Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0393754 (HSA)
 2,996 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Direct labeling involves 99mTc binding to different donor groups on the protein, giving multiple binding sites of various affinities resulting in an in vivo instability. The stability has been considerably improved by activating the antibody using a controlled reduction reaction (using 2-aminoethanethiol). This reaction generates sulfhydryl groups, which are known to strongly bind 99mTc. The direct 99mTc antibody labeling method was explored using whole antibodies and fragments. Analytical methods were developed for routine evaluation of radiolabeling yield and in vitro stability. Stable direct antibody labeling with 99mTc requires the generation of sulfhydryl groups, which show high affinity binding sites for 99mTc. Such groups are obtained with 2-aminoethanethiol (AET), which induces the reduction of the intrachain or interchain disulfide bond, with no structural deterioration or any loss of immunobiological activity of the antibody. The development of fast, reliable analytical methods has made possible the qualitative and quantitative assessment of technetium species generated by the radiolabeling process. Labeling stability is determined by competition of the 99mTc-antibody bond with three ligands, Chelex 100 (a metal chelate-type resin), free DTPA solution and 1% HSA solution. Very good 99mTc-antibody stability is obtained with activated IgG (IgGa) and Fab' fragment, which makes these substances possible candidates for immunoscintigraphy use.
Int J Rad Appl Instrum B 1991
PMID:Direct 99mTc labeling of monoclonal antibodies: radiolabeling and in vitro stability. 178 78

The conjugation of a complex formed by reacting RhCl3 with cysteine to human serum albumin has been investigated. Approximately 50% of the rhodium (labeled with 105Rh) was converted to the complex. Conjugation of the complex to HSA via the ECDI method resulted in yields of approximately 40% of the total rhodium or approximately 80% of the Rh-cysteine complex. No conjugation was observed in the absence of the ECDI. At approximately equal molar concentrations of rhodium and HSA, an average of approximately 0.4 rhodium atoms per HSA molecule was achieved.
Int J Rad Appl Instrum A 1990
PMID:Labeling of human serum albumin with 105Rh-cysteine complexes. 215 47

A bifunctional ligand 4-(p-aminobenzyl)-diethylenetriamine has been synthesized. 105Rh complexes with this ligand were prepared with an overall yield of 79% at pH 9.0 in bicarbonate buffer. The preformed complex was converted to the isothiocyanate derivative using thiophosgene. Conjugation yields of 75% with IgG and 85% with HSA could be obtained for a 4 h conjugation reaction. Affinity chromatography of human-IgG coupled to the rhodium complex in an anti-human IgG agarose gel indicated no denaturation of the labeled protein. The procedure reported here can be adapted for the preparation of 105Rh-labeled antibodies for therapeutic applications.
Int J Rad Appl Instrum B 1990
PMID:Labeling of proteins using [105Rh]Rh-4-(p-aminobenzyl)-diethylenetriamine. 238 50

After incubation of both serum and HSA solutions with radioactive lanthanide complexes the binding constants of the corresponding lanthanide-protein complexes formed in the protein solutions under physiologic conditions, pH: 7.4, temperature: 310 K, isotonic ionic strength: 0.15 mol/L, were determined. The association constants of the lanthanide-protein complexes formed both in serum and HSA-solutions are equal within the experimental error. In conclusion, serum albumin binding predominates for the radiolanthanides. With the decrease of the ionic radii from 1.034 A (Ce) to 0.858 (Yb) the association constants increased by five orders of magnitude from 1 g Kpr = 4.90 (Ce) to 1 g Kpr = 9.54 (Yb). Further, a serum fractionation with alcohol was carried out to prove that the albumin fraction of serum is responsible for the lanthanide binding in blood.
Int J Rad Appl Instrum A 1988
PMID:Stabilities of lanthanide-protein complexes. 283 44

Distribution of 67Ga-citrate in inflammatory tissues was determined, and correlation between the 67Ga-uptake and capillary permeability of plasma from blood vessels in the inflammatory tissue was elucidated, by quantitative whole body autoradiography and double tracer autoradiography. The distribution of 67Ga in inflammatory tissue was similar to that of 131I-HSA and 99mTc-HSA, which were applied as an index to the plasma element. These results showed that the capillary permeability of plasma from blood vessels in the inflammatory tissue increases, and this causes the 67Ga-uptake.
Int J Rad Appl Instrum A 1988
PMID:Distribution of 67Ga-citrate in abscess-induced rat by quantitative whole body autoradiography. 284 97

A bifunctional chelating agent (BFCA) based on a macrocyclic amine, cyclam, was used to form specifically 99mTc labeled rabbit-anti-HSA-antibodies. This study demonstrates the feasibility of forming a highly stable cyclam-based 99mTc-BFCA with its subsequent conjugation to antibodies.
Int J Rad Appl Instrum B 1987
PMID:The production of 99mTc-labeled conjugated antibodies using a cyclam-based bifunctional chelating agent. 342 38

DTPA N-hydroxysuccinimide pentaester (DHSE) can be used as an alternative to bicyclic anhydride for coupling proteins with DTPA. However, in-vitro analysis of labeled proteins coupled with DHSE compared to bicyclic anhydride showed more high molecular weight product and less serum stability. We studied the magnitude of these differences in vivo by coupling HSA and IgG with DTPA using both methods, labeling with 111In, and analyzing the biodistribution in mice. The results of this analysis showed comparable activity in the liver, kidneys and blood.
Int J Rad Appl Instrum B 1986
PMID:Comparison of two methods of labeling proteins with 111In. 353 83

The HSA-binding of 99mTc incubated as 99mTc(113Sn)-MDP depends in vitro on the presence of competing anions normally present in plasma and on the MDP and Tc concentration, but is independent of the Sn concentration. The HSA-binding of 113Sn depends on the MDP and Sn concentration; not on the Tc concentration. 99mTc(Sn)-MDP binds to HSA as a unit. The binding of 99mTc(Sn)-MDP to plasma proteins in vivo is much lower as calculated from in vitro experiments because of competition between 99mTc(Sn)-MDP and endogenous anions for the same binding-sites.
Int J Rad Appl Instrum B 1987
PMID:Binding of 99mTc(113Sn)-MDP to human serum albumin. The influence of various technetium, tin, and MDP concentrations. 359 13

The conjugation of a model antibody (rabbit-anti-HSA-IgG) with a functionalized derivative of cyclam (1-(3-aminopropyl)-4-methyl-1,4,8,11-tetraazacyclotetradecane) is reported. Coupling of this derivative to the antibodies was accomplished using commercially available heterobifunctional coupling agents. The conjugation technique produced minimal effects on the antibody binding activity. 64Cu complexes with this cyclam derivative have excellent stability in human serum and aqueous solutions containing 1 mM EDTA. The high stability of these Cu-complexes suggests that this system, or other analogous systems, may be useful for production of stable 67Cu-immunotherapeutic agents.
Int J Rad Appl Instrum B 1987
PMID:Labeling of antibodies with 64Cu using a conjugate containing a macrocyclic amine chelating agent. 366 12