Determination of Unbound Bilirubin in the Serum of Newborns

1974 ◽  
Vol 20 (7) ◽  
pp. 783-789 ◽  
Author(s):  
Jorgen Jacobsen ◽  
Richard P Wennberg
Keyword(s):  
Binding Capacity ◽  
Newborn Infants ◽  
Albumin Binding ◽  
Initial Oxidation ◽  
High Affinity ◽  
Normal Human ◽  
Unbound Bilirubin ◽  
Rate Limiting

Abstract An enzymatic assay is described for non-albuminbound bilirubin in the serum of newborn infants. Unbound bilirubin is oxidized to colorless compounds by ethyl hydroperoxide in the presence of horseradish peroxidase (EC 1.11.1.7), while albumin-bound bilirubin is protected from oxidation. Because the equilibrium between albumin and bilirubin occurs rapidly, the oxidation step is rate limiting, and the initial oxidation velocity of total bilirubin is proportional to the unbound bilirubin concentration. By titrating serum with bilirubin in vitro, the association constant and binding capacity of high-affinity sites for albumin binding can be determined. Normal human serum albumin tightly binds 1 mole of bilirubin per mole of albumin (binding constant, 2-4 x 108 liter/mol). Although weaker secondary binding occurs, the unbound bilirubin fraction increases rapidly after the high-affinity binding sites are saturated. Compromised newborns may have a decreased apparent binding capacity and (or) binding affinity. The method can be used to assess the risk of a jaundiced infant for bilirubin encephalopathy.

scholarly journals Bilirubin-albumin binding capacity in term and preterm infants

2007 ◽  
Vol 47 (1) ◽  
pp. 32
Author(s):  
M. Basalamah ◽  
Achmad Surjono
Keyword(s):  
Preterm Infants ◽  
Binding Capacity ◽  
Linear Regression Analysis ◽  
Newborn Infants ◽  
Albumin Binding ◽  
Term Infants ◽  
A Value ◽  
Significant Difference ◽  
Unbound Bilirubin

Background The risk of kernicterus remains a problem injaundiced newborn especially in low birth weight infants.Kernicterus can develop at low bilirubin levels. Bilirubin-albuminbinding plays an important role in its pathogenesis. Bilirubinalbumin binding concentration can also be used as the cut-offpoint in the administration of phototeraphy.Objective To determine the pattern of albumin bindingconcentration in serum model in vitro and in serum of prematureand term newborn infants from cord blood sample.Methods This study was conducted in Installation of Maternal-Perinatal Dr. Sardjito Hospital from August-September 2004.Blood cord samples from 20 term and 17 preterm infants wereanalysed. Total bilirubin was measured spectrophotometrically andunbound bilirubin concentration was determined by horseradishperoxidase oxidation using UB-analyzer apparatus micromethod.Student t test and linear regression analysis were performed.Results Bilirubin-albumin binding capacity of term infants showeda statistically significant difference compared to that of prematureinfants (18.9±2.1 mg/dl vs 10.2±3.6 mg/dl, P<0.001). This cut-off level approximately reflected a value of unbound bilirubin of1 mg/dl in term and 0.5 mg/dl in premature infants.Conclusions There is a different pattern of bilirubin-albuminbinding capacity between term and preterm infants which is higherin term infants. Bilirubin level of 19 mg/dl and 10 mg/dl in termand preterm newborn, respectively, can be used as cut-off pointto perform more aggressive intervention, such as phototeraphy,and to lower the risk of kernicterus.

THE THYROID IN CHILDREN

PEDIATRICS ◽  
1962 ◽  
Vol 30 (1) ◽  
pp. 27-31
Author(s):  
Ralph H. Kunstadter ◽  
Harvey Buchman ◽  
Morad Jacobson ◽  
Leo Oliner
Keyword(s):  
Serum Protein ◽  
Binding Capacity ◽  
Newborn Infants ◽  
Normal Children ◽  
Protein Carriers ◽  
Uptake Studies

The in vitro erythrocyte uptake studies of radioactive 1-triiodothyronine in 70 normal children, ranging in age from newborn infants to 13 years, are presented. The data reveal elevated uptake values in these children as compared to adults, indicating alteration in binding capacity of thyroxin-binding serum protein carriers, in all probability a reduction in thyroxin-binding prealbumin capacity.

Determination of Blood Sugar in Newborn Infants

PEDIATRICS ◽  
1961 ◽  
Vol 28 (5) ◽  
pp. 850-851
Author(s):  
GLORIA S. BAENS ◽  
WILLIAM OH ◽  
EVELYN LUNDEEN ◽  
MARVIN CORNBLATH
Keyword(s):  
Blood Sugar ◽  
Newborn Infants ◽  
Newborn Period ◽  
Claude Bernard

To the Editor: Recently, there has been a renewed interest in the level of blood sugar in the newborn period, with very low or zero blood sugars being reported1, 2 In some of these reports there is no mention of how the blood was collected, how long it was permitted to stand, how it was precipitated, or analyzed. As reviewed by Peters and Van Slyke,3 the disappearance of sugar from blood in vitro has been well documented since the time of Claude Bernard.

Determination of contact sensitization potential of chemicals using in vitro reconstructed normal human epidermal model EpiDerm: Impact of the modality of application

2016 ◽  
Vol 258 ◽  
pp. S230
Author(s):  
S. Letasiova ◽  
E. Corsini ◽  
V. Galbiati ◽  
H. Kandarova ◽  
D. Lehmeier ◽  
...  
Keyword(s):  
Contact Sensitization ◽  
Normal Human

scholarly journals Substrate Proteins Take Shape at an Improved Bacterial Translocon

2018 ◽  
Vol 201 (1) ◽  
Author(s):  
Donald Oliver
Keyword(s):  
Protein Transport ◽  
Protein Translocation ◽  
Membrane Vesicles ◽  
Transport Models ◽  
Content Type ◽  
Rate Limiting ◽  
Substrate Proteins

ABSTRACTCharacterization of Sec-dependent bacterial protein transport has often relied on anin vitroprotein translocation system comprised in part ofEscherichia coliinverted inner membrane vesicles or, more recently, purified SecYEG translocons reconstituted into liposomes using mostly a single substrate (proOmpA). A paper published in this issue (P. Bariya and L. Randall, J Bacteriol 201:e00493-18, 2019, https://doi.org/10.1128/JB.00493-18) finds that inclusion of SecA protein during SecYEG proteoliposome reconstitution dramatically improves the number of active translocons. This experimentally useful and intriguing result that may arise from SecA membrane integration properties is discussed here. Furthermore, determination of the rate-limiting transport step for nine different substrates implicates the mature region distal to the signal peptide in the observed rate constant differences, indicating that more nuanced transport models that respond to differences in protein sequence and structure are needed.

scholarly journals DETERMINATION OF l-HISTIDINE IN NANOGRAM AMOUNTS AND THE QUESTION OF ITS OCCURRENCE IN MAST CELLS

1972 ◽  
Vol 20 (11) ◽  
pp. 917-922 ◽  
Author(s):  
DAVID I. WILKINSON ◽  
DAVID GLICK
Keyword(s):  
Mast Cells ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Peritoneal Mast Cells ◽  
Before And After ◽  
Chromatographic Detection ◽  
Rat Peritoneal Mast Cells ◽  
Rate Limiting

In an attempt to clarify the question of whether histidine is stored in the mast cell for coversion to histamine or whether the rate of conversion is rapid enough to prevent accumulation of histidine so that the rate-limiting step is the histidine uptake, it was found that no histidine was demonstrable in rat peritoneal mast cells by either quantitative analysis or paper chromatographic detection. Microadaptation of Hassall's method, based on conversion of l-histidine by histidase to urocanic acid and measurement of the latter by its absorbance at 277 nm, was made to permit determination of histidine in nanogram amounts in the presence of histamine. This adaptation was found reliable when compared with the o-phthalaldehyde method in estimation of l-histidine in serum and in insulin hydrolysate, and then it was applied to analysis of mast cells before and after l-histidine uptake in vitro. The adaptation should be generally useful in microanalysis of l-histidine in histologically and cytologically defined samples.

IMMUNIZATION AGAINST AN INHIBIN SUBUNIT PRODUCED BY RECOMBINANT DNA TECHNIQUES RESULTS IN INCREASED OVULATION RATE IN SHEEP

1987 ◽  
Vol 114 (2) ◽  
pp. R1-R4 ◽  
Author(s):  
R.G. Forage ◽  
R.W. Brown ◽  
K.J. Oliver ◽  
B.T. Atrache ◽  
P.L. Devine ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Recombinant Dna ◽  
Binding Capacity ◽  
Control Groups ◽  
Keyhole Limpet Haemocyanin ◽  
A Subunit ◽  
Recombinant Dna Techniques

ABSTRACT Seven Merino–Border Leicester cross–bred ewes were immunized with a purified fusion protein, produced by recombinant DNA methods, of the a subunit of bovine inhibin. Four animals were immunized with the fusion protein alone and three with a conjugate made by coupling the fusion protein to keyhole limpet haemocyanin (KLH) using glutaraldehyde. Each animal received four injections of the fusion protein over 93 days. The animals were synchronized using progestagen sponges and subjected to laparoscopy for the determination of ovulation rates in two consecutive cycles (days 115 and 135). The immunized animals had overall mean ovulation rates for each cycle of 3.4 and 3.4 which was significantly (P < 0.001) above the rates of 1.1 and 1.4 determined for the controls, which had either received no treatment (n=5) or had been immunized with 300 μg KLH (n=4). Analysis of antisera taken on day 115 showed significant fusion protein antibodies and iodinated inhibin–binding capacity in the test but not control groups. Furthermore, antisera to the fusion protein in four out of seven ewes neutralized the inhibin bioactivity of ovine follicular fluid in an in–vitro bioassay. These data demonstrate that neutralization of inhibin can be effected by immunization with bovine inhibin a subunit and that such immunization results in increased ovulation rates as predicted from the biological role of inhibin as a suppressor of FSH.

scholarly journals Total folate binding capacity of normal human plasma, and variations in uremia, cirrhosis, and pregnancy

Blood ◽  
1976 ◽  
Vol 48 (6) ◽  
pp. 911-921 ◽  
Author(s):  
N Colman ◽  
V Herbert
Keyword(s):  
Lactobacillus Casei ◽  
Binding Capacity ◽  
Gel Filtration ◽  
Normal Subjects ◽  
Serum Folate ◽  
Folate Level ◽  
High Affinity ◽  
Serum Folate Level ◽  
Normal Human ◽  
Clinical Conditions

The current study presents evidence that all human serum contains a class of high-affinity folate binders (KA=2.8 X10(10 liters/mole), which migrate as a single peak on gel filtration. Failure of previous studies to detect this characteristic in all but a minority of subjects is attributable to its variable, often total, saturation. Direct measurement of the total folate binding capacity (TFBC) has been made possible by dissociation of endogenous folate-binder complexes at acid pH, removal of free folate by coated charcoal, and radiofolate tagging. This procedure does not appear to significantly denature the binders, which release and rebind similar quantities of 3H-PGA. In 20 normal subjects, TFBC ranged from 100 to 325 pg/ml (mean+/-SE = 174+/-16), and was always at least 33% saturated. In three clinical conditions, all associated with elevated unsaturated folate binding capacity, three different patterns emerged when TFBC was also measured. Uremic subjects had significantly elevated mean TFBC with normal saturation. In cirrhotic subjects, mean TFBC approximated normal, but saturation was significantly decreased. In pregnancy, two groups were seen: one with increased TFBC and the other with a normal TFBC, some of whom had decreased saturation. Lactobacillus casei serum folate level was about 30 times greater than the TFBC; there was no correlation between the two measurements.

scholarly journals Total folate binding capacity of normal human plasma, and variations in uremia, cirrhosis, and pregnancy

Blood ◽  
1976 ◽  
Vol 48 (6) ◽  
pp. 911-921 ◽  
Author(s):  
N Colman ◽  
V Herbert
Keyword(s):  
Lactobacillus Casei ◽  
Binding Capacity ◽  
Gel Filtration ◽  
Normal Subjects ◽  
Serum Folate ◽  
Folate Level ◽  
High Affinity ◽  
Serum Folate Level ◽  
Normal Human ◽  
Clinical Conditions

Abstract The current study presents evidence that all human serum contains a class of high-affinity folate binders (KA=2.8 X10(10 liters/mole), which migrate as a single peak on gel filtration. Failure of previous studies to detect this characteristic in all but a minority of subjects is attributable to its variable, often total, saturation. Direct measurement of the total folate binding capacity (TFBC) has been made possible by dissociation of endogenous folate-binder complexes at acid pH, removal of free folate by coated charcoal, and radiofolate tagging. This procedure does not appear to significantly denature the binders, which release and rebind similar quantities of 3H-PGA. In 20 normal subjects, TFBC ranged from 100 to 325 pg/ml (mean+/-SE = 174+/-16), and was always at least 33% saturated. In three clinical conditions, all associated with elevated unsaturated folate binding capacity, three different patterns emerged when TFBC was also measured. Uremic subjects had significantly elevated mean TFBC with normal saturation. In cirrhotic subjects, mean TFBC approximated normal, but saturation was significantly decreased. In pregnancy, two groups were seen: one with increased TFBC and the other with a normal TFBC, some of whom had decreased saturation. Lactobacillus casei serum folate level was about 30 times greater than the TFBC; there was no correlation between the two measurements.

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