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Sample records for c-urea breath test

  1. 14C-urea breath test for the detection of Helicobacter pylori

    NARCIS (Netherlands)

    Veldhuyzen van Zanten, S. J.; Tytgat, K. M.; Hollingsworth, J.; Jalali, S.; Rshid, F. A.; Bowen, B. M.; Goldie, J.; Goodacre, R. L.; Riddell, R. H.; Hunt, R. H.

    1990-01-01

    The high urease activity of Helicobacter pylori can be used to detect this bacterium by noninvasive breath tests. We have developed a 14C-urea breath test which uses 5 microCi 14C with 50 mg nonradioactive urea. Breath samples are collected at baseline and every 30 min for 2 h. Our study compared

  2. 14C-urea breath test for the detection of Helicobacter pylori

    International Nuclear Information System (INIS)

    Veldhuyzen van Zanten, S.J.; Tytgat, K.M.; Hollingsworth, J.; Jalali, S.; Rshid, F.A.; Bowen, B.M.; Goldie, J.; Goodacre, R.L.; Riddell, R.H.; Hunt, R.H.

    1990-01-01

    The high urease activity of Helicobacter pylori can be used to detect this bacterium by noninvasive breath tests. We have developed a 14 C-urea breath test which uses 5 microCi 14 C with 50 mg nonradioactive urea. Breath samples are collected at baseline and every 30 min for 2 h. Our study compared the outcome of the breath test to the results of histology and culture of endoscopically obtained gastric biopsies in 84 patients. The breath test discriminated well between the 50 positive patients and the 34 patients negative for Helicobacter pylori: the calculated sensitivity was 100%, specificity 88%, positive predictive value 93%, and negative predictive value 100%. Treatment with bismuth subsalicylate and/or ampicillin resulted in lower counts of exhaled 14 CO 2 which correlated with histological improvement in gastritis. The 14 C-urea breath test is a better gold standard for the detection of Helicobacter pylori than histology and/or culture

  3. The fate of ingested [sup 14]C-urea in the urea breath test for Helicobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Munster, D J; Chapman, B A; Burt, M J; Dobbs, B R; Allardyce, R A; Bagshaw, P F; Troughton, W D; Cook, H B [Christchurch Hospital (New Zealand)

    1993-08-01

    The metabolic fate of the radioactive carbon in the [sup 14]C-urea breath test for Helicobacter pylori was investigated in 18 subjects. After ingestion of labelled urea, breath was sampled for 24 h, and urine was collected for 3 days. Subjects were designated high or low expirers on the basis of their breath counts, and this agreed well with H. pylori serologic analyses. When given 185 or 37 kBq of [sup 14]C-urea, 51% of the label was recovered from the breath of high expirers, and 7% from the breath of low expirers. The mean combined urinary and breath recovery for high expirers was 86%, and for low expirers it was 97%. It is concluded that the long-term retention of [sup 14]C from ingested [sup 14]C-urea is low. The results enable a more accurate estimation to be made of radiation exposure resulting from the [sup 14]C-urea breath test. 16 refs., 3 figs., 2 tabs.

  4. 13C-urea breath test analyzed with infrared isotope spectrometry for the diagnosis of Helicobacter pylori

    International Nuclear Information System (INIS)

    Dahlberg, M.; Schoensby, H.

    1998-01-01

    The authors have evaluated a 13 C-urea breath test for the diagnosis of Helicobacter pylori infection. The 13 C-test was analyzed with isotope-selective non-dispersive infrared spectrometry and compared with a 14 C-urea breath test and the urease test in gastric mucosal biopsies. 46 patients were analyzed with breath tests, 23 patients were negative and 22 patients were positive with both methods. One patients was positive with 14 C-method and negative with the 13 C-urea breath test. 61 patients were analyzed with the 13 C-urea breath test and the urease test. 30 patients were negative and 30 patients were positive with both methods, whereas one patient with a negative urease test had a positive breath test. 13 C-urea breath test analyzed with isotope-selective non-dispersive infrared spectrometry is a fast, simple, non-radioactive, non-invasive, convenient and reliable method for the diagnosis of Helicobacter pylori infection. 12 refs., 2 figs., 1 tab

  5. Validation of 14 C-urea breath test for diagnosis of Helicobacter pylori

    International Nuclear Information System (INIS)

    Mattar, Rejane; Silva, Fernando Marcuz; Alexandrino, Ana Maria; Laudanna, Antonio Atilio

    1999-01-01

    The aim of this study was to validate the 14 C-urea breath test for use in diagnosis of Helicobacter pylori infection. Thirty H. pylori positive patients, based on histologic test and thirty H. pylori negative patients by histology and anti-H pylori IgG entered the study. Fasting patients drank 5 uCi of 14 C-urea in 20 ml of water. Breath samples were collected at O, 5, 10, 15, 20 and 30 min. The difference of cpm values between the two groups was significant at all the time intervals, besides time 0 (p 14 C-urea breath test is highly accurate for Helicobacter pylori diagnosis. It is fast, simple and should be the non-invasive test used after treating Helicobacter pylori infection. (author)

  6. The 14C-urea breath-test for the detection of gastric Campylobacter pylori infection

    International Nuclear Information System (INIS)

    Surveyor, I.; Goodwin, C.S.; Mullan, B.P.; Geelhoed, E.; Warren, J.R.; Murray, R.N.; Waters, T.E.; Sanderson, C.R.

    1989-01-01

    Sixty-three patients who were undergoing endoscopy were studied. The radioactivity in exhaled breath which was sampled within five minutes of 14 C -urea administration was attributed to the presence of urease enzyme in mouth organisms and was discounted. The time-radioactivity curves for breath samples from five to 30 minutes after the administration of 14 C-urea gave an excellent separation between subjects with negative results of the examination of gastric-biopsy samples and patients with microbiological and histological evidence of infection with Campylobacter (C.) pylori. The area under the time-radioactivity curve at between five and 30 minutes after the administration of 14 C-urea in 24 patients with negative microbiological results was 6.9±4.4 area units; in 35 of 39 patients with positive microbiological results, this area was greater than 40 area units. Measured against the results of the microbiological examination of gastricbiopsy samples, the sensitivity of breath-testing was 90% and the specificity was 100%. Measured against the results of histological examination for the presence of C. pylori infection, breath-testing had a sensitivity of 94% and a specificity of 93%. A positive breath-test result also correlated well (P=0.0001) with the serological antibody test-result. The role of non-invasive tests - enzyme-linked immunosorbent assays and 14 C-urea breath-testing - in the management of gastritis and peptic ulcer disease is discussed. We consider that the 14 C-urea breath-test has an important role in the noninvasive confirmation of gastric infection with C. pylori and in the follow-up of patients after treatment. 38 refs., 2 figs., 1 tab

  7. Comparison of Accuracy Between 13C- and 14C-Urea Breath Testing: Is an Indeterminate-Results Category Still Needed?

    Science.gov (United States)

    Charest, Mathieu; Bélair, Marc-André

    2017-06-01

    Helicobacter pylori infection is the leading cause of peptic ulcer disease. The purpose of this study was, first, to assess the difference in the distribution of negative versus positive results between the older 14 C-urea breath test and the newer 13 C-urea breath test and, second, to determine whether use of an indeterminate-results category is still meaningful and what type of results should trigger repeated testing. Methods: A retrospective survey was performed of all consecutive patients referred to our service for urea breath testing. We analyzed 562 patients who had undergone testing with 14 C-urea and 454 patients who had undergone testing with 13 C-urea. Results: In comparison with the wide distribution of negative 14 C results, negative 13 C results were distributed farther from the cutoff and were grouped more tightly around the mean negative value. Distribution analysis of the negative results for 13 C testing, compared with those for 14 C testing, revealed a statistically significant difference between the two. Within the 13 C group, only 1 patient could have been classified as having indeterminate results using the same indeterminate zone as was used for the 14 C group. This is significantly less frequent than what was found for the 14 C group. Discussion: Borderline-negative results do occur with 13 C-urea breath testing, although less frequently than with 14 C-urea breath testing, and we will be carefully monitoring differences falling between 3.0 and 3.5 %Δ. 13 C-urea breath testing is safe and simple for the patient and, in most cases, provides clearer positive or negative results for the clinician. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

  8. The sup 14 C-urea breath-test for the detection of gastric Campylobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Surveyor, I; Goodwin, C S; Mullan, B P; Geelhoed, E; Warren, J R; Murray, R N; Waters, T E; Sanderson, C R [Royal Perth Hospital (Australia)

    1989-10-16

    Sixty-three patients who were undergoing endoscopy were studied. The radioactivity in exhaled breath which was sampled within five minutes of {sup 14}C -urea administration was attributed to the presence of urease enzyme in mouth organisms and was discounted. The time-radioactivity curves for breath samples from five to 30 minutes after the administration of {sup 14}C-urea gave an excellent separation between subjects with negative results of the examination of gastric-biopsy samples and patients with microbiological and histological evidence of infection with Campylobacter (C.) pylori. The area under the time-radioactivity curve at between five and 30 minutes after the administration of {sup 14}C-urea in 24 patients with negative microbiological results was 6.9{plus minus}4.4 area units; in 35 of 39 patients with positive microbiological results, this area was greater than 40 area units. Measured against the results of the microbiological examination of gastricbiopsy samples, the sensitivity of breath-testing was 90% and the specificity was 100%. Measured against the results of histological examination for the presence of C. pylori infection, breath-testing had a sensitivity of 94% and a specificity of 93%. A positive breath-test result also correlated well (P=0.0001) with the serological antibody test-result. The role of non-invasive tests - enzyme-linked immunosorbent assays and {sup 14}C-urea breath-testing - in the management of gastritis and peptic ulcer disease is discussed. We consider that the {sup 14}C-urea breath-test has an important role in the noninvasive confirmation of gastric infection with C. pylori and in the follow-up of patients after treatment. 38 refs., 2 figs., 1 tab.

  9. Validation of {sup 14} C-urea breath test for diagnosis of Helicobacter pylori

    Energy Technology Data Exchange (ETDEWEB)

    Mattar, Rejane; Silva, Fernando Marcuz; Alexandrino, Ana Maria; Laudanna, Antonio Atilio [Sao Paulo Univ., SP (Brazil). Hospital das Clinicas. Dept. de Gastroenterologia]. E-mail: shiroineko@uol.com.br

    1999-02-01

    The aim of this study was to validate the {sup 14} C-urea breath test for use in diagnosis of Helicobacter pylori infection. Thirty H. pylori positive patients, based on histologic test and thirty H. pylori negative patients by histology and anti-H pylori IgG entered the study. Fasting patients drank 5 uCi of {sup 14} C-urea in 20 ml of water. Breath samples were collected at O, 5, 10, 15, 20 and 30 min. The difference of cpm values between the two groups was significant at all the time intervals, besides time 0 (p < 0.0001). At 20 min, the test gave 100% sensitivity and specificity with a cut-off value of 562 cpm. Females were higher expirers than males (p=0.005). {sup 14} C-urea breath test is highly accurate for Helicobacter pylori diagnosis. It is fast, simple and should be the non-invasive test used after treating Helicobacter pylori infection. (author)

  10. The microdose rapid 14C urea breath test compares well with the original rapid 14 breath test

    International Nuclear Information System (INIS)

    Bellon, M.S.; Bartholomeusz, F.D.L.; Chatterton, B.E.

    2000-01-01

    Full text: The 14 C urea breath test (CUBT) is a sensitive test used in the detection of H. pylori infection. The rapid 14 CUBT using 185 KBq of 14 C urea showed a sensitivity of 100% when tested in 36 patients. The aim of this study was to compare the results of the 14 CUBT performed following the ingestion of 37KBq microdose 14 C urea capsule (Bicapsule, Trimed) with the earlier method which uses 185 KBq 14 C urea. 19 patients (nine female age 21-52 yrs) were studied. All subjects first underwent a 14 CUBT with the microdose capsule and a single 15 minute post ingestion sample. An hour later the test was repeated but with a dose of 185 KBq 14 C urea in liquid form. A normal result was taken as 2 = 0.92). This is shown above. The Rapid 14 CUBT performed following the microdose capsule whilst reducing patient radiation exposure is an accurate test for the detection of H. pylori. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  11. How reliable are the sup 14 C-urea breath test and specific serology for the detection of gastric campylobacter

    Energy Technology Data Exchange (ETDEWEB)

    Husebye, E; O' Leary, D; Skar, V; Melby, K [Ullevaal Sykehus, Oslo (Norway)

    1990-01-01

    Detection of gastric campylobacter by the {sup 14}C-urea breath test and serology were correlated to biopsy culture in 25 unselected outpatients referred for gastroscopy. All the 17 culture-positive patients had positive {sup 14}C-urea breath test, and 16 had positive serology. Of eight culture-negative patients, six patients had negative breath test and seven negative serology. A high degree of reproducibility was found when two subsequent breath tests were performed in 11 healthy volunteers. The breath test values obtained at 10 min showed a strong correlation to the accumulated values within 30 min. Breath sampling once, 10 min after intake of 2.5 {mu}Ci {sup 14}C-urea, seems sufficient for the detection of gastric campylobacter. The {sup 14}C-urea breath test correlates well with biopsy culture and provides a sensitive tool for the detection of gastric campylobacter. Serology also corresponds well with biopsy culture and should provide a useful tool for epidemiologic studies. 22 refs., 4 figs., 1 tab.

  12. A methodological aspect of the 14C-urea breath test used in Helicobacter pylori diagnosis

    International Nuclear Information System (INIS)

    Kopanski, Z.; Niziol, J.; Micherdzinski, J.; Wasilewska-Radwanska, M.; Cienciala, A.; Lasa, J.; Witkowska, B.

    1996-01-01

    The main purpose of those investigations was optimisation of the performing time of the breath test with 14 C-labelled urea which reveals Helicobacter pylori infection. It was analysed 117 species, preselected according to endoscopy and histopathology results, 56 of them have suffered from chronic gastritis and 61 from gastric ulcer disease. Using microbiology diagnosis (culture + IFP test) it was found that 86 species were H. pylori infected. This group of patients were next subject to investigations with the breath test with 14 C-labelled urea. Measurements of radioactivity of breathe air have been carried out for 30 minutes. The obtained results allow us to maintain that the optimal time of duration of the test described above is 30 minutes. (author)

  13. Clinical investigation of 14C-urea breath test

    International Nuclear Information System (INIS)

    Yu Yongli; Zhu Ruisen; Ji Hong; Luo Quanyong

    2000-01-01

    To investigate clinical value of 14 C-urea breath test ( 14 C-UBT) for the diagnosis of Helicobacter pylori(Hp), 70 patients were both performed gastroscopy (taking gastric mucosae biopsy for rapid urease test and histology) and 14 C-UBT (some patients by Hp-IgG or DNAHp test also) within two days. The positive cases of both rapid urease test and histology was defined as 'gold standard' of Hp-positive, whereas the negative cases of both rapid urease test and histology as 'gold standard' of Hp-negative. The sensitivity of 14 C-UBT was 93.2%, the specificity 73.1%, and the diagnostic accuracy 85.7%. The difference (comparing with 'gold standard') was not marked (x 2 = 0.9 0.05(1) 2 = 3.84, P>0.05). But the diagnostic accuracy of 14 C-UBT (85.7%) and Hp-IgG (50%) had a marked difference (x 2 13.80>x 0.01(1) 2 = 6.64, P 14 C-UBT was easy to operate, reliable and suitable for clinical application

  14. 14C-urea breath test in the detection of Helicobacter pylori infection

    International Nuclear Information System (INIS)

    Artiko, V.M.; Obradovic, V.B.; Petrovic, N.S.; Davidovic, B.M.; Grujic-Adanja, G.S.; Nastic-Miric, D.R.; Milosavljevic, T.N.

    2001-01-01

    Helicobacter pylori infection is supposed to be one of the major causes of digestive and other diseases. Among a lot of invasive and non-invasive methods for its detection, none is ideal. The aim is an assessment of the Helicobacter pylori infection in the stomach using breath test and comparison to other diagnostic methods, as well as following up the effects of therapy. In 17 patients with digestive discomfort, breath test, rapid urease test and histology were performed, while in 47 patients with proven HP infection the effect of therapy was followed up using breath test and clinical findings. Breath test was performed after per oral administration of the capsule of 14 C urea (37 kBq). Findings of the breath and urease tests were in accordance in 14/17 patients (83%) while breath test and histology in 16/17 patients (94%). During follow-up of the therapeutic effects, breath test and clinical findings were in accordance in 43/47 patients (98%). Breath test can be useful in diagnosis but is a method of choice in following up the patients after therapy for H. pylori infection, because it is non-invasive, fast and precise. (author)

  15. Accuracy of non-invasive 13C-urea breath test compared to invasive tests for helicobacter pylori detection

    International Nuclear Information System (INIS)

    Bilal, R.; Khaar, B.; Omar, M.; Qureshi, T.Z.; Ahmed, T.; Latif, Z.; Jaffery, I.; Omar, M.

    2007-01-01

    To compare the sensitivity, specificity and Positive Predictive Value (PPV) of histology, Campylobacter-Like Organism (CLO) test, culture and 13C-Urea Breath Test (UBT) for the diagnosis of Helicobacter pylori infection. District Headquarter Hospital, Rawalpindi, Military Hospital, Rawalpindi and Pakistan Institute of Science and Technology (PINSTECH), Nilore, Islamabad from June 2002 to 2003. Three mucosal biopsy specimens were obtained during endoscopy of 90 symptomatic patients. Histology, CLO test and culture were performed on these specimens. Breath samples for 13C-UBT were collected and sent to RIAD, PINSTECH on the same day for isotope ratio mass spectrometry. For analysis purpose, each of the tests was fixed as the gold standard in turn and the others were then compared against it. In addition, any two as well as any three positive tests were then set as the gold standard and the other tests compared against them to calculate the sensitivity, specificity, accuracy and PPV of other tests. Urea breath test had the highest sensitivity, ranging from 95 to 100%, against all the gold standards with specificity ranging from 55 to 100%, whereas the sensitivity of histological examination was around 98% but it had comparatively lower specificity (49-89%). The CLO test had a sensitivity range of 86-100% and specificity of 67-100%. Culture had the minimum sensitivity (59-70%) but had highest specificity (96-100%) against all the gold standards. Age and gender had no effect on p-value of each test or in combination. The urea breath test has shown the highest ability to detect the organism with 95-100% sensitivity in symptomatic individuals and specificity, which is comparable to other tests. (author)

  16. Accuracy of the 14 C-urea breath test for the diagnosis of Helicobacter pylori

    International Nuclear Information System (INIS)

    Gomes, Ana Thereza Britto; Secaf, Marie; Modena, Jose Luiz Pimenta; Troncon, Luiz Ernesto de Almeida; Oliveira, Ricardo Brandt de

    2002-01-01

    The development of simple, accurate and low-expense techniques for detection of Helicobacter pylori infection has great relevance. The objective was to determine the accuracy of a rapid 14 C-urea breath test (UBT) employing a very simple device for breathed air collection. One hundred and thirty-seven adult patients who underwent upper gastrointestinal endoscopy in the Clinical Hospital. The main measurements were histology for Helicobacter pylori (HP); urease test; urea breath test (UBT). One hundred and fifteen patients were infected by HP (HP +) according to both histology and the urease test, and 22 patients were HP-negative (HP-), according to the same two tests. UBT was capable of discriminating between HP + and HP- in a way that was similar to the combination of urease test and histology. When this combination of results is taken as the 'gold standard' for HP infection, the sensitivity and specificity of UBT are both greater than 90% for a range of cut-off points and breathed air collection times. It was concluded that the rapid UBT employing a simple device for air collection has a high accuracy in determining HP infection. (author)

  17. Prevalence of Helicobacter Pylori in gastric cancer in a south-east Asian population by 14C-urea breath test

    International Nuclear Information System (INIS)

    Chung, A.Y-F; Chow, P.K.H.; Yu, W-K.; Ho, J.M.S.; Chan, H-S.; Wong, W-K.; Soo, K-C.

    2001-01-01

    Helicobacter pylori is believed to play an important role in the aetiology of gastric cancer. There is a great variability in seropositivity and histological frequency of H. pylori in gastric cancer. The present prospective study investigates the prevalence of H. pylori infection in gastric cancer patients using 14C-urea breath testing. Patients with endoscopic biopsy-proven gastric cancer were fasted for 6 h prior to ingesting 18.5 x 104 Bq of 14C-urea cocktail orally. Breath samples were collected after 20 min by AS/King them to blow into a hyamine solution and measurements were read in a scintillation counter. Fifty out of 51 patients (98%) with gastric cancer were positive on the 14C-urea breath test compared to 29 patients (61%) who were positive on histology. There was no association between sex, age or tumour site, stage, differentiation, Lauren type and H. pylori status. The test was negative in one patient with cardiac tumour in which histology of the resected specimen was also negative for the bacteria. Active H. pylori infection is highly prevalent in gastric cancer in a South-East Asian population. The 14C-urea breath test is a highly sensitive method for detecting the presence of H. pylori even in gastric adenocarcinoma irrespective of the stage

  18. Confirmation of eradication of Helicobacter pylori infection by 14C-urea breath test

    International Nuclear Information System (INIS)

    Pathak, C.M.; Bhasin, D.K.; Sharma, B.C.; Roy, P.; Vaiphei, K.

    1998-01-01

    Helicobacter pylori (H. pylori) is a potent urease producer, a characteristic that has been exploited in the development of the 14 C-urea breath test (UBT). 14 C-UBT is being used as a highly reliable test for the diagnosis of H. pylori infection. There is paucity of reports on the utility of this test to confirm the H. pylori eradication after its treatment. The study was conducted to determine the utility of 14 C-UBT in confirming the eradication of H. pylori

  19. Microdose 14C urea breath test for the diagnosis of Helicobacter pylori: a survey in Iranian population

    Directory of Open Access Journals (Sweden)

    Reza Dowlatabadi Bazaz

    2005-01-01

    Full Text Available The carbon -14 urea breath test (UBTis a non-invasive and simple method for the diagnosis of Helicobacter pylori infection. Attempts have been made to use lower doses of 14C-urea in the UBT in order to reduce the radiation risk of the test. The aim of this study was to assess the accuracy of a microdose (1 µCi [37 KBq] 14C-UBT in Iranian population for validation of its diagnostic accuracy against gold standard methods. Eighty and two patients were subjected to upper gastrointestinal endoscopy as well as 14C-UBT in one week. Rapid urease test and histological examinations were used as gold standard. Breath samples were collected 10, 20 and 30 minute after ingestion of 1 µCi of 14C- urea solution and their activities were measured using a scintillation counter and expressed as counts per minute (cpm and disintegration per minute (dpm. Good agreement was observed between the 14C-UBT and gold standard for samples which were collected 20 minutes after 14C-urea administration. The 14CUBT showed 100% sensitivity, 95% specificity, 95.45% positive predictive value, 100% negative predictive value and 97.50% accuracy. The results of this study showed good concordance between the 14C-UBT and invasive methods.

  20. Utilization of urea micro dose with 14 C in breath test to detect the Helicobacter pylori

    International Nuclear Information System (INIS)

    Chausson, Yvon; Coelho, Luiz Gonzaga V.; Passos, Maria do Carmo F.; Andrade, Angela A.M.; Simal, Carlos J.R.; Paula Castro, Luiz de; Fernandes, M.L.; Yazaki, F.R.

    1995-01-01

    A lower dose is used in the 14 C-urea breath test to detect the Helicobacter pylori (Hp). Such dose produce trivial radiation doses. The results shown that the use of this desirable dose is possible. (author). 4 refs., 1 fig

  1. UREA BREATH TEST – ITS ROLE IN DIAGNOSTICS

    Directory of Open Access Journals (Sweden)

    Joško Osredkar

    2004-01-01

    Full Text Available Background. Each year many patients visit their physicians complaining of digestive symptoms, most commonly functional dyspepsia (»indigestion« or gastroesophageal reflux (»heartburn«. However, many patients with abdominal discomfort are actually suffering from gastric or duodenal ulcers that are commonly caused by H. pylori and thus are curable. Clearing the infection usually heals the ulcer and prevents relapse, so an accurate diagnosis is important. There are several options for diagnosing H. pylori infection: serology to detect antibodies against the bacterium; endoscopic biopsy for urease testing (H. pylori produce a urease that breaks down urea to ammonia and carbon dioxide; histology with special stains; or culture. Unfortunately, these procedures are invasive, expensive and not always accurate. Serological tests require a blood sample and tell only that a patient has been exposed to H. pylori at some time in the past, but not whether the patient is currently infected. Endoscopy and biopsy can detect current infection — the CLO test urease test allows rapid detection of H. pylori in gastric biopsy specimens — but endoscopy and biopsy are unpleasant medical procedures.Recently, noninvasive, sensitive, specific, easy to perform and patient’s well accepted methods had been developed known as urea breath test (UBT. When an infected person swallows a dose of urea labeled with an isotope of carbon — carbon-13 (13C or carbon-14 (14C – H. pylori in the gastric mucosa break down the labeled urea to form ammonia and labeled carbon dioxide. The carbon dioxide is absorbed into the bloodstream and excreted via the lungs. The patient then exhales into a device that measures the level of carbon dioxide. The urea breath test is specific for H. pylori (it detects only urease-producing bacteria, it is sensitive (the labeled urea reaches a large area of the stomach and thus reflects total gastric urease activity and the results can be

  2. The clinical value of 14C-urea breath test for diagnosis of helicobacter pylori infection

    International Nuclear Information System (INIS)

    Zhang Shuwen; Zhang Yongxian; Zhang Jinming; Ding Yong; Shao Mingzhe; Liu Zilai; Tian Jiahe

    2003-01-01

    The purpose of this study is to evaluate a rapid microdose 14 C-urea breath test ( 14 C-UBT) with a simplified protocol for detecting the infection of helicobacter pylori (HP). 244 fasting patients with upper gastrointestinal symptoms undergo the 14 C-UBT and 124 cases appear positive. 89 patients of those undergo upper gastrointestinal endoscopy and confirmed as HP infection. The sensitivity and specificity of the 14 C-UBT is 100% when compared with the endoscopy. The test has good diagnostic accuracy with minimal radiation exposure and low cost. Thus, the test is reliable, safe, convenient and cost-effective to clinical use

  3. Reduction of sources of error and simplification of the Carbon-14 urea breath test

    International Nuclear Information System (INIS)

    Bellon, M.S.

    1997-01-01

    Full text: Carbon-14 urea breath testing is established in the diagnosis of H. pylori infection. The aim of this study was to investigate possible further simplification and identification of error sources in the 14 C urea kit extensively used at the Royal Adelaide Hospital. Thirty six patients with validated H. pylon status were tested with breath samples taken at 10,15, and 20 min. Using the single sample value at 15 min, there was no change in the diagnostic category. Reduction or errors in analysis depends on attention to the following details: Stability of absorption solution, (now > 2 months), compatibility of scintillation cocktail/absorption solution. (with particular regard to photoluminescence and chemiluminescence), reduction in chemical quenching (moisture reduction), understanding counting hardware and relevance, and appropriate response to deviation in quality assurance. With this experience, we are confident of the performance and reliability of the RAPID-14 urea breath test kit now available commercially

  4. MIN 14C UBT: A combination of gastric basal transit and 14C-urea breath test for the detection of helicobacter pylori infection in human beings

    International Nuclear Information System (INIS)

    Zubillaga, M.; Oliveri, P.; Calcagno, M.L.; Goldman, C.; Caro, R.; Mitta, A.; Degrossi, O.; Boccio, J.

    1997-01-01

    The purpose of this work is to demonstrate that the 14 C-urea breath test (UBT) performed at different times combined with the study of the gastric basal transit, which evaluates the intragastric displacement of a labeled solution under fasting conditions, has the advantage of being representative of the whole stomach surface and constitutes a non-aggressive test for the detection of H. pylori. This test, which has been called MIN 14 C UBT, is a modification of the conventional 14 C UBT in which low volumes of a solution of 14 C-urea together with 99m Tc-sulfur colloid are administered. The 99m Tc-sulfur colloid is not absorbed in the gastrointestinal tract and has the great advantage of allowing the 'visualization' of the transit of the 14 C-urea within the gastrointestinal tract. This modification allows the simultaneous determination of the production of the 14 CO 2 and the place where this process occurs. The results show that there is a good correlation between the images obtained and the breath samples collected. We found that this test has a sensitivity of 98% and a specificity of 96% for H. pylori detection

  5. First-time urea breath tests performed at home by 36,629 patients

    DEFF Research Database (Denmark)

    Dahlerup, Søren; Andersen, Rikke Charlotte; Nielsen, Birgitte Sperling Wilms

    2011-01-01

    BACKGROUND: The aim of the current study was (1) to describe the use of a (13) C-urea breath test (UBT) that was performed by patients at their homes as a part of a test-and-treat strategy in primary care and (2) to investigate the prevalence of Helicobacter pylori in patients taking a first...

  6. Validation of a simplified carbon-14-urea breath test for routine use for detecting Helicobacter pylori noninvasively

    International Nuclear Information System (INIS)

    Henze, E.; Malfertheiner, P.; Clausen, M.; Burkhardt, H.; Adam, W.E.

    1990-01-01

    A carbon-14 ( 14 C) urea breath test for detecting Helicobacter pylori with multiple breath sampling was developed. Carbon-14-urea (110 kBq) administered orally to 18 normal subjects and to 82 patients with Helicobacter infection. The exhaled 14 C-labeled CO 2 was trapped at 10-min intervals for 90 min. The total 14 C activity exhaled over 90 min was integrated and expressed in %activity of the total dose given. In normals, a mean of 0.59% +/- 0.24% was measured, resulting in an upper limit of normal of 1.07%. In 82 patients, a sensitivity of 90.2%, a specificity of 83.8%, and a positive predictive value of 90.2% was found. The single probes at intervals of 40-60 min correlated best with the integrated result, with r ranging from 0.986 to 0.990. The test's diagnostic accuracy did not change at all when reevaluated with the 40-, 50-, or 60-min sample data alone. Thus, the 14 C-urea breath test can be applied routinely as a noninvasive, low-cost and one-sample test with high diagnostic accuracy in detecting Helicobacter pylori colonization

  7. Optoacoustic 13C-breath test analyzer

    Science.gov (United States)

    Harde, Hermann; Helmrich, Günther; Wolff, Marcus

    2010-02-01

    The composition and concentration of exhaled volatile gases reflects the physical ability of a patient. Therefore, a breath analysis allows to recognize an infectious disease in an organ or even to identify a tumor. One of the most prominent breath tests is the 13C-urea-breath test, applied to ascertain the presence of the bacterium helicobacter pylori in the stomach wall as an indication of a gastric ulcer. In this contribution we present a new optical analyzer that employs a compact and simple set-up based on photoacoustic spectroscopy. It consists of two identical photoacoustic cells containing two breath samples, one taken before and one after capturing an isotope-marked substrate, where the most common isotope 12C is replaced to a large extent by 13C. The analyzer measures simultaneously the relative CO2 isotopologue concentrations in both samples by exciting the molecules on specially selected absorption lines with a semiconductor laser operating at a wavelength of 2.744 μm. For a reliable diagnosis changes of the 13CO2 concentration of 1% in the exhaled breath have to be detected at a concentration level of this isotope in the breath of about 500 ppm.

  8. Application of 13C-urea breath test in patients diagnosed as H. pylori-negative by gastroscopy

    International Nuclear Information System (INIS)

    Li Long; Liu Changjiang; Gao Jianqing; Xu Sumei; Chen Linna; Zhou Jianming

    2006-01-01

    13 C-urea breath test( 13 C-UBT)was used to evaluate infection rate of H. pylori(HP) and effect of HP eradication in patients diagnosed as HP-negative by histology and rapid urease test. Patiens without gastrointestinal disorders were set as control group. Within 640 patients diagnosed as HP-negative by histology and rapid urease test, there were 389 patients showed HP-positive by 13 C-UBT. The positive rate of HP was 60.8%. 389 patients diagnosed as HP- positive by 13 C-UBT were treated with PPI-based triple therapy, PPI-based double therapy and single PPI therapy, respectively. After treatment, the negative rate of 13 C-UBT was 83.8%, 18.4% and 3.3%, respectively. The results showed significant difference between three kinds of therapy (P 13 C-UBT could improve the diagnostic rate of HP to patients who diagnosed as HP-negative by histology and rapid urease test. (authors)

  9. {sup 14}C urea breath test kit- an evaluation of a compact, cost-effective kit for the detection of H. pylori

    Energy Technology Data Exchange (ETDEWEB)

    Bellon, M.S. [Royal Adelaide Hospital, SA (Australia). Dept of Nuclear Medicine

    1998-03-01

    Full text: Helicobacter pylori infection of the gastric mucosa causes active chronic gastritis and peptic ulceration. Carbon-14 urea breath testing has been well documented in its ability to detect the presence of H. pylori. The aims of this study were to evaluate and refine the test to substantially reduce costs and improve its simplicity, availability and accuracy. We reviewed the results of 138 patients who underwent {sup 14}C urea breath testing for the detection of H. pylori utilising a kit developed at the Royal Adelaide Hospital. Modifications to the standard technique that were assessed included the relevance of buccal cleansing, single sample v multiple sampling, use of alternative CO{sub 2} absorbers and sampling techniques. In those patients with positive biopsy results, a test sensitivity of 100% was achieved. No buccal cleansing is necessary (45% oral contamination without brushing teeth v 41% with). A single breath sample only at 15 min resulted in 100% sensitivity. Alternative (cheaper and safer) CO{sub 2} absorbers such as KOH can be used. Based on these results, modifications to this well documented test have enabled us to substantially reduce costs, improve simplicity and safety and increase accuracy and availability of the test for the detection of Helicobacter pylori.

  10. "VALIDATION OF 13C-UREA BREATH TEST WITH NON DISPERSIVE ISOTOPE SELECTIVE INFRARED SPECTROSCOPY FOR THE DIAGNOSIS OF HELICOBACTER PYLORI INFECTION: A SURVEY IN IRANIAN POPULATION"

    Directory of Open Access Journals (Sweden)

    "Davood Beiki

    2005-04-01

    Full Text Available The urea breath test (UBT which is carried out with 13C or 14C labeled urea is one of the most important non invasive methods for detection of Helicobacter pylori infection. Application of 13C-UBT is becoming increasingly popular because of its non radioactive nature which makes it suitable for diagnostic purposes in children and women of child bearing ages. While isotope ratio mass spectrometer (IRMS is generally used to detect 13C in expired breath, this instrument is expensive and recently non dispersive isotope selective infrared (NDIR spectroscopy which is a lower cost technique has been employed as a reliable counterpart for IRMS in small clinics. The aim of this study was to assess the validity of NDIR spectroscopy technique in Iranian population in comparison with histological examination, rapid urease test and 14C-urea breath test as gold standard. Seventy six patients with dyspepsia were underwent 13CUBT for diagnosis of Helicobacter pylori infection. Good agreements were found between the 13C-UBT and gold standard methods. The 13C-UBT showed 100% sensitivity, 97.3% specificity, 97.56% positive predictive value, 100% negative predictive value and 98.65% accuracy. On the basis of these results it could be concluded that 13C-UBT performed with NDIR spectroscopy is a reliable, accurate and non invasive diagnostic tool for detection of Helicobacter pylori infection in the Iranian population.

  11. Turnover of carbon in the 13C-urea breath test for the detection of Helicobacter pylori infection

    International Nuclear Information System (INIS)

    Costa, Vladimir E.; Andreazzi, Mariana; Cury, Caio S.; Bassetto Junior, Carlos A.Z.; Rodrigues, Maria A.M.; Ducatti, Carlos

    2013-01-01

    To obtain a standard protocol for the application of 13 C-urea breath test ( 13 C-UBT) analyzed by Isotope Ratio Mass Spectrometer (IRMS) to detect helicobacter pylori infection in the population is necessary to know the behavior of the turnover of 13 C during the test in different individuals. The aims of this study was to find out a pattern for the turnover of the 13 C in the 13 C-UBT, analyzed by IRMS, in patients infected with H. pylori, in a Brazilian population, to define a protocol test application. We found that the isotopic ratio 13 C/ 12 C in expired CO 2 from patients infected with H. pylori and subjected to 13 C-UBT does not follow a single pattern of behavior. However this behavior can be similar in subjects having the same maximum values following an inverse proportional relationship between the maximum value and the time of appearance in the curve. (author)

  12. Can the C-14 urea breath test reflect the extent and degree of ongoing helicobacter pylori infection

    International Nuclear Information System (INIS)

    Lim, Seok Tae; Sohn, Myung Hee; Lee, Seung Ok; Lee, Soo Taik; Jeong, Myung Ja

    2001-01-01

    The C-14 urea breath test (C-14 UBT) is the most specific noninvasive method to detect Helicobacter (H) pylori infection. We investigated if the C-14 UBT can reflect the presence and degree of H. pylori detected by gastroduodenoscopic biopsies (GBx). One hundred fifty patients (M:F=83:67,age 48.6±11.2 yrs) underwent C-14 UBT, rapid urease test (CLO test) and GBx on the same day. For the C-14 UBT, a single breath sample was collected at 10 minutes after ingestion of C-14 urea (137 KBq) capsule and counting was done in a liquid scintillation counter for 1 minute, and the results were classified as positive (≥200 dpm), intermediate ( 50 ∼ 199 dpm) or negative ( < 50 dpm). The results of CLO tests were classified as positive or negative according to color change. The results of GBx on giemsa stain were graded 0 (normal) to 4(diffuse) according to the distribution of H. pylori by the Wyatt method. We compared C-14 UBT results with GBx grade as a gold standard. In the assessment of the presence of H. pylori infection, the C-14 UBT global performance yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 92.5%, 88.4%, 97.1%, 88.4% and 91.3%, respectively. However, the CLO test had sensitivity, specificity, PPV, NPV and accuracy of 83.2%, 81.4%, 91.8%, 81.4% and 82.7%, respectively. The quantitative values of the C-14 UBT were 45 ± 27 dpm in grade 0, 707 ±584 dpm in grade 1, 1558±584 dpm in grade 2, 1851±604 dpm in grade 3, and 2719 ± 892 dpm in grade 4. A significant correlation (r=0.848, p<0.01) was found between C-14 UBT and the grade of distribution of H. pylori infection on GBx with giemsa stain. We conclude that the C-14 UBT is a highly accurate, simple and noninvasive method for the diagnosis of ongoing H. pylori infection and reflects the degree of bacterial distribution

  13. A methodological aspect of the {sup 14}C-urea breath test used in Helicobacter pylori diagnosis; Wybrany aspekt metodologiczny testu oddechowego z mocznikiem znakowanym stosowanego w diagnostyce zakazenia Helicobacter pylori

    Energy Technology Data Exchange (ETDEWEB)

    Kopanski, Z.; Niziol, J.; Micherdzinski, J.; Wasilewska-Radwanska, M.; Cienciala, A.; Lasa, J.; Witkowska, B. [Szpital Wojskowy, Cracow (Poland)]|[Institute of Physics and Nuclear Techniques, Academy of Mining and Metallurgy, Cracow (Poland)]|[Institute of Nuclear Physics, Cracow (Poland)

    1996-12-31

    The main purpose of those investigations was optimisation of the performing time of the breath test with {sup 14}C-labelled urea which reveals Helicobacter pylori infection. It was analysed 117 species, preselected according to endoscopy and histopathology results, 56 of them have suffered from chronic gastritis and 61 from gastric ulcer disease. Using microbiology diagnosis (culture + IFP test) it was found that 86 species were H. pylori infected. This group of patients were next subject to investigations with the breath test with {sup 14}C-labelled urea. Measurements of radioactivity of breathe air have been carried out for 30 minutes. The obtained results allow us to maintain that the optimal time of duration of the test described above is 30 minutes. (author) 38 refs, 2 tabs, 1 fig

  14. Study on Urea Breath Test (UBT) a tool for helicobacter pylori infection

    International Nuclear Information System (INIS)

    Kolekar, R.V.; Bhade, S.P.D.; Reddy, Priyanka; Singh, Rajvir; Gadgil, Anita; Bhandarkar, Prashant; Roy, N.; Patil, S.P.

    2016-01-01

    Helicobacter pylori commonly called as H. pylori resides in the gastric epithelial mucosa and induces an inflammatory response leading to gastritis, peptic nicer disease and gastric malignancies. Detection and eradication of H.pylori infection is thus an important measure to prevent these. H.pylori has a worldwide prevalence rate of about 50%, with a higher prevalence in developing countries. Urea breath test, an outpatient noninvasive technique achieves up to 95% sensitivity and specificity at half the cost compared to histology, in detecting H. Pylori infection. Indian studies on the use of UBT and its standard protocol are sparse. The present paper discusses the application of Carbon-14 Urea breath test for the diagnosis of H pylori bacterial infection in 261 adult patients

  15. Turnover of carbon in the {sup 13}C-urea breath test for the detection of Helicobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Vladimir E.; Andreazzi, Mariana; Cury, Caio S.; Bassetto Junior, Carlos A.Z.; Rodrigues, Maria A.M.; Ducatti, Carlos, E-mail: vladimir@ibb.unesp.br, E-mail: ducatti@ibb.unesp.br, E-mail: mariana.andreazazi@gmail.com, E-mail: caiocury@hotmail.com, E-mail: juniorbassett@hotmail.com, E-mail: mariar@fmb.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil)

    2013-07-01

    To obtain a standard protocol for the application of {sup 13}C-urea breath test ({sup 13}C-UBT) analyzed by Isotope Ratio Mass Spectrometer (IRMS) to detect helicobacter pylori infection in the population is necessary to know the behavior of the turnover of {sup 13}C during the test in different individuals. The aims of this study was to find out a pattern for the turnover of the {sup 13}C in the {sup 13}C-UBT, analyzed by IRMS, in patients infected with H. pylori, in a Brazilian population, to define a protocol test application. We found that the isotopic ratio {sup 13}C/{sup 12}C in expired CO{sub 2} from patients infected with H. pylori and subjected to {sup 13}C-UBT does not follow a single pattern of behavior. However this behavior can be similar in subjects having the same maximum values following an inverse proportional relationship between the maximum value and the time of appearance in the curve. (author)

  16. The effect of radioactive iodine treatment on 14C urea breath test results in patients with hyperthyroidism.

    Science.gov (United States)

    Arduc, Ayse; Dogan, Bercem Aycicek; Ozuguz, Ufuk; Tuna, Mazhar Muslim; Gokay, Ferhat; Tutuncu, Yasemin Ates; Isik, Serhat; Aydin, Yusuf; Peksoy, Irfan; Berker, Dilek; Guler, Serdar

    2014-12-01

    Radioactive Iodine therapy (RAIT) plays a major role in the treatment of hyperthyroidism. In addition to the thyroid gland, significant amounts of radioactive iodine are maintained in the stomach. The aim of this study was to determine if RAIT has any effect on Helicobacter pylori infection, based on the C urea breath test (UBT). The study included 85 patients with hyperthyroidism scheduled to undergo RAIT and 69 hyperthyroid subjects in whom methimazole treatment was planned. All subjects had pretreatment-positive UBT results, and the test was repeated on the first and third months after RAIT and methimazole treatment. After a mean RAIT dose of 15 mCi (range, 10-20 mCi), UBT became negative in 13 (15.3%) of 85 patients on the first month and 18 (21.2%) of 85 patients on the third month. All subjects treated with methimazole remained UBT positive on the first and third months of methimazole treatment (100%). Reduction in the number of UBT-positive patients on both the first and the third months after RAIT was statistically significant (P hyperthyroidism etiologies and thyroid autoantibody levels in subjects with UBT that became negative and in subjects with UBT that remained positive were similar in the RAIT group (P > 0.05). Urea breath test negativity rates did not differ according to the radioiodine dose. Our findings indirectly showed that RAIT might have an antimicrobial effect on H. pylori. Clinical applications of this beneficial effect of RAIT on H. pylori should be further evaluated.

  17. Investigation of the association between glaucoma and Helicobacter pylori infection using the 14C-urea breath test

    International Nuclear Information System (INIS)

    Tuzcu, Esra Ayhan; Aydogan, Fusun; Motor, Vicdan Koksaldi; Ilhan, Ozgur; Daglioglu, Mutlu Cihan; Coskun, Mesut; Parlakfikirer, Nihan; Keskin, Ugurcan

    2015-01-01

    Purpose: to investigate the association between glaucoma and Helicobacter pylori infection by evaluating for the presence of H. pylori infection in patients with glaucoma using the 14C-urea breath test (14C-UBT). Methods: Using 14C-UBT, H. pylori infection positivity was compared between a group of patients with primary open-angle glaucoma and a control group with normal intraocular pressure and a normal optic disc or normal perimetry. Results: the 14C-UBT was positive in 18 (51.42%) out of 35 patients in the glaucoma group and in 15 (42.85%) out of 35 patients in the control group. H. pylori infection positivity rates were similar between the glaucoma and control groups (p>0.05). Conclusion: according to the 14C-UBT, there is no association between primary open-angle glaucoma and H. pylori infection. (author)

  18. Carbon-14 urea breath test for the diagnosis of Campylobacter pylori associated gastritis

    International Nuclear Information System (INIS)

    Marshall, B.J.; Surveyor, I.

    1988-01-01

    Urease in the human gastric mucosa is a marker for infection with Campylobacter pylori (CP), an organism suspected of causing chronic gastritis and peptic ulceration. To detect gastric urease, we examined 32 patients who were being evaluated for possible peptic ulcer disease. Fasting patients were given 10 microCi (370 kBq) of 14 C-labeled urea. Breath samples were collected in hyamine at intervals between 1 and 30 min. The amount of 14 C collected at these times was expressed as: body weight X (% of administered dose of 14 C in sample)/(mmol of CO 2 collected). The presence of C. pylori colonization was also determined by examination of multiple endoscopic gastric biopsy specimens. On average, patients who were proven to have C. pylori infection exhaled 20 times more labeled CO 2 than patients who were not infected. The difference between infected patients and C. pylori negative control patients was highly significant at all time points between 2 and 30 min after ingestion of the radionuclide (p less than 0.0001). The noninvasive urea breath is less expensive than endoscopic biopsy of the stomach and more accurate than serology as a means of detecting Campylobacter pylori infection. Because the test detects actual viable CP organisms, it can be used to confirm eradication of the bacterium after antibacterial therapy

  19. Biokinetics and radiation dosimetry of 14C-labelled triolein, urea, glycocholic acid and xylose in man. Studies related to nuclear medicine 'breath tests' using accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Gunnarsson, Mikael

    2002-08-01

    14 C-labelled substances have been used in biomedical research and clinical medicine for over 50 years. Physicians and scientists however, often hesitate to use these substances in patients and volunteers because the radiation dosimetry is unclear. In this work detailed long-term biokinetic and dosimetric estimation have been carried out for four clinically used 14 C-breath tests: 14 C-triolein (examination of fat malabsorption), urea (detection of Helicobacter pylori infection in the stomach), glycocholic acid and xylose (examination of bacterial overgrowth in the small intestine) by using the highly sensitive accelerator mass-spectrometry (AMS) technique. The AMS technique has been used to measure low 14 C concentrations in small samples of exhaled air, urine, faeces and tissue samples and has improved the base for the estimation of the absorbed dose to various organs and tissues and the effective dose to man. The high sensitivity of the AMS system has also made it possible to perform 14 C breath tests on patient groups which were earlier subject for restriction (e.g. small children). In summary, our results show that for adult patients - and in the case of 14 C-urea breath test also for children down to 3 years of age - the dose contributions are comparatively low, both described as organ doses and as effective doses. For adults, the latter is: 14 C-glycocholic acid - 0.4 mSv/MBq, 14 C-triolein - 0.3 mSv/MBq, 14 C-xylose - 0.1 mSv/MBq and 14 C-urea - 0.04 mSv/MBq. Thus, from a radiation protection point of view there is no reason for restrictions in using any of the 14 C-labelled radiopharmaceutical included in this work in the activities normally used (0.07-0.2 MBq for a 70 kg patient)

  20. Investigation of the association between glaucoma and Helicobacter pylori infection using the {sup 14}C-urea breath test

    Energy Technology Data Exchange (ETDEWEB)

    Tuzcu, Esra Ayhan; Aydogan, Fusun; Motor, Vicdan Koksaldi; Ilhan, Ozgur; Daglioglu, Mutlu Cihan; Coskun, Mesut; Parlakfikirer, Nihan; Keskin, Ugurcan, E-mail: drayhant@hotmail.com [Medical Faculty, Mustafa Kemal University, Hatay (Turkey)

    2015-07-01

    Purpose: to investigate the association between glaucoma and Helicobacter pylori infection by evaluating for the presence of H. pylori infection in patients with glaucoma using the 14C-urea breath test (14C-UBT). Methods: Using 14C-UBT, H. pylori infection positivity was compared between a group of patients with primary open-angle glaucoma and a control group with normal intraocular pressure and a normal optic disc or normal perimetry. Results: the 14C-UBT was positive in 18 (51.42%) out of 35 patients in the glaucoma group and in 15 (42.85%) out of 35 patients in the control group. H. pylori infection positivity rates were similar between the glaucoma and control groups (p>0.05). Conclusion: according to the 14C-UBT, there is no association between primary open-angle glaucoma and H. pylori infection. (author)

  1. Biokinetics and radiation dosimetry of {sup 14}C-labelled triolein, urea, glycocholic acid and xylose in man. Studies related to nuclear medicine 'breath tests' using accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gunnarsson, Mikael

    2002-08-01

    {sup 14}C-labelled substances have been used in biomedical research and clinical medicine for over 50 years. Physicians and scientists however, often hesitate to use these substances in patients and volunteers because the radiation dosimetry is unclear. In this work detailed long-term biokinetic and dosimetric estimation have been carried out for four clinically used {sup 14}C-breath tests: {sup 14}C-triolein (examination of fat malabsorption), urea (detection of Helicobacter pylori infection in the stomach), glycocholic acid and xylose (examination of bacterial overgrowth in the small intestine) by using the highly sensitive accelerator mass-spectrometry (AMS) technique. The AMS technique has been used to measure low {sup 14}C concentrations in small samples of exhaled air, urine, faeces and tissue samples and has improved the base for the estimation of the absorbed dose to various organs and tissues and the effective dose to man. The high sensitivity of the AMS system has also made it possible to perform {sup 14}C breath tests on patient groups which were earlier subject for restriction (e.g. small children). In summary, our results show that for adult patients - and in the case of {sup 14}C-urea breath test also for children down to 3 years of age - the dose contributions are comparatively low, both described as organ doses and as effective doses. For adults, the latter is: {sup 14}C-glycocholic acid - 0.4 mSv/MBq, {sup 14}C-triolein - 0.3 mSv/MBq, {sup 14}C-xylose - 0.1 mSv/MBq and {sup 14}C-urea - 0.04 mSv/MBq. Thus, from a radiation protection point of view there is no reason for restrictions in using any of the {sup 14}C-labelled radiopharmaceutical included in this work in the activities normally used (0.07-0.2 MBq for a 70 kg patient)

  2. 14C-urea breath test as a method to detect Campylobacter pylori colonization

    NARCIS (Netherlands)

    Rauws, E. A.; van Royen, E. A.; Tytgat, G. N.

    1989-01-01

    Campylobacter pylori may cause type B gastritis. C. pylori produces urease, and the presence of this enzyme in gastric mucosal biopsies is a marker for colonization with the microorganism. The value of a breath test to detect C. pylori colonization in non-ulcer dyspepsia patients was investigated.

  3. The 13carbon urea breath test for the diagnosis of Helicobacter pylori infection in subjects with atrophic gastritis: evaluation in a primary care setting

    NARCIS (Netherlands)

    Korstanje, A.; van Eeden, S.; Offerhaus, G. J. A.; Sabbe, L. J. M.; den Hartog, G.; Biemond, I.; Lamers, C. B. H. W.

    2006-01-01

    BACKGROUND: (13)Carbon urea breath testing is reliable to detect current infection with Helicobacter pylori but has been reported to be of limited value in selected patients with atrophic body gastritis or acid-lowering medication. AIM: To evaluate the accuracy of (13)carbon urea breath testing for

  4. Comparison between the 13C-urea breath test and stool antigen test for the diagnosis of childhood Helicobacter pylori infection

    International Nuclear Information System (INIS)

    Kato, Seiichi; Minoura, Takanori; Iinuma, Kazuie; Konno, Mutsuko; Tajiri, Hitoshi; Matsuhisa, Takeshi

    2004-01-01

    As noninvasive tests for Helicobacter pylori infection, the 13 C-urea breath test (UBT) and stool antigen test have been widely used. In children, however, there are few studies reporting which test shows superior performance. The purpose of this study was to compare the 13 C-UBT and stool antigen test for their accuracy in diagnosing. H. pylori infection in children. A total of 123 Japanese children, ages 2 to 17 years (mean, 12 years) who underwent gastric biopsies for H. pylori infection were studied. The diagnoses included gastritis (n=55), gastric ulcer (n=5), duodenal ulcer (n=20), iron-deficiency anemia (n=7), and other conditions (n=36). The cutoff value of the 13 C-UBT was defined to be 3.5 per mille. The stool antigen test was performed using the H. pylori stool antigen (HpSA) enzyme-linked immunosorbent assay (ELISA) (Premier Platinum HpSA). In 16 patients who received eradication therapy, the 13 C-UBT and HpSA were repeated 2 months after treatment. Based on biopsy tests, 60 children were infected with H. pylori and 63 children were not. For the 13 C-UBT, the sensitivity, specificity, and accuracy were 95.0% (95% confidence interval [CI], 86.1%-99.0%), 98.4% (95% CI, 91.5%-100%), and 96.4% (95% CI, 93.6%-99.9%), respectively. For the HpSA, the sensitivity, specificity, and accuracy were 983.% (95% CI, 90.8%-100%), 98.4% (95% CI, 91.2%-100%), and 98.3% (95% CI, 96.0%-100%), respectively. There were no significant differences between the performance of these two tests. In the assessment of H. pylori eradication, the results of 13 C-UBT and HpSA agreed with those of biopsy tests. The 13 C-UBT and the HpSA are equally accurate for the diagnosis of active H. pylori infection in Japanese children. (author)

  5. Validation of ten-minute single sample carbon-14 urea breath test for diagnosis of Helicobacter pylori infection

    International Nuclear Information System (INIS)

    Prabakaran, K.; Fernandes, V.; McDonald, J.

    1996-01-01

    Helicobacter pylori infection is traditionally diagnosed by endoscopy followed by gastric biopsy and histologic demonstration of organisms, rapid urease test and culture. The non-invasive carbon-14-urea breath test has been widely accepted now for the diagnosis of this bacterium. This study was aimed to establish and validate normal and abnormal values for an Australian population, for a single sample carbon-14-urea breath test at ten minutes. A dose of 185 kBq was used in order to achieve reasonable counting statistics. The derived values were validated with the results of the rapid urease test. This method has a high sensitivity, specificity and greater patient acceptance, and could be used in many clinical settings as the first modality for the diagnosis of H. pylori infection and for documenting response or cure after antibiotic therapy for eradication. 11 refs., 1 tab., 4 figs

  6. Validación de método simplificado de la prueba en aliento con urea-13C para diagnóstico de infección por Helicobacter pylori Validation of a simplified method of the 13C urea breath test for diagnosis of Helicobacter pylori

    Directory of Open Access Journals (Sweden)

    N. X. Ortiz-Olvera Nayeli

    2007-07-01

    Full Text Available Objetivo: validar un método simplificado de la prueba en aliento con urea-13C (PAU-13Cs para el diagnóstico de infección por Helicobacter pylori (H. pylori, con administración simultánea de 50 mg de urea-13C y 2 g de ácido cítrico. Material y métodos: se estudiaron 88 pacientes (49 mujeres y 39 hombres; con promedio de edad 45 ± 15 años, referidos para endoscopia gastrointestinal y toma de biopsias. La PAU-13Cs se realizó en ayuno. Se recolectaron las muestras de aire espirado en tubos de cristal de 10 ml, antes y 30 minutos después de administrar simultáneamente 50 mg de urea-13C y 2 g de ácido cítrico disueltos en 200 ml de agua. Las muestras se analizaron por espectrometría de masas. El diagnóstico de infección se consideró cuando el cultivo y/o la biopsia y serología fueron positivas para H. pylori. Resultados: cincuenta y un pacientes (57,95% fueron positivos, 30 (34,10% negativos para H. pylori y 7 (7,95% casos se consideraron indeterminados. La sensibilidad, especificidad, valor predictivo positivo y negativo de PAU-13Cs fue de 90,2, 93,3, 95,8 y 84,8%, respectivamente. Con exactitud de 91,4%. Conclusión: la administración simultánea de 50 mg de urea-13C y 2 g de ácido cítrico, representa una alternativa para el diagnóstico no invasivo de infección por H. pylori, debido a que conserva la certeza diagnóstica de la PAU-13C.Objective: to validate a simplified 13C-urea breath test (13C-UBT method for the diagnosis of H. pylori infection. Material and methods: patients referred for gastrointestinal endoscopy and biopsy were included, and a 13C-UBT was performed after a 6-hour fast. Breath samples were collected in 10 ml glass tubes before and 30 min after the simultaneous administration of 50 mg of 13C-urea and 2 g of citric acid in 200 ml of water. All breath samples were analyzed using isotope ratio mass spectrometry. The diagnosis of H. pylori infection was established with a positive culture and/or positive

  7. The Relationship Between 14C Urea Breath Test Results and Neutrophil/Lymphocyte and Platelet/Lymphocyte Ratios

    Directory of Open Access Journals (Sweden)

    Ertan Şahin

    2018-04-01

    Full Text Available Aim: Neutrophil/lymphocyte ratio (NLR and platelet/lymphocyte ratio (PLR are used as inflammatory markers in several diseases. However, there are little data regarding the diagnostic ability of NLR and PLR in Helicobacter pylori. We aimed to assess the association between the 14C urea breath test (14C-UBT results and NLR and PLR in H. pylori diagnosis. Methods: Results of 89 patients were retrospectively analysed in this study. According to the 14C-UBT results, patients were divided into two groups: H. pylori (+ and H. pylori (- (control group. Haematological parameters, including hemoglobine, white blood cell (WBC count, neutrophil count, lymphocyte count, NLR, platelet count, and PLR were compared between the two groups. Results: The mean total WBC count, neutrophil count, NLR and PLR in H. pylori (+ patients were significantly higher than in the control group (p<0.001 for all these parameters. In the receiver operating characteristic curve analysis, the cut-off value for NLR and PLR for the presence of H. pylori was calculated as ≥2.39 [sensitivity: 67.3%, specificity: 79.4%, area under the curve (AUC: 0.747 (0.637-0.856, p<0.0001] and ≥133.3 [sensitivity: 61.8%, specificity: 55.9%, AUC: 0.572 (0.447-0.697, p<0.05], respectively. Conclusion: The present study shows that NLR and PLR are associated with H. pylori positivity based on 14C-UBT, and they can be used as an additional biomarker for supporting the 14C-UBT results.

  8. Ten years experience of isotopic breath test with special reference to Helicobacter pylori detection

    Energy Technology Data Exchange (ETDEWEB)

    Verhas, M.; Tricht, L.Van; Verschaeren, A.; Delmotte, E.; Martin, P

    1997-12-31

    The use of the carbon 14 urea breath test by comparison with culture for campylobacter of gastric endoscopic biopsies is studied in 91 patients. They were divided into 2 groups. The first group consisted of 53 patients examined by gastric endoscopy and carbon 14 urea breath test. In this population, gastric biopsies were taken at different regions of the stomach and duodenum. The breath test was performed within 3 hours after endoscopy. The second group consisted of 38 asymptomatic patients whom 23 were parent of children with campylobacter positive gastritis. For the whole population, neither antibiotic therapy nor bismuth medication was administrated within the 15 days before the realization of the test. Results were expressed in % of injected dose/mmole of CO{sub 2} after correction of endogenous production of CO{sub 2}. In conclusion, carbon 14 urea breath test is a reliable noninvasive test for detection and follow-up of gastritis caused by a widespread microorganism. Also, the precision of both tests, {sup 14} C-UBT and {sup 13} C-UBT, are compared simultaneously in 84 adults patients. The results were expressed as % of administered dose expired in 30 minutes. A better precision is observed with the {sup 13} C-UBT

  9. Diagnosis of Helicobacter pylori infection; Culture, microscopy of biopsy smears, and the rapid urease test compared with the sup 14 C-urea breath test. Diagnostikk av Helicobacter pylori-infeksjon; Urease hurtigtest, mikroskopi av utstryk, og dyrking av ventrikkelbiopsi sammenlignet med sup 14 C-urea-pusteproeven

    Energy Technology Data Exchange (ETDEWEB)

    Nysaeter, G; Berstad, K; Weberg, R; Berstad, A; Hardardottir, H [Haukeland Hospital, Bergen (Norway)

    1992-08-01

    By employing the {sup 14}C-urea breath test as the reference methods the authors determined the specificity and sensitivity of three bioptic methods for diagnosis of Helicobacter pylori infection in 103 subjects. All biopsy specimens were obtained from the gastric antrum. For culture the specificity was 100%. Its applicability was reduced, however, by a low sensitivity (73.8%) and a delay of several days before the final result was available. Microscopy of Loeffler-stained biopsy smears yielded a specificity of 100% and a sensitivity of 92.9%, but the method was regarded time-consuming. The rapid urease test yielded a specificity of 98.4% and a sensitivity of 85.7%. Being quick, simple and inexpensive, the rapid urease test is well suited for routine use in gastroscopy. 17 refs., 4 tabs.

  10. Breath tests sustainability in hospital settings: cost analysis and reimbursement in the Italian National Health System.

    Science.gov (United States)

    Volpe, M; Scaldaferri, F; Ojetti, V; Poscia, A

    2013-01-01

    The high demand of Breath Tests (BT) in many gastroenterological conditions in time of limited resources for health care systems, generates increased interest in cost analysis from the point of view of the delivery of services to better understand how use the money to generate value. This study aims to measure the cost of C13 Urea and other most utilized breath tests in order to describe key aspects of costs and reimbursements looking at the economic sustainability for the hospital. A hospital based cost-analysis of the main breath tests commonly delivery in an ambulatory setting is performed. Mean salary for professional nurses and gastroenterologists, drugs/preparation used and disposable materials, purchase and depreciation of the instrument and the testing time was used to estimate the cost, while reimbursements are based on the 2013 Italian National Health System ambulatory pricelist. Variables that could influence the model are considered in the sensitivity analyses. The mean cost for C13--Urea, Lactulose and Lactose BT are, respectively, Euros 30,59; 45,20 and 30,29. National reimbursement often doesn't cover the cost of the analysis, especially considering the scenario with lower number of exam. On the contrary, in high performance scenario all the reimbursement could cover the cost, except for the C13 Urea BT that is high influenced by the drugs cost. However, consideration about the difference between Italian Regional Health System ambulatory pricelist are done. Our analysis shows that while national reimbursement rates cover the costs of H2 breath testing, they do not cover sufficiently C13 BT, particularly urea breath test. The real economic strength of these non invasive tests should be considered in the overall organization of inpatient and outpatient clinic, accounting for complete diagnostic pathway for each gastrointestinal disease.

  11. Accuracy of a rapid 10-minute carbon-14 urea breath test for the diagnosis of Helicobacter pylori-associated peptic ulcer disease

    Energy Technology Data Exchange (ETDEWEB)

    Chiahung, Kao [Taichung Veterans General Hospital (Taiwan, Province of China). Dept. of Nuclear Medicine; Shyhjen, Wang [Taichung Veterans General Hospital (Taiwan, Province of China). Dept. of Nuclear Medicine; Chungyuan, Hsu [Taichung Veterans General Hospital (Taiwan, Province of China). Dept. of Nuclear Medicine; Wanyu, Lin [Taichung Veterans General Hospital (Taiwan, Province of China). Dept. of Nuclear Medicine; Chihkua, Huang [Taichung Veterans General Hospital (Taiwan, Province of China). Dept. of Gastroenterology; Granhum, Chen [Taichung Veterans General Hospital (Taiwan, Province of China). Dept. of Gastroenterology

    1993-08-01

    Urease in the human gastric mucosa is a marker for infection with Helicobacter pylori (HP), an organism which is associated with peptic ulcer disease. To detect gastric urease, we examined 184 patients (144 males, 40 females; mean age: 49.8[+-]15.6 years) with suspected peptic ulcer disease. Fasting patients were given orally 5 [mu]Ci of carbon-14 labelled urea. For each patient only one breath sample was collected in hyamine at 10 min. The amount of [sup 14]C collected at 10 min was expressed as follows: (DPM/mmol CO[sub 2] collected)/(DPM administered)x100xbody weight (kg). The presence of HP colonization was determined by examination of multiple endoscopic prepyloric antral biopsy specimens subjected to culture or a rapid urease test. For the purpose of this study, HP-positive patients were defined as those with characteristic bacteria as indicated by a positive result of either the culture or the rapid urease test; HP-negative patients were defined as those with negative findings on both the culture and the rapid urease test. Of the 184 cases, 99 (53.8%) were positive for HP infection, and 85 (46.2%), negative. The sensitivity and specificity of the rapid 10 min [sup 14]C-urea breath test for the diagnosis of HP-associated peptic ulcer disease were evaluated by a receiver operating characteristic (ROC) curve with a variable cut-off value from 1.5 to 4.5. When a cut-off value of 1.5 was selected, the sensitivity was 100% and the specificity, 83.5%; when a cut-off value of 4.5 was selected, the sensitivity was 54.5% and the specificity, 97.6%. (orig.)

  12. Accuracy of a rapid 10-minute carbon-14 urea breath test for the diagnosis of Helicobacter pylori-associated peptic ulcer disease

    International Nuclear Information System (INIS)

    Kao Chiahung; Wang Shyhjen; Hsu Chungyuan; Lin Wanyu; Huang Chihkua; Chen Granhum

    1993-01-01

    Urease in the human gastric mucosa is a marker for infection with Helicobacter pylori (HP), an organism which is associated with peptic ulcer disease. To detect gastric urease, we examined 184 patients (144 males, 40 females; mean age: 49.8±15.6 years) with suspected peptic ulcer disease. Fasting patients were given orally 5 μCi of carbon-14 labelled urea. For each patient only one breath sample was collected in hyamine at 10 min. The amount of 14 C collected at 10 min was expressed as follows: [(DPM/mmol CO 2 collected)/(DPM administered)]x100xbody weight (kg). The presence of HP colonization was determined by examination of multiple endoscopic prepyloric antral biopsy specimens subjected to culture or a rapid urease test. For the purpose of this study, HP-positive patients were defined as those with characteristic bacteria as indicated by a positive result of either the culture or the rapid urease test; HP-negative patients were defined as those with negative findings on both the culture and the rapid urease test. Of the 184 cases, 99 (53.8%) were positive for HP infection, and 85 (46.2%), negative. The sensitivity and specificity of the rapid 10 min 14 C-urea breath test for the diagnosis of HP-associated peptic ulcer disease were evaluated by a receiver operating characteristic (ROC) curve with a variable cut-off value from 1.5 to 4.5. When a cut-off value of 1.5 was selected, the sensitivity was 100% and the specificity, 83.5%; when a cut-off value of 4.5 was selected, the sensitivity was 54.5% and the specificity, 97.6%. (orig.)

  13. Almagate interference in breath test results for the diagnosis of Helicobacter pylori infection

    Directory of Open Access Journals (Sweden)

    Carles Pons

    2014-08-01

    Full Text Available Background: Infection by Helicobacter pylori is common and affects both genders at any age. The 13C-urea breath test is a widely used test for the diagnosis of this infection. However, multiple drugs used for the treatment of Helicobacter pylori infection symptoms have interactions with this breath test that generate false negative results. This observational study was to assess the potential interaction between almagate and the breath test. Methods: Thirty subjects on almagate therapy who underwent a breath test were included. If the result was negative, almagate was withdrawn for a month and the breath test was then repeated. Results: In general, 51.9 % of assessed subjects had a negative result after the first test, and 100 % of these also had a negative result after the second test. Conclusions: It was concluded that the use of almagate does not interfere in breath test results. These results provide a drug therapy option for the treatment of symptoms associated with Helicobacter pylori infection during the diagnostic process.

  14. [*C]octanoic acid breath test to measure gastric emptying rate of solids.

    Science.gov (United States)

    Maes, B D; Ghoos, Y F; Rutgeerts, P J; Hiele, M I; Geypens, B; Vantrappen, G

    1994-12-01

    We have developed a breath test to measure solid gastric emptying using a standardized scrambled egg test meal (250 kcal) labeled with [14C]octanoic acid or [13C]octanoic acid. In vitro incubation studies showed that octanoic acid is a reliable marker of the solid phase. The breath test was validated in 36 subjects by simultaneous radioscintigraphic and breath test measurements. Nine healthy volunteers were studied after intravenous administration of 200 mg erythromycin and peroral administration of 30 mg propantheline, respectively. Erythromycin significantly enhanced gastric emptying, while propantheline significantly reduced gastric emptying rates. We conclude that the [*C]octanoic breath test is a promising and reliable test for measuring the gastric emptying rate of solids.

  15. Comparison of three stool antigen assays with the 13C- urea breath test for the primary diagnosis of Helicobacter pylori infection and monitoring treatment outcome.

    LENUS (Irish Health Repository)

    Hooton, Carmel

    2012-02-03

    BACKGROUND: The urea breath test (UBT) is the gold-standard non-invasive test for the detection of Helicobacter pylori infection, however, the lack of availability of the UBT due to the high cost of the test, and in particular the need for expensive analytical instrumentation, limits the usefulness of this method. Stool antigen assays may offer an alternative non-invasive method for the diagnosis of infection. OBJECTIVE: To compare the accuracy of three stool antigen assays (HpSA, IDEIA HpStAR, and ImmunoCard STAT) against the UBT for the primary diagnosis of H. pylori infection and for monitoring treatment outcome. METHODS: A total of 102 patients attending two gastroenterology day-case clinics for the investigation of dyspepsia were included. Each patient provided breath and stool samples for analysis. Patients who tested positive for H. pylori by the validated UBT were prescribed triple therapy and invited to return for repeat breath and stool sample analysis 6 weeks post-treatment. RESULTS: Of the 102 patients tested, 48 were diagnosed with H. pylori infection by the UBT. The HpSA assay interpreted 38 of these as positive (79% sensitive). Of the 54 UBT-negative patients the HpSA assay interpreted all 54 as negative (100% specific). The IDEIA HpStAR assay correctly identified 44 patients as positive (92% sensitive) and 50 as negative (92.5% specific). The ImmunoCard STAT assay interpreted 38 patients as positive (79% sensitive) and 52 as negative (96.3% specific). CONCLUSION: The findings indicate that the IDEIA HpStAR stool antigen kit is the most accurate assay of the three assays evaluated, and possibly represents a viable alternative to the UBT for the primary diagnosis of H. pylori infection and for monitoring treatment outcome.

  16. Methodology and application of 13C breath test in gastroenterology practice

    International Nuclear Information System (INIS)

    Yan Weili; Jiang Yibin

    2002-01-01

    13 C breath test has been widely used in research of nutrition, pharmacology and gastroenterology for its properties such as safety, non-invasion and so on. The author describes the principle, methodology of 13 C breath test and its application in detection to Helico-bacteria pylori infection in stomach and small bowl bacterial overgrowth, measurement of gastric emptying, pancreatic exocrine function and liver function with various substrates

  17. Prevalence and risk factors of helicobacter pylori in Turkey: a nationally-representative, cross-sectional, screening with the 13C-Urea breath test

    Science.gov (United States)

    2013-01-01

    Background Helicobacter pylori is an important global pathogen infecting approximately 50% of the world’s population. This study was undertaken in order to estimate the prevalence rate of Helicobacter pylori infections among adults living in Turkey and to investigate the associated risk factors. Method This study was a nationally representative cross sectional survey, using weighted multistage stratified cluster sampling. All individuals aged ≥18 years in the selected households were invited to participate in the survey. Ninety two percent (n = 2382) of the households in 55 cities participated; 4622 individuals from these households were tested with the 13C-Urea breath test. Helicobacter pylori prevalence and associated factors were analysed by the t test, chi square and multiple logistic regression with SPSS11.0. Results The weighted overall prevalence was 82.5% (95% CI: 81.0-84.2) and was higher in men. It was lowest in the South which has the major fruit growing areas of the country. The factors included in the final model were sex, age, education, marital status, type of insurance (social security), residential region, alcohol use, smoking, drinking water source. While education was the only significant factor for women, residential region, housing tenure, smoking and alcohol use were significant for men in models by sex. Conclusion In Turkey, Helicobacter pylori prevalence was found to be very high. Individuals who were women, elderly adults, single, had a high educational level, were living in the fruit growing region, had social security from Emekli Sandigi, were drinking bottled water, non smokers and regular alcohol consumers, were under less risk of Helicobacter pylori infection than others. PMID:24359515

  18. DIAGNOSTIC ACCURACY OF UREA BREATH TEST FOR HELICOBACTER PYLORI INFECTION IN CHILDREN WITH DYSPEPSIA IN COMPARISON TO HISTOPATHOLOGY

    Directory of Open Access Journals (Sweden)

    Naser HONAR

    Full Text Available ABSTRACT Background - Helicobacter pylori infection is the gram negative bacillus with the close association with chronic antral gastritis. Objective - In this study, we evaluate the accuracy of urea breath test (UBT with carbon isotope 13 in comparison with histopathology of gastric antrum for detection of H. pylori infection in children with dyspepsia. Methods - This cross-sectional study was performed at specialized laboratory of Shiraz Gastroenterohepatology Research Center and Nemazee Hospital, Iran, during a 12-months period. This study investigated the sensitivity, specificity, and positive and negative predictive values of UBT in comparison with biopsy-based tests. We included a consecutive selection of 60 children who fulfilled Rome III criteria for dyspepsia. All children were referred for performing UBT with carbon isotope 13 (C13 as well as endoscopy. Biopsies were taken from antrum of stomach and duodenum. The pathologic diagnosis was considered as the standard test. Results - The mean age of the participants was 10.1±2.6 (range 7-17 years. From our total 60 patients, 28 (46.7% had positive UBT results and 32 (53.3% had negative UBT results. Pathologic report of 16 (57.1% out of 28 patients who had positive UBT were positive for H. pylori and 12 (42.9% ones were negative. Sensitivity and specificity of C13-UBT for detection of H. pylori infection were 76.2% and 69.2% respectively. Conclusion - Sensitivity and specificity of C13-UBT for detection of H. pylori infection were 76.2% and 69.2% respectively. Another multicenter study from our country is recommended.

  19. Follow-up of coeliac disease with the novel one-hour 13C-sorbitol breath test versus the H2-sorbitol breath test.

    Science.gov (United States)

    Tveito, Kari; Hetta, Anne Kristine; Askedal, Mia; Brunborg, Cathrine; Sandvik, Leiv; Løberg, Else Marit; Skar, Viggo

    2011-07-01

    We recently developed a (13)C-sorbitol breath test ((13)C-SBT) as an alternative to the H(2)-sorbitol breath test (H(2)-SBT) for coeliac disease. In this study we compared the diagnostic properties of the H(2)-SBT and the (13)C-SBT in follow-up of coeliac disease. Twenty-seven coeliac patients on a gluten-free diet (GFD) performed the breath tests. All had been tested before treatment in the initial study of the (13)C-SBT, in which 39 untreated coeliac patients, 40 patient controls, and 26 healthy volunteers participated. Five gram sorbitol and 100 mg (13)C-sorbitol were dissolved in 250 ml tap water and given orally. H(2), CH(4) and (13)CO(2) were measured in end-expiratory breath samples every 30 min for 4 h. Increased H(2) concentration ≥20 ppm from basal values was used as cut-off for the H(2)-SBT. Sixty minutes values were used as diagnostic index in the (13)C-SBT. (13)CO(2) levels at 60 min increased in 20/26 treated coeliac patients (77%) after GFD, but were significantly lower than in control groups. Out of 20 patients who had a positive H(2)-SBT before GFD, 12 had a negative H(2)-SBT after GFD. Peak H(2) concentrations were not correlated with (13)C-SBT results. The study confirms the sensitivity of a one-hour (13)C-SBT for small intestinal malabsorption. The (13)C-SBT has superior diagnostic properties compared with the H(2)-SBT in follow-up of coeliac disease.

  20. Interpretation of non-invasive breath tests using 13C-labeled substrates - a preliminary report with 13C-methacetin

    Directory of Open Access Journals (Sweden)

    Lock JF

    2009-12-01

    Full Text Available Abstract Non-invasive breath tests can serve as valuable diagnostic tools in medicine as they can determine particular enzymatic and metabolic functions in vivo. However, methodological pitfalls have limited the actual clinical application of those tests till today. A major challenge of non-invasive breath tests has remained the provision of individually reliable test results. To overcome these limitations, a better understanding of breath kinetics during non-invasive breaths tests is essential. This analysis compares the breath recovery of a 13C-methacetin breath test with the actual serum kinetics of the substrate. It is shown, that breath and serum kinetics of the same test are significantly different over a period of 60 minutes. The recovery of the tracer 13CO2 in breath seems to be significantly delayed due to intermediate storage in the bicarbonate pool. This has to be taken into account for the application of non-invasive breath test protocols. Otherwise, breath tests might display bicarbonate kinetics despite the metabolic capacity of the particular target enzyme.

  1. Clinical application of four plasma tumor markers and 13C-urea test in diagnosis of patients with gastric carcinoma

    International Nuclear Information System (INIS)

    Pu Weigang; Tan Jifu; Zhu Jianhua; Yang Yongqing

    2010-01-01

    Objective: To investigate clinical value of plasma gastrin, leptin, carbohydrate antigen 125 (CA125), carbohydrate antigen 72-4 (CA72-4) and 13 C-urea breath test ( 13 C-UBT) in diagnosis of patients with gastric carcinoma. Methods: Radioimmunoassay and enzyme immunosorbent assay were used to determine the plasma gastrin, leptin, CA125 and CA72-4 levels, and helicobacter pylori (HP) infection rate was determined by 13 C-UBT. Compared all the determined results from 126 patients with gastric carcinoma (including 32 cases I-II stage gastric carcinoma, 57 cases III stage gastric carcinoma and 37 cases IV stage gastric carcinoma) and 60 normal controls. Results: The plasma gastrin, CA125 and CA72-4 levels in 126 patients with gastric carcinoma were significantly higher (t=3.125, t=3.159, t=3.788, P 13 C-UBT played a considerable role for diagnosis and therapy. (authors)

  2. Assessment of the (/sup 14/C) aminopyrine breath test in liver disease

    Energy Technology Data Exchange (ETDEWEB)

    Galizzi, J; Long, R G; Billing, B H; Sherlock, S [Royal Free Hospital, London (UK)

    1978-01-01

    Different methods of performing the (/sup 14/C) aminopyrine breath test have been assessed. A tracer dose of 2 ..mu..Ci without a loading dose and with a single breath collection at two hours was the method selected, since it gave the best discrimination between patients with hepatocellular diseases and normal subjects (5.2 +- 0.2%, mean - SEM). Reduced values occurred in patients with chronic active hepatitis (with and without cirrhosis) (1.5 +- 0.2%), alcoholic cirrhosis (1.7 +- 0.4%) and hepatitis (2.5 +- 0.3%), and late primary biliary cirrhosis suggesting defective microsomal function with respect to demethylation. Normal results were common in early primary biliary cirrhosis. Two weeks of prednisolone therapy caused some improvement in the breath test in nine of ten patients with chronic active hepatitis. It is concluded that the (/sup 14/C) aminopyrine breath test is a simple test for detecting hepatocellular dysfunction, but has no obvious diagnostic advantage over the determination of serum aspartate transaminase and two hour post-prandial bile-acids.

  3. Quantification of Helicobacter pylori infection in gastritis and ulcer disease using a simple and rapid carbon-14-urea breath test

    International Nuclear Information System (INIS)

    Debongnie, J.C.; Pauwels, S.; Raat, A.; de Meeus, Y.; Haot, J.; Mainguet, P.

    1991-01-01

    Gastric urease was studied isotopically in 230 patients with biopsy-proven normal mucosa or chronic gastritis, including 59 patients with ulcer disease. Carbon-14-urea was given in 25 ml of water without substrate carrier or nutrient-dense meal, and breath samples were collected over a 60-min period. The amount of 14CO2 excreted at 10 min was independent of the rate of gastric emptying and was not quantitatively influenced by the buccal urease activity. The 10-min 14CO2 values discriminated well between Helicobacter pylori positive and negative patients (94% sensitivity, 89% specificity) and correlated with the number of organisms assessed by histology. The test was a good predictor of chronic gastritis (95% sensitivity and 96% specificity), and a quantitative relationship was observed between 14CO2 values and the severity and activity of the gastritis. In H. pylori positive patients, breath 14CO2 was found to be similar in patients with and without ulcer disease, suggesting that the number of bacteria is not a determining factor for the onset of ulceration

  4. Quantification of Helicobacter pylori infection in gastritis and ulcer disease using a simple and rapid carbon-14-urea breath test

    Energy Technology Data Exchange (ETDEWEB)

    Debongnie, J.C.; Pauwels, S.; Raat, A.; de Meeus, Y.; Haot, J.; Mainguet, P. (Department of Nuclear Medicine, University of Louvain Medical School, Brussels (Belgium))

    1991-06-01

    Gastric urease was studied isotopically in 230 patients with biopsy-proven normal mucosa or chronic gastritis, including 59 patients with ulcer disease. Carbon-14-urea was given in 25 ml of water without substrate carrier or nutrient-dense meal, and breath samples were collected over a 60-min period. The amount of 14CO2 excreted at 10 min was independent of the rate of gastric emptying and was not quantitatively influenced by the buccal urease activity. The 10-min 14CO2 values discriminated well between Helicobacter pylori positive and negative patients (94% sensitivity, 89% specificity) and correlated with the number of organisms assessed by histology. The test was a good predictor of chronic gastritis (95% sensitivity and 96% specificity), and a quantitative relationship was observed between 14CO2 values and the severity and activity of the gastritis. In H. pylori positive patients, breath 14CO2 was found to be similar in patients with and without ulcer disease, suggesting that the number of bacteria is not a determining factor for the onset of ulceration.

  5. Automated 13CO2 analyzing system for the 13C breath test

    International Nuclear Information System (INIS)

    Suehiro, Makiko; Kuroda, Akira; Maeda, Masahiro; Hinaga, Kou; Watanabe, Hiroyuki.

    1987-01-01

    An automated 13 CO 2 analyzing system for the 13 C breath test was designed, built and evaluated. The system, which was designed to be controlled by a micro-computer, includes CO 2 purification, 13 CO 2 abundance measurement, data processing and data filing. This article gives the description of the whole system with flow charts. This system has proved to work well and it has become feasible to dispose of 5 to 6 CO 2 samples per hour. With such a system, the 13 C breath test will be carried out much more easily and will obtain much greater popularity. (author)

  6. Contamination by Helicobacter pylori measured by the 13C-Urea-Breath-Test and nutritional status of children with chronic diarrhoea syndrome in Havana City

    International Nuclear Information System (INIS)

    Hernandez-Triana, M.H.; Cabrera, A.; Sanchez, M. A.; Herrera, X.; Pawong, M.; Moreno, R.; Reyes, D.; Serrano, G.; Diaz, M.E.

    2002-01-01

    Diarrhoea morbidity shows a slow increasing tendency during the last 10 years in Cuba. In young children the compromise of the gastric acid barrier after a chronic infection with Helicobacter pylori (Hp) is discussed in pathogenic relation to gastritis, duodenal ulcer, chronic diarrhoea, short stature, malabsorption of the B-complex vitamins and malnutrition. The Hp contamination level of the population of the developing world is estimated to be considerably high. Endoscopic studies carried out in Cuban subjects with upper gastrointestinal symptoms show contamination values of 60 to 100%. The current treatment of chronic diarrhoea does not include the elimination of Hp. Cuban children with upper gastrointestinal symptoms show contamination values of more than 60%. There are not available data on the contamination level in apparently healthy Cuban children or those with chronic diarrhoea. In March-April 2000 the prevalence of Hp infection measured in serum by chromatographic immunoassay for detection of Hp IgG antibodies was found to be 94 % in 20 infants and young children with persistent chronic diarrhoea and 100% in 11 apparently healthy children in Havana City. Children with diarrhoea showed a more evident affection of their nutritional status and a higher percentage of positive personal or familiar history of parasitism, giardiasis, gastritis, ulcer, stomatitis and glositis. The validity of the immunological tests in infants is discussed from the point of view of the antibody transference with breast milk. In a sample of 16 different children studied by the 13C-Urea-Breath-Test the contamination level was 50% of the children not affected by diarrhoea and only one of the 6 children with diarrhoea showed positive values

  7. Predictive value of 14CO2 breath tests for clinical use of 13CO2 breath tests

    International Nuclear Information System (INIS)

    Glaubitt, D.M.H.

    1975-01-01

    The knowledge of the efficiency of 14 CO 2 breath tests makes possible the comparison of the efficiency of analogous tests using the stable isotope 13 C. 14 CO 2 exhalation studies render overall information. After parenteral administration of a 14 C labeled substrate, 14 CO 2 breath tests permit insight into the metabolism of the 14 C substrate and the associated intermediary metabolism. If the 14 C substrate is given orally or by intraduodenal instillation, 14 CO 2 breath tests supply information not only about gastrointenstinal absorption and digestion but also about the intermediary metabolism yielding 14 CO 2 , after the administered substrate or its degradation products have been absorbed in the gastrointestinal tract. The fraction of 14 CO 2 arising from absorption, digestion and intermediary metabolism can be estimated only by additional methods. 14 CO 2 breath tests are unable to delineate single metabolic reactions involved in the formation of carbon dioxide. Under these considerations the clinical application of 14 CO 2 breath tests may provide diagnostically useful results, especially in internal medicine and surgery. The tests are suitable for intraindividual assessment of the course of a disease and of therapeutic effects. They may be important in the research of the metabolism of 14 C labeled substrates

  8. Limiting the testing of urea: Urea along with every plasma creatinine test?

    Science.gov (United States)

    Zhang, Gao-Ming; Guo, Xu-Xiao; Zhang, Guo-Ming

    2017-09-01

    We found that it is not necessary to simultaneously detect both creatinine (CREA) and urea until the concentration of CREA is lower than the certain level. To reduce urea testing, we suggest measuring urea only when CREA or estimated glomerular filtration rate (eGFR) exceeds a predetermined limit. CREA and urea data were analyzed consisting of almost all of people age above 65 years old check-up (n=95441) in Shuyang countryside, and inpatients (n=101631), outpatients (n=18474) and Routine Health Check-up (n=20509) in Shuyang People's Hospital. The proportions of elevated urea were derived. The data used in this study was generated from people more than 13 years old in both outpatients and inpatients. When the limits for initiating urea testing were used at 85 μmol/L CREA and 120 mL/min/1.73 m 2 eGFR, the percentage of unnecessary urea test are 94.5% and 64.7% (elderly health check-up), 67.9% and 84.5% (outpatients), 88.5% and 73.2% (inpatients), 92.2% and 81.7% (routine health check-up). The missing rate of urea are 1%, 2.5%, 4.6% and 9.2%, 0.1%, 0.4%, 0.9% and 1.8%, 0.4%, 0.8%, 1.4%, and 2.5%, 0.05%, 0.1%, 1.1%, and 0.8% of ureas exceeding 9.28 mmol/L and 8.3 mmol/L in above each group, respectively. If the CREA≤85 μmol/L or eGFR≥90 mL/min/1.73 m 2 , there is 97.5% urea urea missed is 2.5%. We suggest that the initiating urea testing should be based on the upper limit of Reference Intervals serum CREA of females or a 120 mL/min/1.73 m 2 eGFR limit. Conservatively, the urea testing would be reduced by 65% at least. © 2017 Wiley Periodicals, Inc.

  9. Medical Diagnostic Breath Analysis by Cavity Ring Down Spectroscopy

    Science.gov (United States)

    Guss, Joseph S.; Metsälä, Markus; Halonen, Lauri

    2009-06-01

    Certain medical conditions give rise to the presence of chemicals in the bloodstream. These chemicals - known as biomarkers - may also be present in low concentrations in human breath. Cavity ring down spectroscopy possesses the requisite selectivity and sensitivity to detect such biomarkers in the congested spectrum of a breath sample. The ulcer-causing bacterium, Helicobacter pylori, is a prolific producer of the enzyme urease, which catalyses the breakdown of urea ((NH_2)_2CO) in the stomach as follows: (NH_2)_2CO + H_2O ⟶ CO_2 + 2NH_3 Currently, breath tests seeking altered carbon-isotope ratios in exhaled CO_2 after the ingestion of ^{13}C- or ^{14}C-labeled urea are used to diagnose H. pylori infection. We present recent results from an ongoing collaboration with Tampere Area University Hospital. The study involves 100 patients (both infected and uninfected) and concerns the possible correlation between the bacterial infection and breath ammonia. D. Y. Graham, P. D. Klein, D. J. Evans, Jr, D. G. Evans, L. C. Alpert, A. R. Opekun, T. W. Boutton, Lancet 1(8543), 1174-7 March 1987.

  10. Determination of urea 13C in urea 13C mixed powder by HPLC

    International Nuclear Information System (INIS)

    Zhong Jianguo; Song Tianqi

    2006-01-01

    A HPLC method is developed for determination of Urea 13 C in Urea 13 C Mixed Powder. A Alltech Econosphere NH2 column (250 mm x 4.6 mm, 5 μm)is used as stationary phrase, a mixture of V(acetonitrile): V(methanol): V(water) = 900 : 100: 10 is used as mobile phase and the flow rate is l mL·min -1 , UV detection wavelength is performed at 200 nm. The calibration curve shows good linearity in the range of 0.2-1.0 g·L -1 of Urea 13 C, y=2.548 x 10 6 x + 4.005 x 10 4 , r=0.9999, and the averaged recovery is 100.6%. The method is simple and accurate, and can be used for the quality control of Urea 13C Mixed Powder. (authors)

  11. Urea recycling from the renal pelvis in sheep: A study with [14C]urea

    International Nuclear Information System (INIS)

    Cirio, A.; Boivin, R.

    1990-01-01

    To test the hypothesis that urea can be recycled from the renal pelvis, [14C]urea diluted in native urine (1 microCi/ml) was perfused (0.5 ml/min) into one of the pelvises of sheep fed either normal (NP) or low (LP)-protein diets. Blood samples were obtained from the ipsilateral renal vein and from the carotid artery throughout the perfusions. 14C activity determinations in urine and plasma demonstrated a flux of [14C]urea from the pelvis to renal vein blood (40,000 in NP and 130,000 disintegrations/min in LP sheep, P less than 0.01). The corresponding flux of native urea was only 1.5 times higher in NP than in LP sheep (6.8 +/- 1.1 vs. 4.7 +/- 2.9 mumol/min, not significant) despite their 8 times higher urinary concentration of urea. The fraction of filtered urea that was reabsorbed in the pelvis was larger in LP sheep (7.5 +/- 3.7 vs. 1.9 +/- 0.7% in NP sheep, P less than 0.05). A fraction of urea is thus actually recycled from the renal pelvis in sheep, and this pelvic retention is enhanced in LP animals. The importance of this phenomenon in the nitrogen economy is discussed

  12. Breath Ketone Testing: A New Biomarker for Diagnosis and Therapeutic Monitoring of Diabetic Ketosis

    Directory of Open Access Journals (Sweden)

    Yue Qiao

    2014-01-01

    Full Text Available Background. Acetone, β-hydroxybutyric acid, and acetoacetic acid are three types of ketone body that may be found in the breath, blood, and urine. Detecting altered concentrations of ketones in the breath, blood, and urine is crucial for the diagnosis and treatment of diabetic ketosis. The aim of this study was to evaluate the advantages of different detection methods for ketones, and to establish whether detection of the concentration of ketones in the breath is an effective and practical technique. Methods. We measured the concentrations of acetone in the breath using gas chromatography-mass spectrometry and β-hydroxybutyrate in fingertip blood collected from 99 patients with diabetes assigned to groups 1 (−, 2 (±, 3 (+, 4 (++, or 5 (+++ according to urinary ketone concentrations. Results. There were strong relationships between fasting blood glucose, age, and diabetic ketosis. Exhaled acetone concentration significantly correlated with concentrations of fasting blood glucose, ketones in the blood and urine, LDL-C, creatinine, and blood urea nitrogen. Conclusions. Breath testing for ketones has a high sensitivity and specificity and appears to be a noninvasive, convenient, and repeatable method for the diagnosis and therapeutic monitoring of diabetic ketosis.

  13. 13C mixed triglyceride breath test: a noninvasive method to assess lipase activity in children.

    Science.gov (United States)

    van Dijk-van Aalst, K; Van Den Driessche, M; van Der Schoor, S; Schiffelers, S; van't Westeinde, T; Ghoos, Y; Veereman-Wauters, G

    2001-05-01

    Results from the 13C mixed triglyceride (MTG) breath test correlate with duodenal lipase activity in adults. This noninvasive test is a potential screening and diagnostic tool for children with fat malabsorption. The aim of this study was to adapt the methodology of the MTG breath test to study test meals and sampling methods and to define normal values for healthy children of all age groups; premature and full-term infants have similar pancreatic lipase deficiencies. After parental consent was obtained, 12 premature infants ( 2 kg), 12 full-term infants (1-6 months old), 20 children (3-10 years old), and 20 teenagers (11-17 years old) were tested. All children were thriving well, had no gastrointestinal or respiratory problems, and had not received any medication that contained natural 13C. For the premature and full-term infants, a formula was prepared that had a low and stable natural 13C content mixed with 100 mg 13C-labeled MTG (1,3-distearyl, 2-[13C-carboxyl] octanoyl glycerol) and 1 g polyethylene-glycol 3350. The best accepted test meal for children over 3 years old was a slice of white bread with 5 g butter and 15 g chocolate paste, mixed with 250 mg 13C-labeled MTG, and a glass of 100 mL whole-fat milk. Children over 3 years old were able to blow through a straw in a vacutainer for collecting the breath samples. In children under 3 years old, expired air was collected by aspirating breath via a nasal prong. Carbon dioxide production was calculated according to weight, age, and sex. For healthy pediatric control participants, the mean values for cumulative excretion of 13CO2 as a percentage of the administered dose after 6 hours were 23.9 +/- 5.2% in premature infants, 31.9 +/- 7.7% in full-term infants, 32.5 +/- 5.3% in children, and 28.0 +/- 5.4% in teenagers. The mean value for healthy adults is 35.6% with a lower reference limit of 22.8%. Age-specific test meals and breath-sampling techniques for the MTG breath test were defined. The mean values for

  14. Additional Value of CH4 Measurement in a Combined 13C/H2 Lactose Malabsorption Breath Test: A Retrospective Analysis

    Science.gov (United States)

    Houben, Els; De Preter, Vicky; Billen, Jaak; Van Ranst, Marc; Verbeke, Kristin

    2015-01-01

    The lactose hydrogen breath test is a commonly used, non-invasive method for the detection of lactose malabsorption and is based on an abnormal increase in breath hydrogen (H2) excretion after an oral dose of lactose. We use a combined 13C/H2 lactose breath test that measures breath 13CO2 as a measure of lactose digestion in addition to H2 and that has a better sensitivity and specificity than the standard test. The present retrospective study evaluated the results of 1051 13C/H2 lactose breath tests to assess the impact on the diagnostic accuracy of measuring breath CH4 in addition to H2 and 13CO2. Based on the 13C/H2 breath test, 314 patients were diagnosed with lactase deficiency, 138 with lactose malabsorption or small bowel bacterial overgrowth (SIBO), and 599 with normal lactose digestion. Additional measurement of CH4 further improved the accuracy of the test as 16% subjects with normal lactose digestion and no H2-excretion were found to excrete CH4. These subjects should have been classified as subjects with lactose malabsorption or SIBO. In conclusion, measuring CH4-concentrations has an added value to the 13C/H2 breath test to identify methanogenic subjects with lactose malabsorption or SIBO. PMID:26371034

  15. C-13-carbohydrate breath tests : Impact of physical activity on the rate-limiting step in lactose utilization

    NARCIS (Netherlands)

    Stellaard, F; Koetse, HA; Elzinga, H; Boverhof, R; Tjoonk, R; Klimp, A; Vegter, D; Liesker, J; Vonk, RJ

    Background: (CO2)-C-13 breath tests can be used to monitor carbohydrate digestion in the small intestine. However, after ingestion of C-13-substrates, (CO2)-C-13 excretion in breath originates from two sources: a digestive/oxidative fraction, derived from the small intestine, and a fermentation

  16. Comparison of four urease-dependent tests of detecting HP infection

    International Nuclear Information System (INIS)

    Han Yuan; Huang Gang; Zhu Cuiying; Ling Liqun

    2001-01-01

    Objective: The aim of this study is to compare the four urease-dependent tests of detecting Hp infection. The authors used following method: 1) rapid urease test (RUT), 2) 14 C urea breath test ( 14 C-UBT), 3) 13 C urea breath test which is measured by with infrared spectrometry ( 13 C-UBT1), 4) 13 C urea breath test with mass spectrometry ( 13 C-UBT). Methods: 54 patients underwent RUT, 14 C-UBT, 13 C-UBT1, 13 C-UBT2 respectively. Results: Sensitivity and specificity, accurate rate, positive predictive value (PPV), negative predictive value (NPV), respectively, were as follows: RUT (82.1%, 80%, 81.5%, 91.4%, 63.2%), 14 C-UBT (97.4%, 100%, 98.1%, 100%, 93.8%), 13 C-UBT1 (100%, 93.3%, 98.1%, 97.5%, 100%), 13 C-UBT2 (100%, 86.7%, 96.3%, 95.1%, 100%), PPV of four tests are not significantly different (P>0.05). Conclusion: Four urease-dependent tests are high sensitive and accurate methods for detecting Hp infection. UBT is an ideal tool for diagnosis, screen and follow-up of Hp infection

  17. /sup 14/C-glycocholate breath test and pathological digestive transit

    Energy Technology Data Exchange (ETDEWEB)

    Talbot, J N; Coutris, G; Charpentier, G; Milhaud, G [Hopital Saint-Antoine, Paris (France)

    1982-01-01

    /sup 14/C-glycine glycocholate breath test is elegant, atraumatic and detects bacterial overgrowth in the proximal portion of small intestine. In such cases an early increase of specific radioactivity of CO/sub 2/ occurs in expired air. Ileal bile salts malabsorption can also induce such an increase in principle later. However, a modification of transit (acceleration or paresis) can shift the time of appearance of the physiological /sup 14/CO/sub 2/ peak due to colonic deconjugation of the labelled tracer, leading to a diagnostic error. Microbial overgrowth, gastroparesis, accelerated intestinal transit or malabsorption can complicate diabetes mellitus, especially in the case of diabetic neuropathy. Several of these disorder can coexist. It is possible to detect and quantify all these abnormalities in a single examination by the simultaneous use of labelled glycocholate and sup(99m)Tc DTPA. Oral administration of this mixture allows the measurement of gastric emptying half-time and the scintigraphic visualisation of labelled meal progression. Thus, the association of /sup 14/C-glycocholate breath-test and sup(99m)Tc DTPA digestive transit insures a correct interpretation in case of associated abnormalities.

  18. Application of the glycocolate 14C breath test in the stydy of rosacea

    International Nuclear Information System (INIS)

    Woscoff, A.; Wainer, S.; Gaon, D.; Pisarello de Troparevsky, M.L.; Arciprete, C.P.; Mitta, A.E.A.

    1987-01-01

    Small bowel bacterial contamination was determined in patients affected by rosacea normal or gastric hyposecretors. The Breath Test 14 C was used with glycocolate 14 C Na. The study was completed by determination of gastric acidity, Key test, Schilling test and d xilosa test with positive results. Metronidazol was administered to these patients, thus normalizing the small bowel contamination and, at the same time, improving the dermatological process. (M.E.L.) [es

  19. Experimental study on L-[1-13C] phenylalanine breath test for quantitative assessment of liver function with animal

    International Nuclear Information System (INIS)

    Yan Weili; Fudan Univ., Shanghai; Lin Xiangtong; Sun Dayu; Jiang Yibin; Sun Xu; Rong Lan; Liang Qi

    2006-01-01

    Objective: Using a small animal breath test model we designed and L-[1- 13 C] phenylalanine breath test ( 13 C-PheBT) of rats, the authors investigated its feasibility and validity and determined effective parameter of the test. Methods: Twenty male Sprague-Dawley (SD) weighting 280-290 g rats randomized into two groups acute hepatitis rats (n=10) and control rats (n=10). Hepatitis was induced by carbon tetrachloride (CCl 4 ) olive oil administration through intragastric gavage. PheBT was assisted by small mechanical ventilator improved and air samples were collected discontinuously, 20 mg/kg body weight L-[1- 13 C] phenylalanine ( 13 C-Phe) was administered intravenously. Twenty-nine breath samples were taken before and different intervals within sixty minutes after administration. 13 Cenrichment was measured by isotope ratio mass spectrometer. Results: All time phase curves of 13 C enrichment in rat breath reached a peak almost at 2 min after the intravenous administration of 13 C-Phe. The PheBT parameters, 13 C excretion rate constant (PheBT-K), of CCl 4 hepatitis rats were significantly lower than that of normal control rats [(2.45 ± 0.25) x 10 -2 min -1 vs (2.98 ± 0.19) x 10 -2 min -1 , t = 5.40, P 13 C fast phase disposition constant did not statistically differ between the two groups (t=0.58, P>0.05). PheBT-K had significant negative cor-relation with serum ALT, AKP, TBA and total bilirum TBIL (the correlation coefficient r is -0.74, -0.73, -0.82 and -0.67 respectively, P 0.05). Conclusions: It was indicated that the small animal breath test model we designed was a virtual tool to use in experimental study on breath test and PheBT-K was a sensitive index. (authors)

  20. Synthesis and quality control of {sup 13}C-enriched urea for Helicobacter pylori (HP) diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Sant Ana Filho, Carlos R.; Tavares, Claudineia R.O.; Ferreira, Andre V.; Prestes, Cleber V.; Bendassolli, Jose A., E-mail: jab@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2013-08-01

    The aim of the study was to synthesize the urea ({sup 13}CO(NH{sub 2}){sub 2}), with 99% {sup 13}C atoms, and to perform a quality analysis for the diagnosis (breath test) of Helicobacter pylori. Furthermore, the process was submitted to economic analysis. The reaction was performed in a stainless steel reactor, lined with polytetrafluoroethylene, under low pressure and temperature. The synthesis method was shown to be appropriate (2.35 g; 81.9% yield), evidenced by physico-chemical and microbiological results, according to Brazilian legislation. The production and diagnosis costs were competitive compared with national and international market values, rendering this a valuable tool in clinical medicine. (author)

  1. Small intestinal malabsorption in chronic alcoholism: a retrospective study of alcoholic patients by the ¹⁴C-D-xylose breath test.

    Science.gov (United States)

    Hope, Håvar; Skar, Viggo; Sandstad, Olav; Husebye, Einar; Medhus, Asle W

    2012-04-01

    The ¹⁴C-D-xylose breath test was used at Ullevål University Hospital in the period from 1986 TO 1995 for malabsorption testing. The objective of this retrospective study was to reveal whether patients with chronic alcoholism may have intestinal malabsorption. The consecutive ¹⁴C-D-xylose breath test database was reviewed and patients with the diagnosis of chronic alcoholism were identified. ¹⁴C-D-xylose breath test results of the alcoholic patients were compared with the results of untreated celiac patients and patient and healthy controls. In the ¹⁴C-D-xylose breath test, ¹⁴C-D-xylose was dissolved in water and given orally after overnight fast. Breath samples were taken at 30-min intervals for 210 min, and ¹⁴CO₂ : ¹²CO₂ ratios were calculated for each time point, presenting a time curve for ¹⁴C-D-xylose absorption. Urine was collected after 210 min and the fraction of the total d-xylose passed was calculated (U%). ¹⁴CO₂ in breath and ¹⁴C-D-xylose in urine were analyzed using liquid scintillation. Both breath and urine analysis revealed a pattern of malabsorption in alcoholics comparable with untreated celiac patients, with significantly reduced absorption of d-xylose compared with patient and healthy controls. Alcoholic patients have a significantly reduced ¹⁴C-D-xylose absorption, comparable with untreated celiac patients. This indicates a reduced intestinal function in chronic alcoholism.

  2. Contamination by Helicobacter pylori measured by the 13C-urea-breast-test and nutritional status of children with chronic diarrhoea syndrome in Havana city

    International Nuclear Information System (INIS)

    Cabrera, A.; Hernandez-Triana, M.; Sanchez, M.; Herrera, X.; Pawong, M.; Moreno, R.; Reyes, D.; Serrano, G.; Diaz, M.E.; Valencia, M.

    2000-01-01

    Diarrhoea morbidity shows a slow increasing tendency during the last 10 years in Cuba. In young children the compromise of the gastric acid barrier after a chronic infection with Helicobacter pylori is discussed in pathogenic relation to gastritis, duodenal ulcer chronic diarrhoea, short stature, malabsorption of the B-complex vitamins and malnutrition. The Hp contamination level of the population of the developing world is estimated to be considerably high. Endoscopic studies carried out in Cuban subjects with upper gastrointestinal symptoms show contamination values of 60 to 100%. The current treatment of chronic diarrhoea does not include the elimination of Hp. Cuban children with upper gastrointestinal symptoms show contamination values of more than 60%. There are not available data on the contamination level in apparently healthy Cuban children or those with chronic diarrhoea. In March-April 2000 the prevalence of Hp infection measured in serum by chromatographic immunoassay for detection of Hp IgG antibodies was found to be 94% in 20 infants and young children with persistent chronic diarrhoea and 100% in 11 apparently healthy children in Havana City. Children with diarrhoea showed a more evident affection of their nutritional status and a higher percentage of positive personal or familiar history of parasitism, giardiasis, gastritis, ulcer stomatitis and glositis. The validity of the immunological tests in infants is discussed from the point of view of the antibody transference with breast milk. In a sample of 16 different children studied by the 13 C-Urea-Breath-Test the contamination level was 50% of the children not affected by diarrhoea and only one of the 6 children with diarrhoea showed positive values. This research contract proposes the study of contamination with Hp in Cuban children older than 2 years of age affected by chronic diarrhoea using the 13 C-Urea Breath Test and serological tests for detection of anti-Hp IgG antibodies. Their nutritional

  3. Diagnostic Limitations of 13C-Mixed Triglyceride Breath Test in Patients after Cholecystectomy

    Directory of Open Access Journals (Sweden)

    V.I. Rusyn

    2014-09-01

    Full Text Available The results of a comprehensive examination of 136 patients after cholecystectomy are provided. High efficiency and informativeness of the 13C-mixed triglyceride breath test for determining exocrine pancreatic insufficiency at its early stages was noted in patients after cholecystectomy.

  4. Contamination by Helicobacter pylori measured by the {sup 13}C-urea-breast-test and nutritional status of children with chronic diarrhoea syndrome in Havana city

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera, A; Hernandez-Triana, M; Sanchez, M; Herrera, X; Pawong, M; Moreno, R; Reyes, D; Serrano, G; Diaz, M E [Institute of Nutrition and Food Hygiene, Department of Biochemistry and Physiology, Havana (Cuba); Valencia, M [Centro de Investigacion en Alimentacion y Desarrollo, Department of Human Nutrition, Hermosillo, Sonora (Mexico)

    2000-07-01

    Diarrhoea morbidity shows a slow increasing tendency during the last 10 years in Cuba. In young children the compromise of the gastric acid barrier after a chronic infection with Helicobacter pylori is discussed in pathogenic relation to gastritis, duodenal ulcer chronic diarrhoea, short stature, malabsorption of the B-complex vitamins and malnutrition. The Hp contamination level of the population of the developing world is estimated to be considerably high. Endoscopic studies carried out in Cuban subjects with upper gastrointestinal symptoms show contamination values of 60 to 100%. The current treatment of chronic diarrhoea does not include the elimination of Hp. Cuban children with upper gastrointestinal symptoms show contamination values of more than 60%. There are not available data on the contamination level in apparently healthy Cuban children or those with chronic diarrhoea. In March-April 2000 the prevalence of Hp infection measured in serum by chromatographic immunoassay for detection of Hp IgG antibodies was found to be 94% in 20 infants and young children with persistent chronic diarrhoea and 100% in 11 apparently healthy children in Havana City. Children with diarrhoea showed a more evident affection of their nutritional status and a higher percentage of positive personal or familiar history of parasitism, giardiasis, gastritis, ulcer stomatitis and glositis. The validity of the immunological tests in infants is discussed from the point of view of the antibody transference with breast milk. In a sample of 16 different children studied by the {sup 13}C-Urea-Breath-Test the contamination level was 50% of the children not affected by diarrhoea and only one of the 6 children with diarrhoea showed positive values. This research contract proposes the study of contamination with Hp in Cuban children older than 2 years of age affected by chronic diarrhoea using the {sup 13}C-Urea Breath Test and serological tests for detection of anti-Hp IgG antibodies. Their

  5. Preparation of 14C-labelled urea for diagnosis of helicobacter pylori infection

    International Nuclear Information System (INIS)

    Jiang Bingsheng

    2001-01-01

    The preparation of 14 C-urea from [ 14 C]-barium carbonate is reported. The results show that chemical yield can reach 80% (average of 6 runs); melt point is 132 - 136 degree C; purity is 99.65% - 99.85%. After being analyzed by IR, UV, NMR, MS, and elemental analysis, the 14 C-urea has the same molecular structure as that of standard urea. Animal trial indicates that clinical use is safe. Good stability is shown by stability testing under different luminous flux, temperature and relative humidity

  6. Validation of 13C-acetic acid breath test by measuring effects of loperamide, morphine, mosapride, and itopride on gastric emptying in mice.

    Science.gov (United States)

    Matsumoto, Kenjiro; Kimura, Hiroshi; Tashima, Kimihito; Uchida, Masayuki; Horie, Syunji

    2008-10-01

    Several methods are used to evaluate gastric motility in rodents, but they all have technical limitations. Recent technical developments enable a convenient method to evaluate gastric motility. The (13)C-acetic acid breath test in rodents is a non-invasive and repeatable method that can be used without physical restraints. The present study aimed to validate the (13)C-acetic acid breath test by measuring the effects of loperamide, morphine, mosapride, and itopride on gastric emptying in mice. Loperamide (1-10 mg/kg) and morphine (1.25-10 mg/kg) slowed gastric emptying and decreased the maximum concentration (C(max)) and area under the curve (AUC(90 min)) value in a dose-dependent manner. Mosapride (0.2-5 mg/kg) accelerated gastric emptying and increased C(max) value. Mosapride (20 mg/kg) did not accelerate gastric emptying on the (13)C-breath test. Itopride (30 mg/kg, per os) significantly accelerated gastric emptying compared with the vehicle group. In a comparison with the conventional phenol red test, there was a correlation between the C(max) value of breath test and gastric emptying (%) of phenol red tests in treatment with loperamide or mosapride. These results indicate that the (13)C-acetic acid breath test is an accurate, noninvasive, and simple method for monitoring gastric emptying in mice. This method is useful to assess the effect of drugs and gut function pharmacologically.

  7. Effect of DA-9701 on gastric emptying in a mouse model: assessment by ¹³C-octanoic acid breath test.

    Science.gov (United States)

    Lim, Chul-Hyun; Choi, Myung-Gyu; Park, Hyeyeon; Baeg, Myong Ki; Park, Jae Myung

    2013-07-21

    To evaluate the effects of DA-9701 on the gastric emptying of a solid meal using the ¹³C-octanoic acid breath test in a mouse model. Male C57BL/6 mice aged > 8 wk and with body weights of 20-25 g were used in this study. The solid test meal consisted of 200 mg of egg yolk labeled with 1.5 L/g ¹³C-octanoic acid. The mice were placed in a 130 mL chamber flushed with air at a flow speed of 200 mL/min. Breath samples were collected for 6 h. The half-emptying time and lag phase were calculated using a modified power exponential model. To assess the reproducibility of the ¹³C-octanoic acid breath test, the breath test was performed two times at intervals of one week in ten mice without drug treatment. To assess the gastrokinetic effects of DA-9701, the breath test was performed three times in another twelve mice, with a randomized crossover sequence of three drug treatments: DA-9701 3 mg/kg, erythromycin 6 mg/kg, or saline. Each breath test was performed at an interval of one week. Repeatedly measured half gastric emptying time of ten mice without drug treatment showed 0.856 of the intraclass correlation coefficient for the half gastric emptying time (P = 0.004). The mean cumulative excretion curve for the ¹³C-octanoic acid breath test showed accelerated gastric emptying after DA-9701 treatment compared with the saline control (P = 0.028). The median half gastric emptying time after the DA-9701 treatment was significantly shorter than after the saline treatment [122.4 min (109.0-137.9 min) vs 134.5 min (128.4-167.0 min), respectively; P = 0.028] and similar to that after the erythromycin treatment [123.3 min (112.9-138.2 min)]. The lag phase, which was defined as the period taken to empty 15% of a meal, was significantly shorter after the DA-9701 treatment than after the saline treatment [48.1 min (44.6-57.1 min) vs 52.6 min (49.45-57.4 min), respectively; P = 0.049]. The novel prokinetic agent DA-9701 accelerated gastric emptying, assessed with repeated

  8. Predicting outcome of paracetamol poisoning by using 14C-aminopyrine breath test

    International Nuclear Information System (INIS)

    Saunders, J.B.; Wright, N.; Lewis, K.O.

    1980-01-01

    The 14 C-aminopyrine ( 14 C-amidopyrine) breath test, carried out within 24 to 36 hours of an overdosage of paracetamol, was used to predict the extent of liver damage in 30 seriously poisoned patients. Mean 14 C0 2 excretion was 4.4% in 20 healthy control subjects; 5.5% in six patients who escaped injury; and 2.9%, 1.5%, and 0.2% in those with mild to moderate (12 patients), severe (eight patients), and fatal (four patients) liver damage respectively. This test proved to be a more reliable predictor of the extent of liver damage than plasma paracetamol concentration or half life or the results of conventional liver function tests and may enable treatment of hepatic failure to be started at an early stage. (author)

  9. Minimally invasive (13)C-breath test to examine phenylalanine metabolism in children with phenylketonuria.

    Science.gov (United States)

    Turki, Abrar; Murthy, Gayathri; Ueda, Keiko; Cheng, Barbara; Giezen, Alette; Stockler-Ipsiroglu, Sylvia; Elango, Rajavel

    2015-01-01

    Phenylketonuria (PKU) is an autosomal recessive disorder caused by deficiency of hepatic phenylalanine hydroxylase (PAH) leading to increased levels of phenylalanine in the plasma. Phenylalanine levels and phenylalanine hydroxylase (PAH) activity monitoring are currently limited to conventional blood dot testing. 1-(13)C-phenylalanine, a stable isotope can be used to examine phenylalanine metabolism, as the conversion of phenylalanine to tyrosine occurs in vivo via PAH and subsequently releases the carboxyl labeled (13)C as (13)CO2 in breath. Our objective was to examine phenylalanine metabolism in children with PKU using a minimally-invasive 1-(13)C-phenylalanine breath test ((13)C-PBT). Nine children (7 M: 2 F, mean age 12.5 ± 2.87 y) with PKU participated in the study twice: once before and once after sapropterin supplementation. Children were provided 6 mg/kg oral dose of 1-(13)C-phenylalanine and breath samples were collected at 20 min intervals for a period of 2h. Rate of CO2 production was measured at 60 min post-oral dose using indirect calorimetry. The percentage of 1-(13)C-phenylalanine exhaled as (13)CO2 was measured over a 2h period. Prior to studying children with PKU, we tested the study protocol in healthy children (n = 6; 4M: 2F, mean age 10.2 ± 2.48 y) as proof of principle. Production of a peak enrichment (Cmax) of (13)CO2 (% of dose) in all healthy children occurred at 20 min ranging from 17-29% of dose, with a subsequent return to ~5% by the end of 2h. Production of (13)CO2 from 1-(13)C-phenylalanine in all children with PKU prior to sapropterin treatment remained low. Following sapropterin supplementation for a week, production of (13)CO2 significantly increased in five children with a subsequent decline in blood phenylalanine levels, suggesting improved PAH activity. Sapropterin treatment was not effective in three children whose (13)CO2 production remained unchanged, and did not show a reduction in blood phenylalanine levels and improvement

  10. Standardization of the TRUE Test imidazolidinyl urea and diazolidinyl urea patches

    DEFF Research Database (Denmark)

    Agner, T; Andersen, Klaus Ejner; Björkner, B

    2001-01-01

    The preservatives imidazolidinyl urea (IMID, Germall 115) and diazolidinyl urea (DU, Germall II) are commonly used in cosmetic products and are well-known sensitizers. The aim of the present study was to establish the optimal patch test concentration in hydrophilic dried-in vehicle (TRUE Test...

  11. Synthesis of ¹³C-lidocaine as a probe of breath test for the evaluation of cytochrome P450 activity.

    Science.gov (United States)

    Mitome, Hidemichi; Sugiyama, Erika; Sato, Hitoshi; Akira, Kazuki

    2014-01-01

    (13)C-Labeled lidocaine, 2-di[1-(13)C]ethylamino-N-(2,6-dimethylphenyl)acetamide (1), was synthesized from [1-(13)C]acetic acid in six steps, as a probe for a breath test to evaluate in vivo cytochrome P450 activity. The measurement of (13)CO2 in breath was successfully performed following oral administration of (13)C-lidocaine 1 to mice.

  12. In vivo assessment of the mitochondrial response to caloric restriction in obese women by the 2-keto[1-C]isocaproate breath test.

    Science.gov (United States)

    Parra, Dolores; González, Alvaro; Martínez, J Alfredo; Labayen, Idoia; Díez, Nieves

    2003-04-01

    The 2-keto[1-(13)C]isocaproate breath test has been proposed as a tool to detect mitochondrial dysfunction in alcoholic liver disease. The aim of this study was to evaluate if the 2-keto[1-(13)C]isocaproate breath test could detect in vivo dynamic changes on mitochondrial activity due to caloric restriction in obese women. Fifteen obese women (body mass index [BMI] > 30 kg/m(2)) participated in the study at baseline. Ten of these women agreed to participate on a diet program to induce body weight loss. Fifteen lean women (BMI keto[1-(13)C]isocaproate breath test and the plasma insulin (before diet: P =.863; after diet: P =.879), or leptin (before diet: P =.500; after diet: P =.637). In obese women before treatment, kilograms of fat free mass (P =.108), resting energy expenditure adjusted for body composition (P =.312), and the 2-keto[1-(13)C]isocaproate breath test (P =.205) were similar in comparison to lean women. However, 2-keto[1-(13)C]isocaproate oxidation tended to increase after dieting and was significantly higher than in controls (P =.015). These data suggest that the 2-keto[1-(13)C]isocaproate breath test reflected the adaptive modifications in mitochondrial oxidation in response to caloric restriction in obese women. Copyright 2003 Elsevier, Inc. All rights reserved.

  13. 21 CFR 862.1770 - Urea nitrogen test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine...

  14. Does postprandial itopride intake affect the rate of gastric emptying? A crossover study using the continuous real time 13C breath test (BreathID system).

    Science.gov (United States)

    Nonaka, Takashi; Kessoku, Takaomi; Ogawa, Yuji; Yanagisawa, Shogo; Shiba, Tadahiko; Sahaguchi, Takashi; Atsukawa, Kazuhiro; Takahashi, Hisao; Sekino, Yusuke; Iida, Hiroshi; Hosono, Kunihiro; Endo, Hiroki; Sakamoto, Yasunari; Koide, Tomoko; Takahashi, Hirokazu; Tokoro, Chikako; Abe, Yasunobu; Maeda, Shin; Nakajima, Atsushi; Inamori, Masahiko

    2011-01-01

    The aim of this study was to determine whether oral Itopride hydrochloride (itopride) intake might have any effect on the rate of gastric emptying, using a novel non-invasive technique for measuring the rate of gastric emptying, namely, the continuous real time 13C breath test (BreathID system: Exalenz Bioscience Ltd., Israel). Eight healthy male volunteers participated in this randomized, two-way crossover study. The subjects fasted overnight and were randomly assigned to receive 50mg itopride following a test meal (200 kcal per 200mL, containing 100mg 13C acetate), or the test meal alone. Under both conditions, gastric emptying was monitored for 4 hours after administration of the test meal by the 13C-acetic acid breath test performed continually using the BreathID system. Using Oridion Research Software (beta version), the time required for emptying of 50% of the labeled meal (T 1/2), the analog to the scintigraphy lag time for 10% emptying of the labeled meal (T lag), the gastric emptying coefficient (GEC), and the regression-estimated constants (beta and kappa) were calculated. The parameters measured under the two conditions were compared using the Wilcoxon's signed-rank test. No significant differences in the calculated parameters, namely, the T 1/2, T lag, GEC, beta or kappa, were observed between the two test conditions, namely, administration of a test meal+itopride and administration of the test meal alone. The present study revealed that postprandial itopride intake had no significant influence on the rate of gastric emptying. Recently, several studies have shown that itopride may be effective in the treatment of patients with functional dyspepsia. Our results suggest that the efficacy of itopride in patients with functional dyspepsia may be based on its effect of improving functions other than the rate of gastric emptying, such as the activities at neuronal sites, brain-gut correlation, visceral hypersensitivity, gastric accommodation and distension

  15. /sup 14/C-D-galactose breath test for evaluation of liver function in patients with chronic liver disease

    Energy Technology Data Exchange (ETDEWEB)

    Caspary, W F; Schaffer, J

    1978-01-01

    D-galactose metabolism and demethylation of aminopyrine by healthy controls and patients with chronic active hepatitis (CAH) and cirrhosis (Ci), were assessed by a breath analysis technique measuring /sup 14/CO2 exhalation after oral ingestion of /sup 14/C-D-galactose or /sup 14/C-aminopyrine. Patients with CAH and Ci exhibited decreased /sup 14/CO2-exhalation rates following /sup 14/-D-galactose or /sup 14/C-aminopyrine. D-galactose oxidation capacity of the liver can be assessed by a breath analysis technique in analogy to the demethylating function for aminopyrine. The ordinary oral D-galactose tolerance test seems, however, superior in comparison to the /sup 14/C-D-galactose tolerance test, in discriminating between healthy controls and patients with chronic liver disease.

  16. Comparison of the 1-gram [14C]xylose, 10-gram lactulose-H2, and 80-gram glucose-H2 breath tests in patients with small intestine bacterial overgrowth

    International Nuclear Information System (INIS)

    King, C.E.; Toskes, P.P.

    1986-01-01

    The sensitivity of three breath tests (1-g [ 14 C]xylose, 10-g lactulose-H 2 , and 80-g glucose-H 2 ) was studied in 20 subjects with culture-documented small intestine bacterial overgrowth. Elevated breath 14 CO2 levels were seen within 30 min of [ 14 C]xylose administration in 19 of 20 subjects with bacterial overgrowth and 0 of 10 controls. In contrast, H 2 breath tests demonstrated uninterpretable tests (absence of H 2 -generating bacteria) in 2 of 20 subjects with bacterial overgrowth and 1 of 10 controls and nondiagnostic increases in H 2 production in 3 of 18 glucose-H 2 and 7 of 18 lactulose-H 2 breath tests in subjects with bacterial overgrowth. These findings demonstrate continued excellent reliability of the 1-g [ 14 C]xylose breath test as a diagnostic test for bacterial overgrowth, indicate inadequate sensitivity of H 2 breath tests in detecting bacterial overgrowth, and suggest the need for evaluation of a 13 CO 2 breath test having the same characteristics as the [ 14 C]xylose test (avidly absorbed substrate having minimal contact with the colonic flora) for nonradioactive breath detection of bacterial overgrowth in children and reproductive-age women

  17. The 14C-monomethylamino-antipyrine breath test as in vivo parameter for characterizing the induction of the drug catabolizing enzyme system in the guinea pig

    International Nuclear Information System (INIS)

    Gramatzki, S.

    1981-01-01

    The aim of these investigations was to help clarify the following questions: 1) Does MAAP, following 14 C labelling of the exocyclic aminomethyl group, offer a suitable substrate for a breath test in guinea pigs. 2) Which procedures for evaluating the 14 C exhalation curves of the breath test are especially valid. 3) Can an induction of the drug catabolizing enzyme system following pre-treatment with various inducing substances be detected by the 14 C-MAAP breath test. 4) Do inducer-specific differences arise in response to the 14 C-MAAP breath test by which the inducers can be characterized. 5) Is monomethylamino-antipyrine similar to amidopyrine in that it is a suitable independent in vivo parameter for the drug metasbolizing enzyme system in the liver of guinea pigs. (orig./MG) [de

  18. Estimation of Insulin Resistance in Mexican Adults by the [13C]Glucose Breath Test Corrected for Endogenous Total CO2 Production

    Directory of Open Access Journals (Sweden)

    Erika Ibarra-Pastrana

    2012-01-01

    Full Text Available Objective. To evaluate the efficacy of the [13C]glucose breath test for measuring insulin resistance in Mexican adults with different glycemic states. Research Design and Methods. Fifty-eight adults underwent a [13C]glucose breath test with simultaneous measurement of total CO2 production by indirect calorimetry, at baseline and 90 minutes after the ingestion of 15 g of dextrose and 25 mg of [13C]glucose. HOMA was used as a marker of insulin resistance. Results. We found an inverse correlation between HOMA and the breath test δ13CO2 (‰, r=-0.41 (P=0.001. After adjusting for total CO2 production, correlations between HOMA and fasting glucose were less strong but remained significant. An ROC curve was constructed using δ13CO2 (‰ and HOMA values; the cut-off point was 9.99‰ δ13CO2, corresponding to a sensitivity of 80.0 (95% CI: 51.9, 95.7 and a specificity of 67.4 (95% CI: 51.5, 80.9. Conclusions. The [13C]glucose breath test is a simple noninvasive procedure but was not sufficiently robust for an accurate diagnosis of insulin resistance. Our findings suggest that the test might be helpful in identifying individuals who are not IR, which in turn may contribute to improved diabetes prevention.

  19. Experience with the 14C-aminopyrine breath test in hepatic cirrhosis and under the influence of diclofenac-sodium (Voltaren/sup R/)

    International Nuclear Information System (INIS)

    Reinicke, C.; Hippius, M.

    1983-01-01

    The 14 C-aminopyrine breath test is a simple procedure for the non-invasive determination of the microsomal function of the liver. After oral administration of 74 kBq 14 C-aminopyrine the 14 CO 2 activity of the expired breath air is determined in hourly intervals. There is a close correlation between its decrease and the elimination of aminopyrine from the plasma. Both the elimination constant of 14 CO 2 and the maximal specific 14 CO 2 activity are useful quantitative parameters of the test. They allow conclusions as to the hepatic demethylation capacity. Both parameters were significantly lower in 15 patients with liver cirrhosis than in 12 control patients. The non-steroidal anti-inflammatory drug diclofenac-sodium did not significantly influence the demethylation of 14 C-aminopyrine in 5 patients with rheumatic diseases and in 2 healthy probands. Further experience with the breath test is necessary, especially with respect to its suitability for prospective investigation. (author)

  20. Determining urea levels in exhaled breath condensate with minimal preparation steps and classic LC-MS.

    Science.gov (United States)

    Pitiranggon, Masha; Perzanowski, Matthew S; Kinney, Patrick L; Xu, Dongqun; Chillrud, Steven N; Yan, Beizhan

    2014-10-01

    Exhaled breath condensate (EBC) provides a relatively easy, non-invasive method for measuring biomarkers of inflammation and oxidative stress in the airways. However, the levels of these biomarkers in EBC are influenced, not only by their levels in lung lining fluid but also by the volume of water vapor that also condenses during EBC collection. For this reason, the use of a biomarker of dilution has been recommended. Urea has been proposed and utilized as a promising dilution biomarker due to its even distribution throughout the body and relatively low volatility. Current EBC urea analytical methods either are not sensitive enough, necessitating large volumes of EBC, or are labor intensive, requiring a derivatization step or other pretreatment. We report here a straightforward and reliable LC-MS approach that we developed that does not require derivatization or large sample volume (∼36 µL). An Acclaim mixed-mode hydrophilic interaction chromatography column was selected because it can produce good peak symmetry and efficiently separate urea from other polar and nonpolar compounds. To achieve a high recovery rate, a slow and incomplete evaporation method was used followed by a solvent-phase exchange. Among EBC samples collected from 28 children, urea levels were found to be highly variable, with a relative standard deviation of 234%, suggesting high variability in dilution of the lung lining fluid component of EBC. The limit of detection was found to be 0.036 µg/mL. Published by Oxford University Press [2013]. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  1. Evaluation of a simple non-invasive 13C breath test to evaluate diet effects on gastric emptying in pigs

    DEFF Research Database (Denmark)

    Jørgensen, Henry; Strathe, Anders Bjerring; Theil, Peter Kappel

    2010-01-01

    to feeding (15.5 h after the previous meal) on the day when the 5 h sample was taken. In the breath test four pregnant sows were placed in respiration chambers and the 13C marker was added in the morning meal and air samples were collected up to 18 h at the outlet from the chambers and detected on an infra...... of the gastric content. Thus, the breath test is applicable for evaluating dietary effects on gastric emptying and potentially improves the behaviour and well being of gestating sows and lends confidence to applicability in clinical human trials....

  2. BUN (Blood Urea Nitrogen): MedlinePlus Lab Test Information

    Science.gov (United States)

    ... https://medlineplus.gov/labtests/bunbloodureanitrogen.html BUN (Blood Urea Nitrogen) To use the sharing features on this ... please enable JavaScript. What is a BUN (Blood Urea Nitrogen) Test? A BUN, or blood urea nitrogen ...

  3. A simple breath test for fat malabsorption in man

    International Nuclear Information System (INIS)

    Talbot, J.N.; Coutris, G.; Milhaud, G.

    1980-01-01

    The metabolic pathway of 14 C-labeled oleic acid leads to the formation and the breath excretion of 14 CO 2 . This behavior can be used for measuring lipid absorption. The simple, accurate screening test includes the ingestion of 14 C-labeled triolein and the intermittent collection of breath 14 CO 2 in a trapping solution. The results are strongly correlated to the measurement of fecal fat. The use of carbon-14 in man should not be restricted, provided the labeled substrates are converted into rapidly excreted metabolites [fr

  4. Studies investigating the excretion of acetyl urea in the milk of dairy cows receiving oral doses of 14C acetyl urea

    International Nuclear Information System (INIS)

    Bergner, H.; Kijora, C.; Goersch, R.

    1976-01-01

    2 experimental cows were fed acetyl urea several weeks before the trial was started. The first cow received a daily amount of 200 g and the second cow 855 g. On the first day of experiment both cows were given 5 mCi of 14 C acetyl urea intraruminally. Up to 6 hrs after the beginning of the experiment acetyl urea in blood plasma was shown to contain a higher proportion of 14 C activity than urea. 0.21 g urea and 0.18 g acetyl urea were contained in 1 kg of milk from cow No 1 while 1 kg of milk from cow No 2 contained 0.18 g urea and 0.12 g acetyl urea. The feeding of acetyl urea to dairy cows is not recommended on the basis of the fact that any further contamination of human nutrition with foreign substances should be possibly avoided. (author)

  5. Clinical Applications of CO2 and H2 Breath Test

    Directory of Open Access Journals (Sweden)

    ZHAO Si-qian;CHEN Bao-jun;LUO Zhi-fu

    2016-08-01

    Full Text Available Breath test is non-invasive, high sensitivity and high specificity. In this article, CO2 breath test, H2 breath test and their clinical applications were elaborated. The main applications of CO2 breath test include helicobacter pylori test, liver function detection, gastric emptying test, insulin resistance test, pancreatic exocrine secretion test, etc. H2 breath test can be applied in the diagnosis of lactose malabsorption and detecting small intestinal bacterial overgrowth. With further research, the breath test is expected to be applied in more diseases diagnosis.

  6. Examination of dialysis patients with the aminophenazone breath test

    International Nuclear Information System (INIS)

    Heinrich, H.G.; Adler, D.; Hornak, H.; Wuenschmann, H.J.; Mayer, W.K.

    1989-01-01

    In 12 endstage kidney disease patients (8 without and 4 with liver diseases) the activities of cytochrome P 450 -dependent mixed functional oxidases system (MFO) of the liver were studied by using the 14 C-aminophenazone breath test before and after dialysis. The results showed that uremia seems to have a pressing influence on MFO activity. The activity was only significantly increased after dialysis in the group of patients without liver diseases. The MFO activity was reduced in patients with liver diseases. This is a restriction of the hepatic metabolic demethylation capacity. It is unclear if the 14 C-aminophenazone breath test in dialysis patients is qualified to estimate metabolic capacity of the liver. Differentiation between the influence of uremia and of the liver disease on the alteration of MFO activity cannot be made. (author)

  7. Studies investigating the excretion of acetyl urea in the milk of dairy cows receiving oral doses of /sup 14/C acetyl urea

    Energy Technology Data Exchange (ETDEWEB)

    Bergner, H; Kijora, C; Goersch, R [Humboldt-Universitaet, Berlin (German Democratic Republic). Sektion Tierproduktion und Veterinaermedizin

    1976-01-01

    2 experimental cows were fed acetyl urea several weeks before the trial was started. The first cow received a daily amount of 200 g and the second cow 855 g. On the first day of experiment both cows were given 5 mCi of /sup 14/C acetyl urea intraruminally. Up to 6 hrs after the beginning of the experiment acetyl urea in blood plasma was shown to contain a higher proportion of /sup 14/C activity than urea. 0.21 g urea and 0.18 g acetyl urea were contained in 1 kg of milk from cow No 1 while 1 kg of milk from cow No 2 contained 0.18 g urea and 0.12 g acetyl urea. The feeding of acetyl urea to dairy cows is not recommended on the basis of the fact that any further contamination of human nutrition with foreign substances should be possibly avoided.

  8. 21 CFR 862.3050 - Breath-alcohol test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breath-alcohol test system. 862.3050 Section 862.3050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened...

  9. Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults

    OpenAIRE

    Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

    2015-01-01

    Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia.

  10. 21 CFR 862.3080 - Breath nitric oxide test system.

    Science.gov (United States)

    2010-04-01

    ... Systems § 862.3080 Breath nitric oxide test system. (a) Identification. A breath nitric oxide test system... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breath nitric oxide test system. 862.3080 Section... fractional nitric oxide concentration in expired breath aids in evaluating an asthma patient's response to...

  11. Simultaneous 13C/14C dual isotope breath test measurement of gastric emptying of solid and liquid in normal subjects and patients: comparison with scintigraphy

    International Nuclear Information System (INIS)

    Chew, C. G.; Bartholomeusz, F.D.L.; Bellon, M.; Chatterton, B. E.

    2003-01-01

    To develop a simple method for simultaneous solid and liquid gastric emptying assessment using a dual isotope labelled breath test. 13 patients were given 100 g ground beef labelled with 25 MBq 99m Tc sulphur colloid and 74 KBq 14 C octanoic acid, and 150 ml 10% glucose drink labelled with 8 MBq 67 Ga citrate and 150 mg 13 C acetate. 10 normal volunteers were given the same test meals but labelled with 14 C and 13 C only. Breath was collected at baseline and regularly for 4 hours. The 14 CO 2 and 13 CO 2 activity was measured with liquid scintillation counting and mass spectroscopy. The times to maximum 14 CO 2 and 13 CO 2 , were determined. Comparison was made between times to maximum 14 CO 2 with scintigraphic retention of 99m Tc at 100 minutes and times to maximum 13 CO 2 with the scintigraphic half-clearance time of 67 Ga. For the solid meal, the times to maximum 14 CO 2 were: 60-120 minutes in the 8 patients with normal gastric emptying of 99m Tc; 75-145 minutes for the 10 healthy volunteers; 75-180 minutes for the remaining 5 patients with abnormal gastric emptying of 99m Tc. There was a weak but significant correlation (r = 0.56, p 14 CO 2 and gastric retention of 99m Tc at 100 minutes. For the liquid meal, times to maximum 13 CO 2 were: 20-35 minutes for the 4 with normal gastric emptying of 67 Ga; 15-40 minutes for the 10 healthy volunteers; 20-75 minutes for the remaining 9 patients with abnormal gastric emptying of 67 Ga. There was a strong and significant correlation (r = 0.88, p 13 CO 2 and gastric half-clearance time of 67 Ga. Breath tests utilising test meals labelled with *C isotopes are valid alternatives to scintigraphic studies using 99m Tc and 67 Ga for the simultaneous assessment of gastric emptying of solids and liquids. (author)

  12. Urea metabolism in cattle and buffaloes fed diets containing NPN salts, usin g urea radiotracers

    International Nuclear Information System (INIS)

    Dhiman, T.R.; Arora, S.P.

    1990-01-01

    Urea metabolism studies were conducted using isotope dilution techniques. Animals in groups 1 and 3 were fed basal diet (S, 0.11%) supplemented with urea (test diet 1) and those of groups 2 and 4 supplemented urea plus ammonium sulphate (test diet 2) containing 0.22% S. A single injection of a mixture of 15 N-urea and 14 C-urea was given intravenously and 51 Cr-EDTA was given as a single infusion intraruminally. The pattern of release of ammonia, mean ruminal ammonia, plasma urea, rumen fluid outflow rate, rumen ammonia pool size and ammonia outflow from rumen remained unaffected due to different dietary treatments. On an average, 73.3% of plasma urea synthesized was excreted in urine with test diet 1 and showing 26.6% degradation in the gastrointestinal tract, whereas 68.8% was excreted with test diet 2 and showing 31.3% degradation in the gastrointestinal tract. At 24 hr, 18.33 to 20.93% of nitrogen entering the ruminal ammonia pool was derived from plasma urea in calves of groups 1 and 2 and 24.22 to 27.49 in buffalo calves of groups 3 and 4 respectively. Sulphur supplementation through ammonium sulphate (N : S, 10 :1) resulted in better utilization of nitrogen with test diet 2 by lowering urea excretion rate and increasing urea recycling rate in both the species. (author). 5 tabs., 16 refs

  13. Hyperpolarized 13C-Urea MRI for the assessment of the urea gradient in the porcine kidney

    DEFF Research Database (Denmark)

    Søvsø Szocska Hansen, Esben; Stewart, Neil James; Wild, Jim Michael

    Renal anatomical and pathophysiological alterations are directly associated with the fluid and electrolyte balance in the kidney, which is regulated by the extracellular corticomedullary osmolality gradient. We introduce a novel magnetic resonance imaging (MRI) approach to monitor...... treatment resulted in an increased urea accumulation in the cortical space. This work demonstrates intra-renal functional assessment with hyperpolarized 13C-urea MRI in multi-papillary kidneys....

  14. Breath tests: principles, problems, and promise

    International Nuclear Information System (INIS)

    Lo, C.W.; Carter, E.A.; Walker, W.A.

    1982-01-01

    Breath tests rely on the measurement of gases produced in the intestine, absorbed, and expired in the breath. Carbohydrates, such as lactose and sucrose, can be administered in ysiologic doses; if malabsorbed, they will be metabolized to hydrogen by colonic bacteria. Since hydrogen is not produced by human metabolic reactions, a rise in breath hydrogen, as measured by gas chromatography, is evidence of carbohydrate malabsorption. Likewise, a rise in breath hydrogen marks the transit time of nonabsorbable carbohydrates such as lactulose through the small intestine into the colon. Simple end-expiratory interval collection into nonsiliconized vacutainer tubes has made these noninvasive tests quite convenient to perform, but various problems, including changes in stool pH intestinal motility, or metabolic rate, may influence results. Another group of breath tests uses substrates labeled with radioactive or stable isotopes of carbon. Labeled fat substrates such as trioctanoin, tripalmitin, and triolein do not produce the expected rise in labeled breath CO 2 if there is fat malabsorption. Bile acid malabsorption and small intestinal bacterial overgrowth can be measured with labeled cholylglycine or cholyltaurine. Labeled drugs such as aminopyrine, methacetin, and phenacetin can be used as an indication of drug metabolism and liver function. Radioactive substrates have been used to trace metabolic pathways and can be measured by scintillation counters. The availability of nonradioactive stable isotopes has made these ideal for use in children and pregnant women, but the cost of substrates and the mass spectrometers to measure them has so far limited their use to research centers. It is hoped that new techniques of processing and measurement will allow further realization of the exciting potential breath analysis has in a growing list of clinical applications

  15. The synthesis of no-carrier-added [11C]urea from [11C]carbon dioxide and application to [11C]uracil synthesis

    International Nuclear Information System (INIS)

    Chakraborty, P.K.; Mangner, T.J.; Chugani, H.T.

    1997-01-01

    No-carrier-added [ 11 C]urea has been synthesized by bubbling cyclotron-produced [ 11 C]-carbon dioxide directly into a tetrahydrofuran solution of lithium bis(trimethylsilyl)amide, followed by hydrolysis of the C-11 labeled adduct with aqueous ammonium chloride. Using this simple, one-pot method, [ 11 C]urea was produced in 55-70% radiochemical yield (decay-corrected) in 16 min following end-of-bombardment (or in 10 min following the introduction of the [ 11 C]carbon dioxide. The [ 11 C]urea thus produced was converted to [ 11 C]uracil (carrier-added) in 40-75% decay-corrected radiochemical yield by condensation with diethyl malate in presence of fuming sulfuric acid. (author)

  16. Minimal sampling protocol for accurate estimation of urea production: a study with oral [13C]urea in fed and fasted piglets

    NARCIS (Netherlands)

    Oosterveld, Michiel J. S.; Gemke, Reinoud J. B. J.; Dainty, Jack R.; Kulik, Willem; Jakobs, Cornelis; de Meer, Kees

    2005-01-01

    An oral [13C]urea protocol may provide a simple method for measurement of urea production. The validity of single pool calculations in relation to a reduced sampling protocol was assessed. In eight fed and five fasted piglets, plasma urea enrichments from a 10 h sampling protocol were measured

  17. Two-stage triolein breath test differentiates pancreatic insufficiency from other causes of malabsorption

    International Nuclear Information System (INIS)

    Goff, J.S.

    1982-01-01

    In 24 patients with malabsorption, [ 14 C]triolein breath tests were conducted before and together with the administration of pancreatic enzymes (Pancrease, Johnson and Johnson, Skillman, N.J.). Eleven patients with pancreatic insufficiency had a significant rise in peak percent dose per hour 14 CO 2 excretion after Pancrease, whereas 13 patients with other causes of malabsorption had no increase in 14 CO 2 excretion (2.61 +/- 0.96 vs. 0.15 +/- 0.45, p less than 0.001). The two-stage [ 14 C]triolein breath test appears to be an accurate and simple noninvasive test of fat malabsorption that differentiates steatorrhea secondary to pancreatic insufficiency from other causes of steatorrhea

  18. 14C-lactose breath tests during pelvic radiotherapy: the effect of the amount of small bowel irradiated

    International Nuclear Information System (INIS)

    Weiss, R.G.; Stryker, J.A.

    1982-01-01

    Thirty patients who were undergoing pelvic radiotherapy had 14 C-lactose breath tests performed in the first and fifth weeks of treatment. In Group I (21 patients), a significant portion of the small intestine was irradiated, and in Group II (9 patients), only a small portion of the small intestine was irradiated. In Group I, the average reductions in the excretion of ingested 14 C between the first- and fifth-week tests were 41.5% at 1/2 hour postingestion (p 0.05). The data suggest that lactose malabsorption is a factor in the etiology of the nausea, vomiting, and diarrhea experienced by patients who are undergoing pelvic radiotherapy, and that the amount of bowel included in the treatment volume significantly influences the degree of malabsorption

  19. The accuracy of the Helicobacter pylori stool antigen test in diagnosing H-pylori in treated and untreated patients

    NARCIS (Netherlands)

    Arents, NL; van Zwet, AA; Thijs, JC; de Jong, A; Pool, MO; Kleibeuker, JH

    Objective and design To evaluate the performance of the Helicobacter pylori stool antigen test (HpSA test) in detecting H. pylori infection and monitoring the effect of treatment. This was done in two separate studies using either a biopsy or the C-13-urea breath test based 'gold standard' (in

  20. Breath tests and irritable bowel syndrome.

    Science.gov (United States)

    Rana, Satya Vati; Malik, Aastha

    2014-06-28

    Breath tests are non-invasive tests and can detect H₂ and CH₄ gases which are produced by bacterial fermentation of unabsorbed intestinal carbohydrate and are excreted in the breath. These tests are used in the diagnosis of carbohydrate malabsorption, small intestinal bacterial overgrowth, and for measuring the orocecal transit time. Malabsorption of carbohydrates is a key trigger of irritable bowel syndrome (IBS)-type symptoms such as diarrhea and/or constipation, bloating, excess flatulence, headaches and lack of energy. Abdominal bloating is a common nonspecific symptom which can negatively impact quality of life. It may reflect dietary imbalance, such as excess fiber intake, or may be a manifestation of IBS. However, bloating may also represent small intestinal bacterial overgrowth. Patients with persistent symptoms of abdominal bloating and distension despite dietary interventions should be referred for H₂ breath testing to determine the presence or absence of bacterial overgrowth. If bacterial overgrowth is identified, patients are typically treated with antibiotics. Evaluation of IBS generally includes testing of other disorders that cause similar symptoms. Carbohydrate malabsorption (lactose, fructose, sorbitol) can cause abdominal fullness, bloating, nausea, abdominal pain, flatulence, and diarrhea, which are similar to the symptoms of IBS. However, it is unclear if these digestive disorders contribute to or cause the symptoms of IBS. Research studies show that a proper diagnosis and effective dietary intervention significantly reduces the severity and frequency of gastrointestinal symptoms in IBS. Thus, diagnosis of malabsorption of these carbohydrates in IBS using a breath test is very important to guide the clinician in the proper treatment of IBS patients.

  1. Comparison of diagnostic accuracy of non invasive tests for helicobacter pylori infection in children

    International Nuclear Information System (INIS)

    Hafeez, A.; Haseeb, H.A.H.; Bilal, R.; Latif, Z.

    2007-01-01

    To compare urea breath and stool antigen in children, with histological diagnosis for Helicobacter pylori (H.pylori) infection. Children between 3 and 15 years of age reporting in pediatric outpatient department with upper gastrointestinal symptoms were included. All the participating children underwent an upper gastrointestinal endoscopy and 3 tests namely: histopathological identification of H. pylori (the traditional gold standard), urea breath test and stool antigen test were carried out on each child. The sensitivity, specificity, and positive predictive values were calculated for each noninvasive test used in the study. A total of 54 patients completed the study with a mean age of 8.2 years. On histological examination, 72% (39) were positive for H. pylori infection. On gross endoscopic examination, only 9 patients had signs of gastritis as compared to 39 histological positives. The sensitivity, specificity and positive predictive value of stool antigen test were: 77%, 73% and 89% respectively whereas the same for urea breath test were: 79%, 80% and 91% respectively. Both the noninvasive tests were found to be sensitive and specific as compared with histological identification, for the diagnosis of H. pylori in our pediatric population. The accuracy of urea breath test was better than the stool antigen test but later was easier to perform and could fulfill the criteria for a rapid bedside diagnostic test. (author)

  2. The glucose breath test: a diagnostic test for small bowel stricture(s) in Crohn's disease.

    Science.gov (United States)

    Mishkin, Daniel; Boston, Francis M; Blank, David; Yalovsky, Morty; Mishkin, Seymour

    2002-03-01

    The aim of this study was to determine whether an indirect noninvasive indicator of proximal bacterial overgrowth, the glucose breath test, was of diagnostic value in inflammatory bowel disease. Twenty four of 71 Crohn's disease patients tested had a positive glucose breath test. No statistical conclusions could be drawn between the Crohn's disease activity index and glucose breath test status. Of patients with radiologic evidence of small bowel stricture(s), 96.0% had a positive glucose breath test, while only one of 46 negative glucose breath test patients had a stricture. The positive and negative predictive values for a positive glucose breath test as an indicator of stricture formation were 96.0% and 97.8%, respectively. This correlation was not altered in Crohn's disease patients with fistulae or status postresection of the terminal ileum. The data in ulcerative colitis were nondiagnostic. In conclusion, the glucose breath test appears to be an accurate noninvasive inexpensive diagnostic test for small bowel stricture(s) and secondary bacterial overgrowth in Crohn's disease.

  3. Detection of Helicobacter pylori in rural school children using 13C ...

    African Journals Online (AJOL)

    ulcer, gastric ulcer, non-ulcer dyspepsia and gastritis. Several diagnostic methods are available for the detection of H. pylori, with direct methods based on gastric biopsies. The 13C- Urea Breath Test (UBT) used in this study has advantage over the other methods in that, it is easy to perform, specific (100%), highly sensitive ...

  4. Breath test measurements in combination with indirect calorimetry for estimation of 13C-leucine oxidation in mink (Mustela vison)

    DEFF Research Database (Denmark)

    Tauson, Anne-Helene; Ali, Abdalla; Kanska, Katarzyna

    2000-01-01

    Gas exchange measurements by means of indirect calorimetry can be used to calculate quantitative substrate oxidation. The results represents average net oxidation values (substrate disappearance rate), but they cannot describe the dynamics of the oxidation processes. Breath test measurements...... to feeding and fasting. Twelve 1-year-old male mink (Mustela vison) were measured in each five consecutive periods by means of indirect calorimetry and simultaneous breath test. In Periods 1, 3 and 5, each lasting 3 days, the animals were fed ad libitum and Periods 2 and 4 were fasting periods, each of 48 h....... In Periods 1 and 5 all animals were fed a diet with a high quality fish meal (FISH; n=12), while in Period 3 half of the animals received the FISH diet (n=6) and the other half a diet with soy protein concentrate (SOY; n=6) as main protein source. An intraperitoneal injection of 1-13C-leucine was given...

  5. 13C/14C dual isotope breath test measurement of gastric emptying in normal subjects and patients

    International Nuclear Information System (INIS)

    Chew, G.; Bartholomeusz, F.D.L.; Bellon, M.; Chatterton, B.E.

    2000-01-01

    Full text: A more flexible alternative to dual isotope scintigraphy for gastric emptying involves measuring breath C0 2 after administration of absorbable tracers. Method: six patients were given 100g hamburger labelled with 25 MBq 99 Tc m sulphur colloid and 74 KBq 14 C octanoic acid, and 150 ml 10% glucose drink labelled with 8 MBq 67 Ga citrate and ISO mg 13 C acetate and seven normals with 14 C and 13 C labels only. Breath was collected at baseline and then regularly for four hours. The 14 CO 2 and 13 CO 2 activity was measured with liquid scintillation counting and mass spectroscopy. The times to maximum 14 CO 2 , and 13 CO 2 , T max, were determined. Results: Comparison was made between 14 CO 2 T max with scintigraphic retention of 99 Tc m at 100 minutes (SR100m) and 13 CO 2 T max with the scintigraphic half-clearance time of 67 Ga (scint T1/2). In conclusion 14 CO 2 T max and 13 CO 2 T max correlate significantly with SR100m and scint T1/2 respectively. The normal threshold is between 165 and 180 minutes for 14 Co 2 T max; probably > 40 minutes for 13 CO 2 T max but overlap exists between normal and abnormal results in this small preliminary study. Recruitment is to continue to better define normal ranges. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  6. Rapid point-of-care breath test for biomarkers of breast cancer and abnormal mammograms.

    Directory of Open Access Journals (Sweden)

    Michael Phillips

    Full Text Available BACKGROUND: Previous studies have reported volatile organic compounds (VOCs in breath as biomarkers of breast cancer and abnormal mammograms, apparently resulting from increased oxidative stress and cytochrome p450 induction. We evaluated a six-minute point-of-care breath test for VOC biomarkers in women screened for breast cancer at centers in the USA and the Netherlands. METHODS: 244 women had a screening mammogram (93/37 normal/abnormal or a breast biopsy (cancer/no cancer 35/79. A mobile point-of-care system collected and concentrated breath and air VOCs for analysis with gas chromatography and surface acoustic wave detection. Chromatograms were segmented into a time series of alveolar gradients (breath minus room air. Segmental alveolar gradients were ranked as candidate biomarkers by C-statistic value (area under curve [AUC] of receiver operating characteristic [ROC] curve. Multivariate predictive algorithms were constructed employing significant biomarkers identified with multiple Monte Carlo simulations and cross validated with a leave-one-out (LOO procedure. RESULTS: Performance of breath biomarker algorithms was determined in three groups: breast cancer on biopsy versus normal screening mammograms (81.8% sensitivity, 70.0% specificity, accuracy 79% (73% on LOO [C-statistic value], negative predictive value 99.9%; normal versus abnormal screening mammograms (86.5% sensitivity, 66.7% specificity, accuracy 83%, 62% on LOO; and cancer versus no cancer on breast biopsy (75.8% sensitivity, 74.0% specificity, accuracy 78%, 67% on LOO. CONCLUSIONS: A pilot study of a six-minute point-of-care breath test for volatile biomarkers accurately identified women with breast cancer and with abnormal mammograms. Breath testing could potentially reduce the number of needless mammograms without loss of diagnostic sensitivity.

  7. A rapid non invasive L-DOPA-¹³C breath test for optimally suppressing extracerebral AADC enzyme activity - toward individualizing carbidopa therapy in Parkinson’s disease.

    Science.gov (United States)

    Modak, Anil; Durso, Raymon; Josephs, Ephraim; Rosen, David

    2012-01-01

    Peripheral carbidopa (CD) levels directly impact on central dopamine (DA) production in Parkinson disease (PD) through extracerebral inhibition of dopa decarboxylase (AADC) resulting in an increase in levodopa (LD) bioavailability. Recent data suggests that higher CD doses than those presently used in PD treatment may result in improved clinical response. Optimizing CD doses in individual patients may, therefore, result in ideal individualized treatment. A single center, randomized, double-blind study was carried out recruiting 5 Parkinson’s disease (PD) patients already on LD/CD and 1 treatment näve PD patient using stable isotope labeled LD-1-¹³C as a substrate for a noninvasive breath test to evaluate individual AADC enzyme activity. Each patient was studied five times, receiving 200 mg LD-¹³C at each visit along with one of five randomized CD doses (0, 25, 50, 100 and 200 mg). The metabolite ¹³CO₂ in breath was measured for evaluating AADC enzyme activity and plasma metabolite levels for LD-¹³C and homovanillic acid (HVA) were measured for 4 hours. HVA in plasma and ¹³CO₂ in breath are metabolic products of LD. We found a significant positive correlation of ¹³CO₂ DOB AUC0-240 with serum HVA AUC0-240 following the oral dose of LD-1-¹³C for all 5 doses of CD (r² = 0.9378). With increasing inhibition of AADC enzyme activity with CD, we observed an increase in the plasma concentration of LD.We found an inverse correlation of the 13CO2 DOB AUC with serum LD-¹³C AUC. Our studies indicate the optimal dose of CD for maximal suppression of AADC enzyme activity can be determined for each individual from ¹³CO₂ generation in breath. The LD-breath test can be a useful noninvasive diagnostic tool for evaluation of AADC enzyme activity using the biomarker ¹³CO₂ in breath, a first step in personalizing CD doses for PD patients.

  8. Effect of an ntrC mutation on amino acid or urea utilization and on nitrogenase switch-off in Herbaspirillum seropedicae.

    Science.gov (United States)

    Gusso, Claudio L; de Souza, Emanuel M; Rigo, Liu Un; de Oliveira Pedrosa, Fábio; Yates, M G; de M Rego, Fabiane G; Klassen, Giseli

    2008-03-01

    Herbaspirillum seropedicae is a nitrogen-fixing bacterium that grows well with ammonium chloride or sodium nitrate as alternative single nitrogen sources but that grows more slowly with L-alanine, L-serine, L-proline, or urea. The ntrC mutant strain DCP286A was able to utilize only ammonium or urea of these nitrogen sources. The addition of 1 mmol.L-1 ammonium chloride to the nitrogen-fixing wild-type strain inhibited nitrogenase activity rapidly and completely. Urea was a less effective inhibitor; approximately 20% of nitrogenase activity remained 40 min after the addition of 1 mmol x L-1 urea. The effect of the ntrC mutation on nitrogenase inhibition (switch-off) was studied in strain DCP286A containing the constitutively expressed gene nifA of H. seropedicae. In this strain, nitrogenase inhibition by ammonium was completely abolished, but the addition of urea produced a reduction in nitrogenase activity similar to that of the wild-type strain. The results suggest that the NtrC protein is required for assimilation of nitrate and the tested amino acids by H. seropedicae. Furthermore, NtrC is also necessary for ammonium-induced switch-off of nitrogenase but is not involved in the mechanism of nitrogenase switch-off by urea.

  9. On the importance of developing a new generation of breath tests for Helicobacter pylori detection.

    Science.gov (United States)

    Kushch, Ievgeniia; Korenev, Nikolai; Kamarchuk, Lyudmila; Pospelov, Alexander; Kravchenko, Andrey; Bajenov, Leonid; Kabulov, Mels; Amann, Anton; Kamarchuk, Gennadii

    2015-12-15

    State-of-the-art methods for non-invasive detection of the Helicobacter pylori (H. pylori) infection have been considered. A reported global tendency towards a non-decreasing prevalence of H. pylori worldwide could be co-influenced by the functional limitations of urea breath tests (UBTs), currently preferred for the non-invasive recognition of H. pylori in a clinical setting. Namely, the UBTs can demonstrate false-positive or false-negative results. Within this context, limitations of conventional clinically exploited H. pylori tests have been discussed to justify the existing need for the development of a new generation of breath tests for the detection of H. pylori and the differentiation of pathogenic and non-pathogenic strains of the bacterium. This paper presents the results of a pilot clinical study aimed at evaluating the development and diagnostic potential of a new method based on the detection of the non-urease products of H. pylori vital activity in exhaled gas. The characteristics of breath of adolescents with H. pylori-positive and H. pylori-negative functional dyspepsia, together with a consideration of the cytotoxin-associated gene A (CagA) status of H. pylori-positive subjects, have been determined for the first time using innovative point-contact nanosensor devices based on salts of the organic conductor tetracyanoquinodimethane (TCNQ). The clinical and diagnostic relevance of the response curves of the point-contact sensors was assessed. It was found that the recovery time of the point-contact sensors has a diagnostic value for differentiation of the H. pylori-associated peptic ulcer disease. The diagnostically significant elongation of the recovery time was even more pronounced in patients infected with CagA-positive H. pylori strains compared to the CagA-negative patients. Taking into account the operation of the point-contact sensors in the real-time mode, the obtained results are essential prerequisites for the development of a fast and

  10. Synthesis of 13N and/or 11C single or doubly labelled urea

    International Nuclear Information System (INIS)

    Emran, A.M.

    1989-01-01

    Utilization of nitrogen by plants encounters two important problems which are denitrification and deficiency or inactivation of certain enzyme. In the first process the fertilizer is affected by certain bacteria to produce nitrogen or its oxides which cannot be utilized by plants. In the second process, transformation of urea nitrogen into forms usable by plants depends on abundance and activity of the enzyme urease. Study of inorganic nitrogen transport has been underway using 13 N-nitrate as a tracer. Behavior of organic nitrogen can be studied using labelled urea. [ 13 N] and/or [ 11 C] single or doubly labelled urea are good tracers for this purpose. Reaction of trace amounts of potassium cyanate with 13 N-ammonium sulfate produced 13 N-ammonium cyanate which was thermally transformed into [ 13 N]-urea with no added carrier. Similarly, [ 11 C]-potassium cyanate reacted with 13 N-ammonium sulfate to produce 13 N/ 11 C-doubly labelled urea. Thin layer and high performance liquid chromatography were used to identify the products and determine the yields

  11. 13C-octanoic acid breath test for measurement of solid gastric emptying: reproducibility in normal subjects and patients with diabetes mellitus

    International Nuclear Information System (INIS)

    Feng Bo; Dan, Z.

    2001-01-01

    Objective: To examine the intra-individual reproducibility of the octanoic acid breath test in normal subjects and diabetics and to investigate whether cardiovascular autonomic neuropathy and delayed gastric emptying influence the intra-individual reproducibility. Methods: Nine normal subjects (six men, three women,mean age 38 years) and 15 diabetics with insulin treatment [nine men, six women; mean age 47 years; six had cardiovascular autonomic diabetic neuropathy (CADN) and/or delayed gastric emptying time] were, after a nocturnal fasting period, given a standard test meal (labelled with 13 C-octanoic acid, 1 046 kJ). Breath samples were taken at ten minute intervals over first one hour and at fifteen minute intervals over the following three hours and examined for 13 CO 2 by isotope ratio infrared spectrometry. Using a regression method gastric emptying half times (t 1/2 ) and lag phase (t lag ) were determined. Results: There was not a significant difference of t 1/2 and t lag between two measurements in normal subjects and diabetics. The coefficients of variation of day-to-day reproducibility were 11.7% for t 1/2 , 19.4% for t lag in normal subjects and 17.8% for t 1/2 , 28.2% for t lag in diabetics, but there was not significant difference between normal subjects and diabetics. There was not significant difference of intra-individual coefficient of variation of t 1/2 and t lag between diabetics with/without CADN and between diabetics with normal gastric emptying time and diabetics with delayed gastric emptying time. Conclusions: The 13 C-octanoic acid breath test has a high intra-individual reproducibility which is not affected by the cardiovascular autonomic neuropathy and delayed gastric emptying. It can be recommended as a non-invasive test for assessing gastric emptying time after a solid test meal in diabetics

  12. Urea metabolism in Barbari kids d on urea molasses diets

    International Nuclear Information System (INIS)

    Lal, M.; Singh, U.B.; Verma, D.N.; Ranjhan, S.K.

    1974-01-01

    The entry rates of urea into the body pool of urea were estimated in Barbari kids using a single injection isotope dilution technique using 14 C-urea. The excretion rates of urea were calculated by estimating total urine output over 24 h and urea content. (M.G.B.)

  13. Variations in colonic H-2 and CO2 production as a cause of inadequate diagnosis of carbohydrate maldigestion in breath tests

    NARCIS (Netherlands)

    Koetse, HA; Vonk, RJ; Pasterkamp, S; de Bruijn, S; Stellaard, F

    Background: Lactose maldigestion is usually diagnosed by means of the H-2 breath test. When C-13-lactose is used as substrate, a (CO2)-C-13 breath rest can be performed simultaneously. In an earlier publication we described the relation between both the H2 and (CO2)-C-13 exhalation in breath and the

  14. GC-MS DETERMINATION OF RATIOS OF STABLE-ISOTOPE LABELED TO NATURAL UREA USING [(CN2)-C-13-N-15]UREA FOR STUDYING UREA KINETICS IN SERUM AND AS A MEANS TO VALIDATE ROUTINE METHODS FOR THE QUANTITATIVE ASSAY OF UREA IN DIALYSATE

    NARCIS (Netherlands)

    WOLTHERS, BG; TEPPER, T; WITHAG, A; NAGEL, GT; DEHAAN, THY; VANLEEUWEN, JJ; STEGEMAN, CA; HUISMAN, RM

    A GC-MS determination of urea in serum or spent dialysate is described, using (CN2)-C-13-N-15-labelled urea and assaying the area ratio of labelled to natural urea by mass fragmentographic monitoring of fragments m/e 153 and 156, after its eventual conversion into the trimethylsilylether-derivative

  15. 14C-lactose breath tests during pelvic radiotherapy: the effect of the amount of small bowel irradiated

    International Nuclear Information System (INIS)

    Weiss, R.G.; Stryker, J.A.

    1982-01-01

    Thirty patients who were undergoing pelvic radiotherapy had 14 C-lactose breath tests performed in the first and fifth weeks of treatment. In Group I (21 patients), a significant portion of the small intestine was irradiated, and in Group II (9 patients), only a small portion of the small intestine was irradiated. In Group I, the average reductions in the excretion of ingested 14 C between the first- and fifth-week tests were 41.5% at 1/2 hour postingestion (p less than 0.05), and 21.8% at 1 hour postingestion (p less than 0.05). In Group II, the percentage reductions were 11.8% and 3.7% at 1/2 and 1 hour, respectively (p greater than 0.05). The data suggest that lactose malabsorption is a factor in the etiology of the nausea, vomiting, and diarrhea experienced by patients who are undergoing pelvic radiotherapy, and that the amount of bowel included in the treatment volume significantly influences the degree of malabsorption

  16. Entry of blood urea into the rumen of the llama

    International Nuclear Information System (INIS)

    Hinderer, S.; Engelhardt, W. von

    1976-01-01

    Transfer of body urea into the temporarily isolated rumen cleaned and filled with a test solution was measured in the llama. Simultaneously urea recirculation into the total gastro-intestinal tract (GI-tract) was estimated using 14 C-urea. The permeability of the rumen wall to urea could be changed significantly. With CO 2 or butyric acid in the test solution, permeability was highest, it was low when food was withheld and when no volatile fatty acids were present in the solution. Changes in the permeability can affect the transfer of blood urea across the rumen wall more extensively than changes in plasma urea concentrations. (author)

  17. Effect of alcohol consumption on the liver detoxication capacity as measured by [13C]methacetin- and [methyl-13C]methionine-breath tests.

    Science.gov (United States)

    Wutzke, Klaus D; Forberger, Anke; Wigger, Marianne

    2008-06-01

    The aim of this study was to investigate the hepatic microsomal and mitochondrial functions by using the 13CO2-breath test in healthy subjects either before or after the consumption of red wine. Fourteen adults received [13C]methacetin and [methyl-13C]methionine together with a standardised dinner. Expired air samples were taken over 6 h. After a wash-out period, the subjects consumed 0.4 ml ethanol/kg/day together with dinner over a 10-day period. Thereafter, 13C-tracer administration was repeated under identical conditions. The 13CO2-enrichments were measured by isotope ratio mass spectrometry. The mean cumulative percentage 13C-dose recovery (CPDR) after administration of [13C]methacetin and [methyl-13C]methionine either without or with red wine consumption amounted to 38.2+/-6.3 vs. 36.3+/-6.7% (p=0.363) and 9.5+/-3.3 vs. 8.8+/-2.5% (p=0.47), respectively. Moderate alcohol consumption does not induce significant short-term changes of the microsomal and the mitochondrial functions of the human liver in healthy subjects.

  18. The non-invasive 13C-methionine breath test detects hepatic mitochondrial dysfunction as a marker of disease activity in non-alcoholic steatohepatitis

    Directory of Open Access Journals (Sweden)

    Banasch M

    2012-06-01

    Full Text Available Abstract Introduction Mitochondrial dysfunction plays a central role in the general pathogenesis of non-alcoholic fatty liver disease (NAFLD, increasing the risk of developing steatosis and subsequent hepatocellular inflammation. We aimed to assess hepatic mitochondrial function by a non-invasive 13C-methionine breath test (MeBT in patients with histologically proven NAFLD. Methods 118 NAFLD-patients and 18 healthy controls were examined by MeBT. Liver biopsy specimens were evaluated according to the NASH scoring system. Results Higher grades of NASH activity and fibrosis were independently associated with a significant decrease in cumulative 13C-exhalation (expressed as cPDR(%. cPDR1.5h was markedly declined in patients with NASH and NASH cirrhosis compared to patients with simple steatosis or borderline diagnosis (cPDR1.5h: 3.24 ± 1.12% and 1.32 ± 0.94% vs. 6.36 ± 0.56% and 4.80 ± 0.88% respectively; p 13C-exhalation further declined in the presence of advanced fibrosis which was correlated with NASH activity (r = 0.36. The area under the ROC curve (AUROC for NASH diagnosis was estimated to be 0.87 in the total cohort and 0.83 in patients with no or mild fibrosis (F0-1. Conclusion The 13C-methionine breath test indicates mitochondrial dysfunction in non-alcoholic fatty liver disease and predicts higher stages of disease activity. It may, therefore, be a valuable diagnostic addition for longitudinal monitoring of hepatic (mitochondrial function in non-alcoholic fatty liver disease.

  19. Comparison of 72-hour fecal fat quantification and the 13C-mixed triglyceride breath test in assessing pancreatic exocrine sufficiency in children with chronic pancreatitis.

    Science.gov (United States)

    Wejnarska, Karolina; Kołodziejczyk, Elwira; Ryżko, Józef; Oracz, Grzegorz

    Chronic pancreatitis (CP) in children is still a rare, although increasingly recognized entity. Over the duration of the disease several complications can be observed, two of which are major ones: endo- and exocrine insufficiency. In the medical care of children with CP it is crucial to diagnose the decreased endo- and exocrine function of the pancreas, in order to preserve patients from malnutrition and the failure to thrive. The aim of the study was to compare the usefulness of two indirect methods of assessing the pancreas exocrine function in children with CP. Ninety one patients with CP were enrolled in the study (41 boys, 50 girls, aged 2-17.8 years). Only Patients who had had both the 72-hour fecal fat quantification and the 13C-mixed triglyceride breath test (13C -MTBT) performed were selected. We compared the results of both tests for sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) in detecting exocrine pancreatic insufficiency. Out of 91 patients, 12 were diagnosed with exocrine pancreatic insufficiency (EPI). The sensitivity of the fecal fat quantification was 50%, the specificity for the test was 100%. PPV and NPV were 100% and 93%, respectively. 13C-MTBT had the sensitivity of 42% and the specificity of 99%. PPV and NPV for the breath test were of 83% and 92%, respectively. No statistically significant discrepancy between the values obtained was found. Although the 72-hour fecal fat quantification remains the gold standard in detecting EPI, both of the methods that had been investigated were shown to be comparable regarding sensitivity, specificity, PPV and NPV in assessing pancreas exocrine sufficiency in children with CP. Due to the easier execution of the breath test, both for the patient and for medical personnel, its importance may increase.

  20. Nissen fundoplication for gastroesophageal reflux: No deterioration of gastric emptying measured by 13C-acetate breath test

    Directory of Open Access Journals (Sweden)

    Tadao Okada

    2011-01-01

    Full Text Available Aim: To study the gastric emptying 30 days after laparoscopic Nissen fundoplication (NF in gastroesophageal reflux. Materials and Methods: Three patients were evaluated with 13 C-acetate breath test (ABT performed pre and post-NF. The liquid test meal consisted of Racol TM mixed with 13 C-acetate. Results: In the patient without neurological impairment (NI, the preoperative t 1/2 ex and t lag were 0.900 and 0.510 hours, respectively. The postoperative t 1/2 ex and t lag were 0.959 and 0.586 hours, respectively. In one patient with NI, the preoperative t 1/2 ex and t lag were 1.828 and 1.092 hours, respectively. The postoperative t 1/2 ex and t lag were 2.081 and 1.025 hours, respectively. In the other patient with NI, the preoperative t 1/2 ex and t lag were 2.110 and 0.980 hours, respectively. The postoperative t 1/2 ex and t lag were 1.118 and 0.415 hours, respectively. Conclusions: Our findings suggest that 13 C-ABT parameters did not worsen in any of the children after laparoscopic NF.

  1. Excretory nitrogen metabolism and defence against ammonia toxicity in air-breathing fishes.

    Science.gov (United States)

    Chew, S F; Ip, Y K

    2014-03-01

    With the development of air-breathing capabilities, some fishes can emerge from water, make excursions onto land or even burrow into mud during droughts. Air-breathing fishes have modified gill morphology and morphometry and accessory breathing organs, which would tend to reduce branchial ammonia excretion. As ammonia is toxic, air-breathing fishes, especially amphibious ones, are equipped with various strategies to ameliorate ammonia toxicity during emersion or ammonia exposure. These strategies can be categorized into (1) enhancement of ammonia excretion and reduction of ammonia entry, (2) conversion of ammonia to a less toxic product for accumulation and subsequent excretion, (3) reduction of ammonia production and avoidance of ammonia accumulation and (4) tolerance of ammonia at cellular and tissue levels. Active ammonia excretion, operating in conjunction with lowering of ambient pH and reduction in branchial and cutaneous NH₃ permeability, is theoretically the most effective strategy to maintain low internal ammonia concentrations. NH₃ volatilization involves the alkalization of certain epithelial surfaces and requires mechanisms to prevent NH₃ back flux. Urea synthesis is an energy-intensive process and hence uncommon among air-breathing teleosts. Aestivating African lungfishes detoxify ammonia to urea and the accumulated urea is excreted following arousal. Reduction in ammonia production is achieved in some air-breathing fishes through suppression of amino acid catabolism and proteolysis, or through partial amino acid catabolism leading to alanine formation. Others can slow down ammonia accumulation through increased glutamine synthesis in the liver and muscle. Yet, some others develop high tolerance of ammonia at cellular and tissue levels, including tissues in the brain. In summary, the responses of air-breathing fishes to ameliorate ammonia toxicity are many and varied, determined by the behaviour of the species and the nature of the environment in

  2. Breath 14CO2 after intravenous administration of [14C]aminopyrine in liver diseases

    International Nuclear Information System (INIS)

    Pauwels, S.; Geubel, A.P.; Dive, C.; Beckers, C.

    1982-01-01

    The determination of of 14 CO2 in breath after oral administration of [ 14 C]aminopyrine has been proposed as a quantitative liver function test. In order to shorten the procedure and avoid misinterpretations related to variable rates of intestinal absorption, the [ 14 C]aminopyrine breath test (ABT) was performed after intravenous administration of [ 14 C]aminopyrine in 21 controls and 89 patients with biopsy-proven liver disease. The specific activity of the first hour sample corrected for body weight (SA1) was the most discriminant expression of breath data. The SA1 value, expressed as the percentage of the administered dose, was 0.86 +/- 0.1% (mean +/- SD) in controls and significantly less in patients (0.46 +/- 0.31%). Low values were observed in patients with untreated chronic active hepatitis (0.16 +/- 0.13%), alcoholic cirrhosis (0.2 +/ 0.15%0, and untreated postnecrotic cirrhosis (0.47 +/- 0.17%). In contrast, normal values were obtained in chronic persistent hepatitis (0.86 +/- 0.13%) and 58% of noncirrhotic alcoholic liver diseases (0.83 +/- 0.27%). The results of duplicate studies were reproducible and SA1 correlated with other conventional liver function tests, including 45-min BSP retention. Among these, ABT was the most sensitive screening test for the presence of cirrhosis, especially in alcoholic patients, where it allowed a sharp distinction between cirrhotic and noncirrhotic cases. The results obtained in chronic hepatitis suggested that ABT may provide a reliable index of the activity of the disease. In our hands, intravenous ABT, performed over a 1-hr period, was a fast, sensitive, and discriminant liver function test

  3. Mitochondrial citrulline synthesis from ammonia and glutamine in the liver of ureogenic air-breathing catfish, Clarias batrachus (Linnaeus).

    Science.gov (United States)

    Kharbuli, Zaiba Y; Biswas, Kuheli; Saha, Nirmalendu

    2007-12-01

    The possible synthesis of citrulline, a rate limiting step for urea synthesis via the ornithine-urea cycle (OUC) in teleosts was tested both in the presence of ammonia and glutamine as nitrogen-donating substrates by the isolated liver mitochondria of ureogenic air-breathing walking catfish, C. batrachus. Both ammonia and glutamine could be used as nitrogen-donating substrates for the synthesis of citrulline by the isolated liver mitochondria, since the rate of citrulline synthesis was almost equal in presence of both the substrates. The citrulline synthesis by the isolated liver mitochondria requires succinate at a concentration of 0.1 mM as an energy source, and also requires the involvement of intramitochondrial carbonic anhydrase activity for supplying HCO3 as another substrate for citrulline synthesis. The rate of citrulline synthesis was further stimulated significantly by the isolated liver mitochondria of the fish after pre-exposure to 25 mM NH4Cl for 7 days. Due to possessing this biochemical adaptational strategy leading to the amelioration of ammonia toxicity mainly by channeling ammonia directly and/or via the formation of glutamine to the OUC, this air-breathing catfish could succeed in surviving in high external ammonia, which it faces in its natural habitat in certain seasons of the year.

  4. Phosphorus effect on the uptake, translocation and accumulation of the 14C-urea in orchard grass (Dactylis glomerata L.)

    International Nuclear Information System (INIS)

    Panak, H.; Nowak, G.; Nowak, J.; Akademia Rolniczo-Technicza, Olsztyn

    1981-01-01

    The effect of different phosphorus supplies on the uptake, translocation and accumulation of 14 C-urea by orchard grass was investigated. Phosphorus starvation inhibits the uptake, translocation and accumulation of the carbon of urea similarly to the nitrogen of urea. As compared with the uptake process the reduction of the accumulation is much more effected by the inhibition of the carbon translocation from roots to the aboveground parts. Lack of phosphorus also decreases the incorporation of the 14 C of urea into high-molecular compounds. The effect of phosphorus deficit on the accumulation of 14 C-urea increases with time of starvation. (orig.)

  5. Hyperpolarized 13C Urea Relaxation Mechanism Reveals Renal Changes in Diabetic Nephropathy

    DEFF Research Database (Denmark)

    Laustsen, Christoffer; Stokholm Nørlinger, Thomas; Christoffer Hansen, David

    2016-01-01

    Purpose: Our aim was to assess a novel 13C radial fast spin echo golden ratio single shot method for interrogating early renal changes in the diabetic kidney, using hyperpolarized (HP) [13C,15N2]urea as a T2 relaxation based contrast bio-probe. Methods: A novel HP 13C MR contrast experiment...... saturation level and the relaxation times were observed in the healthy controls. Conclusion: HP [13C,15N2]urea apparent T2 mapping may be a useful for interrogating local renal pO2 status and renal tissue alterations....

  6. Breathing air trailer acceptance test report

    International Nuclear Information System (INIS)

    Kostelnik, A.J.

    1996-01-01

    This Acceptance Test Report documents compliance with the requirements of specification WHC-S-0251, Rev.0 and ECNs 613530 and 606113. The equipment was tested according to WHC-SD-WM-ATP-104. The equipment tested is a Breathing Air Supply Trailer purchased as a design and fabrication procurement activity. The ATP was written by the Seller and was performed by the Seller with representatives of the Westinghouse Hanford Company witnessing portions of the test at the Seller's location

  7. Investigating tumor perfusion and metabolism using multiple hyperpolarized 13C compounds: HP001, pyruvate and urea

    DEFF Research Database (Denmark)

    von Morze, Cornelius; Larson, Peder E.Z.; Hu, Simon

    2012-01-01

    The metabolically inactive hyperpolarized agents HP001 (bis-1,1-(hydroxymethyl)-[1-13C]cyclopropane-d8) and urea enable a new type of perfusion magnetic resonance imaging based on a direct signal source that is background-free. The addition of perfusion information to metabolic information obtained...... (T1=95 s ex vivo, 32 s in vivo at 3 T) using a pulse sequence with balanced steady-state free precession and ramped flip angle over time for efficient utilization of the hyperpolarized magnetization and three-dimensional echo-planar spectroscopic imaging of urea copolarized with [1-13C...... of separate dynamic HP001 imaging and copolarized pyruvate/urea imaging were compared. A strong and significant correlation (R=0.73, P=.02) detected between the urea and HP001 data confirmed the value of copolarizing urea with pyruvate for simultaneous assessment of perfusion and metabolism....

  8. Cells for bioartificial liver devices: the human hepatoma-derived cell line C3A produces urea but does not detoxify ammonia.

    Science.gov (United States)

    Mavri-Damelin, Demetra; Damelin, Leonard H; Eaton, Simon; Rees, Myrddin; Selden, Clare; Hodgson, Humphrey J F

    2008-02-15

    Extrahepatic bioartificial liver devices should provide an intact urea cycle to detoxify ammonia. The C3A cell line, a subclone of the hepatoma-derived HepG2 cell line, is currently used in this context as it produces urea, and this has been assumed to be reflective of ammonia detoxification via a functional urea cycle. However, based on our previous findings of perturbed urea-cycle function in the non-urea producing HepG2 cell line, we hypothesized that the urea produced by C3A cells was via a urea cycle-independent mechanism, namely, due to arginase II activity, and therefore would not detoxify ammonia. Urea was quantified using (15)N-ammonium chloride metabolic labelling with gas chromatography-mass spectrometry. Gene expression was determined by real-time reverse transcriptase-PCR, protein expression by western blotting, and functional activities with radiolabelling enzyme assays. Arginase inhibition studies used N(omega)-hydroxy-nor-L-arginine. Urea was detected in C3A conditioned medium; however, (15)N-ammonium chloride-labelling indicated that (15)N-ammonia was not incorporated into (15)N-labelled urea. Further, gene expression of two urea cycle genes, ornithine transcarbamylase and arginase I, were completely absent. In contrast, arginase II mRNA and protein was expressed at high levels in C3A cells and was inhibited by N(omega)-hydroxy-nor-L-arginine, which prevented urea production, thereby indicating a urea cycle-independent pathway. The urea cycle is non-functional in C3A cells, and their urea production is solely due to the presence of arginase II, which therefore cannot provide ammonia detoxification in a bioartificial liver system. This emphasizes the continued requirement for developing a component capable of a full repertoire of liver function. (c) 2007 Wiley Periodicals, Inc.

  9. Identification of risk factors for pancreatic exocrine insufficiency after pancreaticoduodenectomy using a 13C-labeled mixed triglyceride breath test.

    Science.gov (United States)

    Hirono, Seiko; Murakami, Yoshiaki; Tani, Masaji; Kawai, Manabu; Okada, Ken-ichi; Uemura, Kenichiro; Sudo, Takeshi; Hashimoto, Yasushi; Nakagawa, Naoya; Kondo, Naru; Yamaue, Hiroki

    2015-02-01

    There are only a few reports concerning long-term exocrine function after pancreaticoduodenectomy (PD), although the number of long-term survivors has increased. We assessed pancreatic exocrine function after PD in 189 patients to identify risk factors for pancreatic exocrine insufficiency. We evaluated patients' exocrine function by using the (13)C-labeled mixed triglyceride breath test, a noninvasive test feasible in outpatient service units. The present study included 99 patients that underwent pancreaticojejunostomy (PJ) at Wakayama Medical University Hospital and 90 patients that underwent pancreaticogastrostomy (PG) at Hiroshima University Hospital, the standard reconstruction techniques during PD at the respective hospitals. We also analyzed long-term morphological changes of remnant pancreas by computed tomography (main pancreatic duct dilation and parenchymal atrophy), nutritional status, and endocrine function. Independent risk factors for exocrine insufficiency after PD include hard pancreas (P = 0.003, odds ratio; 3.157) and PG reconstruction (P = 0.040, odds ratio; 2.321). Breath test results correlated significantly with post-operative morphological changes, nutritional status, and endocrine function. Atrophic changes of the remnant pancreas in the PG group were more severe than those in the PJ group. Furthermore, for patients with a soft pancreas, postoperative body weight changes, prognostic nutritional index, serum total protein levels as well as exocrine test were worse in the PG group, compared with the PJ group. Our results showed that PJ reconstruction might be superior to PG during PD, from the viewpoint of long-term pancreatic exocrine function, although further prospective studies are needed.

  10. Metabolism of 14C-labelled urea in conventional, germ-free and mono-associated rats

    International Nuclear Information System (INIS)

    Juhr, N.C.; Franke, J.

    1987-01-01

    This report deals with the utilization of 14 C-labelled urea in conventional, defined associated and germ-free rats. With conventional animals 71.44% of the administered 14 C dose can be demonstrated in the exhaled air, 0.47% in organs and 27.35% in the urine. 1.04% were found in the intestinal and fecal contents. Animals mono-associated with Proteus mirabilis have nearly the same utilization rate (59.15, 0.34, 35.98, 2% resp.). In germ-free animals 1.21% of the activity appeared in the exhaled air and showed a small part of non-enzymatic hydrolysis of urea. The excretion of 97.70% in the urine shows, that urea is absorbed from the intestine in germ-free animals. (author)

  11. Deposits from Creams Containing 20% (w/w) Urea and Suppression of Crystallization (Part 2): Novel Analytical Methods of Urea Accumulated in the Stratum Corneum by Tape stripping and Colorimetry.

    Science.gov (United States)

    Goto, Norio; Morita, Yutaka; Terada, Katsuhide

    2016-01-01

    The transfer of urea from a urea formulation to the stratum corneum varies with the formulation base and form, and impacts the formulation's therapeutic effect. Consequently, determining the amount of urea transferred is essential for developing efficient formulations. This study assessed a simple method for measuring the amount of urea accumulated in the stratum corneum. Conventional methods rely on labeling urea used in the formulation with radiocarbon ((14)C) or other radioactive isotopes (RIs), retrieving the transferred urea from the stratum corneum by tape stripping, then quantitating the urea. The handling and use of RIs, however, is subject to legal regulation and can only be performed in sanctioned facilities, so methods employing RIs are neither simple nor convenient. We therefore developed a non-radiolabel method "tape stripping-colorimetry (T-C)" that combines tape stripping with colorimetry (urease-glutamate dehydrogenase (GLDH)) for the quantitative measurement of urea. Urea in the stratum corneum is collected by tape stripping and measured using urease-GLDH, which is commonly used to measure urea nitrogen in blood tests. The results indicate that accurate urea measurement by the T-C method requires the application of 1400 mg (on hairless rats) of a 20% urea solution on a 50 cm(2) (5×10 cm) area. Further, we determined the amount of urea accumulated in the stratum corneum using formulations with different urea concentrations, and the time course of urea accumulation from formulations differing in the rate of urea crystallization. We demonstrate that the T-C method is simple and convenient, with no need for (14)C or other RIs.

  12. Estimate of production of gaseous nitrogen in the human body based on (15)N analysis of breath N2 after administration of [(15)N2]urea.

    Science.gov (United States)

    Junghans, Peter

    2013-01-01

    After oral administration of [(15)N2]urea (1.5 mmol, 95 atom% (15)N), we found that breath N2 was significantly (15)N-labelled. The result suggests that molecular nitrogen in breath must be partly produced endogenously. Based on a metabolic model, the endogenous N2 production was estimated to be 0.40±0.25 mmol kg(-1) d(-1) or 2.9±1.8 % of the total (urinary and faecal) N excretion in fasted healthy subjects (n=4). In patients infected with Helicobacter pylori (n=5), the endogenous N2 production was increased to 1.24±0.59 mmol kg(-1) d(-1) or 9.0±4.3 % of the total N excretion compared to the healthy controls (pexchange measurements may be affected by endogenously produced nitrogen, especially in metabolic situations with elevated nitrosation, for instance in oxidative and nitrosative stress-related diseases such as H. pylori infections.

  13. Clinical value of 13C-UBT diagnosing infection of the Hp

    International Nuclear Information System (INIS)

    Xu Changde; Chen Shaoliang; Liu Wenguan

    2004-01-01

    100 dyspeptic patients are performed an endoscopy with biopsy for histology, rapid urease test, 13 C-urea breath test( 13 C-UBT) and ASSURE TM Hp rapid Test(HpRT). Patients are considered to be infected if both histology and biopsies yield positive results, and not infected when both tests are negative. The pathology and persons responsible for endoscopy, urease test and 13 C-UBT are unaware of the results from the other diagnostic methods. The 13 C-UBT has the following results: sensitivity 96% ,specificity 95%; rapid urease test has the following results: sensitivity 79%, specificity 76%; HpRT has the following results: sensitivity 86%, specificity 88%. 13 C-UBT provides excellent sensitivity and specificity for the diagnosis of Hp. Pylori infected Hp, it can be the first choice for detecting the infection of the Hp. (authors)

  14. Leaching of dieldrin, permethrin, phenyl urea and 4-CL phenyl urea pesticides from soil

    International Nuclear Information System (INIS)

    Onal, G.

    1978-01-01

    Leaching of four 14 C-labelled pesticides (dieldrin, permethrin, phenyl urea and 4-Cl phenyl urea) were investigated. It was found that dieldrin and permethrin were not leached from soil but adsorbed by the soil; phenyl urea and 4-CL phenyl urea were leached to a 7.5 cm depth

  15. Redox Thermodynamics of Cytochromes c Subjected to Urea Induced Unfolding

    NARCIS (Netherlands)

    Monari, S.; Ranieri, A.; Di Rocco, G.; van der Zwan, G.; Peressini, S.; Tavagnacco, C.; Millo, D.; Borsari, M.

    2009-01-01

    The thermodynamics of the electron transfer (ET) process for beef heart and yeast cytochromes c and the Lys72Ala/Lys73Ala/Lys79Ala mutant of the latter species subjected to progressive urea-induced unfolding was determined electrochemically. The results indicate the presence of at least three

  16. (13)C enrichment of the CO2 in breast milk and in the breath is rapidly modified by changes in the (13)C content of the diet.

    Science.gov (United States)

    Villalpando, Salvador; Del Prado, Martha; Cienfuego, Edith; Morales, Pedro

    2014-01-01

    C4 plants (e.g. corn and sugar cane) have greater (13)C enrichment than C3 plants (e.g. wheat and sugar beet). To assess whether (13)C enrichment of CO2 in the breath and breast milk of women on diets based on C3 and C4 foods changes from one diet to the other. Six breast-feeding women were studied at 5-6 months postpartum. They ate a controlled C4 diet on days 1 and 2 followed by a C3 diet on days 3 and 4. Diet duplicates, breast milk on days 2 and 4 and hourly breath samples were collected over 4 days. (13)C enrichment was measured by isotope-ratio mass spectrometry. Values of δ(13)C were calculated from the international PDBV standard (δ(13)CPDBV). Differences between means were compared by paired t test or t test for repeated measurements. δ(13)CPDBV values were significantly higher in the C4 diet than in the C3 diet composites (p value was greater on days 1 and 2 (range -15.4 to -13.2, respectively) and declined on days 3 and 4 (range -20.0 to -21.8, respectively, p value in the breath and breast milk fractions, which diminish rapidly on a C3 diet. Further studies focusing on individual nutrients are warranted.

  17. Effect of alcohol consumption on the liver detoxication capacity as measured by [13C2]aminopyrine and L-[1-13C]phenylalanine breath tests.

    Science.gov (United States)

    Wutzke, Klaus D; Wigger, Marianne

    2009-09-01

    The aim of this study was to investigate the hepatic microsomal and cytosolic functions by using the 13CO2 breath test in healthy subjects either before or after consumption of red wine. Twelve adults received [13C2]aminopyrine and L-[1-13C]phenylalanine together with a standardised dinner. Expired air samples were taken over 6 h. After a wash-out period, the subjects consumed 0.4 ml ethanol per kg per day together with dinner over a 7.5-day period on average. Thereafter, 13C-tracer administration was repeated under identical conditions. The 13CO2 enrichments were measured by isotope ratio mass spectrometry. The mean cumulative percentage 13C-dose recovery after administration of [13C2]aminopyrine and L-[1-13C]phenylalanine either without or with red wine consumption amounted to 17.0+/-4.4 vs. 14.7+/-3.1% (p=0.170) and 14.0+/-2.8 vs. 11.5+/-3.9% (p=0.084), respectively. Moderate alcohol consumption does not induce significant short-term changes of the microsomal and the cytosolic function of the human liver in healthy subjects.

  18. Oxidation of linoleic and palmitic acid in pre-hibernating and hibernating common noctule bats revealed by 13C breath testing.

    Science.gov (United States)

    Rosner, Elisabeth; Voigt, Christian C

    2018-02-19

    Mammals fuel hibernation by oxidizing saturated and unsaturated fatty acids from triacylglycerols in adipocytes, yet the relative importance of these two categories as an oxidative fuel may change during hibernation. We studied the selective use of fatty acids as an oxidative fuel in noctule bats ( Nyctalus noctula ). Pre-hibernating noctule bats that were fed 13 C-enriched linoleic acid (LA) showed 12 times higher tracer oxidation rates compared with conspecifics fed 13 C-enriched palmitic acid (PA). After this experiment, we supplemented the diet of bats with the same fatty acids on five subsequent days to enrich their fat depots with the respective tracer. We then compared the excess 13 C enrichment (excess atom percentage, APE) in breath of bats for torpor and arousal events during early and late hibernation. We observed higher APE values in breath of bats fed 13 C-enriched LA than in bats fed 13 C-enriched PA for both states (torpor and arousal), and also for both periods. Thus, hibernating bats selectively oxidized endogenous LA instead of PA, probably because of faster transportation rates of polyunsaturated fatty acids compared with saturated fatty acids. We did not observe changes in APE values in the breath of torpid animals between early and late hibernation. Skin temperature of torpid animals increased by 0.7°C between early and late hibernation in bats fed PA, whereas it decreased by -0.8°C in bats fed LA, highlighting that endogenous LA may fulfil two functions when available in excess: serving as an oxidative fuel and supporting cell membrane functionality. © 2018. Published by The Company of Biologists Ltd.

  19. Peak {sup 14}CO{sub 2} excretion, symptoms and eradication of H.Pylori (HP) in patients with duodenal ulcer (DU)

    Energy Technology Data Exchange (ETDEWEB)

    Batholomeusz, F.D.L.; Bellon, M. [Royal Adelaide Hospital, Adelaide, SA (Australia). Department of Nuclear Medicine

    1997-12-01

    Full text: Many factors including drug efficacy, compliance and antibiotic resistance may influence HP eradication rates. The {sup 14}C urea breath test is a sensitive method of confirming HP colonisation and eradication. The aim was to study the relationships between the peak {sup 14}CO{sub 2} counts on the breath test prior to treatment, smoking and HP eradication, and to assess if persistent or recurrent symptoms implied failure of eradication. 117 patients with DU and HP colonisation proved on biopsy or rapid urease test who underwent {sup 14}C urea breath tests at least one month after eradication treatment was ceased were studied (69 male, 48 female, mean age 41, range 26-87 y). Questionnaire assessment of treatment regimen, smoking history and dyspeptic symptoms was made at the time of the breath test. A sub-group of 43 patients who had pre- and post-treatment breath tests was studied to assess if high peak {sup 14}CO{sub 2} counts on the pre-treatment breath test related to treatment success. The mean peak initial {sup 14}CO{sub 2} excretion in those who were treated successfully was 4187 (+ 472) counts/min and for failures 4817 (+739) counts/min (p 0.24). Dyspeptic symptoms were present in 36% of patients treated successfully and 37% where treatment failed. The eradication rate for the 56 smokers was 75 per cent, and the 61 non-smokers 83%. (p>0.2) High {sup 14}CO{sub 2} excretion on the initial {sup 14}C urea breath test and smoking are not associated with a significantly lower rate of HP eradication and the presence of dyspepsia is not a good indicator of persistent infection

  20. Correlation between dietary nitrogen, level of plasma urea and urea excretion in urine of buffalo calves

    International Nuclear Information System (INIS)

    Verma, D.N.; Singh, U.B.

    1978-01-01

    Two experiments were conducted with 6 male buffalo calves of Murrah breed, aged 1.5 years, to determine whether blood urea nitrogen and urea excretion in urine were associated with protein intake. The animals were fed different amounts of crude protein in their diet. The levels of urea-N in the blood, excretion of 14 C from urea and urea-N in the urine were estimated. Close relationships were observed between nitrogen intake, blood urea nitrogen and urea excretion in the urine. The observations indicated that blood urea-N and urea excretion in urine could be quantitated with the protein intake. (author)

  1. [Breath tests in children with suspected lactose intolerance].

    Science.gov (United States)

    Parra, P Ángela; Furió, C Simone; Arancibia, A Gabriel

    2015-01-01

    Up to 70% of the world population is lactose intolerance. However, there are no epidemiological studies among Chilean pediatric population affected by this condition. Clinical characterization of a series of children who underwent the lactose intolerance breath test for lactose intolerance study, establishing intolerance and malabsorption frequencies, the most frequent symptoms, and test performance depending on the origin. Patients under 18 years old who took the lactose intolerance breath test in the Gastroenterology Laboratory of the Catholic University of Chile, and who were admitted due to clinically suspected lactose intolerance. Malabsorption was considered when there was as an increase of ≥20ppm above the baseline (H2) or ≥34ppm of H2 and methane (CH4) combined. Intolerance was considered when the above was associated with a symptom intensity score ≥7 during registration. The analysis included194 patients aged 1 to17 years of age. Of these, 102 (53%) presented with malabsorption, and 53 (27%) were intolerant. The frequency of lactose intolerance varied from 7.1 to 45.4%, and it occurred more frequently at older ages. The most common reported symptoms were abdominal pain, bloating and rumbling. Lactose malabsorption and intolerance can be investigated from the first years of life using the lactose breath test plus a symptom questionnaire. An increase in the frequency of intolerance with age, and a greater number of positive tests, if they were requested by a gastroenterologist, were observed. Copyright © 2015 Sociedad Chilena de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  2. Appraisal of the 14C-glycocholate acid test with special reference to the measurement of faecal 14C excretion

    International Nuclear Information System (INIS)

    Scarpello, J.H.B.; Sladen, G.E.

    1977-01-01

    The 14 C-glycocholate test, including the measurement of marker corrected faecal 14 C, has been assessed in the following groups of subjects: normal controls (18), patients with diarrhoea not attributable to altered bile acid metabolism (21), patients with diverticula of the small intestine (12), patients with previous resection of ileum and often proximal colon (34), and established ileostomists (10). Patients with diverticular disease had increased breath 14 CO 2 excretion, but normal faecal excretion of 14 C, and this test was more frequently abnormal than the Schilling test. Ileostomists excreted increased amounts of faecal 14 C, even when the ileum was intact and apparently normal. The pattern after resection was complex. Breath 14 C output was normal if the ileal resection was less than 25 cm in length, although some of these patients had increased faecal 14 C excretion if, in addition, at least 15 cm of proximal colon had been resected or by-passed. Longer ileal resections were associated with increased breath and/or faecal 14 C excretion, depending in part on the length of colon resected or by-passed and the 24 hour faecal volume. Fewer than half these patients had both increased breath and faecal excretion of isotope and faecal 14 C alone was occasionally normal with an ileal resection of 50 cm or more. The 14 C-glycocholate test was more frequently abnormal than the Schilling test in this group. The use of faecal marker correction had only a minor impact on the results. These data suggest that, in patients with ileal resection, faecal 14 C, like faecal weight, is determined by the extent of colonic resection as well as by the amount of ileum resected. (author)

  3. Prevalence of abnormal lactose breath hydrogen tests in children with functional abdominal pain.

    Science.gov (United States)

    Garg, Neha; Basu, Srikanta; Singh, Preeti; Kumar, Ruchika; Sharma, Lokesh; Kumar, Praveen

    2017-05-01

    The study was undertaken to determine the prevalence of abnormal lactose breath hydrogen test in children with non-organic chronic abdominal pain. Children with chronic abdominal pain were examined and investigated for organic causes. All children without a known organic cause underwent lactose and glucose breath hydrogen test. After a standard dose of 2 g/kg of lactose to a maximum of 50 g, hydrogen in breath was measured at 15 min intervals for 3 h. A rise of 20 ppm above baseline was considered suggestive of lactose malabsorption. Of 108 children screened, organic causes were found in 46 children. Sixty-two patients without any organic cause underwent hydrogen breath test. Lactose hydrogen breath test (HBT) was positive in 36 of 62 (58%), while 11 (17%) had positive HBT with glucose suggestive of small intestinal bacterial overgrowth (SIBO). Twenty out of 34 (59%) improved on lactose free diet while 8 out of 11 (72%) children of SIBO improved on antibiotics. Lactose malabsorption was seen in 58% of children with non-organic chronic abdominal pain.

  4. Fast-starting for a breath: Air breathing in Hoplosternum littorale

    DEFF Research Database (Denmark)

    Domenici, Paolo; Norin, Tommy; Bushnell, Peter G.

    by the fall of a prey item on the water surface, and in tapping motions of goldfish, a behaviour that was interpreted to be food-related. Little is known about C-starts being used outside the context of escaping or feeding. Here, we test the hypothesis that air-breathing fish may use C-starts when gulping air...

  5. Advantages and disadvantages of current diagnostic tests for the detection of Helicobacter pylori.

    Science.gov (United States)

    Mégraud, F

    1996-01-01

    Current tests used to detect Helicobacter pylori are either invasive (histological detection, culture, the polymerase chain reaction (PCR), smear examination) or non-invasive (serology, 13C-urea breath test). These tests vary in their sensitivity and specificity, and the choice of test will depend on the situation, for example, whether the test is to detect infection or the success of eradication treatment. The accuracy of histological tests depends, to a large degree, on the expertise of the pathologist, while the accuracy of culture can depend on the conditions in which the specimen is transported and processed. When performed under optimal conditions, both techniques give very good results. The PCR test has similar sensitivity and specificity to histological and culture tests but a strict protocol must be followed to avoid contamination with H. pylori DNA. The rapid urease test (with a reading taken 1 hour later) is suitable for diagnosis before treatment but its sensitivity decreases after treatment. Smear examination has limited sensitivity. The urea breath test and serology (specific IgG detected by enzyme-linked immunosorbent assay with purified antigens) have sensitivities close to those using the best of the biopsy methods. Other points to consider when selecting a test are its availability, the rapidity of the results (which can range from a few minutes to 2 weeks), possibilities for retrospective analysis, quantification and the detection of pathogenic properties, the globality of certain tests that present an overall picture of the stomach, thus avoiding errors in sampling, and the cost of the test. Important added value can be gained from certain tests: histology allows evaluation of the status of the mucosa, culture allows strain typing and tests for antibiotic susceptibility, and the breath test can confirm successful eradication without endoscopy. When the diagnostic tests are performed correctly, most of them are highly accurate.

  6. A novel one-step Helicobacter pylori saliva antigen test.

    Science.gov (United States)

    Yang, Bi-Ling; Yeh, Chun; Kwong, Wei-Gang; Lee, Shou-Dong

    2015-02-01

    A rapid, reliable, and sufficiently accurate test for diagnosing Helicobacter pylori infection is required for screening dyspeptic patients before a referral for endoscopy. The purpose of this article is two-fold: first, to evaluate the accuracy of a one-step H. pylori saliva antigen (HPS) test; and second, to compare noninvasive and invasive H. pylori tests in Taiwanese population. A total of 104 consecutive dyspeptic patients admitted for gastroenterology into the outpatient department underwent a one-step HPS test, rapid urease test, histology, and (13)C-urea breath test (13)C-UBT (proto C-13 urea kit). The accuracy of the HPS test was compared with a gold standard defined by at least two positive H. pylori test results from three H. pylori tests (histology, rapid urease test, and (13)C-UBT). The 104 patients eligible for analysis (mean age: 58 years, range 22-87 years), 21 (20%) were gold standard positive. Among them, the positive of the one-step H. pylori saliva Ag test, rapid urease test, (13)C-UBT, histology were (52; 50%), (17; 16%), (27; 25%) and (22; 21%) respectively. The sensitivity and specificity of the HPS tests, rapid urease test, (13)C-UBTs, and histology were 71.43% and 55.42%, 76.19% and 98.80%, 100% and 92.77%, and 85.71% and 95.18%, respectively, relative to the gold standard. The one-step HPS test exhibited a sensitivity of 71.43%, nearly equivalent to that of the rapid urea test. The one-step HPS test exhibited a high sensitivity and low specificity compared with the other tests, indicating that it is not sufficiently accurate for use in a clinical setting for diagnosing H. pylori infection. However, the test is simple to use (requiring only a saliva sample), inexpensive, and noninvasive in its application, and thus appealing for use in population-based prevalence surveys of the epidemiology of H. pylori infection. Copyright © 2014. Published by Elsevier Taiwan.

  7. 13C-sodium acetate breath test for evaluation of gastric emptying times in dogs with gastric dilatation-volvulus.

    Science.gov (United States)

    Schmitz, S; Jansen, N; Failing, K; Neiger, R

    2013-01-01

    The aim of the study was to assess solid phase gastric emptying via non-invasive 13C-sodium acetate breath test in large breed dogs with or without gastric dilatation-volvulus (GDV). Dogs were recruited into one of the following groups: group 1 = healthy large breed dogs with no history of GDV, group 2 = dogs that underwent elective abdominal surgery for reasons unrelated to the gastrointestinal tract, and group 3 = dogs that underwent laparotomy and gastropexy to correct GDV. The dogs were fed a test meal containing 100 mg 13C-sodium acetate (for group 2 and 3, this was gastric emptying times were calculated and compared between groups. Gastric emptying times were significantly prolonged in dogs undergoing surgery (group 2) compared to group 1 and 3. Also, gastric emptying times of dogs with GDV were significantly prolonged compared to controls, but not to the same extent as dogs in group 2. There was a significant effect of abdominal surgery on gastric emptying times. Surprisingly, dogs after GDV surgery and gastropexy had shorter gastric emptying times than dogs undergoing laparotomy for reasons other than GDV, but still prolonged compared to healthy controls. The reason for these differences requires further study.

  8. Determination of urea kinetics by isotope dilution with [C-13]urea and gas chromatography isotope ratio mass spectrometry (GC-IRMS) analysis

    NARCIS (Netherlands)

    Kloppenburg, Wybe; Wolthers, BG; Stellaard, F; Elzinga, H; Tepper, T; deJong, PE; Huisman, RM

    1. Stable urea isotopes can be used to study urea kinetics in humans, The use of stable urea isotopes far studying urea kinetic parameters in humans on a large scale is hampered by the high costs of the labelled material, We devised a urea dilution for measurement of the distribution volume,

  9. System for routine testing of self-contained and airline breathing equipment

    Energy Technology Data Exchange (ETDEWEB)

    McDermott, H.J.; Hermens, G.A.

    1980-07-01

    A system for routine testing of self-contained and airline breathing equipment, developed by Shell Oil Co., for testing breathing equipment at one of its refineries, consists of an 80 psig air supply for airline respirators; a 500-2100 psig air supply for self-contained units; a regulator test system which uses a mannequin head that simulates human inhalation and which tests the ability of the regulator to keep the mask interior at the correct positive pressure; and an exhalation valve test system which identifies a leaky or sticking valve. The testing system has been in use for about 30 mo and has led to increased acceptance of respiratory protective equipment by workers.

  10. Fe{sub 3}C/Fe nanoparticles with urea: Synthesis, structure and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaobai [College of Chemistry, Jilin University, Changchun, 130012 (China); School of Chemical and Pharmaceutical Engineering, Jilin Institute of Chemical Technology, Jilin, 132022 (China); Zhang, Daguang [Department of Orthopaedic Surgery, the First Hospital of Jilin University, Changchun, 130021 China (China); Ren, Xiaozhen; Gao, Jiajia [College of Chemistry, Jilin University, Changchun, 130012 (China); Han, Yu [Department of Chemistry, College of Science, Yanbian University, Yanji, 133002 China (China); Chen, Xiaodong [College of Chemistry, Jilin University, Changchun, 130012 (China); Shi, Zhan [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012 (China); Yang, Hua [College of Chemistry, Jilin University, Changchun, 130012 (China)

    2016-12-15

    Fe{sub 3}C/Fe nanocomposites were synthesized by a sol–gel method. Using urea as carbon source and reduce agent in the reaction process. The CTAB works as the surfactant and the bromine contained in CTAB plays a catalytic role. Appropriate choices of the amount of urea and CTAB, reaction temperature and time are very important to obtain high-quality of products. Above 650 °C, the precursor gel turned into the nanocomposites composed of iron carbide and iron. Their structures and magnetic properties are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The possible formation mechanism of as-prepared nanostructures is discussed. - Highlights: • The Fe{sub 3}C/Fe composites were synthetized by sol–gel method. • Their structure, magnetic properties are researched by XRD, VSM and TEM. • The possible formation mechanisms of the composites is discussed.

  11. Appraisal of the /sup 14/C-glycocholate acid test with special reference to the measurement of faecal /sup 14/C excretion

    Energy Technology Data Exchange (ETDEWEB)

    Scarpello, J H.B.; Sladen, G E [Royal Hospital, Sheffield (UK). Academic Div. of Medicine

    1977-09-01

    The /sup 14/C-glycocholate test, including the measurement of marker corrected faecal /sup 14/C, has been assessed in the following groups of subjects: normal controls (18), patients with diarrhoea not attributable to altered bile acid metabolism (21), patients with diverticula of the small intestine (12), patients with previous resection of ileum and often proximal colon (34), and established ileostomists (10). Patients with diverticular disease had increased breath /sup 14/CO/sub 2/ excretion, but normal faecal excretion of /sup 14/C, and this test was more frequently abnormal than the Schilling test. Ileostomists excreted increased amounts of faecal /sup 14/C, even when the ileum was intact and apparently normal. The pattern after resection was complex. Breath /sup 14/C output was normal if the ileal resection was less than 25 cm in length, although some of these patients had increased faecal /sup 14/C excretion if, in addition, at least 15 cm of proximal colon had been resected or by-passed. Longer ileal resections were associated with increased breath and/or faecal /sup 14/C excretion, depending in part on the length of colon resected or by-passed and the 24 hour faecal volume. Fewer than half these patients had both increased breath and faecal excretion of isotope and faecal /sup 14/C alone was occasionally normal with an ileal resection of 50 cm or more. The /sup 14/C-glycocholate test was more frequently abnormal than the Schilling test in this group. The use of faecal marker correction had only a minor impact on the results. These data suggest that, in patients with ileal resection, faecal /sup 14/C, like faecal weight, is determined by the extent of colonic resection as well as by the amount of ileum resected.

  12. Increased accuracy of the carbon-14 D-xylose breath test in detecting small-intestinal bacterial overgrowth by correction with the gastric emptying rate

    International Nuclear Information System (INIS)

    Chang Chisen; Chen Granhum; Kao Chiahung; Wang Shyhjen; Peng Shihnen; Huang Chihkuen; Poon Sekkwong

    1995-01-01

    The aim of this study was to determine whether the accuracy of 14 C-D-xylose breath test for detecting bacterial overgrowth can be increased by correction with the gastric emptying rate of 14 C-D-xylose. Ten culture-positive patients and ten culture-negative controls were included in the study. Small-intestinal aspirates for bacteriological culture were obtained endoscopically. A liquid-phase gastric emptying study was performed simultaneously to assess the amount of 14 C-D-xylose that entered the small intestine. The results of the percentage of expired 14 CO 2 at 30 min were corrected with the amount of 14 C-D-xylose that entered the small intestine. There were six patients in the culture-positive group with a 14 CO 2 concentration above the normal limit. Three out of four patients with initially negative results using the uncorrected method proved to be positive after correction. All these three patients had prolonged gastric emptying of 14 C-D-xylose. When compared with cultures of small-intestine aspirates, the sensitivity and specificity of the uncorrected 14 C-D-xylose breath test were 60% and 90%, respectively. In contrast, the sensitivity and specificity of the corrected 14 C-D-xylose breath test improved to 90% and 100%, respectively. (orig./MG)

  13. Metabolism of urea in kids fed different levels of urea molasses diets

    International Nuclear Information System (INIS)

    Lal, M.; Singh, U.B.; Verma, D.N.

    1981-01-01

    Urea entry rates were measured in the body pool of Barbari kids using a single injection isotope dilution technique. The kids were divided into five groups (T 1 , T 2 , T 3 , T 4 and T 5 ) and they were fed different levels of urea molasses viz., 10, 25, 35, 40 and 0 percent to meet their DCP requirement along with concentrate mixture and oat hay as per A.R.C. recommendation. Urea entry rate was significantly higher (P 1 and the control group (T 5 without urea in their diets) than that of T 2 , T 3 and T 4 which were not significantly different from each other. (author)

  14. Four-sample lactose hydrogen breath test for diagnosis of lactose malabsorption in irritable bowel syndrome patients with diarrhea.

    Science.gov (United States)

    Yang, Jian-Feng; Fox, Mark; Chu, Hua; Zheng, Xia; Long, Yan-Qin; Pohl, Daniel; Fried, Michael; Dai, Ning

    2015-06-28

    To validate 4-sample lactose hydrogen breath testing (4SLHBT) compared to standard 13-sample LHBT in the clinical setting. Irritable bowel syndrome patients with diarrhea (IBS-D) and healthy volunteers (HVs) were enrolled and received a 10 g, 20 g, or 40 g dose lactose hydrogen breath test (LHBT) in a randomized, double-blinded, controlled trial. The lactase gene promoter region was sequenced. Breath samples and symptoms were acquired at baseline and every 15 min for 3 h (13 measurements). The detection rates of lactose malabsorption (LM) and lactose intolerance (LI) for a 4SLHBT that acquired four measurements at 0, 90, 120, and 180 min from the same data set were compared with the results of standard LHBT. Sixty IBS-D patients and 60 HVs were studied. The genotype in all participants was C/C-13910. LM and LI detection rates increased with lactose dose from 10 g, 20 g to 40 g in both groups (P lactose doses in both groups. Reducing the number of measurements from 13 to 4 samples did not significantly impact on the accuracy of LHBT in health and IBS-D. 4SLHBT is a valid test for assessment of LM and LI in clinical practice.

  15. DHA Concentration and Purification from the Marine Heterotrophic Microalga Crypthecodinium cohnii CCMP 316 by Winterization and Urea Complexation

    Directory of Open Access Journals (Sweden)

    Ana Mendes

    2007-01-01

    Full Text Available A simple and inexpensive procedure involving saponification and methylation in wet biomass, winterization and urea complexation in a sequential way has been developed in order to concentrate docosahexaenoic acid (DHA from Crypthecodinium cohnii CCMP 316 biomass. Different urea/fatty acid ratios and crystallization temperatures were tested in the urea complexation method. ANOVA test revealed that, in the studied range, the temperature had the most significant effect on the DHA concentration. The highest DHA fraction (99.2 % of total fatty acids was found at the urea/fatty acid ratio of 3.5 at the crystallization temperatures of 4 and 8 °C. The highest DHA recovery (49.9 % was observed at 24 °C at the urea/fatty acid ratio of 4.0, corresponding to 89.4 % DHA of total fatty acids. Considering the high proportions of DHA obtained in the non-urea complexing fractions, the current procedure was an appropriate way to concentrate and purify DHA from C. cohnii.

  16. [Separation of gamma linolenic acid from evening primrose oil with urea inclusion--orthogonal experiment of optimizing technological parameters and observation of urea inclusion compound I].

    Science.gov (United States)

    Wang, Hua; Ling, Man; Xue, Gang; Liu, Fengxia; Guo, Shuxian

    2010-05-01

    The influence on the urea inclusion compound under different conditions (allocated proportion, time of inclusion, temperature of inclusion) were studied through the orthogonal test, and theoretical reference of urea inclusion process for further optimization wound be offered. The orthogonal experiment was adopted, and microscope was used to observe the shape, aperture size of the urea inclusion compound under different technological parameters, the GC was employed to inspect the purity of GLA. The results indicated that the ratio of fatty acids and urea, inclusion of temperature, time of inclusion had great effect on urea inclusion compound. The three factors and its interactions significantly affected the purity of GLA. The results also showed that the best process was that the ratio of fatty acids and urea was 1 : 3, temperature of inclusion was--15 degrees C, time of inclusion was 24 h. Under the best condition, the purity of GLA reach up to 95.575 9%; and it is feasible to observe the shape and the amount of the urea inclusion compound to reflect and guide the urea inclusion technology.

  17. Measurement of synovial fluid volume using urea.

    Science.gov (United States)

    Kraus, V B; Stabler, T V; Kong, S Y; Varju, G; McDaniel, G

    2007-10-01

    To examine the utility of using urea concentrations for determining Synovial Fluid (SF) joint volume in effused and non-effused joints. Knee joint SF was aspirated from 159 human study participants with symptomatic osteoarthritis of at least one knee either directly (165 knees) or by lavage (110 knees). Serum was obtained immediately prior to SF aspiration. Participants were asked to rate individual knee pain, aching or stiffness. SF and serum urea levels were determined using a specific enzymatic method run on an automated CMA600 analyzer. Cell counts were performed on direct SF aspirates when volume permitted. The formula for calculating SF joint volume was as follows: V(j)=C(D)(V(I))/(C-C(D)) with V(j)=volume of SF in entire joint, C(D)=concentration of urea in diluted (lavage) SF, V(I)=volume of saline injected into joint, and C=concentration of urea in undiluted (neat) SF derived below where C=0.897(C(S)) and C(s)=concentration of urea in serum. There was an excellent correlation (r(2)=0.8588) between SF and serum urea in the direct aspirates with a ratio of 0.897 (SF/serum). Neither urea levels nor the SF/serum ratio showed any correlation with Kellgren Lawrence (KL) grade, or cell count. While urea levels increased with age there was no change in the ratio. Intraarticular SF volumes calculated for the lavaged knees ranged from 0.555 to 71.71ml with a median volume of 3.048ml. There was no correlation of SF volume to KL grade but there was a positive correlation (P=0.001) between SF volume and self-reported individual knee pain. Our urea results for direct aspirates indicate an equilibrium state between serum and SF with regard to the water fraction. This equilibrium exists regardless of disease status (KL grade), inflammation (cell count), or age, making it possible to calculate intraarticular volume of lavaged joints based upon this urea method. Most of the joint volumes we calculated fell within the previously reported range for normal knees of 0.5-4.0ml

  18. Validation of the salivary urea and creatinine tests as screening methods of chronic kidney disease in Vietnamese patients.

    Science.gov (United States)

    Pham, Thuy Anh Vu

    2017-11-01

    The aims of this case control study were to correlate the serum and salivary urea as well as creatinine levels; and to evaluate salivary urea and creatinine as noninvasive alternatives to serum for creatinine estimation in chronic kidney disease (CKD) patients. Blood and saliva samples were collected from 112 CKD patients and 108 subjects without CKD for quantitative analysis of urea and creatinine. Spearman's correlation coefficients between salivary and serum urea as well as creatinine were obtained. Receiver operating characteristic analysis was done to assess the diagnostic tests of salivary urea and creatinine. Cut-off values were determined based on the best trade-off between the sensitivity and specificity for both salivary urea and creatinine. Salivary urea and creatinine concentrations were significantly higher in CKD patients than those in control subjects; and increased by the stages of the severity of the disease. The positive correlation was significantly found between salivary and serum creatinine (r  =  0.90) and between salivary and serum urea (r  =  0.73). Area under the curve for salivary urea was 0.76 and a cut-off value of 14.25 mmol/L gave a sensitivity of 82.9% and specificity of 57.8%. Area under the curve for salivary creatinine was 0.92 and a cut-off value of 0.24 mg/dL gave a sensitivity of 86.5% and specificity of 87.2%. Both salivary urea and creatinine have a high capacity for serum creatinine estimation. Salivary urea and creatinine tests can be used as low-cost, easily accessible and noninvasive tools for screening, diagnosing, monitoring treatment outcomes and ascertaining prognosis of chronic kidney disease.

  19. Methodological aspects of breath hydrogen (H2) analysis. Evaluation of a H2 monitor and interpretation of the breath H2 test

    DEFF Research Database (Denmark)

    Rumessen, J J; Kokholm, G; Gudmand-Høyer, E

    1987-01-01

    The reliability of end-expiratory hydrogen (H2) breath tests were assessed and the significance of some important pitfalls were studied, using a compact, rapid H2-monitor with electrochemical cells. The H2 response was shown to be linear and stable. The reproducibility of the breath collection...... were studied in 10 healthy adults during a 4-month period and they showed very marked inter- and intra-individual variability (16% above 40 p.p.m.). Initial peaks (early, short-lived H2 rises unrelated to carbohydrate malabsorption) were identified in 25% of the breath tests (in 4% above 20 p.......p.m). It is concluded that the technique used for interval sampling of end-expiratory breath samples for H2 concentration gives reliable results. The biological significance of H2 concentration increments can only be evaluated if the limitations of the technical procedures and the individual ability to produce H2...

  20. Investigation of some urea derivatives under in vitro conditions

    Energy Technology Data Exchange (ETDEWEB)

    Goersch, R; Bergner, H [Humboldt-Universitaet, Berlin (German Democratic Republic). Sektion Tierproduktion und Veterinaermedizin

    1978-10-01

    The protein synthesis from urea, isobutylidene diurea (IBDU), acetyl urea and urea phosphate was investigated in vitro under standardized conditions. The /sup 35/S incorporation into the trichloroacetic acid precipitable fraction of the fermentation mixture and the NH/sub 3/ level served as test criteria. If rumen juice of donor animals adapted to urea was used (test 1), only IBDU made possible a protein synthesis comparable to the urea preparation. Under conditions of IBDU adaption of the donor animals (test 2), urea, IBDU and urea phosphate proved to be of equal value. Acetyl urea showed considerably lower incorporation ratios, irrespective of the adaption of the donor animals.

  1. Investigation of some urea derivatives under in vitro conditions

    International Nuclear Information System (INIS)

    Goersch, R.; Bergner, H.

    1978-01-01

    The protein synthesis from urea, isobutylidene diurea (IBDU), acetyl urea and urea phosphate was investigated in vitro under standardized conditions. The 35 S incorporation into the trichloroacetic acid precipitable fraction of the fermentation mixture and the NH 3 level served as test criteria. If rumen juice of donor animals adapted to urea was used (test 1), only IBDU made possible a protein synthesis comparable to the urea preparation. Under conditions of IBDU adaption of the donor animals (test 2), urea, IBDU and urea phosphate proved to be of equal value. Acetyl urea showed considerably lower incorporation ratios, irrespective of the adaption of the donor animals. (author)

  2. Pseudomonas aeruginosa cytochrome c551 denaturation by five systematic urea derivatives that differ in the alkyl chain length.

    Science.gov (United States)

    Kobayashi, Shinya; Fujii, Sotaro; Koga, Aya; Wakai, Satoshi; Matubayasi, Nobuyuki; Sambongi, Yoshihiro

    2017-07-01

    Reversible denaturation of Pseudomonas aeruginosa cytochrome c 551 (PAc 551 ) could be followed using five systematic urea derivatives that differ in the alkyl chain length, i.e. urea, N-methylurea (MU), N-ethylurea (EU), N-propylurea (PU), and N-butylurea (BU). The BU concentration was the lowest required for the PAc 551 denaturation, those of PU, EU, MU, and urea being gradually higher. Furthermore, the accessible surface area difference upon PAc 551 denaturation caused by BU was found to be the highest, those by PU, EU, MU, and urea being gradually lower. These findings indicate that urea derivatives with longer alkyl chains are stronger denaturants. In this study, as many as five systematic urea derivatives could be applied for the reversible denaturation of a single protein, PAc 551 , for the first time, and the effects of the alkyl chain length on protein denaturation were systematically verified by means of thermodynamic parameters.

  3. Isotopic studies of urea metabolism in rabbits

    Science.gov (United States)

    Regoeczi, E.; Irons, L.; Koj, A.; McFarlane, A. S.

    1965-01-01

    1. The half-life of [15N]urea was found to be significantly longer than that of [14C]urea injected at the same time, the differences being due to endogenous catabolism of urea, which is accompanied by little or no reutilization of 14C but is approx. 20% for 15N. [15N]Urea therefore appears to be valueless as an indicator of nitrogen metabolism unless the extents of endogenous catabolism of urea and of fractional reutilization of 15N can be separately estimated. 2. Though measurements of the radioactivity of expired 14CO2 confirmed the existence of considerable urea catabolism these could not be used for quantitative assessments. 3. Alternative graphical methods based on [14C]urea specific activities in plasma and urine samples were used to calculate the fraction of urea production that is excreted. Values by the two methods were in good agreement and showed that some animals excrete less than half the urea that they produce. 4. Specific activity differences between simultaneous samples of urinary and plasma urea reflect the presence of a pool of urea in the kidney that is not in equilibrium with the body urea pool. Calculations indicate the presence of urea in the kidney that in some cases may represent as much as 15% of the body pool, and in two animals in which post-mortem renal analyses were performed the masses of urea found agreed closely with the calculated values. 5. A model for urea metabolism is proposed that includes this pool in the excretory pathway. The related theory is shown to be adequate to explain the shape of the specific activity curves of urinary urea from the time of injection and the constant delay of the specific activity of urinary urea, relative to that of plasma urea, that is observed after a short preliminary equilibration period. 6. The body urea pool was calculated from the activity retained at 1·5hr. by excluding renal activity and the corrected specific activity of plasma urea at the same time. The urea pool was calculated to be

  4. KOMBINASI PENAMBAHAN UREA DAN EM-4 TERHADAP KUALITAS BOKASHI CAIR

    Directory of Open Access Journals (Sweden)

    Muhammad Dzulfikri Haidla

    2016-06-01

    Full Text Available The objectives of the study is to determine the effect of EM-4 and Urea addition on the liquid Bokashi quality of chicken manure. The field research was conducted at California Papaya Farm Pulau Sari, Pelaihari, and the nutrient levels of liquid Bokashi are then analyzed in the laboratory of PPLH Banjarbaru. The research was conducted from February to March 2015. It used Complete Randomized Design (CRD of factorial pattern 2 with three levels of treatment and three replications, the first factor is the addition of urea, consisting of three levels those are 0 g, 7.5 g, 15 g, the second factor is the addition of EM-4, consisting of three levels those are 0 ml, 25 ml, 50 ml, so that the number of trial units becomes 27 units. The variables measured are the Levels of Nitrogen (N, Phosphorous (P, Potassium (K, C-Organic, temperature, pH, color, smell, and texture. Quantitative observation data were analyzed using ANOVA and Duncan's Multiple Range Test (DMRT, while the qualitative observation data were analyzed using Kruskal-Wallis test. The results showed that the interaction between the addition of EM-4 and Urea were able to increase levels of nutrients N, P, K, C-Organic, and the temperature of the liquid Bokashi. Overall obtained treatment provision of EM-4 25 ml and 15 g Urea is the best treatment among other treatments. The addition of EM-4 was able to increase the levels of N, K, C-Organic and liquid Bokashi temperature, but it is unable to increase levels of the element P. Giving Urea can increase the levels of nutrients N, P, K, C-Organic, and the temperature of the liquid Bokashi. In observation of the organoleptic treatment with the addition of EM-4 and Urea, it tends to produce materials with better color, smell, and texture than the control treatment.

  5. Limitations in the use of 14C-glycocholate breath and stool bile acid determinations in patients with chronic diarrhea

    International Nuclear Information System (INIS)

    Ferguson, J.; Walker, K.; Thomson, A.B.

    1986-01-01

    Analysis of a modified 14 C-glycocholate breath test on 165 consecutive in-patients being investigated for chronic diarrhea showed that the measurement of 14 CO 2 between 3 and 6 h after oral dosing of 5 microCi of 14 C-glycocholic acid was of only limited use to distinguish between patients with Crohn's disease (CD), idiopathic bile salt wastage (IBW), or ileal resection (IR) from those with the irritable bowel syndrome (IBS). Continuing 14 CO 2 collections for up to 24 h was of little more help in establishing the presence of bacterial overgrowth syndrome (BOS) and in distinguishing between BOS and CD. Stool bile acid measurements were of use in differentiating between IBW and IBS, but did not distinguish between CD and BOS or between CD and IR. Since the range of normal values was defined by measurements in the IBS group, a positive test was specific for an organic cause of chronic diarrhea. Even so, the sensitivity of the test was relatively low: CD, 53%; IR, 23%; IBW, 14 %; and BOS, 10%. We believe that the 24-h 14 C-glycocholic breath test combined with the measurement of stool bile acids represents a screening test of only limited use for the identification of organic causes of chronic diarrhea

  6. Utilization of labelled urea in Helicobacter pylori eradication study by Espinheira Santa

    International Nuclear Information System (INIS)

    Chausson, Yvon; Coelho, Luiz Gonzaga Vaz; Passos, Maria do Carmo Friche; Andrade, Angela Almeida Magalhaes; Paiva Leriza, Duilio de; Paula Castro, Luiz de

    1995-01-01

    Maytenus ilicifolia, Espinheira Santa, is usually used to treat some gastric diseases, in special duodenal ulcer, in agreement with the medical literature. The aim of this work was to verify the efficiency of those leaves in such disease. It was selected a group of volunteers with ulcer caused by Helicobacter pylori (Hp) confirmed by Urea Breath Test (UBT). It was administered to all patients one capsule having 300 mg of dry extract of the leaves 20 minutes before the UBT. The capsule went on being administered during a week three times a day. At the end of this period two tests were applied to evaluate the Hp eradication: one 12 hours just after the treatment and another after one month. The results indicated that the antibiotic action was not confirmed. (author). 4 refs., 1 fig

  7. Quantitative aspect of the endogenous urea cycle in goats

    International Nuclear Information System (INIS)

    Ide, Yu

    1975-01-01

    The turnover of plasma urea was studied in goats fed rations with different protein contents by using 14 C- and 15 N-urea as tracers. The biological half-life time of urea determined with 15 N-urea was always longer than that determined with 14 C-urea, reflecting the difference in the metabolic pathway between the urea hydrolysates, ammonia and carbon dioxide. It was roughly estimated from the turnover studies that more than a half the quantity of urea synthesized might be transferred to the alimentary canal, including the rumen, where it underwent dissociation, with a decrease in the protein content of the ration, the percentage of transfer and dissociation increased. The 14 C-urea discharged into the urine was less than 57% of the administered dose. It decreased to 3.9% in goats fed rations with a low protein content. The rate of urea turnover determined with 15 N-urea was nearly consistent with the rate of urea discharge into the urine in goats fed higher protein rations. In goats fed lower protein rations, on the other hand, the rate of urea discharge decreased and its consistency with the rate of turnover determined with 15 N-urea was upset. This was caused by assimilation of urea-nitrogen in rumen microorganisms, as was convinced by studying the incorporation of urea- 15 N into the fraction of rumen microorganisms. It was assumed that in goats fed lower protein rations the bulk of urea synthesized might have entered the endogenous recycling system within the body and assimilated by rumen microorganisms. (auth.)

  8. Hepatic urea biosynthesis in the euryhaline elasmobranch Carcharhinus leucas.

    Science.gov (United States)

    Anderson, W Gary; Good, Jonathan P; Pillans, Richard D; Hazon, Neil; Franklin, Craig E

    2005-10-01

    Plasma urea levels and hepatic urea production in the euryhaline bull shark, Carcharhinus leucas, acclimated to freshwater and seawater environments were measured. It was found that plasma urea concentration increased with salinity and that this increase was, in part, the result of a significant increase in hepatic production of urea. This study provides direct evidence that hepatic production of urea plays an important role in the osmoregulatory strategy of C. leucas. (c) 2005 Wiley-Liss, Inc.

  9. Effect of influenza vaccination on oxidative stress products in breath.

    Science.gov (United States)

    Phillips, Michael; Cataneo, Renee N; Chaturvedi, Anirudh; Danaher, Patrick J; Devadiga, Anantrai; Legendre, David A; Nail, Kim L; Schmitt, Peter; Wai, James

    2010-06-01

    Viral infections cause increased oxidative stress, so a breath test for oxidative stress biomarkers (alkanes and alkane derivatives) might provide a new tool for early diagnosis. We studied 33 normal healthy human subjects receiving scheduled treatment with live attenuated influenza vaccine (LAIV). Each subject was his or her own control, since they were studied on day 0 prior to vaccination, and then on days 2, 7 and 14 following vaccination. Breath volatile organic compounds (VOCs) were collected with a breath collection apparatus, then analyzed by automated thermal desorption with gas chromatography and mass spectroscopy. A Monte Carlo simulation technique identified non-random VOC biomarkers of infection based on their C-statistic values (area under curve of receiver operating characteristic). Treatment with LAIV was followed by non-random changes in the abundance of breath VOCs. 2, 8-Dimethyl-undecane and other alkane derivatives were observed on all days. Conservative multivariate models identified vaccinated subjects on day 2 (C-statistic = 0.82, sensitivity = 63.6% and specificity = 88.5%); day 7 (C-statistic = 0.94, sensitivity = 88.5% and specificity = 92.3%); and day 14 (C-statistic = 0.95, sensitivity = 92.3% and specificity = 92.3%). The altered breath VOCs were not detected in live attenuated influenza vaccine, excluding artifactual contamination. LAIV vaccination in healthy humans elicited a prompt and sustained increase in breath biomarkers of oxidative stress. A breath test for these VOCs could potentially identify humans who are acutely infected with influenza, but who have not yet developed clinical symptoms or signs of disease.

  10. A better state-of-mind: deep breathing reduces state anxiety and enhances test performance through regulating test cognitions in children.

    Science.gov (United States)

    Khng, Kiat Hui

    2017-11-01

    A pre-test/post-test, intervention-versus-control experimental design was used to examine the effects, mechanisms and moderators of deep breathing on state anxiety and test performance in 122 Primary 5 students. Taking deep breaths before a timed math test significantly reduced self-reported feelings of anxiety and improved test performance. There was a statistical trend towards greater effectiveness in reducing state anxiety for boys compared to girls, and in enhancing test performance for students with higher autonomic reactivity in test-like situations. The latter moderation was significant when comparing high-versus-low autonomic reactivity groups. Mediation analyses suggest that deep breathing reduces state anxiety in test-like situations, creating a better state-of-mind by enhancing the regulation of adaptive-maladaptive thoughts during the test, allowing for better performance. The quick and simple technique can be easily learnt and effectively applied by most children to immediately alleviate some of the adverse effects of test anxiety on psychological well-being and academic performance.

  11. Organic Gas Sensor with an Improved Lifetime for Detecting Breath Ammonia in Hemodialysis Patients.

    Science.gov (United States)

    Chuang, Ming-Yen; Chen, Chang-Chiang; Zan, Hsiao-Wen; Meng, Hsin-Fei; Lu, Chia-Jung

    2017-12-22

    In this work, a TFB (poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-s-butylphenyl)diphenylamine)]) sensor with a cylindrical nanopore structure exhibits a high sensitivity to ammonia in ppb-regime. The lifetime and sensitivity of the TFB sensor were studied and compared to those of P3HT (poly(3-hexylthiophene)), NPB (N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine), and TAPC (4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl) benzenamine]) sensors with the same cylindrical nanopore structures. The TFB sensor outstands the others in sensitivity and lifetime and it shows a sensing response (current variation ratio) of 13% to 100 ppb ammonia after 64 days of storage in air. A repeated sensing periods testing and a long-term measurement have also been demonstrated for the test of robustness. The performance of the TFB sensor is stable in both tests, which reveals that the TFB sensor can be utilized in our targeting clinical trials. In the last part of this work, we study the change of ammonia concentration in the breath of hemodialysis (HD) patients before and after dialysis. An obvious drop of breath ammonia concentration can be observed after dialysis. The reduction of breath ammonia is also correlated with the reduction of blood urea nitrogen (BUN). A correlation coefficient of 0.82 is achieved. The result implies that TFB sensor may be used as a real-time and low cost breath ammonia sensor for the daily tracking of hemodialysis patients.

  12. Redox Thermodynamics of Cytochromes c Subjected to Urea Induced Unfolding

    OpenAIRE

    Monari, S.; Ranieri, A.; Di Rocco, G.; van der Zwan, G.; Peressini, S.; Tavagnacco, C.; Millo, D.; Borsari, M.

    2009-01-01

    The thermodynamics of the electron transfer (ET) process for beef heart and yeast cytochromes c and the Lys72Ala/Lys73Ala/Lys79Ala mutant of the latter species subjected to progressive urea-induced unfolding was determined electrochemically. The results indicate the presence of at least three protein forms which were assigned to a low-temperature and a high-temperature His-Met intermediate species and a bis-histidinate form (although the presence of a His-Lys form cannot be excluded). The muc...

  13. Radiation exposure of the patient in diagnostic nuclear medicine. Experimental studies of the biokinetics of 111In-DTPA-D-Phe1-octreotide, 99mTc-MIBI, 14C-triolein and 14C-urea, and development of dosimetric models

    International Nuclear Information System (INIS)

    Leide Svegborn, S.

    1999-03-01

    Biokinetic and dosimetric models for a number of clinically used radiopharmaceuticals, for which information on the radiation dosimetry is scarce, have been produced. On patients undergoing investigations with 111 In-DTPA-D-Phe 1 -octreotide (for diagnosis of neuroendocrine tumours) and 99m Tc-MIBI (for myocardial perfusion imaging), whole body gamma camera scanning was performed several times after administration of the radiopharmaceutical. Total body and organ activity content was determined using the geometric mean of the number of counts in two 180 deg opposed planar images. A thorough investigation of sources influencing the accuracy of the quantification of activity was carried out, showing an overall uncertainty varying from 10% to 30% for organs with a significant uptake and 5% for the whole body. The activity in blood and urine was also measured. 111 In-DTPA-D-Phe 1 -octreotide was predominantly excreted via the kidney-bladder system and a typical investigation with 1200 MBq resulted in an effective dose of 8.4 mSv (0.076 mSv/MBq). 99m Tc-MIBI was to a great extent excreted via the gastrointestinal tract and an investigation with 1200 MBq resulted in an effective dose of 13 mSv (0.011 mSv/MBq). Accelerator mass spectrometry (AMS) was used to investigate the possibility to measure ultra-low activity concentrations of 14 CO 2 , in exhaled air from patients undergoing 14 C-breath tests, with special application to 14 C-triolein (for study of fat malabsorption). AMS was proven to be a useful technique for long-term retention studies of 14 C, and was used together with liquid scintillation counting in an investigation of the biokinetics of 14 C-urea in adult and paediatric patients (for diagnosis of Helicobacter pylori infection in the upper gastrointestinal tract). The effective dose for 14 C-urea was 0.019 mSv/MBq for adults and from 0.041 to 0.019 mSv/MBq for seven- to fourteen -year-old children, resulting in an effective dose of approximately 0.002 mSv per

  14. Total synthesis of [2-11C]thymidine from [11C]urea: A tracer of choice for measurement of cellular proliferation using PET

    International Nuclear Information System (INIS)

    Labar, D.; Vander Borght, T.

    1990-01-01

    In preliminary studies of cellular proliferation with [methyl- 11 C]thymidine, the labelled degradative products mask the progressive incorporation of the tracer into DNA. The authors have developed a procedure for the synthesis of [2- 11 C]thymidine to circumvent this difficulty, using a [ 11 C]urea precursor

  15. Transfer of blood urea into the goat colon

    International Nuclear Information System (INIS)

    Engelhardt, W. von; Hinderer, S.

    1976-01-01

    Transfer of blood urea to the temporarily isolated and perfused colon of conscious goats was measured. Simultaneously, total urea turnover was estimated using 14 C-labelled urea. Three animals in the weight range 50-70 k were used, with appropriately placed cannulae. The entry of blood urea into the total gastrointestinal tract was estimated from the difference between total urea turnover renal urea excretion. When experimental conditions remained constant, such as the permeability of the gastrointestinal tract wall, blood urea diffusion into the colon depended on plasma urea concentration. Results of varying feeding conditions demonstrated that changes in permeability of the gastrointestinal tract will have a more pronounced influence on the amounts of blood urea entering the gastrointestinal tract than differences in plasma urea concentration

  16. Activity calibration in breath test for diagnosis of Helicobacter pylori

    International Nuclear Information System (INIS)

    Wasilewka-Radwanska, M.; Pysklak, S.; Gilewicz-Wolter, J.; Kuc, T.; Jung, A.; Niziol, J.; Kopanski, J.; Micherdzinski, J.; Cienciala, A.

    1996-01-01

    Some technical and measurement problems of the breath test for diagnosis of Helicobacter pylori are briefly discussed. Calibrated results obtained for population of 108 cases indicate difference between HP+ (infected with Helicobacter pylori) and HP- (non infected with Helicobacter pylori) in exhaled 14 C activity not less than 3.9 kBq while the lower limit for HP+ cases was set at 6.8 kBq at the detection limit: 0.9 Bq/mmol of CO 2 . It was estimated that in exhalation way up to 29% of the taken activity was removed in HP+ cases during first 35 minutes. Radiation hazard for the patient system is negligibly small - dose equipment not exceeds 0.29% of the natural (environmental) yearly exposure. (author)

  17. Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults

    Science.gov (United States)

    Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

    2016-01-01

    Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia. We measured breath ammonia in real time by quartz enhanced photoacoustic spectrometry and blood ammonia in 10 healthy and 10 cirrhotic participants. Each participant contributed 5 breath samples and blood for ammonia measurement within 1 h. We calculated the coefficient of variation (CV) for 5 breath ammonia values, reported medians of healthy and cirrhotic participants, and used scatterplots to display breath and blood ammonia. For healthy participants, mean age was 22 years (±4), 70% were men, and body mass index (BMI) was 27 (±5). For cirrhotic participants, mean age was 61 years (±8), 60% were men, and BMI was 31 (±7). Median blood ammonia for healthy participants was within normal range, 10 μmol L−1 (interquartile range (IQR), 3–18) versus 46 μmol L−1 (IQR, 23–66) for cirrhotic participants. Median breath ammonia was 379 pmol mL−1 CO2 (IQR, 265–765) for healthy versus 350 pmol mL−1 CO2 (IQR, 180–1013) for cirrhotic participants. CV was 17 ± 6%. There remains an important unmet need in the evaluation of systemic ammonia, and breath measurement continues to demonstrate promise to fulfill this need. Given the many differences between breath and blood ammonia measurement, we examined biological explanations for our findings in healthy and cirrhotic participants. We conclude that based upon these preliminary data breath may offer clinically important information this is not provided by blood ammonia. PMID:26658550

  18. An acetone breath analyzer using cavity ringdown spectroscopy: an initial test with human subjects under various situations

    International Nuclear Information System (INIS)

    Wang, Chuji; Surampudi, Anand B

    2008-01-01

    We have developed a portable breath acetone analyzer using cavity ringdown spectroscopy (CRDS). The instrument was initially tested by measuring the absorbance of breath gases at a single wavelength (266 nm) from 32 human subjects under various conditions. A background subtraction method, implemented to obtain absorbance differences, from which an upper limit of breath acetone concentration was obtained, is described. The upper limits of breath acetone concentration in the four Type 1 diabetes (T1D) subjects, tested after a 14 h overnight fast, range from 0.80 to 3.97 parts per million by volume (ppmv), higher than the mean acetone concentration (0.49 ppmv) in non-diabetic healthy breath reported in the literature. The preliminary results show that the instrument can tell distinctive differences between the breath from individuals who are healthy and those with T1D. On-line monitoring of breath gases in healthy people post-exercise, post-meals and post-alcohol-consumption was also conducted. This exploratory study demonstrates the first CRDS-based acetone breath analyzer and its potential application for point-of-care, non-invasive, diabetic monitoring

  19. A mechanical breathing simulator for respirator test

    International Nuclear Information System (INIS)

    Murata, Mikio; Ikezawa, Yoshio; Yoshida, Yoshikazu

    1976-01-01

    A mechanical breathing simulator has been developed to produce the human respiration for use in respirator test. The respirations were produced through the strokes of piston controlled by a rockerarm with adjustable fulcrum. The respiration rate was governed by motor-speed control, independent of the tidal volume achieved by adjustment of the piston stroke. By the breather, the simulated respirations for work rate 0, 208, 415, 622 and 830 kg-m/min could be produced through the typical dummy head. (auth.)

  20. The Effect of Alcohol-Based Hand Sanitizer Vapors on Evidential Breath Alcohol Test Results.

    Science.gov (United States)

    Strawsine, Ellen; Lutmer, Brian

    2017-11-16

    This study was undertaken to determine if the application of alcohol-based hand sanitizers (ABHSs) to the hands of a breath test operator will affect the results obtained on evidential breath alcohol instruments (EBTs). This study obtained breath samples on three different EBTs immediately after application of either gel or foam ABHS to the operator's hands. A small, but significant, number of initial analyses (13 of 130, 10%) resulted in positive breath alcohol concentrations, while 41 samples (31.5%) resulted in a status code. These status codes were caused by ethanol vapors either in the room air or their inhalation by the subject, thereby causing a mouth alcohol effect. Replicate subject samples did not yield any consecutive positive numeric results. As ABHS application can cause a transitory mouth alcohol effect via inhalation of ABHS vapors, EBT operators should forego the use of ABHS in the 15 min preceding subject testing. © 2017 American Academy of Forensic Sciences.

  1. A Modified Carbon Monoxide Breath Test for Measuring Erythrocyte Lifespan in Small Animals

    Directory of Open Access Journals (Sweden)

    Yong-Jian Ma

    2016-01-01

    Full Text Available This study was to develop a CO breath test for RBC lifespan estimation of small animals. The ribavirin induced hemolysis rabbit models were placed individually in a closed rebreath cage and air samples were collected for measurement of CO concentration. RBC lifespan was calculated from accumulated CO, blood volume, and hemoglobin concentration data. RBC lifespan was determined in the same animals with the standard biotin-labeling method. RBC lifespan data obtained by the CO breath test method for control (CON, 49.0±5.9 d rabbits, rabbits given 10 mg/kg·d−1 of ribavirin (RIB10, 31.0±4.0 d, and rabbits given 20 mg/kg·d−1 of ribavirin (RIB20, 25.0±2.9 d were statistically similar (all p>0.05 to and linearly correlated (r=0.96, p<0.01 with the RBC lifespan data obtained for the same rabbits by the standard biotin-labeling method (CON, 51.0±2.7 d; RIB10, 33.0±1.3 d; and RIB20, 27.0±0.8 d. The CO breath test method takes less than 3 h to complete, whereas the standard method requires at least several weeks. In conclusion, the CO breath test method provides a simple and rapid means of estimating RBC lifespan and is feasible for use with small animal models.

  2. The Effect of Annealing Temperature on Nickel on Reduced Graphene Oxide Catalysts on Urea Electrooxidation

    International Nuclear Information System (INIS)

    Glass, Dean E.; Galvan, Vicente; Prakash, G.K. Surya

    2017-01-01

    Highlights: •Nickel was reduced on graphene oxide and annealed under argon from 300 to 700 °C. •Nickel was oxidized from the removal of oxygen groups on the graphene oxide. •Higher annealed catalysts displayed decreased urea electrooxidation currents. •Micro direct urea/hydrogen peroxide fuel cells were employed for the first time. •Ni/rGO catalysts displayed enhanced fuel cell performance than the bare nickel. -- Abstract: The annealing temperature effects on nickel on reduced graphene oxide (Ni/rGO) catalysts for urea electrooxidation were investigated. Nickel chloride was directly reduced in an aqueous solution of graphene oxide (GO) followed by annealing under argon at 300, 400, 500, 600, and 700 °C, respectively. X-ray Diffraction (XRD) patterns revealed an increase in the crystallite size of the nickel nanoparticles while the Raman spectra displayed an increase in the graphitic disorder of the reduced graphene oxide at higher annealing temperatures due to the removal of oxygen functional groups. The Ni/rGO catalysts annealed at higher temperatures displayed oxidized nickel surface characteristics from the Ni 2p X-ray Photoelectron Spectra (XPS) due to the oxidation of the nickel from the oxygen functional groups in the graphitic lattice. In the half-cell testing, the onset potential of urea electrooxidation decreased while the urea electrooxidation currents decreased as the annealing temperature was increased. The nickel catalyst annealed at 700 °C displayed a 31% decrease in peak power density while the catalyst annealed at 300 °C displayed a 13% increase compared with the unannealed Ni/rGO catalyst in the micro direct urea/hydrogen peroxide fuel cells tests.

  3. Urea-formaldehyde resins: production, application, and testing

    Science.gov (United States)

    Nuryawan, A.; Risnasari, I.; Sucipto, T.; Heri Iswanto, A.; Rosmala Dewi, R.

    2017-07-01

    Urea-formaldehyde (UF) resin, one of the most important formaldehyde resin adhesives, is a polymeric condensation product of formaldehyde with urea, and being widely used for the manufacture of wood-based composite panels, such as plywood, particleboard, and fiberboard. In spite of its benefits such as fast curing, good performance in the panels (colorless), and lower cost; formaldehyde emission (FE) originated from either UF resin itself or composite products bonded by UF resins is considered a critical drawback as it affects human health particularly in indoor environment. In order to reduce the FE, lowering formaldehyde/urea (F/U) mole ratio in the synthesis of the UF resin was done. In this study, synthesis of UF resins was carried out following the conventional alkaline-acid two-step reaction with a second addition of urea, resulting in F/U mole ratio around 1.0, namely 0.95; 1.05, and 1.15. The UF resins produced were used as binder for particleboard making. The board was manufactured in the laboratory using shaving type particle of Gmelina wood, 8% UF resin based on oven dry particle, and 1% NH4Cl (20%wt) as hardener for the resin. The target of the thickness was 10 mm and the dimension was 25 cm x 25 cm. The resulted particleboard then was evaluated the physical and the mechanical properties by Japanese Industrial Standard (JIS) A 5908 (2003). Further, the resulted particleboard also was used for the mice cage’s wall in order to mimic the real living environment. After four weeks exposure in the cages, the mice then were evaluated their mucous organs as well as their blood. The experiment results were as follows: 1) It was possible to synthesis UF resins with low F/U mole ratio; 2) However, the particleboard bonded UF resins with low F/U mole ratio showed poor properties, particularly on the thickness swelling and modulus of elasticity; 3) There was no significant differences among the mucous organs of the mice after a month exposure FE originated from

  4. Fast-starting after a breath: air-breathing motions are kinematically similar to escape responses in the catfish Hoplosternum littorale

    Directory of Open Access Journals (Sweden)

    Paolo Domenici

    2014-12-01

    Full Text Available Fast-starts are brief accelerations commonly observed in fish within the context of predator–prey interactions. In typical C-start escape responses, fish react to a threatening stimulus by bending their body into a C-shape during the first muscle contraction (i.e. stage 1 which provides a sudden acceleration away from the stimulus. Recently, similar C-starts have been recorded in fish aiming at a prey. Little is known about C-starts outside the context of predator–prey interactions, though recent work has shown that escape response can also be induced by high temperature. Here, we test the hypothesis that air-breathing fish may use C-starts in the context of gulping air at the surface. Hoplosternum littorale is an air-breathing freshwater catfish found in South America. Field video observations reveal that their air-breathing behaviour consists of air-gulping at the surface, followed by a fast turn which re-directs the fish towards the bottom. Using high-speed video in the laboratory, we compared the kinematics of the turn immediately following air-gulping performed by H. littorale in normoxia with those of mechanically-triggered C-start escape responses and with routine (i.e. spontaneous turns. Our results show that air-breathing events overlap considerably with escape responses with a large stage 1 angle in terms of turning rates, distance covered and the relationship between these rates. Therefore, these two behaviours can be considered kinematically comparable, suggesting that air-breathing in this species is followed by escape-like C-start motions, presumably to minimise time at the surface and exposure to avian predators. These findings show that C-starts can occur in a variety of contexts in which fish may need to get away from areas of potential danger.

  5. Compressed air demand-type firefighter's breathing system, volume 1. [design analysis and performance tests

    Science.gov (United States)

    Sullivan, J. L.

    1975-01-01

    The commercial availability of lightweight high pressure compressed air vessels has resulted in a lightweight firefighter's breathing apparatus. The improved apparatus, and details of its design and development are described. The apparatus includes a compact harness assembly, a backplate mounted pressure reducer assembly, a lightweight bubble-type facemask with a mask mounted demand breathing regulator. Incorporated in the breathing regulator is exhalation valve, a purge valve and a whistle-type low pressure warning that sounds only during inhalation. The pressure reducer assembly includes two pressure reducers, an automatic transfer valve and a signaling device for the low pressure warning. Twenty systems were fabricated, tested, refined through an alternating development and test sequence, and extensively examined in a field evaluation program. Photographs of the apparatus are included.

  6. Chemical sensors for breath gas analysis: the latest developments at the Breath Analysis Summit 2013.

    Science.gov (United States)

    Tisch, Ulrike; Haick, Hossam

    2014-06-01

    Profiling the body chemistry by means of volatile organic compounds (VOCs) in the breath opens exciting new avenues in medical diagnostics. Gas sensors could provide ideal platforms for realizing portable, hand-held breath testing devices in the near future. This review summarizes the latest developments and applications in the field of chemical sensors for diagnostic breath testing that were presented at the Breath Analysis Summit 2013 in Wallerfangen, Germany. Considerable progress has been made towards clinically applicable breath testing devices, especially by utilizing chemo-sensitive nanomaterials. Examples of several specialized breath testing applications are presented that are either based on stand-alone nanomaterial-based sensors being highly sensitive and specific to individual breath compounds over others, or on combinations of several highly specific sensors, or on experimental nanomaterial-based sensors arrays. Other interesting approaches include the adaption of a commercially available MOx-based sensor array to indirect breath testing applications, using a sample pre-concentration method, and the development of compact integrated GC-sensor systems. The recent trend towards device integration has led to the development of fully integrated prototypes of point-of-care devices. We describe and compare the performance of several prototypes that are based on different sensing technologies and evaluate their potential as low-cost and readily available next-generation medical devices.

  7. Methacholine challenge test: Comparison of tidal breathing and dosimeter methods in children.

    Science.gov (United States)

    Mazi, Ahlam; Lands, Larry C; Zielinski, David

    2018-02-01

    Methacholine Challenge Test (MCT) is used to confirm, assess the severity and/or rule out asthma. Two MCT methods are described as equivalent by the American Thoracic Society (ATS), the tidal breathing and the dosimeter methods. However, the majority of adult studies suggest that individuals with asthma do not react at the same PC 20 between the two methods. Additionally, the nebulizers used are no longer available and studies suggest current nebulizers are not equivalent to these. Our study investigates the difference in positive MCT tests between three methods in a pediatric population. A retrospective, chart review of all MCT performed with spirometry at the Montreal Children's Hospital from January 2006 to March 2016. A comparison of the percentage positive MCT tests with three methods, tidal breathing, APS dosimeter and dose adjusted DA-dosimeter, was performed at different cutoff points up to 8 mg/mL. A total of 747 subjects performed the tidal breathing method, 920 subjects the APS dosimeter method, and 200 subjects the DA-dosimeter method. At a PC 20 cutoff ≤4 mg/mL, the percentage positive MCT was significantly higher using the tidal breathing method (76.3%) compared to the APS dosimeter (45.1%) and DA-dosimeter (65%) methods (P < 0.0001). The choice of nebulizer and technique significantly impacts the rate of positivity when using MCT to diagnose and assess asthma. Lack of direct comparison of techniques within the same individuals and clinical assessment should be addressed in future studies to standardize MCT methodology in children. © 2017 Wiley Periodicals, Inc.

  8. Cross sections for 12C+12C→12C(0+2)+12C(g.s.) using breathing mode doorways

    International Nuclear Information System (INIS)

    Ahmed, M.U.; Beres, W.P.

    1982-01-01

    A previously derived projection operator method is applied to the calculation of the cross section for 12 C+ 12 C→ 12 C(0 + 2 )+ 12 C(g.s.) with a breathing mode model being used to describe the 0 + 2 (7.68 MeV) state of 12 C. The relationship to processes leading to alpha particle channels is discussed. The cross section for 12 C+ 12 C→ 12 C(3 - )+ 12 C(g.s.) is also calculated and possible correlations with inelastic scattering to the 0 + 2 and 2 + states of 12 C are discussed. The results for both 0 + 2 and 3 - inelastic scattering are in reasonable agreement with experiment

  9. Evaluation of (CO2)-C-13 breath tests for the detection of fructose malabsorption

    NARCIS (Netherlands)

    Hoekstra, JH; VandenAker, JHL; Kneepkens, CMF; Stellaard, F; Geypens, B; Ghoos, YF

    Breath hydrogen (H-2) studies have made clear that small intestinal absorption of fructose is limited, especially in toddlers. Malabsorption of fructose may be a cause of recurrent abdominal pain and chronic nonspecific diarrhea (toddler's diarrhea). Fructose absorption is facilitated by equimolar

  10. The impact of urea-induced unfolding on the redox process of immobilised cytochrome c

    NARCIS (Netherlands)

    Monari, S.; Millo, D.; Ranieri, A.; di Rocco, G.; van der Zwan, G.; Gooijer, C.; Peressini, S.; Tavagnacco, C.; Hildebrandt, P.; Borsari, M.

    2010-01-01

    We have studied the effect of urea-induced unfolding on the electron transfer process of yeast iso-1-cytochrome c and its mutant K72AK73AK79A adsorbed on electrodes coated by mixed 11-mercapto-1-undecanoic acid/11-mercapto-1-undecanol self-assembled monolayers. Electrochemical measurements,

  11. The elevated serum urea:creatinine ratio in canine babesiosis in South Africa is not of renal origin.

    Science.gov (United States)

    de Scally, M P; Leisewitz, A L; Lobetti, R G; Thompson, P N

    2006-12-01

    Pigmented serum, usually due to free haemoglobin and/or bilirubin, is a common finding in dogs with babesiosis, resulting in interference with all biochemical tests that rely on photochemistry. This is particularly true of urea and creatinine determinations, complicating the diagnosis of acute renal failure, which is a serious complication of babesiosis. A disproportionately raised serum urea concentration of unknown origin occurs in severely anaemic canine babesiosis patients and gives rise to an increased serum urea:creatinine ratio. The assay for cystatin-C, an excellent measure of glomerular filtration rate, is unaffected by free serum haemoglobin, and due to its different intrinsic origins, is free of influence by the metabolic derangements and organ pathology, other than renal disease, encountered in canine babesiosis. Serum cystatin-C was used to compare the concentrations of serum urea and serum creatinine in dogs with the severely anaemic form of canine babesiosis as well as a canine babesiosis-free reference group. Mean serum urea and mean serum urea:creatinine ratio were significantly elevated in the babesia-infected group relative to the reference population in this study. Mean serum creatinine and mean serum cystatin-C were within the reference ranges. Therefore an elevated urea:creatinine ratio in canine babesiosis in the presence of a normal serum creatinine concentration is considered to be caused by an elevated serum urea concentration and is most likely of non-renal origin. Serum creatinine was therefore as specific a measure of renal function as serum cystatin-C in canine babesiosis in this study. The sensitivity of serum creatinine as a measure of renal function was not established by this study. Serum urea, however, proved to be of little use compared to serum cystatin-C and serum creatinine. Serum urea should therefore not be used to diagnose renal failure in canine babesiosis.

  12. Aspiration tests in aqueous foam using a breathing simulator

    Energy Technology Data Exchange (ETDEWEB)

    Archuleta, M.M.

    1995-12-01

    Non-toxic aqueous foams are being developed by Sandia National Laboratories (SNL) for the National Institute of Justice (NIJ) for use in crowd control, cell extractions, and group disturbances in the criminal justice prison systems. The potential for aspiration of aqueous foam during its use and the resulting adverse effects associated with complete immersion in aqueous foam is of major concern to the NIJ when examining the effectiveness and safety of using this technology as a Less-Than-Lethal weapon. This preliminary study was designed to evaluate the maximum quantity of foam that might be aspirated by an individual following total immersion in an SNL-developed aqueous foam. A.T.W. Reed Breathing simulator equipped with a 622 Silverman cam was used to simulate the aspiration of an ammonium laureth sulfate aqueous foam developed by SNL and generated at expansion ratios in the range of 500:1 to 1000:1. Although the natural instinct of an individual immersed in foam is to cover their nose and mouth with a hand or cloth, thus breaking the bubbles and decreasing the potential for aspiration, this study was performed to examine a worst case scenario where mouth breathing only was examined, and no attempt was made to block foam entry into the breathing port. Two breathing rates were examined: one that simulated a sedentary individual with a mean breathing rate of 6.27 breaths/minute, and one that simulated an agitated or heavily breathing individual with a mean breathing rate of 23.7 breaths/minute. The results of this study indicate that, if breathing in aqueous foam without movement, an air pocket forms around the nose and mouth within one minute of immersion.

  13. Radiation exposure of the patient in diagnostic nuclear medicine. Experimental studies of the biokinetics of {sup 111}In-DTPA-D-Phe{sup 1}-octreotide, {sup 99m}Tc-MIBI, {sup 14}C-triolein and {sup 14}C-urea, and development of dosimetric models

    Energy Technology Data Exchange (ETDEWEB)

    Leide Svegborn, S

    1999-03-01

    Biokinetic and dosimetric models for a number of clinically used radiopharmaceuticals, for which information on the radiation dosimetry is scarce, have been produced. On patients undergoing investigations with {sup 111}In-DTPA-D-Phe{sup 1}-octreotide (for diagnosis of neuroendocrine tumours) and {sup 99m}Tc-MIBI (for myocardial perfusion imaging), whole body gamma camera scanning was performed several times after administration of the radiopharmaceutical. Total body and organ activity content was determined using the geometric mean of the number of counts in two 180 deg opposed planar images. A thorough investigation of sources influencing the accuracy of the quantification of activity was carried out, showing an overall uncertainty varying from 10% to 30% for organs with a significant uptake and 5% for the whole body. The activity in blood and urine was also measured. {sup 111}In-DTPA-D-Phe{sup 1}-octreotide was predominantly excreted via the kidney-bladder system and a typical investigation with 1200 MBq resulted in an effective dose of 8.4 mSv (0.076 mSv/MBq). {sup 99m}Tc-MIBI was to a great extent excreted via the gastrointestinal tract and an investigation with 1200 MBq resulted in an effective dose of 13 mSv (0.011 mSv/MBq). Accelerator mass spectrometry (AMS) was used to investigate the possibility to measure ultra-low activity concentrations of {sup 14}CO{sub 2}, in exhaled air from patients undergoing {sup 14}C-breath tests, with special application to {sup 14}C-triolein (for study of fat malabsorption). AMS was proven to be a useful technique for long-term retention studies of {sup 14}C, and was used together with liquid scintillation counting in an investigation of the biokinetics of {sup 14}C-urea in adult and paediatric patients (for diagnosis of Helicobacter pylori infection in the upper gastrointestinal tract). The effective dose for {sup 14}C-urea was 0.019 mSv/MBq for adults and from 0.041 to 0.019 mSv/MBq for seven- to fourteen -year-old children

  14. Degradation mechanism and thermal stability of urea nitrate below the melting point

    International Nuclear Information System (INIS)

    Desilets, Sylvain; Brousseau, Patrick; Chamberland, Daniel; Singh, Shanti; Feng, Hongtu; Turcotte, Richard; Anderson, John

    2011-01-01

    Highlights: → Decomposition mechanism of urea nitrate. → Spectral characterization of the decomposition mechanism. → Thermal stability of urea nitrate at 50, 70 and 100 o C. → Chemical balance of decomposed products released. - Abstract: Aging and degradation of urea nitrate below the melting point, at 100 o C, was studied by using thermal analysis and spectroscopic methods including IR, Raman, 1 H and 13 C NMR techniques. It was found that urea nitrate was completely degraded after 72 h at 100 o C into a mixture of solids (69%) and released gaseous species (31%). The degradation mechanism below the melting point was clearly identified. The remaining solid mixture was composed of ammonium nitrate, urea and biuret while unreacted residual nitric and isocyanic acids as well as traces of ammonia were released as gaseous species at 100 o C. The thermal stability of urea nitrate, under extreme storage conditions (50 o C), was also examined by isothermal nano-calorimetry.

  15. Early postoperative erythromycin breath test correlates with hepatic cytochrome P4503A activity in liver transplant recipients

    DEFF Research Database (Denmark)

    Schmidt, L E; Olsen, A K; Stentoft, K

    2001-01-01

    BACKGROUND: Interindividual variation in the pharmacokinetics of the immunosuppressive agents cyclosporine (INN, ciclosporin) and tacrolimus may result from differences in the activity of cytochrome P4503A (CYP3A). The erythromycin breath test is an in vivo assay of hepatic CYP3A activity......, but the method has never been directly validated. The aim of the study was to investigate whether an early postoperative erythromycin breath test correlated with the hepatic CYP3A protein level and catalytic activity in liver transplant recipients. METHODS: In 18 liver transplant recipients, the erythromycin...... breath test was performed within 2 hours after transplantation. A graft biopsy was obtained during surgery and analyzed for the CYP3A protein level by Western blotting and for CYP3A activity with erythromycin demethylation and testosterone 6beta- hydroxylation assays. RESULTS: The erythromycin breath...

  16. Comparison of the Quantitative Values of C-14 and C-13 UBT to Reflect the Presence and Degree of Ongoing Helicobacter pylori Infection

    International Nuclear Information System (INIS)

    Lim, Seok Tae; Kim, Dong Wook; Jeong, Hwan Jeong; Sohn, Myung Hee

    2008-01-01

    A urea breath test (UBT) using C-14 or C-13 has been developed for identifying Helicobacter (H) pylori infection on the basis of urease production with release of labeled CO 2 . We investigated if the C-14 and C-13 UBT have the difference to reflect the presence and degree of H. pylori infection detected by gastroduodenoscopic biopsies (GBx) in the same patients. Thirty eight patients (M:F=28:10, age 53.4±13.0 yrs) with upper gastrointestinal symptoms such as indigestion, gastric fullness or pain consecutively underwent C-14 UBT, GBx and C-13 UBT within one week before medications. For the C-14 UBT, a single breath sample was collected at 10 minutes after ingestion of C-14 urea (37 KBq) capsule and counting was done in a liquid scintillation counter for 1 minute, and the results were classified as positive (≥200 dpm), intermediate (50∼199 dpm) or negative (<50 dpm). For the C-13 UBT, the results were classified as positive (≥2.5) or negative (<2.5). The results of GBx with Giemsa stain were graded 0 (normal) to 4 (diffuse) according to the distribution of H. pylori by the Wyatt method. We compared C-14 UBT and C-13 UBT results with GBx grade as a gold standard. The prevalence of H. pylori infection by GBx with Giemsa stain was 25/38 (65.8%). In the assessment of the presence of H. pylori infection, the C-14 UBT global performance yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 92.0%, 92.3%, 95.8%, 91.7% and 92.1%, respectively. However, the C-13 UBT had sensitivity, specificity, PPV, NPV and accuracy of 96.0%, 84.6%, 92.3%, 91.7% and 92.1%, respectively. The more significant correlation in C-14 than C-13 UBT (r=0.948 vs r=0.819, p<0.001) was found between the value of UBT and the grade of distribution of H. pylori infection. We conclude that the diagnostic performance between C-14 and C-13 UBT to detect H. pylori infection is not significantly different, but the value of C-14 UBT more

  17. Comparison of the Quantitative Values of C-14 and C-13 UBT to Reflect the Presence and Degree of Ongoing Helicobacter pylori Infection

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Seok Tae; Kim, Dong Wook; Jeong, Hwan Jeong; Sohn, Myung Hee [Chonbuk National University Medical School, Jeonju (Korea, Republic of)

    2008-06-15

    A urea breath test (UBT) using C-14 or C-13 has been developed for identifying Helicobacter (H) pylori infection on the basis of urease production with release of labeled CO{sub 2}. We investigated if the C-14 and C-13 UBT have the difference to reflect the presence and degree of H. pylori infection detected by gastroduodenoscopic biopsies (GBx) in the same patients. Thirty eight patients (M:F=28:10, age 53.4{+-}13.0 yrs) with upper gastrointestinal symptoms such as indigestion, gastric fullness or pain consecutively underwent C-14 UBT, GBx and C-13 UBT within one week before medications. For the C-14 UBT, a single breath sample was collected at 10 minutes after ingestion of C-14 urea (37 KBq) capsule and counting was done in a liquid scintillation counter for 1 minute, and the results were classified as positive ({>=}200 dpm), intermediate (50{approx}199 dpm) or negative (<50 dpm). For the C-13 UBT, the results were classified as positive ({>=}2.5) or negative (<2.5). The results of GBx with Giemsa stain were graded 0 (normal) to 4 (diffuse) according to the distribution of H. pylori by the Wyatt method. We compared C-14 UBT and C-13 UBT results with GBx grade as a gold standard. The prevalence of H. pylori infection by GBx with Giemsa stain was 25/38 (65.8%). In the assessment of the presence of H. pylori infection, the C-14 UBT global performance yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 92.0%, 92.3%, 95.8%, 91.7% and 92.1%, respectively. However, the C-13 UBT had sensitivity, specificity, PPV, NPV and accuracy of 96.0%, 84.6%, 92.3%, 91.7% and 92.1%, respectively. The more significant correlation in C-14 than C-13 UBT (r=0.948 vs r=0.819, p<0.001) was found between the value of UBT and the grade of distribution of H. pylori infection. We conclude that the diagnostic performance between C-14 and C-13 UBT to detect H. pylori infection is not significantly different, but the value of C-14 UBT

  18. Study on parameters of L-[1-13C] phenylalanine breath test for quantitative assessment of liver function in healthy subjects and patients with hepatitis B virus-related liver disease

    International Nuclear Information System (INIS)

    Yan Weili; Fudan Univ., Shanghai; Lin Xiangtong; Jiang Yibin; Sun Su; Sun Dayu

    2005-01-01

    The aims of this study are to investigate the feasibility and validity of the L-[1- 13 C] phenylalanine breath test ( 13 C-PheBT) which has been used to measure hepatocyte functional capacity in hepatitis B virus-related liver disease patients and to propose validity parameters of the test in 12 healthy volunteer, 8 chronic hepatitis and 26 liver cirrhotic patients. 100mg/body nonradiative L-[1- 13 C] phenylalanine ( 13 C-Phe) was administered orally to all subjects. Breath samples were taken before and different intervals within 360 min after administration. The 13 CO 2 / 12 CO 2 enrichment was assessed by isotope ratio mass spectrometer( The parameter percentage 13 C excretion rate 13 CERt (% 13 C dose/h) all peaked within 10-30 min after oral 13 C-Phe application)The parameters such as maximum value of 13 C excretion rate, 13 CER max (% 13 C dose/h) (controls: 18.0±3.3; Child A: 11.0±3.8; Child B: 5.0±0.5; Child C: 3.6±1.2), 13 C excretion rate at 30 min, 13 CER 30 (% dose/h) (controls: 11.9±2.1; Child A: 8.1±0.4; Child B: 6.1±0.9; Child C: 3.2±1.2), 13 C cumulative excretion of first 60 min, 13 C cum60 (% 13 C dose) (controls: 9.3±1.4; Child A: 6.6±0.7; Child B: 4.1±0.3; Child C: 2.6±0.9) and half time of 13 C excretion rate, T 1 / 2 (minutes) (controls: 40.4±4.4; chronic hepatitis: 53.4±4.4; Child A: 59.8±4.5; Child B: 102.0±17.3; Child C: 212.1±87.9) were effective indexes which could be employed to stage hepatocyte impairment and liver functional reserve of advanced HBV-related cirrhotic patients (i.e. healthy subjects, Child A, B, C); T 1/2 was also useful for distinguishing mild HBV-related liver injure. (authors)

  19. Study, with the help of nuclear indicators (HTO, Urea 14C and 24Na), of the renewal of water, urea and sodium in different parts of the rat kidney in aqueous diuresis and of the gerbil kidney in osmotic diuresis or in oliguria

    International Nuclear Information System (INIS)

    Lechene, C.P.

    1965-06-01

    In the kidney of the gerbil in oliguria there exists a cortico-papillary gradient in the concentration of the sodium and of the urea; this gradient disappears in the gerbil kidney in osmotic diuresis or in the rat kidney in aqueous diuresis; in these three states of diuresis there is no significant difference in the potassium concentration between the surface and interior regions of the kidneys. Kinetic studies using tritiated water, urea 14 C and 24 Na show that water and urea in the interior regions of the kidney are only renewed very slowly (1 h) whereas the sodium is rapidly changed (1 mn). These results can be explained using WIRZ's theory concerning the mechanism of the counter-current concentration of urine. Furthermore, the evolution of the specific radioactivity of urea 14 C is favorable for a cortical synthesis of urea. (author) [fr

  20. Isotope ratio mass spectrometry (IRMS) versus laser-assisted ratio analyzer (LARA): a comparative study using two doses of.

    Science.gov (United States)

    Savarino, V; Landi, F; Dulbecco, P; Ricci, C; Tessieri, L; Biagini, R; Gatta, L; Miglioli, M; Celle, G; Vaira, D

    2000-11-01

    This study was carried out to compare the measurements and the diagnostic accuracy of the traditional expensive IRMS and the new economical LARA system using two doses of [13C]urea + two different test meals in patients undergoing upper gastrointestinal endoscopy, both before and after anti-Helicobacter treatment. A total of 354 dyspeptic patients underwent endoscopy with gastric biopsies to diagnose H. pylori infection by CLO-test and histology. No patients had taken antibiotics, bismuth, or antisecretory drugs in the 4 weeks before testing. After overnight fasting, breath samples were collected simultaneously in both plastic and glass tubes at baseline and at 30 and 60 min after urea ingestion. In 237 patients 100 mg [13C]urea + Ensure and in 117 patients 75 mg [13C]urea + citric acid were given. The test was also performed with the two urea dosages and meals in 67 and 64 infected patients, respectively, four weeks after anti-Helicobacter therapy. H. pylori was considered eradicated when both biopsy-based tests were negative. A delta value >5 per thousand was considered positive. Breath samples with insufficient CO2 levels at both 30 and 60 min were excluded from final analysis (N = 37 in pre- and N = 8 in posttreatment). There was excellent agreement between overall delta values of the two machines with both [13C]urea 100 mg + Ensure and [13C]urea 75 mg + citric acid. The 95% CI of the difference against the mean was wider with the former (mean -1.3, +6.3, and -9.4) than with the latter urea dosage and test meal (mean -1.2, +5.2 and -8.1). LARA and IRMS were equally effective (P = NS) in distinguishing infected from uninfected patients before therapy using both doses of [13C]urea and test meals (sensitivity ranged from 95% to 99% and specificity from 95% to 97%). This good performance was maintained in the posttreatment phase (sensitivity ranged from 90% to 100% and specificity from 90% to 97%), without any statistical difference among the various combinations

  1. Relationship between postoperative erythromycin breath test and early morbidity in liver transplant recipients

    DEFF Research Database (Denmark)

    Schmidt, Lars E; Rasmussen, Allan; Kirkegaard, Preben

    2003-01-01

    of cyclosporine and tacrolimus nephrotoxicity, episodes of early graft rejection, early graft function, and graft survival. RESULTS: Cyclosporine and tacrolimus nephrotoxicity were associated with low postoperative ERMBT values (mean 0.63%+/-0.25% 14C/hr vs. 1.35%+/-0.84% 14C/hr, P=0.02). No significant...... association between early graft rejection and ERMBT values was demonstrated. There was a significant inverse correlation between postoperative ERMBT values and the time to normalization of international normalized ratio as a measure of early graft function (r=-0.78, PGraft loss was associated......BACKGROUND: Interindividual variability in dosage requirements of the calcineurin inhibitor immunosuppressive agents cyclosporine and tacrolimus after liver transplantation may result from differences in the CYP3A activity of the liver graft. Early postoperative erythromycin breath test (ERMBT...

  2. Synergistic mechanism of combinative application of bensulfuron and urea

    International Nuclear Information System (INIS)

    Yu Liuqing; Huang Shiwen; Zhou Hongjie; Ye Guibiao

    1998-01-01

    Nutrient culture study was initiated to examine the synergistic mechanism of combinative application of bensulfuron and urea for weed control. The absorption of 14 C-bensulfuron and their distribution in Lindernia procumbens (Krock.) Philcox were also investigated to determine the variation between two methods (combinative use of 14 C-bensulfuron plus urea and 14 C-bensulfuron alone). One hour after combinative application of 14 C-bensulfuron plus urea, the highest amount of 14 C-activity in L. procumbens were obtained. However, when 14 C-bensulfuron applied alone, total absorption of 14 C-activity was much lower in the 1st hour and then it slowly increased with time. The distribution of 14 C-bensulfuron in root of L. procumbens plant was the highest and that in leaves was the lowest

  3. Transfer of blood urea into the goat colon

    International Nuclear Information System (INIS)

    Engelhardt, W. von; Hinderer, S.

    1976-01-01

    Transfer of body urea into the temporarily isolated and perfused colon of conscious goats was measured. Simultaneously total urea turnover was estimated using 14 C-urea. The transfer of urea into the total gastrointestinal tract (total turnover minus renal excretion) was four times higher with the high-energy - low-protein diet (sugar pulp plus straw) compared with control feeding (hay ad lib.). The transfer of urea into the colon was 8% of the transfer into the total GI tract during control feeding, 14% when food was withheld for 48 hours and 1% during sugar pulp feeding. The transfer into the colon depends mainly on the plasma urea concentration, whereas in the proximal part of the GI tract changes in the permeability of the GI tract wall have a more pronounced influence than plasma urea concentration. (author)

  4. The relationship of normal body temperature, end-expired breath temperature, and BAC/BrAC ratio in 98 physically fit human test subjects.

    Science.gov (United States)

    Cowan, J Mack; Burris, James M; Hughes, James R; Cunningham, Margaret P

    2010-06-01

    The relationship between normal body temperature, end-expired breath temperature, and blood alcohol concentration (BAC)/breath alcohol concentration (BrAC) ratio was studied in 98 subjects (84 men, 14 women). Subjects consumed alcohol sufficient to produce a BrAC of at least 0.06 g/210 L 45-75 min after drinking. Breath samples were analyzed using an Intoxilyzer 8000 specially equipped to measure breath temperature. Venous blood samples and body temperatures were then taken. The mean body temperature of the men (36.6 degrees C) was lower than the women (37.0 degrees C); however, their mean breath temperatures were virtually identical (men: 34.5 degrees C; women: 34.6 degrees C). The BAC exceeded the BrAC for every subject. BAC/BrAC ratios were calculated from the BAC and BrAC analytical results. There was no difference in the BAC/BrAC ratios for men (1:2379) and women (1:2385). The correlation between BAC and BrAC was high (r = 0.938, p body temperature and end-expired breath temperature, body temperature and BAC/BrAC ratio, and breath temperature and BAC/BrAC ratio were much lower. Neither normal body temperature nor end-expired breath temperature was strongly associated with BAC/BrAC ratio.

  5. Production of granules of urea, urea-ammonium sulphate and urea-potassium chloride enriched with 15N

    International Nuclear Information System (INIS)

    Bendassolli, J.A.

    1991-01-01

    Using a pearling tower it was possible to produce granulated urea, and granulated mixtures of ammonium sulphate and urea, potassium chloride and urea, Labelled in 15 N. Granulated urea with 1, 2, 3 and 4 mm of diameter was obtained using a system with a heating controller. A low concentration of biuret was observed in the granules produced ( 15 N-Labelled ( 15 NH 4' 15 NH 2 ) with variable proportion of ammonium sulphate and urea. (author)

  6. Urea ammoniation compared to urea supplementation as a method ...

    African Journals Online (AJOL)

    Urea ammoniation compared to urea supplementation as a method of improving the nutritive value of wheat straw for sheep. S.W.P. Cloete, N.M. Kritzinger. Winter Rainfall Region, Eisenburg. The ammoniation of wheat straw by urea in a stack method was in- vestigated and compared to urea supplemented and untreated ...

  7. FEV manoeuvre induced changes in breath VOC compositions: an unconventional view on lung function tests

    Science.gov (United States)

    Sukul, Pritam; Schubert, Jochen K.; Oertel, Peter; Kamysek, Svend; Taunk, Khushman; Trefz, Phillip; Miekisch, Wolfram

    2016-06-01

    Breath volatile organic compound (VOC) analysis can open a non-invasive window onto pathological and metabolic processes in the body. Decades of clinical breath-gas analysis have revealed that changes in exhaled VOC concentrations are important rather than disease specific biomarkers. As physiological parameters, such as respiratory rate or cardiac output, have profound effects on exhaled VOCs, here we investigated VOC exhalation under respiratory manoeuvres. Breath VOCs were monitored by means of real-time mass-spectrometry during conventional FEV manoeuvres in 50 healthy humans. Simultaneously, we measured respiratory and hemodynamic parameters noninvasively. Tidal volume and minute ventilation increased by 292 and 171% during the manoeuvre. FEV manoeuvre induced substance specific changes in VOC concentrations. pET-CO2 and alveolar isoprene increased by 6 and 21% during maximum exhalation. Then they decreased by 18 and 37% at forced expiration mirroring cardiac output. Acetone concentrations rose by 4.5% despite increasing minute ventilation. Blood-borne furan and dimethyl-sulphide mimicked isoprene profile. Exogenous acetonitrile, sulphides, and most aliphatic and aromatic VOCs changed minimally. Reliable breath tests must avoid forced breathing. As isoprene exhalations mirrored FEV performances, endogenous VOCs might assure quality of lung function tests. Analysis of exhaled VOC concentrations can provide additional information on physiology of respiration and gas exchange.

  8. Ammonia volatilization from coated urea forms

    Directory of Open Access Journals (Sweden)

    Carlos Antonio Costa do Nascimento

    2013-08-01

    Full Text Available Nitrogen fertilization is a major component of the cost of agricultural production, due to the high cost and low efficiency of fertilizers. In the case of urea, the low efficiency is mainly due to losses by volatilization, which are more pronounced in cultivation systems in which plant residues are left on the soil. The objective of this work was to compare the influence of urea coated with sulfur or boric acid and copper sulfate with conventional N fertilizers on N volatilization losses in sugar cane harvested after stubble burning. The sources urea, sulfur-coated urea, urea coated with boric acid and copper sulfate, as well as nitrate and ammonium sulfate, were tested at amounts containing N rates of 120 kg ha-1 N. The integration of new technologies in urea fertilization can reduce N losses by volatilization. These losses were most reduced when using nitrate and ammonium sulfate. The application of a readily acidified substance (boric acid to urea was more efficient in reducing volatilization losses and nutrient removal by sugar cane than that of a substance with gradual acidification (elemental sulfur.

  9. Isotope-labelled urea to test colon drug delivery devices in vivo : principles, calculations and interpretations

    NARCIS (Netherlands)

    Maurer, Marina; Schellekens, Reinout C. A.; Wutzke, Klaus D.; Stellaard, Frans

    2013-01-01

    This paper describes various methodological aspects that were encountered during the development of a system to monitor the in vivo behaviour of a newly developed colon delivery device that enables oral drug treatment of inflammatory bowel diseases. [C-13]urea was chosen as the marker substance.

  10. Evaluation of eight enzyme immunoassays for detection of immunoglobulin G against Helicobacter pylori

    NARCIS (Netherlands)

    Thijs, JC; Kleibeuker, JH; vanZwet, AA; Berrelkamp, RJP; Meijer, B.C

    Eight commercial enzyme-linked immunosorbent assays (ELISAs) were used to test sera taken from 102 patients in whom Helicobacter pylori infection status had been determined by means of biopsy culture, PCR, histology, and urease production and by C-13 urea breath test. By those means, 61 patients had

  11. Fractionation of nitrogen and carbon isotopes by means of urea chromatography

    International Nuclear Information System (INIS)

    Hirschberg, K.; Krumbiegel, P.; Faust, H.

    1981-01-01

    Between aqueous urea solutions and strongly acid cation exchange resins of the polystyrene-sulfoacid type a solid-liquid-phase distribution equilibrium develops with an isotope effect of nitrogen and carbon in urea. The [ 13 C, 15 N] urea molecules are preferably bound to the exchanger matrix. The elementary separation factors for 15 N and 13 C enrichment have been determined to be 1.00 per cent. Column chromatographic separation with the aid of Dowex 50 WX8 renders the preparation of double-labelled urea feasible. (author)

  12. Nicotine, acetanilide and urea multi-level 2H-, 13C- and 15N-abundance reference materials for continuous-flow isotope ratio mass spectrometry.

    Science.gov (United States)

    Schimmelmann, Arndt; Albertino, Andrea; Sauer, Peter E; Qi, Haiping; Molinie, Roland; Mesnard, François

    2009-11-01

    Accurate determinations of stable isotope ratios require a calibration using at least two reference materials with different isotopic compositions to anchor the isotopic scale and compensate for differences in machine slope. Ideally, the delta values of these reference materials should bracket the isotopic range of samples with unknown delta values. While the practice of analyzing two isotopically distinct reference materials is common for water (VSMOW-SLAP) and carbonates (NBS 19 and L-SVEC), the lack of widely available organic reference materials with distinct isotopic composition has hindered the practice when analyzing organic materials by elemental analysis/isotope ratio mass spectrometry (EA-IRMS). At present only L-glutamic acids USGS40 and USGS41 satisfy these requirements for delta13C and delta15N, with the limitation that L-glutamic acid is not suitable for analysis by gas chromatography (GC). We describe the development and quality testing of (i) four nicotine laboratory reference materials for on-line (i.e. continuous flow) hydrogen reductive gas chromatography-isotope ratio mass-spectrometry (GC-IRMS), (ii) five nicotines for oxidative C, N gas chromatography-combustion-isotope ratio mass-spectrometry (GC-C-IRMS, or GC-IRMS), and (iii) also three acetanilide and three urea reference materials for on-line oxidative EA-IRMS for C and N. Isotopic off-line calibration against international stable isotope measurement standards at Indiana University adhered to the 'principle of identical treatment'. The new reference materials cover the following isotopic ranges: delta2H(nicotine) -162 to -45 per thousand, delta13C(nicotine) -30.05 to +7.72 per thousand, delta15N(nicotine) -6.03 to +33.62 per thousand; delta15N(acetanilide) +1.18 to +40.57 per thousand; delta13C(urea) -34.13 to +11.71 per thousand, delta15N(urea) +0.26 to +40.61 per thousand (recommended delta values refer to calibration with NBS 19, L-SVEC, IAEA-N-1, and IAEA-N-2). Nicotines fill a gap as

  13. Oxidation of urea-derived nitrogen by thaumarchaeota-dominated marine nitrifying communities.

    Science.gov (United States)

    Tolar, Bradley B; Wallsgrove, Natalie J; Popp, Brian N; Hollibaugh, James T

    2017-12-01

    Urea nitrogen has been proposed to contribute significantly to nitrification by marine thaumarchaeotes. These inferences are based on distributions of thaumarchaeote urease genes rather than activity measurements. We found that ammonia oxidation rates were always higher than oxidation rates of urea-derived N in samples from coastal Georgia, USA (means ± SEM: 382 ± 35 versus 73 ± 24 nmol L -1  d -1 , Mann-Whitney U-test p  0.05). Urea-derived N was relatively more important in samples from Antarctic continental shelf waters, though the difference was not statistically significant (19.4 ± 4.8 versus 12.0 ± 2.7 nmol L -1  d -1 , p > 0.05). We found only weak correlations between oxidation rates of urea-derived N and the abundance or transcription of putative Thaumarchaeota ureC genes. Dependence on urea-derived N does not appear to be directly related to pH or ammonium concentrations. Competition experiments and release of 15 NH 3 suggest that urea is hydrolyzed to ammonia intracellularly, then a portion is lost to the dissolved pool. The contribution of urea-derived N to nitrification appears to be minor in temperate coastal waters, but may represent a significant portion of the nitrification flux in Antarctic coastal waters. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  14. News from the Breath Analysis Summit 2011.

    Science.gov (United States)

    Corradi, Massimo; Mutti, Antonio

    2012-06-01

    This special section highlights some of the important work presented at the Breath Analysis Summit 2011, which was held in Parma (Italy) from 11 to 14 September 2011. The meeting, which was jointly organized by the International Association for Breath Research and the University of Parma, was attended by more than 250 delegates from 33 countries, and offered 34 invited lectures and 64 unsolicited scientific contributions. The summit was organized to provide a forum to scientists, engineers and clinicians to present their latest findings and to meet industry executives and entrepreneurs to discuss key trends, future directions and technologies available for breath analysis. A major focus was on nitric oxide, exhaled breath condensate, electronic nose, mass spectrometry and newer sensor technologies. Medical applications ranged from asthma and other respiratory diseases to gastrointestinal disease, occupational diseases, critical care and cancer. Most people identify breath tests with breathalysers used by police to estimate ethanol concentration in blood. However, breath testing has far more sophisticated applications. Breath analysis is rapidly evolving as a new frontier in medical testing for disease states in the lung and beyond. Every individual has a breath fingerprint-or 'breathprint'-that can provide useful information about his or her state of health. This breathprint comprises the many thousands of molecules that are expelled with each breath we exhale. Breath research in the past few years has uncovered the scientific and molecular basis for such clinical observations. Relying on mass spectrometry, we have been able to identify many such unique substances in exhaled breath, including gases, such as nitric oxide (NO) and carbon monoxide (CO), and a wide array of volatile organic compounds. Exhaled breath also carries aerosolized droplets that can be collected as an exhaled breath condensate that contains endogenously produced non-volatile compounds. Breath

  15. The impact of urea-induced unfolding on the redox process of immobilised cytochrome c.

    Science.gov (United States)

    Monari, Stefano; Millo, Diego; Ranieri, Antonio; Di Rocco, Giulia; van der Zwan, Gert; Gooijer, Cees; Peressini, Silvia; Tavagnacco, Claudio; Hildebrandt, Peter; Borsari, Marco

    2010-11-01

    We have studied the effect of urea-induced unfolding on the electron transfer process of yeast iso-1-cytochrome c and its mutant K72AK73AK79A adsorbed on electrodes coated by mixed 11-mercapto-1-undecanoic acid/11-mercapto-1-undecanol self-assembled monolayers. Electrochemical measurements, complemented by surface enhanced resonance Raman studies, indicate two distinct states of the adsorbed proteins that mainly differ with respect to the ligation pattern of the haem. The native state, in which the haem is axially coordinated by Met80 and His18, displays a reduction potential that slightly shifts to negative values with increasing urea concentration. At urea concentrations higher than 6 M, a second state prevails in which the Met80 ligand is replaced by an additional histidine residue. This structural change in the haem pocket is associated with an approximately 0.4 V shift of the reduction potential to negative values. These two states were found for both the wild-type protein and the mutant in which lysine residues 72, 73 and 79 had been substituted by alanines. The analysis of the reduction potentials, the reaction enthalpies and entropies as well as the rate constants indicates that these three lysine residues have an important effect on stabilising the protein structure in the adsorbed state and facilitating the electron transfer dynamics.

  16. Spontaneous breathing test in the prediction of extubation failure in the pediatric population.

    Science.gov (United States)

    Nascimento, Milena Siciliano; Rebello, Celso Moura; Vale, Luciana Assis Pires Andrade; Santos, Érica; Prado, Cristiane do

    2017-01-01

    To assess whether the spontaneous breathing test can predict the extubation failure in pediatric population. A prospective and observational study that evaluated data of inpatients at the Pediatric Intensive Care Unit between May 2011 and August 2013, receiving mechanical ventilation for at least 24 hours followed by extubation. The patients were classified in two groups: Test Group, with patients extubated after spontaneous breathing test, and Control Group, with patients extubated without spontaneous breathing test. A total of 95 children were enrolled in the study, 71 in the Test Group and 24 in the Control Group. A direct comparison was made between the two groups regarding sex, age, mechanical ventilation time, indication to start mechanical ventilation and respiratory parameters before extubation in the Control Group, and before the spontaneous breathing test in the Test Group. There was no difference between the parameters evaluated. According to the analysis of probability of extubation failure between the two groups, the likelihood of extubation failure in the Control Group was 1,412 higher than in the Test Group, nevertheless, this range did not reach significance (p=0.706). This model was considered well-adjusted according to the Hosmer-Lemeshow test (p=0.758). The spontaneous breathing test was not able to predict the extubation failure in pediatric population. Avaliar se o teste de respiração espontânea pode ser utilizado para predizer falha da extubação na população pediátrica. Estudo prospectivo, observacional, no qual foram avaliados todos os pacientes internados no Centro de Terapia Intensiva Pediátrica, no período de maio de 2011 a agosto de 2013, que utilizaram ventilação mecânica por mais de 24 horas e que foram extubados. Os pacientes foram classificados em dois grupos: Grupo Teste, que incluiu os pacientes extubados depois do teste de respiração espontânea; e Grupo Controle, pacientes foram sem teste de respiração espont

  17. Modulation of cadmium-induced phytotoxicity in Cabomba caroliniana by urea involves photosynthetic metabolism and antioxidant status.

    Science.gov (United States)

    Huang, Wenmin; Shao, Hui; Zhou, Sining; Zhou, Qin; Li, Wei; Xing, Wei

    2017-10-01

    Urea is a widespread organic pollutant, which can be a nitrogen source, playing different roles in the growth of submerged macrophytes depending on concentrations, while high cadmium (Cd) concentrations are often toxic to macrophytes. In order to evaluate the combined effect of urea and Cd on a submerged macrophyte, Cabomba caroliniana, the morphological and physiological responses of C. caroliniana in the presence of urea and Cd were studied. The results showed that high concentrations of urea (400mgL -1 ) and Cd (500µmolL -1 ) had negative effects on C. caroliniana. There were strong visible symptoms of toxicity after 4 days of exposure under Cd-alone, 400mgL -1 urea, and Cd+400mgL -1 urea treatments. In addition, 400mgL -1 urea and Cd had adverse effects on C. caroliniana's pigment system. Significant losses in chlorophyll fluorescence and photosynthetic rates, as well as Rubisco activity were also observed under Cd-alone, 400mgL -1 urea, and Cd+400mgL -1 urea treatments. 400mgL -1 urea markedly enhanced Cd toxicity in C. caroliniana, reflected by a sharp decrease in photosynthetic activity and more visible toxicity symptoms. The results of thiobarbituric acid reactive substances (TBARS) pointed to extreme oxidative stress in C. caroliniana induced under Cd or 400mgL -1 urea exposure. Exogenous ascorbate (AsA) protected C. caroliniana from adverse damage in 400mgL -1 urea, which further corroborated the oxidative stress claim under 400mgL -1 urea. However, results also demonstrated that lower urea concentration (10mgL -1 ) alleviated Cd-induced phytotoxicity by stimulating chlorophyll synthesis and photosynthetic activity, as well as activating the activity of catalase (CAT) and glutathione-S-transferase (GST), which may explain the alleviating effect of urea on C. caroliniana under Cd stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Using Nuclear Techniques to Detect Helicobacter Pylori Infection

    International Nuclear Information System (INIS)

    Slater, Christine

    2014-01-01

    Helicobacter pylori (H. pylori) is present in all countries the world over. More than 50% of the world’s population harbour H. pylori in their upper gastrointestinal tract. It can negatively influence nutrition by affecting the uptake of iron and zinc and by increasing susceptibility to diarrhoeal disease. Beyond that, H. pylori is also a major cause of stomach diseases like chronic gastritis, and elevates the risk of developing stomach cancer. The carbon-13 urea breath test is a quick and non-invasive diagnostic test to detect the presence of H. pylori. The patient drinks urea labelled with stable carbon isotopes ( 13 C) that is dissolved in orange juice or citric acid to make sure it coats the entire surface of the stomach, thereby improving the test’s accuracy. If H. pylori is present, it metabolizes the urea and, after 30 minutes, produces carbon dioxide labelled with the stable carbon isotope ( 13 CO 2 ), which can be detected in the breath analysis

  19. Urea metabolism in plants.

    Science.gov (United States)

    Witte, Claus-Peter

    2011-03-01

    Urea is a plant metabolite derived either from root uptake or from catabolism of arginine by arginase. In agriculture, urea is intensively used as a nitrogen fertilizer. Urea nitrogen enters the plant either directly, or in the form of ammonium or nitrate after urea degradation by soil microbes. In recent years various molecular players of plant urea metabolism have been investigated: active and passive urea transporters, the nickel metalloenzyme urease catalyzing the hydrolysis of urea, and three urease accessory proteins involved in the complex activation of urease. The degradation of ureides derived from purine breakdown has long been discussed as a possible additional metabolic source for urea, but an enzymatic route for the complete hydrolysis of ureides without a urea intermediate has recently been described for Arabidopsis thaliana. This review focuses on the proteins involved in plant urea metabolism and the metabolic sources of urea but also addresses open questions regarding plant urea metabolism in a physiological and agricultural context. The contribution of plant urea uptake and metabolism to fertilizer urea usage in crop production is still not investigated although globally more than half of all nitrogen fertilizer is applied to crops in the form of urea. Nitrogen use efficiency in crop production is generally well below 50% resulting in economical losses and creating ecological problems like groundwater pollution and emission of nitric oxides that can damage the ozone layer and function as greenhouse gasses. Biotechnological approaches to improve fertilizer urea usage bear the potential to increase crop nitrogen use efficiency. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  20. Entry of blood urea into the rumen of the llama

    International Nuclear Information System (INIS)

    Hinderer, S.; Engelhardt, W. von

    1976-01-01

    Llamas were provided with a large rumen fistula, and the transfer of blood urea into the temporarily isolated rumen, cleaned and filled with test solution was measured. Plasma urea clearance due to transfer of blood urea across the rumen wall should indicate changes in its permeability to urea. Clearance values were highest with CO 2 or with high concentrations of butyric acid. Permeability was low when food was with-held and when no volatile fatty acids were present in the solution. The permeability of the rumen wall to blood urea can be altered significantly. These changes can affect blood urea transfer more extensively than changes in the plasma urea concentration within physiological ranges

  1. Engineering task plan for determining breathing rates in single shell tanks using tracer gas

    International Nuclear Information System (INIS)

    Andersen, J.A.

    1997-01-01

    The testing of single shell tanks to determine breathing rates. Inert tracer gases helium, and sulfur hexafluoride will be injected into the tanks AX-103, BY-105, C-107 and U-103. Periodic samples will be taken over a three month interval to determine actual headspace breathing rates

  2. A coupled-enzyme equilibrium method for measuring urea in serum: optimization and evaluation of the AACC study group on urea candidate reference method.

    Science.gov (United States)

    Sampson, E J; Baird, M A; Burtis, C A; Smith, E M; Witte, D L; Bayse, D D

    1980-06-01

    We describe a coupled-enzyme equilibrium method for measuring urea in serum, which is performed on supernates prepared by treating each specimen with Ba(OH)2 and ZnSO4 (Somogyi reagent). Analytical recovery of [14C]urea added to a variety of matrices was essentially complete (mean, 100.6%) for the supernates after precipitation. Nine variables were univariately examined in arriving at the reaction conditions for the method: glutamate dehydrogenase, urease, 2-oxoglutarate, ADP, Tris . HCI, NADH, EDTA, pH, and temperature. The reagent is stable for at least 48 days at--20 degrees C and for 23 days at 4 degrees C. Mean analytical recovery of urea (14 mmol/L) added to seven different specimens (three different matrices) was 100.8%. The analytical linear range of the method extends to 30 mmol of urea per liter. Of 22 potential interferents, only bilirubin at 1 mmol/L (580 mg/L), hemoglobin at 10 g/L, and hydroxyurea at 6 mmol/L showed more than 2% interference. We discuss precision and effects of specimen dilution, and compare results for 100 human serum specimens with those measured for the same specimens with four other urea methods. We examined the effects of measuring a blank, consisting of sample and reagent without urease, with each specimen.

  3. BreathDx - molecular analysis of exhaled breath as a diagnostic test for ventilator-associated pneumonia: protocol for a European multicentre observational study

    NARCIS (Netherlands)

    van Oort, Pouline M. P.; Nijsen, Tamara; Weda, Hans; Knobel, Hugo; Dark, Paul; Felton, Timothy; Rattray, Nicholas J. W.; Lawal, Oluwasola; Ahmed, Waqar; Portsmouth, Craig; Sterk, Peter J.; Schultz, Marcus J.; Zakharkina, Tetyana; Artigas, Antonio; Povoa, Pedro; Martin-Loeches, Ignacio; Fowler, Stephen J.; Bos, Lieuwe D. J.; Camprubi, Marta; Coelho, Luis; Davie, Alan; Diaz, Emili; Goma, Gemma; Goodacre, Royston; Leopold, Jan-Hendrik; Rijnders, Guus; Steenwelle, Ruud; Valles, Jordi; Verhoeckx, Fred; Vink, Anton; Winters, Tineke

    2017-01-01

    The diagnosis of ventilator-associated pneumonia (VAP) remains time-consuming and costly, the clinical tools lack specificity and a bedside test to exclude infection in suspected patients is unavailable. Breath contains hundreds to thousands of volatile organic compounds (VOCs) that result from host

  4. Design and implementation of mixing chambers to improve thermal decomposition of urea for NOX abatement

    KAUST Repository

    Lee, Junggil

    2012-10-01

    Urea-selective catalytic reduction (SCR) has been reported as the most promising technique for adherence to NOX emissions regulations. In the urea-SCR process, NH3 is generated by urea thermal decomposition and hydrolysis and is then used as a reductant of NOX in the SCR catalyst. Therefore, improving the NOX conversion efficiency of urea-SCR requires enhancement of thermal decomposition upstream of the SCR catalyst. In the present work, two types of mixing chambers were designed and fabricated to improve urea thermal decomposition, and experiments with and without a mixing chamber were carried out to analyze thermal-decomposition characteristics of urea in the exhaust pipe with respect to inlet velocity (4-12μm/s) and temperature (350°C-500°C). Urea thermal decomposition is greatly enhanced at higher gas temperatures. At an inlet velocity of 6μm/s in the A-type mixing chamber, NH3 concentrations generated along the exhaust pipe were about 171% and 157% greater than those without the mixing chamber for inlet temperatures of 400°C and 500°C, respectively. In the case of the B-type mixing chamber, NH3 concentrations generated at inlet temperatures of 400°C and 500°C were about 147% and 179% greater than those without the mixing chamber, respectively. Note that the implementation of mixing chambers significantly enhanced conversion of urea to NH3 because it increased the residence time of urea in the exhaust pipe and improved mixing between urea and exhaust gas. © 2012, Mary Ann Liebert, Inc.

  5. Inward contaminant leakage tests of the S-Tron Corporation emergency escape breathing device.

    Science.gov (United States)

    1992-04-01

    At the request of S-Tron Corporation, to support their contract with the U.S. Navy, performance tests of the Emergency Escape Breathing Device (EEBD) were conducted in the Environmental Physiology Research Section contaminant leakage chamber. Sulfur ...

  6. Effect of urea supplemented and urea treated straw based diet on milk urea concentration in crossbred Karan-Fries cows

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Sirohi

    2010-01-01

    Full Text Available The study was undertaken to evaluate the effect of urea supplemented and urea treated straw based diet on milk ureaconcentration. Six multiparous crossbred Karan-Fries (Holstein Friesian ✕ Tharparkar cows were blocked into threegroups of nearly equal body weight, DIM, milk yield and milk fat content and were randomized into a 3 ✕ 3 Latin squaredesign with 3-week period. Three experimental diets were fed to the animals. Composition of these diets were: Diet 1green maize, wheat straw and concentrate mixture; Diet 2 green maize, wheat straw, concentrate mixture (urea supplementedand molasses; Diet 3 green maize (4 % of total DM, 4 % urea treated wheat straw and concentrate mixture.Intake of DM and CP did not vary across the diets. Intake of digestible crude protein (DCP was found significantlyhigher in diet 2, while ME and NEL intakes were found significantly lower in diet 3 but did not differ between diets 1and 2. Average milk and plasma urea concentrations (mg dl-1 were found 29.2 ± 2.6, 45.3 ± 0.9, 34.5 ± 2.3 and 28.9± 2.4, 36.6 ± 1.4, 33.9 ± 2.2, respectively in diet 1, diet 2 and diet 3. Urea concentrations in morning milk sampleswere found significantly lower than noon or evening samples in all the three diets. Concentrations of urea in milk andplasma were found closely correlated (r = 0.94 and the regression equation developed was, plasma urea = 8.90 (.89+ .79 (.02 milk urea. Intake (g of DCP than CP, per unit (MCal of ME was found more closely associated with milk ureaconcentration. The study revealed that urea supplementation and urea treated straw based diet increased urea concentrationsignificantly in milk and plasma. Morning milk urea values that estimated at a time gap of 15 hr since last majorfeeding may be considered as the lowest level and can be used for interpretation to monitor feeding adequacy or reproductiveperformances in dairy cows.

  7. Effects of high ambient temperature on urea-nitrogen recycling in lactating dairy cows.

    Science.gov (United States)

    Obitsu, Taketo; Kamiya, Mitsuru; Kamiya, Yuko; Tanaka, Masahito; Sugino, Toshihisa; Taniguchi, Kohzo

    2011-08-01

    Effects of exposure to hot environment on urea metabolism were studied in lactating Holstein cows. Four cows were fed ad libitum a total mixed ration and housed in a temperature-controlled chamber at constant moderate (18°C) or high (28°C) ambient temperatures in a cross-over design. Urea nitrogen (N) kinetics was measured by determining urea isotopomer in urine after single injection of [(15) N(2) ]urea into the jugular vein. Both dry matter intake and milk yield were decreased under high ambient temperature. Intakes of total N and digestible N were decreased under high ambient temperature but urinary urea-N excretion was increased. The ratio of urea-N production to digestible N was increased, whereas the proportion of gut urea-N entry to urea-N production tended to be decreased under high ambient temperature. Neither return to the ornithine cycle, anabolic use nor fecal excretion of urea-N recycled to the gut was affected by ambient temperature. Under high ambient temperature, renal clearance of plasma urea was not affected but the gut clearance was decreased. Increase of urea-N production and reduction of gut urea-N entry, in relative terms, were associated with increased urinary urea-N excretion of lactating dairy cows in higher thermal environments. 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.

  8. Is breath acetone a biomarker of diabetes? A historical review on breath acetone measurements.

    Science.gov (United States)

    Wang, Zhennan; Wang, Chuji

    2013-09-01

    Since the ancient discovery of the 'sweet odor' in human breath gas, pursuits of the breath analysis-based disease diagnostics have never stopped. Actually, the 'smell' of the breath, as one of three key disease diagnostic techniques, has been used in Eastern-Medicine for more than three thousand years. With advancement of measuring technologies in sensitivity and selectivity, more specific breath gas species have been identified and established as a biomarker of a particular disease. Acetone is one of the breath gases and its concentration in exhaled breath can now be determined with high accuracy using various techniques and methods. With the worldwide prevalence of diabetes that is typically diagnosed through blood testing, human desire to achieve non-blood based diabetic diagnostics and monitoring has never been quenched. Questions, such as is breath acetone a biomarker of diabetes and how is the breath acetone related to the blood glucose (BG) level (the golden criterion currently used in clinic for diabetes diagnostic, monitoring, and management), remain to be answered. A majority of current research efforts in breath acetone measurements and its technology developments focus on addressing the first question. The effort to tackle the second question has begun recently. The earliest breath acetone measurement in clearly defined diabetic patients was reported more than 60 years ago. For more than a half-century, as reviewed in this paper, there have been more than 41 independent studies of breath acetone using various techniques and methods, and more than 3211 human subjects, including 1581 healthy people, 242 Type 1 diabetic patients, 384 Type 2 diabetic patients, 174 unspecified diabetic patients, and 830 non-diabetic patients or healthy subjects who are under various physiological conditions, have been used in the studies. The results of the breath acetone measurements collected in this review support that many conditions might cause changes to breath

  9. Distribution and excretion of α-naphthylthio-[14C]urea in Albino rats

    International Nuclear Information System (INIS)

    Patil, T.N.; Radhakrishnamurty, R.

    1977-01-01

    α-naphthylthio-( 14 C) urea was synthesised by allowing potassium ( 14 C)thiocyanate to react with α-naphthylamine. Its distribution and excretion were studied in Albino rats following the administration of this rodenticide. Considerable radioactivity observed in liver and kidney, increased till 8 hr and later decreased. About 80% of the activities present in serum and pleural effusion were found in the respective albumin fractions. Approximately 40% of the dose administered was excreted in urine and less than 1% in faeces in 20 hr. About 36% of the total urinary activity was recovered as unchanged compound and the rest was distributed in three metabolites with low Rsyb(f) values. Decrease in cytochsome P-450 content and activities of N, N-dimethylaniline demethylase, aryl 4-hydroxylase and reduced NAD dehydrogenase were observed in α-naphthylathiourea-treated rats. (author)

  10. N-Urea Efficiency In Lowland Rice Applied With Azolla

    International Nuclear Information System (INIS)

    Rasjid, Havid; Sisworo, E.L.; Wemay, Y.; Sisworo, W.H.

    2000-01-01

    Two N-fertilizer experiments have been conducted using urea tablet and prill urea combined with Azolla application. Twelve treatments have been tested using 2 rice varieties namely Atomita-4 and IR-64. To enable the determination of N-urea efficiency 15 N labelled urea was used. The experiments were conducted in the dry and wet season (DS and WS) 1994/1995 at the experimental station, pusaka negara, Subang West Java. Data obtained from the two experiments showed that the highest N-urea efficiency was found in Atomita-4 applied with urea-tablet (DS=46,1%, WS= 35,8%). Letting the Azolla grow during one lowland rice growth period could increase the N-urea prill efficiency (±5%) compared when no azolla was applied. Apparently Atomita-4 could use N-urea more efficiently compared to IR-64, showing higher grain yield (atomita-4 DS=6.2 ton ha -1 WS=5.9 ton ha -1 ) vs IR-64 (DS=5.8 ton ha -1 , WS=5.3 ton ha -1 ). Decreasing the levels of TSP not influence to the urea efficiency at the DS and WS

  11. Reassessment of primed constant-infusion tracer method to measure urea kinetics

    International Nuclear Information System (INIS)

    Jahoor, F.; Wolfe, R.R.

    1987-01-01

    The validity of the primed constant-infusion tracer technique to make short-term measurements of urea production rates (R/sub a/) in humans in a physiological steady state and during disruption of steady state was evaluated. Four subjects received a primed constant infusion (P/I = 560 min) of [ 13 C]urea for 8 h. A plateau in urea enrichment was reached after 2 h and maintained throughout. When [ 13 C]- and [ 18 O]urea were simultaneously infused into four subjects at P/I ratios of 560:1 and 360:1, respectively, both tracers reached plateau enrichment at the same time (2-4 h). The enrichment at plateau was a function of the infusion rate rather than the priming dose, and calculated urea R/sub a/ was the same with either prime. In five additional experiments the technique responded acutely to a physiological perturbation (alanine infusion) in a dose-dependent manner. The results confirm that this technique is appropriate for short-term measurements of urea R/sub a/, and the requirement for accuracy in estimating the priming dose is not impractically stringent

  12. Urea hydrolysis and ammonia volatilization from some urea based fertilizers applied to rice

    International Nuclear Information System (INIS)

    Misra, C.; Jena, D.; Bandyopadhyay, K.K.; Schepers, J.S.

    1995-01-01

    Field experiments were carried out in replicated microplots (1 m x 1 m) with rice (cv. Pathara) to study urea hydrolysis using several urea based N-fertilizer sources. Results indicated highly significant urea based N-fertilizers, among which urea super granule (USG) and prilled urea (PU) (applied in two splits) could be rated as the most efficient sources of N. Based on measured ammonia volatilization loss, NH 2 -N concentration in flood water and soil solution (following fertilizer application); urea hydrolysis was observed to be faster in the case of PU, USG, PU + ECC (encapsulated calcium carbide) and UNP (urea nitro phosphate) (19-19-0) than in the case of GCU (gypsum coated urea) and UNP (27-9-0) treatments. Based on the 15 N tagged prilled urea experiment, it is observed that about 24 per cent of fertilizer nitrogen was utilized by the crop in closed system as compared to 18 per cent in natural free system. (author). 5 refs., 2 figs., 4 tabs

  13. Leyenda áurea, un código estético al servicio de lo grotesco

    Directory of Open Access Journals (Sweden)

    García Pascual, Raquel

    2005-06-01

    Full Text Available José María Rodríguez Méndez is a well known creator of the Post-Civil War Drama, but his work has not been studied as the whole. The main subject that concern us is to point out that Leyenda áurea, written in 1998, helps us to see how the writer is used to employ a carnivalesque code. Far from his neosainetes Bodas que fueron famosas or Historia de unos cuantos, this piece focus on a new dramatic manner; we'll like to underline the original language its characters display.José María Rodríguez Méndez es un dramaturgo canónico encuadrado en el teatro español de posguerra, pero su obra no ha sido estudiada de forma global. De la mano de Leyenda áurea, escrita en 1998, nos gustaría demostrar cómo su autor ha venido desplegando en sus últimas obras un código carnavalesco. Lejos de sus neosainetes Bodas que fueron famosas o Historia de unos cuantos, esta pieza es una muestra de su nuevo estilo dramático; pretendemos poner de relieve el original uso idiomático que exhiben sus personajes.

  14. State of Motor-Evacuation Function of the Stomach According to 13C-Octanoate Breath Test in Patients with Gastroesophageal Reflux Disease

    Directory of Open Access Journals (Sweden)

    V.G. Mishchuk

    2014-09-01

    Full Text Available We examined 58 patients with erosive form of gastroesophageal reflux disease and 10 healthy volunteers. All patients underwent fibrogastroduodenoscopy, 24 hour pH monitoring in the lower third of esophagus, 13C-octanoate breath test, identified concentration of cholecystokinin-pankreozymin in blood serum. It is found that 44.83 % of patients with gastroesophageal reflux disease have delayed, 36.21 % — rapid and 18.97 % — normal motor-e­vacuation function of the stomach. In patients with delayed gastric motility we observed prevalence of bile reflux with pH over 6 in the lower third of the esophagus, amounting to 42 % (p = 0.044, and increased concentration in the blood of cholecystokinin-pankreozymin up to (7.12 ± 0.21 ng/ml (p < 0.05, in healthy subjects — (5.91 ± 0.34 ng/ml. In patients with accelerated motility number of refluxes under 4 was 45 %, and cholecystokinin-pankreozymin le­vel — (4.4 ± 1.2 ng/ml. These data support the view of other authors that causes of heartburn as a leading symptom of gastroesophageal reflux disease can be duodenogastric reflux and visceral hyperalgesia.

  15. Urea in Milk

    OpenAIRE

    Projectsatbangalore

    2017-01-01

    This paper describes the design of a low-cost, portable instrument using CO2 and NH3 gas sensor technology to quantify and differentiate milk samples containing excess urea. Milk containing urea, in presence of urease enzyme hydrolyses urea to form ammonia and carbon dioxide.

  16. Influence of Continuous Table Motion on Patient Breathing Patterns

    International Nuclear Information System (INIS)

    Wilbert, Juergen; Baier, Kurt; Richter, Anne; Herrmann, Christian; Ma Lei; Flentje, Michael; Guckenberger, Matthias

    2010-01-01

    Purpose: To investigate the influence of continuous table motion on patient breathing patterns for compensation of moving targets by a robotic treatment couch. Methods and Materials: Fifteen volunteers were placed on a robotic treatment couch, and the couch was moved on different breathing-correlated and -uncorrelated trajectories. External abdominal breathing motion of the patients was measured using an infrared camera system. The influence of table motion on breathing range and pattern was analyzed. Results: Continuous table motion was tolerated well by all test persons. Volunteers reacted differently to table motion. Four test persons showed no change of breathing range and pattern. Increased irregular breathing was observed in 4 patients; however, irregularity was not correlated with table motion. Only 4 test persons showed an increase in mean breathing amplitude of more than 2mm during motion of the couch. The mean cycle period decreased by more than 1 s for 2 test persons only. No abrupt changes in amplitude or cycle period could be observed. Conclusions: The observed small changes in breathing patterns support the application of motion compensation by a robotic treatment couch.

  17. Breath biomarkers in toxicology.

    Science.gov (United States)

    Pleil, Joachim D

    2016-11-01

    Exhaled breath has joined blood and urine as a valuable resource for sampling and analyzing biomarkers in human media for assessing exposure, uptake metabolism, and elimination of toxic chemicals. This article focuses current use of exhaled gas, aerosols, and vapor in human breath, the methods for collection, and ultimately the use of the resulting data. Some advantages of breath are the noninvasive and self-administered nature of collection, the essentially inexhaustible supply, and that breath sampling does not produce potentially infectious waste such as needles, wipes, bandages, and glassware. In contrast to blood and urine, breath samples can be collected on demand in rapid succession and so allow toxicokinetic observations of uptake and elimination in any time frame. Furthermore, new technologies now allow capturing condensed breath vapor directly, or just the aerosol fraction alone, to gain access to inorganic species, lung pH, proteins and protein fragments, cellular DNA, and whole microorganisms from the pulmonary microbiome. Future applications are discussed, especially the use of isotopically labeled probes, non-targeted (discovery) analysis, cellular level toxicity testing, and ultimately assessing "crowd breath" of groups of people and the relation to dose of airborne and other environmental chemicals at the population level.

  18. The cholesteryl octanoate breath test: a new procedure for detection of pancreatic insufficiency in the rat.

    Science.gov (United States)

    Mundlos, S; Rhodes, J B; Hofmann, A F

    1987-09-01

    A breath test for the detection of pancreatic insufficiency was developed and tested in rats. The test features the hydrophobic molecule cholesteryl-1-14C-octanoate, which liberates 14C-octanoic acid when hydrolyzed by carboxyl ester lipase (cholesterol esterase). The 14C-octanoate is absorbed passively and rapidly metabolized to 14CO2, which is excreted in expired air. The compound was administered as an emulsion of cholesteryl octanoate, triglyceride, and lecithin to rats with mild pancreatic insufficiency induced by injecting the pancreatic duct with zein. The animals had exocrine pancreatic hypofunction based on the enzyme content of pancreas at autopsy. Amylase was reduced by 97.1 +/- 1.4%, whereas chymotrypsin was reduced by 73 +/- 14%. The p-aminobenzoic acid test was abnormal at 1 wk (21.68 +/- 8.4%), but become normal at 3 months (72.08 +/- 5.8%) after zein injection. Despite this, the animals gained weight and absorbed fat normally. The 14CO2 excretion rate in the 110-min interval after feeding was significantly reduced to 60% of sham-operated animals. Peak 14CO2 collections 20 min after feeding were reduced by 75 +/- 11%. 14CO2 output was completely normalized by administration of pancreatin prior to the test meal. The results suggest that a sensitive, noninvasive method for detecting deficiency of pancreatic carboxyl ester lipase (cholesterol esterase) secretion in the rat has been developed.

  19. Quantifying why urea is a protein denaturant, whereas glycine betaine is a protein stabilizer

    Science.gov (United States)

    Guinn, Emily J.; Pegram, Laurel M.; Capp, Michael W.; Pollock, Michelle N.; Record, M. Thomas

    2011-01-01

    To explain the large, opposite effects of urea and glycine betaine (GB) on stability of folded proteins and protein complexes, we quantify and interpret preferential interactions of urea with 45 model compounds displaying protein functional groups and compare with a previous analysis of GB. This information is needed to use urea as a probe of coupled folding in protein processes and to tune molecular dynamics force fields. Preferential interactions between urea and model compounds relative to their interactions with water are determined by osmometry or solubility and dissected using a unique coarse-grained analysis to obtain interaction potentials quantifying the interaction of urea with each significant type of protein surface (aliphatic, aromatic hydrocarbon (C); polar and charged N and O). Microscopic local-bulk partition coefficients Kp for the accumulation or exclusion of urea in the water of hydration of these surfaces relative to bulk water are obtained. Kp values reveal that urea accumulates moderately at amide O and weakly at aliphatic C, whereas GB is excluded from both. These results provide both thermodynamic and molecular explanations for the opposite effects of urea and glycine betaine on protein stability, as well as deductions about strengths of amide NH—amide O and amide NH—amide N hydrogen bonds relative to hydrogen bonds to water. Interestingly, urea, like GB, is moderately accumulated at aromatic C surface. Urea m-values for protein folding and other protein processes are quantitatively interpreted and predicted using these urea interaction potentials or Kp values. PMID:21930943

  20. Urea metabolism in Zebu calves fed on diets of dierent crude protein contents

    International Nuclear Information System (INIS)

    Sharma, P.K.; Singh, U.B.; Verma, D.N.; Lal, M.; Ranjhan, S.K.

    1974-01-01

    The entry rates of urea into the body pool of urea have been estimated in Zebu calves using a single injection isotope dilution technique using 14 C-urea. The excretion rates of urea were calculated by estimating total urine over 24 h and urea content. The calves were fed 2 levels of crude protein, i.e., 25 percent lower and 25 percent higher than NRC recommendations. Results show that the degradation of urea is significantly better in animals given rations low in crude protein contents. (M.G.B.)

  1. Walk test and school performance in mouth-breathing children.

    Science.gov (United States)

    Boas, Ana Paula Dias Vilas; Marson, Fernando Augusto de Lima; Ribeiro, Maria Angela Gonçalves de Oliveira; Sakano, Eulália; Conti, Patricia Blau Margosian; Toro, Adyléia Dalbo Contrera; Ribeiro, José Dirceu

    2013-01-01

    In recent decades, many studies on mouth breathing (MB) have been published; however, little is known about many aspects of this syndrome, including severity, impact on physical and academic performances. Compare the physical performance in a six minutes walk test (6MWT) and the academic performance of MB and nasal-breathing (NB) children and adolescents. This is a descriptive, cross-sectional, and prospective study with MB and NB children submitted to the 6MWT and scholar performance assessment. We included 156 children, 87 girls (60 NB and 27 MB) and 69 boys (44 NB and 25 MB). Variables were analyzed during the 6MWT: heart rate (HR), respiratory rate, oxygen saturation, distance walked in six minutes and modified Borg scale. All the variables studied were statistically different between groups NB and MB, with the exception of school performance and HR in 6MWT. MB affects physical performance and not the academic performance, we noticed a changed pattern in the 6MWT in the MB group. Since the MBs in our study were classified as non-severe, other studies comparing the academic performance variables and 6MWT are needed to better understand the process of physical and academic performances in MB children.

  2. Radiation-induced polymerization of 1, 3-butadiene in urea canal complex as studied by broad line NMR

    International Nuclear Information System (INIS)

    Yoshii, Fumio; Hayakawa, Naohiro; Abe, Toshihiko

    1975-01-01

    Dependence of the NMR spectrum on the molar ratio of 1,3-butadiene to urea, temperature dependence of the spectrum and changes of the spectrum during polymerization were observed. The results were discussed in comparison with previously reported results for the canal polymerization of acrylonitrile and vinyl chloride. 1,3-butadiene formes a canal complex with the molar ratio of 1 to 4 for 1,3-butadiene to urea. The urea canal complex is decomposed at -15 0 C. The spectrum of 1,3-butadiene in urea canal complex shows existence of a remarkably mobile component which was not observed on the spectra of acrylonitrile - urea of vinyl chloride - urea canal complex. The line width of 1,3-butadiene in the urea canal complex except the very narrow component was broader than that for vinyl chloride in the urea canal complex over an observed temperature range. The line width of urea formed the canal decreases at lower temperature than those of urea in vinyl chloride - urea canal complex. The post-polymerization of 1,3-butadiene in the urea canal complex started clearly from -78 0 C and completes when the temperature was raised to 20 0 C. The polymerization will be proceeded by the such way that monomer molecules move to the active center in the canal, as considered in the case of the polymerization of acrylonitrile and vinyl chloride in the canal complex. The crystal structure of the urea canal was maintained during polymerization and than the polybutadiene - urea canal complex was necessarily formed after the polymerization. The formation of the polymer - urea canal complex has distinct difference between 1,3-butadiene and acrylonitrile or vinyl chloride. For acrylonitrile and vinyl chloride the canals around the polymer formed are destroyed. The structure of polybutadiene - urea canal complex was hexagonal having a=8.21, c=10.50 A. (auth.)

  3. Influence of urea application on growth, yield and mineral uptake in ...

    African Journals Online (AJOL)

    A pot experiment was conducted in a wire netting green house in order to assess the beneficial effect of urea on corn cultivars (C-20 and C-79) differing in yield production. Corn plants were grown in loam soil with alkaline in reaction. Application of varying urea levels did not change the physico-chemical properties of soil.

  4. Audit of Helicobacter pylori Testing in Microbiology Laboratories in England: To Inform Compliance with NICE Guidance and the Feasibility of Routine Antimicrobial Resistance Surveillance

    Directory of Open Access Journals (Sweden)

    Rosalie Allison

    2016-01-01

    Full Text Available Introduction. The National Institute for Health and Clinical Excellence (NICE guidance recommends that dyspeptic patients are tested for Helicobacter pylori using a urea breath test, stool antigen test, or serology. Antibiotic resistance in H. pylori is globally increasing, but treatment in England is rarely guided by susceptibility testing or surveillance. Aims. To determine compliance of microbiology laboratories in England with NICE guidance and whether laboratories perform culture and antibiotic susceptibility testing (AST. Methods. In 2015, 170 accredited English microbiology laboratories were surveyed, by email. Results. 121/170 (71% laboratories responded; 96% provided H. pylori testing (78% on site. 94% provided H. pylori diagnosis using stool antigen; only four provided serology as their noninvasive test; 3/4 of these encouraged urea breath tests in their acute trusts. Only 22/94 (23% of the laboratories performed H. pylori cultures from gastric biopsies on site; 9/22 performed AST, but the vast majority processed less than one specimen/week. Conclusions. Only five laboratories in England do not comply with NICE guidance; these will need the guidance reinforced. National surveillance needs to be implemented; culture-based AST would need to be centralised. Moving forward, detection of resistance in H. pylori from stool specimens using molecular methods (PCR needs to be explored.

  5. C-130J Breathing Resistance Study

    Science.gov (United States)

    2016-05-01

    scientific and technical information exchange , and its publication does not constitute the Government’s approval or disapproval of its ideas or findings...regulator and MBU- 20/P oxygen mask, was supplied gaseous Aviators’ Breathing Oxygen (ABO). The regulator was operated in various operating modes, at...Generating System (OBOGS) Laboratory, Area B, Wright-Patterson AFB OH. The CRU-73 oxygen regulator was supplied with 50 pounds/square inch of gaseous

  6. Urea metabolism in buffalo calves fed on rations containing two levels of crude protein

    International Nuclear Information System (INIS)

    Verma, D.N.; Singh, U.B.; Lal, M.; Varma, A.; Ranjhan, S.K.

    1974-01-01

    Urea entry rates into the body pools of Murrah Buffalo calves have been estimated using a single injection isotope dilution technique using 14 C-urea. The animals were fed two levels of crude proteins, namely, 13 percent lower and 19 percent higher than N.R.C. recommendations. Results show that the recycling of urea is significantly better in animals given low crude protein contents. (M.G.B.)

  7. 1,1′-Binaphthyl-2,2′-dicarboxylic acid–urea (1/1

    Directory of Open Access Journals (Sweden)

    Edwin Weber

    2008-10-01

    Full Text Available In the title co-crystal, C22H14O4·CH4N2O, the 1,1′-binaphthyl-2,2′-dicarboxylic acid (BNDA and urea molecules are connected via a system of hydrogen bonds into a chiral two-dimensional polymeric structure parallel to the (001 plane. As the crystal is centrosymmetric, it consists of alternately stacked BNDA–urea layers of opposite chirality. The urea H atoms trans to the C=O group are bonded in a chelating mode [R12(6] to the carbonyl O atom from one of the carboxylic acid groups which, in turn, acts as the donor of an O—H...O hydrogen bond to another urea molecule. The [010] chains thus formed are further connected via an R22(8 hydrogen-bond motif formed between urea and the second carboxylic acid group of BNDA.

  8. Radiation-induced changes in breathing frequency and lung histology of C57BL/6J mice are time- and dose-dependent

    Energy Technology Data Exchange (ETDEWEB)

    Eldh, T.; Heinzelmann, F.; Velalakan, A. [Univ. Hospital of Tuebingen (Germany). Dept. of Radiation Oncology; Budach, W. [Duesseldorf Univ. (Germany). Dept. of Radiation Oncology; Belka, C. [Univ. Hospital of Tuebingen (Germany). Dept. of Radiation Oncology; Muenchen Univ. (Germany). Dept. of Radiation Oncology; Jendrossek, V. [Univ. Hospital of Tuebingen (Germany). Dept. of Radiation Oncology; Duisburg-Essen Univ., Essen (DE). Inst. of Cell Biology (Cancer Research)

    2012-03-15

    Pneumonitis and fibrosis constitute serious adverse effects of radiotherapy in the thoracic region. In this study, time-course and dose-dependence of clinically relevant parameters of radiation-induced lung injury in C57BL/6J mice were analyzed. A well-characterized disease model is necessary for the analysis of the cellular and molecular mechanisms using genetically modified mice. C57BL/6J mice received single dose right hemithorax irradiation with 12.5 or 22.5 Gy. Body weight and breathing frequency were recorded as parameters for health impairment. Lung tissue was collected over 24 weeks for histological analysis. Hemithorax irradiation with 12.5 or 22.5 Gy induced biphasic breathing impairment with the first increase between days 7 and 70. Although breathing impairment was more pronounced in the 22.5 Gy group, it was accompanied in both dose groups by pneumonitis-associated histological changes. A second rise in breathing frequency ratios became visible starting on day 70 with a steady increase until day 210. Again, breathing was more strongly affected in the 22.5 Gy group. However, breathing impairment coincided only in the 22.5 Gy group with a significant increase in collagen deposition in the lung tissue by day 210. Tissue inflammation and fibrosis were observed in the irradiated and the shielded lungs, pointing toward involvement of systemic effects. Hemithorax irradiation induces time-dependent pneumonitis and fibrosis in C57BL/6J mice. While hemithorax irradiation with 12.5 Gy is sufficient to induce lung inflammation, it is below the threshold for collagen deposition and fibrosis development by day 210.

  9. Design and testing of an independently controlled urea SCR retrofit system for the reduction of NOx emissions from marine diesels.

    Science.gov (United States)

    Johnson, Derek R; Bedick, Clinton R; Clark, Nigel N; McKain, David L

    2009-05-15

    Diesel engine emissions for on-road, stationary and marine applications are regulated in the United States via standards set by the Environmental Protection Agency (EPA). A major component of diesel exhaust that is difficult to reduce is nitrogen oxides (NOx). Selective catalytic reduction (SCR) has been in use for many years for stationary applications, including external combustion boilers, and is promising for NOx abatement as a retrofit for mobile applications where diesel compression ignition engines are used. The research presented in this paper is the first phase of a program focused on the reduction of NOx by use of a stand-alone urea injection system, applicable to marine diesel engines typical of work boats (e.g., tugs). Most current urea SCR systems communicate with engine controls to predict NOx emissions based on signals such as torque and engine speed, however many marine engines in use still employ mechanical injection technology and lack electronic communication abilities. The system developed and discussed in this paper controls NOx emissions independentof engine operating parameters and measures NOx and exhaust flow using the following exhaust sensor inputs: absolute pressure, differential pressure, temperature, and NOx concentration. These sensor inputs were integrated into an independent controller and open loop architecture to estimate the necessary amount of urea needed, and the controller uses pulse width modulation (PWM) to power an automotive fuel injector for airless urea delivery. The system was tested in a transient test cell on a 350 hp engine certified at 4 g/bhp-hr of NOx, with a goal of reducing the engine out NOx levels by 50%. NOx reduction capabilities of 41-67% were shown on the non road transient cycle (NRTC) and ICOMIA E5 steady state cycles with system optimization during testing to minimize the dilute ammonia slip to cycle averages of 5-7 ppm. The goal of 50% reduction of NOx can be achieved dependent upon cycle. Further

  10. EXPERIMENTAL INVESTIGATION OF HEAT STORAGE CHARACTERISTIC OF UREA AND BORAX SALT GRADIENT SOLAR PONDS

    Directory of Open Access Journals (Sweden)

    Hüseyin KURT

    2006-03-01

    Full Text Available Salt gradient solar ponds are simple and low cost solar energy system for collecting and storing solar energy. In this study, heat storage characteristic of urea and borax solutions in the solar pond were examined experimentally. Establishing density gradients in different concentration, variations in the temperature and density profiles were observed in four different experiments. Maximum storage temperatures were measured as 28ºC and 36 ºC for the ponds with urea and borax solution, respectively. The temperature difference between the bottom and the surface of the pond were measured as 13 ºC for urea and 17 ºC for borax- solutions. According to these results, heat storage characteristic of the solar pond with borax solution was found to be better than urea solution.

  11. Frequency of helicobacter pylori infection using /sup 13/C-UBT in asymptomatic individuals of Barakaho, Islamabad, Pakistan

    International Nuclear Information System (INIS)

    Rasheed, F.; Ahmad, T.; Bilal, R.

    2011-01-01

    High frequency of Helicobacter (H.) pylori infection has been reported in Pakistan mainly for dyspeptic patients, while the published data is inadequate regarding asymptomatic population. The non-invasive /sup 13/C urea breath test (UBT) was used to determine the frequency of H. pylori infection in 516 asymptomatic individuals and to find out its association with gender and age. Overall prevalence was 74.4% (384/516) while 63.5% (113/178) children were positive for 13C-UBT and the percentage increased with age in both the genders with significantly higher prevalence in adolescents (p=0.003) and adults (p < 0.001). Moreover, there was non-significant difference between the prevalence of H. pylori infection in males and females in all age categories. The reported high frequency of H. pylori infection warrants further studies to identify epidemiological and environmental risk factors. (author)

  12. Training in multiple breath washout testing for respiratory physiotherapists.

    Science.gov (United States)

    O'Neill, Katherine; Elborn, J Stuart; Tunney, Michael M; O'Neill, Philip; Rowan, Stephen; Martin, Susan; Bradley, Judy M

    2018-03-01

    The development of multiple breath washout (MBW) testing in respiratory disease highlights the need for increased awareness amongst respiratory physiotherapists and a potential opportunity for professional development in the use of an important outcome measure for clinical trials. To rationalise how MBW may be a useful assessment tool for respiratory physiotherapists and to describe a local MBW training and certification programme for physiotherapists. The respiratory Multidisciplinary Team in the Belfast Health and Social Care Trust (BHSCT) identified a need for MBW testing to be available to facilitate clinical research and assessment. A 2day training programme consisting of prereading preparation, self-directed learning, theory presentations, practical demonstrations and hands-on practice was developed and delivered. All participants underwent a certification process. We have demonstrated the successful training and certification of clinical and research physiotherapists and encourage other respiratory physiotherapists to consider MBW test training. Copyright © 2017 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

  13. Effects of breathing frequency and flow rate on the total inward leakage of an elastomeric half-mask donned on an advanced manikin headform.

    Science.gov (United States)

    He, Xinjian; Grinshpun, Sergey A; Reponen, Tiina; McKay, Roy; Bergman, Michael S; Zhuang, Ziqing

    2014-03-01

    The objective of this study was to investigate the effects of breathing frequency and flow rate on the total inward leakage (TIL) of an elastomeric half-mask donned on an advanced manikin headform and challenged with combustion aerosols. An elastomeric half-mask respirator equipped with P100 filters was donned on an advanced manikin headform covered with life-like soft skin and challenged with aerosols originated by burning three materials: wood, paper, and plastic (polyethylene). TIL was determined as the ratio of aerosol concentrations inside (C in) and outside (C out) of the respirator (C in/C out) measured with a nanoparticle spectrometer operating in the particle size range of 20-200nm. The testing was performed under three cyclic breathing flows [mean inspiratory flow (MIF) of 30, 55, and 85 l/min] and five breathing frequencies (10, 15, 20, 25, and 30 breaths/min). A completely randomized factorial study design was chosen with four replicates for each combination of breathing flow rate and frequency. Particle size, MIF, and combustion material had significant (P plastic aerosol produced higher mean TIL values than wood and paper aerosols. The effect of the breathing frequency was complex. When analyzed using all combustion aerosols and MIFs (pooled data), breathing frequency did not significantly (P = 0.08) affect TIL. However, once the data were stratified according to combustion aerosol and MIF, the effect of breathing frequency became significant (P plastic combustion aerosol. The effect of breathing frequency on TIL is less significant than the effects of combustion aerosol and breathing flow rate for the tested elastomeric half-mask respirator. The greatest TIL occurred when challenged with plastic aerosol at 30 l/min and at a breathing frequency of 30 breaths/min.

  14. Hydration of urea and alkylated urea derivatives

    Science.gov (United States)

    Kaatze, Udo

    2018-01-01

    Compressibility data and broadband dielectric spectra of aqueous solutions of urea and some of its alkylated derivatives have been evaluated to yield their numbers Nh of hydration water molecules per molecule of solute. Nh values in a broad range of solute concentrations are discussed and are compared to hydration numbers of other relevant molecules and organic ions. Consistent with previous results, it is found that urea differs from other solutes in its unusually small hydration number, corresponding to just one third of the estimated number of nearest neighbor molecules. This remarkable hydration behavior is explained by the large density φH of hydrogen bonding abilities offered by the urea molecule. In terms of currently discussed models of reorientational motions and allied dynamics in water and related associating liquids, the large density φH causes a relaxation time close to that of undisturbed water with most parts of water encircling the solute. Therefore only a small part of disturbed ("hydration") water is left around each urea molecule. Adding alkyl groups to the basic molecule leads to Nh values which, within the series of n-alkylurea derivatives, progressively increase with the number of methyl groups per solute. With n-butylurea, Nh from dielectric spectra, in conformity with many other organic solutes, slightly exceeds the number of nearest neighbors. Compared to such Nh values, hydration numbers from compressibility data are substantially smaller, disclosing incorrect assumptions in the formula commonly used to interpret the experimental compressibilities. Similar to other series of organic solutes, effects of isomerization have been found with alkylated urea derivatives, indicating that factors other than the predominating density φH of hydrogen bond abilities contribute also to the hydration properties.

  15. Urea biosensor for hemodialysis monitoring

    Science.gov (United States)

    Glass, Robert S.

    1999-01-01

    An electrochemical sensor capable of detecting and quantifying urea in fluids resulting from hemodialysis procedures. The sensor is based upon measurement of the pH change produced in an aqueous environment by the products of the enzyme-catalyzed hydrolysis of urea. The sensor may be fabricated using methods amenable to mass fabrication, resulting in low-cost sensors and thus providing the potential for disposable use. In a typical application, the sensor could be used in treatment centers, in conjunction with an appropriate electronics/computer system, in order to determine the hemodialysis endpoint. The sensor can also be utilized to allow at-home testing to determine if dialysis was necessary. Such a home monitor is similar, in principle, to devices used for blood glucose testing by diabetics, and would require a blood droplet sample by using a finger prick.

  16. Effects of Exogenous Lactase Administration on Hydrogen Breath Excretion and Intestinal Symptoms in Patients Presenting Lactose Malabsorption and Intolerance

    Directory of Open Access Journals (Sweden)

    Ivan Ibba

    2014-01-01

    Full Text Available Objective. To establish whether supplementation with a standard oral dose of Beta-Galactosidase affects hydrogen breath excretion in patients presenting with lactose malabsorption. Methods. Ninety-six consecutive patients positive to H2 Lactose Breath Test were enrolled. Mean peak H2 levels, the time to reach the peak H2, the time to reach the cut-off value of 20 ppm, the cumulative breath H2 excretion, the areas under the curve, and a Visual Analogical 10-point Scale for symptoms were calculated. Genotyping of the C/T-13910 variant was carried out. Results. Following the oral administration of Beta-Galactosidase, in 21.88% of the cases, H2 Lactose Breath Test became negative (Group A, while mean peak H2 levels (74.95 ppm versus 7.85, P<0.0000, in 17.71% (Group B were still positive, with the H2 level 20 ppm above the baseline, but the peak H2 levels were significantly lower than those observed at the baseline test (186.7 ppm versus 66.64, P<0.0000, while in 60.41% (Group C they were still positive with the peak H2 levels similar to those observed at the baseline test (94.43 versus 81.60 ppm. All 96 individuals tested presented the C/C-13910 genotype nonpersistence. Conclusions. The response to oral administration of Beta-Galactosidase in patients with symptoms of lactose malabsorption presents a significant variability.

  17. Cheyne-Stokes respiration: hypoxia plus a deep breath that interrupts hypoxic drive, initiating cyclic breathing.

    Science.gov (United States)

    Guntheroth, Warren G

    2011-11-01

    hypoxic drive, and the cycle of C-SR continues until the next large breath. This novel theory, that a pulse of oxygen interrupts hypoxic drive to cause the initiating apnea of C-SR, is compatible with the known causes of C-SR: onset of sleep, mild hypoxia with congestive heart failure, and neurologic disorders. It is also compatible with factors known to abolish C-SR: waking, oxygen supplementation, and drugs that increase alertness such as caffeine. Testing of the hypothesis would require beat by beat recording of respiration, and arterial oxygen with a response time fast enough to demonstrate the rapid suppression of hypoxic drive. Alternatively, using a different theoretical approach such as limit-cycle oscillators instead of control theory. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Urea-SCR Temperature Investigation for NOx Control of Diesel Engine

    Directory of Open Access Journals (Sweden)

    Asif Muhammad

    2015-01-01

    Full Text Available SCR (selective catalytic reduction system is continuously being analyzed by many researchers worldwide on various concerns due to the stringent nitrogen oxides (NOx emissions legislation for heavy-duty diesel engines. Urea-SCR includes AdBlue as urea source, which subsequently decomposes to NH3 (ammonia being the reducing agent. Reaction temperature is a key factor for the performance of urea-SCR system, as urea decomposition rate is sensitive to a specific temperature range. This particular study was directed to investigate the temperature of the SCR system in diesel engine with the objective to confirm that whether the appropriate temperature is attained for occurrence of urea based catalytic reduction or otherwise and how the system performs on the prescribed temperature range. Diesel engine fitted with urea-SCR exhaust system has been operated on European standard cycle for emission testing to monitor the temperature and corresponding nitrogen oxides (NOx values on specified points. Moreover, mathematical expressions for approximation of reaction temperature are also proposed which are derived by applying energy conservation principal and gas laws. Results of the investigation have shown that during the whole testing cycle system temperature has remained in the range where urea-SCR can take place with best optimum rate and the system performance on account of NOx reduction was exemplary as excellent NOx conversion rate is achieved. It has also been confirmed that selective catalytic reduction (SCR is the best suitable technology for automotive engine-out NOx control.

  19. 13C- and 15N-labelled non-biogenic compounds used as stable isotope drugs for human liver function tests

    International Nuclear Information System (INIS)

    Krumbiegel, P.

    1989-01-01

    As a result of liver diseases, the elimination of certain drugs is retarded. After labelling a suitable drug with 13 C, the 13 CO 2 elimination rate serves as a liver function parameter. Current contributions to the 13 CO 2 breath test method are reviewed and related to the 14 CO 2 breath test proposals. In spite of several advantages of 13 C-labelled agents, some dissatisfaction has remained with the tests, especially at using them with infants. It is the necessity of face masks and the uncertainty to consider endogeneous CO 2 contributions diluting the exhaled 13 CO 2 . The problems are avoided if the other molecule site of the drug is labelled which is known to be eliminated via urine. With 15 N as a tracer, a suitable urine test using [ 15 N]-methacetin as agent has been proposed and put into practice. (author)

  20. Effect of urea on the photoactivity of titania powder prepared by sol-gel method

    International Nuclear Information System (INIS)

    Cheng Ping; Deng Changsheng; Gu Mingyuan; Dai Xiaming

    2008-01-01

    The synthesis of nanocrystalline titania powders from the hydrolysis of Ti(OBu n ) 4 in the presence of urea was investigated. DRS results showed that a redshift occurred in the absorption edge of titania with increasing the content of urea. XRD results indicated that urea showed a retarding effect on the transformation of titania from anatase to rutile. Moreover, the addition of urea resulted in a higher Brunauer-Emmett-Teller (BET) surface area as well as a larger average pore size of TiO 2 nanoparticles. The average pore size of urea/TiO 2 gels calcined at 500 deg. C increased with the increase of urea content, while the specific surface area increased with the amount of urea to reach a maximum at 10% and then decreased with further increase of the amount of urea. The maximal specific surface area of 64.4 m 2 g -1 was obtained for 10% urea/TiO 2 gels calcined at 500 deg. C, which showed an average particle size of 15 nm and pore size distribution in the range of mesopores centered at 5.8 nm. The photocatalytic experiments exhibited that titania nanoparticles prepared in the presence of urea could effectively photodegrade methyl orange under visible light irradiation due to the redshift of the absorption edge. The maximum photoactivity was achieved when the content of urea was 10%, which was attributed to the higher specific surface area

  1. Performance evaluation of an air-breathing high-temperature proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Wu, Qixing; Li, Haiyang; Yuan, Wenxiang; Luo, Zhongkuan; Wang, Fang; Sun, Hongyuan; Zhao, Xuxin; Fu, Huide

    2015-01-01

    Highlights: • An air-breathing HT-PEMFC was designed and evaluated experimentally. • The peak power density of the air-breathing HT-PEMFC was 220.5 mW cm"−"2 at 200 °C. • Break-in behavior and effects of temperature and anodic stoichiometry were studied. • The effect of cell orientations on the performance was investigated. • The degradation rate of the air-breathing HT-PEMFC was around 58.32 μV h"−"1. - Abstract: The air-breathing proton exchange membrane fuel cell (PEMFC) is of great interest in mobile power sources because of its simple system design and low parasitic power consumption. Different from previous low-temperature air-breathing PEMFCs, a high-temperature PEMFC with a phosphoric acid doped polybenzimidazole (PBI) membrane as the polymer electrolyte is designed and investigated under air-breathing conditions. The preliminary results show that a peak power density of 220.5 mW cm"−"2 at 200 °C can be achieved without employing any water managements, which is comparable to those with conventional Nafion® membranes operated at low temperatures. In addition, it is found that with the present cell design, the limiting current density arising from the oxygen transfer limitation is around 700 mA cm"−"2 even at 200 °C. The short-term durability test at 200 mA cm"−"2 and 180 °C reveals that all the cells exhibit a gradual decrease in the voltage along with a rise in the internal resistance. The degradation rate of continuous operation is around 58.32 μV h"−"1, which is much smaller than those of start/stop cycling operations.

  2. Photoluminescence of urea- and urea/rhodamine B-capped TiO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalo-Juan, I., E-mail: gonzalo@materials.tu-darmstadt.de; Macé, L.; Tengeler, S.; Mosallem, A.; Nicoloso, N.; Riedel, R.

    2016-07-01

    Urea- and rhodamine B (RhB)-capped TiO{sub 2} nanoparticles (NPs) have been prepared by solvothermal synthesis and characterized by HRTEM, XRD, FTIR, XPS, optical absorption and photoemission. The urea and urea/RhB ligands are capped to the surface of the TiO{sub 2} NPs for the first time through carbamate bonding. The band gap of TiO{sub 2} is slightly reduced from 3.1 eV to 3.0 eV in the urea capped TiO{sub 2} NPs (TU) and 2.9 eV for the NPs capped with urea/RhB (TUR). The generation of new trapping states in TU and TUR at the conduction band edges (surface oxygen vacancies) has been confirmed by the Urbach law providing tail state energies of 180 meV and 270 meV, respectively. These tail states are considered to be responsible for the strong reduction of the photoluminescence at ≈400 nm and the increased emission at ≈600 nm in TU and TUR. The findings suggest that urea- and RhB-capped TiO{sub 2} NPs could have potential applications as photocatalysts, opto-electronic devices, sensors, biological labels and anti-bacterial agents. - Highlights: • Urea- and urea/rhodamine B (RhB)-capped TiO{sub 2} nanoparticles preparation. • Characterization of optical properties of urea- and urea/rhodamine B (RhB)-capped TiO{sub 2} nanoparticles. • The recombination of electrons and holes is significantly reduced in the capped TiO{sub 2} nanoparticles, in comparison with TiO{sub 2}.

  3. Effects of urea foliar application and of ammonium sulphate and urea applied to the soil on yield and N utilization by beans (Phaseolus vulgaris L.)

    International Nuclear Information System (INIS)

    Muraoka, T.; Victoria, R.L.; Oliveira, J.P.; Boaretto, A.E.

    1984-01-01

    The effects of nitrogen applied to the soil (as ammonium sulphate and urea) and foliar application of urea supplementing or not the soil application, on bean yield and nitrogen utilization are studied in a cerrado soil. Labelled ammonium sulphate is applied at the rate of 20Kg N/ha at seeding or 15 or 25 days after seeding and 40 Kg N/ha at seeding or in two different applications. Labelled urea is applied at the rate of 20kg N/ha at seeding and 40 Kg N/ha splitted. Foliar application is done at 15,22, 29,36 and 45 days after seeding, with 2% urea solution labelled with 10% 15 N. (M.A.C.) [pt

  4. The endemiology of helicobacter pylorus infection and gastro-intestinal disease in mine and related factory workers of Tongling city, Anhui

    International Nuclear Information System (INIS)

    He Xiangyang; Jiang Zhonglin; Yang Shunqi; Mei Yanyan; Wen Qin; Cheng Yingzi; Wang Jianmiao

    2006-01-01

    Objective: To investigate the endemiology of H. pylorus infection and related gastro-intestinal disease in mine and factory workers of Tong-Ling area. Methods: 14 C-urea breath test, serum IgG and cytotoxin-producing H. pylorus antibodies determinations were performed in 1076 randomly selected adults among the mine and related factory workers in Tong - Ling area. Gastroscopy was done in 156 subjects (cytotoxin-producing H. pylorus antibody CagA-HP positive 108 and Cag-HP negative 48). Results: Seven hundred and twenty-one subjects of the 1076 (67.0%) examined were positive with the 14 C-urea breath and serological tests, among which 350 (48.5% of the 721 ) were Cag-HP positive. Factors affecting positiveness of HP infection were in the order of: working environment, gastro-intestinal symptoms, past history, vocation, age, history of previous contact, sex and non- hygiene life-style. Conclusion: The HP infection rate in Tong-Ling area was slightly higher than nationwide but with a lower CagA - HP positive rate. HP infection was mostly related to the working environment and life-style. (authors)

  5. Chemistry of the uranyl group. VI. Complexes of uranyl with hexamethylphosphoramide and urea

    Energy Technology Data Exchange (ETDEWEB)

    Zarli, B; Dall' olio, G; Sindellari, L [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi

    1976-01-01

    Some uranyl complexes with hexamethylphosphoramide (HMPA) and urea were prepared and characterized. The compounds with the former ligand have the general formula UO/sub 2/X/sub 2/.HMPA (where X = (C/sub 2/H/sub 5/)/sub 2/NCSe/sub 2//sup -/, (C/sub 2/H/sub 5/)/sub 2/NCS/sub 2//sup -/ or CH/sub 3/COO/sup -/). For the acetato derivatives a dimeric acetato-bridged structure is suggested. Some properties of UO/sub 2/(NO/sub 3/)/sub 2/.2(HMPA) are also described. With the latter ligand, in addition to the complexes UO/sub 2/(NO/sub 3/)/sub 2/.2urea and (UO/sub 2/(urea)/sub 4/(H/sub 2/0))(NO/sub 3/)/sub 2/ already known, the novel complexes UO/sub 2/(pycrate)/sub 2/.4urea and (UO/sub 2/(CH/sub 3/COO)/sub 2/.urea)sub(n) (where n is probably 2) have been prepared. All attempts to obtain urea complexes of uranyl diethyldithio- or diethyldiselenocarbamate failed and only adducts of unsatisfactory stoichiometry were isolated.

  6. A 15N study on dietary urea utility in young pigs fed with a low protein diet

    International Nuclear Information System (INIS)

    Niiyama, Masayoshi; Kagota, Katsumoto; Iwase, Toshio; Namioka, Shigeo

    1978-01-01

    To investigate effect of a low protein diet on urea utilization, a tracer study was conducted with 15 N-urea on pigs fed a low protein diet (DCP 5.7%) with 2% urea (group B), and on pigs fed and optimal protein diet (DCP 13.3%) with 2% urea (group A). 15 N was incorporated into protein of liver, serum and muscle, which were obtained 8 days after the last administration of 15 N-urea. The 15 N incorporation rate into the tissue protein tended to be higher in group B than in group A. Approximately 70% of 15 N, however, was excreted into urine within 48 hours in group B. A comparison was made on growth and urea level in blood and urine to evaluate efficacy of the administered urea on growth between group B pigs and pigs fed the same low protein diet without urea supplementation (group C). Since group B pigs always maintained a higher level of blood urea, they were considered to have had more ammonia nitrogen which was available for protein synthesis than group C animals. A similar amount of urea to ingested dose, however, was excessively eliminated in urine. The increased ammonia nitrogen by urea ingestion may be excreted in form of urinary urea in group B pigs. There was no difference in growth between group B and group C animals; therefore, poor efficacy of administered urea on growth may have resulted not only from its loss into urine in early stage after ingestion, but also to poor utility of ammonia for protein synthesis. (author)

  7. Urea recycling in ruminants

    International Nuclear Information System (INIS)

    Ohara, Yoshiaki; Niibayashi, Tsunekazu

    1980-01-01

    The transfer of blood urea into the alimentary tract of goats, as ruminants, was studied by the use of 15 N-urea, 15 N-ammonium chloride and physiological experimental techniques. Blood urea after an intravenous injection of 15 N-urea appeared in the first rumen via two routes, the saliva (approximately 60% of the serum urea concentration) and idrect diffusion from the wall of the first rumen, both as the ammonium-form N. The serum urea levels from diets containing different protein levels were paralleled with the protein levels, the ammonium level in the first rumen being similar to that of the serum urea. The transfer of low protein into the NH 3 pool of the first rumen was 56% of the total NH 3 in the entire alimentary tract, and the quantitative ratio of salivary secretion of diffusion in the first rumen was 1:9. The transfer of high protein was 14% in the entire alimentary tract, and the ratio of saliva to diffusion in the first rumen was 6:1. Thus, when protein uptake was large, salivary secretion was the primary route to the first rumen. Approximately 50% of the entire quantity of blood urea in the alimentary tract appeared in the first rumen, and 35%, in the lower alimentary tract, primarily in the duodenum and jejunum. (Chiba, N.)

  8. Final report of the safety assessment of Urea.

    Science.gov (United States)

    2005-01-01

    as 2000 mg/kg in acute oral studies using female rats or mice. No signs of toxicity were observed in male piglets dosed orally with up to 4 g/kg Urea for 5 days. Dogs dosed orally with 5 to 30 g/L Urea for 4 to 10 days had signs of toxicity, including weakness, anorexia, vomiting and retching, diarrhea and a decreased body temperature, which led to a deep torpor or coma. No significant microscopic changes were observed in the skin of male nude mice dermally exposed to 100% Urea for 24 h. No observable effect on fetal development was seen in rats and mice dosed orally with an aqueous solution of Urea (2000 mg/kg) on days 10 and 12 of gestation. The mean number of implants, live fetuses, percent fetal resorptions, mean fetal weight, and percent fetuses malformed were comparable to control group. A detergent containing 15% Urea was injected into pregnant ICR-JCl mice and dams and fetuses had no significant differences when compared to control animals. Urea given orally did not enhance the developmental toxicity of N-nitrosomethylurea. Female Sprague-Dawley rats injected in the uterine horn with 0.05 ml Urea on day 3 (preimplantation) or on day 7 (post implantation) exhibited no maternal mortality or morbidity; a dose-dependent reduction in embryo survival was seen with preimplantation treatment. Urea injected intra-amniotically induces mid-trimester abortions in humans. Urea was not genotoxic in several bacterial and mammalian assays; although in assays where Urea was used at a high concentration, genotoxicity was found, many in in vitro assays. Urea is commonly used in studies of DNA because it causes uncoiling of DNA molecules. Urea was not carcinogenic in Fisher 344 rats or C57B1/6 mice fed diets containing up to 4.5% Urea. Exposure of normal human skin to 60% Urea produced no significant irritation in one study, but 5% Urea was slightly irritating and 20% Urea was irritating in other reports. Burning sensations are the most frequently reported effect of Urea used

  9. Modeling of flux, binding and substitution of urea molecules in the urea transporter dvUT.

    Science.gov (United States)

    Zhang, Hai-Tian; Wang, Zhe; Yu, Tao; Sang, Jian-Ping; Zou, Xian-Wu; Zou, Xiaoqin

    2017-09-01

    Urea transporters (UTs) are transmembrane proteins that transport urea molecules across cell membranes and play a crucial role in urea excretion and water balance. Modeling the functional characteristics of UTs helps us understand how their structures accomplish the functions at the atomic level, and facilitates future therapeutic design targeting the UTs. This study was based on the crystal structure of Desulfovibrio vulgaris urea transporter (dvUT). To model the binding behavior of urea molecules in dvUT, we constructed a cooperative binding model. To model the substitution of urea by the urea analogue N,N'-dimethylurea (DMU) in dvUT, we calculated the occupation probability of DMU along the urea pore and the ratio of the occupation probabilities of DMU at the external (S ext ) and internal (S int ) binding sites, and we established the mutual substitution rule for binding and substitution of urea and DMU. Based on these calculations and modelings, together with the use of the Monte Carlo (MC) method, we further modeled the urea flux in dvUT, equilibrium urea binding to dvUT, and the substitution of urea by DMU in the dvUT. Our modeling results are in good agreement with the existing experimental functional data. Furthermore, the modelings have discovered the microscopic process and mechanisms of those functional characteristics. The methods and the results would help our future understanding of the underlying mechanisms of the diseases associated with impaired UT functions and rational drug design for the treatment of these diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. A nanomaterial-based breath test for distinguishing gastric cancer from benign gastric conditions.

    Science.gov (United States)

    Xu, Z-q; Broza, Y Y; Ionsecu, R; Tisch, U; Ding, L; Liu, H; Song, Q; Pan, Y-y; Xiong, F-x; Gu, K-s; Sun, G-p; Chen, Z-d; Leja, M; Haick, H

    2013-03-05

    Upper digestive endoscopy with biopsy and histopathological evaluation of the biopsy material is the standard method for diagnosing gastric cancer (GC). However, this procedure may not be widely available for screening in the developing world, whereas in developed countries endoscopy is frequently used without major clinical gain. There is a high demand for a simple and non-invasive test for selecting the individuals at increased risk that should undergo the endoscopic examination. Here, we studied the feasibility of a nanomaterial-based breath test for identifying GC among patients with gastric complaints. Alveolar exhaled breath samples from 130 patients with gastric complaints (37 GC/32 ulcers / 61 less severe conditions) that underwent endoscopy/biopsy were analyzed using nanomaterial-based sensors. Predictive models were built employing discriminant factor analysis (DFA) pattern recognition, and their stability against possible confounding factors (alcohol/tobacco consumption; Helicobacter pylori) was tested. Classification success was determined (i) using leave-one-out cross-validation and (ii) by randomly blinding 25% of the samples as a validation set. Complementary chemical analysis of the breath samples was performed using gas chromatography coupled with mass spectrometry. Three DFA models were developed that achieved excellent discrimination between the subpopulations: (i) GC vs benign gastric conditions, among all the patients (89% sensitivity; 90% specificity); (ii) early stage GC (I and II) vs late stage (III and IV), among GC patients (89% sensitivity; 94% specificity); and (iii) ulcer vs less severe, among benign conditions (84% sensitivity; 87% specificity). The models were insensitive against the tested confounding factors. Chemical analysis found that five volatile organic compounds (2-propenenitrile, 2-butoxy-ethanol, furfural, 6-methyl-5-hepten-2-one and isoprene) were significantly elevated in patients with GC and/or peptic ulcer, as compared

  11. Substitution of lucerne hay by untreated, urea-enriched and urea ...

    African Journals Online (AJOL)

    Wheat straw was left untreated (WS), enriched with 1.5% urea (UWS), or ammoniated with 5.5% urea in a stack for 8 .... nitrogen concentration for maximal microbial synthesis is in ... faeces and urine samples were taken daily and pooled for.

  12. Sensing the effects of mouth breathing by using 3-tesla MRI

    Science.gov (United States)

    Park, Chan-A.; Kang, Chang-Ki

    2017-06-01

    We investigated the effects of mouth breathing and typical nasal breathing on brain function by using blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI). The study had two parts: the first test was a simple contrast between mouth and nasal breathing, and the second test involved combined breathing modes, e.g., mouth inspiration and nasal expiration. Eleven healthy participants performed the combined breathing task while undergoing 3T fMRI. In the group-level analysis, contrast images acquired by using an individual participantlevel analysis were processed using the one-sample t test. We also conducted a region-of-interest analysis comparing signal intensity changes between the breathing modes; the region was selected using an automated anatomical labeling map. The results demonstrated that the BOLD signal in the hippocampus and brainstem was significantly decreased in mouth breathing relative to nasal breathing. On the other hand, both the precentral and postcentral gyri showed activation that was more significant in mouth breathing compared to nasal breathing. This study suggests that the BOLD activity patterns between mouth and nasal breathing may be induced differently, especially in the hippocampus, which could provide clues to explain the effects on brain cognitive function due to mouth breathing.

  13. Random breath testing in Australia: getting it to work according to specifications.

    Science.gov (United States)

    Homel, R

    1993-01-01

    After reading the deterrence literature, particularly the work of H. Laurence Ross, I concluded in the late 1970's that many road accidents could be prevented through the wholehearted implementation of random breath testing (RBT). RBT is a system of drink-drive law enforcement which aims to increase the perceived likelihood of apprehension through the use of mass breath testing techniques at roadblocks which are highly visible, are unpredictable in their locations and give the impression of ubiquity. As the result of public pressure, RBT was introduced in NSW in December 1982, with spectacular results. The law was intensively enforced and extensively advertised, partly due to the advocacy of researchers such as myself, but also because ther was an acute political need for instant results. Since RBT is a difficult enforcement technique for police to sustain in effective form, researchers must strive to improve their understanding of what works, and remain in close contact with police, policy makers and politicians. Although this process is costly in terms of time and, possibly, academic 'pay-off', it is essential if the fragile understanding of deterrence principles amongst these groups is not to lead to superficially attractive, but probably ineffective techniques such as low visibility mobile RBT.

  14. /sup 15/N study on dietary urea utility in young pigs fed with a low protein diet

    Energy Technology Data Exchange (ETDEWEB)

    Niiyama, M; Kagota, K; Iwase, T; Namioka, S [Hokkaido Univ., Sapporo (Japan)

    1978-10-01

    To investigate effect of a low protein diet on urea utilization, a tracer study was conducted with /sup 15/N-urea on pigs fed a low protein diet (DCP 5.7%) with 2% urea (group B), and on pigs fed and optimal protein diet (DCP 13.3%) with 2% urea (group A). /sup 15/N was incorporated into protein of liver, serum and muscle, which were obtained 8 days after the last administration of /sup 15/N-urea. The /sup 15/N incorporation rate into the tissue protein tended to be higher in group B than in group A. Approximately 70% of /sup 15/N, however, was excreted into urine within 48 hours in group B. A comparison was made on growth and urea level in blood and urine to evaluate efficacy of the administered urea on growth between group B pigs and pigs fed the same low protein diet without urea supplementation (group C). Since group B pigs always maintained a higher level of blood urea, they were considered to have had more ammonia nitrogen which was available for protein synthesis than group C animals. A similar amount of urea to ingested dose, however, was excessively eliminated in urine. The increased ammonia nitrogen by urea ingestion may be excreted in form of urinary urea in group B pigs. There was no difference in growth between group B and group C animals; therefore, poor efficacy of administered urea on growth may have resulted not only from its loss into urine in early stage after ingestion, but also to poor utility of ammonia for protein synthesis.

  15. Passive water and urea permeability of a human Na(+)-glutamate cotransporter expressed in Xenopus oocytes

    DEFF Research Database (Denmark)

    Macaulay, Nanna; Gether, Ulrik; Klærke, Dan Arne

    2002-01-01

    to the K(0.5) value for glutamate activation of transport. The specific inhibitor DL-threo-beta-benzyloxyaspartate (TBOA) reduced the EAAT1-specific L(p) to 72 %. EAAT1 supported passive fluxes of [(14)C]urea and [(14)C]glycerol. The [(14)C]urea flux was increased in the presence of glutamate. The data...... suggest that the permeability depends on the conformational equilibrium of the EAAT1. At positive potentials and in the presence of Na(+) and glutamate, the pore is enlarged and water and urea penetrate more readily. The L(p) was larger when measured with urea or glycerol as osmolytes as compared...... with mannitol. Apparently, the properties of the pore are not uniform along its length. The outer section may accommodate urea and glycerol in an osmotically active form, giving rise to larger water fluxes. The physiological role of EAAT1 for water homeostasis in the central nervous system is discussed....

  16. Hydrogen bonding of formamide, urea, urea monoxide and their thio

    Indian Academy of Sciences (India)

    Ab initio and DFT methods have been employed to study the hydrogen bonding ability of formamide, urea, urea monoxide, thioformamide, thiourea and thiourea monoxide with one water molecule and the homodimers of the selected molecules. The stabilization energies associated with themonohydrated adducts and ...

  17. A comparison of blood alcohol levels as determined by breath and blood tests taken in actual field operations.

    Science.gov (United States)

    1972-01-01

    During its 1972 session, the General Assembly of Virginia enacted Senate Bill 104, which authorizes the breath test, as well as the blood test used previously, as a proper chemical test to determine the alcoholic content of the blood. Any person arre...

  18. Detection of Helicobacter pylori infection by examination of human breath odor using electronic nose Bloodhound-214ST

    Science.gov (United States)

    Shnayder, E. P.; Moshkin, M. P.; Petrovskii, D. V.; Shevela, A. I.; Babko, A. N.; Kulikov, V. G.

    2009-05-01

    Our aim was to examine the possibility of use e-nose Bloodhound-214ST to determine presence or absence of H. pylori infection using exhalation samples of patients. Breath samples were collected twice: at baseline and after oral administration of 500 mg of urea. H. pylori status of patients was confirmed by antral biopsy. Using two approaches for the data analysis we showed the possibility to distinguish H. pylori free and infected patients.

  19. Urea retranslocation from senescing Arabidopsis leaves is promoted by DUR3-mediated urea retrieval from leaf apoplast

    Science.gov (United States)

    Bohner, Anne; Kojima, Soichi; Hajirezaei, Mohammad; Melzer, Michael; von Wirén, Nicolaus

    2015-01-01

    In plants, urea derives either from root uptake or protein degradation. Although large quantities of urea are released during senescence, urea is mainly seen as a short-lived nitrogen (N) catabolite serving urease-mediated hydrolysis to ammonium. Here, we investigated the roles of DUR3 and of urea in N remobilization. During natural leaf senescence urea concentrations and DUR3 transcript levels showed a parallel increase with senescence markers like ORE1 in a plant age- and leaf age-dependent manner. Deletion of DUR3 decreased urea accumulation in leaves, whereas the fraction of urea lost to the leaf apoplast was enhanced. Under natural and N deficiency-induced senescence DUR3 promoter activity was highest in the vasculature, but was also found in surrounding bundle sheath and mesophyll cells. An analysis of petiole exudates from wild-type leaves revealed that N from urea accounted for >13% of amino acid N. Urea export from senescent leaves further increased in ureG-2 deletion mutants lacking urease activity. In the dur3 ureG double insertion line the absence of DUR3 reduced urea export from leaf petioles. These results indicate that urea can serve as an early metabolic marker for leaf senescence, and that DUR3-mediated urea retrieval contributes to the retranslocation of N from urea during leaf senescence. PMID:25440717

  20. Distribution and excretion of. cap alpha. -naphthylthio-(/sup 14/C)urea in Albino rats

    Energy Technology Data Exchange (ETDEWEB)

    Patil, T N; Radhakrishnamurty, R [Central Food Technological Research Inst., Mysore (India)

    1977-09-01

    ..cap alpha..-naphthylthio-(/sup 14/C) urea was synthesised by allowing potassium (/sup 14/C)thiocyanate to react with ..cap alpha..-naphthylamine. Its distribution and excretion were studied in Albino rats following the administration of this rodenticide. Considerable radioactivity observed in liver and kidney, increased till 8 hr and later decreased. About 80% of the activities present in serum and pleural effusion were found in the respective albumin fractions. Approximately 40% of the dose administered was excreted in urine and less than 1% in faeces in 20 hr. About 36% of the total urinary activity was recovered as unchanged compound and the rest was distributed in three metabolites with low Rsyb(f) values. Decrease in cytochsome P-450 content and activities of N, N-dimethylaniline demethylase, aryl 4-hydroxylase and reduced NAD dehydrogenase were observed in ..cap alpha..-naphthylathiourea-treated rats.

  1. The effect of conditioning agents on the corrosive properties of molten urea

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, D E; Nguyen, D T; Norton, M M; Parker, B R; Daniels, L E

    1991-01-01

    From the process case histories of the failure of several heat exchanger tube bundles, it was revealed that molten urea containing lignosulfonate as a granulation conditioning-hardening agent (Urea LS[trademark]) is corrosive to Types 304 and 316 stainless steel. The results of field and laboratory immersion corrosion tests indicated that the corrosivity of molten urea is strongly dependent on the process temperature rather than the conditioner composition. At temperatures below 295F, molten Urea LS[trademark] is not aggressive to these stainless steels. However, at temperatures above 300F, the corrosion of these stainless steels is extremely severe. The corrosion rate of Types 304, 304L, 316, and 316L is as high as hundreds of mils per year. The corrosion mechanism tends to be more general than localized. The results of the laboratory corrosion test also revealed that among alloying elements, copper is detrimental to corrosion resistance of stainless steel exposed to molten Urea LS[trademark], chromium is the most beneficial, and nickel has only a minor effect. Thus, copper-free and chromium stainless steels have superior corrosion resistance to the molten Urea LS[trademark] at a wide range of temperatures up to 345F.

  2. Breathing adapted radiotherapy for breast cancer: comparison of free breathing gating with the breath-hold technique

    DEFF Research Database (Denmark)

    Korreman, Stine Sofia; Pedersen, Anders N; Nøttrup, Trine Jakobi

    2005-01-01

    BACKGROUND AND PURPOSE: Adjuvant radiotherapy after breast-conserving surgery for breast cancer implies a risk of late cardiac and pulmonary toxicity. This is the first study to evaluate cardiopulmonary dose sparing of breathing adapted radiotherapy (BART) using free breathing gating......, and to compare this respiratory technique with voluntary breath-hold. PATIENTS AND METHODS: 17 patients were CT-scanned during non-coached breathing manoeuvre including free breathing (FB), end-inspiration gating (IG), end-expiration gating (EG), deep inspiration breath-hold (DIBH) and end-expiration breath......-hold (EBH). The Varian Real-time Position Management system (RPM) was used to monitor respiratory movement and to gate the scanner. For each breathing phase, a population based internal margin (IM) was estimated based on average chest wall excursion, and incorporated into an individually optimised three...

  3. Silicone Doped Chitosan-Acrylamide Coencapsulated Urea Fertilizer: An Approach to Controlled Release Fertilizers

    Directory of Open Access Journals (Sweden)

    Sempeho Ibahati Siafu

    2017-01-01

    Full Text Available In the absence of special management practices, urea is known to undergo chemical transformations resulting in severe losses (≈60–70% of total fertilizer applied. In an attempt to design urea controlled release fertilizers in order to counterbalance the 60–70% loss, urea was cross-linked with chitosan and acrylamide under refluxed in situ copolymerization technique; the procedures were repeated with silicone doping prior cross-linking with MBA. The particles were characterized with FTIR/ATR, EDX, XRD, and SEM. The IR bands observed within 3426–409 cm−1 revealed the formation of new bands after coencapsulation for the νγN-H, νβN-H, νOH, νsNH2, νCH2, νC=O, δ′NH2, νC=C, δNH2, νC-N, βCH3, $C-N, γNH2, νC=O, and $CH2. Crystallinity indices for urea with and without silicone doping were found to be 50.9% and 72.1%, respectively, with a distinctive split peak at (d 12.30°. The formation of Microdunes and Microballs 3D network sized 0.64 μm was noted. Release profiles demonstrated that 80% N was released in a period of 30 days at RT and pH 7. The release patterns exhibited linear and deformed sigmoid release models. Empirically, the findings demonstrated that it is possible to design urea controlled release fertilizers with varying particle sizes and morphologies by using chitosan-acrylamide coencapsulation.

  4. Relationship between plasma uridine and urinary urea excretion.

    Science.gov (United States)

    Ka, Tuneyoshi; Inokuchi, Taku; Tamada, Daisuke; Suda, Michio; Tsutsumi, Zenta; Okuda, Chihiro; Yamamoto, Asako; Takahashi, Sumio; Moriwaki, Yuji; Yamamoto, Tetsuya

    2010-03-01

    To investigate whether the concentration of uridine in plasma is related to the urinary excretion of urea, 45 healthy male subjects with normouricemia and normal blood pressure were studied after providing informed consent. Immediately after collection of 24-hour urine, blood samples were drawn after an overnight fast except for water. The contents of ingested foods during the 24-hour urine collection period were described by the subjects and analyzed by a dietician. Simple regression analysis showed that plasma uridine was correlated with the urinary excretions of urea (R = 0.41, P urea. These results suggest that an increase in de novo pyrimidine synthesis leads to an increased concentration of uridine in plasma via nitrogen catabolism in healthy subjects with normouricemia and normal blood pressure. (c) 2010 Elsevier Inc. All rights reserved.

  5. 1-(o-Tol­yl)thio­urea

    Science.gov (United States)

    Corrêa, Rodrigo S.; Ribeiro, Leandro; Ellena, Javier; Estévez-Hernández, Osvaldo; Duque, Julio

    2008-01-01

    In the title compound, C8H10N2S, the o-tolyl group and the thio­urea core are planar. The mean planes of the two groups are almost perpendicular [82.19 (8)°]. The thio­urea group is in the thio­amide form, in which resonance is present. In the crystal structure, mol­ecules are linked by inter­molecular N—H⋯S hydrogen bonds, forming two infinite chains parallel to the (110) and (10) planes. PMID:21201662

  6. Design and implementation of mixing chambers to improve thermal decomposition of urea for NOX abatement

    KAUST Repository

    Lee, Junggil; Kim, Youngdeuk; Kim, Wooseung

    2012-01-01

    to improve urea thermal decomposition, and experiments with and without a mixing chamber were carried out to analyze thermal-decomposition characteristics of urea in the exhaust pipe with respect to inlet velocity (4-12μm/s) and temperature (350°C-500°C

  7. Influence of milk urea concentration on fractional urea disappearance rate from milk to blood plasma in dairy cows.

    Science.gov (United States)

    Spek, J W; Dijkstra, J; Bannink, A

    2016-05-01

    The relationship between milk urea nitrogen (MUN; mg of N/dL) and urinary N excretion is affected, among others, by diurnal dynamics in MUN, which in turn is largely influenced by feed intake pattern and characteristics of urea transfer from blood plasma to milk and vice versa. This study aimed to obtain insight in urea transfer characteristics within the mammary gland and from the mammary gland to blood plasma in dairy cows at various concentrations of plasma urea nitrogen (PUN; mg of N/dL) and MUN. Urea transfer from milk to blood plasma and urea transfer within the mammary gland itself was evaluated in a 4×4 Latin square design using 4 lactating multiparous Holstein-Friesian cows (milk production of 39.8±4.70kg/d and 90±3.9 d in milk). Treatments consisted of 4 primed continuous intravenous urea infusions of 0, 5, 10, and 15g of urea/h. Boluses of [(15)N(15)N]urea were injected in cistern milk at 20, 60, and 100 min before the 1700h milking. Milk was collected in portions of approximately 2 L at the 1700h milking. Milk samples were analyzed for urea and enrichment of (15)N-urea. Results from one cow were discarded because of leakage of milk from the teats after injection of boluses of [(15)N(15)N]urea. Increasing urea infusion rate linearly increased PUN from 11.4 (0g of urea/h) to 25.9mg/dL (15g of urea/h) and MUN from 10.3 (0g of urea/h) to 23.5 (15g of urea/h) mg of N/dL. The percentage of injected [(15)N(15)N]urea recovered from milk at the time of injection was not affected by urea infusion rate and varied between 65.1 and 73.0%, indicating that a substantial portion of injected [(15)N(15)N]urea was not accounted for by collected milk. The estimated fractional disappearance rate of (15)N-urea from milk to blood (Kurea; per hour) linearly increased from 0.429 (0g of urea/h) to 0.641 per hour (15g of urea/h). Cistern injected [(15)N(15)N]urea diffused within 20 min after injection toward alveoli milk. Calculations with the average Kurea estimated in this

  8. The interdependence of excitation and inhibition for the control of dynamic breathing rhythms.

    Science.gov (United States)

    Baertsch, Nathan Andrew; Baertsch, Hans Christopher; Ramirez, Jan Marino

    2018-02-26

    The preBötzinger Complex (preBötC), a medullary network critical for breathing, relies on excitatory interneurons to generate the inspiratory rhythm. Yet, half of preBötC neurons are inhibitory, and the role of inhibition in rhythmogenesis remains controversial. Using optogenetics and electrophysiology in vitro and in vivo, we demonstrate that the intrinsic excitability of excitatory neurons is reduced following large depolarizing inspiratory bursts. This refractory period limits the preBötC to very slow breathing frequencies. Inhibition integrated within the network is required to prevent overexcitation of preBötC neurons, thereby regulating the refractory period and allowing rapid breathing. In vivo, sensory feedback inhibition also regulates the refractory period, and in slowly breathing mice with sensory feedback removed, activity of inhibitory, but not excitatory, neurons restores breathing to physiological frequencies. We conclude that excitation and inhibition are interdependent for the breathing rhythm, because inhibition permits physiological preBötC bursting by controlling refractory properties of excitatory neurons.

  9. Effect of yogic breathing on accommodate braille version of six-letter cancellation test in students with visual impairment

    Directory of Open Access Journals (Sweden)

    Balaram Pradhan

    2018-01-01

    Full Text Available Context: Attentional processes tend to be less well developed in the visually impaired, who require special training to develop them fully. Yogic breathing which alters the patterns of respiration has been shown to enhance attention skills. Letter cancellation tests are well-established tools to measure attention and attention span. Here, a modified Braille version of the six-letter cancellation test (SLCT was used for students with visual impairment (VI. Aim: This study aimed to assess the immediate effects of Bhramari Pranayama (BhPr and breath awareness (BA on students with VI. Methods: This study was a self-as-control study held on 2 consecutive days, on 19 participants (8 males, 11 females, with a mean age of 15.89 ± 1.59 years, randomized into two groups. On the 1st day, Group 1 performed 10 min breath awareness and Group 2 performed Bhramari; on the 2nd day, practices were reversed. Assessments used a SLCT specially adapted for the visually impaired before and after each session. Results: The Braille letter cancellation test was successfully taken by 19 students. Scores significantly improved after both techniques for each student following practices on both days (P < 0.001. BhPr may have more effect on attention performance than BA as wrong scores significantly increased following BA (P < 0.05, but the increase in the score after Bhramari was not significant. Conclusions: Despite the small sample size improvement in attentional processes by both yoga breathing techniques was robust. Attentional skills were definitely enhanced. Long-term practice should be studied.

  10. Effect of Yogic Breathing on Accommodate Braille Version of Six-letter Cancellation Test in Students with Visual Impairment.

    Science.gov (United States)

    Pradhan, Balaram; Mohanty, Soubhagyalaxmi; Hankey, Alex

    2018-01-01

    Attentional processes tend to be less well developed in the visually impaired, who require special training to develop them fully. Yogic breathing which alters the patterns of respiration has been shown to enhance attention skills. Letter cancellation tests are well-established tools to measure attention and attention span. Here, a modified Braille version of the six-letter cancellation test (SLCT) was used for students with visual impairment (VI). This study aimed to assess the immediate effects of Bhramari Pranayama (BhPr) and breath awareness (BA) on students with VI. This study was a self-as-control study held on 2 consecutive days, on 19 participants (8 males, 11 females), with a mean age of 15.89 ± 1.59 years, randomized into two groups. On the 1 st day, Group 1 performed 10 min breath awareness and Group 2 performed Bhramari ; on the 2 nd day, practices were reversed. Assessments used a SLCT specially adapted for the visually impaired before and after each session. The Braille letter cancellation test was successfully taken by 19 students. Scores significantly improved after both techniques for each student following practices on both days ( P < 0.001). BhPr may have more effect on attention performance than BA as wrong scores significantly increased following BA ( P < 0.05), but the increase in the score after Bhramari was not significant. Despite the small sample size improvement in attentional processes by both yoga breathing techniques was robust. Attentional skills were definitely enhanced. Long-term practice should be studied.

  11. An evaluation of twelve nested models of transperitoneal transport of urea

    DEFF Research Database (Denmark)

    Graff, J; Fugleberg, S; Joffe, P

    1995-01-01

    the mechanism(s) of transperitoneal urea transport and to test the one-compartment assumption for urea. A total of 12 nested models were formulated and validated on the basis of experimental results obtained from 23 non-diabetic patients undergoing peritoneal dialysis. The validation procedure demonstrated...

  12. Ammonia as a respiratory gas in water and air-breathing fishes.

    Science.gov (United States)

    Randall, David J; Ip, Yuen K

    2006-11-01

    Ammonia is produced in the liver and excreted as NH(3) by diffusion across the gills. Elevated ammonia results in an increase in gill ventilation, perhaps via stimulation of gill oxygen chemo-receptors. Acidification of the water around the fish by carbon dioxide and acid excretion enhances ammonia excretion and constitutes "environmental ammonia detoxification". Fish have difficulties in excreting ammonia in alkaline water or high concentrations of environmental ammonia, or when out of water. The mudskipper, Periphthalmodon schlosseri, is capable of active NH(4)(+) transport, maintaining low internal levels of ammonia. To prevent a back flux of NH(3), these air-breathing fish can increase gill acid excretion and reduce the membrane NH(3) permeability by modifying the phospholipid and cholesterol compositions of their skin. Several air-breathing fish species can excrete ammonia into air through NH(3) volatilization. Some fish detoxify ammonia to glutamine or urea. The brains of some fish can tolerate much higher levels of ammonia than other animals. Studies of these fish may offer insights into the nature of ammonia toxicity in general.

  13. In vivo urea cycle flux distinguishes and correlates with phenotypic severity in disorders of the urea cycle

    Science.gov (United States)

    Lee, Brendan; Yu, Hong; Jahoor, Farook; O'Brien, William; Beaudet, Arthur L.; Reeds, Peter

    2000-01-01

    Urea cycle disorders are a group of inborn errors of hepatic metabolism that result in often life-threatening hyperammonemia and hyperglutaminemia. Clinical and laboratory diagnosis of partial deficiencies during asymptomatic periods is difficult, and correlation of phenotypic severity with either genotype and/or in vitro enzyme activity is often imprecise. We hypothesized that stable isotopically determined in vivo rates of total body urea synthesis and urea cycle-specific nitrogen flux would correlate with both phenotypic severity and carrier status in patients with a variety of different enzymatic deficiencies of the urea cycle. We studied control subjects, patients, and their relatives with different enzymatic deficiencies affecting the urea cycle while consuming a low protein diet. On a separate occasion the subjects either received a higher protein intake or were treated with an alternative route medication sodium phenylacetate/benzoate (Ucephan), or oral arginine supplementation. Total urea synthesis from all nitrogen sources was determined from [18O]urea labeling, and the utilization of peripheral nitrogen was estimated from the relative isotopic enrichments of [15N]urea and [15N]glutamine during i.v. co-infusions of [5-(amide)15N]glutamine and [18O]urea. The ratio of the isotopic enrichments of 15N-urea/15N-glutamine distinguished normal control subjects (ratio = 0.42 ± 0.06) from urea cycle patients with late (0.17 ± 0.03) and neonatal (0.003 ± 0.007) presentations irrespective of enzymatic deficiency. This index of urea cycle activity also distinguished asymptomatic heterozygous carriers of argininosuccinate synthetase deficiency (0.22 ± 0.03), argininosuccinate lyase deficiency (0.35 ± 0.11), and partial ornithine transcarbamylase deficiency (0.26 ± 0.06) from normal controls. Administration of Ucephan lowered, and arginine increased, urea synthesis to the degree predicted from their respective rates of metabolism. The 15N-urea/15N-glutamine ratio

  14. Analysis of Exhaled Breath for Disease Detection

    Science.gov (United States)

    Amann, Anton; Miekisch, Wolfram; Schubert, Jochen; Buszewski, Bogusław; Ligor, Tomasz; Jezierski, Tadeusz; Pleil, Joachim; Risby, Terence

    2014-06-01

    Breath analysis is a young field of research with great clinical potential. As a result of this interest, researchers have developed new analytical techniques that permit real-time analysis of exhaled breath with breath-to-breath resolution in addition to the conventional central laboratory methods using gas chromatography-mass spectrometry. Breath tests are based on endogenously produced volatiles, metabolites of ingested precursors, metabolites produced by bacteria in the gut or the airways, or volatiles appearing after environmental exposure. The composition of exhaled breath may contain valuable information for patients presenting with asthma, renal and liver diseases, lung cancer, chronic obstructive pulmonary disease, inflammatory lung disease, or metabolic disorders. In addition, oxidative stress status may be monitored via volatile products of lipid peroxidation. Measurement of enzyme activity provides phenotypic information important in personalized medicine, whereas breath measurements provide insight into perturbations of the human exposome and can be interpreted as preclinical signals of adverse outcome pathways.

  15. Improved compatibility between polystyrene and poly(vinylidene fluoride) by the addition of urea

    International Nuclear Information System (INIS)

    Melad, O.; Teim, O.A.; Sobeh, E.

    2005-01-01

    The viscosity behavior of dilute urea solution of dimethylformamide (Dmf) of Polystyrene-Poly(vinylidene fluoride) has been studied at 25 degree C. The results show that the polymer mixtures are incompatible in DMF solution in the absence of urea. The influence of urea addition on the degree of compatibility of the polymer mixture has been studied in terms of the compatibility parameters (A6/M, kbm , A [77] ,a and /?) respectively

  16. Determing the fate of selected antibiotics during nitrogen recovery via urea-formaldehdye synthesis

    OpenAIRE

    Kashobwe, Lackson

    2016-01-01

    The work presented here focused on the determination of fate of four selected antibiot-ics: enrofloaxicin, oxytetracyline, sulfamethoxazole and tylosin during nitrogen recovery from source separated urine via urea formaldehyde synthesis. The experimental pH was at 2 and temperature at 25°C throughout the chemical reaction, preventing urea hydroly-sis. Five main chemical reactions: aqueous + antibiotics, Urine + formaldehyde + antibi-otics (UF synthesis experiment), urea-formaldehyde polymer +...

  17. Fractionation of hydrogen and oxygen isotopes between hydrated and free water molecules in aqueous urea solution

    International Nuclear Information System (INIS)

    Kakiuchi, M.; Matsuo, S.

    1985-01-01

    Ratios of D/H and 18 O/ 16 O in the vapor phase in equilibrium with aqueous urea solution with different urea molalities were measured at 15 and 25 0 C. Under the assumption that urea solutions consist of two species, i.e., the urea-water cluster and free water, the results are interpreted to give the average hydration number, i.e., the number of water molecules per urea molecule in the urea-water cluster. Good agreement was obtained for the hydration number estimated independently from hydrogen and oxygen isotopic fractions. On the basis of hydrogen isotopic data at 25 0 C, the average hydration number of urea in the cluster is 6.3 +/- 0.8 at 2.1 m and 2.75 +/- 0.08 at saturation (20.15 m). The corresponding average hydration numbers based on oxygen isotopic data were calculated to be 6.7 +/- 2.4 at 2.1 m and 2.75 +/- 0.25 at urea saturation. HD 16 O is enriched in the urea-water cluster and H 2 18 O is enriched in free water. Isotopic partitioning between the cluster and free water is markedly different from those between hydration spheres and free water in aqueous electrolyte solutions. 29 references, 6 figures, 5 tables

  18. The effect of urea on the corrosion behavior of different dental alloys.

    Science.gov (United States)

    Geckili, Onur; Bilhan, Hakan; Bilgin, Tayfun; Anthony von Fraunhofer, J

    2012-01-01

    Intraoral corrosion of dental alloys has biological, functional, and esthetic consequences. Since it is well known that the salivary urea concentrations undergo changes with various diseases, the present study was undertaken to determine the effect of salivary urea concentrations on the corrosion behavior of commonly used dental casting alloys. Three casting alloys were subjected to polarization scans in synthetic saliva with three different urea concentrations. Cyclic polarization clearly showed that urea levels above 20 mg/100 ml decreased corrosion current densities, increased the corrosion potentials and, at much higher urea levels, the breakdown potentials. The data indicate that elevated urea levels reduced the corrosion susceptibility of all alloys, possibly through adsorption of organics onto the metal surface. This study indicates that corrosion testing performed in sterile saline or synthetic saliva without organic components could be misleading.

  19. Comparison of an increased waist circumference with a positive hydrogen breath test as a clinical predictor of lactose intolerance.

    Science.gov (United States)

    Zapata-Castilleja, Carlos A; Montes-Tapia, Fernando F; Treviño-Garza, Consuelo; Martínez-Cobos, María C; García-Cantú, Jesús; Arenas-Fabbri, Vincenzo; de la O-Escamilla, Norma; de la O-Cavazos, Manuel

    2017-04-01

    Lactose intolerance is a common disease in pediatrics, and its wrong diagnosis will lead to morbidity. The primary objective of this study was to assess the usefulness of an increased waist circumference during the hydrogen breath test as a predictor of lactose intolerance. The secondary objective was to analyze the impact of body mass index, waist circumference measurement, and age on the abdominal distension of patients with lactose intolerance. A total of 138 subjects aged 3 to 15 years were included. They underwent serial measurements of the waist circumference and hydrogen levels in the breath every 30 minutes over 3 hours during the hydrogen breath test. Out of the entire sample, 35 (25.4%) patients had lactose intolerance. An increase of 0.85 cm in waist circumference compared to the baseline waist circumference results in a sensitivity of 88% and a specificity of 85% to predict lactose intolerance (odds ratio: 42.14, 95% confidence interval: 13.08-135.75, p ≤ 0.001). The body mass index and waist circumference measurement did not affect abdominal distension (p= not significant); however, age modified the time of distension. A 0.85 cm increase in waist circumference compared to the baseline waist circumference during the hydrogen breath test is a useful parameter for the diagnosis of lactose intolerance in pediatrics. Variations in relation to body mass index and waist circumference did not affect the usefulness of an increased waist circumference, unlike age.

  20. Effect of urea treatment on digestibility and utilization of sorghum straw

    Directory of Open Access Journals (Sweden)

    Nianogo A.J.

    1999-01-01

    Full Text Available Nine male goats and nine castrated lambs were randomly divided into three groups of six animals to receive one of three experimental diets in a digestion trial. Diet S, provided chopped sorghum straw (SS, 28/ concentrate (C and 10/ Dolichos lablab hay (D. Diet Su1 provided SS containing 2/ urea, 24/ C and 12/ D, and diet Sue1 provided SS treated to contain 2/ urea and ensiled for 28 days, plus 25/ C and 14/ D. Twenty four lambs were randomly divided into three groups of eight animals to receive one of three diets in a 56-day growth trial; diet S2 provided SS plus 60/ C; diet Su2 provided SS containing 2/ urea plus 60/ C, and diet Sue2 provided SS treated to contain 2/ urea and ensiled for 28 days, plus 60/ C. The digestion trial showed higher (P<.05 daily intake of dry matter, organic matter, crude protein and neutral detergent fiber for S, than for Sue1 and Su1. Dry matter intake was 55.93; 39.42 and 42.34 g[kgE0.75E-1 for S1, Su1 and Sue1, respectively. Dry matter intake was slightly higher for lambs [50 g[kgE0.75E-1] than for goats [42 g[kE0.75E-1]. There was no effect of dietary treatments on apparent nutrient digestibility. During the growth trial, intake of straw varied from 17.97 (S2 to 24.78 g[kgE0.75E-1 (Sue2, but differences were not significant. Daily gain did not differ between treatments. Total feed intake and feed efficiency were only slightly affected by dietary treatments. Average feed intake was 4.36/ of body weight. High concentrate intakes may have upset the effect of urea treatment and silo fermentation in this study.

  1. Rhodium catalyzed regioselective arene homologation of aryl urea via double C-H bond activation and migratory insertion of alkyne

    Institute of Scientific and Technical Information of China (English)

    Yan Wang; Hao Zhou; Ke Xu; Mei-Hua Shen; Hua-Dong Xu

    2017-01-01

    A convenient rhodium catalyzed oxidative arene homologation of aniline derivatives with symmetrical or unsymmetrical alkynes using Cu(OAc)2 as oxidant is described.Urea group is shown to be effective as a directing group for initial ortho C-H activation.Two migratory insertion events of alkyne into Rh-C bond occur successively,both with complete regioselectivity.This method is particularly useful for synthesis of polyarenes with different substituents,which has not been reported with conventional protocol.A mechanism has been proposed to explain the observed data.

  2. Tidal volume single breath washout of two tracer gases--a practical and promising lung function test.

    Directory of Open Access Journals (Sweden)

    Florian Singer

    Full Text Available BACKGROUND: Small airway disease frequently occurs in chronic lung diseases and may cause ventilation inhomogeneity (VI, which can be assessed by washout tests of inert tracer gas. Using two tracer gases with unequal molar mass (MM and diffusivity increases specificity for VI in different lung zones. Currently washout tests are underutilised due to the time and effort required for measurements. The aim of this study was to develop and validate a simple technique for a new tidal single breath washout test (SBW of sulfur hexafluoride (SF(6 and helium (He using an ultrasonic flowmeter (USFM. METHODS: The tracer gas mixture contained 5% SF(6 and 26.3% He, had similar total MM as air, and was applied for a single tidal breath in 13 healthy adults. The USFM measured MM, which was then plotted against expired volume. USFM and mass spectrometer signals were compared in six subjects performing three SBW. Repeatability and reproducibility of SBW, i.e., area under the MM curve (AUC, were determined in seven subjects performing three SBW 24 hours apart. RESULTS: USFM reliably measured MM during all SBW tests (n = 60. MM from USFM reflected SF(6 and He washout patterns measured by mass spectrometer. USFM signals were highly associated with mass spectrometer signals, e.g., for MM, linear regression r-squared was 0.98. Intra-subject coefficient of variation of AUC was 6.8%, and coefficient of repeatability was 11.8%. CONCLUSION: The USFM accurately measured relative changes in SF(6 and He washout. SBW tests were repeatable and reproducible in healthy adults. We have developed a fast, reliable, and straightforward USFM based SBW method, which provides valid information on SF(6 and He washout patterns during tidal breathing.

  3. Tidal Volume Single Breath Washout of Two Tracer Gases - A Practical and Promising Lung Function Test

    Science.gov (United States)

    Singer, Florian; Stern, Georgette; Thamrin, Cindy; Fuchs, Oliver; Riedel, Thomas; Gustafsson, Per; Frey, Urs; Latzin, Philipp

    2011-01-01

    Background Small airway disease frequently occurs in chronic lung diseases and may cause ventilation inhomogeneity (VI), which can be assessed by washout tests of inert tracer gas. Using two tracer gases with unequal molar mass (MM) and diffusivity increases specificity for VI in different lung zones. Currently washout tests are underutilised due to the time and effort required for measurements. The aim of this study was to develop and validate a simple technique for a new tidal single breath washout test (SBW) of sulfur hexafluoride (SF6) and helium (He) using an ultrasonic flowmeter (USFM). Methods The tracer gas mixture contained 5% SF6 and 26.3% He, had similar total MM as air, and was applied for a single tidal breath in 13 healthy adults. The USFM measured MM, which was then plotted against expired volume. USFM and mass spectrometer signals were compared in six subjects performing three SBW. Repeatability and reproducibility of SBW, i.e., area under the MM curve (AUC), were determined in seven subjects performing three SBW 24 hours apart. Results USFM reliably measured MM during all SBW tests (n = 60). MM from USFM reflected SF6 and He washout patterns measured by mass spectrometer. USFM signals were highly associated with mass spectrometer signals, e.g., for MM, linear regression r-squared was 0.98. Intra-subject coefficient of variation of AUC was 6.8%, and coefficient of repeatability was 11.8%. Conclusion The USFM accurately measured relative changes in SF6 and He washout. SBW tests were repeatable and reproducible in healthy adults. We have developed a fast, reliable, and straightforward USFM based SBW method, which provides valid information on SF6 and He washout patterns during tidal breathing. PMID:21423739

  4. Tidal volume single breath washout of two tracer gases--a practical and promising lung function test.

    Science.gov (United States)

    Singer, Florian; Stern, Georgette; Thamrin, Cindy; Fuchs, Oliver; Riedel, Thomas; Gustafsson, Per; Frey, Urs; Latzin, Philipp

    2011-03-10

    Small airway disease frequently occurs in chronic lung diseases and may cause ventilation inhomogeneity (VI), which can be assessed by washout tests of inert tracer gas. Using two tracer gases with unequal molar mass (MM) and diffusivity increases specificity for VI in different lung zones. Currently washout tests are underutilised due to the time and effort required for measurements. The aim of this study was to develop and validate a simple technique for a new tidal single breath washout test (SBW) of sulfur hexafluoride (SF(6)) and helium (He) using an ultrasonic flowmeter (USFM). The tracer gas mixture contained 5% SF(6) and 26.3% He, had similar total MM as air, and was applied for a single tidal breath in 13 healthy adults. The USFM measured MM, which was then plotted against expired volume. USFM and mass spectrometer signals were compared in six subjects performing three SBW. Repeatability and reproducibility of SBW, i.e., area under the MM curve (AUC), were determined in seven subjects performing three SBW 24 hours apart. USFM reliably measured MM during all SBW tests (n = 60). MM from USFM reflected SF(6) and He washout patterns measured by mass spectrometer. USFM signals were highly associated with mass spectrometer signals, e.g., for MM, linear regression r-squared was 0.98. Intra-subject coefficient of variation of AUC was 6.8%, and coefficient of repeatability was 11.8%. The USFM accurately measured relative changes in SF(6) and He washout. SBW tests were repeatable and reproducible in healthy adults. We have developed a fast, reliable, and straightforward USFM based SBW method, which provides valid information on SF(6) and He washout patterns during tidal breathing.

  5. Effects of exogenous lactase administration on hydrogen breath excretion and intestinal symptoms in patients presenting lactose malabsorption and intolerance.

    Science.gov (United States)

    Ibba, Ivan; Gilli, Agnese; Boi, Maria Francesca; Usai, Paolo

    2014-01-01

    To establish whether supplementation with a standard oral dose of Beta-Galactosidase affects hydrogen breath excretion in patients presenting with lactose malabsorption. Ninety-six consecutive patients positive to H2 Lactose Breath Test were enrolled. Mean peak H2 levels, the time to reach the peak H2, the time to reach the cut-off value of 20 ppm, the cumulative breath H2 excretion, the areas under the curve, and a Visual Analogical 10-point Scale for symptoms were calculated. Genotyping of the C/T-13910 variant was carried out. Following the oral administration of Beta-Galactosidase, in 21.88% of the cases, H2 Lactose Breath Test became negative (Group A), while mean peak H2 levels (74.95 ppm versus 7.85), P lactose malabsorption presents a significant variability.

  6. Gastric emptying and related symptoms in patients treated with buspirone, amitriptyline or clebopride: a "real world" study by 13C-octanoic Acid Breath Test.

    Science.gov (United States)

    Caviglia, Gian P; Sguazzini, Carlo; Cisarò, Fabio; Ribaldone, Davide G; Rosso, Chiara; Fagoonee, Sharmila; Smedile, Antonina; Saracco, Giorgio M; Astegiano, Marco; Pellicano, Rinaldo

    2017-12-01

    Gastric motility is a key-factor in the pathogenesis of functional dyspepsia (FD). 13C-octanoic Acid Breath Test (OBT) is a tool used for measuring gastric emptying time in clinical setting. We aimed to investigate the variation in FD symptoms and OBT parameters after treatment with buspirone, amitriptyline or clebopride. Between Jan-2007 and Dec-2014, we enrolled 59 patients with FD unresponsive to first-line therapy with proton pump inhibitors and/or domperidone that underwent OBT before and after 3 months of buspirone (N.=32), amitriptyline (N.=16) or clebopride (N.=11) treatment. Early satiation severity was positively correlated with gastric half emptying time (t1/2) (r=0.3789, P=0.003) and gastric lag phase (r=0.3371, P=0.011), and negatively correlated with gastric emptying coefficient (r=-0.3231, P=0.015). A reduction in t1/2 measurement in association to postprandial fullness, and early satiation severity improvement was observed (P=0.009, P=0.005 and Pclebopride. Patients with FD, non-responders to first-line therapy and reporting meal-related discomfort, may benefit from buspirone or amitriptyline-based therapies.

  7. Synthesis and Characterization of Low Solubility Poly Carbonyl Urea as a Slow Release Fertilizer

    International Nuclear Information System (INIS)

    Liu, Y.; Sun, X.

    2016-01-01

    Low solubility poly carbonyl urea has been successfully synthesized by the reaction of urea with methyl carbamate (MC) under the conditions of potassium carbonate as an initiator. It was characterized by FT-IR, /sup 13/C-NMR, and elemental analyser. In addition, the influences of the quantity of initiator, reaction temperature, reaction time and the molar ratio of starting materials on the conversion are discussed in detail. All those observations suggest that when initiator as 10 wt percent of urea, the reaction temperature 160 Degree C, 6 h, and n(urea):n(MC)=1:10, the reaction conversion rate can reach 78.4 percent. Moreover, the novel procedure is reported for the first time and has a significant N slow release properties, the N release in soil was 80 percent over 30 days. (author)

  8. A comparison between lactose breath test and quick test on duodenal biopsies for diagnosing lactase deficiency in patients with self-reported lactose intolerance.

    Science.gov (United States)

    Furnari, Manuele; Bonfanti, Daria; Parodi, Andrea; Franzè, Jolanda; Savarino, Edoardo; Bruzzone, Luca; Moscatelli, Alessandro; Di Mario, Francesco; Dulbecco, Pietro; Savarino, Vincenzo

    2013-02-01

    A lactose breath test (LBT) is usually used to diagnose lactase deficiency, and a lactose quick test (LQT) has been proposed as a new test on duodenal biopsies to detect this disorder. We aimed to assess the diagnostic accuracy of LBT and LQT and their ability to predict the clinical response to a lactose-free diet in patients with self-reported lactose intolerance. Fifty-five patients (age 47 ± 14 y; M/F 15/36) underwent upper gastrointestinal endoscopy and 25g-LBT. Two duodenal biopsies were taken to determine lactase deficiency (normal, mild, or severe) by LQT and to rule out other causes of secondary lactose malabsorption. Patients with a positive LBT and normal LQT also underwent a glucose breath test to exclude small intestinal bacterial overgrowth as a cause of the former result. The severity of gastrointestinal symptoms was measured with a GSS questionnaire, under basal condition and 1 month after a lactose-free diet. Lactose malabsorption was detected in 31/51 patients with LBT and in 37/51 patients with LQT (P = NS). Celiac disease was found in 2 patients. Two LBT+ patients showed a positive glucose breath test for small intestinal bacterial overgrowth. Eight patients had a mild hypolactasia by LQT and a negative LBT, but they had a significant improvement of symptoms after diet. LQT and LBT were concordant in 83% of cases and predicted the response to a lactose-free diet in 98% and 81% of the cases, respectively (P = 0.03). LQT is as sensitive as LBT in detecting lactase deficiency; however, it seems to be more accurate than LBT in predicting the clinical response to a lactose-free diet.

  9. Radiosynthesis and ex vivo evaluation of [11C-carbonyl]carbamate- and urea-based monoacylglycerol lipase inhibitors

    International Nuclear Information System (INIS)

    Hicks, Justin W.; Parkes, Jun; Tong, Junchao; Houle, Sylvain; Vasdev, Neil; Wilson, Alan A.

    2014-01-01

    Introduction: Monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH) are the two primary enzymes that regulate the tone of endocannabinoid signaling. Although new PET radiotracers have been discovered for imaging FAAH in vivo, no such radiotracer exists for imaging MAGL. Here we report the radiosynthesis of five candidate MAGL radiotracers and their ex vivo evaluations in mice and rats. Methods: Candidate carbamate and urea MAGL inhibitors were radiolabeled at the carbonyl position by [ 11 C]CO 2 fixation. Radiotracers were administered (tail-vein injection) to rodents and brain uptake of radioactivity measured at early and late time points ex vivo. Specificity of uptake was explored by pretreatment with unlabeled inhibitors (2 mg/kg, ip) 30 min prior to radiotracer administration. Results: All five candidate MAGL radiotracers were prepared in high specific activity (> 65 GBq/μmol) and radiochemical purity (> 98%). Moderate brain uptake (0.2–0.8 SUV) was observed for each candidate while pretreatment did not reduce uptake for four of the five tested. For two candidates ([ 11 C]12 and [ 11 C]14), high retention of radioactivity was observed in the blood (ca. 10 and 4 SUV at 40 min) which was blocked by pretreatment with unlabeled inhibitors. The most promising candidate, [ 11 C]18, demonstrated moderate brain uptake (ca. 0.8 SUV) which showed circa 50% blockade by pretreatment with unlabeled 18. Conclusion: One putative and four reported potent and selective MAGL inhibitors have been radiolabeled via [ 11 C]CO 2 fixation as radiotracers for this enzyme. Despite the promising in vitro pharmacological profile, none of the five candidate radiotracers exhibited in vivo behavior suitable for PET neuroimaging

  10. Neurological implications of urea cycle disorders

    Science.gov (United States)

    Summar, M.; Leonard, J. V.

    2013-01-01

    Summary The urea cycle disorders constitute a group of rare congenital disorders caused by a deficiency of the enzymes or transport proteins required to remove ammonia from the body. Via a series of biochemical steps, nitrogen, the waste product of protein metabolism, is removed from the blood and converted into urea. A consequence of these disorders is hyperammonaemia, resulting in central nervous system dysfunction with mental status changes, brain oedema, seizures, coma, and potentially death. Both acute and chronic hyperammonaemia result in alterations of neurotransmitter systems. In acute hyperammonaemia, activation of the NMDA receptor leads to excitotoxic cell death, changes in energy metabolism and alterations in protein expression of the astrocyte that affect volume regulation and contribute to oedema. Neuropathological evaluation demonstrates alterations in the astrocyte morphology. Imaging studies, in particular 1H MRS, can reveal markers of impaired metabolism such as elevations of glutamine and reduction of myoinositol. In contrast, chronic hyperammonaemia leads to adaptive responses in the NMDA receptor and impairments in the glutamate–nitric oxide–cGMP pathway, leading to alterations in cognition and learning. Therapy of acute hyperammonaemia has relied on ammonia-lowering agents but in recent years there has been considerable interest in neuroprotective strategies. Recent studies have suggested restoration of learning abilities by pharmacological manipulation of brain cGMP with phosphodiesterase inhibitors. Thus, both strategies are intriguing areas for potential investigation in human urea cycle disorders. PMID:18038189

  11. Utilization of dietary urea in rainbow trout.

    Science.gov (United States)

    Kaushik, S J; Dabrowski, K R; Dabrowska, H; Olah, E; Luquet, P

    1983-01-01

    Experiments were conducted to examine the potential utilization of dietary urea by rainbow trout. A control diet and two diets supplemented with 1 and 3% of urea were fed to fish. Postprandial levels of urea and ammonia in blood plasma, and postprandial excretion of these metabolites were followed during 24 h. Apparent digestibility of urea in rainbow trout was very high (greater than 98%). Maximum values of urea levels in plasma were reached 6 h (32.3 +/- 10.2 micrograms/ml) after a meal in the control fish and respectively 6 h (83.4 +/- 18.4 micrograms/ml) and 8 h (250.3 +/- 96.1 micrograms/ml) after a meal in trout fed 1 and 3% urea diets. Peaks of urea excretion rates appeared 7-9 h after meal, coinciding with the highest circulating urea concentration. Total daily urea excretion amounted to 5.53, 10.43 and 33.80 mg urea N/100 mg N intake in trout fed the control, 1 and 3% urea diets, respectively. It is concluded that the dietary urea is readily absorbed in the digestive tract of trout but is totally excreted thus leading to no beneficial effect on nitrogen balance. This excretion of urea also takes place passively without any increase in energy demands.

  12. Measurement of urea kinetics in vivo by means of a constant tracer infusion of di-15N-urea

    International Nuclear Information System (INIS)

    Wolfe, R.R.

    1981-01-01

    We have assessed the feasibility of studying urea metabolism in vivo in both steady state and nonsteady state situations by means of the primed constant infusion of di-15N-urea and the analysis of the resulting enrichment in plasma urea. Both hepatectomized dogs with known rates of urea infusion and intact dogs were studied. The enrichment of the bistrimethylsilyl derivative of urea was determined on a gas chromatograph-mass spectrometer. Selected ion monitoring was set for m/e 189 (M - 15), m/e 190 (A + 1), and m/e 191 (A + 2), thus enabling the calculation of the rate of urea production from nonrecycled NH3 (from A + 2 data) (Ra N), the rate of recycling of NH3 into urea (Ra R) (from A + 1 data), and thus the total rate of urea production (Ra N + Ra R). When urine collections were made, the incorporation of urea-N into protein was estimated from the difference between Ra N and urea excretion. We found that, in the steady state in a hepatectomized dog, the rate of appearance of urea can be determined accurately. In the nonsteady state in both hepatectomized and intact dogs, urea appearance could be estimated within +/- 20% in most situations. The only situation in which this was not the case was when we attempted to measure rapid changes in Ra R. Thus, within limits, this can be a useful technique enabling the quantitation of various aspects of urea metabolism

  13. The assessment of the breath hold and the free breath methods about the blood flow evaluation by using phase contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Ho [Dept. of Radiology, Konkuk Medical center, Seoul (Korea, Republic of)

    2016-06-15

    Measurement of cardiac blood flow using the magnetic resonance imaging has been limited due to breathing and involuntary movements of the heart. The present study attempted to improve the accuracy of cardiac blood flow testing through phase contrast magnetic resonance imaging by presenting the adequate breathing method and imaging variables by comparing the measurement values of cardiac blood flow. Each was evaluated by comparing the breath hold retrospective 1NEX and non breath hold retrospective 1-3NEX in the ascending aorta and descending aorta. As a result, the average blood flow amount/ velocity of the breath hold retrosepctive 1NEX method in the ascending aorta were 96.17±19.12 ml/sec, 17.04±4.12 cm/sec respectively, which demonstrates a statistically significant difference(p<0.05) with the non-breath hold retrospective method 1NEX of 72.31±13.27 ml and 12.32±3.85. On the other hand, the average 2NEX blood flow and mean flow velocity is 101.90±24.09, 16.84±4.32, 3NEX 103.06±25.49, 16.88±4.19 did not show statistically significant differences(p>0.05).The average blood flow amount/ velocity of the breath hold retrospective 1NEX method in the descending aorta were 76.68±19.72 ml/s, and 22.23±4.8, which did not demonstrate a significant difference in comparison to non-breath hold retrospective method 1-3 NEX. Therefore, the non breath hold retrospective method does not significantly differ in terms of cardiac blood flow in comparison with the breath hold retrospective method in accordance with the increase of NEX, so pediatric patients or patients who are not able to breathe well must have the diagnostic value of their cardiac blood flow tests improved.

  14. Potentiometric urea biosensor based on an immobilised fullerene-urease bio-conjugate.

    Science.gov (United States)

    Saeedfar, Kasra; Heng, Lee Yook; Ling, Tan Ling; Rezayi, Majid

    2013-12-06

    A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease) bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate) (PnBA) membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10-3 M to 8.28 × 10-5 M. The biosensor's sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor's response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days.

  15. Effect of nitrogen supplementation on urea kinetics and microbial use of recycled urea in steers consuming corn-based diets.

    Science.gov (United States)

    Brake, D W; Titgemeyer, E C; Jones, M L; Anderson, D E

    2010-08-01

    We studied the effects of supplementing N as distillers dried grains with solubles (DDGS) or urea to steers consuming corn-based diets. Six ruminally and duodenally cannulated steers (244 kg) were used in 2 concurrent 3 x 3 Latin squares and fed 1 of 3 corn-based diets: control (10.2% CP), urea (13.3% CP), or DDGS (14.9% CP). Periods were 14 d, with 9 d for adaptation and 5 d for collection of urine and feces. Urinary (15)N(15)N-urea enrichments, resulting from venous infusions of (15)N(15)N-urea, were used to measure urea kinetics. Dry matter intake (6.0 kg/d) was not affected by treatment, but N intake differed (99, 151, and 123 g/d for the control, DDGS, and urea treatments, respectively). Urea-N synthesis tended to be greater (P = 0.09) for DDGS (118 g/d) than for the control treatment (52 g/d), with the urea treatment (86 g/d) being intermediate. Urea-N excreted in the urine was greater (P urea treatments (29 g/d) than for the control treatment (13 g/d). Gastrointestinal entry of urea-N was not statistically different among treatments (P = 0.25), but was numerically greatest for DDGS (83 g/d), intermediate for urea (57 g/d), and least for the control (39 g/d). The amount of urea-N returned to the ornithine cycle tended to be greater (P = 0.09) for the DDGS treatment (47 g/d) than for the urea (27 g/d) or control treatment (16 g/d). The fraction of recycled urea-N that was apparently used for anabolism tended (P = 0.14) to be greater for the control treatment (0.56) than for the DDGS treatment (0.31), with the urea treatment (0.45) being intermediate, but no differences were observed among treatments in the amount of urea-N used for anabolism (P = 0.66). Urea kinetics in cattle fed grain-based diets were largely related to the amount of N consumed. The percentage of urea production that was captured by ruminal bacteria was greater (P urea treatment (22%), but the percentage of duodenal microbial N flow that was derived from recycled urea-N tended (P = 0.10) to

  16. Breath hydrogen analysis in patients with ileoanal pouch anastomosis

    DEFF Research Database (Denmark)

    Bruun, E; Meyer, J N; Rumessen, J J

    1995-01-01

    The possible influence on functional outcomes of hydrogen production in the ileoanal pouch after restorative proctocolectomy was investigated by means of lactulose H2 breath tests. Eight of 15 patients had significant increases in breath hydrogen after 10 g lactulose. One patient declined...... to participate in further investigations, the remaining seven responders had no evidence of small bowel bacterial overgrowth after glucose H2 breath tests. The ability to produce hydrogen by anaerobic fermentation of lactulose in the pouch was unrelated to the age of the patients or of the pouch. Seven of eight...... responders had successive breath tests after ingestion of lactulose 20 g and wheat starch 100 g. Five of seven had significant increases after lactulose but none after wheat starch. The overall function of the pouch continence, spontaneity of defecation, and 24 hour stool frequency was significantly better...

  17. The permeability of red blood cells to chloride, urea and water

    DEFF Research Database (Denmark)

    Brahm, Jesper

    2013-01-01

    This study extends permeability (P) data on chloride, urea and water in red blood cells (RBC), and concludes that the urea transporter (UT-B) does not transport water. P of chick, duck, Amphiuma means, dog and human RBC to (36)Cl(-), (14)C-urea and (3)H2O was determined under self....... Temperature dependence, as measured by apparent activation energy, EA, of PCl is 117.8 (duck), 74.9 (Amphiuma) and 89.6 kJ mol(-1) (dog). The EA of Purea is 69.6 (duck) and 53.3 kJ mol(-1) (Amphiuma), and that of Pd is 34.9 (duck) and 32.1 kJ mol(-1) (Amphiuma). The present and previous RBC studies indicate......-exchange conditions. At 25°C and pH 7.2-7.5, PCl is 0.94×10(-4)-2.15×10(-4) cm s(-1) for all RBC species at [Cl]=127-150 mmol l(-1). In chick and duck RBC, Purea is 0.84×10(-6) and 1.65×10(-6) cm s(-1), respectively, at [urea]=1-500 mmol l(-1). In Amphiuma, dog and human RBC, Purea is concentration dependent (1...

  18. Determination of breath acetone in 149 type 2 diabetic patients using a ringdown breath-acetone analyzer.

    Science.gov (United States)

    Sun, Meixiu; Chen, Zhuying; Gong, Zhiyong; Zhao, Xiaomeng; Jiang, Chenyu; Yuan, Yuan; Wang, Zhennang; Li, Yingxin; Wang, Chuji

    2015-02-01

    Over 90% of diabetic patients have Type 2 diabetes. Although an elevated mean breath acetone concentration has been found to exist in Type 1 diabetes (T1D), information on breath acetone in Type 2 diabetes (T2D) has yet to be obtained. In this study, we first used gas chromatography-mass spectrometry (GC-MS) to validate a ringdown breath-acetone analyzer based on the cavity-ringdown-spectroscopy technique, through comparing breath acetone concentrations in the range 0.5-2.5 ppm measured using both methods. The linear fitting of R = 0.99 suggests that the acetone concentrations obtained using both methods are consistent with a largest standard deviation of ±0.4 ppm in the lowest concentration of the range. Next, 620 breath samples from 149 T2D patients and 42 healthy subjects were collected and tested using the breath analyzer. Four breath samples were taken from each subject under each of four different conditions: fasting, 2 h post-breakfast, 2 h post-lunch, and 2 h post-dinner. Simultaneous blood glucose levels were also measured using a standard diabetic-management blood-glucose meter. For the 149 T2D subjects, their exhaled breath acetone concentrations ranged from 0.1 to 19.8 ppm; four different ranges of breath acetone concentration, 0.1-19.8, 0.1-7.1, 0.1-6.3, and 0.1-9.5 ppm, were obtained for the subjects under the four different conditions, respectively. For the 42 healthy subjects, their breath acetone concentration ranged from 0.1 to 2.6 ppm; four different ranges of breath acetone concentration, 0.3-2.6, 0.1-2.6, 0.1-1.7, and 0.3-1.6 ppm, were obtained for the four different conditions. The mean breath acetone concentration of the 149 T2D subjects was determined to be 1.5 ± 1.5 ppm, which was 1.5 times that of 1.0 ± 0.6 ppm for the 42 healthy subjects. No correlation was found between the breath acetone concentration and the blood glucose level of the T2D subjects and the healthy volunteers. This study using a relatively large number of

  19. RENAL FUNCTION TEST ON THE BASIS OF SERUM CREATININE AND UREA IN TYPE-2 DIABETICS AND NONDIABETICS

    Directory of Open Access Journals (Sweden)

    P. Singh

    2014-01-01

    Full Text Available Background: Type-2 diabetes mellitus has quickly become a global health problem due to rapidly increasing population growth, aging, urbanization and increasing prevalence of obesity and physical inactivity. Diabetic nephropathy is one of the major causes of chronic renal failure. Both serum urea and creatinine are widely used to assess the function of kidney. This study was conducted to observe the impaired renal function in type 2 diabetics and compare with non-diabetics controls. Method: To determine the incidence of renal dysfunction in diabetics in Nepalgunj medical college and Hospital , Nepalgunj , Banke, Nepal , blood samples from 100 diabetic subjects and 100 non-diabetic controls were taken between the period 1st February  , 2012  to  31st January , 2013 for investigation of  plasma glucose fasting(FPG, blood urea and serum creatinine. These biochemical parameters were determined by using a fully automated clinical chemistry analyzer. Results: Our findings showed that the level of blood urea (P<0.0001, 95%Cl and serum creatinine (P≈0.0004,95%Cl were significantly higher in type 2 diabetics as compared to non-diabetics in both male and female. There was no significant difference between diabetic male and female. 15 out of 100 diabetes samples have high urea level whereas 7 out of 100 had increased creatinine level. In control only 3 samples had high urea value and 1 had high creatinine level. There was statistical significant increased in urea level with increased in blood sugar level. Conclusion: Blood urea and creatinine is widely accepted to assess the renal functions. Good control of blood glucose level is absolute requirement to prevent progressive renal impairment.

  20. Dispersion Interactions between Urea and Nucleobases Contribute to the Destabilization of RNA by Urea in Aqueous Solution

    Science.gov (United States)

    Kasavajhala, Koushik; Bikkina, Swetha; Patil, Indrajit; MacKerell, Alexander D.; Priyakumar, U. Deva

    2015-01-01

    Urea has long been used to investigate protein folding and, more recently, RNA folding. Studies have proposed that urea denatures RNA by participating in stacking interactions and hydrogen bonds with nucleic acid bases. In this study, the ability of urea to form unconventional stacking interactions with RNA bases is investigated using ab initio calculations (RI-MP2 and CCSD(T) methods with the aug-cc-pVDZ basis set). A total of 29 stable nucleobase-urea stacked complexes are identified in which the intermolecular interaction energies (up to −14 kcal/mol) are dominated by dispersion effects. Natural bond orbital (NBO) and atoms in molecules (AIM) calculations further confirm strong interactions between urea and nucleobases. Calculations on model systems with multiple urea and water molecules interacting with a guanine base lead to a hypothesis that urea molecules along with water are able to form cage-like structures capable of trapping nucleic acid bases in extrahelical states by forming both hydrogen bonded and dispersion interactions, thereby contributing to the unfolding of RNA in the presence of urea in aqueous solution. PMID:25668757

  1. Imaging and retention measurements of selenium 75 homocholic acid conjugated with taurine, and the carbon 14 glycochol breath test to document ileal dysfunction due to late radiation damage

    International Nuclear Information System (INIS)

    Valdes Olmos, R.; Hartog Jager, F. den; Hoefnagel, C.; Taal, B.; Netherlands Cancer Inst., Amsterdam

    1991-01-01

    In order to assess ileal dysfunction in patients with complaints after pelvic radiation therapy, retention measurements and scintigraphic imaging with selenium 75 homocholic acid conjugated with taurine ( 75 Se-HCAT), combined with the carbon 14 clycochol breath test, were evaluated in 39 patients. In 22 patients without ileal resection the results of the 75 Se-HCAT test and the breath test differentiated between a normal functioning ileum (both tests negative) and ileal dysfunction as a cause of complaints (one or both tests positive). Among the patients with ileal dysfunction, the combination of both tests permitted those with bacterial overgrowth (breath test positive, 75 Se-HCAT negative) to be separated from patients with evidence of bile acid malabsorption ( 75 Se-HCAT positive, breath test positive or negative). In 17 patients with small-bowel resection, the 75 Se-HCAT test helped to estimate the severity of bile acid malabsorption with implications for therapy. In this group the breath test was false-negative in 7 cases with abnormal 75 Se-HCAT. Additional systematically performed scintigraphic imaging improved the accuracy of the 75 Se-HCAT test, revealing cases with prolonged colonic accumulation of the radiopharmaceutical, causing spurious retention values. In conclusion, assessment of ileal dysfunction by nuclear medicine techniques in post-irradiation conditions provides information about the aetiology and therefore the possibility of adjustment in the clinical management. (orig.)

  2. Afternoon serum-melatonin in sleep disordered breathing.

    Science.gov (United States)

    Ulfberg, J; Micic, S; Strøm, J

    1998-08-01

    To study afternoon serum-melatonin values in patients with sleep disordered breathing. Melatonin has a strong circadian rhythm with high values during the night-time and low values in the afternoon. Sleep disordered breathing may change the circadian rhythm of melatonin which may have diagnostic implications. The Sleep Laboratory, The Department of Internal Medicine, Avesta Hospital, Sweden, and the Department of Anaesthesiology, Glostrup University Hospital, Copenhagen, Denmark. We examined 60 consecutive patients admitted for sleep disordered breathing and 10 healthy non snoring controls. The patients underwent a sleep apnoea screening test having a specificity of 100% for the obstructive sleep apnoea syndrome (OSAS) using a combination of static charge sensitive bed and oximetry. Obstructive sleep apnoea syndrome was found in 49 patients, eight patients had borderline sleep disordered breathing (BSDB) and three patients were excluded due to interfering disease. Patients and controls had an afternoon determination of serum-melatonin. The Epworth Sleepiness Scale was used to score day-time sleepiness. In comparison with normal controls patients suffering from OSAS had significantly higher serum-melatonin levels in the afternoon. However, as a diagnostic test for OSAS in patients with sleep disordered breathing serum-melatonin showed a low sensitivity but a high specificity. The results indicate that breathing disorders during sleep in general affect pineal function. Sleep disordered breathing seems to disturb pineal function. Determination of afternoon serum-melatonin alone or together with a scoring of daytime sleepiness does not identify OSAS-patients in a heterogeneous population of patients complaining of heavy snoring and excessive daytime sleepiness.

  3. Exercise training improves breathing strategy and performance during the six-minute walk test in obese adolescents.

    Science.gov (United States)

    Mendelson, Monique; Michallet, Anne-Sophie; Perrin, Claudine; Levy, Patrick; Wuyam, Bernard; Flore, Patrice

    2014-08-15

    We aimed to examine ventilatory responses during the six-minute walk test in healthy-weight and obese adolescents before and after exercise training. Twenty obese adolescents (OB) (age: 14.5±1.7 years; BMI: 34.0±4.7kg·m(-2)) and 20 age and gender-matched healthy-weight adolescents (HW) (age: 15.5±1.5 years; BMI: 19.9±1.4kg·m(-2)) completed six-minute walk test during which breath-by-breath gas analysis and expiratory flow limitation (expFL) were measured. OB participated in a 12-week exercise-training program. Comparison between HW and OB participants showed lower distance achieved during the 6MWT in OB (-111.0m, 95%CI: -160.1 to 62.0, p<0.05) and exertional breathlessness was greater (+0.78 a.u., 95%CI: 0.091-3.27, p=0.039) when compared with HW. Obese adolescents breathed at lower lung volumes, as evidenced by lower end expiratory and end inspiratory lung volumes during exercise (p<0.05). Prevalence of expFL (8 OB vs 2 HW, p=0.028) and mean expFL (14.9±21.9 vs 5.32±14.6% VT, p=0.043, in OB and HW) were greater in OB. After exercise training, mean increase in the distance achieved during the 6MWT was 64.5 meters (95%CI: 28.1-100.9, p=0.014) and mean decrease in exertional breathlessness was 1.62 (95%CI: 0.47-2.71, p=0.05). Obese adolescents breathed at higher lung volumes, as evidenced by the increase in end inspiratory lung volume from rest to 6-min exercise (9.9±13.4 vs 20.0±13.6%TLC, p<0.05). Improved performance was associated with improved change in end inspiratory lung volume from rest to 6-min exercise (r=0.65, p=0.025). Our results suggest that exercise training can improve breathing strategy during submaximal exercise in obese adolescents and that this increase is associated with greater exercise performance. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Urea enhances cell lysis of Schizosaccharomyces pombe ura4 mutants.

    Science.gov (United States)

    Nishino, Kohei; Kushima, Misaki; Kaino, Tomohiro; Matsuo, Yasuhiro; Kawamukai, Makoto

    2017-07-01

    Cell lysis is induced in Schizosaccharomyces pombe ∆ura4 cells grown in YPD medium, which contains yeast extract, polypeptone, and glucose. To identify the medium components that induce cell lysis, we first tested various kinds of yeast extracts from different suppliers. Cell lysis of ∆ura4 cells on YE medium was observed when yeast extracts from OXOID, BD, Oriental, and Difco were used, but not when using yeast extract from Kyokuto. To determine which compounds induced cell lysis, we subjected yeast extract and polypeptone to GC-MS analysis. Ten kinds of compounds were detected in OXOID and BD yeast extracts, but not in Kyokuto yeast extract. Among them was urea, which was also present in polypeptone, and it clearly induced cell lysis. Deletion of the ure2 gene, which is responsible for utilizing urea, abolished the lytic effect of urea. The effect of urea was suppressed by deletion of pub1, and a similar phenotype was observed in the presence of polypeptone. Thus, urea is an inducer of cell lysis in S. pombe ∆ura4 cells.

  5. Medical Issues: Breathing

    Science.gov (United States)

    ... Information Packets Equipment Pool Living With SMA Medical Issues Palliative Breathing Orthopedics Nutrition Equipment Daily Life At ... curesma.org > support & care > living with sma > medical issues > breathing Breathing Breathing problems are the most common ...

  6. Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing.

    Science.gov (United States)

    Donaldsson, Snorri; Falk, Markus; Jonsson, Baldvin; Drevhammar, Thomas

    2015-01-01

    The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

  7. 21 CFR 184.1923 - Urea.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Urea. 184.1923 Section 184.1923 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1923 Urea. (a) Urea (CO(NH2)2, CAS Reg. No. 57-13-6) is the diamide of...

  8. Thermoplastic poly(urethane urea)s from novel, bio-based amorphous polyester diols

    NARCIS (Netherlands)

    Tang, D.; Noordover, B.A.J.; Sablong, R.J.; Koning, C.E.

    2012-01-01

    In this study, two novel, bio-based, amorphous polyester diols, namely poly(1,2-dimethylethylene adipate) (PDMEA) and poly(1,2-dimethylethylene succinate) (PDMES) are used to prepare thermoplastic poly(urethane urea)s (TPUUs). Interestingly, the TPUUs based on PDMEA show similar thermal and

  9. Android integrated urea biosensor for public health awareness

    Directory of Open Access Journals (Sweden)

    Pranali P. Naik

    2015-03-01

    Full Text Available Integration of a biosensor with a wireless network on the Android 4.2.1 (Jelly Bean platform has been demonstrated. The present study reports an android integrated user friendly Flow injection analysis-Enzyme thermistor (FIA-ET urea biosensor system. This android-integrated biosensor system will facilitate enhanced consumer health and awareness alongside abridging the gap between the food testing laboratory and the concerned higher authorities. Data received from a flow injection mode urea biosensor has been exploited as an integration point among the analyst, the food consumer and the responsible higher authorities. Using the urea biosensor as an example, an alarm system has also been demonstrated both graphically and through text message on a mobile handset. The presented sensor integrated android system will also facilitate decision making support system in various fields of food quality monitoring and clinical analysis.

  10. Ventilatory muscle endurance training in quadriplegia: effects on breathing pattern.

    Science.gov (United States)

    Loveridge, B; Badour, M; Dubo, H

    1989-10-01

    We examined the effects of ventilatory muscle endurance training on resting breathing pattern in 12 C6-C7 traumatic quadriplegics at least 1 year post-injury. All subjects had complete motor loss below the lesion level. Subjects were randomly assigned to a training (N = 6), or a control group (N = 6). Baseline tests included measurement of resting ventilation and breathing pattern using mercury in rubber strain gauges for 20 minutes in a seated position; maximum inspiratory mouth pressure (MIP) at FRC, and sustainable inspiratory mouth pressure for 10 minutes (SIP); lung volumes, and arterial blood gases (ABG's). The training protocol consisted of breathing through an inspiratory resistor equivalent to 85% SIP for 15 minutes twice daily, 5 days a week for 8 weeks. Both trainers and controls attended the lab every 2 weeks for reassessment of MIP and SIP and the inspiratory resistance was increased in the training group as SIP increased. At the end of 8 weeks, baseline tests were repeated. All subjects had normal ABG's. There was a significant increase in mean MIP and SIP in both the control group (30% +/- 19% and 31% +/- 18% respectively), and in the training group (42% +/- 24% and 78% +/- 49% respectively). Although the absolute values for both MIP and SIP were greater in the training group than in the control group, the differences were not significant. The alterations in resting breathing pattern were also the same in both groups. Mean frequency decreased significantly in the control group (20.2/minute to 16.9/minute) and, while insignificant, the change in frequency in the training group was the same, 19.4/minute to 16.4/minute. Mean tidal volume (Vt) increased 18.2% of baseline Vt in the control group and 17.0% baseline in the trainers, resulting in no change in minute ventilation. As MIP and SIP increased similarly in both groups, the data from the control and trainers was pooled and timing changes re-evaluated pre- and post-study. A significant decrease in

  11. Cultural values and random breath tests as moderators of the social influence on drunk driving in 15 countries.

    Science.gov (United States)

    Cestac, Julien; Kraïem, Sami; Assailly, Jean-Pascal

    2016-02-01

    The social influence on drunk driving has been previously observed in several countries. It is noteworthy, however, that the prevalence of alcohol in road fatalities is not the same in all countries. The present study aimed to explore whether cultural values and the number of roadside breath tests moderate the link between the perceived drunk driving of one's peers and self-reported behavior. Based on the European survey SARTRE 4, the responses of 10,023 car drivers from 15 countries were analyzed. Two cultural values, "tradition" and "conformism," were identified as possibly being linked to social influence. Country scores for these values were taken from the European Social Survey. The number of random roadside breath tests per inhabitant was used as an indicator of drunk-driving enforcement in each country. A hierarchical multilevel modeling analysis confirmed the link between friends' drunk driving and one's own drunk driving in all countries, but the strength of the link was much stronger in some countries (e.g., Italy, Cyprus, and Israel) than in others (e.g., Finland, Estonia, and Sweden). Both the measured value of "tradition" and the number of alcohol breath tests were found to moderate the link between friends' and one's own drunk driving. European stakeholders should take into account cultural specificities of target countries when designing campaigns against drunk driving. Copyright © 2015. Published by Elsevier Ltd.

  12. Synthesis of 15N-enriched fertilizers. Pt. II. Synthesis of 15N-enriched urea

    International Nuclear Information System (INIS)

    Bondassolli, J.A.; Trivelin, P.C.O.; Mortatti, J.; Victoria, R.L.

    1988-01-01

    The results of studies on the production of 15 N-urea through the reaction between 15 N-enriched anhidrous ammonia, carbon monoxide and sulfur, using hydrogen sulfite as a auto catalizers and methyl alcohol as a liquid reaction medium is presented. The influence of the quantities of reagents on final yield of synthesised urea were studied. Analysis of the cost of 5 Atoms % 15 N-enriched urea were made. (M.A.C.) [pt

  13. Kidney motion during free breathing and breath hold for MR-guided radiotherapy

    International Nuclear Information System (INIS)

    Stam, Mette K; Van Vulpen, Marco; Intven, Martijn; Crijns, Sjoerd P M; Lagendijk, Jan J W; Raaymakers, Bas W; Barendrecht, Maurits M; Zonnenberg, Bernard A

    2013-01-01

    Current treatments for renal cell carcinoma have a high complication rate due to the invasiveness of the treatment. With the MRI-linac it may be possible to treat renal tumours non-invasively with high-precision radiotherapy. This is expected to reduce complications. To deliver a static dose distribution, radiation gating will be used. In this study the reproducibility and efficiency of free breathing gating and a breath hold treatment of the kidney was investigated. For 15 patients with a renal lesion the kidney motion during 2 min of free breathing and 10 consecutive expiration breath holds was studied with 2D cine MRI. The variability in kidney expiration position and treatment efficiency for gating windows of 1 to 20 mm was measured for both breathing patterns. Additionally the time trend in free breathing and the variation in expiration breath hold kidney position with baseline shift correction was determined. In 80% of the patients the variation in expiration position during free breathing is smaller than 2 mm. No clinically relevant time trends were detected. The variation in expiration breath hold is for all patients larger than the free breathing expiration variation. Gating on free breathing is, for gating windows of 1 to 5 mm more efficient than breath hold without baseline correction. When applying a baseline correction to the breath hold it increases the treatment efficiency. The kidney position is more reproducible in expiration free breathing than non-guided expiration breath hold. For small gating windows it is also more time efficient. Since free breathing also seems more comfortable for the patients it is the preferred breathing pattern for MRI-Linac treatments of the kidney. (paper)

  14. Improvement of Egyptian vacuum distillates by urea dewaxing

    Directory of Open Access Journals (Sweden)

    Ehssan M.R. Nassef

    2015-09-01

    Full Text Available The dewaxing of paraffinic lube stocks is an essential step in the production of lubricants to improve the operability of machines especially in winter. The present work deals with study of the urea dewaxing process of two types of Egyptian vacuum distillates. The effect of different compositions of methanol to water saturated with urea and yield of the oil, percent of wax, pour point, refractive index, viscosity, viscosity index and specific gravity of the oil produced from the two types of distillates (I and II were evaluated. The operating conditions of the urea adduct formation with n-paraffins using methanol to water mixture achieved the best pour point at −3.88 °C from an initial temperature of 4.4 °C for distillate I at (25/75 methanol to water. At the same ratio of methanol to water the best specific gravity of oil produced changed from 0.865 to 0.867, with viscosity index of 80. Percent yield of 50% for oil and percent wax of 50% were obtained. Results for distillate II, of higher specific gravity, are comparatively higher than those for distillate I. Experiments were carried out at room temperature.

  15. Potentiometric Urea Biosensor Based on an Immobilised Fullerene-Urease Bio-Conjugate

    Directory of Open Access Journals (Sweden)

    Kasra Saeedfar

    2013-12-01

    Full Text Available A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate (PnBA membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10−3 M to 8.28 × 10−5 M. The biosensor’s sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor’s response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days.

  16. Effects of nitrogen supply on inter-organ fluxes of urea-N and renal urea-N kinetics in lactating Holstein cows

    DEFF Research Database (Denmark)

    Røjen, Betina Amdisen; Theil, Peter Kappel; Kristensen, Niels Bastian

    2011-01-01

    The effects of decreasing ruminal urea infusion in lactating dairy cows fed a basal diet deficient in rumen degradable protein on inter-organ urea-N fluxes, epithelial urea-N extraction, and renal urea-N kinetics were investigated. Eight Danish Holstein cows fitted with a ruminal cannula...... and permanent indwelling catheters in the major splanchnic blood vessels and the gastrosplenic vein were used. The cows were randomly allocated to a triplicate incomplete 3 × 3 Latin square design with 14-d periods. Treatments were continuous ventral ruminal infusion of water, 4.1 g of feed urea/kg of dry...... matter intake, and 8.5 g of feed urea/kg of dry matter intake. Dry matter intake and milk yield decreased linearly with decreasing urea infusion. Arterial blood urea-N and ruminal ammonia concentrations decreased linearly with decreasing urea infusion. In absolute amounts, the urea-N recycling did...

  17. Positive Result by Serology Indicates Active Helicobacter pylori Infection in Patients with Atrophic Gastritis

    OpenAIRE

    Kokkola, Arto; Rautelin, Hilpi; Puolakkainen, Pauli; Sipponen, Pentti; Färkkilä, Martti; Haapiainen, Reijo; Kosunen, Timo U.

    1998-01-01

    Patients with atrophic corpus gastritis and elevated Helicobacter pylori antibody titers but 13C-urea breath test (13C-UBT) and histology results negative for H. pylori were randomized into eradication therapy or follow-up only. Antibody levels decreased significantly in six out of seven patients in the eradication group, while in the follow-up group, the titers declined in only one out of eight patients. In patients with atrophic corpus gastritis, positive serology results may indicate an on...

  18. High frequency mechanical ventilation affects respiratory system mechanics differently in C57BL/6J and BALB/c adult mice.

    Science.gov (United States)

    Hadden, Hélène

    2013-01-15

    We tested the hypothesis that high frequency ventilation affects respiratory system mechanical functions in C57BL/6J and BALB/c mice. We measured respiratory mechanics by the forced oscillation technique over 1h in anesthetized, intubated, ventilated BALB/c and C57BL/6J male mice. We did not detect any change in airway resistance, Rn, tissue damping, G, tissue elastance, H and hysteresivity, eta in BALB/c mice during 1h of ventilation at 150 or at 450 breaths/min; nor did we find a difference between BALB/c mice ventilated at 150 breaths/min compared with 450 breaths/min. Among C57BL/6J mice, except for H, all parameters remained unchanged over 1h of ventilation in mice ventilated at 150 breaths/min. However, after 10 and 30 min of ventilation at 450 breaths/min, Rn, and respiratory system compliance were lower, and eta was higher, than their starting value. We conclude that high frequency mechanical ventilation affects respiratory system mechanics differently in C57BL/6J and BALB/c adult mice. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Salivary creatinine and urea analysis in patients with chronic kidney disease: a case control study.

    Science.gov (United States)

    Lasisi, Taye Jemilat; Raji, Yemi Raheem; Salako, Babatunde Lawal

    2016-01-16

    Many metabolic changes develop in patients with chronic kidney disease which often necessitate frequent biochemical analysis of blood. Saliva analysis as an alternative to blood has many advantages. The aims of this study were to evaluate levels of salivary creatinine and urea in patients with chronic kidney disease in comparison to healthy individuals; to determine correlation between salivary creatinine/urea and blood creatinine/urea and to evaluate the diagnostic potential of saliva. A case control study, involving 50 patients with late stage chronic kidney disease and 49 healthy individuals as control. Blood and saliva samples were analyzed for urea and creatinine levels. Data are presented as median with interquartile range and compared using Independent Samples Mann Whitney U test. Correlation between plasma and salivary creatinine as well as urea was determined using Spearman's correlation test. Receiver operating characteristics (ROC) analysis was done to determine the diagnostic ability of salivary creatinine and urea and cut-off values were established. Median salivary creatinine levels were 2.60 mg/dl and 0.20 mg/dl while median salivary urea levels were 92.00 mg/dl and 20.50 mg/dl in patients with chronic kidney disease and controls respectively. Salivary levels of creatinine and urea were significantly elevated in chronic kidney disease patients (p creatinine as well as urea levels. Total areas under the curve for salivary creatinine and urea were 0.97 and 0.89 respectively. Cut-off values for salivary creatinine and urea were 0.55 mg/dl and 27.50 mg/dl respectively which gave sensitivity and specificity of 94 % and 85 % for creatinine; as well as 86 % and 93 % for urea. Findings of this study suggest that analysis of salivary creatinine and urea in patients with chronic kidney disease reflects their levels in blood. Hence, salivary creatinine and urea could be used as diagnostic biomarkers of chronic kidney disease.

  20. Breath acetone monitoring by portable Si:WO3 gas sensors

    International Nuclear Information System (INIS)

    Righettoni, Marco; Tricoli, Antonio; Gass, Samuel; Schmid, Alex; Amann, Anton; Pratsinis, Sotiris E.

    2012-01-01

    Highlights: ► Portable sensors were developed and tested for monitoring acetone in the human breath. ► Acetone concentrations down to 20 ppb were measured with short response times ( 3 nanostructured films was developed. The chamber volume was miniaturized while reaction-limited and transport-limited gas flow rates were identified and sensing temperatures were optimized resulting in a low detection limit of acetone (∼20 ppb) with short response (10–15 s) and recovery times (35–70 s). Furthermore, the sensor signal (response) was robust against variations of the exhaled breath flow rate facilitating application of these sensors at realistic relative humidities (80–90%) as in the human breath. The acetone content in the breath of test persons was monitored continuously and compared to that of state-of-the-art proton transfer reaction mass spectrometry (PTR-MS). Such portable devices can accurately track breath acetone concentration to become an alternative to more elaborate breath analysis techniques.

  1. A perfusion study of the handling of urea and urea analogues by the gills of the dogfish shark (Squalus acanthias).

    Science.gov (United States)

    Wood, Chris M; Liew, Hon Jung; De Boeck, Gudrun; Walsh, Patrick J

    2013-01-01

    The branchial mechanism of urea retention in elasmobranchs was investigated using an in vitro isolated-perfused head preparation, as well as in vivo samples, in the spiny dogfish shark. Both in vivo and in control saline perfusions containing 350 mmol L(-1) urea, calculated intracellular urea concentrations in gill epithelial cells were close to extracellular concentrations. Urea efflux to the external water fell only non-significantly, and calculated gill intracellular urea concentration did not change when perfusate urea concentration was reduced from 350 to 175 mmol L(-1) with osmotic compensation by 175 mmol L(-1) mannitol. However, when the urea analogues thiourea or acetamide were present in the perfusate at concentrations equimolar (175 mmol L(-1)) to those of urea (175 mmol L(-1)), urea efflux rates were increased 4-fold and 6.5-fold respectively, and calculated gill intracellular urea concentrations were depressed by about 55%. Analogue efflux rates were similar to urea efflux rates. Previous studies have argued that either the basolateral or apical membranes provided the limiting permeability barrier, and/or that a back-transporter on the basolateral membranes of gill cells is responsible for urea retention. The present results provide new evidence that the apical membrane is the limiting factor in maintaining gill urea impermeability, and raise the prospect that a urea back-transporter, which can be competitively inhibited by thiourea and acetamide, operates at the apical membrane.

  2. A perfusion study of the handling of urea and urea analogues by the gills of the dogfish shark (Squalus acanthias

    Directory of Open Access Journals (Sweden)

    Chris M. Wood

    2013-02-01

    Full Text Available The branchial mechanism of urea retention in elasmobranchs was investigated using an in vitro isolated-perfused head preparation, as well as in vivo samples, in the spiny dogfish shark. Both in vivo and in control saline perfusions containing 350 mmol L−1 urea, calculated intracellular urea concentrations in gill epithelial cells were close to extracellular concentrations. Urea efflux to the external water fell only non-significantly, and calculated gill intracellular urea concentration did not change when perfusate urea concentration was reduced from 350 to 175 mmol L−1 with osmotic compensation by 175 mmol L−1 mannitol. However, when the urea analogues thiourea or acetamide were present in the perfusate at concentrations equimolar (175 mmol L−1 to those of urea (175 mmol L−1, urea efflux rates were increased 4-fold and 6.5-fold respectively, and calculated gill intracellular urea concentrations were depressed by about 55%. Analogue efflux rates were similar to urea efflux rates. Previous studies have argued that either the basolateral or apical membranes provided the limiting permeability barrier, and/or that a back-transporter on the basolateral membranes of gill cells is responsible for urea retention. The present results provide new evidence that the apical membrane is the limiting factor in maintaining gill urea impermeability, and raise the prospect that a urea back-transporter, which can be competitively inhibited by thiourea and acetamide, operates at the apical membrane.

  3. Slow release coating remedy for nitrogen loss from conventional urea: a review.

    Science.gov (United States)

    Naz, Muhammad Yasin; Sulaiman, Shaharin Anwar

    2016-03-10

    Developing countries are consuming major part of the global urea production with an anticipated nitrogen use efficiency of 20 to 35%. The release of excess nitrogen in the soil is not only detrimental to the environment but also lessens the efficiency of the conventional urea. The urea performance can be enhanced by encapsulating it with slow release coating materials and synchronizing the nutrients' release with the plant up-taking. However, the present cost of most of the coated fertilizers is considerably higher than the conventional fertilizers. The high cost factor prevents their widespread use in mainstream agriculture. This paper documents a review of literature related to the global urea market, issues pertaining to the conventional urea use, natural and synthetic materials for slow release urea and fluidized bed spray coating process. The aim of the current review is to develop technical understanding of the conventional and non-conventional coating materials and associated spray coating mechanism for slow release urea production. The study also investigated the potential of starch as the coating material in relation to the coatings tested previously for controlled release fertilizers. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Corrosion Behavior of Candidate Materials Used for Urea Hydrolysis Equipment in Coal-Fired Selective Catalytic Reduction Units

    Science.gov (United States)

    Lu, Jintao; Yang, Zhen; Zhang, Bo; Huang, Jinyang; Xu, Hongjie

    2018-05-01

    Corrosion tests were performed in the laboratory in order to assess the corrosion resistance of candidate materials used in urea hydrolysis equipment. The materials to be evaluated were exposed at 145 °C for 1000 h. Alloys 316L, 316L Mod., HR3C, Inconel 718, and TC4 were evaluated. Additionally, aluminide and chromate coatings applied to a 316L substrate were examined. After exposure, the mass changes in the test samples were measured by a discontinuous weighing method, and the morphologies, compositions, and phases of the corrosion products were analyzed using scanning electron microscopy, energy-dispersive spectroscopy, and x-ray diffraction. Results indicated that continuous pitting and dissolution corrosion were the main failure modes for 316L stainless steel. 316L Mod. and HR3C alloy showed better corrosion resistance than 316L due to their relatively high Cr contents, but HR3C exhibited a strong tendency toward intergranular corrosion. Inconel 718, TC4, and aluminide and chromate coating samples showed similar corrosion processes: only depositions formed by hydrothermal reactions were observed. Based on these results, a possible corrosion process in the urea hydrolysis environment was discussed for these candidate materials and questions to be clarified were proposed.

  5. Mutagenic activity of N-nitrosoethylene urea in higher plants. [C. cappilaris L

    Energy Technology Data Exchange (ETDEWEB)

    Sal' nikova, T.V.; Grigorova, N.V.; Laputin, D.L.; Shustova, L.L., Zazimko, V.V.; Shustov, G.V.; Kostyanovskiy, R.G.

    1984-04-01

    Cytopathogenetic effect of N-nitrosoethylene urea (NETM) on common wheat and C. cappilaris L. are studied. Air-dried wheat seeds were treated with 1 of 5 concentrations (0.1-0.01%) of NETM for 18 hours at pH 5.7 or 7.0. Treatment of seeds with NETM reduced the germinating power significantly at pH 5.7, especially at high concentrations of NETM. NETM is also a highly effective chemical mutagen. Maximum mutagenic effect appears at pH 7.0. NETM greatly reduced mitotic activity of wheat and C. cappilaris L. which is typical for alkylating type mutagens. The aberration rate is rather high for both objects studied. In both the anaphase and metaphase method of calculating chromosomal injuries, a great percentage of the total number of aberrations are chromatid type reconstructions which indicates predominance of the alkylating action of NETM. Wheat affected by NETM has a large number of anaphase cells with lagging chromosome which is atypical for alkylating type mutagens. This may be explained by the effect of NETM on centromeric and precentromeric parts of chromosomes and spindle filaments. NETM is an alkylating agent rather than a carbamoylating agent. It is a highly active and slightly toxic mutagen. 25 references, 1 figure.

  6. Effects of bentonite on plasma urea and creatinine of wistar albino rats.

    African Journals Online (AJOL)

    The in vivo effect of Nigerian calcium bentonite clay on wistar albino rat plasma urea and creatinine levels were investigated. The rats were fed for a period of four weeks with varying concentrations of the bentonite clay, and the urea and creatinine levels determined using spectrophotometric methods. Test results showed ...

  7. Urea adsorption by activated carbon prepared from palm kernel shell

    Science.gov (United States)

    Ooi, Chee-Heong; Sim, Yoke-Leng; Yeoh, Fei-Yee

    2017-07-01

    Dialysis treatment is crucial for patients suffer from renal failure. The dialysis system removes the uremic toxin to a safe level in a patient's body. One of the major limitations of the current hemodialysis system is the capability to efficiently remove uremic toxins from patient's body. Nanoporous materials can be applied to improve the treatment. Palm kernel shell (PKS) biomass generated from palm oil mills can be utilized to prepare high quality nanoporous activated carbon (AC) and applied for urea adsorption in the dialysis system. In this study, AC was prepared from PKS via different carbonization temperatures and followed by carbon dioxide gas activation processes. The physical and chemical properties of the samples were studied. The results show that the porous AC with BET surface areas ranging from 541 to 622 m2g-1 and with total pore volumes varying from 0.254 to 0.297 cm3g-1, are formed with different carbonization temperatures. The equilibrium constant for urea adsorption by AC samples carbonized at 400, 500 and 600 °C are 0.091, 0.287 and 0.334, respectively. The increase of carbonization temperatures from 400 to 600 °C resulted in the increase in urea adsorption by AC predominantly due to increase in surface area. The present study reveals the feasibility of preparing AC with good porosity from PKS and potentially applied in urea adsorption application.

  8. Role of thin descending limb urea transport in renal urea handling and the urine concentrating mechanism

    Science.gov (United States)

    Lei, Tianluo; Zhou, Lei; Layton, Anita T.; Zhou, Hong; Zhao, Xuejian; Bankir, Lise

    2011-01-01

    Urea transporters UT-A2 and UT-B are expressed in epithelia of thin descending limb of Henle's loop and in descending vasa recta, respectively. To study their role and possible interaction in the context of the urine concentration mechanism, a UT-A2 and UT-B double knockout (UT-A2/B knockout) mouse model was generated by targeted deletion of the UT-A2 promoter in embryonic stem cells with UT-B gene knockout. The UT-A2/B knockout mice lacked detectable UT-A2 and UT-B transcripts and proteins and showed normal survival and growth. Daily urine output was significantly higher in UT-A2/B knockout mice than that in wild-type mice and lower than that in UT-B knockout mice. Urine osmolality in UT-A2/B knockout mice was intermediate between that in UT-B knockout and wild-type mice. The changes in urine osmolality and flow rate, plasma and urine urea concentration, as well as non-urea solute concentration after an acute urea load or chronic changes in protein intake suggested that UT-A2 plays a role in the progressive accumulation of urea in the inner medulla. These results suggest that in wild-type mice UT-A2 facilitates urea absorption by urea efflux from the thin descending limb of short loops of Henle. Moreover, UT-A2 deletion in UT-B knockout mice partially remedies the urine concentrating defect caused by UT-B deletion, by reducing urea loss from the descending limbs to the peripheral circulation; instead, urea is returned to the inner medulla through the loops of Henle and the collecting ducts. PMID:21849488

  9. Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing.

    Directory of Open Access Journals (Sweden)

    Snorri Donaldsson

    Full Text Available The ability to determine airflow during nasal CPAP (NCPAP treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing.Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically.The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance.The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

  10. Mapleson's Breathing Systems.

    Science.gov (United States)

    Kaul, Tej K; Mittal, Geeta

    2013-09-01

    Mapleson breathing systems are used for delivering oxygen and anaesthetic agents and to eliminate carbon dioxide during anaesthesia. They consist of different components: Fresh gas flow, reservoir bag, breathing tubes, expiratory valve, and patient connection. There are five basic types of Mapleson system: A, B, C, D and E depending upon the different arrangements of these components. Mapleson F was added later. For adults, Mapleson A is the circuit of choice for spontaneous respiration where as Mapleson D and its Bains modifications are best available circuits for controlled ventilation. For neonates and paediatric patients Mapleson E and F (Jackson Rees modification) are the best circuits. In this review article, we will discuss the structure of the circuits and functional analysis of various types of Mapleson systems and their advantages and disadvantages.

  11. Determination of urea content in urea cream by centrifugal partition chromatography

    Directory of Open Access Journals (Sweden)

    Ying-Qun Wang

    2016-04-01

    Full Text Available The objective of this study is to establish a centrifugal partition chromatography (CPC method for determination of the urea ingredient in urea cream. The mechanism of this method is that urea is determined by UV detector at 430 nm after being extracted from the cream and derivatized on line via Ehrlich reaction in rotor of CPC, where the reaction products dissolve in the mobile phase and the cream matrix retains in the stationary phase. The mixed solvent consisting of n-hexane, methanol, hydrochloric acid and p-dimethylaminobenzaldehyde with a ratio of 1000 mL:1000 mL:18 mL:2.0 g is used for solvent system of CPC. The CPC method proposed offers good precision and convenience without complex sample pretreatment processes.

  12. An optimized and simplified method for analysing urea and ammonia in freshwater aquaculture systems

    DEFF Research Database (Denmark)

    Larsen, Bodil Katrine; Dalsgaard, Anne Johanne Tang; Pedersen, Per Bovbjerg

    2015-01-01

    This study presents a simple urease method for analysis of ammonia and urea in freshwater aquaculture systems. Urea is hydrolysed into ammonia using urease followed by analysis of released ammonia using the salicylate-hypochlorite method. The hydrolysis of urea is performed at room temperature...... and without addition of a buffer. A number of tests were performed on water samples obtained from a commercial rainbow trout farm to determine the optimal urease concentration and time for complete hydrolysis. One mL of water sample was spiked with 1.3 mL urea at three different concentrations: 50 lg L 1, 100...... lg L 1 and 200 lg L 1 urea-N. In addition, five concentrations of urease were tested, ranging from 0.1 U mL 1 to 4 U mL 1. Samples were hydrolysed for various time periods ranging from 5 to 120 min. A urease concentration of 0.4 U mL 1 and a hydrolysis period of 120 min gave the best results, with 99...

  13. Urea-molasses liquid diet feeding for growth produion in cattle and buffalo

    International Nuclear Information System (INIS)

    Pathak, N.N.; Ranjhan, S.K.; Singh, U.B.

    1974-01-01

    As a part of the study to find the utilization of urea-molasses liquid for growth and maintenance in cattle and buffaloes, production rate of volatile fatty acids (VFAs) was measured by single injection isotope dilution technique using 1-2 14 C-acetate in adult cattle and buffaloes fed ad libitum urea-molasses diet with restricted wheat straw and intact protein. (M.G.B.)

  14. Interaction between dietary content of protein and sodium chloride on milk urea concentration, urinary urea excretion, renal recycling of urea, and urea transfer to the gastrointestinal tract in dairy cows.

    Science.gov (United States)

    Spek, J W; Bannink, A; Gort, G; Hendriks, W H; Dijkstra, J

    2013-09-01

    Dietary protein and salt affect the concentration of milk urea nitrogen (MUN; mg of N/dL) and the relationship between MUN and excretion of urea nitrogen in urine (UUN; g of N/d) of dairy cattle. The aim of the present study was to examine the effects of dietary protein and sodium chloride (NaCl) intake separately, and their interaction, on MUN and UUN, on the relationship between UUN and MUN, on renal recycling of urea, and on urea transfer to the gastrointestinal tract. Twelve second-parity cows (body weight of 645±37 kg, 146±29 d in milk, and a milk production of 34.0±3.28 kg/d), of which 8 were previously fitted with a rumen cannula, were fitted with catheters in the urine bladder and jugular vein. The experiment had a split-plot arrangement with dietary crude protein (CP) content as the main plot factor [116 and 154 g of CP/kg of dry matter (DM)] and dietary NaCl content as the subplot factor (3.1 and 13.5 g of Na/kg of DM). Cows were fed at 95% of the average ad libitum feed intake of cows receiving the low protein diets. Average MUN and UUN were, respectively, 3.90 mg of N/dL and 45 g of N/d higher for the high protein diets compared with the low protein diets. Compared with the low NaCl diets, MUN was, on average, 1.74 mg of N/dL lower for the high NaCl diets, whereas UUN was unaffected. We found no interaction between dietary content of protein and NaCl on performance characteristics or on MUN, UUN, urine production, and renal clearance characteristics. The creatinine clearance rate was not affected by dietary content of protein and NaCl. Urea transfer to the gastrointestinal tract, expressed as a fraction of plasma urea entry rate, was negatively related to dietary protein, whereas it was not affected by dietary NaCl content. We found no interaction between dietary protein and NaCl content on plasma urea entry rate and gastrointestinal urea entry rate or their ratio. The relationship between MUN and UUN was significantly affected by the class variable

  15. Effects of low temperature on breathing pattern and ventilatory responses during hibernation in the golden-mantled ground squirrel.

    Science.gov (United States)

    Webb, Cheryl L; Milsom, William K

    2017-07-01

    During entrance into hibernation in golden-mantled ground squirrels (Callospermophilus lateralis), ventilation decreases as metabolic rate and body temperature fall. Two patterns of respiration occur during deep hibernation. At 7 °C body temperature (T b ), a breathing pattern characterized by episodes of multiple breaths (20.6 ± 1.9 breaths/episode) separated by long apneas or nonventilatory periods (T nvp ) (mean = 11.1 ± 1.2 min) occurs, while at 4 °C T b , a pattern in which breaths are evenly distributed and separated by a relatively short T nvp (0.5 ± 0.05 min) occurs. Squirrels exhibiting each pattern have similar metabolic rates and levels of total ventilation (0.2 and 0.23 ml O 2 /hr/kg and 0.11 and 0.16 ml air/min/kg, respectively). Squirrels at 7 °C T b exhibit a significant hypoxic ventilatory response, while squirrels at 4 °C T b do not respond to hypoxia at any level of O 2 tested. Squirrels at both temperatures exhibit a significant hypercapnic ventilatory response, but the response is significantly reduced in the 4 °C T b squirrels. Carotid body denervation has little effect on the breathing patterns or on the hypercapnic ventilatory responses. It does reduce the magnitude and threshold for the hypoxic ventilatory response. Taken together the data suggest that (1) the fundamental rhythm generator remains functional at low temperatures; (2) the hypercapnic ventilatory response arises from central chemoreceptors that remain functional at very low temperatures; (3) the hypoxic ventilatory response arises from both carotid body and aortic chemoreceptors that are silenced at lower temperatures; and (4) there is a strong correlation between breathing pattern and chemosensitivity.

  16. Radiochemical investigation of the bioaccumulation of urea by the alga Hydrodictyon reticulatum

    International Nuclear Information System (INIS)

    Havelka, M.; Stary, J.; Kratzer, K.

    1987-01-01

    It is found that the bioaccumulation of 14 C-urea in the light is connected with the increase of pH-value of the external medium, of the intracellular concentration of ammonium ions and with the decrease of the intracellular concentration of potassium ions. The uptake rate does not depend on the concentration of urea in the range from 0.1 to 2.0 mmol dm -3 and it has a broad maximum at pH 6.5-8.0. The uptake rate of urea is a little higher compared with nitrite or nitrate anions, however it is at least three times lower in comparison with that of ammonium or hydrocarbonate ions. The uptake of urea in the dark leads to the increase of the intracellular concentration of ammonium ions, however, carbon dioxide formed is released from the cell. (author) 7 refs

  17. The use of active breathing control (ABC) to reduce margin for breathing motion

    International Nuclear Information System (INIS)

    Wong, John W.; Sharpe, Michael B.; Jaffray, David A.; Kini, Vijay R.; Robertson, John M.; Stromberg, Jannifer S.; Martinez, Alavro A.

    1999-01-01

    Purpose: For tumors in the thorax and abdomen, reducing the treatment margin for organ motion due to breathing reduces the volume of normal tissues that will be irradiated. A higher dose can be delivered to the target, provided that the risk of marginal misses is not increased. To ensure safe margin reduction, we investigated the feasibility of using active breathing control (ABC) to temporarily immobilize the patient's breathing. Treatment planning and delivery can then be performed at identical ABC conditions with minimal margin for breathing motion. Methods and Materials: An ABC apparatus is constructed consisting of 2 pairs of flow monitor and scissor valve, 1 each to control the inspiration and expiration paths to the patient. The patient breathes through a mouth-piece connected to the ABC apparatus. The respiratory signal is processed continuously, using a personal computer that displays the changing lung volume in real-time. After the patient's breathing pattern becomes stable, the operator activates ABC at a preselected phase in the breathing cycle. Both valves are then closed to immobilize breathing motion. Breathing motion of 12 patients were held with ABC to examine their acceptance of the procedure. The feasibility of applying ABC for treatment was tested in 5 patients by acquiring volumetric scans with a spiral computed tomography (CT) scanner during active breath-hold. Two patients had Hodgkin's disease, 2 had metastatic liver cancer, and 1 had lung cancer. Two intrafraction ABC scans were acquired at the same respiratory phase near the end of normal or deep inspiration. An additional ABC scan near the end of normal expiration was acquired for 2 patients. The ABC scans were also repeated 1 week later for a Hodgkin's patient. In 1 liver patient, ABC scans were acquired at 7 different phases of the breathing cycle to facilitate examination of the liver motion associated with ventilation. Contours of the lungs and livers were outlined when applicable

  18. Rapid shallow breathing

    Science.gov (United States)

    Tachypnea; Breathing - rapid and shallow; Fast shallow breathing; Respiratory rate - rapid and shallow ... Shallow, rapid breathing has many possible medical causes, including: Asthma Blood clot in an artery in the ...

  19. 40 CFR 721.9892 - Alkylated urea.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylated urea. 721.9892 Section 721... Alkylated urea. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an alkylated urea (PMN P-93-1649) is subject to reporting under this...

  20. 40 CFR 721.9928 - Urea, tetraethyl-.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Urea, tetraethyl-. 721.9928 Section... Substances § 721.9928 Urea, tetraethyl-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as urea, tetraethyl- (PMN P-94-1017; CAS No. 1187-03-7) is...

  1. Effect of synthesis solvent on the breathing behavior of MIL-53(Al).

    Science.gov (United States)

    Mounfield, William P; Walton, Krista S

    2015-06-01

    This work reports the effect of using dimethylformamide (DMF) as the solvent for synthesizing MIL-53(Al). This well-known breathing MOF is typically prepared using hydrothermal methods. The two materials synthesized in DMF at 120°C and 220°C show significant deviations from the breathing behavior exhibited by the material synthesized hydrothermally. Powder X-ray diffraction confirmed that MIL-53(Al) synthesized in DMF at 120°C remains in the large-pore form under all conditions, while the other material synthesized at 220°C undergoes a more gradual breathing transition than is observed for MIL-53(Al) prepared by traditional methods. Solid-state NMR was employed to elucidate additional structural information and gain insight into the role synthesis solvent plays on breathing behavior. The CO2 and water adsorption of these large-pore stabilized materials were studied, and the differences in adsorption behavior compared to MIL-53(Al) prepared by traditional methods was discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Urea route to coat inorganic nanowires, carbon fibers and nanotubes by boron nitride

    International Nuclear Information System (INIS)

    Gomathi, A.; Ramya Harika, M.; Rao, C.N.R.

    2008-01-01

    A simple route involving urea as the nitrogen source has been employed to carry out boron nitride coating on carbon fibers, multi-walled carbon nanotubes and inorganic nanowires. The process involves heating the carbon fibers and nanotubes or inorganic nanowires in a mixture of H 3 BO 3 and urea, followed by a heat treatment at 1000 deg. C in a N 2 atmosphere. We have been able to characterize the BN coating by transmission electron microscopy as well as X-ray photoelectron spectroscopy. The urea decomposition route affords a simple method to coat boron nitride on one-dimensional nanostructures

  3. Waste-to-Chemicals for a Circular Economy: The Case of Urea Production (Waste-to-Urea).

    Science.gov (United States)

    Antonetti, Elena; Iaquaniello, Gaetano; Salladini, Annarita; Spadaccini, Luca; Perathoner, Siglinda; Centi, Gabriele

    2017-03-09

    The economics and environmental impact of a new technology for the production of urea from municipal solid waste, particularly the residue-derived fuel (RdF) fraction, is analyzed. Estimates indicate a cost of production of approximately €135 per ton of urea (internal rate of return more than 10 %) and savings of approximately 0.113 tons of CH 4 and approximately 0.78 tons of CO 2 per ton of urea produced. Thus, the results show that this waste-to-urea (WtU) technology is both economically valuable and environmentally advantageous (in terms of saving resources and limiting carbon footprint) for the production of chemicals from municipal solid waste in comparison with both the production of urea with conventional technology (starting from natural gas) and the use of RdF to produce electrical energy (waste-to-energy). A further benefit is the lower environmental impact of the solid residue produced from RdF conversion. The further benefit of this technology is the possibility to realize distributed fertilizer production. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. The urea cycle disorders.

    Science.gov (United States)

    Helman, Guy; Pacheco-Colón, Ileana; Gropman, Andrea L

    2014-07-01

    The urea cycle is the primary nitrogen-disposal pathway in humans. It requires the coordinated function of six enzymes and two mitochondrial transporters to catalyze the conversion of a molecule of ammonia, the α-nitrogen of aspartate, and bicarbonate into urea. Whereas ammonia is toxic, urea is relatively inert, soluble in water, and readily excreted by the kidney in the urine. Accumulation of ammonia and other toxic intermediates of the cycle lead to predominantly neurologic sequelae. The disorders may present at any age from the neonatal period to adulthood, with the more severely affected patients presenting earlier in life. Patients are at risk for metabolic decompensation throughout life, often triggered by illness, fasting, surgery and postoperative states, peripartum, stress, and increased exogenous protein load. Here the authors address neurologic presentations of ornithine transcarbamylase deficiency in detail, the most common of the urea cycle disorders, neuropathology, neurophysiology, and our studies in neuroimaging. Special attention to late-onset presentations is given. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  5. INFLUENCE OF ENVIRONMENTAL AND GENETICAL FACTORS ON UREA CONTENT IN HOLSTEIN BREED COWS MILK

    Directory of Open Access Journals (Sweden)

    Draženko Budimir

    2014-12-01

    Full Text Available The aims of this paper were to determine to which extent the environmental factors (order and stadium of lactation, age with the first calving, calving season, region and herd have the influence on the content of urea in milk, and connection of urea content in milk with other features of milk production with cows. The largest share of urea content in milk was recorded in the first lactation, in the period between 110 and 140 days, when it was around 23.6 mg/100 ml. In the end of the first lactation the average urea content in milk was around 21.6 mg/100 ml. The second lactation is chara¬cterized by somewhat bigger urea content, in the period immediately after calving when the highest values from all tracked lactations was recorded. The age of cows with their first calving also had an impact on urea con¬tent in milk. Cows that calved in the age from 24th to 26th month had the highest value of urea content, being 23.2 mg/100 ml for the stated period. The lowest value of urea content was recorded with cows that calved in the age of 18 months and it was below 20 mg/100 ml. Season of calving also influenced the urea content in milk. In winter season 2004 the lowest values of urea content in milk were recorded while in the autumn sea¬son of the same year the highest urea content in milk was measured (24 mg/100 ml. In the following calving season increase of urea content in milk followed. The differences in urea content in milk were determined between the counties. The highest value of heritabi-lity (0.08 was estimated by the model where, as a comparison group, the interaction between the herds and control day was used. In the research the share of variability was explained by the interaction herd-control day and it was 67%, while 25% of variability of urea con¬tent in milk remained unexplained. This model was used when estimating the breeding values. A model was also tested where the influence of herd was used as a comparison group, and by this

  6. Interaction between dietary content of protein and sodium chloride on milk urea concentration, urinary urea excretion, renal recycling of urea, and urea transfer to the gastrointestinal tract in dairy cows

    NARCIS (Netherlands)

    Spek, J.W.; Bannink, A.; Gort, G.; Hendriks, W.H.; Dijkstra, J.

    2013-01-01

    Dietary protein and salt affect the concentration of milk urea nitrogen (MUN; mg of N/dL) and the relationship between MUN and excretion of urea nitrogen in urine (UUN; g of N/d) of dairy cattle. The aim of the present study was to examine the effects of dietary protein and sodium chloride (NaCl)

  7. An electron spin resonance study on the gamma-irradiation of urea, urea- d4, 1-3-dimethylurea, 1-3-diethylurea and 1,1',3,3'-tetramthylurea

    International Nuclear Information System (INIS)

    Kang, Y.S.; McManus, H.J.D.; Kevan, L.

    1994-01-01

    Urea, urea-d 4 , 1,3-dimethylurea, 1,3-diethylurea powder and 1,1',3,3'-tetramethylurea, and their solutions in D 2 O were γ-irradiated with 0.0882 kGy both at room temperature and at 77 K. The product radicals were identified with X-band electron spin resonance, based on the g-factor and hyperfine coupling constants. The radicals formed from urea and urea-d 4 were identified as nitrogen-centered and resulted from N-H bond dissociation. The radicals produced from 1,3-dimethylurea, 1,3-diethylurea and 1,1',3,3'-tetramethylurea were identified as carbon-centered and resulted from C-H bond cleavage. The electron spin resonance signals of 1,3-dimethylurea, 1,3-diethylurea and 1,1',3,3'-tetramethylurea are similar in both the powder and D 2 O solution. The radicals observed from 1,3-dimethylurea, 1,3-diethylurea and 1,1',3,3'-tetramethylurea were identified as . NH-CH 2 , . NH-CHCH 3 and . (CH 3 )(CH 2 ), respectively. (author)

  8. Experimental investigation of urea injection parameters influence on NOx emissions from blended biodiesel-fueled diesel engines.

    Science.gov (United States)

    Mehregan, Mina; Moghiman, Mohammad

    2018-02-01

    The present work submits an investigation about the effect of urea injection parameters on NO x emissions from a four-stroke four-cylinder diesel engine fueled with B20 blended biodiesel. An L 9 (3 4 ) Taguchi orthogonal array was used to design the test plan. The results reveal that increasing urea concentration leads to lower NO x emissions. Urea flow rate increment has the same influence on NO x emission. The same result is obtained by an increase in spray angle. Also, according to the analysis of variance (ANOVA), urea concentration and then urea flow rate are the most effective design parameters on NO x emissions, while spray angle and mixing length have less influence on this pollutant emission. Finally, since the result of confirmation test is in good agreement with the predicted value based on the Taguchi technique, the predictive capability of this method in the present study could be deduced.

  9. Transcriptomic Analysis of Compromise Between Air-Breathing and Nutrient Uptake of Posterior Intestine in Loach (Misgurnus anguillicaudatus), an Air-Breathing Fish.

    Science.gov (United States)

    Huang, Songqian; Cao, Xiaojuan; Tian, Xianchang

    2016-08-01

    Dojo loach (Misgurnus anguillicaudatus) is an air-breathing fish species by using its posterior intestine to breathe on water surface. So far, the molecular mechanism about accessory air-breathing in fish is seldom addressed. Five cDNA libraries were constructed here for loach posterior intestines form T01 (the initial stage group), T02 (mid-stage of normal group), T03 (end stage of normal group), T04 (mid-stage of air-breathing inhibited group), and T05 (the end stage of air-breathing inhibited group) and subjected to perform RNA-seq to compare their transcriptomic profilings. A total of 92,962 unigenes were assembled, while 37,905 (40.77 %) unigenes were successfully annotated. 2298, 1091, and 3275 differentially expressed genes (fn1, ACE, EGFR, Pxdn, SDF, HIF, VEGF, SLC2A1, SLC5A8 etc.) were observed in T04/T02, T05/T03, and T05/T04, respectively. Expression levels of many genes associated with air-breathing and nutrient uptake varied significantly between normal and intestinal air-breathing inhibited group. Intraepithelial capillaries in posterior intestines of loaches from T05 were broken, while red blood cells were enriched at the surface of intestinal epithelial lining with 241 ± 39 cells per millimeter. There were periodic acid-schiff (PAS)-positive epithelial mucous cells in posterior intestines from both normal and air-breathing inhibited groups. Results obtained here suggested an overlap of air-breathing and nutrient uptake function of posterior intestine in loach. Intestinal air-breathing inhibition in loach would influence the posterior intestine's nutrient uptake ability and endothelial capillary structure stability. This study will contribute to our understanding on the molecular regulatory mechanisms of intestinal air-breathing in loach.

  10. Milk Urea Dynamics during its Transformation into Yogurt

    Directory of Open Access Journals (Sweden)

    Cornelia Vintila

    2011-10-01

    Full Text Available The purpose of our work was to evaluate in what measure milk urea concentration stays in processed yogurt and in what measure urea dose influences its quality. We added known amounts of urea into milk destined to yogurt processing in order to obtain probes with concentrations from 0,5 to 28 mg/ 100 ml milk. Obtained results lead us to the conclusion that milk urea decreases dramatically until the finishing of the process of milk coagulation and its transformation into yogurt. All probes which contained higher amounts of urea than 6 mg/ 100 ml milk, urea totally disappeared from yogurt before 48 hours of keeping. Milk coagulation time and its transformation to yogurt is reduced proportional with urea concentration in milk.

  11. Urea for long-term treatment of syndrome of inappropriate secretion of antidiuretic hormone.

    Science.gov (United States)

    Decaux, G; Genette, F

    1981-10-24

    The efficacy of oral urea in producing a sufficiently high osmotic diuresis was tested in seven patients with the syndrome of inappropriate secretion of antidiuretic hormone. In all patients urea corrected the hyponatraemia despite a normal fluid intake. Five patients were controlled (serum sodium concentration greater than 128 mmol(mEq)/1) with a dose of 30 g urea daily, and two with 60 g daily. The patients who needed 30 g drank 1-2 1 of fluid daily, while those who needed 60 g drank up to 3.1 per day. No major side effects were noted, even after treatment periods of up to 270 days. These findings suggest that urea is a safe and efficacious treatment of the syndrome of inappropriate secretion of antidiuretic hormone.

  12. Imposed Work of Breathing and Breathing Comfort of Nonintubated Volunteers Breathing with Three Portable Ventilators and a Critical Care Ventilator

    National Research Council Canada - National Science Library

    Austin, Paul

    2001-01-01

    .... The purpose of this study was to assess the imposed inspiratory work of breathing and breathing comfort of nonintubated healthy volunteers breathing spontaneously through three portable ventilators...

  13. Breathing Air Purification for Hyperbaric Purposes, Part II

    Directory of Open Access Journals (Sweden)

    Woźniak Arkadiusz

    2015-03-01

    Full Text Available Determining the efficiency of breathing air purification for hyperbaric purposes with the use of filtration systems is of a crucial importance. However, when the Polish Navy took samples of breathing air from their own filtration plant for quality purposes, these were found to not meet the required standard. The identification of this problem imposed the need to undertake actions aimed at the elimination of the identified disruptions in the process of breathing air production, with the objective of assuring its proper quality. This study presents the results of the initial tests on the air supply sources utilised by the Polish Navy, which were carried out for the purpose of setting a proper direction of future works and implementing corrective measures in order to optimise the breathing air production process. The obtained test results will be used in a subsequent publication devoted to the assessment of the level of efficiency of air purification with the use of a multifaceted approach consisting in the utilisation of various types of air supply sources and different configurations of purification systems.

  14. BREATHING EXERCISE RELAXATION INCREASE PHSYCOLOGICAL RESPONSE PRESCHOOL CHILDREN

    Directory of Open Access Journals (Sweden)

    Yuni Sufyanti Arief

    2017-07-01

    Full Text Available Introduction: Being hospitalize will be made the children become stress. Hospitalization response of the child particularly is afraid sense regard to painfull procedure and increase to attack the invasive procedure. The aimed of this study was to describe the influence of breathing exercise relaxation technique regarded to phsycological receiving responses in the preeliminary school chidren while they were receiving invasive procedure. Method: A quasy experimental purposive sampling design was used in this study. There were 20 respondents who met to the inclusion criteria. The independent variable was the breathing exercise relaxation technique and the dependent variable was phsycological receiving responses. Data for phsylogical response were collected by using observation form then analyzed by using Wilcoxon Signed Rank Test and Mann Whitney U Test with significance level α≤0.05. Result :  The result showed that breathing exercise relaxation technique had significance influence to phsycological response (p=0.000. Discussion: It,s can be concluded that breathing exercise relaxation technique has an effect to increase pshycological response in preeliminary school children who received invasive procedure.

  15. Treating agent for urea containing radioactive materials

    International Nuclear Information System (INIS)

    Ogawa, Hiroshi; Maki, Kentaro.

    1973-01-01

    Object: To add a coagulant into urea containing radioactive material to precipitate and remove the radioactive material in the urea. Structure: Iodosalt is added into urea and next, a mixed reagent in which silver ion or silver acetic ion and iron hydroxide precipitation or ferrite ion coexist is added therein. The urea is treated to have a sufficient alkaline, after which it is introduced into a basket type centrifuge formed with a filter layer in combination of an upper glass fiber layer and a lower active carbon layer. The treating agent can uniformly remove radioactive ion and radioactive chelate within urea containing inorganic salt and various metabolites. (Nakamura, S.)

  16. Carcass and meat traits, and non-carcass components of lambs fed ration containing increasing levels of urea

    Directory of Open Access Journals (Sweden)

    Sandra Rozanski

    2017-06-01

    Full Text Available The objective of this study was to evaluate the carcass and meat traits, and the non-carcass components of crossbred Dorper lambs fed diets with increasing levels of urea (0.0, 0.5, 1.0, and 1.5% of dry matter – DM. The experimental design was completely randomized with four treatments (urea inclusion levels and six replicates per treatment. Lambs were fed ad libitum for 56 days and slaughtered at 37.9 ± 5.1 kg of body weight (BW. The weight and yield of carcass before and after cooling were not influenced by urea levels, with average values of 16.9 kg and 44.6% for cold carcass weight and yield. Urea levels did not affect the morphometric measurements, the fat deposition on the carcass, the weight of carcass cuts and the weight of non-carcass components. There was a quadratic effect of urea levels on the loin yield, which may achieve maximum value of 11.31% with the inclusion of 0.84% DM urea in the feed. The pH and the color coordinates L* (brightness, a* (red intensity and C* (saturation of the meat also showed quadratic response to the urea levels, where in the minimum value of 5.53 for pH, maximum value of 48.67 for L* and minimum values of 14.04 and 16.21 for a* and C* may be obtained by including 0.53 to 0.70% DM urea in the ration. The inclusion of 0.84% DM urea in the ration is recommended to obtain maximum yield of loin and meat with attractive characteristics to the consumer, which is characterized by high red intensity and brightness. If consumers have preference for lamb meat with a more intense red color, the inclusion of 1.5% DM urea should be considered in the ration formulation.

  17. Serosal-to-mucosal urea flux across the isolated ruminal epithelium is mediated via urea transporter-B and aquaporins when Holstein calves are abruptly changed to a moderately fermentable diet.

    Science.gov (United States)

    Walpole, M E; Schurmann, B L; Górka, P; Penner, G B; Loewen, M E; Mutsvangwa, T

    2015-02-01

    Urea transport (UT-B) proteins are known to facilitate urea movement across the ruminal epithelium; however, other mechanisms may be involved as well because inhibiting UT-B does not completely abolish urea transport. Of the aquaporins (AQP), which are a family of membrane-spanning proteins that are predominantly involved in the movement of water, AQP-3, AQP-7, and AQP-10 are also permeable to urea, but it is not clear if they contribute to urea transport across the ruminal epithelium. The objectives of this study were to determine (1) the functional roles of AQP and UT-B in the serosal-to-mucosal urea flux (Jsm-urea) across rumen epithelium; and (2) whether functional adaptation occurs in response to increased diet fermentability. Twenty-five Holstein steer calves (n=5) were assigned to a control diet (CON; 91.5% hay and 8.5% vitamin and mineral supplement) or a medium grain diet (MGD; 41.5% barley grain, 50% hay, and 8.5% vitamin and mineral) that was fed for 3, 7, 14, or 21 d. Calves were killed and ruminal epithelium was collected for mounting in Ussing chambers under short-circuit conditions and for analysis of mRNA abundance of UT-B and AQP-3, AQP-7, and AQP-10. To mimic physiologic conditions, the mucosal buffer (pH 6.2) contained no urea, whereas the serosal buffer (pH 7.4) contained 1 mM urea. The fluxes of (14)C-urea (Jsm-urea; 26 kBq/10 mL) and (3)H-mannitol (Jsm-mannitol; 37 kBq/10 mL) were measured, with Jsm-mannitol being used as an indicator of paracellular or hydrophilic movement. Serosal addition of phloretin (1 mM) was used to inhibit UT-B-mediated urea transport, whereas NiCl2 (1 mM) was used to inhibit AQP-mediated urea transport. Across treatments, the addition of phloretin or NiCl2 reduced the Jsm-urea from 116.5 to 54.0 and 89.5 nmol/(cm(2) × h), respectively. When both inhibitors were added simultaneously, Jsm-urea was further reduced to 36.8 nmol/(cm(2) × h). Phloretin-sensitive and NiCl2-sensitive Jsm-urea were not affected by diet. The

  18. The effect of saturation magnetization of nanocatalyst and oscillating magnetic field for green urea synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Yahya, Noorhana, E-mail: noorhana_yahya@petronas.com.my; Alqasem, Bilal, E-mail: bilalalqasem@yahoo.com; Irfan, Muhammad; Qureshi, Saima; Rehman, Zia Ur; Shafie, Afza; Soleimani, Hassan

    2017-02-15

    Hematite and cupric oxide nanowires have been synthesized using the oxidation method for green urea production. Hematite nanowires were obtained by the oxidation of an iron wire at a temperature of 650 °C and ambient pressure in the presence of N{sub 2} and O{sub 2} gases. Cupric oxide nanowires were obtained by the same method at 700 °C, using a copper wire. The X-ray diffraction results show the formation of rhombohedral structure of α-Fe{sub 2}O{sub 3} and monoclinic phase of CuO. FE-SEM results reveal the formation of nanowires with dimensions ranging between 5–15 µm and 4–12 µm in length and a diametere ranging between 50–150 nm and 50–250 nm for α-Fe{sub 2}O{sub 3} and CuO respectively. The VSM results show that the saturation magnetization values for hematite and cupric oxide were 132.8700 and 0.0124 emu/g, respectively. The nanowires were used as catalyst for green urea synthesis in the presence of an oscillating and a static magnetic fields. The use of nanocatalyst with high saturation magnetization gives a higher yield of urea due to the increase in the singlet to triplet conversion. The highest yield of urea 11243 ppm was achieved by applying an oscillating magnetic field of frequency 0.5 MHz and using α-Fe{sub 2}O{sub 3} nanowires as nanocatalyst. - Highlights: • Effect of saturation magnetization of nanocatalyst on urea yield was investigated • Using nanocatalyst with high saturation magnetization value improved urea yield. • Effect of oscillating magnetic field frequency on the urea yield was investigated. • The highest urea yield was achieved by applying 0.5 MHz oscillating magnetic field.

  19. The effect of saturation magnetization of nanocatalyst and oscillating magnetic field for green urea synthesis

    International Nuclear Information System (INIS)

    Yahya, Noorhana; Alqasem, Bilal; Irfan, Muhammad; Qureshi, Saima; Rehman, Zia Ur; Shafie, Afza; Soleimani, Hassan

    2017-01-01

    Hematite and cupric oxide nanowires have been synthesized using the oxidation method for green urea production. Hematite nanowires were obtained by the oxidation of an iron wire at a temperature of 650 °C and ambient pressure in the presence of N 2 and O 2 gases. Cupric oxide nanowires were obtained by the same method at 700 °C, using a copper wire. The X-ray diffraction results show the formation of rhombohedral structure of α-Fe 2 O 3 and monoclinic phase of CuO. FE-SEM results reveal the formation of nanowires with dimensions ranging between 5–15 µm and 4–12 µm in length and a diametere ranging between 50–150 nm and 50–250 nm for α-Fe 2 O 3 and CuO respectively. The VSM results show that the saturation magnetization values for hematite and cupric oxide were 132.8700 and 0.0124 emu/g, respectively. The nanowires were used as catalyst for green urea synthesis in the presence of an oscillating and a static magnetic fields. The use of nanocatalyst with high saturation magnetization gives a higher yield of urea due to the increase in the singlet to triplet conversion. The highest yield of urea 11243 ppm was achieved by applying an oscillating magnetic field of frequency 0.5 MHz and using α-Fe 2 O 3 nanowires as nanocatalyst. - Highlights: • Effect of saturation magnetization of nanocatalyst on urea yield was investigated • Using nanocatalyst with high saturation magnetization value improved urea yield. • Effect of oscillating magnetic field frequency on the urea yield was investigated. • The highest urea yield was achieved by applying 0.5 MHz oscillating magnetic field.

  20. Serratia ureilytica sp. nov., a novel urea-utilizing species.

    Science.gov (United States)

    Bhadra, Bhaskar; Roy, Pradosh; Chakraborty, Ranadhir

    2005-09-01

    A Gram-negative, rod-shaped, urea-dissolving and non-spore-forming bacterium, designated strain NiVa 51(T), was isolated from water of the River Torsa in Hasimara, Jalpaiguri district, West Bengal, India. On the basis of 16S rRNA gene sequence similarity, strain NiVa 51(T) was shown to belong to the gamma-Proteobacteria and to be related to Serratia marcescens subsp. sakuensis (98.35%) and S. marcescens subsp. marcescens (98.30%); however, strain NiVa 51(T) exhibited only 43.7% similarity to S. marcescens by DNA-DNA hybridization. The G+C content of the genomic DNA of the isolate was 60 mol%. Both biochemical characteristics and fatty acid analysis data supported the affiliation of strain NiVa 51(T) to the genus Serratia. Furthermore, strain NiVa 51(T) was found to utilize urea as nitrogen source. The results of DNA-DNA hybridization as well as physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain NiVa 51(T) from recognized Serratia species. Strain NiVa 51(T) therefore represents a novel species, for which the name Serratia ureilytica sp. nov. is proposed, with type strain NiVa 51(T) (=LMG 22860(T)=CCUG 50595(T)).

  1. National Urea Cycle Disorders Foundation

    Science.gov (United States)

    ... urea cycle disorders. Donate Now To End Urea Cycle Disorders © 2005-2017 NUCDF. All rights reserved. This site may be freely linked to but not copied or duplicated in any fashion without the Foundation's consent. Make A Donation in ...

  2. 15N-urea tracing emission spectroscopy for detecting the infection of Helicobacter pylori

    International Nuclear Information System (INIS)

    Zhu Yayi

    2002-01-01

    Objective: To study a noninvasive and nonradioactive method, 15 N-urea tracing emission spectroscopy, for detecting the Helicobacter pylori (Hp) infection. Methods: A group of 26 patients was tested with a method of 15 N-urea tracing emission spectroscopy for detecting the Hp infection. Results: Taking the bacterial culture or (and) Gram stain as a standard, the specificity, sensitivity and positive predicting rate of the test were 81%, 89% and 84%, respectively. Conclusion: The method could be considered useful for clinical practice

  3. The effect of Helicobacter pylori eradication on macrophage migration inhibitory factor, C-reactive protein and fetuin-a levels

    Directory of Open Access Journals (Sweden)

    Levent Kebapcilar

    2010-06-01

    Full Text Available OBJECTIVES: To determine the effect of Helicobacter pylori (H. pylori eradication on blood levels of high-sensitivity C-reactive protein (hs-CRP, macrophage migration inhibitory factor and fetuin-A in patients with dyspepsia who are concurrently infected with H. pylori. METHODS: H.pylori infection was diagnosed based on the 14C urea breath test (UBT and histology. Lansoprazole 30 mg twice daily, amoxicillin 1 g twice daily, and clarithromycin 500 mg twice daily were given to all infected patients for 14 days; 14C UBT was then re-measured. In 30 subjects, migration inhibitory factor, fetuin-A and hs-CRP levels were examined before and after the eradication of H. pylori infection and compared to levels in 30 healthy subjects who tested negative for H. pylori infection. RESULTS: Age and sex distribution were comparable between patients and controls. Migration inhibitory factor and hs-CRP levels were higher, and fetuin-A levels were lower, in H. pylori-infected patients (p0.05. CONCLUSION: These findings suggest that H. pylori eradication reduces the levels of pro-inflammatory cytokines such as migration inhibitory factor and hs-CRP and also results in a significant increase in anti-inflammatory markers such as fetuin-A.

  4. Urea concentration in sheep’s milk

    Directory of Open Access Journals (Sweden)

    Jasmina Havranek

    2009-03-01

    Full Text Available Determining urea concentration in milk is a useful indicator for controlling supply of proteins to organisms, as well as the relationship of energy and protein in the food, thus it is finding more and more ways of practical use. The concentration of urea in milk, along with the feeding process, is influenced by a number of other factors such as: breed, stage and sequence of lactation, body mass, daily production and chemical structure of milk, number of somatic cells, season, milking.The goal of the research was to establish the influence of the breed (Island of Krk, East Frisian, lactation stage (beginning, middle and the end and the herd (3 to the concentration of urea in milk during lactation.For each breed there has been established daily quantity of milk, protein share and the concentration of urea in milk.Statistical analysis of data was conducted by using General Linear Models procedure, SAS program system (1999.The breed of sheep considerably (P<0.001 influenced daily quantity of milk, protein share and the concentration of urea in the milk.East Frisian sheep produced on average almost double the daily quantities of milk (1070 mL compared to the Krk sheep (588 mL.Protein share and the urea concentration in Krk sheep milk were higher (5.99 % and 35.97 mg/100 mL then in the milk of East Frisian sheep (5.12 % and 33.31 mg/100 mL.For both breeds the significant influence of lactation stage to the daily milk quantity has been established (0.001, that is also for the urea concentration in the milk of Krk sheep (0.001, as well as protein share in the milk of East Frisian sheep (0.001.Herd influence significantly affected daily milk quantities (0.001 and concentration of urea in the milk (0.05.The defining of the urea concentration in sheep milk should be occasionally carried out in the Republic of Croatia to establish the standard physiological values typical for the particular sheep breed.

  5. Nicotine, acetanilide and urea multi-level2H-,13C- and15N-abundance reference materials for continuous-flow isotope ratio mass spectrometry

    Science.gov (United States)

    Schimmelmann, A.; Albertino, A.; Sauer, P.E.; Qi, H.; Molinie, R.; Mesnard, F.

    2009-01-01

    Accurate determinations of stable isotope ratios require a calibration using at least two reference materials with different isotopic compositions to anchor the isotopic scale and compensate for differences in machine slope. Ideally, the S values of these reference materials should bracket the isotopic range of samples with unknown S values. While the practice of analyzing two isotopically distinct reference materials is common for water (VSMOW-SLAP) and carbonates (NBS 19 and L-SVEC), the lack of widely available organic reference materials with distinct isotopic composition has hindered the practice when analyzing organic materials by elemental analysis/isotope ratio mass spectrometry (EA-IRMS). At present only L-glutamic acids USGS40 and USGS41 satisfy these requirements for ??13C and ??13N, with the limitation that L-glutamic acid is not suitable for analysis by gas chromatography (GC). We describe the development and quality testing of (i) four nicotine laboratory reference materials for on-line (i.e. continuous flow) hydrogen reductive gas chromatography-isotope ratio mass-spectrometry (GC-IRMS), (ii) five nicotines for oxidative C, N gas chromatography-combustion-isotope ratio mass-spectrometry (GC-C-IRMS, or GC-IRMS), and (iii) also three acetanilide and three urea reference materials for on-line oxidative EA-IRMS for C and N. Isotopic off-line calibration against international stable isotope measurement standards at Indiana University adhered to the 'principle of identical treatment'. The new reference materials cover the following isotopic ranges: ??2Hnicotine -162 to -45%o, ??13Cnicotine -30.05 to +7.72%, ?? 15Nnicotine -6.03 to +33.62%; ??15N acetanilide +1-18 to +40.57%; ??13Curea -34.13 to +11.71%, ??15Nurea +0.26 to +40.61% (recommended ?? values refer to calibration with NBS 19, L-SVEC, IAEA-N-1, and IAEA-N-2). Nicotines fill a gap as the first organic nitrogen stable isotope reference materials for GC-IRMS that are available with different ??13N

  6. A study of the effects of oral contraceptives on plasma urea of Wistar ...

    African Journals Online (AJOL)

    Oral contraceptives such as Microgynon a combined pill (0.15mg levonorgestrel and 0.03mg ethinylestradiol) and Primolut -N a mini pill (5mg norethisterone) were investigated for their in-vivo effects on wistar albino rat rattus rattus plasma urea levels. Test results showed that the drugs had a lowering effect on plasma urea ...

  7. 40 CFR 721.9925 - Aminoethylethylene urea methacrylamide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aminoethylethylene urea methacrylamide... Substances § 721.9925 Aminoethylethylene urea methacrylamide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an aminoethylethylene urea...

  8. Reverse iontophoresis of urea in health and chronic kidney disease: a potential diagnostic and monitoring tool?

    Science.gov (United States)

    Ebah, Leonard M; Read, Ian; Sayce, Andrew; Morgan, Jane; Chaloner, Christopher; Brenchley, Paul; Mitra, Sandip

    2012-01-01

    Background Patients with chronic kidney disease (CKD) need regular monitoring, usually by blood urea and creatinine measurements, needing venepuncture, frequent attendances and a healthcare professional, with significant inconvenience. Noninvasive monitoring will potentially simplify and improve monitoring. We tested the potential of transdermal reverse iontophoresis of urea in patients with CKD and healthy controls. Methods Using a MIC 2® Iontophoresis Controller, reverse iontophoresis was applied on the forearm of five healthy subjects (controls) and 18 patients with CKD for 3–5 h. Urea extracted at the cathode was measured and compared with plasma urea. Results Reverse iontophoresis at 250 μA was entirely safe for the duration. Cathodal buffer urea linearly correlated with plasma urea after 2 h (r = 0·82, P urea (y) from cathodal urea after 2 and 3 h, respectively. Cathodal urea concentration in controls was significantly lower than in patients with CKD after a minimum current application of 2 h (P urea cut-off of 30 μM gave a sensitivity of 83·3% and positive predictive value of 87% CKD. During haemodialysis, the fall in cathodal urea was able to track that of blood urea. Conclusion Reverse iontophoresis is safe, can potentially discriminate patients with CKD and healthy subjects and is able to track blood urea changes on dialysis. Further development of the technology for routine use can lead to an exciting opportunity for its use in diagnostics and monitoring. PMID:22409780

  9. Breathing is different in the quantum world

    Science.gov (United States)

    Bonitz, Michael; Bauch, Sebastian; Balzer, Karsten; Henning, Christian; Hochstuhl, David

    2009-11-01

    Interacting classicle particles in a harmonic trap are known to possess a radial collective oscillation -- the breathing mode (BM). In case of Coulomb interaction its frequency is universal -- it is independent of the particle number and system dimensionality [1]. Here we study strongly correlated quantum systems. We report a qualitatively different breathing behavior: a quantum system has two BMs one of which is universal whereas the frequency of the other varies with system dimensionality, the particle spin and the strength of the pair interaction. The results are based on exact solutions of the time-dependent Schr"odinger equation for two particles and on time-dependent many-body results for larger particle numbers. Finally, we discuss experimental ways to excite and measure the breathing frequencies which should give direct access to key properties of trapped particles, including their many-body effects [2]. [4pt] [1] C. Henning et al., Phys. Rev. Lett. 101, 045002 (2008) [0pt] [2] S. Bauch, K. Balzer, C. Henning, and M. Bonitz, submitted to Phys. Rev. Lett., arXiv:0903.1993

  10. Effect of urea and urea-gamma treatments on cellulose degradation of Thai rice straw and corn stalk

    International Nuclear Information System (INIS)

    Banchorndhevakul, Siriwattana

    2002-01-01

    Cellulose degradation of 20% urea treated and 20% urea-10 kGy gamma treated Thai rice straw and corn stalk showed that combination effect of urea and gamma radiation gave a higher % decrease in neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), cellulose, hemicellulose, and lignin and cutin in comparison with urea effect only for both room temperature storage and room temperature +258 K storage. The results also indicated that cellulose degradation proceeded with time, even at 258 K. A drastic drop to less than half of the original contents in NDF, ADF, and ADL could not be obtained in this study

  11. Effect of urea and urea-gamma treatments on cellulose degradation of Thai rice straw and corn stalk

    Science.gov (United States)

    Banchorndhevakul, Siriwattana

    2002-08-01

    Cellulose degradation of 20% urea treated and 20% urea-10 kGy gamma treated Thai rice straw and corn stalk showed that combination effect of urea and gamma radiation gave a higher % decrease in neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), cellulose, hemicellulose, and lignin and cutin in comparison with urea effect only for both room temperature storage and room temperature +258 K storage. The results also indicated that cellulose degradation proceeded with time, even at 258 K. A drastic drop to less than half of the original contents in NDF, ADF, and ADL could not be obtained in this study.

  12. Comparison of breath testing with fructose and high fructose corn syrups in health and IBS.

    Science.gov (United States)

    Skoog, S M; Bharucha, A E; Zinsmeister, A R

    2008-05-01

    Although incomplete fructose absorption has been implicated to cause gastrointestinal symptoms, foods containing high fructose corn syrup (HFCS) contain glucose. Glucose increases fructose absorption in healthy subjects. Our hypothesis was that fructose intolerance is less prevalent after HFCS consumption compared to fructose alone in healthy subjects and irritable bowel syndrome (IBS). Breath hydrogen levels and gastrointestinal symptoms were assessed after 40 g of fructose (12% solution) prepared either in water or as HFCS, administered in double-blind randomized order on 2 days in 20 healthy subjects and 30 patients with IBS. Gastrointestinal symptoms were recorded on 100-mm Visual Analogue Scales. Breath hydrogen excretion was more frequently abnormal (P fructose (68%) than HFCS (26%) in controls and patients. Fructose intolerance (i.e. abnormal breath test and symptoms) was more prevalent after fructose than HFCS in healthy subjects (25% vs. 0%, P = 0.002) and patients (40% vs. 7%, P = 0.062). Scores for several symptoms (e.g. bloating r = 0.35) were correlated (P fructose but not HFCS; in the fructose group, this association did not differ between healthy subjects and patients. Symptoms were not significantly different after fructose compared to HFCS. Fructose intolerance is more prevalent with fructose alone than with HFCS in health and in IBS. The prevalence of fructose intolerance is not significantly different between health and IBS. Current methods for identifying fructose intolerance should be modified to more closely reproduce fructose ingestion in daily life.

  13. Porous Cross-Linked Polyimide-Urea Networks

    Science.gov (United States)

    Meador, Mary Ann B. (Inventor); Nguyen, Baochau N. (Inventor)

    2015-01-01

    Porous cross-linked polyimide-urea networks are provided. The networks comprise a subunit comprising two anhydride end-capped polyamic acid oligomers in direct connection via a urea linkage. The oligomers (a) each comprise a repeating unit of a dianhydride and a diamine and a terminal anhydride group and (b) are formulated with 2 to 15 of the repeating units. The subunit was formed by reaction of the diamine and a diisocyanate to form a diamine-urea linkage-diamine group, followed by reaction of the diamine-urea linkage-diamine group with the dianhydride and the diamine to form the subunit. The subunit has been cross-linked via a cross-linking agent, comprising three or more amine groups, at a balanced stoichiometry of the amine groups to the terminal anhydride groups. The subunit has been chemically imidized to yield the porous cross-linked polyimide-urea network. Also provided are wet gels, aerogels, and thin films comprising the networks, and methods of making the networks.

  14. Development of an Optical Urea Biosensor Using Polypyrrole-polyvinyl Sulphonate Film

    Directory of Open Access Journals (Sweden)

    H. J. KHARAT

    2009-02-01

    Full Text Available Development of an intensity modulated fiber optic PPy-PVS biosensor for the detection of urea has been presented. The sensor design is based on the modified cladding technique. Polypyrrole (PPy film doped with polyvinyl sulfonate (PVS was synthesized (by in-situ chemical polymerization at room temperature with optimized process parameters. The PPy-PVS film provides good porous matrix for the immobilization of enzyme-urease on the sensing probe by cross linking via glutaraldehyde. The characterization of the urea biosensor has been carried out with an indigenously developed sensing chamber and optical fiber test bench. This biosensor showed almost stable and linear response to urea in the range 1-100 mM up to 24 days. It shows very good selectivity and repeatability.

  15. Mapleson′s breathing systems

    Directory of Open Access Journals (Sweden)

    Tej K Kaul

    2013-01-01

    Full Text Available Mapleson breathing systems are used for delivering oxygen and anaesthetic agents and to eliminate carbon dioxide during anaesthesia. They consist of different components: Fresh gas flow, reservoir bag, breathing tubes, expiratory valve, and patient connection. There are five basic types of Mapleson system: A, B, C, D and E depending upon the different arrangements of these components. Mapleson F was added later. For adults, Mapleson A is the circuit of choice for spontaneous respiration where as Mapleson D and its Bains modifications are best available circuits for controlled ventilation. For neonates and paediatric patients Mapleson E and F (Jackson Rees modification are the best circuits. In this review article, we will discuss the structure of the circuits and functional analysis of various types of Mapleson systems and their advantages and disadvantages.

  16. Foliar fertilization of sugarcane (Saccharum spp): absorption and translocation of 15-N-labeled urea

    International Nuclear Information System (INIS)

    Trivelin, P.C.O.; Carvalho, J.G. de; Silva, A.Q. da; Primavesi, A.C.P.A.; Camacho, E.; Eimori, I.E.; Guilherme, M.R.

    1988-01-01

    The absorption and translocation of foliar applied nitrogen as urea solution to sugar cane plants was evaluated. An experiment using the isotope dilution technique with 15 N labeled urea was carried out in green house condition. Seedlings of sugarcane variety IAC 53-150 were planted in pots with 5KG of top soil''latossolo vermelho amarelo, fase arenosa'' (Haplustox). (M.A.C.) [pt

  17. Application of lime and urea and its effect on development of Phythophthora palmivora.

    Directory of Open Access Journals (Sweden)

    Sakti Widyanta Pratama

    2015-03-01

    Full Text Available Black pod rot disease (BPRD which is caused by Phytophthora palmivora is one of the main diseases of cocoa cultivations particularly in plantations with wet climate. Black pod rot can develop rapidly under high humidity environments, particularly during rainy seasons. This disease can cause loss of harvest of up to 46.63% in East Java. The various control efforts attempted so far have not resulted in significant improvements. Urea, in addition to functioning as fertilizer, can also produce the ammonia gas which is believed to be able to suppress black pod rot. This research aims to determine the effectiveness of black pod rot control using the combination of lime and urea. This research was conducted from June to September 2013. The materials used in test included sterile soil, black pod rot infected cocoa, urea, and agricultural lime. Observation results showed that ammonia could form from urea. Lime can increase the speed of the formation. The ammonia gas forming from 0.06% urea and 0.3% lime can control the P. palmivora fungus inside the soil. Key words: Pod rot, P. palmivora, urea, lime, ammonia

  18. Structural properties and adsorption capacity of holocellulose aerogels synthesized from an alkali hydroxide-urea solution

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Gu-Joong; Kim, Dae-Young; Hwang, Jae-Hyun; Kang, Joo-Hyon [Dongguk University, Seoul (Korea, Republic of)

    2014-05-15

    A tulip tree was used to synthesize a holocellulose aerogel from an aqueous alkali hydroxide-urea solution with the substitution of an organic solvent followed by freeze-drying. For comparison, the synthesized holocellulose aerogels were divided into two groups according to the source of the hydrogel, an upper suspended layer and a bottom concentrated layer of the centrifuged solution of cellulose and NaOH/urea solvents. We investigated the effects of the temperature of the pre-cooled NaOH/urea solution (i.e., dissolution temperature) on the pore structure and the adsorption capacity of the holocellulose aerogel. A nano-fibrillar network structure of the holocellulose aerogel was observed, with little morphological difference in pore structure for different dissolution temperatures. Both micropores and mesopores were observed in the holocellulose aerogel. The specific surface area of the holocellulose aerogel was generally greater at lower dissolution temperatures. In a series of adsorption tests using methylene blue, the holocellulose aerogel showed the greatest adsorption capacity at the lowest dissolution temperature tested ( -2 .deg. C). However, the dissolution temperature generally had little effect on the adsorption capacity. The holocellulose aerogel produced from the upper suspended layer of the centrifuged hydrogel solution showed a greater porosity and adsorption capacity than the one produced from the bottom concentrated layer. Overall, the aerogel made by utilizing a delignified tulip tree display a high surface area and a high adsorption property, indicating its possible application in eco-friendly adsorption materials.

  19. Structural properties and adsorption capacity of holocellulose aerogels synthesized from an alkali hydroxide-urea solution

    International Nuclear Information System (INIS)

    Kwon, Gu-Joong; Kim, Dae-Young; Hwang, Jae-Hyun; Kang, Joo-Hyon

    2014-01-01

    A tulip tree was used to synthesize a holocellulose aerogel from an aqueous alkali hydroxide-urea solution with the substitution of an organic solvent followed by freeze-drying. For comparison, the synthesized holocellulose aerogels were divided into two groups according to the source of the hydrogel, an upper suspended layer and a bottom concentrated layer of the centrifuged solution of cellulose and NaOH/urea solvents. We investigated the effects of the temperature of the pre-cooled NaOH/urea solution (i.e., dissolution temperature) on the pore structure and the adsorption capacity of the holocellulose aerogel. A nano-fibrillar network structure of the holocellulose aerogel was observed, with little morphological difference in pore structure for different dissolution temperatures. Both micropores and mesopores were observed in the holocellulose aerogel. The specific surface area of the holocellulose aerogel was generally greater at lower dissolution temperatures. In a series of adsorption tests using methylene blue, the holocellulose aerogel showed the greatest adsorption capacity at the lowest dissolution temperature tested ( -2 .deg. C). However, the dissolution temperature generally had little effect on the adsorption capacity. The holocellulose aerogel produced from the upper suspended layer of the centrifuged hydrogel solution showed a greater porosity and adsorption capacity than the one produced from the bottom concentrated layer. Overall, the aerogel made by utilizing a delignified tulip tree display a high surface area and a high adsorption property, indicating its possible application in eco-friendly adsorption materials.

  20. Na,K-ATPase structure/function relationships probed by the denaturant urea.

    Science.gov (United States)

    Esmann, Mikael; Fedosova, Natalya U; Olesen, Claus

    2015-05-01

    Urea interacts with the Na,K-ATPase, leading to reversible as well as irreversible inhibition of the hydrolytic activity. The enzyme purified from shark rectal glands is more sensitive to urea than Na,K-ATPase purified from pig kidney. An immediate and reversible inhibition under steady-state conditions of hydrolytic activity at 37°C is demonstrated for the three reactions studied: the overall Na,K-ATPase activity, the Na-ATPase activity observed in the absence of K+ as well as the K+-dependent phosphatase reaction (K-pNPPase) seen in the absence of Na+. Half-maximal inhibition is seen with about 1M urea for shark enzyme and about 2M urea for pig enzyme. In the presence of substrates there is also an irreversible inhibition in addition to the reversible process, and we show that ATP protects against the irreversible inhibition for both the Na,K-ATPase and Na-ATPase reaction, whereas the substrate paranitrophenylphosphate leads to a slight increase in the rate of irreversible inhibition of the K-pNPPase. The rate of the irreversible inactivation in the absence of substrates is much more rapid for shark enzyme than for pig enzyme. The larger number of potentially urea-sensitive hydrogen bonds in shark enzyme compared to pig enzyme suggests that interference with the extensive hydrogen bonding network might account for the higher urea sensitivity of shark enzyme. The reversible inactivation is interpreted in terms of domain interactions and domain accessibilities using as templates the available crystal structures of Na,K-ATPase. It is suggested that a few interdomain hydrogen bonds are those mainly affected by urea during reversible inactivation. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Tailoring of analytical performances of urea biosensors using nanomaterials

    International Nuclear Information System (INIS)

    Nouira, W; Barhoumi, H; Maaref, A; Renault, N Jaffrézic; Siadat, M

    2013-01-01

    This paper is a contribution to the study of enzymatic sensors based on nanoparticles of iron oxide (FeNPs). Urease enzyme was immobilized on FeNPs using layer-by-layer (LbL) deposition method. FeNPs were first coated with polyelectrolytes (PE): Poly (allylamine hydrochloride), PAH and Poly (sodium 4-styrenesulfonate), PSS for enzyme immobilization and then with enzyme. It has been confirmed through zeta potential measurements of FeNPs that the enzyme is immobilized on the surface. We evaluated the sensitivity of biosensors for urea by potentiometric and capacitive measurements on silicon / silica / FeNP-LBL-urease structures. The recorded capacity-potential curves (C-V) show a significant shift of flat band potential towards negative potentials in the presence of urea, the observed values of sensitivity vary between 30 and 40 mV/p[urea]. It has been shown that the proposed method for the immobilization of urease can increase the dynamic range of urea detection (10 −4 M to 10 −1 M) compared to the immobilization of urease without FeNP (10 −3.5 M to 10 −2.5 M). When the number of PAH-PSS layers was increased the sensitivity of detection was modified. This effect is due to partial inhibition of the enzyme in presence of FeNPs, which was shown by measurements in homogeneous phase.

  2. Role of measurement of cystatin C in analyzing the results of renal function tests in patients with essential hypertension

    International Nuclear Information System (INIS)

    Zhang Xiaofeng; Lu Hongtai; Dong Yaorong; Xia Jing; Liu Yi

    2003-01-01

    Objective: To explore the use of cystatin C for analysing the results of renal function tests and renal blood flow study in patients with essential hypertension. Methods: The following tests were performed in 62 patients with essential hypertension and 32 controls: plasma cystatin C (with LPET), plasma ET (with RIA), four urinary sensitive parameters for detecting early renal injury i.e. urinary Alb/Cr, NAG/Cr and α-mG/Cr (with ELISA) and renal blood flow study (with Doppler). Results: The patients could be divided into two groups: Cystatin C positive (above normal value, n=23) and cystamin C negative (n=39). Plasma ET levels in cystamin C positive group were significantly higher than those in the 32 controls. Values of the four urinary parameters in the two patient groups were very significantly higher than those in the controls (p<0.01), the difference between the two patient groups was also very significant (p<0.01). Renal arterial blood flow in the two patient groups was much different from that was no significant difference between the two groups themselves. In the patients, with the decrease of GFR, Serum creatinine levels were elevated but urea nitrogen levels remained within normal limit. Conclusion: In the cystamin C negative patients, there was already marked alteration of the renal blood flow through auto-regulation. Although GFR, serum creatinine and urea nitrogen levels remained within normal range, early renal injury, especially tubular ones had been present. As the disease worsened and cystatin levels increased, there was no progressive alteration of renal blood flow. Marked deterioration of renal glomeruli and tubular functions could be detected

  3. Role of measurement of cystatin C in analyzing the results of renal function tests in patients with essential hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Xiaofeng, Zhang; Hongtai, Lu; Yaorong, Dong; Jing, Xia; Yi, Liu [Chinese Traditional Medicine of Shanghai Hospital, Shanghai (China)

    2003-08-01

    Objective: To explore the use of cystatin C for analysing the results of renal function tests and renal blood flow study in patients with essential hypertension. Methods: The following tests were performed in 62 patients with essential hypertension and 32 controls: plasma cystatin C (with LPET), plasma ET (with RIA), four urinary sensitive parameters for detecting early renal injury i.e. urinary Alb/Cr, NAG/Cr and {alpha}-mG/Cr (with ELISA) and renal blood flow study (with Doppler). Results: The patients could be divided into two groups: Cystatin C positive (above normal value, n=23) and cystamin C negative (n=39). Plasma ET levels in cystamin C positive group were significantly higher than those in the 32 controls. Values of the four urinary parameters in the two patient groups were very significantly higher than those in the controls (p<0.01), the difference between the two patient groups was also very significant (p<0.01). Renal arterial blood flow in the two patient groups was much different from that was no significant difference between the two groups themselves. In the patients, with the decrease of GFR, Serum creatinine levels were elevated but urea nitrogen levels remained within normal limit. Conclusion: In the cystamin C negative patients, there was already marked alteration of the renal blood flow through auto-regulation. Although GFR, serum creatinine and urea nitrogen levels remained within normal range, early renal injury, especially tubular ones had been present. As the disease worsened and cystatin levels increased, there was no progressive alteration of renal blood flow. Marked deterioration of renal glomeruli and tubular functions could be detected.

  4. Patients' experiences of breathing retraining for asthma: a qualitative process analysis of participants in the intervention arms of the BREATHE trial.

    Science.gov (United States)

    Arden-Close, Emily; Yardley, Lucy; Kirby, Sarah; Thomas, Mike; Bruton, Anne

    2017-10-05

    , interviewed 16 people about their experiences in a trial that tested breathing retraining exercises delivered by DVD or face-to-face sessions with a respiratory physiotherapist. Overwhelmingly, trial participants reported that breathing retraining sessions gave them greater control over their symptoms, helped them relax, improved their quality of life and reduced the need for medications. Some participants who received DVD instruction said they had trouble mastering the techniques, and many in both groups found it hard to find time to practice the exercises. Overall, however, patients were positive about the experience. The authors conclude that breathing exercises are likely to be a well-received method of asthma management.

  5. Examination of breath alcohol concentration (BrAC) levels, alcohol use disorders identification test (AUDIT-C) classification, and intended plans for getting home among bar-attending college students.

    Science.gov (United States)

    Martin, Ryan J; Chaney, Beth H; Cremeens-Matthews, Jennifer

    2015-06-01

    The college student population is one of the heaviest drinking demographic groups in the US and impaired driving is a serious alcohol-related problem. The objective of this study is to better understand the relationship between alcohol-related behaviors and "plans to get home" among a sample of college students. We conducted four anonymous field studies to examine associations between breath alcohol concentration (BrAC) levels, Alcohol Use Disorders Identification Test (AUDIT-C) classification, and plans for getting home among a sample of bar-attending college students (N = 713). The vast majority of participants in our sample (approximately 95%) were not intending to drive and the average BrAC% of those intending to drive was .041. Our one-way ANOVAs indicated that (1) participants classified by the AUDIT-C as not having an alcohol problem had a significantly lower BrAC% than those classified as having a potential problem and (2) participants planning to drive had a significantly lower BrAC% than those with a plan that did not involve them driving and those without a plan to get home. Although it is encouraging that most of our sample was not intending to drive, it is important to continue to attempt to reduce impaired driving in this population. This study helps college health professionals and administrators to better understand the relationship between alcohol-related behaviors and plans to get home among college students. © American Academy of Addiction Psychiatry.

  6. Utilization of urea-nitrogen-15 in ruminants

    International Nuclear Information System (INIS)

    Boda, K.; Varady, J.; Havassy, I.

    1976-01-01

    In Merino sheep a series of experiments were carried out investigating exogenous and endogenous urea utilization. On the experimental sheep with isolated jejunum, rumen and intestine fistula, re-entral intestine cannulae, and after intra-ruminal or intra-intestinal 15 N-urea administration it was found that urea- 15 N takes part in the nitrogen recycling, and is utilized in the nitrogen pool. In experiments with synthetic protein-free diet, low protein diet and high nitrogen diet, after the intravenous administration of 15 N-urea the following findings were made: The results of experiments with synthetic diet, where the only nitrogen source was perorally (for 3-6 months) and then intravenously (for 3 months) administered urea, indicated the ability of ruminants to replace fully the nitrogen in the feed under certain conditions by increased endogenous urea recirculation. The results of the experiments with various nitrogen intakes showed that considerable amounts of urea- 15 N (44-96% from the given dose) were retained. Nitrogen compounds synthetized from blood urea- 15 N were recycled through the alimentary tract. Its secretion predominated in the forestomachs, abomasum and duodenum, and its reabsorption took place in the intestinal tract. From the 15 N incorporated into the nitrogenous substances which passed through the duodenum, 73-84% was reabsorbed. The retained 15 N was incorporated into the microbial and plasma proteins and its amide-N. On the basis of these results it is concluded that in addition to the rumeno-hepatal circulation, the entero-hepatal circulation of nitrogenous substances, including endogenous nitrogen, also plays an important role quantitatively and perhaps qualitatively in the process of re-utilizing the blood urea N for proteosynthesis and synthesis of other N-metabolites in ruminants. The hydrolysis of endogenous urea in the gastro-intestinal tract of ruminants and its utilization is a natural process indispensable for the maintenance of

  7. Urea-assisted low temperature green synthesis of graphene nanosheets for transparent conducting film

    Science.gov (United States)

    Chamoli, Pankaj; Das, Malay K.; Kar, Kamal K.

    2018-02-01

    Present work demonstrates the fabrication of graphene nanosheet (GN) based transparent conducting film (TCF) using spray coating. Green synthesis of GN is carried out by reduction of graphene oxide (GO) using urea as green reducing agent. The reductive ability of urea with varied concentration is studied for GO at low temperature (i.e., 90 °C). As synthesized graphene nanosheets (GNs) are characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-visible spectroscopy, field emission scanning electron microscopy (FESEM), atomic force microscope (AFM), and X-ray Photon spectroscopy (XPS). Raman analysis confirms that the maximum reduction of oxygen species is noticed using 30 mg/ml urea concentration at 90 °C from GO, and found Raman D to G band ratio (ID/IG) of ∼1.30. XPS analysis validates the Raman signature of removal of oxygen functional groups from GO, and obtained C/O ratio of ∼5.28. Further, transparent conducting films (TCFs) are fabricated using synthesized GNs. Thermal graphitization is carried out to enhance the optical and electrical properties of TCFs. TCF shows best performance when it is annealed at 900 °C for 1 h in vacuum, and obtained sheet resistance is ∼1.89 kΩ/□ with transmittance of ∼62.53%.

  8. Breath Tests Application in Order to Improve the Outcomes of Treatment for Celiac Disease

    Directory of Open Access Journals (Sweden)

    Ye.Yu. Gubskaya

    2014-02-01

    Full Text Available The article presents data from an own study on modern opportunities to improve the effectiveness of treatment of patients with celiac disease (n = 41. All patients were on a gluten-free diet, nonetheless effectiveness of treatment was regarded as unsatisfactory. Due to the use of modern carbon and hydrogen breath tests and diagnosis of bacterial overgrowth syndrome, lactase deficiency and exocrine pancreatic insufficiency, which were the causes for the persistence of clinical symptoms, we obtained reasons for their correction and achieved a complete remission of the underlying disease.

  9. Residual effect of sugar cane ratoon of urea nitrogen foliar application to plant cane

    International Nuclear Information System (INIS)

    Trivelin, P.C.O.; Lara Cabezas, W.A.R.; Coleti, J.T.

    1984-01-01

    The residual effect of urea - N, foliar applied to plant cane, on sugar cane ratoon is studied. Setts grown in drums containing washed sand are used. 180 days from planting, foliar fertilizer (43.5% urea solution) labelled with 3.95 atom % 15 N is applied. The first harvest is made 7 days after application and final harvest of resprouting at 123 days. (M.A.C.) [pt

  10. Urea impairs β cell glycolysis and insulin secretion in chronic kidney disease

    Science.gov (United States)

    Koppe, Laetitia; Nyam, Elsa; Vivot, Kevin; Manning Fox, Jocelyn E.; Dai, Xiao-Qing; Nguyen, Bich N.; Attané, Camille; Moullé, Valentine S.; MacDonald, Patrick E.; Ghislain, Julien

    2016-01-01

    Disorders of glucose homeostasis are common in chronic kidney disease (CKD) and are associated with increased mortality, but the mechanisms of impaired insulin secretion in this disease remain unclear. Here, we tested the hypothesis that defective insulin secretion in CKD is caused by a direct effect of urea on pancreatic β cells. In a murine model in which CKD is induced by 5/6 nephrectomy (CKD mice), we observed defects in glucose-stimulated insulin secretion in vivo and in isolated islets. Similarly, insulin secretion was impaired in normal mouse and human islets that were cultured with disease-relevant concentrations of urea and in islets from normal mice treated orally with urea for 3 weeks. In CKD mouse islets as well as urea-exposed normal islets, we observed an increase in oxidative stress and protein O-GlcNAcylation. Protein O-GlcNAcylation was also observed in pancreatic sections from CKD patients. Impairment of insulin secretion in both CKD mouse and urea-exposed islets was associated with reduced glucose utilization and activity of phosphofructokinase 1 (PFK-1), which could be reversed by inhibiting O-GlcNAcylation. Inhibition of O-GlcNAcylation also restored insulin secretion in both mouse models. These results suggest that insulin secretory defects associated with CKD arise from elevated circulating levels of urea that increase islet protein O-GlcNAcylation and impair glycolysis. PMID:27525435

  11. Spectroscopic and MD simulation studies on unfolding processes of mitochondrial carbonic anhydrase VA induced by urea.

    Science.gov (United States)

    Idrees, Danish; Prakash, Amresh; Haque, Md Anzarul; Islam, Asimul; Ahmad, Faizan; Hassan, Md Imtaiyaz

    2016-09-01

    Carbonic anhydrase VA (CAVA) is primarily expressed in the mitochondria and involved in numerous physiological processes including lipogenesis, insulin secretion from pancreatic cells, ureagenesis, gluconeogenesis and neuronal transmission. To understand the biophysical properties of CAVA, we carried out a reversible urea-induced isothermal denaturation at pH 7.0 and 25°C. Spectroscopic probes, [θ]222 (mean residue ellipticity at 222 nm), F344 (Trp-fluorescence emission intensity at 344 nm) and Δε280 (difference absorption at 280 nm) were used to monitor the effect of urea on the structure and stability of CAVA. The urea-induced reversible denaturation curves were used to estimate [Formula: see text], Gibbs free energy in the absence of urea; Cm, the mid-point of the denaturation curve, i.e. molar urea concentration ([urea]) at which ΔGD = 0; and m, the slope (=∂ΔGD/∂[urea]). Coincidence of normalized transition curves of all optical properties suggests that unfolding/refolding of CAVA is a two-state process. We further performed 40 ns molecular dynamics simulation of CAVA to see the dynamics at different urea concentrations. An excellent agreement was observed between in silico and in vitro studies.

  12. Urea, a true uremic toxin: the empire strikes back.

    Science.gov (United States)

    Lau, Wei Ling; Vaziri, Nosratola D

    2017-01-01

    Blood levels of urea rise with progressive decline in kidney function. Older studies examining acute urea infusion suggested that urea was well-tolerated at levels 8-10× above normal values. More recent in vitro and in vivo work argue the opposite and demonstrate both direct and indirect toxicities of urea, which probably promote the premature aging phenotype that is pervasive in chronic kidney disease (CKD). Elevated urea at concentrations typically encountered in uremic patients induces disintegration of the gut epithelial barrier, leading to translocation of bacterial toxins into the bloodstream and systemic inflammation. Urea induces apoptosis of vascular smooth muscle cells as well as endothelial dysfunction, thus directly promoting cardiovascular disease. Further, urea stimulates oxidative stress and dysfunction in adipocytes, leading to insulin resistance. Finally, there are widespread indirect effects of elevated urea as a result of the carbamylation reaction, where isocyanic acid (a product of urea catabolism) alters the structure and function of proteins in the body. Carbamylation has been linked with renal fibrosis, atherosclerosis and anaemia. In summary, urea is a re-emerging Dark Force in CKD pathophysiology. Trials examining low protein diet to minimize accumulation of urea and other toxins suggest a clinical benefit in terms of slowing progression of CKD. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  13. Variation of milk urea in dairy cattle : a study on factors that affect the relationship between urea concentration in milk and urea excretion in urine

    NARCIS (Netherlands)

    Spek, J.W.

    2013-01-01

    The aim of this thesis was to increase the applicability of milk urea nitrogen concentration (MUN) as a predictor of urinary urea nitrogen excretion (UUN) by identifying and quantifying factors that can explain variation in MUN that is not related to UUN. A literature study was conducted in

  14. Carcass characteristics of sheep fed diets with slow-release urea replacing conventional urea

    Directory of Open Access Journals (Sweden)

    Evanilton Moura Alves

    2014-07-01

    Full Text Available This study aimed to evaluate the effects of adding slow-release urea to replace conventional urea in the diet on carcass characteristics of feedlot sheep. We used 20 Santa Ines x SRD rams, with average body weight of 21.1±1.2 kgand average age of 120 days, distributed in a completely randomized design with 5 treatments. The replacement levels used as treatments were 0, 20, 40, 60, and 80%, composing diets of about 12% crude protein, with 50 % Tifton-85 hay and 50% concentrate. There was no influence of slow release urea on weight at slaughter (35.17 kg, and on hot (16.75 kg and cold (16.24 kg carcass weight, but the yield of these carcasses showed quadratic trend, revealing lower percentages at 48.5 and 47.63% replacement levels, respectively. The weights and yields of cuts did not change, except for the posterior arm, whose values showed a cubic trend. Objective measures of carcass, loin eye area, and subjective evaluations of conformation, finishing and marbling of carcasses were not affected. The subcutaneous fat thickness decreased linearly (4.25 to2.48 mm. The inclusion of slow release urea in the diet changes the yield and reduces subcutaneous fat, however, it does not influence other carcass characteristics.

  15. Breathing pattern and head posture: changes in craniocervical angles.

    Science.gov (United States)

    Sabatucci, A; Raffaeli, F; Mastrovincenzo, M; Luchetta, A; Giannone, A; Ciavarella, D

    2015-04-01

    The aim of this study was to observe the influence of oral breathing on head posture and to establish possible postural changes observing the variation of craniocervical angles NSL/OPT and NSL/CVT between oral breathing subjects and physiological breathing subjects. A cross-sectional study was conducted. The sample included 115 subject, 56 boys and 59 girls, 5-22-year-old. Among these, 80 were classified as oral breathers and 35 as physiological breathers. The diagnosis of oral breathing was carried out thanks to characteristic signs and symptoms evaluated on clinical examination, the analysis of characteristic X-ray images, ENT examination with active anterior rhinomanometric (AAR) test. The structural and postural analysis was carried out, calculating the craniofacial angles NSL/OPT and NSL/CVT. Both NSL/OPT and NSL/CVT appear to be significantly greater to those observed in physiological breathing patients. This means that patients who tend to breathe through the mouth rather than exclusively through the nose show a reduction of cervical lordosis and a proinclination of the head. Our study confirms that the oral breathing modifies head position. The significant increase of the craniocervical angles NSL/OPT and NSL/CVT in patients with this altered breathing pattern suggests an elevation of the head and a greater extension of the head compared with the cervical spine. So, to correct the breathing pattern early, either during childhood or during adolescence, can lead to a progressive normalization of craniofacial morphology and head posture.

  16. Lactobacillus reuteri 100-23 modulates urea hydrolysis in the murine stomach.

    Science.gov (United States)

    Wilson, Charlotte M; Loach, Diane; Lawley, Blair; Bell, Tracey; Sims, Ian M; O'Toole, Paul W; Zomer, Aldert; Tannock, Gerald W

    2014-10-01

    Comparisons of in vivo (mouse stomach) and in vitro (laboratory culture) transcriptomes of Lactobacillus reuteri strain 100-23 were made by microarray analysis. These comparisons revealed the upregulation of genes associated with acid tolerance, including urease production, in the mouse stomach. Inactivation of the ureC gene reduced the acid tolerance of strain 100-23 in vitro, and the mutant was outcompeted by the wild type in the gut of ex-Lactobacillus-free mice. Urine analysis showed that stable isotope-labeled urea, administered by gavage, was metabolized to a greater extent in Lactobacillus-free mice than animals colonized by strain 100-23. This surprising observation was associated with higher levels of urease activity and fecal-type bacteria in the stomach digesta of Lactobacillus-free mice. Despite the modulation of urea hydrolysis in the stomach, recycling of urea nitrogen in the murine host was not affected since the essential amino acid isoleucine, labeled with a stable isotope, was detected in the livers of both Lactobacillus-free and 100-23-colonized animals. Therefore, our experiments reveal a new and unexpected impact of Lactobacillus colonization on urea hydrolysis in the murine gut. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  17. Radiation inactivation studies of renal brush border water and urea transport

    International Nuclear Information System (INIS)

    Verkman, A.S.; Dix, J.A.; Seifter, J.L.; Skorecki, K.L.; Jung, C.Y.; Ausiello, D.A.

    1985-01-01

    Radiation inactivation was used to determine the nature and molecular weight of water and urea transport pathways in brush border membrane vesicles (BBMV) isolated from rabbit renal cortex. BBMV were frozen to -50 degrees C, irradiated with 1.5 MeV electrons, thawed, and assayed for transport or enzyme activity. The freezing process had no effect on enzyme or transport kinetics. BBMV alkaline phosphatase activity gave linear ln(activity) vs. radiation dose plots with a target size of 68 +/- 3 kDa, similar to previously reported values. Water and solute transport were measured using the stopped-flow light-scattering technique. The rates of acetamide and osmotic water transport did not depend on radiation dose (0-7 Mrad), suggesting that transport of these substances does not require a protein carrier. In contrast, urea and thiourea transport gave linear ln(activity) vs. dose curves with a target size of 125-150 kDa; 400 mM urea inhibited thiourea flux by -50% at 0 and 4.7 Mrad, showing that radiation does not affect inhibitor binding to surviving transporters. These studies suggest that BBMV urea transport requires a membrane protein, whereas osmotic water transport does not

  18. Synthesis and characterization of new thiourea and urea derivatives ...

    Indian Academy of Sciences (India)

    Hasti Sudhamani et al. N. S/O. O. N. F. O. N. S. O. N ... All the required chemicals were purchased from Sigma. Aldrich and the ... of remaining compounds (8b-g) and urea derivatives. (9a-d). ..... Nicholas J H, John G J, Kendra L B, Paul G C, Harold. B H, Lisa L K ... Nadaradjane A Nicod L Guyon C Xicluna A Robert. J F and ...

  19. Novel route for layered double hydroxides preparation by enzymatic decomposition of urea

    Science.gov (United States)

    Vial, S.; Prevot, V.; Forano, C.

    2006-05-01

    This study presents a new route for the preparation of a series of layered double hydroxide materials with controlled textural properties. It concerns the biogenesis of hydrotalcite like phases by Jack bean urease through the enzymatic decomposition process of urea. Different conditions of LDH biogenesis are investigated (urease activity, urea concentration). A comparative study with the precipitation method based on the thermal decomposition of urea (90 °C) is conducted in order to asses the effect of the various urea hydrolysis conditions (kinetic, temperature) and the presence of enzyme in the reaction medium on the structural and textural properties of the as prepared LDH materials. Mechanisms of formation of the LDH phases for both synthesis processes are discussed on basis of their pH control. The PXRD and SEM analysis of samples prepared by the thermal process evidence higher crystallinity and greater particle sizes than LDH obtained in mild biogenic conditions. In the latter case, presence of urease or effect of some M(II) metals may inhibit the crystallization.

  20. Detection of bronchial breathing caused by pneumonia.

    Science.gov (United States)

    Gross, V; Fachinger, P; Penzel, Th; Koehler, U; von Wichert, P; Vogelmeier, C

    2002-06-01

    The classic auscultation with stethoscope is the established clinical method for the detection of lung diseases. The interpretation of the sounds depends on the experience of the investigating physician. Therefore, a new computer-based method has been developed to classify breath sounds from digital lung sound recordings. Lung sounds of 11 patients with one-sided pneumonia and bronchial breathing were recorded on both the pneumonia side and on contralateral healthy side simultaneously using two microphones. The spectral power for the 300-600 Hz frequency band was computed for four respiratory cycles and normalized. For each breath, the ratio R between the time-segments (duration = 0.1 s) with the highest inspiratory and highest expiratory flow was calculated and averaged. We found significant differences in R between the pneumonia side (R = 1.4 +/- 1.3) and the healthy side (R = 0.5 +/- 0.5; p = 0.003 Wilcoxon-test) of lung. In 218 healthy volunteers we found R = 0.3 +/- 0.2 as a reference-value. The differences of ratio R (delta R) between the pneumonia side and the healthy side (delta R = 1.0 +/- 0.9) were significantly higher compared to follow-up studies after recovery (delta R = 0.0 +/- 0.1, p = 0.005 Wilcoxon-test). The computer based detection of bronchial breathing can be considered useful as part of a quantitative monitoring of patients at risk to develop pneumonia.

  1. Effect of urea on protein-ligand association.

    Science.gov (United States)

    Stepanian, Lora; Son, Ikbae; Chalikian, Tigran V

    2017-12-01

    We combine experimental and theoretical approaches to investigate the influence of a cosolvent on a ligand-protein association event. We apply fluorescence measurements to determining the affinity of the inhibitor tri-N-acetylglucosamine [(GlcNAc) 3 ] for lysozyme at urea concentrations ranging from 0 to 8M. Notwithstanding that, at room temperature and neutral pH, lysozyme retains its native conformation up to the solubility limit of urea, the affinity of (GlcNAc) 3 for the protein steadily decreases as the concentration of urea increases. We analyze the urea dependence of the binding free energy within the framework of a simplified statistical thermodynamics-based model that accounts for the excluded volume effect and direct solute-solvent interactions. The analysis reveals that the detrimental action of urea on the inhibitor-lysozyme binding originates from competition between the free energy contributions of the excluded volume effect and direct solute-solvent interactions. The free energy contribution of direct urea-solute interactions narrowly overcomes the excluded volume contribution thereby resulting in urea weakening the protein-ligand association. More broadly, the successful application of the simple model employed in this work points to the possibility of its use in quantifying the stabilizing/destabilizing action of individual cosolvents on biochemical folding and binding reactions. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Dissolution of lignin in green urea aqueous solution

    Science.gov (United States)

    Wang, Jingyu; Li, Ying; Qiu, Xueqing; Liu, Di; Yang, Dongjie; Liu, Weifeng; Qian, Yong

    2017-12-01

    The dissolution problem is the main obstacle for the value-added modification and depolymerization of industrial lignin. Here, a green urea aqueous solution for complete dissolution of various lignin is presented and the dissolution mechanism is analyzed by AFM, DLS and NMR. The results show that the molecular interaction of lignin decreases from 32.3 mN/m in pure water to 11.3 mN/m in urea aqueous solution. The immobility of 1H NMR spectra and the shift of 17O NMR spectra of urea in different lignin/urea solutions indicate that the oxygen of carbonyl in urea and the hydrogen of hydroxyl in lignin form new hydrogen bonds and break the original hydrogen bonds among lignin molecules. The shift of 1H NMR spectra of lignin and the decrease of interactions in model compound polystyrene indicate that urea also breaks the π-π interactions between aromatic rings of lignin. Lignin dissolved in urea aqueous has good antioxidant activity and it can scavenge at least 63% free radicals in 16 min.

  3. Comparison of PCR and common clinical tests for the diagnosis of H. pylori in dyspeptic patients.

    Science.gov (United States)

    Pacheco, N; Mago, V; Gómez, I; Gueneau, P; Guelrud, M; Reyes, N; Pericchi, L R; Domínguez-Bello, M G

    2001-04-01

    Helicobacter pylori has been recognized as a major gastric pathogen. The objective of this study was to assess the diagnostic value of common clinical tests to detect H. pylori infection, by comparison with PCR. Serum and gastric biopsy specimens from 106 dyspeptic patients were examined. Serology was performed with Pyloriset Dry test, and biopsies were examined histologically, for rapid urease activity and PCR amplification of an ureA gene segment of H. pylori. PCR primers were specific for H. pylori and required at least 1.47 pg of H. pylori DNA, corresponding to about 800 bacterial cells. According to serology, histology, rapid urease, and PCR, positive results were respectively found in 56%, 86%, 64%, and 85% of dyspeptic patients, primarily with gastritis. Relative to PCR, the sensitivity (and specificity) was 55% (38%) for serology, 86% (13%) for histology, 70% (69%) for urease. When combining histology and urease, Bayesian analysis of data indicated no advantage of using combined methods over rapid urease test alone. Histology should not any longer be considered a gold standard test for Helicobacter pylori. Urea breath test still seems the first option for non invasive diagnostic. If an invasive diagnostic is justified, highly specific and sensitive molecular methods should be used to examine specimens.

  4. In vivo proton MRS of normal pancreas metabolites during breath-holding and free-breathing

    International Nuclear Information System (INIS)

    Su, T.-H.; Jin, E.-H.; Shen, H.; Zhang, Y.; He, W.

    2012-01-01

    Aim: To characterize normal pancreas metabolites using in vivo proton magnetic resonance spectroscopy ( 1 H MRS) at 3 T under conditions of breath-holding and free-breathing. Materials and methods: The pancreases of 32 healthy volunteers were examined using 1 H MRS during breath-holding and free-breathing acquisitions in a single-voxel point-resolved selective spectroscopy sequence (PRESS) technique using a 3 T MRI system. Resonances were compared between paired spectra of the two breathing modes. Furthermore, correlations between lipid (Lip) content and age, body-mass index (BMI), as well as choline (Cho) peak visibility of the normal pancreas were analysed during breath-holding. Results: Twenty-nine pairs of spectra were successfully obtained showing three major resonances, Lip, Cho, cholesterol and the unsaturated parts of the olefinic region of fatty acids (Chol + Unsat). Breath-hold spectra were generally better, with higher signal-to-noise ratios (SNR; Z=–2.646, p = 0.008) and Cho peak visible status (Z=–2.449, p = 0.014). Correlations were significant between spectra acquired by the two breathing modes, especially for Lip height, Lip area, and the area of other peaks at 1.9–4.1 ppm. However, the Lip resonance was significantly different between the spectra of the two breathing modes (p 1 H MRS of the normal pancreas at 3 T is technically feasible and can characterize several metabolites. 1 H MRS during breath-holding acquisition is superior to that during free-breathing acquisition.

  5. Determination of urea utilization of rice at different growth stages by 15N tracer technique

    International Nuclear Information System (INIS)

    Korkmaz, A.; Halitligil, M.B.; Torun, M.

    1991-01-01

    This study reported here examines the percent utilization of 15 N labelled urea by rice when it is broadcasted over the soil surface or mixed within 10 cm soil at different vegetative stages. The experimental plots were arranged in randomized block design and replicated 3 times. N was applied at a rate of 120 kg N/ha as single or split applications at four different times during the growing season. Labelled urea was applied to 0.5x0.5 m plots only in 1988, however in 1989 unlabelled urea was applied to all plots. Stover and seed samples from each plot were harvested, dried at 65 0 C, weighed and kilogram per hectare were calculated in 1988. Also, the yield surplus per kilogram N was calculated for each treatment and this was indicated as urea fertilizer efficiency coefficient. Total N and 15 N analysis for stover and seed were done. Significant differences (at 0.05 level) were observed in stover and seed yields, when 120 kg/ha urea was split applied at different growth stages. Similar yield responses were obtained in 1988 and 1989. Highest seed yields were obtained when half of urea was applied at planting and the other half was applied at one week before heading. The results also showed that the highest utilization of urea for seed plus stover was obtained from the second half of urea (60 kg N/ha) applied one week before heading. Percent utilization of urea by rice also differed according to the rate applied at each stage

  6. Role of Some Micro nutrients in Ameliorating the Destructive Effect of Trichloroethylene on Kidney and Testes of Male Rats

    International Nuclear Information System (INIS)

    Nabrawy, F.M.; Ayad, S.K.; Abdou, M.I.; Mohamed, R.Y.; Sharada, H.M.; Abdalla, M.S.

    2012-01-01

    Trichloroethylene (TCE) is a widely used volatile compound to which considerable numbers of human are exposed via breathing , through the skin or through drinking water but rarely through food. The main symptoms of exposure are headache, dizziness, and confusion. Beyond the effects to the central nervous system, workplace exposure to TCE has been associated with toxic effects in many organs including kidney and testes.This work aim to investigate the role of vitamin C and / or zinc against the destructive effect of daily oral TCE intake through biochemical, tissue and DNA studies for kidney and testes during short (3 weeks) and long (15 weeks) terms. Also a hematological study for complete blood count (CBC) has been carried out.The results showed that TCE increases the level of urea creatinine and uric acid and decreases the level of total testosterone significantly. It also showed deformation in tissues and DNA degradation after short and long term treatment with TCE. Administration of vitamin C and/or zinc improved the disrupted effect of TCE oral intake in all the investigated parameters either significantly or non-significantly.It could be conclude d that, both occupational workers and normal people whom may be exposed to TCE can use vitamin C and/ or zinc to compensate the TCE hazardous effect

  7. Optimization of sampling parameters for standardized exhaled breath sampling.

    Science.gov (United States)

    Doran, Sophie; Romano, Andrea; Hanna, George B

    2017-09-05

    The lack of standardization of breath sampling is a major contributing factor to the poor repeatability of results and hence represents a barrier to the adoption of breath tests in clinical practice. On-line and bag breath sampling have advantages but do not suit multicentre clinical studies whereas storage and robust transport are essential for the conduct of wide-scale studies. Several devices have been developed to control sampling parameters and to concentrate volatile organic compounds (VOCs) onto thermal desorption (TD) tubes and subsequently transport those tubes for laboratory analysis. We conducted three experiments to investigate (i) the fraction of breath sampled (whole vs. lower expiratory exhaled breath); (ii) breath sample volume (125, 250, 500 and 1000ml) and (iii) breath sample flow rate (400, 200, 100 and 50 ml/min). The target VOCs were acetone and potential volatile biomarkers for oesophago-gastric cancer belonging to the aldehyde, fatty acids and phenol chemical classes. We also examined the collection execution time and the impact of environmental contamination. The experiments showed that the use of exhaled breath-sampling devices requires the selection of optimum sampling parameters. The increase in sample volume has improved the levels of VOCs detected. However, the influence of the fraction of exhaled breath and the flow rate depends on the target VOCs measured. The concentration of potential volatile biomarkers for oesophago-gastric cancer was not significantly different between the whole and lower airway exhaled breath. While the recovery of phenols and acetone from TD tubes was lower when breath sampling was performed at a higher flow rate, other VOCs were not affected. A dedicated 'clean air supply' overcomes the contamination from ambient air, but the breath collection device itself can be a source of contaminants. In clinical studies using VOCs to diagnose gastro-oesophageal cancer, the optimum parameters are 500mls sample volume

  8. Solubility testing of actinides on breathing-zone and area air samples

    International Nuclear Information System (INIS)

    Metzger, R.L.; Jessop, B.H.; McDowell, B.L.

    1996-02-01

    A solubility testing method for several common actinides has been developed with sufficient sensitivity to allow profiles to be determined from routine breathing zone and area air samples in the workplace. Air samples are covered with a clean filter to form a filter-sample-filter sandwich which is immersed in an extracellular lung serum simulant solution. The sample is moved to a fresh beaker of the lung fluid simulant each day for one week, and then weekly until the end of the 28 day test period. The soak solutions are wet ashed with nitric acid and hydrogen peroxide to destroy the organic components of the lung simulant solution prior to extraction of the nuclides of interest directly into an extractive scintillator for subsequent counting on a Photon-Electron Rejecting Alpha Liquid Scintillation (PERALS reg-sign) spectrometer. Solvent extraction methods utilizing the extractive scintillators have been developed for the isotopes of uranium, plutonium, and curium. The procedures normally produce an isotopic recovery greater than 95% and have been used to develop solubility profiles from air samples with 40 pCi or less of U 3 O 8 . Profiles developed for U 3 O 8 samples show good agreement with in vitro and in vivo tests performed by other investigators on samples from the same uranium mills

  9. 76 FR 78885 - Solid Urea From the Russian Federation and Ukraine: Continuation of Antidumping Duty Orders

    Science.gov (United States)

    2011-12-20

    ... foreseeable time. See Solid Urea From Russia and Ukraine, 76 FR 77015 (December 9, 2011), and ITC Publication... revocation of the antidumping duty orders on solid urea from the Russian Federation (Russia) and Ukraine... Russia and Ukraine,\\1\\ pursuant to section 751(c) of the Tariff Act of 1930, as amended (the Act). See...

  10. Urea utilization in protein deficient rats

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, N [Hyogo College of Medicine, Nishinomiya, Hyogo (Japan)

    1982-06-01

    Three experiments were performed to investigate the mechanism of urea utilization and the nutritional roles of intestinal flora on the utilization of urea by rats fed with a protein deficient diet. Ammonia content in the small intestine in LPD(low protein diet) group fed with a low protein diet for 2 or 5 weeks was about three of five times higher than that of control group fed with SPD(standard protein diet) after administration of urea (0.2gN/100gB.W.). The /sup 15/N incorporation into plasma protein of LPD group was significantly higher than that of the control group two hours after the administration of /sup 15/N-urea (10 mg/100gB.W.) and higher level of /sup 15/N concentration in plasma protein in LPD group was maintained thereafter. The /sup 15/N incorporation into the amino acids of plasma protein was higher in LPD group than in control group. The /sup 15/N incorporation into the amino acids in portal plasma seemed to be higher in LPD group than in control group one hour after the administration of /sup 15/N-urea (10mg/100gB.W.). However, the /sup 15/N incorporation into each free amino acids was suppressed considerably by the administration of antibiotic mixture. it follows that amino acids may be synthesized from urea in the intestine by intestinal-bacterial action and absorbed from portal vein. From these results, it may be concluded that the ammonia nitrogen converted from urea by the action of intestinal-bacterial urease in the intestine is utilized for the synthesis of essential and nonessential amino acids in protein deficient rats and transfered to the liver through portal vein and utilized for protein synthesis.

  11. Urea utilization in protein deficient rats

    International Nuclear Information System (INIS)

    Tanaka, Noriko

    1982-01-01

    Three experiments were performed to investigate the mechanism of urea utilization and the nutritional roles of intestinal flora on the utilization of urea by rats fed with a protein deficient diet. Ammonia content in the small intestine in LPD(low protein diet) group fed with a low protein diet for 2 or 5 weeks was about three of five times higher than that of control group fed with SPD(standard protein diet) after administration of urea (0.2gN/100gB.W.). The 15 N incorporation into plasma protein of LPD group was significantly higher than that of the control group two hours after the administration of 15 N-urea (10 mg/100gB.W.) and higher level of 15 N concentration in plasma protein in LPD group was maintained thereafter. The 15 N incorporation into the amino acids of plasma protein was higher in LPD group than in control group. The 15 N incorporation into the amino acids in portal plasma seemed to be higher in LPD group than in control group one hour after the administration of 15 N-urea (10mg/100gB.W.). However, the 15 N incorporation into each free amino acids was suppressed considerably by the administration of antibiotic mixture. it follows that amino acids may be synthesized from urea in the intestine by intestinal-bacterial action and absorbed from portal vein. From these results, it may be concluded that the ammonia nitrogen converted from urea by the action of intestinal-bacterial urease in the intestine is utilized for the synthesis of essential and nonessential amino acids in protein deficient rats and transfered to the liver through portal vein and utilized for protein synthesis. (J.P.N.)

  12. Spike-Timing of Orbitofrontal Neurons Is Synchronized With Breathing.

    Science.gov (United States)

    Kőszeghy, Áron; Lasztóczi, Bálint; Forro, Thomas; Klausberger, Thomas

    2018-01-01

    The orbitofrontal cortex (OFC) has been implicated in a multiplicity of complex brain functions, including representations of expected outcome properties, post-decision confidence, momentary food-reward values, complex flavors and odors. As breathing rhythm has an influence on odor processing at primary olfactory areas, we tested the hypothesis that it may also influence neuronal activity in the OFC, a prefrontal area involved also in higher order processing of odors. We recorded spike timing of orbitofrontal neurons as well as local field potentials (LFPs) in awake, head-fixed mice, together with the breathing rhythm. We observed that a large majority of orbitofrontal neurons showed robust phase-coupling to breathing during immobility and running. The phase coupling of action potentials to breathing was significantly stronger in orbitofrontal neurons compared to cells in the medial prefrontal cortex. The characteristic synchronization of orbitofrontal neurons with breathing might provide a temporal framework for multi-variable processing of olfactory, gustatory and reward-value relationships.

  13. Spike-Timing of Orbitofrontal Neurons Is Synchronized With Breathing

    Directory of Open Access Journals (Sweden)

    Áron Kőszeghy

    2018-04-01

    Full Text Available The orbitofrontal cortex (OFC has been implicated in a multiplicity of complex brain functions, including representations of expected outcome properties, post-decision confidence, momentary food-reward values, complex flavors and odors. As breathing rhythm has an influence on odor processing at primary olfactory areas, we tested the hypothesis that it may also influence neuronal activity in the OFC, a prefrontal area involved also in higher order processing of odors. We recorded spike timing of orbitofrontal neurons as well as local field potentials (LFPs in awake, head-fixed mice, together with the breathing rhythm. We observed that a large majority of orbitofrontal neurons showed robust phase-coupling to breathing during immobility and running. The phase coupling of action potentials to breathing was significantly stronger in orbitofrontal neurons compared to cells in the medial prefrontal cortex. The characteristic synchronization of orbitofrontal neurons with breathing might provide a temporal framework for multi-variable processing of olfactory, gustatory and reward-value relationships.

  14. Lactose tolerance tests

    Science.gov (United States)

    Hydrogen breath test for lactose tolerance ... Two common methods include: Lactose tolerance blood test Hydrogen breath test The hydrogen breath test is the preferred method. It measures the amount of hydrogen ...

  15. Can salivary creatinine and urea levels be used to diagnose chronic kidney disease in children as accurately as serum creatinine and urea levels? A case-control study.

    Science.gov (United States)

    Renda, Rahime

    2017-11-01

    Children with chronic kidney disease (CKD) develop many metabolic changes in blood that often necessitate frequent biochemical analysis. Serum analysis is an invasive and painful procedure. It would be highly beneficial if a noninvasive alternative process to serum analysis in children were identified. Saliva can be collected noninvasively, repeatedly, and without the use of healthcare personnel. The aims of this study were to compare serum and salivary urea and creatinine levels in children with CKD and healthy controls, and to determine if salivary creatinine and urea levels can be used to diagnose CKD in children as accurately as serum creatinine and urea levels. This case-control study included 35 children with CKD and 28 healthy children as controls. Saliva and blood samples were collected for measurement of urea and creatinine levels. The urea and creatinine levels in serum and saliva in the CKD and control groups were compared using the independent samples Mann-Whitney U test. Correlations between the serum and salivary urea and creatinine levels were determined using Pearson's correlation coefficient. Receiver operating characteristic analysis was used to assess the diagnostic performance of salivary creatinine and cutoff values were identified. In the CKD group, the mean salivary creatinine level was 0.45 mg/dL and the mean salivary urea level was 0.11 mg/dL, versus 28.83 mg/dL and 21.78 mg/dL, respectively, in the control group. Stage 4 and 5 CKD patients had a mean salivary urea level of 31.35 mg/dL, as compared to 17.78 mg/dL in the control group. Serum urea and creatinine, and salivary creatinine were significantly higher in the CKD patients (regardless of disease stage) than in the controls (p creatinine. The area under the curve for salivary creatinine was 0.805. The cutoff value for salivary creatinine was 0.125 mg/dL, with a sensitivity of 82.9% and specificity of 78.6%. Based on the positive correlation between the serum and saliva

  16. Lipase-catalyzed synthesis of fatty acid amide (erucamide) using fatty acid and urea.

    Science.gov (United States)

    Awasthi, Neeraj Praphulla; Singh, R P

    2007-01-01

    Ammonolysis of fatty acids to the corresponding fatty acid amides is efficiently catalysed by Candida antartica lipase (Novozym 435). In the present paper lipase-catalysed synthesis of erucamide by ammonolysis of erucic acid and urea in organic solvent medium was studied and optimal conditions for fatty amides synthesis were established. In this process erucic acid gave 88.74 % pure erucamide after 48 hour and 250 rpm at 60 degrees C with 1:4 molar ratio of erucic acid and urea, the organic solvent media is 50 ml tert-butyl alcohol (2-methyl-2-propanol). This process for synthesis is economical as we used urea in place of ammonia or other amidation reactant at atmospheric pressure. The amount of catalyst used is 3 %.

  17. Effect of dietary nitrogen content and intravenous urea infusion on ruminal and portal-drained visceral extraction of arterial urea in lactating Holstein cows.

    Science.gov (United States)

    Kristensen, N B; Storm, A C; Larsen, M

    2010-06-01

    Urea extraction across ruminal and portal-drained visceral (PDV) tissues were investigated using 9 rumen-cannulated and multi-catheterized lactating dairy cows adapted to low-N (12.9% crude protein) and high-N (17.1% crude protein) diets in a crossover design. The interaction between adaptation to dietary treatments and blood plasma concentrations of urea was studied by dividing samplings into a 2.5-h period without urea infusion followed by a 2.5-h period with primed continuous intravenous infusion of urea (0.493+/-0.012 mmol/kg of BW per h). Cows were sampled at 66+/-14 and 68+/-12 d in milk and produced 42+/-1 and 36+/-1 kg of milk/d with the high-N and low-N diets, respectively. The arterial blood urea concentration before urea infusion was 1.37 and 4.09+/-0.18 mmol/L with low-N and high-N, respectively. Dietary treatment did not affect the urea infusion-induced increase in arterial urea concentration (1.91+/-0.13 mmol/L). Arterial urea extraction across the PDV and rumen increased from 2.7 to 5.4+/-0.5% and from 7.1 to 23.8+/-2.1% when cows were changed from high-N to low-N, respectively. Urea infusion did not decrease urea extractions, implying that urea transport rates were proportional to arterial urea concentrations. Urea extraction increased more across the rumen wall than across the total PDV for low-N compared with high-N, which implies that a larger proportion of total PDV uptake of arterial urea is directed toward the rumen with decreasing N intake. The ruminal vein - arterial (RA) concentration difference for ammonia increased instantly (first sampling 15 min after initiation of infusion) to the primed intravenous infusion when cows were adapted to the low-N diet. The RA difference for ammonia correlated poorly to the ventral ruminal concentration of ammonia (r=0.55). Relating the RA difference for ammonia to a function of both ruminal ammonia concentration and the RA difference for urea markedly improved the fit (r=0.85), indicating that a large

  18. A cross-sectional study of breath acetone based on diabetic metabolic disorders.

    Science.gov (United States)

    Li, Wenwen; Liu, Yong; Lu, Xiaoyong; Huang, Yanping; Liu, Yu; Cheng, Shouquan; Duan, Yixiang

    2015-02-26

    Breath acetone is a known biomarker for diabetes mellitus in breath analysis. In this work, a cross-sectional study of breath acetone based on clinical metabolic disorders of type 2 diabetes mellitus (T2DM) was carried out. Breath acetone concentrations of 113 T2DM patients and 56 apparently healthy individuals were measured at a single time point. Concentrations varied from 0.22 to 9.41 ppmv (mean 1.75 ppmv) for T2DM, which were significantly higher than those for normal controls (ranged from 0.32 to 1.96 ppmv, mean 0.72 ppmv, p = 0.008). Observations in our work revealed that breath acetone concentrations elevated to different degrees, along with the abnormality of blood glucose, glycated hemoglobin (HbA1c), triglyceride and cholesterol. Breath acetone showed obviously positive correlations with blood ketone and urine ketone. Possible metabolic relations between breath acetone and diabetic disorders were also discussed. This work aimed at giving an overall assessment of breath acetone from the perspective of clinical parameters for type 2 diabetes.

  19. Urea and deuterium mixtures at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, M., E-mail: m.donnelly-2@sms.ed.ac.uk; Husband, R. J.; Frantzana, A. D.; Loveday, J. S. [Centre for Science at Extreme Conditions and School of Physics and Astronomy, The University of Edinburgh, Erskine Williamson Building, Peter Guthrie Tait Road, The King’s Buildings, Edinburgh EH9 3FD (United Kingdom); Bull, C. L. [ISIS, Rutherford Appleton Laboratory, Oxford Harwell, Didcot OX11 0QX (United Kingdom); Klotz, S. [IMPMC, CNRS UMR 7590, Université P and M Curie, 4 Place Jussieu, 75252 Paris (France)

    2015-03-28

    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D{sub 2} mixtures that indicate no inclusion compound forms up to 3.7 GPa.

  20. Breath-hold duration in man and the diving response induced by face immersion.

    Science.gov (United States)

    Sterba, J A; Lundgren, C E

    1988-09-01

    The objective of this study in 5 selected volunteer subjects was to see whether the circulatory diving response which is elicited by breath holding and by cold water on the face would affect the duration of maximal-effort breath holds. Compared to control measurements (breath holding during resting, breathing with 35 degrees C water on the face) breath holding with the face cooled by 20 degrees C water caused a 12% reduction of heart rate, 6% reduction of cardiac output, 33% reduction in [corrected] forearm blood flow, and 9% rise in mean arterial blood pressure, but there was no difference in breath-hold duration (control and experimental both 94 s). There were also no differences in time of appearance of the first involuntary respiratory efforts during breath holding, in alveolar gas exchange, or in breaking-point alveolar O2 and CO2 tensions. When the diving response was magnified by a brief bout of exercise so that there was a 19% [corrected] reduction in heart rate, 23% reduction in cardiac output, and 48% reduction in forearm blood flow, breath-hold duration was still unaffected by face cooling. Compared to intermittent immersions, continuous exposure of the face to cold water abolished the diving response, probably by a cold adaptation of facial thermal receptors. These results with cooling of the face only are consistent with our earlier finding that there was a negative correlation between the duration of a maximal-effort breath hold and the diving response during whole-body submersion in cold water.

  1. Clinical chemistry measurements with commercially available test slides on a smartphone platform: Colorimetric determination of glucose and urea.

    Science.gov (United States)

    Wu, Yuanyuan; Boonloed, Anukul; Sleszynski, Neal; Koesdjojo, Myra; Armstrong, Chadd; Bracha, Shay; Remcho, Vincent T

    2015-08-25

    Rapidly increasing healthcare costs in economically advantaged countries are currently unsustainable, while in many developing nations, even 50-year-old technologies are too expensive to implement. New and unconventional technologies are being explored as solutions to this problem. In this study, we examined the use of a smartphone as the detection platform for 2 well-developed, relatively inexpensive, commercially available clinical chemistry assays as a model for rapid and inexpensive clinical diagnostic testing. An Apple iPhone 4 camera phone equipped with a color analysis application (ColorAssist) was combined with Vitros® glucose and urea colorimetric assays. Color images of assay slides at various concentrations of glucose or urea were collected with the iPhone 4 and quantitated in three different spectral ranges (red/green/blue or RGB) using the ColorAssist app. When the diffuse reflectance data was converted into absorbance, it was possible to quantitate glucose or blood urea nitrogen (BUN) over their clinically important concentration ranges (30-515mg/dl for glucose or 2-190mg/dl for BUN), with good linearity (R(2)=0.9994 or 0.9996, respectively [n=5]). Data collected using the iPhone 4 and canine serum samples were in agreement with results from the instrumental "gold standard" (Beckman Coulter AU480 Chemistry System) (R(2)=0.9966 and slope=1.0001 for glucose; R(2)=0.9958 and slope=0.9454 for BUN). Glucose determinations of serum samples made using this smartphone method were as accurate as or more accurate than a commercial colorimetric dry slide analyzer (Heska® Element DC Chemistry Analyzer, Loveland, CO) and 2 glucometers: ReliOn® Ultima (Abbott Diabetes Care Inc) and Presto® (AgaMatrix Inc.H). BUN determinations made using the smartphone approach were comparable in accuracy to the Heska instrument. This demonstration shows that smartphones have the potential to be used as simple, effective colorimetric detectors for quantitative diagnostic tests

  2. Effect of Microbial Interaction on Urea Metabolism in Chinese Liquor Fermentation.

    Science.gov (United States)

    Wu, Qun; Lin, Jianchun; Cui, Kaixiang; Du, Rubin; Zhu, Yang; Xu, Yan

    2017-12-20

    Urea is the primary precursor of the carcinogen ethyl carbamate in fermented foods. Understanding urea metabolism is important for controlling ethyl carbamate production. Using Chinese liquor as a model system, we used metatranscriptome analysis to investigate urea metabolism in spontaneous food fermentation processes. Saccharomyces cerevisiae was dominant in gene transcription for urea biosynthesis and degradation. Lysinibacillus sphaericus was dominant for urea degradation. S. cerevisiae degraded 18% and L. sphaericus degraded 13% of urea in their corresponding single cultures, whereas they degraded 56% of urea in coculture after 12 h. Compared to single cultures, transcription of CAR1, DAL2, and argA, which are related to urea biosynthesis, decreased by 51, 36, and 69% in coculture, respectively. Transcription of DUR1 and ureA, which are related to urea degradation, increased by 227 and 70%, respectively. Thus, coexistence of the two strains promoted degradation of urea via transcriptional regulation of genes related to urea metabolism.

  3. Effects of high-frequency yoga breathing called kapalabhati compared with breath awareness on the degree of optical illusion perceived.

    Science.gov (United States)

    Telles, Shirley; Maharana, Kanchan; Balrana, Budhi; Balkrishna, Acharya

    2011-06-01

    Prior research has shown that methods of meditation, breath control, and different kinds of yoga breathing affect attention and visual perception, including decreasing the size of certain optical illusions. Evaluating relationships sheds light on the perceptual and cognitive changes induced by yoga and related methods, and the locus of the effects. In the present study, the degree of optical illusion was assessed using Müller-Lyer stimuli before and immediately after two different kinds of practice, a high frequency yoga breathing called kapalabhati, and breath awareness. A nonyoga, control session tested for practice effects. Thirty participants (with group M age = 26.9 yr., SD = 5.7) practiced the two techniques for 18 min. on two separate days. The control group had 15 nonyoga practitioners assessed before and after 18 min. in which they did not perform any specific activity but were seated and relaxed. After both kapalabhati and breath awareness there was a significant decrease in the degree of optical illusion. The possibility that this was due to a practice or repetition effect was ruled out when 15 nonyoga practitioners showed no change in the degree of illusion when retested after 18 min. The changes were interpreted as due to changes in perception related to the way the stimuli were judged.

  4. A simple, remote, video based breathing monitor.

    Science.gov (United States)

    Regev, Nir; Wulich, Dov

    2017-07-01

    Breathing monitors have become the all-important cornerstone of a wide variety of commercial and personal safety applications, ranging from elderly care to baby monitoring. Many such monitors exist in the market, some, with vital signs monitoring capabilities, but none remote. This paper presents a simple, yet efficient, real time method of extracting the subject's breathing sinus rhythm. Points of interest are detected on the subject's body, and the corresponding optical flow is estimated and tracked using the well known Lucas-Kanade algorithm on a frame by frame basis. A generalized likelihood ratio test is then utilized on each of the many interest points to detect which is moving in harmonic fashion. Finally, a spectral estimation algorithm based on Pisarenko harmonic decomposition tracks the harmonic frequency in real time, and a fusion maximum likelihood algorithm optimally estimates the breathing rate using all points considered. The results show a maximal error of 1 BPM between the true breathing rate and the algorithm's calculated rate, based on experiments on two babies and three adults.

  5. The effects of a hind-gut fermentation on urea kinetics in sheep

    International Nuclear Information System (INIS)

    Oncuer, A.

    1988-01-01

    Four female sheep were fitted with rumen cannulas and abomasal and ileal infusion catheters; one of the sheep was also fitted with a cannula at the caecum. All animals were nourished wholly by intragastric infusion of nutrients to the rumen and abomasum and received in addition three levels of nutrient infusion into the terminal ileum in order to achieve different levels of hind-gut fermentation. The ileal infusion treatments were (1) water infusion; (2) 25 g/d starch and 50 g/d cellulose infusion; (3) 50 g/d starch and 50 g/d cellulose infusion. In each 2 week period, the first 7 days served as the preliminary period infusion. Days 8-12 inclusive were used for quantitative collection of faeces and urine for digestibility and nitrogen balance measurement and on day 14 an injection of ( 14 C)-urea was given into a jugular vein for measurement of urea kinetics. Hind-gut fermentation did not significantly affect any parameters of urea metabolism. Although degradation of urea did not differ significantly between treatments an increase of over 2 g/d was observed in progressing from the lowest to the highest level of hind-gut infusion. Faecal nitrogen excretion increased significantly from 21.8 to 74.7 mg N/kg 0.75 /d (P 0.01) and urinary urea-N decreased significantly from 278.9 to 252.3 mg/kg 0.75 /d (P 0.05) in the presence of a hind-gut fermentation. Close relationships were observed between various parameters of urea metabolism

  6. Hardness evaluation of cured urea-formaldehyde resins with different formaldehyde/urea mole ratios using nanoindentation method

    Science.gov (United States)

    Byung-Dae Park; Charles R. Frihart; Yan Yu; Adya P. Singh

    2013-01-01

    To understand the influence of formaldehyde/urea (F/U) mole ratio on the properties of urea–formaldehyde (UF) resins, this study investigated hardness of cured UF resins with different F/U mole ratios using a nanoindentation method. The traditional Brinell hardness (HB) method was also used...

  7. Effect of rumen-degradable intake protein supplementation on urea kinetics and microbial use of recycled urea in steers consuming low-quality forage.

    Science.gov (United States)

    Wickersham, T A; Titgemeyer, E C; Cochran, R C; Wickersham, E E; Gnad, D P

    2008-11-01

    We evaluated the effect of increasing amounts of rumen-degradable intake protein (DIP) on urea kinetics in steers consuming prairie hay. Ruminally and duodenally fistulated steers (278 kg of BW) were used in a 4 x 4 Latin square and provided ad libitum access to low-quality prairie hay (4.9% CP). The DIP was provided as casein dosed ruminally once daily in amounts of 0, 59, 118, and 177 mg of N/kg of BW daily. Periods were 13 d long, with 7 d for adaptation and 6 d for collection. Steers were in metabolism crates for total collection of urine and feces. Jugular infusion of (15)N(15)N-urea, followed by determination of urinary enrichment of (15)N(15)N-urea and (14)N(15)N-urea was used to determine urea kinetics. Forage and N intake increased (linear, P Urea synthesis was 19.9, 24.8, 42.9, and 50.9 g of urea-N/d for 0, 59, 118, and 177 mg of N/kg of BW daily (linear, P = 0.004). Entry of urea into the gut was 98.9, 98.8, 98.6, and 95.9% of production for 0, 59, 118, and 177 mg of N/kg of BW daily, respectively (quadratic, P = 0.003). The amount of urea-N entering the gastrointestinal tract was greatest for 177 mg of N/kg of BW daily (48.6 g of urea-N/d) and decreased (linear, P = 0.005) to 42.4, 24.5, and 19.8 g of urea-N/d for 118, 59, and 0 mg of N/kg of BW daily. Microbial incorporation of recycled urea-N increased linearly (P = 0.02) from 12.3 g of N/d for 0 mg of N/kg of BW daily to 28.9 g of N/d for 177 mg of N/kg of BW daily. Provision of DIP produced the desired and previously observed increase in forage intake while also increasing N retention. The large percentage of urea synthesis that was recycled to the gut (95.9% even when steers received the greatest amount of DIP) points to the remarkable ability of cattle to conserve N when fed a low-protein diet.

  8. Breath Tests in Respiratory and Critical Care Medicine: From Research to Practice in Current Perspectives

    Directory of Open Access Journals (Sweden)

    Attapon Cheepsattayakorn

    2013-01-01

    Full Text Available Today, exhaled nitric oxide has been studied the most, and most researches have now focusd on asthma. More than a thousand different volatile organic compounds have been observed in low concentrations in normal human breath. Alkanes and methylalkanes, the majority of breath volatile organic compounds, have been increasingly used by physicians as a novel method to diagnose many diseases without discomforts of invasive procedures. None of the individual exhaled volatile organic compound alone is specific for disease. Exhaled breath analysis techniques may be available to diagnose and monitor the diseases in home setting when their sensitivity and specificity are improved in the future.

  9. Radiation-induced in-source polymerization of acrylonitrile in urea canal complex

    International Nuclear Information System (INIS)

    Yoshii, Fumio; Abe, Toshihiko; Kobayashi, Yasushi.

    1975-01-01

    Effect of reaction conditions on the radiation-induced in-source polymerization of acrylonitrile in urea canal complex and the properties of obtained polyacrylonitriles were investigated. The results were discussed in comparison with previously reported of the post-polymerization experiments. 1) Rate of polymerization and viscosity (eta sub(sp)/C) were the highest when the molar ratio of acrylonitrile to urea in canal complex was unity. Similar results were also obtained in the post-polymerization. However, eta sub(sp)/C exhibited different behavior on polymerization time in comparison with post-polymerization. 2) The initial rate (Rsub(p)) of polymerization is proportional to the dose rate (I) at low dose rate, but at high dose rates (above 2x10 5 r/hr) makes Rsub(p) proportional to Isup(0.5). 3) Molecular weight distribution become broader with increasing polymerization time and is broad as compared with those obtained by the post-polymerization. G-value of initiation of polymerization decreased with increasing polymerization time. These value was larger than the that obtained in the post-polymerization. 4) The stereoregularity of the polyacrylonitriles was independent of the molar ratio of acrylonitrile to urea in the canal complex and conversion. 5) The appearance of the polyacrylonitriles observed by the scanning electron microscope changed from curled string to extended one as the polymerization proceed. 6) Infrared spectrum revealed the ketenimine and cyclization structure in the polyacrylonitriles obtained below -100 0 C. The content of these abnormal structures increased with increasing conversion. (auth.)

  10. What Causes Bad Breath?

    Science.gov (United States)

    ... Videos for Educators Search English Español What Causes Bad Breath? KidsHealth / For Teens / What Causes Bad Breath? Print en español ¿Qué es lo que provoca el mal aliento? Bad breath, or halitosis , can be a major problem, ...

  11. Synthesis of 15N-labelled urea and methylenediurea

    International Nuclear Information System (INIS)

    Murray, T.P.; Jones, G.T.

    1985-01-01

    A new technique was developed for the large-scale synthesis of 15 N-labelled urea at low enrichment levels. The synthesis is based on nucleophilic displacement of the phenoxide ion from phenyl carbonate and uses anhydrous ammonia as the nucleophile. In previous reports a copper catalyst was used; however, in this study it was found that the copper resulted in product decomposition and tar formation, which makes product purification difficult. A novel set of reaction conditions was developed: no catalyst was used, and no product decomposition or tar formation occurred. The reaction product was easily purified, and consistently high yields of 15 N-labelled urea were obtained. 15 N-labelled methylenediurea was prepared by the dilute solution reaction of formalin with 15 N-labelled urea. The methodology developed for the reclamation of unreacted urea resulted in minimum loss of labelled urea. High performance liquid chromatography has been used to determine the chemical purity of both urea and methylenediurea. (author)

  12. Organic compounds preparation with 14 C

    International Nuclear Information System (INIS)

    Shirvani, Gholam Hossein.

    1996-09-01

    Active urea is a basic reagent for the synthesis of active uric-8- 14 C acid. In our manner, activated Barium carbonate with specified activity was placed in a special furnace with ability of passing gases. Then, ammonia gas was passed through it at about 850 Degree C to obtain Barium Cyanamide. Reaction of the produced compound with CO 2 , and then acidification of the mixture, gave activated urea. Condensation of the urea with Ethylcyanoacetate, produce 6-Aminouracil which upon nitrosation, reduction and then condensation with urea, the desired Uric-8- 14 C acid was synthesized. (author). 148 refs.,

  13. Noise Reduction in Breath Sound Files Using Wavelet Transform Based Filter

    Science.gov (United States)

    Syahputra, M. F.; Situmeang, S. I. G.; Rahmat, R. F.; Budiarto, R.

    2017-04-01

    The development of science and technology in the field of healthcare increasingly provides convenience in diagnosing respiratory system problem. Recording the breath sounds is one example of these developments. Breath sounds are recorded using a digital stethoscope, and then stored in a file with sound format. This breath sounds will be analyzed by health practitioners to diagnose the symptoms of disease or illness. However, the breath sounds is not free from interference signals. Therefore, noise filter or signal interference reduction system is required so that breath sounds component which contains information signal can be clarified. In this study, we designed a filter called a wavelet transform based filter. The filter that is designed in this study is using Daubechies wavelet with four wavelet transform coefficients. Based on the testing of the ten types of breath sounds data, the data is obtained in the largest SNRdB bronchial for 74.3685 decibels.

  14. 13CO2 breath test to measure the hydrolysis of various starch formulations in healthy subjects.

    OpenAIRE

    Hiele, M; Ghoos, Y; Rutgeerts, P; Vantrappen, G; de Buyser, K

    1990-01-01

    13CO2 starch breath test was used to study the effect of physicochemical characteristics of starch digestion. As starch is hydrolysed to glucose, which is subsequently oxidised to CO2, differences in 13CO2 excretion after ingestion of different starch products must be caused by differences in hydrolysis rate. To study the effect of the degree of chain branching, waxy starch, containing 98% amylopectin, was compared with high amylose starch, containing 30% amylopectin, and normal crystalline s...

  15. Comparison of CO breath testing and women's self-reporting of smoking behaviour for identifying smoking during pregnancy

    Directory of Open Access Journals (Sweden)

    Shipton Deborah

    2008-02-01

    Full Text Available Abstract Background Healthcare services often use a carbon monoxide (CO breath test to validate self-reported smoking and to assess reductions in smoking habit. A cut-off level of ≥ 8 parts per million (p.p.m. is used to identify smoking. This cut-off requires further validation in pregnant women. Methods Data on self-reported smoking were assessed in conjunction with breath CO level