Non-specific adsorption of serum proteins to Eupergit C (EC) and agarose during the process of immunoaffinity chromatography often leads to contamination of the specifically eluted antigens to be purified. This effect was studied by application of serum samples to a beta-mercaptoethanol-blocked EC (EC-beta ME) column followed by analysis of proteins eluted with various elution buffers. Inclusion of polyethylene glycol (PEG 400 or 1500) in the loading buffer reduced the non-specific adsorption of proteins to EC but had an adverse effect on agarose. Covalent attachment of amino-PEG to EC and to epoxy-activated Sepharose mimicked the effect of PEG in solution with EC and resulted in a marked reduction in non-specific adsorption of serum proteins. Inclusion of PEG in the loading buffer during immunopurification of a serum protein (immunoglobulin G) or seminal plasma protein (human decidua protein hDP71) resulted in a marked improvement in the purity of these proteins eluted from the respective columns by ammonium acetate (pH 10).

Adsorption↗

PubMed1990

Eupergit C as a carrier for high-performance liquid chromatographic-based immunopurification of antigens and antibodies.

An immunoaffinity purification system using C30N and C1Z Eupergit C beads was developed and optimized. Poly- and monoclonal antibodies were purified using immobilized antigens and antigens were purified using immobilized antibodies. Antigens were used that possess enzymic activities and the efficiency of antigen binding was determined from the enzymic activity of the matrix-bound immunocomplexes. High-performance immunoaffinity purification using Eupergit C beads proved to be highly specific, reproducible, free from protein leakage and possessed a low degree of non-specific adsorption of tissue proteins. These characteristics of the system were illustrated by the isolation of immunoglobulin G from serum and of human decidua proteins from the decidua tissue and from seminal plasma. These proteins were obtained at high purity in a single purification step, as shown by sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

Antibodies↗

PubMed1990

Anisotropic pressure dependence of Tc in single-crystal YBa2Cu3O7 via thermal expansion.

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Journal Article↗

PubMed1990

Oriented immobilization of periodate-oxidized monoclonal antibodies on amino and hydrazide derivatives of Eupergit C.

Amino and hydrazyno derivatives of Eupergit C were prepared by reaction of the beads with hexamethylene diamine (HMD) and adipic acid dihydrazide (ADH), respectively. Monoclonal antibodies (mAbs) against carboxypeptidase A (CPA) and horse radish peroxidase (HRP) were prepared, and those that did not inhibit the respective enzymatic activities were selected. The carbohydrate moieties of these antibodies were oxidized by reaction with sodium periodate and then coupled onto the modified beads. The oxidation and coupling reactions were optimized to achieve highly active matrix-conjugated antibodies. Thus, antibody-matrix conjugates that possessed antigen-binding activities close to the theoretical value of 2 mol antigen bound/mol immobilized antibody were obtained.

Acrylic Resins↗

PubMed1990

Adherence to colorectal cancer screening in an HMO population.

This study aimed to determine factors that influence fecal occult blood test performance in colorectal cancer screening. A random sample was selected of men and women ages 50 to 74 years of age who had been mailed a fecal occult blood testing kit in a screening program in fall 1986. One year after initial test mailing, sample group members (n = 504) were surveyed by telephone. Four months later, the survey sample received a second fecal occult blood test mailing. Multivariable analysis for subjects with validated past fecal occult blood test status (n = 322) revealed the past testing was positively associated with physician encouragement of screening, age, the belief that cancer is curable, perceived test efficacy, and strong intention to do testing. It also was discovered that persons who felt that they had little control over their health were more likely to have done past testing. Preliminary analysis of prospective adherence showed that the strongest statistically significant independent predictor was past test performance. Prospective adherence among past nontesters (n = 121) was associated with expressed commitment to do fecal occult blood testing and reported presence of colorectal cancer risk factors. Analysis of adherence among past testers (n = 201) revealed that belief in colorectal cancer curability and age were significant predictors. The findings reported here indicate that factors influencing adherence among past nontesters differ from those for past testers. Overall, these results suggest that to increase participation in colorectal cancer screening, physicians and other health professionals should (a) deliver educational messages that increase awareness of risk factors for colorectal cancer and curability of the disease, and (b) elicit from potential screenees a commitment to engage in recommended preventive behaviors. It may also be well to consider "tailoring" messages for past nontesters and past testers, respectively, by emphasizing colorectal cancer risk factors and highlighting curability.

Age Factors↗

PubMed1989

Differing effects of chromium(III) and chromium(VI) on nucleotides and DNA.

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Chemical Phenomena↗

PubMed1989

Nick translation studies on DNA strand breaks in pBR322 plasmid induced by different chromium species.

Single strand breaks are DNA defects caused by various chemicals. DNA strand breaks induced in vitro by chromium(VI) during the reduction of this chromium species with glutathione or hydrogen peroxide were examined. Using DNA agarose gel electrophoresis and a nick translation assay, strand breaks were detected only when chromium(VI) was reduced by hydrogen peroxide. The reduction of chromium(VI) by an excess of glutathione led to no alteration in the DNA agarose gel electrophoresis pattern of the double-stranded plasmid pBR322 DNA and in the nick translation assay, indicating that no strand breaks had occurred under these conditions. No strand breaks could be detected during the reduction by hydrogen peroxide after the addition of superoxide dismutase. This indicates that hydroxyl radicals from peroxochromium complexes may be a relevant reactive species involved in chromate genotoxicity.

Chromium↗