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C A Wolfe

Publications and source records attributed to C A Wolfe.

8 recordsLinked to original sources
PubMed1995

Studies on the rate and control of antibody oxidation by periodate.

The oxidation of antibody carbohydrate residues by periodate is a common approach for the site-specific immobilization or modification of antibodies for use in various bioanalytical methods. This study examined the time dependence of this oxidation process under a variety of pH, temperature, and concentration conditions. Polyclonal rabbit immunoglobulin G (IgG)was used as the model system for these studies. Flow-injection analysis and a hydrazide label (Lucifer yellow CH) were used to monitor the progress of the oxidation reaction. It was found that the number of oxidized sites that were available for labeling could be varied between one and eight groups per antibody by adjusting the time, pH, periodate concentration, or reaction temperature. In each case, most of these groups were produced during the first 30-60 min of the reaction. A comparison was made between these results and those of previous studies that have examined the effects of periodate treatment on amino acid residues and antibody activity. From this work, general guidelines were developed for the control and optimization of antibody oxidation for use with assays that require either high or low levels of antibody modification.

Animals↗
PubMed1994

Automated determination of antibody oxidation using flow injection analysis.

The oxidation of antibody carbohydrate residues is a common approach used for site-specific antibody immobilization or modification. In this study a flow injection analysis system (FIA) was developed for monitoring antibody oxidation. Antibodies were oxidized with periodate and the resulting aldehyde groups were labeled with Lucifer yellow CH (LyCH). The labeled antibodies were then injected onto an FIA system where the amount of LyCH label was determined by absorbance measurements at 428 nm and the amount of antibody was determined using an on-line bicinchoninic acid protein assay. The analysis time was 2 min per 20 microliters sample injection. The limits of detection for rabbit immunoglobulin G (IgG) and LyCH were 1 x 10(-8) and 4 x 10(-7) M, respectively. The dynamic ranges for IgG and LyCH extended to 2 x 10(-5) and 7 x 10(-3) M. The within-run precision was +/- 5% or less for both analytes. Studies with known LyCH/antibody mixtures indicated that the FIA system had greater accuracy than manual methods at high LyCH levels. One specific application studied for this system was its use in monitoring the time course of periodate-antibody oxidation.

Animals↗
PubMed1994

Optimization of oxidized antibody labeling with lucifer yellow CH.

The oxidation of antibody carbohydrate residues is a common approach used for the site-specific immobilization or modification of antibodies. One way of following this oxidation process is to label the resulting aldehyde groups with a dye such as Lucifer yellow CH (LyCH). This study examined the optimum conditions for preparing and purifying antibody-LyCH conjugates. A 250-fold excess of LyCH reacted with antibody at pH 6.5 for two or more hours gave maximum labeling. Nonreacted LyCH could be effectively removed by passing the labeled antibody through a size exclusion column, followed by one or two dialysis cycles. The LyCH antibody conjugates were found to be stable for at least three weeks when stored in pH 7.4 phosphate buffer.

Animals↗
PubMed1991

Doctor at "The Cross".

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Acquired Immunodeficiency Syndrome↗
PubMed1988

An unusual cause of massive pleural effusion in pregnancy.

A 40 year old woman at 30 weeks of her eighth pregnancy presented with acute onset of dyspnoea and a large left pleural effusion after the onset of premature labour. A barium enema showed diaphragmatic rupture with intestinal contents in the thorax. Repair was accomplished through simultaneous left subcostal and thoracic incisions.

Adult↗
PubMed1972

Doctors' fees.

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Australia↗
PubMedDate not supplied

Development of a kinetic model to describe the effective rate of antibody oxidation by periodate.

The oxidation of antibody carbohydrate residues by periodate is a common approach used for site-specific antibody modification and immobilization. This study sought to develop a general kinetic model that could be used to describe the effective rate of this oxidation for process control. A detailed analysis of previous data collected for rabbit immunoglobulin G in the presence of excess periodate indicated that the reaction followed a pseudo-first-order mechanism in which two general classes of sites were being oxidized. The first class of sites was oxidized fairly rapidly (i.e., within 15-30 min), while the second class of sites reacted over the course of several hours. From these results, an equation was developed that gave a good fit under a variety of reaction conditions to the production of oxidized sites available for coupling with a hydrazide label. On the basis of this equation, data obtained at several periodate concentrations under the same pH and temperature conditions were used to estimate the apparent rate and equilibrium constants for the oxidation of each class of sites. The values obtained by using this approach could be used not only to predict the effective rate of oxidation at other periodate concentrations but also to provide information on the individual steps involved in the oxidation process.

Animals↗