Carbamylated haemoglobin—a retrospective index of time-averaged urea concentration

Kwan, Jonathan; Carr, E. C.; Barron, Jeffrey; Bending, M. R.

doi:10.1093/ndt/8.6.565

Cited by 15 publications

(8 citation statements)

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“…A single HbA 1c determination reflects the time-averaged serum glucose concentration for the preceding 2–3 months. Similarly, the previous observations showed the significant correlation between carbHb and BUN for the previous 2 months in uremic patients with and without dialysis [23]. …”

Section: Discussionsupporting

confidence: 79%

Carbamylated Hemoglobin as a Therapeutic Marker in Hemodialysis

Hasuike

Nakanishi²,

Maeda³

et al. 2002

Nephron

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Carbamylation requires isocyanic acid derived from urea. Carbamylation of hemoglobin (Hb) produces carbamylated Hb (carbHb), which could serve as a marker of posttranslational protein modification possibly associated with such uremic complications as atherosclerosis. Since relative carbHb levels are determined by mean urea concentration and duration of exposure, they could be used to assess the adequacy of a patient’s hemodialysis (HD) regimen. We therefore determined the relationship between carbHb and urea kinetics in patients with chronic renal failure (CRF) undergoing maintenance HD. In pre-HD determinations as well as in nondialyzed subjects including healthy subjects and CRF patients without dialysis, carbHb correlated well with blood urea nitrogen (BUN) concentrations, especially with BUN averaged for the preceding 1–3 months. In HD patients, carbHb correlated significantly with urea kinetics (time-averaged concentration of urea, or TAC_urea, K_t/V and urea reduction rate). The estimated mean urea concentration in HD patients calculated from the relationship between carbHb and averaged BUN over 3 months in the nondialyzed groups was lower than TAC_urea, suggesting that TAC_urea may be an overestimate. Pre-HD BUN is not a good nutritional index since detrimental decreases in urea elimination from the body can elevate pre-HD BUN independently of nutrition. We therefore devised a new nutritional index, BUN/carbHb, which correlated significantly with serum albumin as well as the normalized protein catabolic rate. These results demonstrate that carbHb accurately reflects uremic control and the BUN/carbHb ratio could serve as an index of nutritional state in HD patients.

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Section: Discussionsupporting

confidence: 79%

Carbamylated Hemoglobin as a Therapeutic Marker in Hemodialysis

Hasuike

Nakanishi²,

Maeda³

et al. 2002

Nephron

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“…Therefore, the rate of isocyanate production may be too low at 38°C and, thus, insufficient for converting AMK to MQA. Since urea does carbamoylate free amino groups in vivo [15, 19], the time required for obtaining relevant concentrations of isocyanate may be decisive. That what is possible in vivo over extended periods of time may be not attained within a few hours of incubation.…”

Section: Discussionmentioning

confidence: 99%

“…Both urea and carbamoyl phosphate are known to cause non‐enzymatic N ‐carbamoylation of free amino groups under physiological conditions, phenomena which have been particularly studied in sickle cell anemia. In this disease, carbamoylation of the N‐terminal valine of the β‐chain, followed by release of the modified amino acid as valine hydantoine, has received some attention, because it attenuates the symptoms and favors the lifetime of erythrocytes [15–19]. The effect of urea is caused by spontaneous decomposition to isocyanate, which represents the carbamoylating agent [18, 19].…”

Section: Introductionmentioning

confidence: 99%

“…In this disease, carbamoylation of the N‐terminal valine of the β‐chain, followed by release of the modified amino acid as valine hydantoine, has received some attention, because it attenuates the symptoms and favors the lifetime of erythrocytes [15–19]. The effect of urea is caused by spontaneous decomposition to isocyanate, which represents the carbamoylating agent [18, 19]. Carbamoyl phosphate can likewise generate this compound [20] and has been used to carbamoylate proteins, not only hemoglobin, but also carbonic anhydratase [21], other blood and brain proteins [20].…”

Section: Introductionmentioning

confidence: 99%

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Reactions of the melatonin metabolite N¹‐acetyl‐5‐methoxykynuramine with carbamoyl phosphate and related compounds

Kuesel

Hardeland

Pfoertner

et al. 2009

Journal of Pineal Research

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N-[2-(6-methoxyquinazolin-4-yl)-ethyl] acetamide (MQA) is a compound formed from the melatonin metabolite N(1)-acetyl-5-methoxykynuramine (AMK). We followed MQA production in reaction systems containing various putative reaction partners, in the absence and presence of hydrogen peroxide and/or copper(II). Although MQA may be formally described as a condensation product of either N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK) with ammonia, or AMK with formamide, none of these combinations led to substantial quantities of MQA. However, MQA formation was observed in mixtures containing AMK, hydrogen peroxide, hydrogen carbonate and ammonia, or AMK, hydrogen peroxide, copper(II) and potentially carbamoylating agents, such as potassium cyanate or, more efficiently, carbamoyl phosphate. In the presence of hydrogen peroxide, copper(II) and carbamoyl phosphate, MQA was the major product obtained from AMK, but the omission of copper(II) mainly led to another metabolite, 3-acetamidomethyl-6-methoxycinnolinone (AMMC). This was caused by nitric oxide (NO) generated under oxidative conditions from carbamoyl phosphate, as shown by an NO spin trap. MQA formation with carbamoyl phosphate was not due to the possible decomposition product, formamide. The reaction of AMK with carbamoyl phosphate under oxidative conditions, in which inorganic phosphate and water are released and which differs from the typical process of carbamoylation via isocyanate, may be considered as a new physiological route of MQA formation.

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“…Le pourcentage d'hé moglobine carbamylé e est effectivement corré lé aux concentrations d'uré e [55], et reflè te la qualité d'é puration de l'uré e en dialyse puisque les concentrations sont plus basses chez des patients ayant un Kt/V plus é levé [56]. L'utilisation de l'hé moglobine carbamylé e a é galement é té proposé e par notre groupe pour distinguer l'insuffisance ré nale aiguë de l'IRC [57].…”

Section: Proté Ines Carbamylé Es Comme Biomarqueursunclassified

Rôle de la carbamylation des protéines dans les complications de l’insuffisance rénale chronique

Gillery

Jaisson

Gorisse

et al. 2015

Néphrologie & Thérapeutique

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Carbamylated haemoglobin—a retrospective index of time-averaged urea concentration

Cited by 15 publications

References 0 publications

Carbamylated Hemoglobin as a Therapeutic Marker in Hemodialysis

Carbamylated Hemoglobin as a Therapeutic Marker in Hemodialysis

Reactions of the melatonin metabolite N¹‐acetyl‐5‐methoxykynuramine with carbamoyl phosphate and related compounds

Rôle de la carbamylation des protéines dans les complications de l’insuffisance rénale chronique

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Carbamylated haemoglobin—a retrospective index of time-averaged urea concentration

Cited by 15 publications

References 0 publications

Carbamylated Hemoglobin as a Therapeutic Marker in Hemodialysis

Carbamylated Hemoglobin as a Therapeutic Marker in Hemodialysis

Reactions of the melatonin metabolite N1‐acetyl‐5‐methoxykynuramine with carbamoyl phosphate and related compounds

Rôle de la carbamylation des protéines dans les complications de l’insuffisance rénale chronique

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Reactions of the melatonin metabolite N¹‐acetyl‐5‐methoxykynuramine with carbamoyl phosphate and related compounds