxic dose level of $HELIKIT^{TM}$ was 1,000 mg/kg/day in the 4 weeks-repeated dose study, suggesting that the substitution of $^{13}C$ for carbon in urea molecule has no effect on the toxicity of urea and changes in stomach are reversible.

• Biomolecules & Therapeutics
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• v.6 no.4
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• pp.406-411
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• 1998

The pre-mixed $_{13}C$-urea powder preparation in ${Helikit}_{TM}$ for test of Helicobacter pylori was evaluated for pharmacological properties. The oral doses of the preparation used in mice were 30-fold as compared to human doses. The results obtained in the present study demonstrate that spontaneous movement, hexobarbital-induced hypnosis, rotarod performance, body temperature, acetic acid-induced writhing syndrome, chemical and electroshock convulsion, pupil size and intestinal propulsion had not been affected at the oral doses of 230, 700 and 2100 mg/kg in mice. The blood pressure was slightly elevated as given intravenously in rats at a dose of 5 mg/kg of the preparation, but respiration was not influenced at the dose. In isolated guinea pig ileum and rat fundus preparation, the preparation at a concentration of $1{\times}10^{4}$ g/ml neither caused any direct effect nor inhibited the contraction produced by acetylcholine, histamine or 5-hydroxytryptamine. These results reported here provide evidence that pre-mixed $^{13}C$ 13/C-urea powder preparation is free of general pharmacological properties performed in oral administration.

• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.268-272
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• 2006

Purpose : The reinfection rate of H. pylori reported before $^{13}C$-urea breath test($^{13}C$-UBT) era was higher than that of the post $^{13}C$-UBT era. Children are usually reluctant to receive invasive endoscopic evaluation for the reinfection of H. pylori, particularly when they are asymptomatic. The aim of the study is to discover the reinfection rate by different diagnostic tests, and to find out what causes the difference. Methods : Children confirmed to be eradicated from H. pylori were included in the study. Reinfection was evaluated by endoscopic biopsy based tests(n=34, mean age $11.5{\pm}3.7$ years) and/or a $^{13}C$-UBT(n=38, mean age $10.0{\pm}3.6$ years) at the time of 18 months after eradication. At first visit, H. pylori infection had been diagnosed by positive results from a rapid urease test, Giemsa stain and Warthin-Starry stain and/or a positive culture. Eradication was defined as negative results from all above tests 1-3 months after eradication therapy. Results : Reinfection rate by endoscopic biopsy based tests was 35.3 percent(12/34). All patients had abdominal symptoms(P=0.000). Reinfection rate was 13.2 percent(5/38) by a $^{13}C$-UBT. Reinfection rate was higher in children with abdominal symptoms(P=0.008). There was no evidence that reinfection rate depended on the sex(P=0.694), age(P=0.827), diseases(peptic ulcers vs gastritis, P=0.730) and eradication regimen(P=0.087). Conclusion : Helocibacter pylori reinfection rate in Korean children was 13.2 percent per 18 months by a non-invasive test or $^{13}C$-UBT. Accurate determinations of the reinfection rate in children is affected by the compliance of the diagnostic tests. Non-invasive tests should be considered to investigate the reinfection rate in children.