A New Simple Semimicro Method for Colorimetric Determination of Urea

Coulombe, J. J.; Favreau, Leonard

doi:10.1093/clinchem/9.1.102

Cited by 498 publications

(124 citation statements)

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“…In numerous experiments commercial bovine liver arginase (Serva, Heidelberg) was used. Activity was measured on the basis of urea release over 30 rain, urea being determined with diacetylmonoxime-thiosemicarbazide reagent using a spectrophotometric method [19].…”

Section: Purification and Measurement Of Arginasementioning

confidence: 99%

“…Adhered murine peritoneal macrophages were cultured in DMEM containing 10 mM Arg and 1 10 mM nitrite in an FBS-free DMEM for 24 h at 37°C under a 5% CO2 atmosphere. Supernatants of these cultures were tested for urea production by a spectrophotometric method [19]. Cell-free samples were tested at each nitrite concentra-~014-5793/96l$12.00 © 1996 Federation of European Biochemical Societies.…”

Section: Measurement Of Urea As Product Of Arginase Action In Intact mentioning

confidence: 99%

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The inhibitory effect of nitrite, a stable product of nitric oxide (NO) formation, on arginase

et al. 1996

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Macrophages contain arginase and an inducible NO synthase, demonstrated by using L-arginine, the common substrate, for production of both nitric oxide and urea. Arginase was inhibited by nitrite, the stable end product of NO. This inhibition was non-competitive, and could not be explained by the reaction of nitrite with arginine, or by the irreversible covalent modification of arginase, or by the removal of Mn 2+, a cofactor of arginase.

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Section: Purification and Measurement Of Arginasementioning

confidence: 99%

Section: Measurement Of Urea As Product Of Arginase Action In Intact mentioning

confidence: 99%

The inhibitory effect of nitrite, a stable product of nitric oxide (NO) formation, on arginase

et al. 1996

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“…The concentrations of total protein and inorganic phosphate were determined in both types of saliva by calorimetric techniques, chloride by a coulometric method and sodium, potassium and calcium by atomic absorption spectroscopy as described previously (Dawes, 1967b. Urea was analysed by the method of Coulombe & Favreau (1963), in saliva collected from six of the eight subjects. Preliminary studies showed that when saliva was kept in ice water for 3 days there was no change in the measured concentrations of the above components except for urea.…”

Section: Analytical Techniquesmentioning

confidence: 99%

Circadian rhythms in human salivary flow rate and composition

Dawes¹

1972

The Journal of Physiology

552

368

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SUMMARY1. Unstimulated whole saliva and parotid saliva stimulated at a constant flow rate of 1-0 ml./min were collected from eight subjects at about 07.00, 11.00, 14.00, 17.00 and 22.00 hr and oral temperature was recorded several times daily for time spans of between 4 and 26 days. A leastsquares cosine wave was fitted to the data to test for the presence and characteristics of circadian rhythms. 2. Estimates of mean level, amplitude, acrophase and period were obtained for different components and the results were subjected to cosinor analysis.3. Unstimulated whole saliva showed significant circadian rhythms in flow rate and in the concentrations of sodium and chloride but not in protein, potassium, calcium, phosphate or urea.4. Stimulated parotid saliva showed significant circadian rhythms in the concentrations of protein, sodium, potassium, calcium and chloride but not in phosphate or urea 5. Oral temperature showed a circadian rhythm which, like the salivary rhythms, was of a 24.0 hr periodicity.

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“…The serum glucose concentration was measured using mutaroze [11] (Wako test kit). The serum urea nitrogen concentration was measured using diacetylmonoxime [12] (Wako test kit). The serum triglyceride concentration was measured using GPO·DAOS [13] (Wako test kit).…”

Section: Measurement Of Serum Componentsmentioning

confidence: 99%

Changes of glucose metabolism and skin-collagen neogenesis in vitamin B₆deficiency

et al. 2005

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The mechanism of pellagrous changes in skin caused by a deficiency of vitamin B6 was studied in respect to neogenesis of proline in skin collagen and glucose metabolism. In vitamin B6 deficiency the insulin/glucagon coefficient in serum decreased significantly from 3.02 to 2.32, indicating a metabolic change towards gluconeogenesis. A deficiency of vitamin B6 caused a decrease in the levels of vitamin B6-dependent enzymes, such as ornithine aminotransferase, alanine aminotransferase, and aspartate aminotransferase, which also contribute to gluconeogenesis. Because the conversion of ornithine to proline via pyrroline-5-carboxylate was suppressed due to the decrease in ornithine aminotransferase activity, the amount of proline in the skin collagen fraction also decreased significantly in vitamin B6-deficient rats compared with the pair-fed control. These results suggest that the pellagrous lesions in vitamin B6-deficiency are caused by an impaired synthesis of proline from ornithine, which results in the suppression of collagen neogenesis in the skin.

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A New Simple Semimicro Method for Colorimetric Determination of Urea

Cited by 498 publications

References 0 publications

The inhibitory effect of nitrite, a stable product of nitric oxide (NO) formation, on arginase

The inhibitory effect of nitrite, a stable product of nitric oxide (NO) formation, on arginase

Circadian rhythms in human salivary flow rate and composition

Changes of glucose metabolism and skin-collagen neogenesis in vitamin B₆deficiency

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A New Simple Semimicro Method for Colorimetric Determination of Urea

Cited by 498 publications

References 0 publications

The inhibitory effect of nitrite, a stable product of nitric oxide (NO) formation, on arginase

The inhibitory effect of nitrite, a stable product of nitric oxide (NO) formation, on arginase

Circadian rhythms in human salivary flow rate and composition

Changes of glucose metabolism and skin-collagen neogenesis in vitamin B6deficiency

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Product

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Changes of glucose metabolism and skin-collagen neogenesis in vitamin B₆deficiency