Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Allantoin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed2006

Increased plasma homocysteine and allantoin levels in coronary artery disease: possible link between homocysteine and uric acid oxidation.

OBJECTIVE: Homocysteine increases the damage to the cardiovascular system in different ways, one of them is the formation of reactive oxygen species resulting from the auto-oxidation of homocysteine. At the same time, uric acid is one of the major antioxidants in the plasma and protects the cells towards increased ROS activity. In humans, allantoin is only formed from non-enzymatic oxidation of uric acid by free radicals. We aimed to determine the levels of homocysteine, uric acid and allontoin in patients with coronary artery diseases, and to evaluate the possible correlation between homocysteine and allantoin. METHODS AND RESULTS: Plasma total homocysteine, uric acid and allantoin levels of 50 patients with coronary artery diseases and 23 healthy controls were determined by HPLC methods. Commercial diagnostic kits were used for the determination of other biochemical parameters. We obtained higher homocysteine, uric acid and allantoin levels in patients than in controls (p < 0.0001). Homocysteine levels were positively correlated with uric acid (r = 0.435, p < 0.0001) and allantoin (r = 0.583, p < 0.0001) levels in the whole study population. This correlation was persistent between allantoin and homocysteine after adjustment of these parameters for age, sex and creatinine. We accepted 15.0 micromol/l as a cut-off value between normal and mildly elevated homocysteine levels for patients and controls. Twenty-five patients showed moderate hyperhomocysteinaemia. The mean allantoin and uric acid values of the moderate hyperhomocysteinaemic group were significantly higher than that of the group having lower homocysteine levels than this cut-off value (p < 0.0001 for allantoin, p < 0.02 for uric acid). CONCLUSION: Results imply that there is increased allantoin production resulting from uric acid oxidation by free radicals in hyperhomocysteinaemic patients with coronary artery disease. The possible significance of the relationship between homocysteine and allantoin warrants further study.

Adult↗
PubMed1996

[Plasma allantoin in patients undergoing maintenance hemodialysis].

Recently, it has been noted that radical molecules participate in the pathogenesis of some of the complications associated with long-term dialysis therapy, such as amyloidosis. Since allantoin is produced from uric acid almost exclusively by the hydroxy radical, we investigated the plasma concentrations of allantoin in 71 patients with chronic renal failure who were on maintenance hemodialysis. Our specific objective was to investigate the relation of allantoin to the plasma concentrations of beta2-microglobulin and methylguanidine to evaluate the potential of allantoin as a significant parameter of the radical reaction. Although plasma allantoin was not detected in 15 healthy controls, plasma concentrations of allantoin increased markedly in all of the hemodialysis patients (42.6 +/- 37.7 nmol/mL) and wide variation was observed from 4.3 to 185.2 nmol/mL. In addition, we confirmed significant correlations between plasma concentrations of allantoin and beta2-microglobulin as well as serum concentrations of methylguanidine/creatinine and hyaluronic acid (r - 0.456, p < 0.0005, r = 0.313, p < 0.005, r = 0.368, p < 0.01, respectively). Although evidence for a direct link between plasma allantoin levels and amyloidosis was not obtained, the increase in the plasma concentrations of allantoin suggested its clinical significance as a parameter of the radical reaction that is thought to participate closely in the pathogenesis of dialysis-related amyloidosis. From a practical point of view, the measurement of plasma allantoin can be expected to become a significant method of measuring radical members which may be useful in the prophylaxis of some of the complications induced by free radicals.

Adolescent↗
PubMed2003

Factors affecting application of milk allantoin as an estimator of microbial protein flow to the duodenum under commercial conditions.

Three experiments were conducted to determine the effect of diet change, milk sampling technique, and bovine somatotropin (bST) on allantoin output in milk and the use of allantoin as a practical, noninvasive method for estimating microbial protein flow in dairy cattle. In experiment 1, four lactating Holstein cows were used in a 2 x 2 Latin square design with two treatments (ratio of forage to concentrate) and two periods. In experiment 2, six Holstein cows were used in a completely randomized design, and milk was collected by 1) a strip sample collected immediately before milking, 2) a strip sample collected 3 min from start of milking, and 3) a composite sample taken with an autosampler. In experiment three, 10 cows were used in a randomized block design to determine the effect of bST on milk allantoin. Milk samples were taken daily for 21 d, 7 d before, and 14 d after bST administration. In experiment 1, allantoin output (mmol/d) was significantly greater for cows fed the higher ratio of concentrate to forage, and there was a significant change in the amount of allantoin in milk 12 h (first subsequent milking) after a diet change. There was no difference in milk yield or dry matter intake between treatments. In experiment 2, no difference was detected in milk allantoin concentration among the three sampling methods. In experiment 3, milk yield, allantoin concentration, and total allantoin output was significantly increased after bST administration even though dry matter intake (DMI) remained unchanged. During the first 14 d following bST administration, estimates of microbial protein production derived from milk allantoin may be inaccurate due to increased milk production without an increase in DMI.

Allantoin↗
PubMedDate not supplied

Identification of allantoin, uric acid, and indoxyl sulfate as biochemical indicators of filth in food packaging by LC.

A liquid chromatographic (LC) method was developed for the determination of allantoin, uric acid, and indoxyl sulfate in mammalian urine contaminated packaging material including paper bagging, corrugated cardboard, grayboard, and burlap bagging. The procedure involves solvent extraction and isolation of the 3 analytes by reversed-phase LC with ultraviolet detection at 225 nm for allantoin and 286 nm for uric acid and indoxyl sulfate. The composition of authentic mammalian urine such as mouse, rat, cat, dog, and human were also determined with regard to the 3 compounds of interest. A linear concentration range of 0.11-20.4, 0.02-10.0, and 0.04-30.0 microg/mL was obtained for allantoin, uric acid, and indoxyl sulfate, respectively. Limits of detection (LOD) and quantitation (LOQ) were 0.0104 and 0.0345 microg/mL for allantoin; 0.0018 and 0.0060 microg/mL for uric acid; and 0.0049 and 0.0165 microg/mL for indoxyl sulfate, respectively. Interday relative standard deviation values for a mixture of standard allantoin, uric acid, and indoxyl sulfate (n = 5) were 0.97, 0.80, and 0.94%, respectively. Analyte composition for 5 types of authentic mammalian urine varied from 0.19-6.88 mg/mL allantoin; 0.08-0.57 mg/mL uric acid; and 0.03-0.78 mg/mL indoxyl sulfate. Analyte content for 8 samples including 2 samples each for paper, cardboard, grayboard, and burlap bagging each contaminated with mouse or rat urine ranged from <LOD to 4,598 microg/gm allantoin; <LOD to 202 microg/gm uric acid; and 17.5 to 616 microg/gm indoxyl sulfate. Recoveries of allantoin, uric acid, and indoxyl sulfate from 11 fortified samples (4 types) for both mouse and rat urine ranged from 28.2 to 114.1 % for allantoin; 32.6 to 123.4% for uric acid; and 52.6 to 118.2% for indoxyl sulfate.

Allantoin↗
PubMed1975

Handling of allantoin by the rat kidney. Clearance and micropuncture data.

Renal excretion of allantoin was measured by tracer techniques. After injection of 2-C14 urate and H3 inulin, clearances of allantoin and inulin were measured and both proximal and distal tubules were micropunctured. In confirmation of earlier results 2-C14 urate injected into an intact animal is very rapidly converted to C14 allantoin: after 15 min more than 90% of urinary tracer is present as allantoin. It was further observed that 1) allantoin clearance is essentially identical with inulin clearance over a wide range of urine flows; 2) no net transport of allantoin occurs in either proximal or distal tubules. Clearly allantoin is handled by the rat kidney like inulin. The total excretion of filtered allantoin unlike that of filtered urate provides an easy and effective mechanisms for animals possessing the enzyme uricase to dispose of their purine loads.

Allantoin↗
PubMed2006

The relationship between uric acid and its oxidative product allantoin: a potential indicator for the evaluation of oxidative stress in birds.

Uric acid is the main nitrogenous waste product in birds but it is also known to be a potent antioxidant. Hominoid primates and birds lack the enzyme urate oxidase, which oxidizes uric acid to allantoin. Consequently, the presence of allantoin in their plasma results from non-enzymatic oxidation. In humans, the allantoin to uric acid ratio in plasma increases during oxidative stress, thus this ratio has been suggested to be an in vivo marker for oxidative stress in humans. We measured the concentrations of uric acid and allantoin in the plasma and ureteral urine of white-crowned sparrows (Zonotrichia leucophrys gambelii) at rest, immediately after 30 min of exercise in a hop/hover wheel, and after 1 h of recovery. The plasma allantoin concentration and the allantoin to uric acid ratio did not increase during exercise but we found a positive relationship between the concentrations of uric acid and allantoin in the plasma and in the ureteral urine in the three activity phases. In the plasma, the slope of the regression describing the above positive relationships was significantly higher immediately after activity. We suggest that the slope indicates the rate of uric acid oxidation and that during activity this rate increases as a result of higher production of free radicals. The present study demonstrates that allantoin is present in the plasma and in the ureteral urine of white-crowned sparrows and therefore might be useful as an indicator of oxidative stress in birds.

Allantoin↗
PubMed2002

Assay of serum allantoin in humans by gas chromatography-mass spectrometry.

BACKGROUND: The small amount of allantoin present in human serum results from free radical (FR) action on urate and may provide a stable marker of free radical activity in vivo. We describe a gas chromatography-mass spectrometry (GC-MS) assay for serum allantoin and report a reference range in healthy individuals. METHODS: Fasting blood samples were obtained from 134 healthy middle-aged volunteers (56 men, mean age 55, range 45-72; 78 women, mean age 55, range 50-72) Allantoin was assayed using 15N(2) allantoin as an internal standard. After isolation from aqueous standards or serum by extraction onto an anion exchange column (AG-MP1), allantoin was derivatised with N-methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA). Derivatives were injected onto an HP-1 column and analysed using a Mass Selective Detector with Single Ion Monitoring at 398 and 400 m/z. RESULTS: The distribution of serum allantoin concentrations in men and women was non-Gaussian and log transformation was used for the analysis of data. Women (10.8 +/- 1.7 micromol/l (mean +/- S.D.)) had significantly lower serum allantoin levels than men (13.4 +/- 1.6 micromol/l, p=0.015). Reference ranges (95% CI) for middle-aged healthy subjects were 7.4-46.8 micromol/l (men) and 3.7-31.2 micromol/l (women). CONCLUSION: Gas chromatography-mass spectrometry provides a reliable and accurate method for the determination of serum allantoin.

Aged↗
PubMed2001

Purine nucleotide catabolism in rat liver: labelling of uric acid and allantoin after treatment with oxonic acid and allopurinol.

In our previous experiments on rat liver we found that 15' after intraperitoneal administration of 14C-formate the specific radioactivity of allantoin was always higher than that of uric acid. The present experiments have been carried out to interpret this unexpected result, which was only observed in liver and we studied: a) the incorporation of 14C-glycine into uric acid and allantoin; b) the effects of two competitive inhibitors of xanthine oxidase and uricase, oxonic acid and allopurinol respectively, on levels of uric acid and allantoin in liver and on their specific radioactivity after administration of labelled precursor. The results suggested: a) that under normal conditions, the formation of allantoin is so fast that it exceedes export from liver to serum, and thus the radioactivity of labelled precursors accumulates in allantoin; b) that when allopurinol or oxonic acid are administered, the rate of export exceeds that of allantoin formation and the incorporation of radioactivity into allantoin is lower; c) that not all the data, however, could be interpreted on this basis, but seems to require the existence of different pools of uric acid, which are transformed separately into allantoin.

Allantoin↗
PubMed1998

Allantoin and allantoic acid titre in the faeces and tissues of the developing larva of the moth, Orthaga exvinacea Hampson.

Allantoin and allantoic acid are investigated in the faeces and tissues of the developing sixth instar larva of the moth, Orthaga exvinacea. The nitrogen excreted as allantoin and allantoic acid is compared with nitrogen excreted as uric acid and ammonia. The larva excretes 2.35-5.14 mumol/g allantoin and 0.74-1.34 mumol/g allantoic acid which account for 0.83 to 2.39% and 0.23 to 0.53%, respectively, of the excreted total nitrogen. Allantoin and allantoic acid are found to be minor nitrogenous end-products of the larva. Allantoin and allantoic acid are also present in the haemolymph and fat body of the larva in varying concentrations. The level of allantoin in the haemolymph shows a negative correlation with the allantoin concentration of faeces and fat body. The allantoin is found to be stored in the fat body at a low level. The results of the present study also indicate the coexistence of uric acid storage and uricolysis.

Allantoin↗
PubMed2000

Is allantoin in serum and urine a useful indicator of exercise-induced oxidative stress in humans?

To assess whether allantoin levels in serum and urine are influenced by exhaustive and moderate exercise and whether allantoin is a useful indicator of exercise-induced oxidative stress in humans, we made subjects perform exhaustive and moderate (100% and 40% VO2max) cycling exercise and examined the levels of allantoin, thiobarbituric acid reactive substances (TBARS) and urate in serum and urine. Immediately after exercise at 100% VO2max, the serum allantoin/urate ratio was significantly elevated compared with the resting levels while the serum urate levels was significantly elevated 30 min after exercise. The serum TBARS levels did not increase significantly compared with the resting levels. Urinary allantoin excretion significantly increased during 60 min of recovery after exercise, however, urinary urate excretion decreased significantly during the same period. The urinary allantoin/urate ratio also rapidly increased during 60 min of recovery after exercise. Urinary TBARS excretion decreased during the first 60 min of the recovery period and thereafter significantly increased during the latter half of the recovery period. On the contrary, after 40% VO2max of exercise, no significant changes in the levels of urate, allantoin and TBARS in serum or urine were observed. These findings suggest that allantoin levels in serum and urine may reflect the extent of oxidative stress in vivo and that the allantoin which appeared following exercise may have originated not from urate formed as a result of exercise but from urate that previously existed in the body. Furthermore, these findings support the view that allantoin in serum and urine is a more sensitive and reliable indicator of in vivo oxidative stress than lipid peroxidation products measured as TBARS.

Adult↗
PubMed1980

Renal handling of [14C]allantoin in the rabbit.

Rabbit renal cortical slices were incubated at 25 degrees C, pH 7.4, for 2 hr under 100% O2 in a phosphate-buffered medium. [14C]allantoin was accumulated to a tissue water/medium ratio of 1.38 +/- 0.03 (mean +/- S.E., n = 22). Under 100% N2, the tissue water/medium ratio fell significantly to 0.90 +/- 0.02 (n = 14, P less than .001). Probenecid (an anion) inhibited the uptake of allantoin at doses which had no effect on the water content of the slices, i.e., did not appear to have a toxic effect on the tissue. Its effect was specific. In contrast, salicylate (another anion) and quinine (a cation) inhibited the uptake of allantoin only at concentrations which simultaneously increased the water content of the slices. These results suggest a toxic effect on cell metabolism. Salicylate (an anion) and quinine (a cation), in dosage which inhibited allantoin uptake, also inhibit the uptake of the para-aminohippuric acid (an anion) and tetraethylammonium bromide (a cation). Net secretion of allantoin was observed in urinary clearance experiments on anesthetized rabbits acutely loaded with allantoin, under mannitol diuresis. At flow rates less than 1 ml/kg.min, fractional excretion of [14C]allantoin was 0.85 +/- 0.03 (n = 27 clearance periods) indicating significant net reabsorption. When urine flow was increased above 1 ml/kg.min, fractional excretion of [14C]allantoin reached 1.07 +/- 0.03 (n = 18 clearance periods), i.e., net secretion.

Allantoin↗
PubMed2006

Enzymatic assay of allantoin in serum using allantoinase and allantoate amidohydrolase.

A new enzymatic assay for specifically measuring allantoin concentration in serum has been developed. The currently used methods for allantoin analysis are time consuming and nonspecific or depend on the use of expensive equipment. In our method, allantoin is converted to allantoate by the action of allantoinase (EC 3.5.2.5). The allantoate produced is hydrolyzed to ureidoglycine and ammonia by the action of allantoate amidohydrolase (EC 3.5.3.9). Nicotinamide adenine dinucleotide phosphate-dependent glutamate dehydrogenase (EC 1.4.1.4) subsequently acts on the ammonia produced, resulting in a change in absorbance at 340nm due to the consumption of reduced nicotinamide adenine dinucleotide phosphate. The amount of allantoin present is related to the change in the absorbance. The standard curve is linear up to at least 1mM allantoin. The procedure is simple, rapid, and accurate. The method has been used to measure serum allantoin levels after oral administration of purine nucleotides to experimental animals, including rats that have uricase catalyzing the conversion of urate to allantoin.

Allantoin↗
PubMed2005

Monitoring of antioxidant properties of uric acid in humans for a consideration measuring of levels of allantoin in plasma by liquid chromatography.

Uric acid is the end product of purine metabolism in humans. It has been pointed out that uric acid acts as an antioxidant and is capable to react with biologically relevant oxidants to form allantoin. Therefore, measurement of allantoin in humans was proposed as a marker of oxidative stress. We estimated allantoin in human plasma obtained from the patients with chronic renal failure before hemodialysis (n=30), patients with non-insulin dependent diabetes mellitus (n=30) and blood donors (n=30) using a method based on selective isolation of allantoin from deproteinized plasma samples on AG 1-X8 resin and its derivatization to glyoxylate-2,4-dinitrophenylhydrazone. The method is free from urate and glyoxylate interferences. Separation of glyoxylate-2,4-dinitrophenylhydrazone from other hydrazones was achieved on reversed phase HPLC with gradient elution and UV/VIS detection at 360 nm. The analytical performance of this method is satisfactory with intra-assay CV 5.7%, inter-assay CV 8.3% and recovery 94.1%. We have determined other parameters of oxidative stress (malondialdehyde, total antioxidant status, superoxide dismutase and glutathione peroxidase) too. The preliminary reference range of allantoin in a group of blood donors is 4.76+/-2.99 micromol/L. In the patients with chronic renal failure and the patients with non-insulin dependent diabetes mellitus we found allantoin levels in plasma (27.1+/-13.8) micromol/L and (11.08+/-5.90) micromol/L, respectively. It seems that allantoin is a possible indicator of free radical damage in vivo.

Allantoin↗
PubMed2004

Oxidation of uric acid in rheumatoid arthritis: is allantoin a marker of oxidative stress?

Free radicals are implicated in many diseases including atherosclerosis, cancer and also in rheumatoid arthritis. Reaction of uric acid with free radicals, such as hydroxyl radical and hypochlorous acid (HOCl) results in allantoin production. In this study, we measured the serum allantoin levels, oxidation products of uric acid, as a marker of free radical generation in rheumatoid arthritis. Fasting blood samples were obtained from 21 rheumatoid patients and 15 healthy controls. In this study, the serum allantoin and uric acid levels were measured by a gas chromatography-mass spectrometry method and the ratios were calculated. The mean allantoin and uric acid levels and ratios in the patient group were 22.1 +/- 11.3, 280.5 +/- 65.0 and 8.0 +/- 3.7 microM, while in the control group they were 13.6 +/- 6.3, 278.3 +/- 53.6 and 4.9 +/- 2.1 microM, respectively. The effects of gender, age, menopausal status, duration of disease and medications on serum allantoin and uric acid levels of the patient and control groups were studied. Our results suggest that uric acid acts as a free radical scavenger and thus is converted to allantoin. Increased allantoin levels suggest the possible involvement of free radicals in rheumatoid arthritis.

Age Factors↗
PubMed1986

[Allantoin excretion of wethers in variations of raw protein and energy administration].

216 values of urinary allantoin excretion were received from 8 digestibility trials, which included 48 rations with different protein and energy content. Thus relations between allantoin excretion and food intake and ration composition, respectively, could be evaluated. Additionally variations in N balance were measured, since there is a close relation to allantoin metabolism. Fecal N excretion was elevated with increasing energy intake, but varied only slightly with modified N supply. Urinary N excretion and also N retention increased with higher N intake. On the other hand urinary N losses were reduced with increasing energy supply and part of the saved nitrogen was deposed into the body. There was a distinct increase in allantoin excretion with raised protein intake, when N supply ranged generally low. But with a daily supply of crude protein above 60 to 70 g there was no significant further response in allantoin excretion. Allantoin excretion increased linearly with higher energy supply. Several restrictions for conclusions on the extent of microbial protein production in the digestive tract estimated out of measured allantoin values were discussed.

Allantoin↗
PubMed1995

The determination of allantoin, a possible indicator of oxidant status, in human plasma.

Because uric acid may be oxidized to allantoin by various reactive oxygen species, it is postulated that uric acid functions as an antioxidant in human bodily fluids. The measurement of allantoin concentrations may therefore be useful for the quantitation of oxidant generation in humans. We develop a reliable assay for the quantitation of human plasma allantoin levels. The method consists of rapid and selective separation of allantoin from uric and glyoxylic acid (which interfere in the assay) using anion-exchange solid-phase extraction prior to conversion of allantoin to glyoxylic acid and derivatization with 2,4-dinitrohenylhydrazine. Determination of glyoxylate-2,4-dinitrophenylhydrazone is achieved by using reversed-phase high-performance liquid chromatography with gradient elution and ultraviolet detection at 360 nm. The analytical performance of the method is satisfactory, with a day-to-day coefficient of variation of 8.9% and a within-batch coefficient of variation of 7.2%. The method is applied to the measurement of allantoin concentrations in the plasma of 99 apparently healthy men, and a preliminary reference range is reported. Clinical studies can now be performed to evaluate allantoin as a possible indicator of free radical damage in vivo.

Allantoin↗
PubMed1991

Renal clearance of plasma allantoin in sheep.

The recovery in urine of an intrajugular infusion of physiological amounts of allantoin was measured in four sheep nourished by an intragastric infusion of volatile fatty acids and casein (to eliminate rumen fermentation). The recovery was 72% (S.E.M. 7) and the remainder was presumed to have been lost by diffusion into the gut and degradation by gut microflora. Measured in two sheep, allantoin was removed from the blood at a fractional rate of 0.30 h-1, and excreted in urine at 0.23 h-1. Calculation based on creatinine excretion showed glomerular filtration rate and tubular reabsorption of allantoin to be unchanged by the intravenous infusion. Maximal tubular reabsorption at 1.28 mmol day-1 was saturated by the load of endogenous allantoin alone. In a second experiment with seven normally fed sheep (28-50 kg live weight, all given 1 kg feed), urinary excretion and plasma concentration of allantoin were linearly related. However, the errors were such that plasma allantoin concentration would be of little value as a predictor of urinary excretion. There was a nearly twofold range in allantoin excretion (the larger animals excreting less), which implied that the supply of microbial biomass to the host animal per unit of feed ingested could be profoundly affected by feeding level.

Allantoin↗
PubMed1977

Renal excretion of allantoin in rats: a micropuncture and clearance study.

Free-flow micropuncture and clearance studies were performed to evaluate the transport of allantoin inthe rat kidney. Inn all studies [2-14C]uric acid and [methoxy-3H]inulin were administered. With a two-step column chromatographic technique, radiolabeled uric acid and allantoin were separated in plasma, urine, and tubular fluid, and the [2-14C]allantoin concentration was determined. Tubular fluid collections were obtained under hydropenic and control coneated animals in the control and volume-expanded states. Clearance data were obtained in oxonic acid-treated animals under the same experimental conditions. These studies indicate that allantoin is not bound to plasma protein and is, therefore, freely filterable. Neither net reabsorption nor net secretion of allantoin was evident along the length of the nephron. The bubular handling of allantoin was demonstrated to be dissociated from that of uric acid in all experimental states. No significant intrarenal production of allantoin from uric acid was observed.

Allantoin↗