THE THYROID IN CHILDREN

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.

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Determination of Unbound Bilirubin in the Serum of Newborns

Clinical Chemistry ◽

10.1093/clinchem/20.7.783 ◽

1974 ◽

Vol 20 (7) ◽

pp. 783-789 ◽

Cited By ~ 178

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.

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Displacement of phenytoin from serum protein carriers by antibiotics: studies with ceftriaxone, nafcillin, and sulfamethoxazole

Clinical Chemistry ◽

10.1093/clinchem/37.1.98 ◽

1991 ◽

Vol 37 (1) ◽

pp. 98-100 ◽

Cited By ~ 27

Author(s):

Amltava Dasgupta ◽

David A Dennen ◽

Roger Dean ◽

Ronald W McLawhon

Keyword(s):

Valproic Acid ◽

Salicylic Acid ◽

Antibiotic Therapy ◽

Serum Protein ◽

In Vitro Studies ◽

Concomitant Therapy ◽

Protein Carriers ◽

Predicted Values

Abstract Increased concentrations of free phenytoin in serum, attributable to the displacement of this anticonvulsant by other drugs, e.g., valproic acid and salicylic acid, have been reported. We observed in vitro and in vivo displacement of phenytoin by the antibiotics ceftriaxone, nafcillin, and sulfamethoxazole. In vitro studies demonstrated statistically significant (P less than 0.05) increases in free phenytoin after the addition of specific antibiotics to patients' sera and to phenytoin-supplemented sera from controls. Concentrations of free phenytoin in vivo, predicted by an equation we have found to be accurate for albumin concentrations greater than or equal to 32 g/L, were consistently underestimated in patients receiving concomitant therapy with the antibiotics studied. The concentrations of free phenytoin decreased towards the predicted values when the antibiotic therapy was discontinued. We conclude that ceftriaxone, nafcillin, and sulfamethoxazole can displace phenytoin from the usual protein carriers found in serum, in vitro and in vivo.

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Bilirubin-albumin binding capacity in term and preterm infants

Paediatrica Indonesiana ◽

10.14238/pi47.1.2007.32-4 ◽

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.

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78 Effect of human serum on the in vitro Anti-HIV-1 activity of hept derivatives as related to their lipophilicity and serum protein binding capacity

Antiviral Research ◽

10.1016/0166-3542(93)90456-s ◽

1993 ◽

Vol 20 ◽

pp. 81

Keyword(s):

Protein Binding ◽

Human Serum ◽

Serum Protein ◽

Binding Capacity ◽

Serum Protein Binding ◽

Protein Binding Capacity ◽

Anti Hiv ◽

Hept Derivatives ◽

Hiv 1

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Investigation of the Free and Total Thyroxine-binding Capacity of Plasma Proteins in Thyroid Disorders

Nuklearmedizin ◽

10.1055/s-0038-1624755 ◽

1971 ◽

Vol 10 (04) ◽

pp. 299-304

Author(s):

József Takó ◽

János Fischer ◽

Jusztina Juhász ◽

Ilona Sztraka ◽

István Kapus ◽

...

Keyword(s):

Blood Cell ◽

Thyroid Function ◽

Oral Contraceptives ◽

Red Blood Cell ◽

Plasma Proteins ◽

Binding Capacity ◽

Thyroid Disorders ◽

Thyroid Function Tests ◽

Total Thyroxine

SummaryThe results of thyroid function tests have been compared with data on the thyroxine-binding capacity of plasma proteins in hyper-, hypo- and euthyroid cases, the latter including women taking oral contraceptives (Infecundin). It was found that there exists a significant correlation of exponential nature between the in vitro red blood cell 125I-triiodothyronine uptake (RCU) and the free thyroxine-binding capacity of the thyroxine-inding globulin (TBG).

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In Vitro and in Vivo Comparison of Binding of 99m-Tc-Iabeled Anti-CEA MAb F33-104 with 99m-Tc-labeled Anti-CEA MAb BW431/26

Nuklearmedizin ◽

10.1055/s-0038-1632202 ◽

1999 ◽

Vol 38 (04) ◽

pp. 115-119

Author(s):

N. Oriuchi ◽

S. Sugiyama ◽

M. Kuroki ◽

Y. Matsuoka ◽

S. Tanada ◽

...

Keyword(s):

Nude Mice ◽

Binding Capacity ◽

Colon Adenocarcinoma ◽

Human Colon ◽

Cell Binding ◽

Vitro Binding ◽

Labeling Method ◽

Human Colon Adenocarcinoma

Summary Aim: The purpose of this study was to assess the potential for radioimmunodetection (RAID) of murine anti-carcinoembryonic antigen (CEA) monoclonal antibody (MAb) F33-104 labeled with technetium-99m (99m-Tc) by a reduction-mediated labeling method. Methods: The binding capacity of 99m-Tc-labeled anti-CEA MAb F33-104 with CEA by means of in vitro procedures such as immunoradiometric assay and cell binding assay and the biodistribution of 99m-Tc-labeled anti-CEA MAb F33-104 in normal nude mice and nude mice bearing human colon adenocarcinoma LS180 tumor were investigated and compared with 99m-Tc-labeled anti-CEA MAb BW431/26. Results: The in vitro binding rate of 99m-Tc-labeled anti-CEA MAb F33-104 with CEA in solution and attached to the cell membrane was significantly higher than 99m-Tclabeled anti-CEA MAb BW431/261 (31.4 ± 0.95% vs. 11.9 ± 0.55% at 100 ng/mL of soluble CEA, 83.5 ± 2.84% vs. 54.0 ± 2.54% at 107 of LS 180 cells). In vivo, accumulation of 99m-Tc-labeled anti-CEA MAb F33-104 was higher at 18 h postinjection than 99m-Tc-labeled anti-CEA MAb BW431/26 (20.1 ± 3.50% ID/g vs. 14.4 ± 3.30% ID/g). 99m-Tcactivity in the kidneys of nude mice bearing tumor was higher at 18 h postinjection than at 3 h (12.8 ± 2.10% ID/g vs. 8.01 ± 2.40% ID/g of 99m-Tc-labeled anti-CEA MAb F33-104, 10.7 ± 1.70% ID/g vs. 8.10 ± 1.75% ID/g of 99m-Tc-labeled anti-CEA MAb BW431/26). Conclusion: 99m-Tc-labeled anti-CEA MAb F33-104 is a potential novel agent for RAID of recurrent colorectal cancer.

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Preincubation with Sn-complexes causes intensive intracellular retention of 99mTc in thyroid cells in vitro

Nuklearmedizin ◽

10.3413/nukmed-0450-11-12 ◽

2012 ◽

Vol 51 (05) ◽

pp. 179-185 ◽

Cited By ~ 3

Author(s):

M. Wendisch ◽

D. Aurich ◽

R. Runge ◽

R. Freudenberg ◽

J. Kotzerke ◽

...

Keyword(s):

Cell Model ◽

Low Energy ◽

Thyroid Cells ◽

Low Energy Electrons ◽

A Cell ◽

Vitro Model ◽

Uptake Studies ◽

Radiobiological Effects ◽

Radioactivity Retention

SummaryTechnetium radiopharmaceuticals are well established in nuclear medicine. Besides its well-known gamma radiation, 99mTc emits an average of five Auger and internal conversion electrons per decay. The biological toxicity of these low-energy, high-LET (linear energy transfer) emissions is a controversial subject. One aim of this study was to estimate in a cell model how much 99mTc can be present in exposed cells and which radiobiological effects could be estimated in 99mTc-overloaded cells. Methods: Sodium iodine symporter (NIS)- positive thyroid cells were used. 99mTc-uptake studies were performed after preincubation with a non-radioactive (cold) stannous pyro - phosphate kit solution or as a standard 99mTc pyrophosphate kit preparation or with pure pertechnetate solution. Survival curves were analyzed from colony-forming assays. Results: Preincubation with stannous complexes causes irreversible intracellular radioactivity retention of 99mTc and is followed by further pertechnetate influx to an unexpectedly high 99mTc level. The uptake of 99mTc pertechnetate in NIS-positive cells can be modified using stannous pyrophosphate from 3–5% to >80%. The maximum possible cellular uptake of 99mTc was 90 Bq/cell. Compared with nearly pure extracellular irradiation from routine 99mTc complexes, cell survival was reduced by 3–4 orders of magnitude after preincubation with stannous pyrophosphate. Conclusions: Intra cellular 99mTc retention is related to reduced survival, which is most likely mediated by the emission of low-energy electrons. Our findings show that the described experiments constitute a simple and useful in vitro model for radiobiological investigations in a cell model.

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In Vitro Cellular Uptake Studies of Self-Assembled Fluorinated Nanoparticles Labelled with Antibodies

Nanomaterials ◽

10.3390/nano11081906 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1906

Author(s):

Mona Atabakhshi-Kashi ◽

Mónica Carril ◽

Hossein Mahdavi ◽

Wolfgang J. Parak ◽

Carolina Carrillo-Carrion ◽

...

Keyword(s):

Flow Cytometry ◽

Cellular Uptake ◽

Hydrophobic Interactions ◽

Intrinsic Properties ◽

Wide Range ◽

Self Assembled ◽

Uptake Studies ◽

Targeting Ability ◽

Fluorinated Nanoparticles

Nanoparticles (NPs) functionalized with antibodies (Abs) on their surface are used in a wide range of bioapplications. Whereas the attachment of antibodies to single NPs to trigger the internalization in cells via receptor-mediated endocytosis has been widely studied, the conjugation of antibodies to larger NP assemblies has been much less explored. Taking into account that NP assemblies may be advantageous for some specific applications, the possibility of incorporating targeting ligands is quite important. Herein, we performed the effective conjugation of antibodies onto a fluorescent NP assembly, which consisted of fluorinated Quantum Dots (QD) self-assembled through fluorine–fluorine hydrophobic interactions. Cellular uptake studies by confocal microscopy and flow cytometry revealed that the NP assembly underwent the same uptake procedure as individual NPs; that is, the antibodies retained their targeting ability once attached to the nanoassembly, and the NP assembly preserved its intrinsic properties (i.e., fluorescence in the case of QD nanoassembly).

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