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Biomedical subjects

A M Wootton

Publications and source records attributed to A M Wootton.

13 recordsLinked to original sources
PubMed1995

Serum IL-4, IL-10 and IL-6 levels in inflammatory arthritis.

As the available in vitro and in vivo data suggest that interleukin (IL)-4 and IL-10 have immunosuppressive activity, our hypothesis was that serum IL-4 and IL-10 levels would correlate inversely with parameters of inflammation in patients with inflammatory arthritis. IL-4 was detected in the serum of 12 out of 140 patients with rheumatoid arthritis (RA), which was increased compared to the proportion found with patients with osteoarthritis (OA; P < 0.02). In addition, IL-4 was detected in the serum of 2 of 19 patients with systemic lupus erythematosus (SLE), 2 of 24 patients with psoriatic arthritis and 1 of 5 patients with Behçet's syndrome. No IL-4 was detected in patients with the following conditions: OA (58 patients), gout (17 patients), ankylosing spondylitis (6 patients), Reiter's syndrome (6 patients), polymyalgia rheumatica (6 patients), temporal arteritis (5 patients) and scleroderma (3 patients). No IL-10 was detected in any of the sera tested. We discuss the possible relevance of these results to the regulation of the immune response evident in inflammatory arthritis.

Adolescent↗
PubMed1994

Dermatophagoides pteronyssinus II-induced interleukin-4 and interferon-gamma expression by freshly isolated lymphocytes of atopic individuals.

Cytokines are known to play a major role in mediating many of the immunological and pathological features of allergic disease. Much of our understanding of cytokine production in response to allergens has come from studying allergen-specific T cell clones following long-term in vitro culture. This has largely been due to the lack of sufficiently sensitive assays to measure allergen-induced cytokine production by freshly isolated peripheral blood mononuclear cells (PBMCs). Here we have used the polymerase chain reaction to amplify reverse transcribed interleukin-4 (IL-4) and IFN gamma mRNA expressed by allergen-stimulated PBMCs from a variety atopic individuals. Using Der p II, a major allergen of the house dust mite (HDM) Dermatophagoides pteronyssinus, we have demonstrated that cells from HDM-sensitive atopic patients (n = 12), can be induced to express either IL-4 alone (three patients), IL-4 and IFN gamma (six patients), IFN gamma alone (two patients) or neither cytokine (one patient). Cells from 13 non-atopic control individuals were also stimulated with Der p II and cytokine mRNA production was studied. None expressed IL-4, while seven of 13 transcribed IFN gamma. Our results suggest that atopic individuals have allergen-reactive T cells at various stages of differentiation, with respect to the cytokines they produce. The use of this technique will aid in the further understanding of specific cellular hypersensitivity in allergic disease.

Animals↗
PubMed1994

IL-4 production is increased in cigarette smokers.

Cigarette smoking has been associated with both increases in serum levels of total IgE and an increased risk of developing allergic-like symptoms. IL-4 and interferon-gamma (IFN-gamma) have reciprocal roles in the regulation of IgE synthesis, and as such prompted us to evaluate, in smokers, the production of these two cytokines. We demonstrate that phytohaemagglutinin (PHA)-induced IL-4 production by peripheral blood mononuclear cells (PBMC) of smokers (n = 19) is significantly higher than that of non-smokers (n = 10, P < 0.005). In addition, PBMC from heavy smokers, defined by the number of cigarettes smoked per day, produced significantly higher levels of IL-4 than those of light smokers. No difference between the groups was found for IFN-gamma production. Our data suggest an imbalance in cytokine production occurring in individuals who smoke. This imbalance, favouring IL-4 production, may be part of the mechanism responsible for the observed increases in serum IgE and allergic-like symptoms associated with cigarette smoking.

Adult↗
PubMed1992

T cell responses to the purified major allergens from the house dust mite Dermatophagoides pteronyssinus.

Proliferation assays were used to determine peripheral blood T cell responses to affinity-purified Der p I, Der p II, and Der f II allergens. Patients studied were sensitive to the house dust mite (HDM) either alone or in combination with other allergens. Control subjects were both nonatopic and atopic non-HDM sensitive. In general, only HDM-sensitive patients responded to the mite allergens. Mean stimulation indices (SI) were 10.2 +/- 2.8 (SEM) for Der p I and 10.0 +/- 2.2 for Der p II in HDM-sensitive individuals, and 2.0 +/- 0.2 and 2.8 +/- 0.6 for non-HDM sensitive control subjects (p less than 0.001). Patients sensitive to HDM and other allergens had higher responses than subjects sensitive to HDM alone, and the degree of proliferation to Der p I and Der p II was well correlated in individual patients (r = 0.71; p less than 0.001). Total IgE levels were elevated in the allergic patients, and values were highly correlated with the SI for both Der p I and Der p II (p less than 0.001). Responses to Der p II and Der f II were equivalent in 82% of individuals; however, in 18%, there was a marked discordance with strong responses to Der p II only. SIs were compared between different clinical groups of patients, and patients with asthma had significantly higher values to both Der p I and Der p II than patients with rhinitis alone (17.0 +/- 5.4 versus 5.7 +/- 1.0 for Der p I, p less than 0.05; 14.3 +/- 6.8 versus 5.0 +/- 1.0 for Der p II, p less than 0.05).

Adult↗
PubMed1992

Interferon-gamma production in atopic dermatitis: a role for prostaglandins?

Peripheral blood mononuclear cells (PBMC) from patients with atopic dermatitis (AD) have a reduced capacity to produce interferon-gamma (IFN-gamma) in vitro, in response to phytohaemagglutinin (PHA) when compared to healthy non-atopic controls. This defect appears to correlate closely with the severity of AD at the time of sampling, with less IFN-gamma being produced by cells from patients with more severe disease. Enhanced production of IFN-gamma was observed as the patients clinical symptoms improved. In addition, IFN-gamma production could be increased by either pre-culturing the cells for 3 days prior to PHA stimulation or by addition of indomethacin to the culture medium. These observations suggest that the mechanism of reduced IFN-gamma production in AD is unlikely to be due to an intrinsic cellular defect. The possibility that prostaglandins mediate the suppressed production of IFN-gamma in AD was supported by demonstrating that exogenous prostaglandin E2 (PGE2) inhibited IFN-gamma production in PHA-stimulated PBMC. PGE2 at a physiological concentration (10(-9) M) was also shown to enhance interleukin 4 induction of IgE synthesis by PBMC cultures. Our data suggest that alterations in prostaglandin metabolism play a crucial role in the pathogenesis of AD by inhibiting the production of IFN-gamma.

Cells, Cultured↗
PubMed1991

An evaluation of the Sysmex NE-8000 hematology analyzer.

The Sysmex NE-8000 is a new, fully automated hematology analyzer capable of providing a five-part white blood cell differential count and identifying abnormal specimens. This instrument was evaluated on 5,000 consecutive blood specimens and compared to the Coulter S Plus-IV analyzer and manual differential cell counts to determine the efficacy of its five-cell differential and screening capabilities. There was a high correlation between the commercial counters for the standard parameters, white blood cell count, red blood cell count, hemoglobin level, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin concentration, and platelet count (r greater than 0.95), except for the mean corpuscular hemoglobin concentration (r = 0.51), for which the NE-8000 was considered the more accurate measurement. Precision and linearity studies were excellent. The white blood cell count, red blood cell count, hemoglobin level, and platelet count were reproducible on specimens stored at 4 degrees C or room temperature for 72 hours and the differential counts were reproducible for 12 hours. The correlations between automated and manual counts for neutrophils, eosinophils, basophils, and lymphocytes were excellent: r = 0.912, 0.945, 0.332, and 0.964, respectively. The monocyte correlation improved with software modification from 0.306 to 0.801. The NE-8000 gave accurate and reproducible differential counts for neutrophils, lymphocytes, and monocytes on specimens with white blood cell counts as low as 0.6 x 10(9)/1. The ability of the instrument to 'flag' abnormal specimens was excellent. The false-positive rate on normal samples was 1.8%, and the false-negative rate on known abnormal samples was 0.3%, due only to nonrecognition of a mild left shift. The identification of specific abnormalities was less precise. The NE-8000 is a powerful hematology analyzer that can perform a five-part white blood cell differential count accurately for a wide range of WBCs and reliably indicate abnormal specimens. It is an excellent screening tool for distinguishing between normal and abnormal specimens and identifying those that require microscopy. Its reliability significantly reduces the need for manual film examination.

Blood Cell Count↗
PubMed1991

Recombinant interferon-gamma inhibits the expression of IL-4 receptors on human lymphocytes.

Interferon gamma (IFN-gamma) has been shown to inhibit many of the activities of IL-4, including the induction of IgE synthesis and the proliferation of T cell clones. Here we demonstrate that IFN-gamma is able to inhibit the expression of IL-4 receptors on peripheral blood lymphocytes from both normal healthy donors and from patients with chronic lymphocytic leukaemia. Inhibition was shown to be dose-dependent and did not affect the binding affinity of the receptor as shown by Scatchard analysis. IFN-gamma was unable to displace labelled IL-4 from its membrane receptor, which demonstrates that IFN-gamma and IL-4 do not compete for the same membrane binding protein. The ability of IFN-gamma to down-regulate IL-4 receptors may be important in controlling certain immune responses.

Cells, Cultured↗
PubMed1990

Laboratory instrument evaluation using a personal computer.

A system in which data from multichannel biochemical analysers is downloaded to a personal computer using a communications package is described. BASIC programs were developed to format the data into a file structure suitable for importing into a commercial statistics software package. This allowed statistical comparisons to be made of patient data obtained from different instruments and facilitated evaluation of these instruments. Using this technique, many hundreds of patient results may be compared without requiring the data to be keyed into a computer. The techniques and programs used are described to show that these facilities can be developed by laboratory scientists with only rudimentary computer programming skills.

Autoanalysis↗
PubMed1980

Immunologic studies in IgA nephropathy.

Circulating immune complexes (CIC) were detected in 43.6% of 78 patients with primary IgA nephropathy by the solid-phase Clq radioimmunoassay. The IC were intermediate (9 to 17S) in size and contained IgA, IgG, and less commonly IgM. CIC were often present intermittently, correlating with episodes of macroscopic hematuria. Elevated serum IgA concentrations (38.7%) did not correlate with the detection of CIC. Similar findings were observed in sera samples from patients with Henoch Schonlein purpura and in IgA glomerulonephritis associated with alcoholic cirrhosis and/or portal systemic shunts. The factors responsible for the mesangial localization of the IC are not clear, but elevations in serum antibody titers to respiratory pathogens (mycoplasma pneumoniae, herpes virus, influenza), gut flora (E. coli 07), and bovine serum albumin suggest that common exogenous antigens may be involved in the pathogenesis. Primary defects in either mucosal antigen exclusion or reticuloendothelial IC sequestration are proposed to account for these findings.

Antigen-Antibody Complex↗
PubMed1980

Controlled trial of phenytoin therapy in IgA nephropathy.

IgA nephropathy, a condition thought to cause slowly progressive renal damage, is frequently associated with high serum IgA levels. As phenytoin sodium lowers serum IgA concentrations, a controlled trial of therapy with this drug was conducted over a two-year period in patients with IgA nephropathy. Despite significant depression of serum IgA concentrations in the treatment group, there was no significant change in any other clinical, biochemical or pathological parameter, in either control or treatment groups. Indeed, there was evidence for a slow progression of renal damage in both groups. These observations suggest that the elevated serum IgA concentrations in IgA nephropathy are not of primary pahtogenetic significance but are rather a consequence of a basic abnormality in antigen processing and IgA production.

Adolescent↗
PubMed1978

Analytical subcellular fractionation studies on different cell types isolated from normal rat liver.

1. Parenchymal, Kupffer and biliary tract cells were isolated from normal rat liver by perfusion with collagenase solution. 2. The specific activities (munits of enzyme activity/mg of protein) of marker enzymes for the principal subcellular organelles were determined in the isolated cell homogenates and compared with whole liver homogenates. 3. The cells were disrupted and the extracts subjected to analytical subcellular fractionation by sucrose-density-gradient centrifugation. Lysosomal integrity was determined by assaying latent beta-N-acetylglucosaminidase in the extracts. 4. Similar subcellular distributions were found for lysosomal, endoplasmic reticulum and plasma membrane marker enzymes in the whole liver and in parenchymal and biliary tract cells. In Kupffer cells, the proportion of these enzymes in the cytosol was significantly increased compared with the other fractions. In addition the equilibrium densities of the various organelles in these cells were lower than those from parenchymal cells.

Animals↗
PubMed1975

Some properties of alkaline-phosphatases in parenchymal and biliary tract cells separated from rat liver.

Livers of both normal and bile-duct ligated rats have been separated into parenchymal cells and fractions enriched in biliary tract cells. The specific activity of alkaline phosphatase increases in both types of cells after occlusion of the bile duct but the increase is more marked in the case of parenchymal cells. The enzyme from parenchymal cells migrates as a single zone on electrophoresis, whereas additional zones of lower anodal mobility occur in extracts of biliary tract preparations. The alkaline phosphatase activity of the slower zones is significantly less stable to heat than that of the zone characteristic of parenchymal cells. It is postulated that the increase in heat stability of alkaline phosphate in extracts of whole rat liver after bile-duct ligation is due to an increase in the proportion of the more stable form of the enzyme predominant in parenchymal cells.

Alkaline Phosphatase↗