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Biomedical subjects

R L Guyer

Publications and source records attributed to R L Guyer.

14 recordsLinked to original sources
PubMed2000

Trials with errors--preserving the integrity of clinical trials.

The crucial final test of medical research is the clinical trial, which determines whether a drug or discovery really is an effective therapy. All people who participate in clinical trials--researchers, sponsors, volunteers, analysts, reviewers, overseers, others--have opportunities to strengthen or weaken the integrity of the trial system by their behavior. Medical research is now officially married to business, and "profitable" connotes something different to each partner. Only if research and business can profit in parallel will the alliance succeed. Every person who is involved in the medical research business faces temptations and must choose how to react. Each has power and must choose how to wield it. Several centuries before this marriage, the Englishman Izaak Walton noted that "Health is...a blessing that money cannot buy."

Clinical Trials as Topic↗
PubMed1981

A quantitative radioimmunoassay for DNA-binding antibodies.

An RIA is described for the measurement of serum immunoglobulins capable of binding to double-stranded or single-stranded DNA. DNA attached to Sephadex G-50 by UV irradiation was used as a solid-phase immunoabsorbent for DNA-binding proteins from serum. GAH IgG (125l-labeled) and GAH IgM (131l-labeled) were used to detect the human immunoglobulins bound onto the washed DNA-Sephadex. The quantities of immunoglobulins bound were determined by comparison with a standard curve constructed by dilution of a plasma from a SLE patient containing known amount of bound, DNA-specific IgM and IgG. Another RIA was employed for measuring levels of IgG and IgM. In combination with measurements of the total serum IgM and IgG, the RIA allowed for the determination of the fraction of the total serum IgM or IgG that was specific for double- or single-stranded DNA. For pool of normal human sera the quantities were as follows: 0.04% of the total IgM and 0.001% of the total IgG bound double-stranded DNA; 0.22% of the total IgM and 0.05% of the total IgG bound single-stranded DNA. This capability is important because information regarding the quantitative measurement of antibodies to DNA and their class determination may be of significance in monitoring the status of subjects with SLE.

Adult↗
PubMed1979

Complement fixation by model immune complexes free in solution and bound onto cell surfaces.

Immunoglobin (IgG) molecules with anti-2,4-dinitrophenyl activity were covalently cross-linked by using three cross-linking reagents. The resulting oligomers were separated into monomer, dimer, trimer, and heavy fractions. These stable assemblages of IgG molecules were capable of fixing dilute whole guinea pig complement in solution. When oligomers were further aggregated noncovalently into larger complexes, all were able to fix complement. Radioiodinated oligomers were attached to 2,4,6,-trinitrophenylsulfonic acid treated sheep red blood cells (N3ph-SRBC), and the number of bound molecules was determined from the cell-associated radioactivity. Complement-mediated lysis of N3ph-SRBC was then assayed over a range of levels of bound protein and at increasing concentrations of complement. The lytic efficiencies of all oligomers increased with the number of bound molecules, with complement concentration, with hapten density on N3ph-SRBC, and with oligomer size. The results suggest that two adjacent IgG molecules may not serve as a unit signal for triggering the complement cascade, but instead, initiation occurs with increasing efficiency as the size of cell-bound IgG clusters increases.

Animals↗
PubMed1976

Immunoglobulin binding by mouse intestinal epithelial cell receptors.

The IgG receptors involved in transporting maternal antibodies to the blood stream of the young mouse were studied by feeding internally labeled mouse myeloma proteins and enzymatically generated specific fragments of these proteins. The data obtained from competition experiments showed the following: 1) intestinal receptors have a single specificity which is directed against IgG Fc determinants; 2) IgG subclass proteins differ in their affinities for the receptors and thus have similar but not identical Fc recognition sites; 3) the order of affinities of the IgG subclass proteins for the receptors correlates with the relative concentrations of the four subclass proteins in mouse milk; and 4) several subfractions of the Fc fragment were inactive in binding to the receptors. In many of their properties the intestinal receptors resemble the Fc receptors on other cell types, but they are apparently unique in their ability to bind tightly non-aggregated IgG molecules.

Absorption↗