Urea transport across dog intestinal mucosa in vitro

Hakim, A A; Lifson, Nathan

doi:10.1152/ajplegacy.1964.206.6.1315

Cited by 25 publications

(6 citation statements)

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“…Such a high level of calcium can be accounted for, if some sort of concentrating mechanism is involved within the crevice. Golub et al (1971) have also found a similar hyperconcentratitig effect in the levels of urea in the crevice fluid, in agreement with our findings (Biswas et al 1977), and they have suggested that either an active transport process results in the hyperconcentration of urea or that the passage of water from the tissues in the crevicular space is slower than that of urea (Hakim & Lifson 1964). Under the same argument, the hyperconcentration of calcium (approx.…”

Section: Discussionsupporting

confidence: 91%

Study of crevice fluid in relation to periodontal disease in children

Biswas

Duperon

Chebib

1977

J of Periodontal Research

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Crevicular fluid from four groups of children was examined. The crevice fluid was collected at random from the anterior region of the mouth (6 distal and 6 mesial) in filter paper strips and the volume of the ascending fluid in each strip was measured by techniques previously described by Smith, Golub & Duperon (1974). Gingival condition was assessed on the basis of the Löe and Silness Index (1963). The crevice fluid was pooled on the basis of age, sex and gingival inflammation, and each pool was analyzed for protein, carbohydrate, total calcium, phosphate and nitrogen. Protein and carbohydrate were analyzed by taking an aliquot of the pooled sample directly, whereas total calcium content, phosphate and nitrogen were analyzed in a sample digested with concentrated sulfuric acid and 30 per cent (V/V) hydrogen peroxide. Standard chromogenic reagents were used in analysis. Each component was regarded as a single variable. In this study the corresponding means were compared and graphed. The results were presented as the effects of age, sex and G. I. and various interactions. The data was analyzed to determine i) the absolute quantity of each component and ii) the concentration of each (μg/μl) in the crevice fluid. The concentration of protein in the fluid was higher in females than in males and was also higher in the post‐pubertal group than in the pre‐pubertal group. The concentration of carbohydrate and calcium followed almost the same trend as that of protein. The difference in the concentration of phosphate was not significant. The levels of calcium and phosphate were several times higher than serum levels, indicating that calcium and phosphate were hyperconcentrated within the crevice overnight, as occurred with urea (Golub, Borden & Kleinberg 1971). The high protein content may be related to the high urea content of the crevice fluid from inflamed gingivae. The high urea content will give rise to a high pH‐a pH which can be favourable to the calcification process. Also, the hyperconcentration of calcium and phosphate, particularly in the post‐pubertal group, may favour this process.

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Section: Discussionsupporting

confidence: 91%

Study of crevice fluid in relation to periodontal disease in children

Biswas

Duperon

Chebib

1977

J of Periodontal Research

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“…where Y is the mean NH,-N concentration in the digesta of the caecum and proximal colon (mg NH,-N/I), and X is the blood urea concentration (mg N / Q These results for sheep are in agreement with observations of transfer of blood urea into the small intestine in dogs (Hakim & Lipson, 1964) and in sheep (Hecker, 1971b;Boda et al 1976). If the concentration of urea in ileal water and blood were equal, on the basis of estimates of ileal digesta flow in similar sheep , up to 1.5 g urea-N/d could have entered the caecum in ileal digesta.…”

Section: Transfer Of Blood Urea-n To Various Sections Of the Gastroinsupporting

confidence: 86%

Nitrogen and carbon flows between the caecum, blood and rumen in sheep given chopped lucerne (Medicago sativa) hay

Dixon

Nolan

1986

Br J Nutr

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I . Experiments involving I5N and 14C tracers were made in sheep consuming 800 g air-dry chopped lucerne I Merlicugo sativa) hay/d and providing 20.4 g N/d to study N and C flows within the caecal digesta and between i he caecum, blood and rumen.2. Continuous infusions of 15N tracers were made into the caecal ammonia, blood urea and rumen NH, pools. The concentration and enrichment of caecal digesta NH,-N, caecal microbial N, caecal digesta non-urea. non-ammonia-N (NU-NAN), faecal NU-NAN, blood urea-N, rumen digesta NH,-N and rumen bacterial N were estimated at intervals during the infusions. A three-pool open-compartment model was solved to estimate N flows between the caecal digesta NH,-N, blood urea-N and rumen digesta NH,-N pools.3. The rate of irreversible loss from the caecal digesta NH,-N pool was 2. The urea hydrolysed in the gastrointestinal tract other than in the rumen digesta pool and the caecal digesta pool was 0.56 of total urea hydrolysis when estimated with 14C tracers, or 0.69 when estimated with 'jN tracers. Results from previous acute experiments suggested that with three of the four observations made in three sheep in the present experiment the transfer of blood urea to the caecal digesta could have occurred entirely via ileal digesta. Similarly, urea transfer to the rumen digesta could have occurred entirely via saliva.

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“…The relation between hydrostatic pressure and transmucosal fluid move ment was recently reexamined in an in vitro preparation in which sheets of intestinal mucosa were tied over the end of a glass cylinder (72)(73)(74). The results were felt to be relevant to in vivo intestinal function because water transport from isotonic Krebs-bicarbonate Ringer solution depended on the presence of glucose in the mucosal solution, water was absorbed against an activity gradient, and uphill glucose movement and chloride impoverishment from the mucosal fluid were observed.…”

Section: Filtrationmentioning

confidence: 99%