THE RELATIONSHIP BETWEEN SERUM BILIRUBIN AND RESERVE ALBUMIN FOR BINDING OF BILIRUBIN DURING PHOTOTHERAPY OF PRETERM INFANTS

ABSTRACT. Ebbesen, F. (Department of Neonatology, Rigshospitalet, Copenhagen, Denmark). The relationship between serum bilirubin and reserve albumin for binding of bilirubin during phototherapy of preterm infants. Acta Paediatr Scand, 70:405, 1981.–Thirty-four preterm newborn infants suffering from uncomplicated hyperbilirubinaemia were studied. The infants received ordinary phototherapy continuously during 48 hours. The serum unconjugated bilirubin concentration decreased significantly during the treatment, and a significant correlation between the changes in the serum bilirubin concentration and the changes in the serum reserve albumin concentration for binding of bilirubin measured by the [¹⁴C]MADDS method was found. The regression coefficients were -0.50 and -0.48 after 24 and 48 hours of treatment, respectively. Thus, it can be concluded that the risk of bilirubin encephalopathy is reduced by phototherapy in preterm infants.     

COMPARISON BETWEEN TWO PREPARATIONS OF HUMAN SERUM ALBUMIN IN TREATMENT OF NEONATAL HYPERBILIRUBINAEMIA

ABSTRACT. Thirty-six newborn infants with normal birth weights and with uncomplicated hyperbilirubinaemia, treated with light, were studied. At onset of phototherapy the infants received intravenously 1 g human serum albumin (HSA) per kg body weight as a 9 % solution. Two different preparations of HSA were used and compared. One of these, HSA_I, contained sodium caprylate and N-acetyltryptophan, 5 mmol/1 of each, as stabilizers. HSA_II contained only caprylate, 5 mmol/1. Nineteen infants received HSA_I and seventeen infants HSA_II. The reserve albumin for binding of bilirubin, measured by the [¹⁴C] MADDS method, was low in both preparations in vitro. During the infusion, the serum concentrations of albumin and reserve albumin increased and the serum unconjugated bilirubin concentration decreased, resulting in a fall in the index of plasma bilirubin toxicity in all infants. After completion of the infusion, the serum concentrations of albumin and reserve albumin declined, and a slight rise in index occurred. The increase in the serum reserve albumin concentration was markedly higher during infusion of HSA_II than of HSA_I. It is concluded that infusion of both HSA preparations during phototherapy provides an immediate protection against bilirubin encephalopathy. HSA_I is inferior to HSA_II, probably due to its content of N-acetyltryptophan.     

EFFECT OF EXCHANGE TRANSFUSION ON SERUM RESERVE ALBUMIN FOR BINDING OF BILIRUBIN AND INDEX OF SERUM BILIRUBIN TOXICITY

ABSTRACT. Ebbesen F. (Department of Neonatology, Rigshospitalet, Copenhagen, Denmark). Effect of exchange transfusion on serum reserve albumin for binding of bilirubin and index of serum bilirubin toxicity. Acta Paediatr Scand, 70:643,.–Seventeen newborn infants, who received their first exchange transfusion due to hyperbilirubinaemia and/or rhesus haemolytic disease, were studied. The exchange transfusions were performed with fresh, citrated blood. During the exchange transfusion a marked increase in the serum reserve albumin concentration for binding of bilirubin measured by the [^,4C]-MADDS method was observed, followed by a smaller decrease after the transfusion. Plasma pH increased both during and after the exchange transfusion. During the exchange transfusion a drastic fall in index of serum bilirubin toxicity was observed, followed by a smaller increase after the transfusion. Citrate was not found to interfere in the binding of bilirubin to albumin. The results are in agreement with the clinical finding that an exchange transfusion performed with fresh, citrated blood effectively reduces the risk of bilirubin encephalopathy. The ratio in serum of binding albumin, i.e. bilirubin plus reserve albumin, to total albumin failed to be increased by the exchange transfusion, and a decrease occurred after the transfusion. These findings indicate the presence in infant serum of non-binding albumin. Donor albumin with intact binding potential is partly transformed into the non-binding variety in the course of one hour after the transfusion. In the most severely rhesus sensitized infant a drastic decline of the serum albumin binding capacity was seen during the first day of life.     

RESERVE ALBUMIN AND BILIRUBIN TOXICITY INDEX IN INFANT SERUM

ABSTRACT. Reserve albumin concentration (the concentration of albumin available for binding of unconjugated bilirubin) was determined in 95 sera from 76 subjects by dialysis with ¹⁴C-monoacetyl diamino diphenyl sulfone (MADDS). An index, I of bilirubin toxicity in the plasma was calculated for each subject, based on the bilirubin and reserve albumin concentrations, the affinity of bilirubin for serum albumin, and the pH-dependent solubility of bilirubin in the plasma. The values of reserve albumin and of I varied significantly with gestational age, clinical condition (whether sick or well), and serum bilirubin level. The value of reserve albumin was decreased and I was increased in association with clinical factors (e. g., hyperbilirubinemia, hypoxia, acidosis, or sepsis) recognized as increasing the risk for bilirubin encephalopathy. The lowest values of reserve albumin and the highest values of I were found in the least mature and sickest infants.     

LOW RESERVE ALBUMIN FOR BINDING OF BILIRUBIN IN NEONATES WITH DEFICIENCY OF BILIRUBIN EXCRETION AND BRONZE BABY SYNDROME

ABSTRACT. The plasma reserve albumin concentration for binding of bilirubin was found to be low in four newborn infants with deficiency of bilirubin excretion, of whom two had the bronze baby syndrome. Thus, the risk of bilirubin encephalopathy was increased. Also the ratio of binding fraction of albumin, i. e. unconjugated bilirubin plus reserve albumin, to total albumin was low. Possible causes of the low reserve albumin concentration and the ratio are discussed.     

Superiority of intensive phototherapy — Blue double light —in rhesus haemolytic disease

The purpose of the study was to investigate whether intensive phototherapy (blue double light) is superior to ordinary white single light in the treatment of rhesus haemolytic disease (RHD). 71 newborn infants suffering from RHD and with strongly positive direct Coombs' tests were illuminated with blue double light, and 104 infants illuminated with white single light. With the double light treatment, the number of late exchange transfusions was reduced to 1/6 of the number in single light treated infants thereby halving the total number of exchange transfusions. This reduction was significant in infants with mild-to-moderate RHD, as well as in infants with severe RHD. The mean maximum serum bilirubin concentration was significantly lower in the double light treated infants than in the single light treated infants. Correspondingly, significantly fewer double light treated infants than single light treated infants developed moderate or high serum bilirubin concentrations. There were no significant side effects during the phototherapy. To prevent a marked increase of the serum bilirubin concentration after discontinuation of the double light treatment, this therapy was followed by single light treatment. It can be concluded that intensive phototherapy is superior to ordinary phototherapy in the treatment of RHD.     

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

Thirty newborn infants with normal birth weights and uncomplicated hyperbilirubinaemia were studied. Twenty three of these were treated continuously for 24h with intensive phototherapy (blue double light), and seven untreated infants served as controls. During the treatment the serum concentrations of total bilirubin and unbound bilirubin in diluted serum measured by the peroxidase method were markedly reduced. The binding affinity of bilirubin to its high affinity site on serum albumin was not affected. During the treatment a slight decrease of the serum albumin concentration occurred, and the possible causes of this observation are discussed.     

INCREASE IN BILIRUBIN BINDING TO ALBUMIN WITH CORRECTION OF NEONATAL ACIDOSIS

Abstract. Twenty-six serial measurements of free bilirubin concentration and apparent association constant of bilirubin for albumin (Ka) at a bilirubin: albumin molar ratio of 0.8 were performed and compared with baseline values in 11 newborn infants with acidosis before treatment and during recovery from acidosis. When arterial pH was corrected from 7.12±0.02 (Mean±S.E.M.) to 7.34±0.02, there was a significant decrease in serum free bilirubin concentration and a significant increase in the Ka at molar ratio 0.8. The data offer in vivo evidence that correction of acidosis in the neonate results in an improvement of the apparent bilirubin binding affinity of albumin.     

POSTNATAL CHANGES IN THE ABILITY OF PLASMA ALBUMIN TO BIND BILIRUBIN

ABSTRACT. The plasma concentrations of total albumin, unconjugated bilirubin and reserve albumin for bilirubin binding were determined in 407 healthy infants of various age up to eight days. The albumin reserve was measured using monoacetyldiaminodiphenyl-sulfone (MADDS) as a deputy ligand for bilirubin. The fraction of albumin capable of binding bilirubin was calculated as the sum of the concentrations of bilirubin and reserve albumin, divided by the total albumin concentration. Our data showed that this fraction was low (average 0.36) and did not change during the first 24 hours of life, and in this period it was independent of the maturity of the infant, as expressed by its birth weight or gestational age. From about 24 hours of life, the fraction began to increase. This increase came to an end about 60 hours after birth, and no further changes were seen during the following five days. The level of the bilirubin-binding fraction reached 60 hours after birth was related to the maturity of the infant: It increased with increasing birth weight up to 3000 g and with increasing gestational age up to 275 days, when on an average it was about 0.58. The fraction of binding albumin was independent of the sex.     

Albumin Binding Properties in Relation to Bilirubin and Albumin Concentrations during the First Week of Life

ABSTRACT. In 19 non-jaundiced and 22 jaundiced neonates, the serum albumin and bilirubin concentrations were measured during the first week of life. Some of the neonates were followed longitudinally. The albumin binding properties were evaluated by determining the reserve albumin concentration for monoacetyldiaminodiphenyl sulphone (MADDS), a deputy ligand for bilirubin. The reserve albumin concentration for MADDS increased with postnatal age. The reason for this increase is still unexplained. There was an inverse relation between the bilirubin and the reserve albumin concentrations, but when the bilirubin concentration increased by 1 μmol/l, the reserve albumin concentration for MADDS decreased by only 0.2 μmol/l. This shows that the reserve albumin concentration for MADDS does not give a direct measure of the bilirubin binding ability of the serum albumin molecule. In spite of this, it is still possible that a low reserve albumin concentration for MADDS is a risk factor for bilirubin encephalopathy.     

Albumin binding properties in relation to bilirubin and albumin concentrations during the first week of life

In 19 non-jaundiced and 22 jaundiced neonates, the serum albumin and bilirubin concentrations were measured during the first week of life. Some of the neonates were followed longitudinally. The albumin binding properties were evaluated by determining the reserve albumin concentration for monoacetyldiaminodiphenyl sulphone (MADDS), a deputy ligand for bilirubin. The reserve albumin concentration for MADDS increased with postnatal age. The reason for this increase is still unexplained. There was an inverse relation between the bilirubin and the reserve albumin concentrations, but when the bilirubin concentration increased by 1 mumol/l, the reserve albumin concentration for MADDS decreased by only 0.2 mumol/l. This shows that the reserve albumin concentration for MADDS does not give a direct measure of the bilirubin binding ability of the serum albumin molecule. In spite of this, it is still possible that a low reserve albumin concentration for MADDS is a risk factor for bilirubin encephalopathy.     

Hematin and bilirubin binding to human serum albumin and newborn serum

In jaundiced newborn infants, hemolytic disease is considered a risk factor for kernicterus due to the suspected competition between bilirubin and other hemoglobin breakdown products for albumin binding. We have studied the effect of hematin on bilirubin-albumin binding using the peroxidase assay and a light-scattering technique for measuring unbound bilirubin. Our results show that hematin does not affect bilirubin-albumin binding. To determine if other albumin binding functions are affected by hematin, we used a microdialysis rate technique employing two ligands, diazepam and monoacetyldiaminodiphenyl sulfone (MADDS). Hematin does not utilize the diazepam binding function of albumin, but does decrease the albumin binding of MADDS. The results of this study indicate that the MADDS and bilirubin binding functions are not identical. The clinical usefulness of reserve albumin equivalent determination using MADDS is discussed.     

ALBUMIN ADMINISTRATION COMBINED WITH PHOTOTHERAPY IN TREATMENT OF HYPERBILIRUBINAEMIA IN LOW-BIRTH-WEIGHT INFANTS

ABSTRACT. Ebbesen, F., and Brodersen, R. (Department of Neonatology, Rigshospitalet, Copenhagen and Institute of Medical Biochemistry, Aarhus, Denmark). Albumin administration combined with phototherapy in treatment of hyperbilirubinaemia in low-birth-weight infants. Acta Paediatr Scand, 70:649,.–Fifty-nine jaundiced light treated newborn infants with low birth weight were studied. At onset of phototherapy 30 infants received 1 g human serum albumin per kg body weight as a 9 % solution containing sodium caprylate and N-acetyltryptophan as stabilizers. 29 infants did not receive human serum albumin and served as controls. Blood samples were taken before initiation of the therapy and again 24 and 48 h thereafter, and the following determinations were made: Serum concentrations of unconjugated bilirubin, albumin, reserve albumin for binding of bilirubin by the [^l4C]-MADDS method, packed cell volume and pH. Before infusion of albumin it was found that the binding fraction of serum albumin, i.e. the sum of the serum concentrations of bilirubin-albumin and reserve albumin, constituted about half of the total serum albumin concentration. The other half was non-binding, in agreement with previous findings in neonates. The effect of albumin therapy was mainly an unexpected increase of the non-binding fraction of serum albumin, while the increase of the serum reserve albumin concentration was small and the concentration of bilirubin-albumin was not changed.     

Hematin and Bilirubin Binding to Human Serum Albumin and Newborn Serum

ABSTRACT. In jaundiced newborn infants, hemolytic disease is considered a risk factor for kernicterus due to the suspected competition between bilirubin and other hemoglobin breakdown products for albumin binding. We have studied the effect of hematin on bilirubin-albumin binding using the peroxidase assay and a light-scattering technique for measuring unbound bilirubin. Our results show that hematin does not affect bilirubin-albumin binding. To determine if other albumin binding functions are affected by hematin, we used a microdialysis rate technique employing two ligands, diazepam and monoacetyldiaminodiphenyl sulfone (MADDS). Hematin does not utilize the diazepam binding function of albumin, but does decrease the albumin binding of MADDS. The results of this study indicate that the MADDS and bilirubin binding functions are not identical. The clinical usefulness of reserve albumin equivalent determination using MADDS is discussed.     

Effect of lactate, pyruvate, acetone, acetoacetate, and beta-hydroxybutyrate on albumin binding of bilirubin

Lactate, pyruvate, acetone, acetoacetate, and beta-hydroxybutyrate were tested for their bilirubin-displacing effect on human serum albumin. Only lactate had a significant effect at levels found in asphyxiated infants (up to 20 mM). The reserve albumin equivalent for binding bilirubin was determined, using the deputy ligand monoacetyldiaminodiphenyl sulfone (MADDS), in adult human serum albumin solution, neonatal serum, and neonatal albumin solution. Twenty mM lactate caused a 23% decrease of reserve albumin when adult albumin was used, but did not cause any change of binding when neonatal serum or neonatal albumin solution was used. It is unlikely that endogenous substances, acting as competitive ligands, cause the low binding affinity of albumin for bilirubin in sick, premature infants.     

DEPENDENCE OF THE EFFICIENCY OF PHOTOTHERAPY ON PLASMA BILIRUBIN CONCENTRATION

ABSTRACT. 407 newborns with idiopathic transitory hyperbilirubinaemia were examined with regard to the decrease in serum bilirubin levels during 24 hours of intermittent phototherapy (12 hours of light exposure). The photoeffect (i. e. decrease of serum bilirubin concentration after 24 hours of therapy) showed a unique and predictable nonlinear correlation with the plasma bilirubin concentration before treatment. This relationship can be used for individualizing the duration of phototherapy and the dose of light. The apparent effect of birth weight, gestational age, and postnatal age on the efficiency of phototreatment is only due to differing initial levels of bilirubin concentration. Intermittent illumination seemed to be more efficient than continuous.     

The Serum Reserve Albumin Concentration for Monoacetyldiaminodiphenyl Sulphone and Auditory Evoked Responses during Neonatal Hyperbilirubinaemia

ABSTRACT. Auditory brainstem evoked responses (ABR) were recorded in 9 neonates with hyperbilirubinaemia. Pathological recordings were found in two children showing absence of waves and prolonged latencies. There was no correlation between latencies to waves and the total serum bilirubin concentration. The serum reserve albumin concentration for monoacetyldiaminodiphenyl sulphone (MADDS) was, however, inversely related to the latencies in the ABR recordings. Our findings suggest that the binding properties of serum albumin contribute to the risk of bilirubin toxicity and that, in this study, the reserve albumin concentration for MADDS seemed to be of Heater significance than the total bilirubin concentration.     

The serum reserve albumin concentration for monoacetyldiaminodiphenyl sulphone and auditory evoked responses during neonatal hyperbilirubinaemia

Auditory brainstem evoked responses (ABR) were recorded in 9 neonates with hyperbilirubinaemia. Pathological recordings were found in two children showing absence of waves and prolonged latencies. There was no correlation between latencies to waves and the total serum bilirubin concentration. The serum reserve albumin concentration for monoacetyldiaminodiphenyl sulphone (MADDS) was, however, inversely related to the latencies in the ABR recordings. Our findings suggest that the binding properties of serum albumin contribute to the risk of bilirubin toxicity and that, in this study, the reserve albumin concentration for MADDS seemed to be of greater significance than the total bilirubin concentration.     

Ceftriaxone effect on bilirubin-albumin binding

The effect of ceftriaxone on bilirubin-albumin binding was measured in vitro using the peroxidase method with human serum albumin and a dialysis rate method with adult and newborn serum. Ceftriaxone competes with bilirubin for binding to human serum albumin; the displacement constant is 1.5 X 10(4) L/mol. Therapeutic levels of ceftriaxone decrease the reserve albumin concentration in newborn serum by 39%. These results indicate that ceftriaxone may increase the risk of bilirubin encephalopathy in jaundiced premature infants.     

Reduced Albumin Binding of MADDS–a Measure for Bilirubin Binding–in Sick Children

ABSTRACT. The reserve albumin concentration for binding of MADDS (monoacetyldiaminodiphenyl sulphone) in plasma is used as a measure of the reserve albumin concentration for binding of unconjugated bilirubin. The aim of the present study was to investigate whether a reduction in the reserve albumin concentration for binding of MADDS could exist in sick children after 5 months of age, where the bilirubin binding properties of the albumin has reached the adult level. The material included 75 children, 1-15 years of age with mild infections, servere bacterial infections, acute viral hepatitis, chronic hepatic diseases or uraemia, and a control group of 22 healthy children. The reserve albumin concentration was significantly lower in children with severe bacterial infections, acute viral hepatitis, and uraemia, than in healthy children ( p <0.01), while the reserve albumin concentration in children with mild infections and chronic hepatic diseases did not differ significantly from that of the control group ( p > 0.05). The total albumin concentration in plasma in either of the groups of sick children did not differ significantly from that of the healthy children. The plasma concentration of unconjugated bilirubin was elevated in the group of children with acute viral hepatitis, but not enough to influence the concentration of reserve albumin for binding of MADDS to a significant degree. The reserve albumin concentration was significantly lower in children with acute viral hepatitis than in children with severe bacterial infections ( p <0.05).