• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.264-265
• /
• 2000

Helicobacter pylori(H. pylori) is the causative agent of chronic gastritis and the single most important factor in peptic ulcer disease, however, the pathogenetic mechanisms underlying H, pylori infection are not well understood. Futhermore, there is a strong association between H. pylori infection and gastric cancer. Various diagnostic methods for detecting H. pylori infection are available. These can be divided into invasive methods, requiring endoscopy, and non-invasive tests, mainly 13C-urea breath tests and serologic detection of antibodies. Rapid urease test is the most recommendable endoscopic test for the diagnosis of H. pylori infection, presently. CLO test kit is the represent of rapid urease test kits. The principles of CLO test kit is that hydrolysis of urea by urease Is detected by a dye indicators showing a color change. Our device is used same principle but we improved the reaction time is more faster and positive color change is more distinctive from the color of the negative specimen. So, this kit is more reliable because it response faster and accuracy.

• Proceedings of the Zoological Society Korea Conference
• /
• 1996.10a
• /
• pp.195.1-195
• /
• 1996

No Abstract, See Full Text

• Bulletin of the Korean Chemical Society
• /
• v.23 no.8
• /
• pp.1169-1172
• /
• 2002

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1994.11a
• /
• pp.69-80
• /
• 1994

Although ureases play important roles in microbial nitrogen metabolism and in the pathogenesis of several human diseases, little is known of the mechanism of metallocenter biosynthesis in this Ni-Containing enzyme. Klebsiella aerogenes urease apo-protein was purified from cells grown in the absence of Ni. The purified apo-enzyme showed the same native molecular weight, charge, and subunit stoichiometry as the holo-enzyme. Chemical modification studies were consistent with histidinyl ligation of Ni. Apo-enzyme could not be activated by simple addition of Ni ions suggesting a requirement for a cellular factor. Deletion analysis showed that four accessory genes (ureD, ureE, ureF, and ureG) are necessary for the functional incorporation of the urease metallocenter. Whereas the $\Delta$ureD, $\Delta$ureF, and $\Delta$ureG mutants are inactive and their ureases lack Ni, the $\Delta$ureE mutants retain partial activity and their ureases possess corresponding lower levels of Ni. UreE and UreG peptides were identified by SDS-polyacrylamide gel comparisons of mutant and wild type cells and by N-terminal sequencing. UreD and UreF peptides, which are synthesized at ve교 low levels, were identified by using in vitro transcription/translation methods. Cotransformation of E. coli cells with the complementing plasmids confirmed that ureD and ureF gene products act in trans. UreE was purified and characterized. immunogold electron microscopic studies were used to localize UreE to the cytoplasm. Equilibrium dialysis studies of purified UreE with $^{63}$ NiC1$_2$ showed that it binds ～6 Ni in a specific manner with a $K_{d}$ of 9.6 $\pm$1.3 $\mu$M. Results from spectroscopic studies demonstrated that Ni ions are ligated by 5 histidinyl residues and a sixth N or O atom, consistent with participation of the polyhistidine tail at the carboxyl termini of the dimeric UreE in Ni binding. With these results and other known features of the urease-related gene products, a model for urease metallocenter biosynthesis is proposed in which UreE binds Ni and acts as a Ni donor to the urease apo-protein while UreG binds ATP and couples its Hydrolysis to the Ni incorporation process.ouples its Hydrolysis to the Ni incorporation process.s.

• Journal of Veterinary Clinics
• /
• v.20 no.1
• /
• pp.7-11
• /
• 2003

The selection of a test as a reference with no perfect sensitivity and specificity may lead to bias, yielding distortion of the diagnostic performance. This means it is inappropriate to use imperfect diagnostic tests as a reference method to identify infected patients in clinical environments. In this study, diagnostic performance of rapid urease test, polymerase chain reaction (PCR), and histology of gastric biopsy specimens for diagnosing Helicobacter pylori infection separately and in combination was estimated by using non-linear regression. Based on this approach, the sensitivity, specificity and likelihood ration positive and negative values for each test were as follows: urease test 99.9%, 99.9%, 99.9%, 99.6%, respectively; PCR 88.6%, 99.9%, 99.9%, 70.5%, respectively; histology 78.3%, 97%, 78.3%, 97%, respectively. Predictive values for positive and negative changes with varying Combination of three diagnostic tests employed in the study gives no substantial benefit for practitioners to screen infected patients, and urease test or PCR represents an appropriate single test in clinical environments.

• Proceedings of the KIEE Conference
• /
• 2003.07c
• /
• pp.1938-1940
• /
• 2003

본 연구는 요소 센서 제작을 위한 과정으로서, 전기화학적 방법을 이용한 다공질 실리콘 구조 형성과, PDV(Physical Vapor Deposition) 법에 의한 백금 박막 코팅 및 전기화학적 전도성 고분자 코팅과 urease 고정화 단계를 고찰하고 감도 특성을 제시 하였다. 전극 기질로서 B을 도우핑한 p-type 실리콘웨이퍼를 사용하였고, HF:$C_2H_5OH:H_2O$=1:2:1의 부피비를 갖는 에칭 용액에서 5분간 -7 $mA/cm^2$의 일정 전류를 가하여 폭 2 ${\mu}m$, 깊이 10 ${\mu}m$의 다공질 실리콘(PS) 충을 형성하였다. 그 위에 200 ${\AA}$의 Ti 층을 underlayer로서 증착하고, 2000 ${\AA}$의 Pt를 중착하여 PS/Pt 박막 전극을 제작하고, 전도성 고분자로서 polypyrrole (PPy), 또는 poly(3-mehylthiophene) (P3MT)을 전기화학적으로 코팅한 후, urease(EC 3.5.1.5, type III, Jack Bean, Sigma)를 고정화 하였다. 고정화 시 전해질 수용액의 pH는 7.4로 하여 urease표면이 음전하를 갖도록 하고, 전극에 0.6 V (vs. SCE(Saturated Calomel Electrode))의 일정 전압을 가함으로써 urease가 전도성 고분자 표면에 전기적으로 흡착되도록 하였다. 이상의 방법으로 제작한 요소 센서의 감도는 PPy와 P3MT를 전자 전달 매질로 사용한 경우, 각각 8.44 ${\mu}A/mM{\cdot}cm^2$와 1.55 ${\mu}A/mM{\cdot}cm^2$의 감도를 보였다.

• Journal of Gastric Cancer
• /
• v.9 no.4
• /
• pp.172-176
• /
• 2009

Purpose: The rapid urease test is a rapid and reliable method for diagnosing Helicobacter pylori infection. However it requires gastric mucosal biopsies during endoscopy, and the test is not covered by national health insurance for patients with gastric cancer. So, we introduced an alternative method for a rapid urease test using back-table gastric mucosal biopsies from gastrectomy specimen. Materials and Methods: Ninety gastric cancer patients underwent an anti H. pylori IgG ELISA test and gastrectomy. Just after gastrectomy, two gastric mucosal biopsies from the prepyloric antrum and lower body of the gastrectomy specimen were taken from the back table in the operative room, and these were fixed immediately with the rapid urease test kit, and the color change was monitored for up to 24 hours. In this study, H. pylori infection was defined as positive when the serology or rapid urease test showed positive results. Results: The positive rate of the rapid urease test and serology was 91.1% and 77.8%, respectively. The sensitivity, specificity, positive predictive value and negative predictive value of the rapid urease test and serology were 94.3 and 80.5%, 100 and 100%, 100 and 100%, and 37.5 and 15%, respectively. The accuracy of the rapid urease test was higher than that of serology (94.4 vs. 81.1%, respectively). The rapid urease test showed a higher rate of detecting H. pylori infection than that of serology (McNemar's test, P=0.019). Conclusion: The result of the rapid urease test using back-table gastric mucosal biopsies from a gastrectomy specimen is comparable to the reference data of the conventional rapid urease test using gastric mucosal endoscopic biopsies. Therefore, it can be an alternative diagnostic method for H. pylori infection.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.16 no.1
• /
• pp.34-40
• /
• 2013

Purpose: We investigated the positivity rate and the time period to the positive color change of the urease test in children and adults and assessed the correlation of the urease test to histopathologic findings. Methods: From 1995 to 2000, endoscopic biopsies of the antrum and body were collected from 811 children and 224 adults and subjected to urease tests and histopathology. Results: The positivity rate of the urease test was 49.4% for 0-4 years, 48.4% for 5-9 years, 47.3% for 10-15 years, and 62.5% for 20-29 years in the antrum. The positivity rate was 85.1% in 0-4 years, 82.3% in 5-9 years, 74.7% in 10-15 years, and 74.1% in 20-29 years for the body. In the antrum, the highest positivity rate was <1 hour for the group aged 10-29 years and 6-24 hours in the group <10 years old (p<0.0001). In the body, the highest positivity rate was <1 hour in adults and 6-24 hours in children (p<0.0001). The proportions of the positive reactions within 1 hour were similar for the antrum and the body. In the cases of more severe chronic gastritis, active gastritis, and Helicobacter pylori infiltration, a positive urease test reaction occurred more quickly (p<0.0001). Conclusion: There were significant differences in urease tests according to age and sampling site. The discrepancy between the antrum and the body was greater in younger children. These results might be related to the low density and patchy distribution of bacteria in children and in the body.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.11a
• /
• pp.43-45
• /
• 2004

• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.4
• /
• pp.225-229
• /
• 1993

The objective of this research was to characterize the effect of ammonium thiosulfate(ATS) on soil urease activity and the influence of temperature and soil pH on inhibition of urea hydrolysis by ATS. The results obtained are summarized as follows. 1. Percent inhibition of urea hydrolysis ranged from 1.5~14.3% with 5% addition of ATS to urea to 7.6~20.5% with 10% inclusion at $25^{\circ}C$, which levels were lower than that of thiourea. 2. The effect of ATS on urease inhibition was greater in low temperature han high temperature. The addition of 10% ATS resulted in 62.6% and 41.7% inhibition of urea hydrolysis at $10^{\circ}C$ and $15^{\circ}C$, respectively. 3. The inhibitory effects of ATS were found rapidly or slowly at different soil pH. The inhibition of urease activity was showed after 24 hours at pH 6.0 and 6.5, while the hydrolysis of urea was inhibited by ATS after 48 hourse at pH 5.0, 7.0 and 7.5. Urea hydrolysis inhibitions after 72 hours incubation were similar at all pH tested. Therefore effects of ATS did not correlate with soil pH.