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Biomedical subjects

R C Williams

Publications and source records attributed to R C Williams.

At least 325 records · Page 18Linked to original sources
PubMed1982

Cutaneous manifestations of rheumatoid arthritis.

Rheumatoid arthritis is a systemic disease which can have multiple cutaneous manifestations. In particular, rheumatoid vasculitis may be difficult to diagnose because of the wide array of clinical presentations. Early recognition can assist the physician in diagnosis and in determination of the proper therapy. Every physician caring for patients with rheumatoid arthritis should be aware of these common dermatologic complications.

Adolescent↗
PubMed1982

Effect of tetracycline on gingival inflammation and alveolar bone resorption in beagles: an individual tooth by tooth analysis.

The effect of systemic tetracycline on gingival inflammation and alveolar bone resorption was studied in beagle dogs. Seventeen dogs were divided into three groups receiving either no treatment, 250 mg tetracycline HCl, or 500 mg tetracycline HCl daily. The severity of gingival inflammation and activity of alveolar bone resorption during a 6-month pretreatment period was compared to a 24-month treatment period for each individual tooth studied. In the first 12 months of treatment there was a significant decrease in the severity of gingival inflammation and the activity of alveolar bone loss in the tetracycline treated dogs. By 24 months of treatment increased gingival inflammation and rate of bone loss was evident in the treated dogs. In the untreated control dogs there was a statistically significant association between the severity of gingival inflammation and activity of alveolar bone resorption about the teeth studied. In the tetracycline treated dogs, no such association existed.

Alveolar Process↗
PubMed1982

Anti-Ia reactivity in sera from patients with systemic lupus erythematosus.

Antileukocyte antibodies in sera from patients with systemic lupus erythematosus (SLE) were characterized by determining cross-reacting specificies with the antigens defined by OKT3, OKT4, OKT8, OKM1 and anti-Ia hybridoma antibodies (Abs). T cells were prepared by sheep erythrocyte (E) rosetting after removal of adherent cells. T cells, or non-T cells, were preincubated with SLE sera at 4 degrees C and then with monoclonal Abs. Binding by specific monoclonal Abs was assessed by two methods: rosetting with ox erythrocytes conjugated with goat anti-mouse IgG and also in the fluorescence-activated cell sorter using fluorescein isothiocyanate-conjugated goat anti-mouse IgG. Using the rosetting method, we found that sera from SLE can block the binding of monoclonal mouse hybridoma anti-Ia Abs to T cells; the blocking of other monoclonal Abs was not consistent. Using fluorescence-activated cell sorter analysis, preincubation with SLE sera lowered the intensity of staining and total percentage of either T or non-T cells stained by monoclonal anti-Ia Abs. Blocking of anti-Ia Abs binding by SLE sera was not histocompatibility leukocyte antigen (HLA)-DR restricted and was not due to Fc receptor binding. These results indicated that antibodies in SLE sera react with structures contiguous to or identical with Ia determinants. Anti-Ia activities in SLE sera correlate with SLE disease activity. In addition, there was a significant negative correlation between anti-Ia blocking activity in the sera and the percentage of Ia-positive T cells in the blood of SLE patients. Antibodies in SLE sera with anti-Ia blocking activity may play an important role in immune dysregulation in SLE patients.

Antibody Specificity↗
PubMed1982

T lymphocyte interaction with immunoglobulin G antibody in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease with multiple immune disturbances whose mechanisms remain unclear. We examined the interaction of antilymphocyte antibodies with cultured normal T lymphocytes. T cells were prepared by E-rosetting after petri-dish removal of adherent cells and cultured for 2-7 d in the presence of SLE sera or normal human sera. Cultured T cells were washed and sonicated, and the amount of cell-associated IgG was quantitated by radioimmunoassay or enzyme-linked immunoassay (ELISA) methods. T cells cultured with 27 of 39 SLE sera showed marked increments of associated immunoglobulin G (IgG) although this was not observed with sera from mixed connective tissue disease patients containing high titers of ribonucleoprotein antibody or normal donors. The effective factors for IgG association in SLE sera were absorbed with normal peripheral blood lymphocytes or T cells. Anti-T cell IgG cytotoxic activity strongly correlated with T cell IgG association (P less than 0.01). T cell-associated IgG was not removed by stripping of cell membrane IgG from living cells by acid buffer treatment; indirect immunofluorescence of cells fixed after 2-4 d of culture revealed cytoplasmic IgG staining. IgG anti-T cell antibodies appeared to associate inside the cell membrane or to penetrate into the cytoplasm of cells. T cell Fc receptor blocking by heat-aggregated IgG or anti-beta 2-microglobulin antibody did not alter IgG cell association. Since pepsin-digested SLE sera showed no T cell association activity, whole IgG antibody molecules appeared to be necessary for interaction with cultured T cells. In addition, reduction and alkylation of active SLE sera completely nullified T cell reactivity. When normal T cells were cultured with SLE sera showing marked IgG T cell association, viability of cultured T cells decreased rapidly after 4 d, which suggests that IgG anti-T cell antibodies were associated with cell destruction. IgG cell-associating antilymphocyte antibodies present in SLE sera may cause T cell disturbances in vivo and may be related to the lymphocytopenia present in SLE patients.

Adult↗
PubMed1982

Immunohistochemical characterization of hepatic tissue lymphocyte subpopulations in liver disease.

Liver biopsies from 27 patients were studied by the indirect immunofluorescence and immunoperoxidase technique for relative distribution of B cells and T-cell subpopulations. T-cell subsets were defined for OKT4(+) (helper/inducer) and OKT8(+) (suppressor/cytotoxic) cells by using mouse hybridoma monoclonal antibodies. Patients with chronic active hepatitis and those with primary biliary cirrhosis showed marked relative increments in suppressor/cytotoxic OKT8(+) lymphocytes within hepatic lymphocytic infiltrates. Other patients with acute hepatitis or those with only reactive changes also showed a relative increment in OKT8(+) T lymphocytes within hepatic biopsy material. These findings suggest that tissue lymphocytic subpopulation increments in suppressor/cytotoxic T-cell subpopulations are commonly associated with hepatic lymphocytic infiltrates and may be related to disorders of immune regulation or expression in some of these disorders.

Adolescent↗
PubMed1982

A human lymphocyte chemotactic factor produced by the mixed lymphocyte reaction.

Lymphocytes migrate to and concentrate at sites of antigenic challenge. Although these cells are seen in delayed cutaneous hypersensitivity reactions and graft rejections, the mechanism by which they are attracted to these sites is poorly understood. In the current study, human mononuclear cells from normal subjects were cultured for 7 days in a standard two-way MLR. Supernatants from the MLR were assayed at various times for the presence of lymphocyte chemotactic activity. Results indicate that a lymphocyte chemotactic factor is produced by the MLR, with maximal activity appearing after 24 to 48 hr of culture. This activity is diminished with longer incubation times. The observed factor is heat labile after a 56 degrees C, 30 min heat treatment and preferentially attracts T lymphocytes. Additional studies demonstrate that MLR supernatants stimulate both directional locomotion (chemotaxis) and enhanced random locomotion (chemokinesis) in T cells. The release of such a human T lymphocyte chemotactic factor during the MLR may represent an important mechanism of attracting lymphocytes to a site of antigenic challenge.

Cell Movement↗
PubMed1982

Multivariate analysis of HLA-disease associations.

A multivariate procedure is presented for the analysis of HLA-disease associations. This formulation explicitly accounts for the inner correlations of the HLA complex itself, both within loci (arising from the fact that multinomial allelic frequencies must sum to unity) and between loci (arising from a failure of independent assortment). The analysis yields a single test criterion for association of the HLA complex, as a whole, with the disease in question: this criterion has an approximately chi square distribution. The overall test may conveniently be partitioned into a variety of interesting and independent subtests, so a decomposition of the problem is possible. The analysis is illustrated with data derived from a study of guttate psoriasis by Williams et al. (1976, British Journal of Dermatology 95, 163-167). Extensions to related problems are indicated.

Alleles↗
PubMed1981

Cyanobacterial phycobilisomes. Phycocyanin assembly in the rod substructures of anabaena variabilis phycobilisomes.

Phycocyanin complexes with "linker" polypeptides (Lundell, D. J., Williams, R. C., and Glazer, A. N. (1981) J. Biol. Chem. 256, 3580-3592) of 27 and 32.5 kilodaltons have been isolated from dissociated Anabaena variabilis phycobilisomes. In 0.05 M phosphate at pH 7.0, these "trimeric" complexes have the molar composition (alpha beta)3 . 27,000 and (alpha beta)3 . 32,500, where alpha and beta are the subunits of phycocyanin and 27,000 and 32,500 denote single copies of the linker polypeptides. The (alpha beta)3 . 27,000 and (alpha beta)3 . 32,500 complexes have lambda max at 638 and 629 nm and fluorescence emission maxima at 651 and 646 nm, respectively. In 0.6 M phosphate at pH 8.0, the (alpha beta)3 . 27,000 complex forms an (alpha beta)6 . 27,000 disc-shaped aggregate as seen in the electron microscope, whereas the (alpha beta)3 . 32,500 complex forms discs, (alpha beta)6 . 32,500, and stacked disc rods of varying lengths. The former material, containing the 27,000 polypeptide, when mixed with the (alpha beta)6 . 32,500 discs, limits their assembly into rods. The spectroscopic properties of the discs and rods assembled in vitro indicate that energy transfer in phycobilisome rod substructures proceeds from (alpha beta)6 . 32,500 discs to the (alpha beta)6 . 27,000 disc proximal to the core and thence to the core.

Circular Dichroism↗
PubMed1981

Changes in the circular dichroic spectrum of colchicine associated with its binding to tubulin.

Circular dichroism has been used to study the interaction of colchicine with the tubulin alpha beta dimer at 26 degrees C. Tubulin purified from bovine brain microtubule protein exhibits negligible circular dichroism at wavelengths above 310 nm. Free colchicine exhibits a negative circular dichroic band at 340 nm characterized by an extremum in molar ellipticity [theta] of -3.35 (+/- 0.27) x 10(4) deg.cm2/dmol. This negative band either vanished or was greatly reduced, i.e., [theta] = 0 (+/- 0.57) x 10(4) deg.cm2/dmol, when colchicine was bound to tubulin. This was demonstrated by circular dichroic studies on stable [3H]colchicine-tubulin complexes which were separated from all unbound colchicine by means of gel filtration. Also, tubulin was titrated with colchicine, and at low colchicine concentrations, the observed ellipticity at 340 nm could be extrapolated to zero at 0 M colchicine; saturation occurred at a molar ratio of colchicine to tubulin of about 1:1. The association constant characterizing the drug-protein interaction was estimated to be about 0.9 micro M-1. As controls, three other acidic proteins were studied at a molar ratio of colchicine to protein of 2:1, and their presence had no effect on the circular dichroic properties of colchicine. These results are consistent with the idea that a conformational change in colchicine accompanies its binding to tubulin. The spectrum of the complex between 250 and 300 nm was quite similar to that expected from simple additivity of the spectra of drug and protein except between 255 and 265 nm. The technique described herein should be applicable to other protein-drug systems.

Animals↗