Ammonia Nitrogen, Urea and Uric Acid Blood Levels in Normal and Hypodystrophic Newborns

Rubaltelli, F. F.; Formentin, P A; Tatò, Luciano

doi:10.1159/000240219

Cited by 11 publications

(6 citation statements)

References 4 publications

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“…However, none of the infants in the present study suffered from anoxia or asphyxia. In full-term infants, dysmaturity is associated with a higher plasma ammonia concentration but also with a higher blood urea nitrogen concentration [11], This was not found in the present study but the infants were all premature. In addi tion, only 4 small-for-date infants were hypo glycemic (< 3 6 mg/dl).…”

Section: Commentscontrasting

confidence: 75%

Hyperammonemia in Hypoglycemic Preterm Neonates

Sann¹,

Dellamonica²

1983

Neonatology

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Plasma glucose, blood urea nitrogen, and ammonia were measured simultaneously in 44 newborns a few hours after birth. When the concentration of plasma glucose was below 30 mg/dl, plasma ammonia concentration was significantly higher (129 ± 67 μmol/l) than in normoglycemic infants (74 ± 33 μmol/l; p < 0.01). Blood urea nitrogen was slightly lower in hypoglycemic infants (3.65 ± 0.7 mmol/l) than in the control group (4.5 ± 1 mmol/l) but the difference was not significant. These data show that hyperammonemia can be associated to hypoglycemia in low birth weight infants. Therefore, further investigations are required to determine the link between urea and glucose production rates in hypoglycemic newborns and whether hyperammonemia participates in the deleterious effects of hypoglycemia on the neonatal brain.

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Section: Commentscontrasting

confidence: 75%

Hyperammonemia in Hypoglycemic Preterm Neonates

Sann¹,

Dellamonica²

1983

Neonatology

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“…This is likely due to differences in procedures for collecting and preserving specimens, types of laboratory tests and in the blood sampled, that is, venous, arterial or capillary. 36 The measurement of plasma ammonia concentration is greatly influenced by both pre-analytical and analytic delays after collection, which may lead to falsely high results. 37,38 In particular, ammonia concentration increases spontaneously in blood after collection and is stable for <15 min at 4°C.…”

Section: Discussionmentioning

confidence: 99%

Plasma ammonia concentrations in extremely low birthweight infants in the first week after birth: secondary analysis from the ProVIDe randomized clinical trial

et al. 2020

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BACKGROUND: Little is known about normative ammonia concentrations in extremely low birthweight (ELBW) babies and whether these vary with birth characteristics. We aimed to determine ammonia concentrations in ELBW babies in the first week after birth and relationships with neonatal characteristics and protein intake. METHODS: Arterial blood samples for the measurement of plasma ammonia concentration were collected within 7 days of birth from ProVIDe trial participants in six New Zealand neonatal intensive care units. RESULTS: Three hundred and twenty-two babies were included. Median (range) gestational age was 25.7 (22.7-31.6) weeks. Median (interquartile range (IQR)) ammonia concentration was 102 (80-131) µg/dL. There were no statistically significant associations between ammonia concentrations and birthweight or sex. Ammonia concentrations were weakly correlated with mean total (Spearman's r s = 0.11, P = 0.047) and intravenous (r s = 0.13, P = 0.02) protein intake from birth, gestational age at birth (r s = −0.13, P = 0.02) and postnatal age (r s = −0.13, P = 0.02). CONCLUSIONS: Plasma ammonia concentrations in ELBW babies are similar to those of larger and more mature babies and only weakly correlated with protein intake. Currently, recommended thresholds for investigation of hyperammonaemia are appropriate for ELBW babies. Protein intake should not be limited by concerns about potential hyperammonaemia.

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“…Rubaltelli (25), using a cation-exchange method, found that full term S G A infants, less than 5 days of age, had higher plasma ammonium levels (48 +-1 0 p M ) than did full term A G A infants (35 + 5 pM). Raiha et al (22) found plasma ammonium levels of low birthweight infants less than 6 weeks of age to vary between 60-90 p M when measured with an ammonium electrode.…”

Section: Plasma Ammonium Levels In Neonatesmentioning

confidence: 98%

Asymptomatic Hyperammonemia in Low Birthweight Infants

1978

Pediatr Res

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SummaryAt 0-3 days of age the plasma ammonium concentration in full term appropriate for gestational age (AGA) infants was (mean 2 SEM) 27.5 & 0.5 pM; a value similarlo that reported * in adults. Ammonium levels in low birthweight AGA and SGA groups were 47.0 + 2.0 p M and 45.1 r 3.3 p M respectively; significantly elevated (P < 0.001) as compared to the full term group. These increased ammonium levels persisted at 3-5 weeks of age. Associated with the hyperammonemia was a significant (P < 0.01) decrease in plasma a-ketoglutarate concentration:11.8 r 1.0 pM, in the low birthweight AGA as compared to 20.7 r 0.6 p M in the full term AGA infants. There was an inverse linear correlation between ~l a s m a concentrations of ammonium and a-ketoglutarate r = -0.86, P < 0.001. Urinary orotate excretion was significantly elevated (P < 0.05) in low birthweight AGA infants. There was no difference in the plasma concentrations of glutamine, glutamate, or alanine among the various groups. Hyperammonemia was not associated with neurologic dysfunction. SpeculationThere is a greater accumulation of ammonium in low birthweight as compared to full term infants. This may be a consequence of a developmental delay of one or more of the enzymes required for urea synthesis. Alternatively, the hyperammonemia may be related to arginine andlor ornithine diversion out of the cycle and incomplete repletion of ornithine from glutamate via the A'-pyrroline-5-carboxylate pathway.were measured once or twice a week on capillary blood during the first 2 months of life. Plasma a-ketoglutarate concentration and urinary orotate excretion were also measured at 0-3 days of age in 30 infants. Plasma ammonium determinations were performed within 30 min of blood drawing using a cation exchange resin, AS previobsly described (3). The normal adult range is 15-33 pM. Glutamine (18), glutamate (4), alanine (30), and a-ketoglutarate (16) were measured by modifications of enzymatic fluorometric techniques, allowing capillary plasma to be used. Urinary orotate was measured by the method of Goldstein et al. (11). A neurologic examination as described by Prechtl and Beintema (20) was performed on the low birthweight infants at 0-3 days of age. RESULTSThe full term group consisted of 25 males (22 were black) and 27 females (25 were black); the low birthweight groups consisted of 14 males (11 were black) and 22 females (20 were black).Birthweights of the groups were (mean + SEM): full term 3261 + 59 g, low birthweight SGA 1848 + 185 g, and low birthweight AGA 1963 + 79 g. Gestational age in the groups were (mean + SD): full term AGA 39 + 1.5 weeks, low birthweight SGA 37 + 3 weeks and low birthweight AGA 33 + 2.5 weeks. All infants received a proprietary milk formula (Similac) containing 1.5 g protein/100 ml, 18 parts bovine whey protein to 82 parts bovine caseins. Mean protein intake was similar in all groups at 3-5 weeks of age (3.0 g/kg/day) and was higher in the full term group during the first 3 days of life (1.7 compared to 1.2 &kg/ day). At 0-3 days of age,...

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Ammonia Nitrogen, Urea and Uric Acid Blood Levels in Normal and Hypodystrophic Newborns

Cited by 11 publications

References 4 publications

Hyperammonemia in Hypoglycemic Preterm Neonates

Hyperammonemia in Hypoglycemic Preterm Neonates

Plasma ammonia concentrations in extremely low birthweight infants in the first week after birth: secondary analysis from the ProVIDe randomized clinical trial

Asymptomatic Hyperammonemia in Low Birthweight Infants

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