PubMed Health⌕ Search

Biomedical subjects

M Adamczyk

Publications and source records attributed to M Adamczyk.

At least 73 records · Page 4Linked to original sources
PubMed1993

Immunoassay reagents for psychoactive drugs. Part 3. Removal of phenothiazine interferences in the quantification of tricyclic antidepressants.

Phenothiazines and their metabolites are known to interfere in the quantification of tricyclic antidepressants (TCAs). A method for selective chemical modification of phenothiazines by chloramine-T in the presence of TCAs is described. This method allows for accurate quantification of the TCA analyte in a serum sample without interference from the modified phenothiazine.

Antidepressive Agents, Tricyclic↗
PubMed1992

Kinetics of haloperidol binding to monoclonal antibodies as measured by direct fluorescence quenching.

Monoclonal antibodies which bind small neurogenic ligands may mimic certain aspects of the stereospecific binding present in the natural biological receptor, and may prove useful in designing engineered protein receptors, provided their interactions are correctly understood. We report here the kinetic and equilibrium characteristics of ligand-antibody complexes of haloperidol, a dopaminergic antagonist, with three of its monoclonal antibodies as studied by fluorescence quenching techniques. These antibodies possessed moderate to high affinity constants, ranging from 10(5) to 10(9) M-1, and caused fluorescence quenching of a fluorescein-labeled haloperidol as well as quenching (40-60%) of the internal tryptophan fluorescence. The dissociation rates of the ligand from the complexes were measured at different conditions of temperature, pH and ionic strength. The results provide important information regarding the kinetic and thermodynamic parameters of the binding pockets of these antibodies.

Antibodies, Monoclonal↗
PubMed1992

Kinetic and energetic parameters of imipramine binding to monoclonal antibodies as measured by fluorescence spectroscopy.

Monoclonal antibodies which bind small drugs are useful for the study of the interactive forces involved in antibody-ligand complexation. Detailed understanding of these supramolecular forces requires a careful examination of structural and thermodynamic parameters of the interacting molecules. Fluorescence spectroscopy techniques are very useful in this regard. We report here, the kinetic and energetic parameters of four monoclonal antibodies made against the tricyclic antidepressant imipramine. These monoclonal antibodies were found to possess high to very high binding affinity constants, ranging from 10(7) to 10(10) M-1, and caused fluorescence quenching or enhancement of a fluorescein labelled imipramine. The dissociation rates of the fluorescent ligand from the complexes were measured at different temperatures in order to provide some insight regarding the kinetic and energetic (thermodynamic) parameters of the antibody-ligand binding interactions.

Animals↗
PubMed1989

Fluorescence polarization immunoassay of urinary 5-hydroxy-3-indoleacetic acid.

Fluorescence polarization immunoassay of 5-hydroxy-3-indoleacetic acid in urine is described and compared with liquid chromatography (electrochemical detection) and colorimetry. Reports of in-house performance data and results of clinical trials are included to emphasize the usefulness of the assay for routine work.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Linker-mediated modulation of the chemiluminescent signal from N(10)-(3-Sulfopropyl)-N-sulfonylacridinium-9-carboxamide tracers.

Four chemiluminescent N-sulfonylacridinium-9-carboxamide active esters (17-20) were prepared from the corresponding acids and coupled to both of the aminated phenobarbital (13) and N-(6-aminohexyl)phenytoin (16) haptens. The level of signal produced by chemiluminescent N-sulfonylacridinium-9-carboxamide phenobarbital and phenytoin tracers in a solid-phase immunoassay format was found to be modulated by at least 20-fold by the judicious choice of the reactive acridinium-hapten linking group.

Acridines↗
PubMedDate not supplied

A chemoselective method for site-specific immobilization of peptides via aminooxy group.

Site-specific modification of peptides and proteins is an important area of basic research for preparation of well-defined biosensors and probes. The unique properties of aminooxy group present an opportunity for chemoselective site-specific immobilization of peptides to prepare well-defined biosensors. We have prepared FLAG peptide derivatives containing L-epsilon-aminooxylysine (L-epsilon-AOLys, 1a) and L-lysine units in their sequence at the C- and N-terminals via solid-phase synthesis. Site-specific modification of peptides through aminooxy group was demonstrated in the preparation of biosensors and selective conjugation in the preparation of biotinylated probes. Effect of the incorporation of L-epsilon-AOLys (1a) into the peptide sequence and its subsequent labeling on the FLAG epitopic character was measured using a surface plasmon resonance detector. It was found that incorporation of L-epsilon-AOLys (1a) into the FLAG peptide and site-specific immobilization through aminooxy group preserved the integrity of FLAG epitope.

Antibodies, Monoclonal↗
PubMedDate not supplied

Design of acridinium-9-carboxamides and anti-acridinium antibodies for chemiluminescent signal enhancement.

A novel system of signal enhancement is presented in which every labeled antibody is capable of generating a signal. Three chemiluminescent acridinium-9-carboxamide haptens (1, 2, and 3) which incorporated differences in charge and location of the linker were designed and synthesized. Anti-acridinium polyclonal antibodies for each hapten were screened using surface plasmon resonance instrumentation to determine specificity for each hapten. Anti-acridinium 2 antibodies were found to be non-cross-reactive to acridinium 1. This property was exploited to design secondary antibody conjugates which would bind to primary antibodies labeled with 2 yet could still be labeled with the structurally similar acridinium 1. Consequently, both layers contributed to the overall chemiluminescent signal. This format is an advance over other signal amplification formats which employ non-signal-generating, labeled antibodies to construct multilayered systems.

Acridines↗
PubMedDate not supplied

Immunoassay reagents for thyroid testing. 1. Synthesis of thyroxine conjugates.

Immunoreagents were designed to improve the performance of a commercial fluorescent polarization immunoassay for thyroxine. The thyroxine immunogen was prepared by selective coupling of N-acetyl-L-thyroxine to BSA via an aminocaproic acid spacer arm. The fluorescent tracer was prepared by a multistep reaction sequence which relied on extensive use of orthogonal protecting groups.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Characterization of protein-hapten conjugates. 1. Matrix-assisted laser desorption ionization mass spectrometry of immuno BSA-hapten conjugates and comparison with other characterization methods.

Several different low molecular weight haptens were conjugated to BSA to produce immunogens useful for antibody development. The extent of BSA modification due to covalent attachment of hapten was estimated by matrix-assisted laser desorption ionization mass spectrometry. The average number of hapten incorporated to immunogen was determined from the difference in the measured molecular weights of the conjugate from nonmodified BSA. The results from mass spectrometry were compared with results obtained from other more traditional methods of immunogen characterization (UV analysis, trinitrobenzenesulfonic acid titrations, and gel electrophoresis). In each case we were able to calculate the average number of hapten covalently bound to BSA for each synthetically prepared immunogen using matrix-assisted laser desorption ionization mass spectrometry. The other methods presented limitations in certain cases.

Electrophoresis, Polyacrylamide Gel↗
PubMedDate not supplied

Characterization of protein-hapten conjugates. 2. Electrospray mass spectrometry of bovine serum albumin-hapten conjugates.

Fifteen hapten-bovine serum albumin (BSA) conjugates were prepared from five commercially available activated haptens. Each hapten was coupled to BSA at three different ratios. The conjugates were characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and two mass spectrometry (MS) methods: matrix-assisted laser desorption ionization (MALDI) and liquid chromatography-electrospray ionization (LC-ESI). SDS-PAGE was useful in detecting protein cross-linking, but not assessing hapten density. MALDI-MS and LC-ESI-MS gave comparable qualitative results, but LC-ESI-MS provided a clearer representation of the distribution of hapten-protein species present in the conjugates. Conjugate species substitute with up to 25 haptens per BSA were recorded by LC-ESI-MS.

Animals↗
PubMedDate not supplied

Preparation of succinimidyl and pentafluorophenyl active esters of 5- and 6-carboxyfluorescein.

A mixture of 5- and 6-carboxyfluorescein was activated with 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride in the presence of either N-hydroxysuccinimide or pentafluorophenol to give the corresponding succinimidyl and pentafluorophenyl esters. The regioisomeric mixtures were separated to give the 5- and 6-succinimidyl and pentafluorophenyl active esters in > 98% purity.

Esterification↗
PubMedDate not supplied

Immunoassay reagents for thyroid testing. 2. Binding properties and energetic parameters of a T4 monoclonal antibody and its Fab fragment with a library of thyroxine analog biosensors using surface plasmon resonance.

A library of 16 thyroxine analog biosensors were prepared for use on the BIAcore surface plasmon resonance instrument. An anti-thyroxine monoclonal antibody and its Fab fragment were tested with each biosensor to generate the association and dissociation rate constants, equilibrium association constants, and Gibbs free energy values for characterizing the binding event.

Animals↗
PubMedDate not supplied

Synthesis of conjugates for a barbiturate screening assay.

Novel derivatives of barbiturates functionalized with free carboxylic acids were designed and synthesized. Coupling of 5-cyclopentyl-5-carboxycrotylbarbituric acid via its active ester to an aminofluorescein derivative produced a fluorescent tracer. Conjugation of the 5-cyclopentenyl-5-carboxyethylbarbituric acid via its mixed anhydride to thyroglobulin allowed for subsequent development of a polyclonal antibody which was evaluated for binding in a fluorescence polarization immunoassay format with various barbiturates. The binding studies showed good cross-reactivity of a variety of barbiturates containing both aromatic and aliphatic 5-substituents with the tested antisera. The relationship between the immunogen architecture, the chemical structure of the binding analytes, and the characteristics of the antisera is also presented.

Animals↗
PubMedDate not supplied

Electrospray mass spectrometry of alpha and beta chains of selected hemoglobins and their TNBA and TNB conjugates.

The molecular weights of alpha and beta hemoglobin chains from 15 different vertebrate animal sources and 2 common human variants were determined by electrospray mass spectrometry and compared to the calculated masses based on published amino acid sequences. Conjugates were prepared for 14 of the globins using 2 traditional colorimetric derivatizing reagents, 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) and trinitrobenzenesulfonic acid (TNBS), and the mass of each conjugate was determined by mass spectrometry.

Animals↗
PubMedDate not supplied

Immunoassay reagents for thyroid testing. 3. Determination of the solution binding affinities of a T4 monoclonal antibody Fab fragment for a library of thyroxine analogs using surface plasmon resonance.

A library of thyroxine analogs and tracers was prepared, and their solution binding affinities for an anti-T4 Fab fragment were determined using a single high-density L-T4 biosensor surface in a BIAcore surface plasmon resonance instrument. The high-density L-T4 analog biosensor was calibrated by determination of the initial binding rate was of known concentrations of free anti-T4 Fab fragment in solution to the biosensor surface. A range of individual thyroxine analog and tracer concentrations was subsequently mixed with a fixed concentration of anti-T4 Fab fragment. The concentration of free anti-T4 Fab fragment in each solution at equilibrium was determined, and the equilibrium dissociation constant (KD) for each case was derived. The KD values determined in solution are compared to values determined by a direct kinetic analysis on the BIAcore instrument using individual biosensor surfaces.

Acridines↗
PubMedDate not supplied

Synthesis of 6beta-[(2'-Aminoethyl)carboxamidomethyl]estradiol and preparation of estradiol probes.

Reformatsky reaction of 3, 17beta-bis[(2-trimethylsilyl)ethoxymethyl]-1,3, 5(10)-estratrien-6-one (2) with bromoethyl acetate and zinc gave the ester (3) in 60% yield which upon treatment with methanesulfonyl chloride in pyridine afforded the olefinic esters (4 and 5) as an endo and exo mixture (67:33 ratio) in 81% yield. Hydrolysis of the SEM protective groups in compounds 4 and 5 followed by hydrogenation of the resulting hydroxy compounds 6 and 7 using 10% Pd/C afforded an epimeric mixture (beta:alpha = 79:21) of 6-[(ethoxycarbonyl)methyl]estradiol (8a and 8b) in 95% yield. Hydrolysis of the ethyl esters (8a and 8b) using sodium hydroxide gave the acid (9a and 9b) in 81% yield. The epimeric mixture of acids (9a and 9b) was activated, treated with tert-butyl-N-(2-aminoethyl)carbamate (10), and purified by HPLC to afford 6beta-[[[(2-tert-butoxycarbonyl)amino]ethyl]carboxamidomethyl] estradiol (11) in 39% yield as the major isomer. Hydrolysis of the BOC group in compound 11 using TFA afforded the desired 6beta-[(2-aminoethyl)carboxamidomethyl]estradiol 12 in 50% yield. The biotinylated estradiol probe 14, fluorescent probe 16, and chemiluminescent probe 18 were prepared from 6beta-[(2'-aminoethyl)carboxamidomethyl]estradiol (12) and the corresponding biotin, 5-carboxyfluorescein, and 10-(3-sulfopropyl)-N-tosyl-N-(3-carboxypropyl)acridinium-9-carboxamide N-succinimidyl esters (13, 15, and 17) in 65-74% yield and 99% purity.

Biotinylation↗