Search PubMed⌕ Search

Biomedical subjects

R C Williams

Publications and source records attributed to R C Williams.

At least 361 records · Page 20Linked to original sources
PubMed1981

Circulating immune complexes in bacillary and amebic dysentery.

In order to study the relationship between the presence of circulating immune complexes (CIC) and the severity and duration of acute dysentery, we studied 11 adults and 45 children in Bangladesh with bacillary and amebic dysentery, using the Raji cell and solid-phase C1q (C1q-SPA) assays. CIC were found in 70% of patients with shigellosis and in all eight cases of amebic dysentery. Mild shigellosis was associated with positive samples in the first week of clinical illness, whereas severe cases, including those with the hemolytic-uremic syndrome, had negative admission assays but positive convalescent assays. Samples positive in the first two weeks of illness were more likely positive by the Raji cell assay alone whereas samples in the third and fourth weeks of illness were positive more often by the C1q-SPA assay. Only one shigellosis sample was positive by both assays. In amebiasis 11 of 13 samples were positive by the Raji assay alone. In dysenteric disease circulating immune complexes probably represents the failure of the inflamed mucosa to exclude microbial and dietary antigens, and suggests that the presence of CIC in any intestinal disease must be interpreted with caution.

Anemia, Hemolytic↗
PubMed1981

Lymphocyte cell subpopulations during acute post-streptococcal glomerulonephritis: cell surface antigens and binding of streptococcal membrane antigens and C-reactive protein.

T lymphocyte surface markers were examined in 23 patients with acute post-streptococcal glomerulonephritis (AGN) in parallel with normal controls and individuals without nephritis who showed evidence of pharyngeal or skin-sore beta-haemolytic streptococcal infection. Numbers of T gamma cells were similar in AGN and normal controls but were significantly lower (P less than 0.05) than those in skin-sore culture-positive streptococcal infection controls. Numbers of T mu cells were similar in AGN and normal controls but were lower (P less than 0.05) than those observed in streptococcal controls. Percentages of T mu cells were similar in AGN and normal controls but were lower (P less than 0.05) than those recorded in streptococcal infection control groups. Proportions of T cells were reduced during AGN (P less than 0.05). Lymphocytes capable of binding type 12 group A streptococcal membranes were increased (30.4%) in patients with AGN as compared to normal controls (4.1%). Subjects with streptococcal infection alone showed elevated but intermediate relative numbers (10.5%) of lymphocytes binding group A membranes. Increased relative numbers of both B and T lymphocytes binding group A streptococcal membranes were present in both AGN and non-nephritogenic streptococcal infection controls.

Acute Disease↗
PubMed1981

Study of circulating immune complex size in systemic lupus erythematosus.

The molecular size of circulating immune complexes in patients with systemic lupus erythematosus was determined by the C1q solid-phase assay after the sera were fractionated by sucrose-gradient ultracentrifugation. Circulating immune complexes in patients with membranous glomerulonephritis were uniformly large, sedimenting exclusively above 19S, whereas the immune complexes in patients with cerebritis were small, at or just above 7S. In lupus patients with diffuse proliferative glomerulonephritis and patients without renal involvement, immune complexes of both large and small sizes were found. Of patients without renal involvement, more circulating immune complexes were associated with active disease (n = 22, prevalence = 82%, mean level = 24 standard deviations) than with inactive disease (n = 17, prevalence = 41%, mean level = 41%, mean level = 6 . 5 standard deviations). In patients with clinical evidence for renal involvement, circulating immune complexes were detected in all of five patients with membranous glomerulonephritis, in 88% of 17 patients with diffuse proliferative glomerulonephritis and in one of four patients with mesangial nephritis. Thus, in addition to the finding of an overall positive correlation between disease activity and circulating immune complex levels, circulating immune complexes of certain general molecular size ranges appear to be associated with different clinical manifestations of systemic lupus erythematosus.

Adult↗
PubMed1980

Molecular architecture of a light-harvesting antenna. Comparison of wild type and mutant Synechococcus 6301 phycobilisomes.

Phycobilisomes of the cyanobacterium Synechococcus 6301 contain C-phycocyanin and allophycocyanin in a molar ratio of approximately 3.8:1, a minor biliprotein, allophycocyanin B, and nonpigmented polypeptides of 75, 33, 30, and 27 kilodaltons. A nitrosoguanidine-induced mutant AN112 produces altered phycobilisomes with the molar ratio of C-phycocyanin to allophycocyanin reduced to approximately 1.4:1 and without any of the 33- and 30-kilodalton polypeptides. The mutant and wild type phycobilisomes contain the same molar amount of the 75- and 27-kilodalton polypeptides relative to allophycocyanin. As seen by electron microscopy, the allophycocyanin-containing core of the mutant and of the wild type phycobilisomes appears the same. In some views of the core, each of the two core units in the mutant particles can be seen to consist of four discs approximately 3 nm thick. In wild type phycobilisomes five or six rods, made up of two to six stacked discs (11.5 X 6 nm) are attached to the core. In the mutant, no such rods are seen; rather, single disc-shaped elements, ranging from two to six in number, are found attached. Spectroscopic measurements show that the assembly form of phycocyanin in the mutant phycobilisomes differs from that in the wild type particles but reveal no difference in the organization of the core elements. These results indicate that the portions of the rod substructures of wild type phycobilisomes, beyond the disc proximal to the core, are made up of phycocyanin and the 33- and 30-kilodalton polypeptides. Emission from phycocyanin is a significant component in the fluorescence from isolated Synechococcus 6301 phycobilisomes and indicates an upper limit of 94% for the efficiency of energy transfer from phycocyanin to allophycocyanin and allophycocyanin B in these particles.

Cyanobacteria↗
PubMed1980

IgA paraprotein inhibition of human neutrophil chemotaxis. Reduced activity following treatment with IgA-specific protease from Neisseria gonorrhoeae.

Removal of the Fc region of human IgA m components by treatment with IgA-specific protease from Neisseria gonorrhoeae reduces the neutrophil chemotactic inhibitory activity associated with IgA M components. This observation, along with the failure of an IgA halfmer paraprotein to inhibit neutrophil chemotaxis, emphasizes the importance of the IgA Fc region in the inhibition of neutrophil chemotaxis by IgA M components.

Chemical Phenomena↗
PubMed1980

Studies on the modulation of immunoglobulin production by prostaglandins.

The present study investigated the effect of prostaglandins (PG) on the in vitro production of polyclonal IgG and IgM by pokeweed mitogen- stimulated normal human peripheral mononuclear cells. Concentrations of PGE1 and PGA1 in excess of 10(-6)M were suppressive. PGE2 and PGs of the F series were less effective and significant suppression was seen in concentrations greater than 10(05)M. Indomethacin added to cell cultures did not enhance Ig production. This discrepancy between physiologic PG concentrations and the very large pharmacologic concentration necessary to suppress Ig synthesis in vitro makes the physiologic role of PG in the modulation of Ig synthesis questionable.

Adolescent↗
PubMed1980

Immune complex-mediated rheumatic diseases: the evidence and the enigmas.

Clearly, many of the connective tissue disorders are intimately associated with either focal tissue evidence of immune complex deposition or markedly elevated levels of complexes during acute disease activity. In many diseases, such as systemic lupus erythematosus or rheumatoid arthritis, the immune complexes have been firmly established as basic elements in pathogenesis. In other disorders, however, the presence or measurable elevation of circulating immune complex materials may represent an epiphenomenon that reflects tissue injury secondary to the underlying inflammatory process. Much more precise definition of these problems awaits further longitudinal study.

Antibodies, Antinuclear↗
PubMed1980

Cyanobacterial phycobilisomes. Particles from Synechocystis 6701 and two pigment mutants.

The phycobilisomes of the unicellular cyanobacterium Synechocystis 6701, grown in white light, contain C-phycoerythrin, C-phycocyanin, and allophycocyanin in a molar ration of approximately 2:2:1, and in addition, polypeptides of 99, 46, 33.5, 31.5, 30.5, and 27 x 10(3) Daltons, as well as a trace of a approximately 9 x 10(3)-dalton component. Two nitrosoguanidine-induced mutants of this organism produce aberrant phycobilisomes. Crude cell extracts of these mutants, 6701-NTG25 and NTG31, contain phycoerythrin, phycocyanin, and allophycocyanin in a molar ration of 1:5:1:1 and 0.55:0.3:1.0, respectively. The phycobilisomes from both mutants lack the 33.5 x 10(3)-dalton polypeptide. Wile-type phycobilisomes consist of a core composed of an equilateral array of three cylindrical elements surrounded by six rods in a fanlike arrangement. The rods are made up of stacked disks, 11 nm in diameter and 6 nm thick. In phycobilisomes of mutant 6701-NTG25, numerous particles with fewer than six rods are seen. Mutant 6701-NTG31 produces incomplete structures that extend from triangular core particles, through cores with one or two attached rods, to cores with as many as five rods. The structure of the core appears unaltered throughout. The amount of phycocyanin (relative to allophycocyanin) appears to determine the number of rods per core. A common assembly form seen in 6701-NTG31 is the core with two rods attached at opposite sides. From observations of this form, it is concluded that the core elements are cylindrical, with a height of 14 nm and a diameter of 11 nm. No consistently recognizable structural details are evident within the core elements.

Cyanobacteria↗
PubMed1980

Streptococcal adherence to pharyngeal cells of children with acute rheumatic fever.

The adherence of strains of group A Streptococcus to pharyngeal cells from Egyptian children with acute rheumatic fever (RF) was examined. Nine RF-associated and eight unassociated streptococcal strains were tested in vitro for adherence to pharyngeal cells from 11 patients with acute RF and eight normal subjects. RF-associated streptococcal strains adhered more avidly to pharyngeal cells of patients with acute RF (mean, 11.8 bacteria/cell) than did unassociated strains (mean, 5.9 bacteria/cell; P less than 0.05). The difference in mean adherence could be attributed to certain RF-associated strains. There was no significant difference in adherence when pharyngeal cells from controls were used. Furthermore, one RF-associated streptococcal strain was found to adhere considerably more avidly to pharyngeal cells of patients with RF than to those of controls.

Adolescent↗
PubMed1980

Effect of intravenously injected killed pneumococci on leukocytes, complement, and phagocytosis in rabbits.

A pneumococcal infection may be lethal in the absence of overwhelming pulmonary involvement, and death may occur even after the organisms have been killed with antibiotics. The mechanism of death is not understood but may be related to circulating pneumococcal products. For investigating the effects of nonviable pneumococci on several host defense mechanisms, rabbits were injected intravenously with 4 X 10(8) colony-forming units of killed sonified type 13 or type 29 pneumococci. Blood was sampled periodically for the next 24 h, and the following were measured: (i) circulating levels of leukocytes; (ii) activity of the classical and alternate complement pathways; and (iii) ability of the serum to opsonize pneumococci for ingestion and killing by polymorphonuclear leukocytes. Saline-injected control rabbits showed no change in any of the functions. Nonimmune rabbits injected with either pneumococcal serotype showed progressive and profound leukopenia, no change or an increase in classical and alternate complement pathway activity, and a profound reduction in the serum-opsonizing capcity for pneumococci of the same serotype as that used in the injection. The opsonizing capacity remained normal for the other serotype. When a previously immunized animal was injected, the opsonizing capacity for the homologous organism remained intact, but leukopenia nervertheless occurred.

Animals↗