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Biomedical subjects

B D Williams

Publications and source records attributed to B D Williams.

At least 91 records · Page 5Linked to original sources
PubMed1991

Single cell imaging reveals abnormal intracellular calcium signals within rheumatoid synovial neutrophils.

Intracellular calcium (Ca2+) signalling in synovial fluid (SF) polymorphonuclear leucocytes (PMN) from patients with rheumatoid arthritis (RA) was compared to RA and normal circulating blood PMN using single cell imaging. RA SF PMN stimulated by the peptide f-Met-Leu-Phe (FMLP) showed a striking difference in the release of Ca2+ from the intracellular store compared to RA and normal circulating blood PMN. Stimulation caused the release of a very dispersed, nonrestricted 'cloud' of Ca2+ in 60% of RA SF PMN compared to the highly localized and restricted 'cloud' observed in only 30% of normal circulating PMN. In the presence of extracellular Ca2+, both RA SF and normal blood PMN showed heterogeneity in both the timing and magnitude of their cytosolic free Ca2+ signalling. These observations imply that the Ca2+ signalling mechanism in RA SF and RA blood PMN has been primed in a way which could exacerbate the release of inflammatory mediators. This may have serious implications for explaining the aberrant behaviour of SF PMN in RA.

Adult↗
PubMed1991

Transient epidermal necrosis associated with disseminated intravascular coagulation in a patient with urticaria.

A patient with intermittent erythema developed urticaria and a systemic illness associated with the development of disseminated intravascular coagulation and a widespread bullous eruption. A skin biopsy showed intravascular fibrin and epidermal necrosis with no evidence of vasculitis. The patient made a complete recovery following therapy with fresh frozen plasma and platelets and pulsed intravenous methylprednisolone.

Adult↗
PubMed1991

Terminal complement complexes and C1/C1 inhibitor complexes in rheumatoid arthritis and other arthritic conditions.

Terminal complement complex (TCC) and C1r-C1s-C1 inhibitor complex (C1/C1 INH) concentrations were measured in plasma and synovial fluid from patients with arthritis and related to other measures of disease activity. Both TCC and C1/C1 INH concentrations were significantly increased in patients with rheumatoid arthritis (RA) compared with patients with osteoarthritis (plasma and synovial fluid, P less than 0.05) and normal subjects (plasma only, P less than 0.001). In the patients with RA, there was no correlation between plasma or synovial fluid TCC concentrations and IgM rheumatoid factor, immune complex or C1/C1 INH levels. However, in 10 patients with seronegative RA, C1/C1 INH and immune complex levels correlated significantly in synovial fluid (r = 0.69, P less than 0.05) although not in plasma (r = 0.52). Plasma and synovial fluid TCC and C1/C1 INH concentrations did not differ in rheumatoid patients with severe compared with mild joint disease (categorized by the Ritchie score). These results confirm a role for complement activation in RA but suggest that several mechanisms are involved in its pathogenesis.

Adult↗
PubMed1990

Complement-mediated inhibition of immune precipitation in rheumatoid vasculitis.

Complement-mediated inhibition of immune precipitation (CMIP) was measured in patients with rheumatoid arthritis (RA), rheumatoid vasculitis (RA VASC), patients with skin vasculitis not associated with a systemic connective tissue disease and normal healthy controls. CMIP was impaired in 100% (14/14) of the RA vasculitic patients, 60% (12/20) of the RA patients and 22% (2/9) of the dermovasculitic patients. The degree of impairment of CMIP was significantly greater in the RA vasculitic patients compared to the non-vasculitic patients. This difference was due to the significantly lower complement levels and the presence of higher concentrations of an inhibitor of CMIP in the RA vasculitic sera. The levels of this inhibitory activity correlated significantly with IgM rheumatoid factor concentration. Serial studies in three patients with RA vasculitis treated with corticosteroids and immunosuppressive drugs showed significant clinical improvement in two patients, which was associated with improvement in CMIP, reduction in circulating immune complex levels and reduction in IgM rheumatoid factor concentrations.

Adrenal Cortex Hormones↗
PubMed1990

Rescue of a paralyzed-flagella mutant of Chlamydomonas by transformation.

The biflagellate alga Chlamydomonas has been used extensively in the genetic and biochemical analysis of flagellar assembly and motility. We have restored motility to a paralyzed-flagella mutant of Chlamydomonas by transforming with the corresponding wild-type gene. A nitrate reductase-deficient paralyzed-flagella strain, nit1-305 pf-14, carrying mutations in the genes for nitrate reductase and radial spoke protein 3, was transformed with wild-type copies of both genes. Two-thirds of the cells that survived nitrate selection also regained motility, indicating that they had been transformed with both the nitrate reductase and radial spoke protein 3 genes. Transformants typically contained multiple copies of both genes, genetically linked to each other, but not linked to the original mutant loci. Complementation of paralyzed-flagella mutants by transformation is a powerful tool for investigating flagellar assembly and function.

Blotting, Southern↗
PubMed1990

Synovial fluid polymorphonuclear leucocytes from patients with rheumatoid arthritis have reduced MPO and NADPH-oxidase activity.

Synovial fluid (SF) polymorphonuclear leucocytes (PMN) from patients with rheumatoid arthritis (RA) were compared to RA and normal circulating blood PMN. RA SF PMN were as viable as blood PMN and remained viable for up to 24 h in culture. Measurement of myeloperoxidase indicated that RA SF PMN had degranulated and secreted their myeloperoxidase prior to isolation, 26.5 +/- 11.7% being found extracellularly compared to less than 2.9% in RA and normal blood PMN. RA SF PMN alone showed a decrease in basal NADPH-oxidase activity as well as an increase in responsiveness to stimulation by chemotactic peptide during culture. Stimulation of PMN with phorbol-12-myrisitate-13-acetate evoked equivalent responses in each population before and after culture. These results demonstrate a major difference in resting and receptor-mediated activation of superoxide release by RA SF PMN. Together, these results have important implications in identifying the role of the activated PMN in RA.

Arthritis, Rheumatoid↗
PubMed1990

Systemic lupus erythematosus presenting as pneumococcal septicaemia and septic arthritis.

A 50 year old woman presented with pneumococcal septicaemia, septic arthritis, and a lobar pneumonia and was subsequently diagnosed as having systemic lupus erythematosus. The blood film and splenic 99mTc sulphur colloid uptake were normal, although selective functional hyposplenism was shown by the impaired clearance of immunoglobulin coated erythrocytes. Systemic lupus erythematosus presenting with fulminating pneumococcal sepsis in the presence of selective defects in spleen function is previously unreported.

Arthritis, Infectious↗
PubMed1990

Specific accumulation of cholesterol-rich liposomes in the inflammatory tissue of rats with adjuvant arthritis.

High performance liquid chromatography has shown that after intravenous injection cholesterol-poor liposomes (100 nm) are unstable and their phospholipid is redistributed. Under identical conditions cholesterol-rich liposomes remain structurally intact within the circulation. When injected intravenously cholesterol-rich liposomes accumulate within the inflamed paws of rats with adjuvant induced arthritis to the same extent as cholesterol-poor liposomes. Uptake in inflamed tissue of three cholesterol-rich liposome preparations was always significantly greater than the uptake noted in normal tissue. The degree of accumulation in inflamed tissue was found to depend on the size of the liposome, with the greatest uptake, 7% of the injected dose, achieved by the smallest vesicle (100 nm). These results indicate that intact liposomes accumulate at inflamed joint tissue sites. Therefore the passive targeting of anti-inflammatory drugs encapsulated within these liposomes could be contemplated.

Animals↗
PubMed1990

Stimulation of human rheumatoid synovial cells by non-lethal complement membrane attack.

The effects of non-lethal complement attack on cultured human rheumatoid synovial cells have been investigated by measuring a variety of parameters. Within 3-4 min of initiating non-lethal complement membrane attack there was a rise in reactive oxygen metabolite release from cultured synovial cells, which slowly returned to basal levels over a period of 45 min. The response was dependent on the formation of the complete C5b-9 complex. Prostaglandin E2 was also released during non-lethal attack in a biphasic manner, an early phase of release occurring within the first hour and a second, larger phase commencing at 4 hr and rising to levels of over 1000 ng/10(6) cells at 24 hr, compared to control levels at this time of less than 100 ng/10(6) cells. This response was dependent on the formation of the C5b-8 complex but did not require C9. Removal of extracellular calcium reduced release of prostaglandin E2 to background levels, and inclusion of an inhibitor of protein synthesis abolished the second phase of release but not the first phase. Non-lethal attack caused release of small amounts of leukotriene B4 but no detectable release of tumour necrosis factor.

Cells, Cultured↗
PubMed1990

Human rheumatoid synovial cell stimulation by the membrane attack complex and other pore-forming toxins in vitro: the role of calcium in cell activation.

The effects of non-lethal amounts of a variety of pore-forming agents on cultured human rheumatoid synovial cells (HRSC) have been investigated. Non-lethal complement membrane attack and non-lethal amounts of melittin, perforin and ionomycin all caused a biphasic release of prostaglandin E2 (PGE2) from HRSC, an early phase of release occurring within 1 hr and a second larger phase commencing after 4 hr and continuing over the 24-hr time-course. Removal of extracellular calcium abolished the release of PGE2 under all conditions of non-lethal attack. Modulation of G-protein activity reduced the second phase of release caused by non-lethal doses of the membrane-attack complex (MAC) from 800 ng/10(6) cells PGE2 to around 300 ng/10(6) cells. Non-lethal levels of the MAC also caused release of interleukin-6 (IL-6) from HRSC over the 24-hr time-course, with levels reaching 550 ng/10(6) cells at 24 hr compared to background levels of 200 ng/10(6) cells. No detectable release of IL-1 alpha could be measured at any time following non-lethal complement membrane attack. These results suggest a role for the MAC as an initiating mediator inducing the inflammation associated with rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1989

Synthesis and characterization of 5-[(4-Azidophenacyl)thio]uridine 5'-triphosphate, a cleavable photo-cross-linking nucleotide analogue.

The synthesis, isolation, and characterization of a new photo-cross-linking uridine 5'-triphosphate analogue are described. This nucleotide analogue, 5-[(4-azidophenacyl)thio]uridine 5'-triphosphate (5-APAS-UTP), contains an aryl azide group approximately 10 A from the uridine ring. The azide is photoactivated by irradiation at 300 nm, resulting in covalent attachment of the nucleotide to adjacent molecules. The nucleotide can be desulfurated with Raney nickel to cause molecular cleavage between the base and the aryl azide. Desulfuration yields uridine 5'-triphosphate and p-azidoacetophenone. If the analogue is cross-linked to another molecule, desulfuration leaves the analogue's acetophenone group attached to that molecule. This effectively leaves behind a molecular tag on molecules that interact with the uridine analogue either as monomeric nucleotide or as part of an RNA molecule. This nucleotide analogue can be incorporated into internal positions in RNA by transcription in vitro with Escherichia coli RNA polymerase. It can therefore be used to examine interactions between RNA and other molecules (e.g., proteins or nucleic acids). Because the sulfur atom can be selectively removed, the covalent bonds formed between analogue-containing RNA and other molecules can be cleaved, when desired, to facilitate identification of the cross-linked molecules and RNA nucleotides in the cross-linked complex.

Azides↗
PubMed1989

Molecular cloning and sequence analysis of the Chlamydomonas gene coding for radial spoke protein 3: flagellar mutation pf-14 is an ochre allele.

Chlamydomonas reinhardtii flagellar motility mutant pf-14 fails to assemble radial spokes because of a deficiency for assembly-competent radial spoke protein 3 (Huang, B., G. Piperno, Z. Ramanis, and D. J. L. Luck. 1981. J. Cell Biol. 88:80-88). Here, we raise an antiserum to protein 3 and use it to isolate the corresponding structural gene from an expression library. Southern blot analysis indicates that the gene is single copy and has not undergone major rearrangement in mutant pf-14 cells. Northern blot analysis suggests that wild-type amounts of an apparently normal 2.3-kb transcript accumulate in mutant cells during flagellar regeneration. When this mutant RNA is hybrid selected and translated in vitro, however, it produces a slightly truncated polypeptide 3 with an altered charge. The mutant protein 3 fails to assemble into pf-14 flagella and is maintained within a cytoplasmic pool of unassembled radial spoke polypeptides, as indicated by immunoblot analysis of proteins from whole cells and isolated axonemes using antisera to several radial spoke polypeptides. Interestingly, amounts of the mutant protein are greatly diminished relative to other spoke components. Complete genomic and cDNA nucleotide sequences were determined, and the pf-14 mutation was identified. It is a C-to-T transition near the 5' end of the protein coding region, which changes codon 21 to the ochre termination signal UAA. The size and charge of the mutant protein, and its reduced levels in cells, suggest that it is produced by relatively inefficient translational initiation as codon 42. The unphosphorylated isoform of radial spoke protein 3 is identified, and the sequence similarities between intervening sequences of the radial spoke protein 3 gene and a conserved intervening sequence of the two Chlamydomonas beta-tubulin genes (Youngblom, J., J. A. Schloss, and C. D. Silflow. 1984. Mol. Cell. Biol. 4:2686-2696) are reported.

Alleles↗
PubMed1989

Tumour necrosis factor activity in joint fluids from rheumatoid arthritis patients.

Although tumour necrosis factor (TNF) was first studied as an anti-cancer agent it is now recognized as a potent mediator of inflammation and could potentially play a role in rheumatoid arthritis. In this study TNF activity has been sought in fluids from arthritic joints. TNF was assayed by a well established bioassay which depends upon cytolysis of particular tumour cell lines and which has a limit of detection of c. 25 pg/ml. Of the 92 joint fluids tested (70 rheumatoid and 22 others) only three had demonstrable TNF activity. Despite this, joint fluid cells from all 14 patients tested (12 rheumatoid and two others) had the ability to synthesize TNF on stimulation in vitro. Subsequently it was shown that joint fluids contain a macromolecule which inhibits TNF activity in cytolytic assays and which may mask low levels of TNF activity in joint fluids.

Arthritis↗
PubMed1989

Specific accumulation of technetium-99m radiolabelled, negative liposomes in the inflamed paws of rats with adjuvant induced arthritis: effect of liposome size.

Technetium-99m labelled, negatively charged liposomes accumulate in the inflamed tissue of rats with adjuvant induced arthritis. Up to 10 times more liposome accumulation was seen in inflamed paws than in paws of control rats, and this represented 5.3% of the injected liposome dose. The accumulation of liposomes in inflamed tissue was directly related to the liposome size, the maximal accumulation occurring with liposomes less than 100 nm in diameter.

Animals↗