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Biomedical subjects

L Enerbäck

Publications and source records attributed to L Enerbäck.

At least 37 records · Page 2Linked to original sources
PubMed1994

Application of an immunocolloid gold technique for the ultrastructural demonstration of IgE-receptor complexes on rat mast cells.

In previous works using cytofluorometry, we demonstrated a broad range of IgE and IgE-receptor levels within individual mast cell populations with a 60 to 80% occupancy of the IgE receptors on mast cells by native IgE. This study was performed in order to confirm our previous findings using an independent method and to visualize the distribution of IgE-receptor complexes on mast cells at an ultrastructural level. For this purpose an indirect immunocolloidal gold-labelling technique has been applied. By counting the number of labelled gold particles, a relative measure of IgE-receptor surface expression and IgE occupancy of the receptors could be obtained. With respect to mast cell morphology and anti-IgE binding specificity criteria, 1% glutaraldehyde + 4% paraformaldehyde (1:1, vol/vol) was found to be the best of the seven fixatives applied in this study. This technique revealed numerous gold particles on the surface of mast cells from barrier-maintained rats (26 +/- 11 per mast cell section, mean +/- SD). Increased numbers of gold particles were counted if the mast cells were incubated with rat myeloma IgE (20 micrograms/ml) (46 +/- 33 per mast cell section, mean +/- SD). There were significantly increased numbers of gold particles on the mast cells of rats infected with N. brasiliensis (126 +/- 30 per mast cell section, mean +/- SD). This indicates that some of the IgE receptors (about 50% of the total number of IgE receptors in this case) on mast cells were occupied by native IgE and that parasite infection significantly increased the number of IgE molecules on the surface of the mast cells. These results correspond with the findings we have made using the cytofluorometric technique and confirm the large individual variations in the density of IgE receptors and IgE among the mast cells of a given cell population. Macrophages, lymphocytes and eosinophils, carrying the low-affinity IgE receptors (Fc epsilon RII), contained less than 5 (normal rats after incubation in rat IgE) or 10 (nematode-infected rats) gold particles per cell section. We also observed some non-granulated lymphocyte-like cells which bound a large number of gold particles after incubation with rat myeloma IgE (20 micrograms/ml), indicating that they contained IgE receptors Fc epsilon RI). They were interpreted as mast cell precursors which have previously been shown to exist in the peritoneal cavity.

Animals↗
PubMed1994

IgE receptors, IgE content and secretory response of mast cells in athymic rats.

Athymic, nude (Lewis rnu/rnu) and normal (Lewis +/+) rats were used to study the T-cell dependence of the regulation of IgE receptors and IgE content on mast cells in vivo. We estimated the number of IgE receptors and the IgE content on peritoneal mast cells using a cytofluorometric technique. The secretory capacity of the mast cells was measured in terms of histamine release as a function of anti-IgE concentration by incubation with antibodies in vitro. Two groups of rats, aged 6 and 13 weeks, were examined. The mast cells of the rats belonging to the older age group (both normal and athymic) had a higher total protein (equivalent to dry mass or size) and mediator content (heparin, histamine and 5-hydroxytryptamine) in accordance with previous findings. Mast cells of the athymic rats of both age groups contained similar levels of IgE receptors and IgE and did not differ in these respects from those of the normal rats. Of the IgE receptors available for binding, about 80% were occupied by IgE in mast cells of normal and of athymic rats in both age groups. The anti-IgE-induced histamine release of the mast cells was, however, significantly lower in athymic rats compared to the normal controls. A change in housing from barrier-maintained to conventional conditions for 2 weeks enhanced the IgE-receptor and IgE content, as well as the releasability of histamine of the mast cells of both athymic and normal rats. The basal level of IgE occupancy of the receptors on mast cells was therefore not impaired in the athymic rats, as might be inferred from previous findings of a T-cell dependence of the IgE immune response. The results further indicate that T-lymphocyte-derived cytokines appear not to be required for either the expression of IgE receptors or for their ability to acquire IgE on mast cells, but such factors seem to enhance the release of histamine following the cross-linkage of the IgE receptor on mast cells in normal conditions.

Aging↗
PubMed1993

A novel large granular lymphocyte-like cell isolated from IL-2-supplemented murine intestinal lamina propria lymphocyte cultures with potent inhibitory action on lymphocyte proliferation.

Regulation and control of the local immune system in the gut mucosa are poorly understood phenomena. Recently we observed in whole alpha-CD3-driven, IL-2-supplemented, lamina propria (LP) T cell cultures that pronounced anergy developed concomitant with the appearance of large granular lymphocyte (LGL)-like cells. The LGL-like cells did not appear in the cultures in the absence of alpha-CD3 activation. These cells expressed Thy 1.2, NK1.1, AsGM1, CD3, and most often CD8 but were always negative for CD4. They exclusively required IL-2 to proliferate and survive in culture and several cell lines were established. Analysis of the regulatory ability of these cells on immune responses revealed that the gut LGL-like cells strongly inhibited T as well as B cell proliferation by releasing a soluble factor(s). Subsequent detection in the culture supernatants of cytokines with reported inhibitory properties on lymphocyte proliferation, interferon-gamma, and transforming growth factor beta correlated poorly to the inhibitory action of the supernatants. Despite the NK-like nature of these cells no or weak cytotoxic activity could be detected against Yac-1 target cells. The LGL-like cells expressed Fc receptors for IgE and demonstrated properties in EM and cytochemical analysis which resembled mucosal mast cells, but unlike such cells the LGL-like cells did not contain histamine or serotonin. The lamina propria of normal mouse small intestine was found to contain cells with morphology and staining pattern similar to those of cultured LGL-like cells, i.e., double-positive for Thy 1.2 and NK 1.1. We propose that this novel intestinal LGL-like cell, probably of T cell origin, may act as a potent suppressive cell in mucosal immune responses exerting a regulatory function on T cell activities and preventing adverse inflammatory reactions in the intestinal mucosa. Therefore, we suggest that these cells may be referred to as granulated inhibitory lymphocytes (GIL) cells. The lamina propria GIL cells exhibit many similarities to the recently described immunosuppressive decidual LGL cells in the placenta.

Animals↗
PubMed1993

Mast cells and mediators in the nasal mucosa after allergen challenge. Effects of four weeks' treatment with topical glucocorticoid.

The study focuses on the relationship between the tissue density of mast cells, the tissue histamine levels and the levels of markers of mast cell activation after an allergen challenge of the nasal mucosa of allergic patients. The effect of 4 weeks' treatment with a topical glucocorticoid, fluticasone propionate, was studied in a double-blind, placebo-controlled study of 25 hay fever patients. Nasal biopsies were obtained before and after the treatment period for the evaluation of mast cell density and tissue histamine levels. Nasal challenges were performed at 2-week intervals for 8 weeks using a standardized nasal lavage model. TAME-esterase was analysed in the returned lavage fluid from all the challenges (weeks 0-8), while the levels of histamine and tryptase were analysed in lavage fluids from challenges performed before and after the treatment period (weeks 0 and 4). The symptoms of nasal allergy were assessed after each challenge. Treatment with fluticasone propionate did not influence mast cell density, the tissue histamine concentration, the lavage histamine levels or the TAME-esterase activity, while a reduction in nasal symptoms and tryptase in nasal lavage fluid was revealed. Our present study again emphasizes the fact that the mast cell is an important trigger cell in the immediate nasal allergic response. The study also demonstrates the usefulness of the measurements of tryptase as an indicator of both mast cell activation and the efficacy of topical steroid treatment.

Administration, Topical↗
PubMed1993

Mast cells and biogenic amines in radiation-induced pulmonary fibrosis.

Sprague-Dawley rats were exposed to a single X-ray dose of 30 Gy over the lungs and examined at 1-wk intervals during the following 3 to 8 wk. Mast cells were counted after specific staining with toluidine blue at a low pH and the mast-cell amines, histamine (Hi) and serotonin (5-HT), were measured using high-performance liquid chromatography. Irradiation induced pneumonitis followed by pulmonary mast-cell hyperplasia and progressive fibrosis 4 to 8 wk after irradiation. By week 4, immature-looking mast cells with a few granules started to appear, followed by a gradual increase in mast cells that reached very high levels after 8 wk, up to 40 to 200 times the normal. The pulmonary Hi and 5-HT content increased concomitantly from 6 and 1 micrograms/g to a maximum of 200 and 18 micrograms/g, respectively. These high levels of amine content and mast-cell densities greatly exceed those of any normal tissue. There was a strong correlation between the Hi and 5-HT content in both normal (r = 0.87) and irradiated (r = 0.93) lung tissue, as well as between the mast-cell density and amine content after irradiation (r = 0.86), thereby indicating that both amines derived from mast cells. The Hi/5-HT quotients were much lower in both normal and irradiated lung tissue (5 and 9, respectively) than in other tissues where these amines are stored in mast cells, or in isolated peritoneal mast cells (43). This relatively higher 5-HT content in pulmonary mast cells suggests that this amine performs a specific function in the lung.

Animals↗
PubMed1992

Mast cells and eosinophils in the allergic mucosal response to allergen challenge: changes in distribution and signs of activation in relation to symptoms.

An allergen challenge was performed in 10 asymptomatic patients with strictly seasonal allergic rhinitis. For comparison; seven nonallergic subjects were challenged with allergen, and seven allergic patients were challenged with diluent. Cell samples, obtained with use of a brush technique to recover cells from within the epithelium and nasal lavage to collect cells from the epithelial surface, and symptom scores were taken before challenge and at 2-hour intervals during 12 hours. The cell suspensions were cytocentrifuged onto object slides for light microscopy. Histamine was determined in the cell pellets. In brush samples from the allergic patients challenged with allergen, eosinophils, expressed as a percentage of the total granulocytes, increased from 4.3% +/- 2.7% (mean +/- SEM) to 10.3% +/- 3.8% (p < 0.05) 4 hours after challenge. This level was maintained for up to 12 hours. A similar increase was noted in the lavage specimens 2, 6, and 8 hours after the challenge. In the brush samples the proportion of eosinophils containing two or more cytoplasmic vacuoles, taken as a sign of activation, increased from 20% to 72% (p < 0.05) 8 hours after provocation. In brush samples from the allergic patients challenged with allergen, the numbers of metachromatic cells increased to a maximum of eightfold at 10 hours. In the lavage specimens, no metachromatic cells were observed before provocation, but they progressively increased in number 2 to 12 hours after provocation. Cell pellet histamine content decreased temporarily 2 to 4 hours after challenge (p < 0.05) in brush samples from allergen-challenged allergic patients. The local metachromatic cell density before challenge, as reflected in the brush specimens, correlated with nasal congestion, sneezing, and the degree of eosinophilia.

Adult↗
PubMed1990

DNA content and nuclear size of megakaryocytes in thrombocythaemia.

Total nuclear DNA content and nuclear size of megakaryocytes were studied in biopsies of the iliac bone marrow of individuals with normal or increased platelet counts. The DNA content was determined using Feulgen cytophotometry of bone marrow smears and the nuclear area by morphometric analysis of megakaryocytes of bone marrow sections. The mean DNA content and the mean nuclear area were both significantly larger in megakaryocytes of patients with thrombocytosis as a result of myeloproliferative disease than in patients with secondary thrombocytosis as well as in two control groups of individuals with normal platelets counts, one comprising healthy volunteers, the other with various non-haematological disorders. There was a statistically significant correlation between the DNA content and nuclear area of the megakaryocytes (r = 0.92) in the entire group of bone marrows studied.

Adolescent↗
PubMed1990

Mast cells, tissue histamine and eosinophils in early- and late-phase skin reactions: effects of a single dose of prednisolone.

Skin prick tests with allergen and histamine were performed on the volar aspect of the forearms in a double-blind, cross-over study with 40 mg of prednisolone and placebo in 16 pollen-allergic subjects. Skin biopsies were taken before any treatment and 15 min (group 1; n = 8) and 6 h (group 2; n = 8) after local challenge with allergen, corresponding to the timing of an early- and late-phase reaction. The specimens were used for the histological evaluation of mast cell and eosinophil density as well as for the determination of the histamine and protein content. The size of the induced weal and flare area as well as of any late-phase reaction was determined using digitized planimetry. The single dose of prednisolone, given 2 h prior to challenge, did not affect the size of the weal and flare response. Only 4 of the individuals developed a visible late-phase response. Eosinophils were virtually absent before allergen exposure, but were already present 15 min after allergen challenge, largely associated with the blood vessels, and were numerous at 6 h. There was, however, no relationship between eosinophil density and the presence or extent of any visual late phase. The mast cells/basophils showed a tendency to increase at the 6-hour determination. The infiltration of eosinophils was blocked by the glucocorticoid. This treatment also induced a difference in the mast cell density at the 6-hour determinations, associated with a similar difference in the histamine content of the biopsy specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The mast cells.

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Animals↗
PubMed1989

Histamine and mucosal mast cells in interstitial cystitis.

Interstitial cystitis (IC) is a chronic inflammatory disorder of the urinary bladder of unknown aetiology and pathogenesis. The classic form (Hunner's ulcer) is characterized by high mast cell numbers in the detrusor muscle and an expansion of mucosal mast cells in the lamina propria and also in the epithelium. Such cells can be recovered in bladder washings and in the urine in single cell suspensions. We have counted the mast cells and measured the histamine in bladder washings from 16 patients with classic IC and from a control group of 15 patients with so-called early, non-ulcerative IC. The bladder washings from all patients with classic IC contained well preserved mast cells (median 2.16, range 0.5-8.6 x 10(3) cells/I) and histamine (median 14.3, range 6-66 ng/l), while only occasional mast cells and traces of histamine were found in washings from patients with non-ulcerative IC. The histamine content was strongly correlated to the number of mast cells (r = 0.87). The mean histamine content per mast cell was estimated at 7.6 +/- 0.65 (SEM) pg/cell. The high histamine content per mast cell in relation to previously published data (2.8-4.6 pg/cell) can be attributed to the mild and rapid handling of the specimens.

Adult↗
PubMed1989

Prolonged treatment with topical glucocorticoids results in an inhibition of the allergen-induced weal-and-flare response and a reduction in skin mast cell numbers and histamine content.

The inhibitory effects of topical glucocorticosteroid treatment on the immediate dermal allergic reaction were studied in 10 patients in a double, randomized, placebo-controlled fashion. The aim was to study whether a prolongation of the treatment time would enhance the inhibitory effect beyond the 30-40% reduction previously reported after 1 week of treatment, and whether any changes in skin reactivity were accompanied by changes in the level of mast cells or histamine at the challenge site. Allergen and histamine skin-prick tests were performed on both forearms before the start of the study and after 2 and 4 weeks of treatment with placebo cream on one forearm and with 0.05% clobetasol-17-propionate cream on the other. Punch biopsies from the skin treated actively and with placebo were taken after 4 weeks in eight of the patients. The specimens were used for the light-microscopic evaluation of mast cell density and for the measurement of histamine and protein content. After 4 weeks of treatment we found a reduction in the allergen-induced weal (72%; P less than 0.001) and flare (62%; P less than 0.05) response. There was also a minor reduction in the histamine-induced weal (38%; P less than 0.05) but not the flare response, suggesting that the glucocorticoid treatment induced a reduced mediator release at allergen challenge. This could be partially explained by the finding of a reduction in the number of detectable skin mast cells (85%; from 0.78 to 0.11 mast cells per unit area) and in the histamine content of the skin as related to the tissue wet weight (36%; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Nasal mast cell response to natural allergen exposure.

A redistribution of mast cells into the epithelium and towards the mucosal surface was previously observed during the allergy season in individuals allergic to birch pollen. We have therefore attempted to investigate in greater detail the role of mast cells in mucosal allergy by the study of the morphological and biochemical changes that occur in the nasal mucosa of allergic individuals during natural allergen exposure. An activation of the intraepithelial mast cells was indicated by the observation of ultrastructural signs of a secretory activity. We also found that the normal strong correlation between mast cell numbers and histamine content in the nasal mucosa was absent in specimens taken during allergen exposure, which was interpreted as a result of a release of histamine from the mast cells with the appearance of a transient, non-mast cell pool of tissue histamine. Furthermore, the histamine content of the nasal mucosa during the pollen season was strongly correlated to the severity of symptoms experienced by the patients. These observations provide additional evidence that mucosal mast cells have a pathogenetic role in continuous allergic airway disease.

Allergens↗
PubMed1989

Nasal mucosal response to repeated challenges with pollen allergen.

In order to explore the dynamics of the cellular response of the airway mucosa to allergen exposure, controlled daily allergen challenges were performed for 7 days during the pollen-free winter months in nine patients with strictly seasonal allergic rhinitis caused by birch pollen allergen. Symptoms obtained after the challenge were related to morphologic changes within and on the surface of the nasal mucosa. Cell samples were obtained daily prior to challenge from the nasal mucosa using mucosal imprints on plastic strips, brush samplings from the nasal mucosa, and nasal lavage. For light microscopy, the cellular material obtained by brushing and nasal lavage were cytocentrifuged onto object slides. Histamine was measured in the cell pellets that were obtained using the lavage and brush procedures as well as in the lavage supernatant fluid. Four symptoms (sneezes, itching, secretion, and blockage) were recorded and expressed individually as well as in the form of a composite symptom score. Nasal blockage was measured using a nasal peak flow meter. The patients displayed an increase in nasal symptoms after the allergen challenge, which was further increased between Days 2 to 7 (p less than 0.05). The light microscopic evaluation of the lavage revealed an immediate increase in eosinophils from 2.3 to 13.1% and was maintained on the same level throughout the period of challenges. A similar increase was noted in the brush specimens, and a strong correlation was obtained between these two methods of sampling.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intranasal↗
PubMed1989

Effect of nedocromil sodium on the compound exocytosis of mast cells.

The secretory activity of peritoneal mast cells was studied in vitro after challenge with compound 48/80 of cells obtained from normal rats and with anti-rat IgE of cells obtained from rats hyperimmunised with Nippostrongylus brasiliensis. Peritoneal mast cells were isolated from 2 groups of rats aged 2 to 3 months and 5 to 6 months. After purification, the cells were preincubated with or without nedocromil sodium for 5 minutes followed by addition of secretagogue and incubation for an additional period of 5 minutes (compound 48/80) or 15 minutes (anti-IgE). The secretory response was analysed by measurement of the release of endogenous histamine and serotonin (5-hydroxytryptamine) into the medium using high performance liquid chromatography, and by the assay of the heparin content of individual mast cells by cytofluorometry, using the fluorescent dye berberine as a quantitative marker. Concentrations of secretagogues which gave 30 to 40% amine release in controls without inhibitor were selected. In agreement with previous reports, the degree of release of histamine was slightly higher than that of serotonin, but nedocromil sodium suppressed the release of both amines in a parallel manner, without any differential effect, after stimulation with both compound 48/80 and anti-IgE. The effect of nedocromil sodium was concentration-dependent, with the lowest effective concentration in the range of 10(-8) to 10(-7) mol/L, and reduced release to about 40% of control values. Mast cells from young rats responded with a significantly higher amine release than mast cells from old rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1988

A brush method to harvest cells from the nasal mucosa for microscopic and biochemical analysis.

A method is described for the sampling of epithelial cells and other effector cells from the human airway mucosa for structural and biochemical analysis. The cell samples are obtained from the nasal mucosa using a small nylon brush which is rotated over the epithelium and soaked and shaken in a small volume of a balanced salt solution. Morphological evaluation using light microscopy and transmission electron microscopy revealed excellently preserved cytological detail. In asymptomatic individuals the cells harvested were as follows: 45 +/- 5.9% (mean +/- SEM) epithelial cells, 38 +/- 7.1% granulocytes, 16 +/- 2.3% large mononuclear cells (monocytes), and 1.3 +/- 2.3% eosinophils. Repeated measurements in the same individual revealed a coefficient of variation of the order of 40% for the proportions of cells harvested. In comparison with nasal airway lavage, a higher proportion of epithelial cells and monocytes were obtained with the brush method. The cells harvested could also be used for biochemical analysis. The histamine content of the cell pellets was found to be strongly correlated with the mast cell count (r = 0.93) and was estimated to about 10 pg/cell, which is higher than previously reported for mast cells obtained from human lung tissue dispersed by an enzymatic method. The present method appears to be appropriate for the study of cellular events in the nasal mucosal epithelium.

Adult↗
PubMed1988

Identification of oversulphated galactosaminoglycans in intestinal-mucosal mast cells of rats infected with the nematode worm Nippostrongylus brasiliensis.

The oversulphated galactosaminoglycans synthesized by rat mucosal mast cells were isolated from the small intestine of animals infected with the nematode Nippostrongylus brasiliensis, which causes proliferation of these cells. The 35S-labelled polysaccharides were degraded by digestion with chondroitinase ABC, and the structures of the disaccharide products were determined by cleavage with mercuric acetate followed by electrophoretic characterization of the resultant sulphated monosaccharides. It was concluded that about half of the disulphated disaccharide units in the polysaccharide consisted of chondroitin sulphate E-type structures [GlcA-GalNAc(4,6-di-OSO3)], in which both sulphate groups were located on the N-acetylgalactosamine unit. The remainder consisted of isomeric structures with one sulphate group on the N-acetylgalactosamine residue and one on the hexuronic acid unit and presumably represented the dermatan sulphate-type sequence [IdoA(2-OSO3)-GalNAc(4-OSO3)].

Animals↗