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Biomedical subjects

J E Butler

Publications and source records attributed to J E Butler.

67 records · Page 4Linked to original sources
PubMed1978

Amplification of the enzyme-linked immunosorbent assay (ELISA) in the detection of class-specific antibodies.

A modification of the standard enzyme-linked immunosorbent assay (ELISA) is described which circumvents the requirement for specifically purified antibodies from which antibody-enzyme complexes are made. The assay utilizes the principle of a soluble anti-alkaline phosphatase immune complex (AP-A-AP) and has been called the amplified ELISA. Methods for preparing and evidence for the specificity of rabbit anti-rat gamma-FC, IgM (mu) and IgA (alpha) are presented. These reagents are used to measure anti-DNP antibodies belonging to classes IgG, IgM and IgA in rat serum. Using antiglobulin and anti-enzyme reagents prepared in guinea pigs, anti-ovalbumin antibodies are measured in rabbit serum. Titration curves are similar when the amplified ELISA is compared to the standard ELISA. A change in slope suggesting an effect of saturation of antigen sites, occurs at the same input antibody concentration for both assays. Determination of the anti-DNP concentration of unknown sera by extrapopulation from titration graphs of a known serum suggests that the value is overestimated, i.e., amplified when the amplified ELISA is used. In addition, the amplified ELISA has an improved ability to detect low levels of antibody. Evidence is presented which illustrates how the use of optimally conjugated DNP-proteins, age of conjugates, and optimal dilutions of secondary antiglobulins and the AP-A-AP reduce non-specific binding in the amplified ELISA. The amplified ELISA is capable of detecting 2.4 ng of antibody to ovalbumin in a one: one million dilution of rabbit serum with high reproducibility and low background.

Animals↗
PubMed1978

Incomplete inhibition of the immunoglobulin G-binding behavior of nitrated protein A.

Nitration of protein A with tetranitromethane incompletely blocks its Fc-binding ability for immunoglobulin G when measured by more sensitive methods of immunoprecipitation and when tested in the enzyme-linked immunosorbent assay. In addition, binding of protein A and blockage by nitration is heterogeneous and depends on the species origin of the immunoglobulin G.

Animals↗
PubMed1978

Evaluation of enzyme-linked immunosorbent assay for quantitation by subclass for bovine antibodies.

The enzyme-linked immunosorbent assay (ELISA) was evaluated for use in the quantitative measurement of bovine immunoglobulin IgG1 and IgG2 antibodies. A method for standardization was devised in which IgG1 or IgG2 was directly adsorbed to polystyrene tubes and the actual degree of binding was calculated by using different input amounts of 125I-labeled IgG1 or IgG2. Values for quantity of IgG1 antibodies to human serum albumin were only slightly higher when measured by the ELISA than when measured by quantitative precipitation although the value measured by the ELISA for IgG2 antibodies was twice that determined by quantitative precipitation. This discrepancy could result from conjugate cross reactivity, differences in affinity between antibodies of the 2 subclasses, or the occurrence of IgG2 nonprecipitating antibodies. The danger of overlooking subclass anti-globulin cross reactivity because of the failure to detect it by immunoprecipitation, also is illustrated. In addition, only enzyme-antibody conjugates prepared with specifically purified antibodies were effective, and reproducibility of individual data points required that 4 replicate determinations be performed. Advantages, pitfalls, and limitations of the ELISA are discussed.

Animals↗
PubMed1976

Tickborne oculoglandular tularemia: case report and review of seasonal and vectorial associations in 106 cases.

A patient acquired tickborne oculoglandular tularemia in early summer in rural Virginia. Tick exposure may be a clue to the diagnosis of tularemia in the eastern as well as the western United States, especially in summer months. A review of the experience with tularemia in Virginia for the last 13 years shows a bimodal seasonal incidence of tularemia with an associated vector exposure in 77.4% of 106 cases. The majority of cases occurring during winter months have been associated with rabbit exposure, while those in summer months are often associated with tick exposure.

Aged↗
PubMed1976

Two immunochemically and physicochemically distinct secretory components from rat exocrine secretion.

Two proteins were isolated from rat milk by using ion-exchange and gel filtration chromatography and shown to be secretory components by the criteria of: a) occurrence as free proteins in exocrine secretions, as well as bound to exocrine IgA while absent from serum and serum IgA, b) immunohistochemical localization in the epithelial cells of the gut, c) dissociability from and in vitro binding to 11 S SIgA, d) cross-reactivity with antisera to mouse and bovine secretory components, and e) significant peptide homology with bovine secretory component. The secretory components were immunochemically and physicochemically distinct as shown by: a) the lack of cross-reactivity between their specific antisera and differential reactivity with anti-bovine FSC and anti-mouse SC, b) different electrophoretic mobilities, c) DEAE elution profiles, d) carbohydrate contents, e) molecular weights, and f) apparent polypeptide chain constitution. Another interesting difference in the two is that only one of the components dissociates spontaneously from SIgA. Possible functions of two secretory components are discussed.

Animals↗
PubMedDate not supplied

The immunochemistry of sandwich ELISAs--V. The capture antibody performance of polyclonal antibody-enriched fractions prepared by various methods.

Studies compare the performance of antibody-enriched serum fractions prepared by various methods, when adsorbed on polystyrene microtiter wells as capture antibodies (CAbs) and tested against multivalent antigens. The criteria of performance in the RIA used included antigen capture capacity (AgCC) and the nmol of functional capture sites per microtiter well (CAbt). Affinity purified polyclonal (pAb) and monoclonal antibodies (mAb) were employed as reference CAbs. AgCC was highest for enriched fractions prepared using caprylic acid and a high-pressure SpG affinity column. The performance of capture antibodies is expressed by an equation which was empirically derived and experimentally tested; CAbt x AgCC/ng adsorbed IgG. In terms of this parameter, CAb-enriched fractions prepared with caprylic acid performed best. The data reported also provide insight into solid-phase ligand immunochemistry. Adsorbed polyclonal CAb performed with remarkable homogeneity in percent bound and in Scatchard plots. Values obtained for CAbt from Steward-Petty plots were directly correlated with the length of the LBR of log-log percent bound plots but indicated that less than 10% of the potential capture sites of polyclonal CAbs remained functional after adsorption; mAb showed a more serious loss of activity. The loss of CAbt was a general phenomenon for all preparations tested although relative to their antibody content, certain antibody-enriched fractions retained a higher proportion of CAbt than their affinity-purified counterparts. Comparative studies in which the activity of adsorbed mAb and pAb was compared to the same antibodies immobilized by a non-adsorptive procedure, indicated that adsorbed CAbs also express lower affinity. The studies we report offer a single parameter criterium for comparatively evaluating CAb performance while simultaneously revealing the need to develop immobilization procedures that can preserve CAbt and antibody affinity so that immunoassays with wide dynamic ranges and high AgCC can be developed without waste of antibody.

Adsorption↗
PubMedDate not supplied

The appearance of the tarsal navicular after posteromedial release for clubfoot.

Sixty-one idiopathic clubfeet in 46 patients of an older population were treated by one-stage posteromedial release. Follow-up roentgenograms revealed dorsal subluxation of the tarsal navicular in 43% of the clubfeet. This abnormality is probably due to both closed manipulation and casting, and improper positioning of the navicular during posteromedial release. However, dorsal navicular subluxation did not adversely affect the results of treatment observed over the follow-up period that averaged nearly 6 1/2 years. Medial subluxation of the navicular was associated with unsatisfactory results, whereas a centrally located or laterally subluxed navicular generally produced good or excellent results. Other abnormalities of the navicular noted included wedging and avascular necrosis. The long-term consequences of these various abnormalities of the roentgenographic appearance and position of the navicular are not known.

Adolescent↗
PubMedDate not supplied

Abduction injuries of the distal femoral epiphysis.

Based on a follow-up study of 15 distal femoral epiphyseal fractures, the following conclusions are drawn: Closed reduction with cross pinning of the distal femoral epiphysis provided slightly better results and prevented loss of reduction; angulation deformity, requiring corrective surgery occurred in four patients, two of whom had initial anatomical reductions; significant leg length inequality was not seen; abduction injuries of the distal femoral epiphysis are not uncommon in teenage football players.

Adolescent↗