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Biomedical subjects

R C Williams

Publications and source records attributed to R C Williams.

At least 307 records · Page 17Linked to original sources
PubMed1983

Abrogation of in vitro suppressor cell activity in adult common variable hypogammaglobulinemia after TP5 treatment.

TP5, a pentapeptide containing the active site of thymopoietin, was administered to five adult patients with CVH subcutaneously three times weekly for periods of 3 to 5 months. No significant consistent changes in lymphocyte cell surface markers or serum immunoglobulin levels were recorded; however, three of the five patients showed apparent partial reversal of in vitro suppressor T cell activity. In two of these three patients, initial skin test anergy showed temporary reversal during TP5 treatment. Two patients also showed an increase in ability of their B cells to synthesize lg in vitro when co-cultured with autologous or isologous T cells from normal donors. These changes did not persist after withdrawal of TP5 treatment.

Adult↗
PubMed1983

alpha-Interferon increases immunoglobulin production in cultured human mononuclear leukocytes.

Interferons (IFN) are known to modulate immune responses in either an inhibitory or a stimulating manner. The present study was initiated to investigate the mechanisms by which alpha-IFN modulates Ig production of human peripheral blood mononuclear cells (PBMC). IgG and IgM production was measured in pokeweed mitogen- (PWM) stimulated 7-day cultures of PBMC. Significant enhancement of IgM and IgG production was observed when alpha-IFN was added. Overnight preincubation followed by washing also produced significant enhancement. The effect of alpha-IFN was not obtained in the absence of PWM or T cells. The effect of alpha-IFN on cultures of B and T cells was not altered by irradiation of T cells (2000 rad). alpha-IFN was not shown to enhance the production of helper factor but did increase the responsiveness of B cells to helper factor if the B cells were preincubated with alpha-IFN. Finally, alpha-IFN did not increase the Ig production of PBMC induced by Epstein Barr virus (EBV), and the outgrowth of EBV-infected PBMC was not affected. Overall, these results show for the first time that the effect of alpha-IFN on PBMC is due to an enhanced responsiveness of B cells to helper factors produced by radioresistant T cells.

Adult↗
PubMed1983

Characterization of immune complexes in acute lymphoblastic leukaemia.

Sera from 120 children and young adults with acute leukaemia (59), various other tumours (53) and histiocytosis X (eight) were studied for the presence and characteristics of circulating immune complexes (CIC). Serial and parallel testing was performed using: C1q binding (solid phase), Raji cell radioimmunoassay and anti-C3 (solid phase). CIC were detected in 36 of 56 (64%) patients with acute lymphoblastic leukaemia (ALL) and in 62% of other tumour subjects. In the ALL sera, the mean positive C1q binding was 5.4 s.d., Raji cell 4.2 s.d. and anti-C3 4.4 s.d. In 12 ALL sera CIC were characterized for molecular size by sucrose gradient centrifugation. Most samples showed high molecular weight (19S) complexes but intermediate (11-14S) and smaller (8-9S) complexes were also detected. There was no apparent relationship between the presence, amount or physical size of the detectable CICs and clinical course of the patients studied; 12 patients with ALL in long term remission showed presence of CIC at some time during their course. Immune complexes precipitated from leukaemic sera were also examined for the presence of common ALL antigen (cALL) and Ia(DR) antigens utilizing rabbit antisera and mouse monoclonal antibodies. Experiments with isolated immune complexes from ALL sera provided no positive evidence for the presence of cALL antigen or Ia antigen within immune complex materials from ALL patients.

Adolescent↗
PubMed1983

Comparative studies of mitral valves in rheumatic heart disease.

Mitral valve tissues from 195 patients with rheumatic heart disease removed at the time of cardiac surgery were studied by conventional histologic techniques. One hundred seven patients from a five-year period at All-India Institute for Medical Sciences in New Delhi were studied in conjunction with 88 patients undergoing cardiac surgery in Albuquerque during a similar period. In Indian patients a correlation was noted between degree of moderate or severe valvular calcification and extent of adjacent valvular mononuclear cellular infiltration often consisting of striking lymphocytic-plasma cell collections. Similar distinct correlations were not observed among the mitral valves from the Albuquerque patients. It is possible that mitral valve mononuclear cell infiltrates among Indian patients may reflect a chronic immune reaction influencing the natural course of rheumatic heart disease in this latter population.

Adolescent↗
PubMed1983

Agglutination and phagocytosis of pneumococci by immunoglobulin G antibodies of restricted heterogeneity.

Sera from rabbits that were hyperimmune to type 3 or type 8 pneumococcal capsular polysaccharide were fractionated by starch block electrophoresis, and fractions containing large quantities of anticapsular IgG of restricted molecular heterogeneity were evaluated for their ability to agglutinate and opsonize encapsulated pneumococci. Specific anticapsular IgG was readily absorbed by the organisms. Each CFU of type 3 organisms was capable of absorbing 5 X 10(7) molecules of IgG, and the type 8 organisms absorbed 5 X 10(6) molecules/CFU. Only small amounts of nonimmune IgG were absorbed. Agglutination occurred only after 10(6) molecules/CFU IgG had been absorbed by type 3 organisms, and 10(4) to 10(5) molecules/CFU had been absorbed by type 8 organisms. After larger quantities of IgG had been absorbed, a prozone phenomenon was apparent. Anticapsular IgG in the absence of complement did not promote phagocytosis by human or rabbit PMNs below levels that caused agglutination. In the presence of complement, only about one tenth as much IgG was necessary to promote phagocytosis. Thus these encapsulated pneumococci can absorb large quantities of specific rabbit IgG antibody of restricted heterogeneity. In the presence of complement, approximately 1% of the antibody that can be absorbed by the organisms will promote phagocytosis. In the absence of complement, approximately 10% of the antibody that can be absorbed is required for agglutination or phagocytosis.

Agglutination Tests↗
PubMed1983

The 'Alice in Wonderland' experience. Ergot alkaloid therapy for prolactin-secreting pituitary tumors.

This discussion was selected from the weekly Grand Rounds in the Department of Medicine, University of New Mexico School of Medicine and Veterans Administration Medical Center, Albuquerque. Taken from a transcription, it has been edited by Drs Charles Sherman, Resident in Medicine, and Maire T. Buckman, Associate Professor of Medicine and Chief, Endocrinology Section, Veterans Administration Medical Center, Alburquerque.

Adult↗
PubMed1982

Phosphate content of mammalian neurofilaments.

The phosphate content of neurofilaments from bovine spinal cord and of their constituent polypeptides was determined. Neurofilament preparations, as isolated, contained substantial amounts of phosphate, having between 65 and 98 nmol of phosphate/mg of protein. When the polypeptides of the neurofilament were assayed for phosphate individually, the 210,000-and 160,000-dalton polypeptides were found to possess large numbers of phosphate groups, while the 68,000-dalton polypeptide had less than 1 mol of phosphate/mol of polypeptide. The 210,000-dalton polypeptide had about 104 mol of phosphate bound/mol of polypeptide, and the 160,000-dalton polypeptide had about 26 mol of phosphate/mol of polypeptide. This distribution of phosphate among the polypeptides of the neurofilament preparation was qualitatively confirmed when sodium dodecyl sulfate-polyacrylamide gels of the preparations were stained for phosphate. Bands corresponding to the 210,000- and 160,000-dalton polypeptides were readily detected. No other phosphate-stained bands were seen, even on heavily loaded gels.

Animals↗
PubMed1982

Anti-Ia antibody in the sera of normal subjects after in vivo antigenic stimulation.

We showed that sera from normal subjects after antigenic challenge with intradermal PPD or Candida antigens or with subcutaneous tetanus vaccine contain a factor that blocks the binding of mouse monoclonal anti-Ia antibody to Ia-positive T cells or to B35 M cells, an Ia-positive human B cell line. The blocking activity appears 48 to 72 h after antigenic challenge and is gone by day 7. The appearance of the anti-Ia blocking activity coincided with a drop in the percentage of Ia-positive T cells and non-T cells in the peripheral blood of these subjects and also with a decrease in the density of surface Ia on the non-T cell population. The blocking was not genetically restricted; that is, serum from a given subject blocked anti-Ia binding to Ia-positive T cells of subjects with different DR haplotypes. The blocking activity was contained in the IgM fraction of the sera. The blocking activity of the sera was eliminated after absorption of the sera with Ia-positive but not with Ia-negative human cell lines. It would appear, therefore, that the blocking of monoclonal anti-Ia binding is caused by an IgM anti-Ia antibody that appears in normals after in vivo antigenic challenge.

Antibodies, Monoclonal↗
PubMed1982

Effect of colchicine binding on the reversible dissociation of the tubulin dimer.

The reversible subunit-dissociation equilibria of the tubulin alpha beta dimer and of the colchicine-tubulin dimer complex have been examined by equilibrium ultracentrifugation at 4.6 degrees C. The dissociation constants (KD) of tubulin from bovine brain and from flagellar outer-doublet microtubules of the sea urchin Strongylocentrotus purpuratus were 7.4 x 10(-7) M and 15.2 x 10(-7) M, respectively. In contrast, both brain and outer-doublet colchicine-tubulin complexes dissociated less readily into their alpha- and beta-tubulin monomers; KD = 2.7 x 10(-7) M for the brain complex and KD = 5.0 x 10(-7) M for the outer-doublet colchicine-tubulin species. Podophyllotoxin (2 x 10(-4) M), tropolone (10(-4) M), or both podophyllotoxin and tropolone (2 x 10(-4) and 5 x 10(-4) M, respectively) had no effect on the dissociation constant of brain tubulin. Under these experimental conditions, the initial colchicine-binding capacities of brain and flagellar tubulins were 0.87 +/- 0.05 and 0.70 +/- 0.07 mol/mol, respectively. The colchicine-binding activities of free tubulins decayed at 4 degrees C according to first-order kinetics with half-times of 37 h for brain tubulin and 26 h for flagellar tubulin. However, colchicine-tubulin complexes (brain or flagellar) showed no decay of binding activity when stored at 4 degrees C for periods up to 4 days. These results strongly support the following conclusions: (1) colchicine binding induces or stabilizes a conformational isomer of tubulin that dissociates into its alpha and beta monomers less readily than free tubulin; (2) the conformational change in tubulin is specific for binding of the intact colchicine molecule and does not occur when ligands specific for the trimethoxyphenyl subdomain (i.e., podophyllotoxin) or tropolone subdomain of the colchicine-binding site bind singly or simultaneously to tubulin; and (3) bound colchicine stabilizes tubulin against loss of colchicine-binding activity at 4 degrees C. This altered conformation of tubulin may be involved in the substoichiometric poisoning of microtubule assembly produced by the addition of colchicine-tubulin complexes to the ends of microtubules.

Animals↗
PubMed1982

Changes in T-lymphocyte subsets during acute rheumatic fever.

Relative proportions and numbers of helper [OKT4(+)] and suppressor [OKT8(+)] peripheral blood lymphocytes were examined in 32 young patients during the acute phase of rheumatic fever. No significant decrease in percentage T cells during acute rheumatic fever was noted in comparison to normal children controls from the same population. A decrease in absolute numbers of OKT4(+) T cells was also noted in acute rheumatic subjects not receiving corticosteroids (P less than 0.05). In addition, a significant decrease was documented in both proportions and total numbers of OKT8(+) putative suppressor cells during acute rheumatic attacks. C-reactive protein binding to T-lymphocyte subsets showed no preferential reactivity in vivo for suppressor or helper T cells. Antigen-reactive T lymphocytes identified with the T29 mouse hybridoma reagent showed similar proportions and numbers in rheumatic children as were noted in controls. The present data indicate profound alterations in both helper- and suppressor-cell types in the peripheral blood profile of children with acute rheumatic fever.

Acute Disease↗
PubMed1982

Site-specific DNA condensation and pairing mediated by the int protein of bacteriophage lambda.

The int protein of bacteriophage lambda catalyzes the site-specific integrative recombination that inserts lambda DNA into the host chromosome. The attachment site region of lambda DNA required for this reaction spans 230 base pairs and includes four separable binding sites for int protein. We have used the electron microscope to determine the functional consequences of the interaction of int with its multiple binding sites. We find that int condenses a 230-base pair segment of DNA into a compact structure about 14 nm in diameter; the condensed region includes all of the four binding sites for int. Condensed segments will form paired structures between attachments sites. We suggest that a sequential cooperative interaction between bound int molecules provides for a distinct reactive DNA conformation and for pairing between substrate sites.

Bacteriophage lambda↗
PubMed1982

Rod substructure in cyanobacterial phycobilisomes: phycoerythrin assembly in synechocystis 6701 phycobilisomes.

Synechocystis 6701 phycobilisomes consist of a core of three cylindrical elements in an equilateral array from which extend in a fanlike manner six rods, each made up of three to four stacked disks. Previous studies (see Gingrich, J. C., L. K. Blaha, and A. N. Glazer, 1982. J. Cell Biol. 92:261-268) have shown that the rods consist of four disk-shaped complexes of biliproteins with "linker" polypeptides of 27-, 33.5-, 31.5-, and 30.5-kdaltons, listed in order starting with the disk proximal to the core: phycocyanin (alpha beta)6-27 kdalton, phycocyanin (alpha beta)6-33.5 kdalton, phycoerythrin (alpha beta)6-31.5 kdalton, phycoerythrin (alpha beta)6-30.5 kdalton, where alpha beta is the monomer of the biliprotein. Phycoerythrin complexes of the 31.5- and 30.5-kdalton polypeptides were isolated in low salt. In 0.05 M K-phosphate-1 mM EDTA at pH 7.0, these complexes had the average composition (alpha beta)2-31.5 and (alpha beta)-30.5 kdalton polypeptide, respectively. Peptide mapping of purified 31.5- and 30.5-kdalton polypeptides showed that they differed significantly in primary structure. In 0.65 M Na-K-phosphate at pH 8, these phycoerythrin complexes formed rods of stacked disks of composition (alpha beta)6-31.5 or (alpha beta)6-30.5 kdaltons. For the (alpha beta)-30.5 kdalton complex, the yield of rod assemblies was variable and the self-association of free phycoerythrin to smaller aggregates was an important competing reaction. Complementation experiments were performed with incomplete phycobilisomes from Synechocystis 6701 mutant strain CM25. These phycobilisomes are totally lacking in phycoerythrin and the 31.5- and 30.5-kdalton polypeptides, but have no other apparent structural defects. In high phosphate at pH 8, the phycoerythrin-31.5-kdalton complex formed disk assemblies at the end of the rod substructures of CM25 phycobilisomes whereas no interaction with the phycoerythrin-30.5 kdalton complex was detected. In mixtures of both the phycoerythrin-31.5 and -30.5 kdalton complexes with CM25 phycobilisomes, both complexes were incorporated at the distal ends of the rod substructures. The efficiency of energy transfer from the added phycoerythrin in complemented phycobilisomes was approximately 96%. The results show that the ordered assembly of phycoerythrin complexes seen in phycobilisomes is reproduced in the in vitro assembly process.

Cyanobacteria↗