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Biomedical subjects

T A McNeill

Publications and source records attributed to T A McNeill.

At least 19 recordsLinked to original sources
PubMed1995

The effects of thiopentone and propofol on delayed hypersensitivity reactions.

The effects of thiopentone and propofol on delayed hypersensitivity reactions and T lymphocyte proliferation were studied in nine healthy volunteers (five women and four men). Thiopentone 5 mg.kg-1 and propofol 2.5 mg kg-1 were given as a 10 min infusion on two separate occasions. The volunteers were exposed to a skin multitest antigen before and after administration of the two agents and their skin reactions assessed. T lymphocyte responses were studied using phytohaemagglutinin (PHA)-induced proliferation. Results showed that both drugs caused a significant depression of skin reactions in vivo but no depression in the T lymphocyte proliferation.

Adult↗
PubMed1995

Transient immunomodulation by intravenous methylprednisolone treatment of multiple sclerosis.

The extent and duration of immunomodulation induced by high-dose corticosteroid treatment of clinical relapse of multiple sclerosis was investigated. Ten patients treated with a 5 day course of intravenous methylprednisolone (IVMP) (500 mg daily) were studied. Circulating lymphocyte subpopulations and mitogen-induced interleukin 2 (IL-2) and gamma-interferon (gamma-IFN) production were determined immediately before initiation of therapy (day 1), during therapy (24 h after first dose, day 2) and at 24 h and 1 week post therapy (days 6 and 12 respectively). T-cell subpopulation (CD3, CD4, CD8, CD4CD45RA, CD4CD45RO) levels fell within 24 h of initiation of therapy, rebounded above pretreatment levels at day 6 and normalised 1 week post therapy. Despite a reduction in total T-cell numbers during treatment, the gamma delta T-cell subpopulation was not significantly altered. HLA-DR expression on B cells and monocytes declined transiently on day 2 to approximately 50% of pretherapy levels. IL-2 and gamma-IFN production were reduced during therapy but returned to baseline levels by 24 h post therapy. The effects of IVMP on lymphocyte distribution and function appear to be short-lived and, therefore, may not be responsible for the rapid improvement associated with this form of treatment.

Adjuvants, Immunologic↗
PubMed1994

Gamma delta T cell distribution in cerebrospinal fluid and peripheral blood of patients with multiple sclerosis.

The distribution of gamma delta T cells was determined in peripheral blood of 50 patients in acute relapse of clinically definite multiple sclerosis (MS), 8 patients with primary progressive MS, 26 patients with inflammatory neurological disease (IND), 33 patients with non-inflammatory neurological disease (NIND) and 31 healthy subjects. Paired cerebrospinal fluid samples were obtained from 37 patients with relapsing-remitting MS, 2 patients with primary progressive MS, 14 with IND and 18 with NIND. The monoclonal antibodies pan-alpha beta TCR, TCR delta 1, delta TCS1 and anti-delta V2(a) which identify alpha beta T cells, gamma delta T cells, V delta 1, and V delta 2 gene products respectively, were used to define the T cell receptor repertoire. gamma delta T cells expressed as a percentage of CD3+ lymphocytes were lower in MS CSF compared to NIND CSF (3.4% +/- 0.5 versus 7.3% +/- 1.4; p < 0.001). This was due to a lower MS CSF. Peripheral blood levels of gamma delta T cells were normal in each study group. CD45RA expression was increased on gamma delta T cells in CSF of each patient group when compared with the paired blood samples. These results suggest that V delta 1 + and V delta 2 + gamma delta T cells with altered CD45 expression are reduced in CSF of patients with established MS. This finding may be related to sequestration or apoptosis of gamma delta T cells within active MS lesions.

Adult↗
PubMed1994

Predictive value of soluble immunological mediators in neonatal infection.

1. Infection in the neonatal period is difficult to diagnose and is a significant cause of morbidity and mortality in preterm infants. 2. We investigated prospectively the predictive value of plasma measurement of bacterial endotoxin (lipopolysaccharide), tumour necrosis factor-alpha, interleukin-6, interleukin-8, intercellular adhesion molecule-1 and C-reactive protein in 60 consecutive newborn infants suspected of having neonatal infection. Plasma samples were taken at the time of acute clinical deterioration. Sixty-two cord blood samples were studied as controls taken at elective Caesarean section. 3. Forty-three infants had confirmed infections, 25 with positive blood cultures. Tumour necrosis factor-alpha and bacterial endotoxin levels were not significantly elevated over controls, whereas interleukin-6, interleukin-8 and intercellular adhesion molecule-1 levels were all significantly increased in the infected group compared with controls (all P < 0.001). 4. Increased plasma intercellular adhesion molecule-1 levels were a highly sensitive (88%) indicator of clinical infection and were independent of C-reactive protein. Use of these two assays in combination improved the diagnostic sensitivity to 95% and gave a negative predictive value of 97%. addition of interleukin-6 or interleukin-8 measurements failed to further significantly enhance the prediction of infection. 5. Measurement of intercellular adhesion molecule-1 level may have a clinical role in rapidly confirming, or predicting, the likely diagnosis in cases of suspected neonatal infection.

Bacterial Infections↗
PubMed1994

Effect of four i.v. induction agents on T-lymphocyte proliferations to PHA in vitro.

Anaesthetic agents are believed to have an adverse effect on human immunity. We have studied the effects of four i.v. induction agents, thiopentone, methohexitone, etomidate and propofol, on T-lymphocyte proliferations to phytohaemagglutinin in vitro. We found that at plasma concentrations similar to those obtained after induction doses, all drugs, with the exception of propofol, caused depression of T-lymphocyte function.

Anesthetics, Intravenous↗
PubMed1993

Increased expression of C1q receptors on neutrophils from inflammatory joint fluids.

C1q receptor (C1qR) expression was determined by immunofluorescence flow cytometry on neutrophils from paired peripheral blood and synovial fluid samples from 21 patients with rheumatoid arthritis (RA) and 13 patients with other articular diseases (OAD). In both patient groups the levels of C1qR on circulating neutrophils were similar to that observed for normal control subjects, whereas on synovial fluid neutrophils significantly higher levels of receptor expression were observed. The mean percentage increases observed were: RA patients 47%, OAD patients 72%. C1q-bearing immune complexes were most prevalent in patients with RA, with the highest concentrations being found in synovial fluid samples. No correlation between immune complex levels and neutrophil C1qR expression was noted. Upregulation of C1qR expression is a feature of activated neutrophils from inflammatory joint fluids.

Antigen-Antibody Complex↗
PubMed1993

An association between ANCA positive renal disease and malignancy.

The detection of anti-neutrophil cytoplasmic antibodies (ANCA) is now a routine part of the evaluation of patients clinically suspected of suffering from small vessel vasculitis. The factor(s) that trigger the development of these autoantibodies and their role in the pathogenesis of vasculitis is still unclear. We describe four patients who presented to us since June 1990. All patients had positive ANCA serology and had clinical evidence of vasculitis. In all patients soon after the establishment of ANCA positivity, a carcinoma of either the respiratory or urinary tracts was diagnosed. We suggest that in some cases of ANCA-associated vasculitis, malignant disease may be a trigger for either the generation of these autoantibodies, or the development of vasculitis.

Aged↗
PubMed1992

Markers of inflammatory activation: upregulation of complement receptors CR1 and CR3 on synovial fluid neutrophils from patients with inflammatory joint disease.

Expression of the C3 receptors CR1 and CR3 was investigated on neutrophils from paired peripheral blood and synovial fluid samples from 34 patients with inflammatory joint disease (21 patients with rheumatoid arthritis (RA) and 13 patients with other articular diseases (OAD)). Using monoclonal antibodies (anti-CD35, anti-CD11b) and immunofluorescence flow cytometric analyses the percentages of positively labeled cells and the relative fluorescence intensities (as a measure of receptor number) were determined. CR1 and CR3 were found to be present on the majority (> 85%) of circulating neutrophils from normal subjects, RA and OAD patients, and on synovial fluid neutrophils from both patient groups. A strong correlation between neutrophil CR1 and CR3 expression was observed in peripheral blood samples from normal subjects (r = 0.81; P = 0.001), RA (r = 0.79; P = 0.001), and OAD patients (r = 0.83; P = 0.001); in each case the levels of CR3 expression were approximately twice those recorded for CR1. Both CR1 and CR3 expression was upregulated on synovial fluid neutrophils compared with that observed on the corresponding peripheral blood cells. Mean percentage increases observed were: RA patients: CR1, 16.5% (P < 0.001) and CR3, 28.7% (P < 0.001); and OAD patients: CR1, 4.1% and CR3, 26.9% (P = 0.001). Correlation of serum and synovial fluid IL-6, IL-8, and immune complex levels with neutrophil CR1 and CR3 expression failed to demonstrate any significant relationship between the concentrations of these soluble factors and receptor expression. Upregulation of CR1 and CR3 receptors, reflecting neutrophil activation within the inflamed joint, is a consistent finding in patients with inflammatory arthropathies.

Adult↗
PubMed1992

CD4 lymphocyte subset abnormalities associated with impaired delayed cutaneous hypersensitivity reactions in patients with X-linked agammaglobulinaemia.

Circulating CD4 lymphocyte subset (CD45RA; CD45RO; CD29; Leu8) levels were determined in nine patients with X-linked agammaglobulinaemia (XLA), nine patients with common variable immunodeficiency (CVI) and in 18 age- and sex-matched controls. CD4CD45RO and CD4CD29 cells were significantly lower (P less than 0.01) in the XLA patient group (CD45RO, 15.7 +/- 10.2%; CD4CD29, 32.1 +/- 14.6%) compared with CVI patients (61.8 +/- 25.4%; 60.1 +/- 11.2%) and normal controls (43.7 +/- 22.3%, 54.5 +/- 22.0%). The levels of CD4CD45RA and CD4Leu8 cells were not abnormal in the XLA patient group. No selective reduction in CD4 subsets was observed in the CVI patient group. Delayed cutaneous hypersensitivity testing of five XLA and five CVI patients revealed a significantly reduced response to recall antigens in patients with XLA. This may relate to the deficiency of circulating memory T cells observed in these patients.

Adolescent↗
PubMed1991

Predictive value for coeliac disease of antibodies to gliadin, endomysium, and jejunum in patients attending for jejunal biopsy.

OBJECTIVE: To investigate the extent to which the detection of antibodies to gliadin, endomysium, and jejunum predicts the eventual diagnosis of coeliac disease according to the revised ESPGAN diagnostic criteria in a group of patients in whom there is a high suspicion of coeliac disease. DESIGN: Clinical assessment and laboratory analysis of patients with suspected coeliac disease. SETTING: Gastroenterology department of teaching hospital. PATIENTS: 96 adults with suspected coeliac disease attending for jejunal biopsy. MAIN OUTCOME MEASURES: Diagnosis of coeliac disease with the revised criteria of the European Society of Paediatric Gastroenterology and Nutrition in patients with and without antibodies associated with coeliac disease. RESULTS: 28 patients had a clinical diagnosis of coeliac disease, seven of other gastrointestinal diseases, and 12 of miscellaneous diseases; 49 had no diagnosis. Gliadin IgA detected by ELISA was found in all patients with coeliac disease and none of those without, giving a sensitivity, specificity, positive and negative predictive values, and predictive efficiency of 100% for diagnosing coeliac disease within the group. Endomysial IgA was found in 25 (89%) patients with coeliac disease and jejunal IgA in 21 (75%); neither IgA was found in patients without coeliac disease. CONCLUSION: Detection of gliadin IgA by ELISA and to a lesser extent the endomysial IgA should allow better selection of patients for jejunal biopsy and thus make diagnosing coeliac disease simpler and more efficient.

Adolescent↗
PubMed1991

Immunoglobulin isotype composition of circulating and intra-articular immune complexes in patients with inflammatory joint disease.

The immunoglobulin (Ig) heavy chain isotype composition of intra-articular and circulating immune complexes (ICs) were determined by a Raji cell flow cytometric assay in paired serum and synovial fluid samples from 15 patients with rheumatoid arthritis (RA) and 15 patients with other articular diseases (osteoarthritis, ankylosing spondylitis, gout, psoriatic arthritis, Reiter's disease). ICs were most prevalent in synovial fluid samples of patients with RA but were infrequently detected in serum and synovial fluid samples from the non-RA patients. ICs in patients with RA were heterogeneous both in the prevalence of Ig subclasses identified and in the distribution of the respective Ig isotypes within the complexes. Furthermore, differences were observed in the Ig isotype composition of ICs in paired serum and synovial fluid samples indicating that circulating ICs may not always arise simply by spill-over from articular sites. The possible mechanisms for IC formation in RA are discussed with reference to four patients who displayed features of extra-articular disease.

Adult↗
PubMed1991

Comparison of immunofluorescence and an immunohistochemical technique for the detection of perinuclear anti-neutrophil cytoplasmic antibody.

Using the standard indirect immunofluorescent (IIF) technique two types of autoantibodies are detected in the sera of patients with vasculitic disorders. These are cytoplasmic or classical antineutrophil cytoplasmic antibody (cANCA) and perinuclear anti-neutrophil cytoplasmic antibody (pANCA). In order to resolve the problems associated with the detection of pANCA an immunocytochemical technique-alkaline phosphatase anti-alkaline phosphatase (APAAP) was developed and used to detect ANCA in various groups of patients. Comparison with the standard immunofluorescence method showed that the results correlated only when immunostaining patterns were of the cANCA type. Detection of pANCA by APAAP was more uncertain than by immunofluorescence because of the greater number of staining patterns seen. Interference from antinuclear antibodies (ANA) appeared to cause more problems with the APAAP technique and sera containing ANA were not distinguished from pANCA using either immunofluorescence or APAAP. In conclusion, it appears that the APPAP technique is not a reliable method of the screening of ANCA and that pANCA has several antigenic specificities.

Autoantibodies↗
PubMed1991

Flow cytometric analysis of within-strain variation in polysaccharide expression by Bacteroides fragilis by use of murine monoclonal antibodies.

The reactivity of four different monoclonal antibodies (MAbs) with populations of Bacteroides fragilis NCTC 9343, enriched by density gradient centrifugation for a large capsule, small capsule and electron-dense layer (EDL) only visible by electronmicroscopy, was examined. The MAbs reacted strongly with polysaccharides present in both the large capsule- and EDL-enriched populations but not in the small capsule-enriched populations. The pattern of labelling was determined by immunoblotting, immunofluorescence and immuno-electronmicroscopy, and flow cytometry. The MAbs labelled cell membrane-associated epitopes in the large capsule- and EDL-enriched populations and cell-free material in the EDL population. By immunoblotting, ladders of repeating polysaccharide subunits were evident in the EDL population but not in the large capsule population. The proportion of cells labelled within each population was determined by flow cytometry. The reactivity of another MAb with the small capsule population was confirmed by flow cytometry. A qualitative indication of epitope expression was obtained by examination of the flow cytometric profiles. Differential expression of the same saccharide epitope was observed both between and within structurally distinct B. fragilis populations. The MAbs were species-specific and cross-reacted with several recent clinical isolates. These polysaccharides may be relevant to the virulence of B. fragilis.

Animals↗
PubMed1990

A T cell receptor beta chain polymorphism is associated with patients developing insulin-dependent diabetes after the age of 20 years.

We have studied the BglII polymorphism near the T cell receptor beta chain constant region (TcR-C beta) gene, HLA-DR genotypes and certain autoimmune features in 102 patients with type I (insulin-dependent) diabetes. There was a significant decrease in the frequency of the 1:1 genotype (P = 0.008) and an increase in the 1:2 genotype (P = 0.03) of the BglII TcR polymorphism in the group of patients who developed type-I diabetes after the age of 20 years. This group of patients also showed an increased incidence of autoantibodies (especially islet cell antibody), a family history of diabetes and the presence of other autoimmune diseases. The frequency of this polymorphism in patients who developed type I diabetes before the age of 20 years was similar to a non-diabetic group. These results suggest that there are two genetically distinct groups of patients with type I diabetes. HLA-DR3 and HLA-DR4 genotypes were also increased in the diabetic patients but no significant difference was observed between HLA-DR genotypes, the TcR-C beta genotypes, the age of diagnosis or with other autoimmune features. Patients developing type I (insulin-dependent) diabetes after the age of 20 years have an additional genetic susceptibility for diabetes associated with the TcR-C beta gene.

Adolescent↗
PubMed1989

Measurement of circulating immune complexes containing IgG, IgM, IgA and IgE by flow cytometry: correlation with disease activity in patients with systemic lupus erythematosus.

The immunoglobulin (Ig) class of the antibody component of circulating immune complexes (IC) may be an important determinant of their pathogenicity. This study reports the development of a fluorometric immunoassay, using Raji cells as solid phase component and detection by flow cytometry, for the measurement of IC containing IgG, IgM, IgA and IgE. Analytic specificity of the method was established and diagnostic sensitivity determined in groups of patients with various disorders. In a detailed study of 44 patients with systemic lupus erythematosus (SLE), elevated levels of IC were observed in the majority of patients, the prevalence of the respective Ig subclasses within the patient group being IgG-IC (93%); IgM-IC (77%); IgA-IC (59%); IgE-IC (52%). Raised levels of IC (of all classes) correlated with disease activity. Longitudinal study of a patient with acute cerebral SLE revealed elevated IC levels of all four Ig classes at presentation which fell during treatment, coincident with normalization of complement values. The biological consequences of IC of various Ig subclasses is discussed with particular reference to a possible mechanism of IgE-IC mediated tissue damage.

Adult↗
PubMed1988

Determination of activated lymphocytes in peripheral blood of patients with multiple sclerosis.

Using monoclonal antibodies Ta1 and CD25 (interleukin-2 receptor: I-2R) and flow cytometry, the levels of activated lymphocytes in the peripheral blood of 50 patients with multiple sclerosis (16 relapsing inactive; 14 relapsing active; 20 chronic progressive) and 20 normal subjects were investigated. No significant differences were observed in the percentage or absolute numbers of Ta1 and IL-2R reactive lymphocytes between the normal and multiple sclerosis patient groups, irrespective of disease activity. Monitoring peripheral blood lymphocytes with respect to these markers would appear to have little value in the management of multiple sclerosis.

Humans↗