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Biomedical subjects

R C Williams

Publications and source records attributed to R C Williams.

At least 397 records · Page 22Linked to original sources
PubMed1979

Crossed radioimmunoelectrophoresis for the analysis of lymphocyte surface antigens.

A sensitive crossed radioimmunoelectrophoreses technique is described as a model tool for studying lymphocyte surface antigens, using Triton X-100 solubilized sufface radiolabeled human peripheral blood lymphocytes as the antigen source and experimental antiserum produced by hyperimmunization of rabbits as the antibody source. The technique seems to have potential for qualitative as well as quantitative analyses of lymphocyte surface antigens.

Absorption↗
PubMed1979

Characterization of cyanobacterial phycobilisomes in zwitterionic detergents.

Properties of cyanobacterial phycobilisomes (from Synechococcus spp. 6301 and 6312 and Synechocystis sp. 6701) prepared in the presence of two different zwitterionic detergents were compared to those of phycobilisomes detached from membranes with the nonionic detergent Triton X-100 and then freed from Triton by sedimentation through high-salt sucrose density gradients. The absorption spectra, polypeptide composition, and ultrastructure of phycobilisomes were independent of the detergent used during the preparation. Phycobilisomes from certain cyanobacteria aggregated in the absence of detergent. Such aggregation was not seen in preparations containing zwitterionic detergents. Aggregation of phycobilisomes led to a partial quenching of their fluorescence. Electron microscopy showed the three types of phycobilisomes to have a hemi-disc appearance, although their detailed structures were quite different.

Journal Article↗
PubMed1979

Cyclic nucleotide phosphodiesterase activity in 10-nm filaments and microtubule preparations from bovine brain.

Cyclic nucleotide phosphodiesterase activity (3':5'-cyclic-AMP 5'-nucleotidohydrolase, EC 3.1.4.17), which is activatable by Ca(2+)-dependent regulator protein (CDR), has been identified in cycled microtubule preparations from bovine brain. By using various methods to fractionate the microtubule preparation into subfractions (e.g., phosphocellulose chromatography to obtain purified 6S tubulin and soluble microtubule-associated proteins, and gel exclusion chromatography on Bio-Gel A-150m to obtain 10-nm filaments), we found that all the fractions exhibited some enzymic activity, but that most of the phosphodiesterase activity was localized in the 10-nm filament fraction. By using cyclic GMP as substrate, a specific activity of 921 +/- 168 pmol/mg of filament protein.min was determined. Also, 10-nm filaments were prepared directly from brain homogenates by differential centrifugation and gel exclusion chromatography. This fraction also contained phosphodiesterase activity but of slightly lower specific activity (752 +/- 9 pmol/mg of protein.min). The filament-associated enzymic activity was stable during storage (-70 degrees C) and to several salt extractions at moderate ionic strength (0.5 M); the latter finding indicates that the phosphodiesterase is not adsorbed to the filaments via nonspecific electrostatic interactions. Although a chelating agent was present in the initial homogenization buffer and generally in all buffers used in preparing fractions, an activator of a smooth muscle phosphodiesterase was released upon boiling the 10-nm filaments. This activator obtained in the boiled supernatant was Ca(2+)-sensitive, trifluoperazine-sensitive, and stimulated smooth muscle phosphodiesterase to nearly the same extent as purified (exogenous) CDR; thus, it probably represents filament-associated CDR.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1979

Rheumatoid arthritis.

Why self-perpetuating joint destruction is intermittent in some patients and unrelenting in others remains largely unknown, but progress has been made in identifying the different types of clinical course and tailoring specific treatment regimens for each.

Adrenal Cortex Hormones↗
PubMed1979

Gn allotypes in mother-father-cord trios. A selective transfer of autologous, fetal IgG to the mother.

When tested at a standard dilution (1:30), mother-cord Gm phenotypes are identical. A more sensitive assay reveals that the fetus does possess paternal antigen, that is, does produce small amounts of autologous IgG. The paternal antigens, in both the mother and the cord plasma, appear in a mosaic, one that suggests the fetus has the ability to selectively transfer his own IgG subclasses to the mother.

Antigens↗
PubMed1979

Circulating immune complexes in Lyme arthritis. Detection by the 125I-C1q binding, C1q solid phase, and Raji cell assays.

We have found immunoglobulin (Ig) G-containing material consistent with immune complexes in the sera of patients with Lyme arthritis. It was detected in 29 of 55 sera (55%) from 31 patients by at least one of three assays: (125)I-C1q binding, C1q solid phase, or Raji cell. The presence of reactive material correlated with clinical aspects of disease activity; it was found early in the illness, was most prominent in sera from the sickest patients, was infrequent during remissions, and often fluctuated in parallel with changes in clinical status. The results in the two C1q assays showed a strong positive correlation (P<0.001). They were each elevated in 45% of the sera and were usually concordant (85%). In contrast, the Raji cell assay was less frequently positive and often discordant with the C1q assays. In sucrose density gradients, putative circulating immune complexes sedimented near 19S; they, too, were detected best by the two assays based on C1q binding. An additional 7S component was found in some sera by the (125)I-C1q binding assay. Serum complement was often above the range of normal in patients with mild disease and normal in patients with severe disease but did not correlate significantly with levels of circulating immune complexes. IgM and IgG rheumatoid factors were not detectable. These findings support a role for immune complexes in the pathogenesis of Lyme arthritis. Their measurement, by either the (125)I-C1q binding assay or by the C1q solid phase assay, often provides a sensitive index of disease activity. Moreover, the complexes are likely sources of disease-related antigens for further study of this new disorder.

Adolescent↗
PubMed1979

Studies of human cord blood and adult lymphocyte interactions with in vitro immunoglobulin production.

Newborns are unable to produce normal amounts of immunoglobulin despite the presence of circulating lymphocytes with surface immunoglobin (Ig). This study was designed to examine the cellular basis of such impaired Ig synthesis in the newborn infant. An in vitro assay for IgG and IgM synthesis was employed which measured the Ig present in the supernates of pokeweed mitogen-stimulated cord blood and/or adult peripheral mononuclear cells (MNC). Results were as follows: (a) the addition of cord blood MNC to adult MNC suppressed both normal IgG and IgM production; (b) addition of a suspension of adult thymus-derived (T) cells to cord bone marrow-derived (B) cells did not enhance the production of Ig; (c) the addition of cord T cells to adult B cells did not enhance normal Ig production but did significantly depress IgM and IgG synthesis; and (d) irradiation of cord T cells with 2,000 rads removed the suppressive effect of cord T cells on adult MNC. A similar reversal of the suppressive effect exerted by cord MNC was also seen in the presence of 10 microM of hydrocortisone. It appears that the inability of newborn infants to make normal amounts of Ig is a result of a combined B-cell defect and the presence of a steroid-sensitive and radiosensitive suppressor cord T cell.

Adult↗