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Biomedical subjects

A B Kay

Publications and source records attributed to A B Kay.

At least 145 records · Page 8Linked to original sources
PubMed1994

Effects of prolonged repeated exposure to ovalbumin in sensitized brown Norway rats.

The effects of chronic exposure to ovalbumin (OA) aerosol were studied in Brown Norway rats following intraperitoneal injections with OA and AI(OH)3 and exposure to OA or saline aerosols, once or every third day for 3 to 8 wk. Measurements of airway responsiveness to acetylcholine (ACh) aerosol at 18 to 24 h after allergen exposure showed a significant increase in -logPC150, the concentration of ACh needed to cause a 150% increase in baseline lung resistance, in animals single-exposed or chronic OA-exposed for 3 wk, compared with saline-exposed control animals. The group receiving 8 wk of OA exposure demonstrated no difference from the control animals with -logPC150 lower than that of the two previous groups (p < 0.001). In all three groups, BAL fluid showed a significant increase in neutrophils, but a significant increase in eosinophils (p < 0.01) was only observed in the single-exposed group when compared with saline-exposed control animals. In the 8-wk exposed rats, there was a higher recovery of macrophages and lymphocytes (p < 0.01) compared with control animals and the other two groups. AHR, present after single or 3-wk repeated exposure, disappears by 8 wk of continuous allergen exposure. Both the enhancement and suppression of AHR may be linked to OA-induced immune and inflammatory mechanisms.

Acetylcholine↗
PubMed1994

Topical glucocorticosteroid (fluticasone propionate) inhibits cells expressing cytokine mRNA for interleukin-4 in the nasal mucosa in allergen-induced rhinitis.

Allergen-induced late nasal responses are associated with recruitment and activation of T lymphocytes and eosinophils and preferential mRNA expression for T-helper type 2 (Th2) cytokines. We tested the hypothesis that topical corticosteroids may inhibit late responses by inhibiting cells expressing mRNA for Th2 cytokines. A randomized double-blind placebo-controlled trial of topical corticosteroid (fluticasone propionate) was performed in 48 adult grass pollen-sensitive patients. Nasal biopsies were taken at baseline and repeated 24 hr after local nasal allergen provocation following 6 weeks treatment with either fluticasone propionate 200 micrograms or placebo nasal spray twice daily. Baseline mRNA expression for interleukin-4 (IL-4) (P = 0.01) and IL-5 (P = 0.002) was higher in the patients than in normal controls. Topical corticosteroid treatment significantly inhibited immediate nasal symptoms, with almost complete inhibition of the late response following allergen challenge. This was associated with a marked decrease in the allergen-induced increases in cells expressing mRNA for IL-4 (P = 0.002) but not for IL-5. Inhibition of the late response was also accompanied by decreases in CD25+ cells, presumed T lymphocytes and eosinophils. A significant correlation was observed between the decreases in IL-4 mRNA+ cells and in eosinophils after treatment (r = 0.46, P < 0.05). These results suggest that prolonged treatment with topical corticosteroid inhibits allergen-induced early and late nasal responses and the associated tissue eosinophilia, and that, at least in part, this may result from inhibition of cells expressing mRNA for IL-4.

Administration, Topical↗
PubMed1994

T lymphocytes and mast cells express messenger RNA for interleukin-4 in the nasal mucosa in allergen-induced rhinitis.

We have investigated the phenotype of interleukin-4 (IL-4) mRNA+ cells in the nasal mucosa of six subjects with allergic rhinitis before and 24 hr after local allergen provocation with grass pollen extract. Serial cryostat sections were cut from paraformaldehyde-fixed snap-frozen nasal biopsies, and immunocytochemistry (APAAP) followed by in situ hybridization performed on the same sections. For immunocytochemistry, antibodies against CD3, tryptase, major basic protein (MBP) and CD68 were used to identify T cells, mast cells, eosinophils and macrophages, respectively. Hybridization studies were performed using a digoxigenin-labelled IL-4 riboprobe. Nitroblue tetrazolium (NBT) and X-phosphate-5-bromo-4-chloro-3-indoly phosphate (BCIP) served as chromogens to detect hybridization IL-4 mRNA signals. Significant increases in T lymphocytes and eosinophils and in the number of IL-4 mRNA+ cells were observed after allergen challenge. Double immunocytochemistry/in situ hybridization demonstrated that the majority of IL-4 mRNA+ cells after allergen challenge were CD3+ (73.7% +/- 1.6). Lower numbers of IL-4 mRNA hybridization signals were co-localized to tryptase+ cells (26.0% +/- 1.6). In contrast, no IL-4 mRNA hybridization signals were co-localized to either eosinophils or macrophages. These results indicate that after allergen challenge T cells are the principal cellular source of IL-4 mRNA transcripts during human late nasal responses, with a lesser contribution from mast cells.

Adult↗
PubMed1994

Adhesion to fibronectin primes eosinophils via alpha 4 beta 1 (VLA-4).

Human peripheral blood eosinophils adhered specifically to microtitre plates coated with plasma fibronectin (Fn) in a dose- and time-dependent fashion. Adhesion was optimal at 60 min at a concentration of 100 micrograms/ml. Adherence to Fn was up-regulated by platelet-activating factor (PAF; optimum concentration of 10(-6) M) and was significantly inhibited by a polyclonal anti-Fn antibody (P < 0.05). The following evidence suggested that eosinophil adhesion to Fn was mediated by alpha 4 beta 1: (1) eosinophil adherence to Fn was not inhibited by an Arg-Gly-Asp-Ser (RGDS) synthetic peptide; (2) there was a dose-dependent adherence of eosinophils to microtitre plates coated with the 40,000 MW proteolytic fragment of Fn that contains the CS-1 alpha 4 beta 1 binding region, whereas adherence to the 120,000 MW chymotryptic fragment of Fn, which contains the RGD-dependent binding site, was weak and only observed at high concentrations (> 250 micrograms/ml); (3) significant inhibition of eosinophil adherence to Fn was achieved by monoclonal antibodies (mAb) against the alpha chain of VLA-4 but not by a mAb against CD45 or a mouse myeloma antibody as negative controls. After adhesion to Fn, eosinophils were investigated for their capacity to release leukotriene C4 in response to stimulation with a suboptimal concentration of calcium ionophore (2 x 10(-6) M). Significant enhancement of release was detected with Fn-coated plates but not with the control bovine serum albumin (BSA) (P < 0.01). Furthermore, this enhancement was significantly inhibited by the alpha 4 beta 1 mAb HP2/1 (P < 0.05) but not by an anti-CD45 mAb. From these studies we conclude that (1) alpha 4 beta 1 (VLA-4) integrin is a major receptor for Fn on human eosinophils and (2) adhesion to Fn may prime eosinophils for mediator release during allergic inflammation.

Antibodies↗
PubMed1993

Adhesion to fibronectin prolongs eosinophil survival.

We have investigated the effect of adhesion to fibronectin (Fn) on the survival of eosinophils in culture. Peripheral blood eosinophils from normal human donors were separated by immunomagnetic selection and cultured in RPMI on Fn- (100 micrograms/ml) coated microtiter plates for up to 96 h. Survival was measured by trypan blue exclusion. There was a significant enhancement of eosinophil survival with Fn as compared with both bovine serum albumin-coated and uncoated wells (p < 0.05-0.01). Fn-induced eosinophil survival was comparable to that obtained with exogenous interleukin 3 (IL-3) or granulocyte/macrophage colony-stimulating factor (GM-CSF) and was inhibitable by antibodies against Fn, very late antigen 4 (VLA-4), IL-3, and GM-CSF. Supernatants from Fn-, but not BSA-coated wells contained picogram amounts of IL-3 and GM-CSF, and eosinophils cultured on Fn for 24 h expressed mRNA for GM-CSF as determined by in situ hybridization. Therefore, Fn prolongs eosinophil survival in culture by triggering autocrine generation of cytokines by eosinophils. Since neutrophils lack VLA-4, this could provide a partial explanation for the preferential accumulation of eosinophils at sites of allergic inflammation, as well as the predominant tissue localization of eosinophils in healthy individuals.

Antibodies↗
PubMed1993

Alternative allergy and the General Medical Council.

In July 1992 Dr Keith Mumby, a clinical ecologist, appeared before the professional conduct committee of the General Medical Council on five charges to do with his practice of clinical ecology. He was found guilty of two of the charges--touting for publicity and failing to give a patient adequate medical attention--and admonished. The GMC failed, however, to address the issue of the nature of Mumby's treatments--clinical ecology itself. This is based on the idea that some patients are unusually susceptible to their environment, the diagnosis and treatment are based on an unstandardised provocation-neutralisation test. A variety of medical bodies have failed to find scientific foundation for the technique. The GMC's policy on advertising services to patients is inconsistent, and in this case it has shown a regrettable reluctance to deal with the issue of treatments that are not scientifically validated.

Advertising↗
PubMed1993

Chronic hyperplastic sinusitis: association of tissue eosinophilia with mRNA expression of granulocyte-macrophage colony-stimulating factor and interleukin-3.

BACKGROUND: We investigated the association among tissue eosinophilia, cellular infiltration, and cytokine mRNA expression in chronic hyperplastic sinusitis (CHS). METHODS: Percutaneous biopsies of the maxillary sinuses and nasal polyps were performed in 12 adult patients (six men and six women) of whom seven were nonallergic and 11 were asthmatic. Tissues were compared with biopsy specimens from the inferior and middle turbinates of normal control subjects. RESULTS: Histologically, an eosinophil-predominant inflammatory infiltrate was seen in 10 of 12 patients, whereas a mild to moderate neutrophilic infiltrate was seen in 4 of 12 patients. As determined by immunocytochemistry, diseased tissues and normal control tissues differed significantly in terms of the number of activated (EG2+) eosinophils (p = 0.005) but not in terms of CD3+ or CD4+ T lymphocytes, elastase-positive neutrophils or CD68+ macrophages. The number of eosinophils did not correlate with that of any other cell type. By in situ hybridization, CHS tissues showed significantly higher numbers of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-3 mRNA-positive cells than normal control tissues (p = 0.002 and 0.0005, respectively) per high-powered field. There was a significant correlation between the number of infiltrating EG2+ eosinophils and cells that expressed mRNA for GM-CSF (r = 0.60, p = 0.041) or IL-3 (r = 0.69, p = 0.013). Furthermore, epithelial cells did not show detectable mRNA expression for GM-CSF or IL-3. No significant correlation was found between IL-5 mRNA expression and infiltrating EG2+ eosinophils in diseased tissues. However, the IL-5 density was significantly higher in the five patients with CHS who had positive allergy skin test results than in the seven patients with negative skin test results (p = 0.017) or in normal control subjects. CONCLUSIONS: Our data support a role for GM-CSF and IL-3 in the eosinophilia characteristic of CHS and show that IL-5 mRNA expression is not a prominent feature of nonallergic inflammation. The cellular sources of GM-CSF and IL-3 in CHS remain to be definitely determined.

Adult↗
PubMed1993

Expression of endothelial and leukocyte adhesion molecules interacellular adhesion molecule-1, E-selectin, and vascular cell adhesion molecule-1 in the bronchial mucosa in steady-state and allergen-induced asthma.

BACKGROUND: Interactions between cell adhesion molecules and their ligands are an integral part of inflammatory processes and may have direct relevance to the pathology of asthma. METHODS: Immunostaining with antibodies to cell adhesion molecules was performed on bronchial biopsy specimens from persons with intrinsic and extrinsic asthma, normal nonasthmatic control subjects, and patients with asthma after allergen challenge. RESULTS: There was constitutive expression of intercellular adhesion molecule-1 (ICAM-1), E-selectin and vascular cell adhesion molecule-1 (VCAM-1) in patients with intrinsic and extrinsic asthma and in control subjects. Compared with control subjects, ICAM-1 and E-selectin staining in the submucosa was greater in the intrinsic asthmatic group for intensity (p < 0.02, p < 0.05) and extent (p < 0.01, p < 0.05) of staining, respectively. No differences were observed between patients with extrinsic asthma and normal control subjects, and VCAM-1 expression did not differ among the groups. Epithelial expression of ICAM-1 was more frequent in patients with asthma compared with normal control subjects (p < 0.05). Compared with diluent challenge, bronchial biopsy specimens obtained 24 hours after allergen challenge revealed no significant differences in intensity or extent of staining for ICAM-1, E-selectin, or VCAM-1. After allergen challenge, the intensity and extent of both VCAM-1 and ICAM-1 expression correlated significantly with the number of eosinophils (cells positive for major basic protein). Epithelial ICAM-1 expression was more frequently observed after allergen challenge than after diluent challenge (p < 0.02). CONCLUSIONS: The data suggest a complex pattern of regulation for ICAM-1, E-selectin, and VCAM-1 in vivo, where they may reflect the degree of ongoing inflammation in asthma.

Adult↗
PubMed1993

Relationships among numbers of bronchoalveolar lavage cells expressing messenger ribonucleic acid for cytokines, asthma symptoms, and airway methacholine responsiveness in atopic asthma.

BACKGROUND: We recently demonstrated that T lymphocytes in bronchoalveolar lavage (BAL) fluid from atopic asthmatic patients were activated and expressed increased cytokine messenger ribonucleic acid (mRNA) for "TH2-type" cytokines, particularly IL-4 and IL-5, when compared with those in normal control subjects. This pattern of cytokines may determine the nature of the cellular infiltrate in the bronchial mucosa in asthma and hence the bronchial hyperresponsive (BHR) and symptoms that characterize this condition. METHODS: To examine the association between these cytokines and clinical measures of asthma severity we have extended our studies of BAL cells from subjects with atopic asthma. Numbers of BAL cells with positive in situ hybridization signals for IL-2, IL-3, IL-4, IL-5, granulocyte macrophage colony-stimulating factor (GM-CSF), and interferon-gamma were counted on cytocentrifuge preparations. Results were compared between patients with symptomatic (n = 19) and asymptomatic asthma (n = 10), and associations were sought with airway methacholine responsiveness, resting airway caliber, and asthma symptom scores. RESULTS: There were increased proportions of cells positive for IL-3 (p < 0.05), IL-4 (p < 0.005), IL-5 (p < 0.005), and GM-CSF (p < 0.005) mRNA in BAL fluid from patients with symptomatic asthma when compared with that from subjects free of symptoms, but no difference between the groups in numbers of cells expressing IL-2 and interferon-gamma mRNA. There were significant associations among numbers of cells expressing mRNA for IL-4, IL-5, and GM-CSF, and airflow restriction, BHR, and Aas asthma score. CONCLUSIONS: These findings support the hypothesis that cytokines contribute to airway events that determine asthma symptoms and BHR.

Adult↗
PubMed1993

Activation of CD4+ T cells, increased TH2-type cytokine mRNA expression, and eosinophil recruitment in bronchoalveolar lavage after allergen inhalation challenge in patients with atopic asthma.

BACKGROUND: We have examined whether the local eosinophilia provoked by inhalational allergen challenge of patients with atopic asthma is associated with the appearance, in vivo, of activated TH2-type T helper lymphocytes. METHODS: Fifteen patients with atopic asthma had bronchial wash and bronchoalveolar lavage (BAL) 24 hours after allergen or diluent challenge separated by at least 21 days. RESULTS: There was an increase in eosinophils in both bronchial wash (p = 0.01) and BAL (p = 0.02) after allergen challenge but not after diluent challenge. Activation of CD4+ BAL T cells was suggested by an increase in the expression of CD25 shown by flow cytometry after allergen challenge, when compared with diluent (p = 0.02). There was no evidence of activation of CD8 T cells. By in situ hybridization after allergen challenge as compared with diluent, increases were shown in the numbers of cells expressing mRNA for interleukin-4 (IL-4) (p = 0.005), IL-5 (p = 0.01), and granulocyte-macrophage colony-stimulating factor (p = 0.03) but not IL-3, IL-2, or interferon-gamma. In situ hybridization of BAL cells after immunomagnetic separation of CD2-positive and CD2-negative cell populations showed that IL-4 and IL-5 mRNAs were associated with T lymphocytes after allergen challenge. BAL and bronchial wash eosinophilia closely correlated with maximal late fall in forced expiratory volume in 1 second after allergen challenge. CONCLUSION: Cytokines produced by activated TH2-type CD4+ T cells in the airway may contribute to late asthmatic responses by mechanisms that include eosinophil accumulation.

Administration, Inhalation↗
PubMed1993

Interleukin-8 is a chemo-attractant for eosinophils purified from subjects with a blood eosinophilia but not from normal healthy subjects.

Interleukin-8 (IL-8), a pro-inflammatory cytokine with potent neutrophil chemotactic activity, was studied for its effect on eosinophil migration responses, in vitro. Normal density eosinophils were isolated from healthy, non-atopic subjects (<0.35 x 10(9) eosinophils/l) and individuals with various diseases associated with a blood eosinophilia (range 0.56 x 10(9)-12.2 x 10(9) eosinophils/l). IL-8 produced a dose-dependent migrational response for eosinophils from subjects with an eosinophilia, optimal at 10(-8) M (P < 0.01) and the major component of the migrational response was chemokinesis. On a molar basis, IL-8 (EC50 approximately 10(10) M) was 100-fold more potent than platelet activating factor (PAF), although a comparison of the migrational responses showed that at optimal concentrations IL-8 (10(-8) M) produced only 30% maximal responses stimulated by PAF (10(-6) M). In contrast, IL-8 tested over a wide concentration range had a negligible effect on eosinophils from normal subjects. A direct correlation between the total blood eosinophil counts for all subjects and the absolute magnitude of the migrational response to IL-8 (r = 0.727, P < 0.01 at 10(-8) M), PAF (r = 0.551, P < 0.03 at 10(-6) M) and N-formyl-methionyl-leucyl-phenylalanine (fMLP) (r = 0.689, P < 0.02 at 10(-8) M), suggested that heightened eosinophil migrational responses to inflammatory mediators may arise as a consequence of in vivo priming mechanism(s) associated with the development of an eosinophilia. In this regard, eosinophils derived from human cord blood mononuclear cells cultured in the presence of eosinophilopoietic cytokines IL-3 and IL-5, produced migrational responses to IL-8 and PAF, that were comparable with that of eosinophils from eosinophilic subjects. Furthermore, incubation of eosinophils from normal donors with IL-5 (optimal concentration 10(-9) M), significantly enhanced the subsequent migrational responses to both IL-8 (10(-8) M, P < 0.01) and PAF (10(-8) M, P < 0.05). Therefore, the increased responsiveness of eosinophils from eosinophilic subjects may reflect in vivo priming by IL-5 and this phenomenon may contribute partly to the mechanism(s) by which eosinophils preferentially accumulate at sites of allergic inflammation.

Cells, Cultured↗
PubMed1993

Activated memory T helper cells in bronchoalveolar lavage fluid from patients with atopic asthma: relation to asthma symptoms, lung function, and bronchial responsiveness.

BACKGROUND: Bronchial mucosal inflammation and epithelial damage are characteristic features of asthma. Activation of T helper lymphocytes may contribute to this process by mechanisms including the release of cytokines promoting eosinophil infiltration and activation. METHODS: Bronchial washings and bronchoalveolar lavage fluid were obtained from 29 atopic asthmatic patients (19 with current symptoms and 10 symptom free) and 13 normal volunteers. Flow cytometry was used to assess T cell phenotype and activation status in bronchoalveolar lavage fluid and peripheral blood, and differential cell counts were made on bronchial washings and bronchoalveolar lavage fluid. Findings were related to severity of disease as reflected by symptom scores, baseline lung function, and airway responsiveness. RESULTS: CD4 T lymphocytes in bronchoalveolar lavage fluid and blood from asthmatic patients were activated by comparison with controls (CD4 CD25, median 16.8% v 8.7% for bronchoalveolar lavage fluid, and 15.3% v 8.7% in blood). Bronchoalveolar lavage fluid CD4 T cells from both asthmatic patients and controls were of memory phenotype (95.8% and 96.8% CD45RO and 1.7% and 0.4% CD45RA respectively), whereas both CD45RO and CD45RA T cells were present in blood. Patients with asthma and current symptoms showed increased bronchoalveolar T cell activation compared with patients without symptoms (CD4 CD25 18.7% v 12.3%). Within the asthmatic group there was a significant association between CD4 CD25 lymphocytes and asthma symptom scores (rs = 0.75), airway methacholine responsiveness (log PC20, rs = -0.43) and baseline FEV1 (rs = -0.39). A correlation was also found between CD4 CD25 lymphocytes and eosinophils in bronchoalveolar lavage fluid (rs = 0.48). Eosinophils in bronchoalveolar lavage fluid were increased in asthmatic patients compared with controls and the percentage of eosinophils in bronchoalveolar lavage fluid correlated with asthma symptom score. A relation was found between percentage of epithelial cells in bronchoalveolar lavage fluid and FEV1 and methacholine PC20. CONCLUSION: These results support the hypothesis that selective activation of memory CD4 T cells contributes to eosinophil accumulation, bronchial hyperresponsiveness, and symptoms in asthma.

Adult↗
PubMed1993

CD4 T-lymphocyte activation in asthma is accompanied by increased serum concentrations of interleukin-5. Effect of glucocorticoid therapy.

Peripheral blood mononuclear cells (PBMC) and serum were obtained, on two occasions, from 15 asthmatic patients who required oral glucocorticoid therapy for moderate to severe disease exacerbations. Samples were obtained immediately before commencement of oral glucocorticoids (Day 1) and again after 7 days of treatment (Day 7), when lung function had significantly improved. Samples were also isolated on two occasions 7 days apart from a group of seven untreated volunteers. Expression of CD25, human lymphocyte antigen (HLA-)DR, CD45RA, and CD45RO on CD4 and CD8 T lymphocytes was measured by flow cytometry, and serum concentrations of interleukin-5 (IL-5) were measured using an enzyme-linked immunosorbent assay technique. On Day 1 the asthmatic patients showed significantly higher percentages, as compared with the control subjects of CD4 T lymphocytes expressing the markers CD25, HLA-DR, and CD45RO and significantly lower percentages of CD4 T cells expressing CD45RA. After glucocorticoid therapy, the percentages of CD4 T cells expressing CD25, HLA-DR, and CD45RO were significantly reduced in the asthmatic patients, and the percentages of those expressing CD45RA significantly increased so that by Day 7 expression of all four markers was no longer significantly different from that of the control subjects. By contrast, the percentages of CD8 T cells expressing HLA-DR, CD45RA, and CD45RO in the PBMC of the asthmatic patients on Day 1 were not significantly different from those in control subjects, whereas the percentages of CD25 expressing CD8 T cells were only marginally elevated. Glucocorticoid therapy resulted in no significant change in the expression of all four markers on CD T cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Prednisolone treatment in asthma is associated with modulation of bronchoalveolar lavage cell interleukin-4, interleukin-5, and interferon-gamma cytokine gene expression.

Although corticosteroids are effective in improving asthma symptoms and bronchial responsiveness, their mechanism of action is unknown. We examined whether changes in bronchial responsiveness with corticosteroid therapy of asthma are accompanied by a reduction in cytokine gene expression and eosinophil infiltration in the airways. Bronchoalveolar lavage (BAL) was performed in 18 patients with moderate asthma before and after 2 wk of treatment with prednisolone, 0.6 mg/kg/day, or matched placebo in a randomized double-blind parallel group study. Cells were counted in BAL cytocentrifuge preparations, and the numbers of cells expressing cytokine mRNA were assessed by in situ hybridization using 35S-labeled RNA probes. When the actively treated and placebo groups were compared, there was a decrease in airway methacholine responsiveness (p < 0.01) after prednisolone. This was accompanied by a decrease in bronchoalveolar lavage eosinophils (p < 0.05), a reduction in the numbers of BAL cells per 1,000 expressing mRNA for interleukin-4 (IL-4, p < 0.01) and interleukin-5 (IL-5, p < 0.005), and an increase in numbers of cells expressing mRNA for interferon-gamma (p < 0.005). These results are compatible with the hypothesis that the beneficial effects of corticosteroids in asthma may result from modulation of cytokine production, with consequent inhibition of local bronchial eosinophilia.

Adult↗