Bilirubin-albumin binding affinity and serum albumin concentration during intensive phototherapy (blue double light) in jaundiced newborn infants

Ebbesen, Finn; Jacobsen, Jørgen

doi:10.1007/bf00441483

Cited by 17 publications

(11 citation statements)

References 16 publications

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“…Bilirubin undergoes a number of photochemical reactions in vitro and in vivo, all of which yield photoisomers that are more polar than the native molecule (Onishi et al, 1986). Many previous studies (Onishi, 1973;Cashore et al, 1975;Ogawa et al, 1976;Ebbesen & Jacobsen, 1980;Ahlfors et al, 1982;Berde et al, 1984;Gartner et al, 1985) have already shown that phototherapy does not lead to any apparent detrimental effect on albumin binding of bilirubin and, furthermore, the expected increase in albumin binding capacity for bilirubin and the expected decreases in unbound bilirubin in response to decreases in serum bilirubin concentration occurred. However, it was usually observed that, for a few hours after the initiation of phototherapy, the total bilirubin concentration does not decrease but rather increases and that the geometric-photoisomer concentrations increase significantly.…”

Section: Introductionmentioning

confidence: 89%

The effect of bilirubin photoisomers on unbound-bilirubin concentrations estimated by the peroxidase method

Itoh¹,

Yamakawa²,

Onishi³

et al. 1986

Biochemical Journal

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Unbound bilirubin is oxidized to nearly colourless substances in the presence of H2O2 or ethyl hydroperoxide and horseradish peroxidase. To predict the risk of kernicterus (degenerated yellow pigmentation of nerve cells), this principle has been widely utilized for estimating the concentration of unbound bilirubin in hyperbilirubinaemic serum. However, the serum contains polar geometric photoisomers of bilirubin. Therefore, to clarify the effect of bilirubin photoisomer concentrations on unbound-bilirubin concentration, the concentration of bilirubin and its photoisomer and of unbound bilirubin in samples obtained from experiments in vivo and in vitro were simultaneously and individually estimated by h.p.l.c. and the peroxidase method. During photoirradiation, both in vivo and in vitro, the serum polar (ZE)-bilirubin IX alpha concentration increased remarkably, but unbound-bilirubin values were not affected at all. However, during experiments in vitro, unbound bilirubin concentrations increased only when concentrations of the rather polar (EZ)- and (EE)-cyclobilirubin IX alpha increased considerably in a human serum albumin-bilirubin solution irradiated with blue light. Thus it is concluded that unbound-bilirubin concentrations, and consequently the initial rate of the peroxidase reaction, is not accelerated by the increase in either (ZE)-bilirubin or (EZ)-cyclobilirubin concentration within the clinically observed range.

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Section: Introductionmentioning

confidence: 89%

The effect of bilirubin photoisomers on unbound-bilirubin concentrations estimated by the peroxidase method

Itoh¹,

Yamakawa²,

Onishi³

et al. 1986

Biochemical Journal

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“…As observed in a previous study (9) a slight decrease of the serum albumin concentration occurred during double light treatment. Possible explanations of this finding are discussed in this paper (9).…”

Section: Discussionmentioning

confidence: 71%

“…Double light treatment (6,10,26) is used in severe hyperbilirubinaemia. During ordinary phototherapy the serum bilirubin concentration is reduced and it is further reduced during double light treatment (6,8,9,10). Clinical investigations (12,20) have shown that besides being dependent on the serum unconjugated bilirubin concentration, the risk of bilirubin encephalopathy also depends upon the serum reserve albumin concentration for binding of bilirubin (reserve albumin = albumin with vacant primary sites for binding of bilirubin), i.e.…”

mentioning

confidence: 99%

BILIRUBIN, RESERVE ALBUMIN FOR BINDING OF BILIRUBIN AND pH IN PLASMA DURING PHOTOTHERAPY (ORDINARY AND DOUBLE LIGHT) OF TERM NEWBORN INFANTS

Ebbesen

1981

Acta Paediatrica

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Forty-five term newborn infants with uncomplicated hyperbilirubinaemia were treated continuously with phototherapy for 24 hours. Twenty-eight infants received double light treatment and 17 infants ordinary phototherapy. During both treatments a significant decrease in the serum unconjugated bilirubin concentration, a significant increase in the serum reserve albumin concentration for binding of bilirubin determined by the [14C] MADDS method, and a significant decrease in the index of serum bilirubin toxicity occurred. The changes in these parameters were significantly greater during the double light treatment than during the ordinary phototherapy. During the treatment the fall in index was constant. No significant change in plasma pH was seen. Thus, the study gives further evidence that the risk of bilirubin encephalopathy is reduced by phototherapy and that double light treatment is in the respect superior to ordinary phototherapy. Prior to phototherapy the molar ratio in serum of unconjugated bilirubin plus reserved albumin for binding of bilirubin to albumin was only 0.60, on average, and during the treatment the increase in the serum reserve albumin concentration was less than the decrease in the serum bilirubin concentration. This can be explained either by the presence in infant serum of an unknown ligand interfering competitively or allosterically in the binding of MADDS and bilirubin to albumin, or by the existence of a foetal albumin with a lower affinity for MADDS than adult albumin.

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“…A free bilirubin concentration of 20nM (50nM at 370C) is the limit of developing bilirubin encephalopathies, provisionally suggested by Wennberg et al (1976). No doubt, however, a drastic decrease of the apparent concentration of unbound bilirubin takes place during phototherapy in newborn infants with liver excretion operating well (Ebbesen, 1981;Ebbesen & Jacobsen, 1980). Being more loosely bound to albumin as compared with bilirubin (Table 1), photobilirubin may disturb the measurements of free bilirubin used to determine the risk of bilirubin encephalopathies in neonatal hyperbilirubinaemia.…”

Section: Discussionmentioning

confidence: 99%

Albumin binding of photobilirubin II

Meisel¹,

Biebler²,

Gens³

et al. 1983

Biochemical Journal

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Photobilirubin II, a stereoisomer of bilirubin, binds to human serum albumin at a single binding site (K = 2.2 x 10(6)M-1), presumably the high-affinity bilirubin-binding site. Binding in the secondary (class II) binding sites is of minor importance. The results are discussed with respect to photometabolism of bilirubin and as a possible source of error in the determination of bilirubin unbound to albumin.

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Bilirubin-albumin binding affinity and serum albumin concentration during intensive phototherapy (blue double light) in jaundiced newborn infants

Cited by 17 publications

References 16 publications

The effect of bilirubin photoisomers on unbound-bilirubin concentrations estimated by the peroxidase method

The effect of bilirubin photoisomers on unbound-bilirubin concentrations estimated by the peroxidase method

BILIRUBIN, RESERVE ALBUMIN FOR BINDING OF BILIRUBIN AND pH IN PLASMA DURING PHOTOTHERAPY (ORDINARY AND DOUBLE LIGHT) OF TERM NEWBORN INFANTS

Albumin binding of photobilirubin II

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