PubMed Health⌕ Search

Biomedical subjects

L Enerbäck

Publications and source records attributed to L Enerbäck.

At least 55 records · Page 3Linked to original sources
PubMed1988

Phenotypic expression of proteoglycan in mast cells of the human nasal mucosa.

The phenotypic expression of the proteoglycan of human mast cells in the nasal mucosa and normal skin was analysed using histochemical techniques. Nasal mucosa was obtained from normal subjects, from patients with seasonal allergic rhinitis before and during the pollen season and from patients with nasal polyps. In the latter groups, specimens were taken from both polyp tissue and adjacent nasal mucosa. Formaldehyde treatment blocked the cationic dye binding in 75-84% of the mast cells located in the nasal mucosa, as compared to the optimum fixation with IFAA (iso-osmotic formaldehyde-acetic acid). A significantly lower degree of blocking of dye binding was obtained in the human skin where 45% of the mast cells were susceptible to formaldehyde treatment (P less than 0.01). The mast cells of the polyp tissue also showed a relatively low degree of blocking (54%), which was significantly lower than the blocking of mast cells of the nasal mucosa taken from the same individuals (P less than 0.05). Staining of serial tissue sections in Alcian Blue containing graded concentrations of MgCl2 was used to determine the critical electrolyte concentration (CEC) of the dye binding, defined as the salt concentration at which the staining of 50% of the mast cells is extinguished. The CEC of the skin mast cells was 0.64M MgCl2 which is significantly higher than that of the mast cells of the nasal mucosa of normal subjects [0.49M (P less than 0.05)], allergic subjects [0.52M (P less than 0.01)], patients with polyp disease [0.52M (P less than 0.01)] and the polyp tissue proper [0.57M (P less than 0.05)].(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Histochemical heterogeneity of dermal mast cells in athymic and normal rats.

Mucosal mast cells (MMC) and connective tissue mast cells (CTMC) of the rat contain different proteoglycans, which can be distinguished using histochemical methods. The chondroitin sulphate proteoglycan of the MMC, unlike the heparin of the CTMC, does not show fluorescent berberine binding, is susceptible to aldehyde fixatives and stains preferentially with Alcian Blue in a staining sequence with Safranin. The majority of the dermal mast cells are typical CTMC and are located in the deep part of the dermis. Subepidermal mast cells are comparatively few in normal rats but numerous in athymic rats and mice. These cells differ from other dermal mast cells in that they stain preferentially with Alcian Blue and they appear to contain little histamine. We examined some of the histochemical properties of the skin mast cells of female PVG-rnu/rnu rats and their heterozygous littermates aged from 5 to 29 weeks. The thiazine dye-binding of the subepidermal mast cells was partially blocked by formaldehyde fixation and only about half of them showed a weakly fluorescent berberine binding. The critical electrolyte concentration of the Alcian Blue staining of the subepidermal mast cells was between that of CTMC and MMC. Deaminative cleavage with nitrous acid abolished the staining of all skin mast cells, while that of the MMC was unaffected. There were no statistically significant differences in the staining patterns of the dermal mast cells between different ages or groups of rat. These results indicate that the subepidermal mast cells contain a heparin proteoglycan which is, however, different from that of the typical CTMC of other sites. They thus appear to represent a second example of a mast cell within a defined anatomical location exhibiting a distinct proteoglycan expression.

Animals↗
PubMed1988

Secretory activity of nasal mucosal mast cells and histamine release in hay fever.

Although theoretical considerations and experimental evidence implicate the mast cells in the pathophysiology of the immediate type hypersensitivity reaction, the evidence of their active participation in human allergic disease is still fragmentary. We have therefore sought evidence of mast cell activation in allergic mucosal disease using strictly seasonal allergic rhinitis as a model. Twelve patients with birch pollen-induced hay fever were examined before and well into the birch pollen season. Allergen exposure was monitored by pollen counts and the degree of symptoms registered daily. Small surgical biopsies and mucosal imprints were obtained from each patient before and during the season. Mast cells were analysed by light and electron microscopy and mucosal histamine was measured using a sensitive HPLC assay. We found a reduction in the number of mast cells in the nasal mucosa during pollen exposure (p less than 0.05) but no significant reduction of the histamine content. There was a correlation between the nasal mucosal mast cell density and histamine content before the pollen season (r = 0.76; p less than 0.01), but no such correlation was found during the period of pollen exposure (r = 0.19; n.s.). This finding points to secretory activity by the mast cells during the pollen season and to the appearance of a non-mast cell pool of tissue histamine. Evidence for a secretory activity of the mast cells during the pollen season was also confirmed by electron microscopy. In addition, we found a strong correlation (r = 0.77; p less than 0.01) between the histamine content of the nasal mucosa during the pollen season and the degree of nasal symptoms. The number of epithelium-associated mast cells found on mucosal imprints prior to the pollen season showed a strong correlation with the symptoms experienced later during the period of pollen exposure (r = 0.83; p less than 0.01). Taken together these observations indicate that the mast cell has a pathogenetic role in continuous allergic airway disease and re-emphasizes the role of histamine in the induction of the symptoms of allergic rhinitis.

Adult↗
PubMed1987

Mucosal mast cells in the rat and in man.

The proteoglycan structure of mucosal mast cells (MMC) of the two species has been analyzed with histochemical in situ techniques. The findings indicate that human MMC, like human mast cells of several other sites, contain a heparin proteoglycan, unlike rat MMC which lack heparin but contain an oversulphated chondroitin sulphate. However, the dye-binding of the human MMC proteoglycan, like that of the rat, is highly susceptible to blocking by formaldehyde. Human MMC also exhibit a lower critical electrolyte concentration (CEC) of dye-binding than mast cells of other connective tissue sites, suggesting a relatively lower charge density and/or molecular weight of the glycosaminoglycan of the MMC. These findings thus suggest that the human MMC like those of the rat have a distinctive proteoglycan structure. Recent findings of another group indicate that the human MMC like those of the rat have also a distinctive proteinase composition. Finally, the mast cell response of the nasal mucosa during birch pollen allergy shows fundamental similarities to the nematode response of the rat intestinal mucosa. During both conditions mast cells are redistributed from the lamina propria into the epithelium, probably as a result of migration of mast cells or mast cell precursors. Taken together, these findings suggest the existence of a distinctive MMC phenotype also in man.

Animals↗
PubMed1987

Nasal mucosal mast cells and histamine in hay fever. Effect of topical glucocorticoid treatment.

Symptomatic seasonal allergic rhinitis has previously been found to be associated with a redistribution of mast cells from the subepithelial stroma to the epithelial lining and the surface of the nasal mucosa. The present study was designed in order to elucidate the interaction between topical glucocorticosteroids, effective in the treatment of allergic rhinitis, and the migration of mast cells described earlier. Six patients treated prophylactically in the nose with budesonide were studied. Imprints and biopsies from the nasal mucosa were taken 2-3 weeks before and 2-3 weeks into the birch pollen season. The biopsies were used for light microscopy and tissue histamine determination. The morphologic studies showed, also in the actively treated patients, an increased number of metachromatically stained cells on the nasal mucosal surface of the same order of magnitude as previously reported for untreated patients. We did, however, find a decrease in the histamine content of the nasal mucosa, which was not associated with a decrease in the number of mast cells. Together with similar previous findings in the unstimulated allergic nasal mucosa these results suggest that glucocorticosteroids induce a decrease in the mast cell histamine pool, possibly due to an inhibition of the intracellular synthesis of histamine. This effect might contribute to the clinically beneficial effect of topical glucocorticosteroids in the treatment of hay fever.

Administration, Topical↗
PubMed1986

Histamine content and mast cell numbers in tissues of normal and athymic rats.

Tissue histamine levels and mast cell numbers were determined in the skin, tongue and jejunum of female rnu/nu and rnu/+ rats aged between 5 and 29 weeks. The tongue and jejunal mucosa of rnu/nu rats had a larger mast cell density and histamine content than rnu/+. There was a marked increase in subepithelial mast cells in the skin of rnu/nu rats compared with their normal littermates, while mast cell numbers in the deep skin layer and the histamine content were similar in the two groups of rat. Subepithelial skin mast cells were smaller, of more variable shape and contained fewer granules than mast cells in the deep dermal layer, and, unlike the latter, did not emit a yellow fluorescence after treatment with o-phthalaldehyde. The results indicate that the bulk of the skin histamine is contained in mast cells residing in deep skin layers. They also support the view that the thymus may have a suppressive effect on both mucosal and connective tissue mast cells in vivo.

Aging↗
PubMed1986

Non-differential inhibition of histamine and serotonin release from mast cells by amitriptyline.

A differential amine release from mast cells induced by an inhibitory effect of the antidepressant drug amitriptyline on the release of histamine but not on that of serotonin has recently been reported. In view of the potential biological importance of a differential release of mast cell amines we have studied the effect of amitriptyline on the dynamics of the secretory process using a combination of vital berberine staining (demonstrating intracellular granules that have released amines) and measurement of histamine, serotonin (5-HT), and heparin release. The results show a non-differential inhibition of the release of histamine and 5-HT by amitriptyline. The basic pattern of the secretory process, studied in terms of granule extrusion and amine release from intracellular granules, was unaffected by the drug.

Amitriptyline↗
PubMed1986

Histamine and mucosal mast cells in gluten enteropathy.

Coeliac disease is a malabsorptive disorder caused by intolerance to gluten and is characterized by a remodelling of the intestinal mucosa including villus atrophy, crypt hyperplasia and net increase of mucosal volume. Changes of the number of mucosal mast cells (MMCs) in coeliac mucosa has recently been reported, suggesting that the mast cell activity could have a pathogenetic role in gluten enteropathy. MMCs located solely in the lamina propria are the main repository for small-gut mucosal histamine. A consecutive prospective study was designed to study the histamine content, MMC numbers, and the relative volume of lamina propria in intestinal biopsies from adult patients suffering from unexplained diarrhea and/or malnutrition. Histamine was measured by a HPLC-method, the number of MMC was counted after long toluidine-blue staining, and the relative volumes of lamina propria and epithelium were estimated morphometrically. The findings were correlated to the histopathological appearance of the mucosa. As compared to controls the histamine content increased by 80% and MMC numbers by about 60% in the coeliac mucosa. There was also a correlation between MMC numbers and histamine content for both normal and coeliac mucosae (r = 0.81). The morphometric estimation of the relative volumes of epithelium and lamina propria revealed that the lamina-propria compartment was increased by approximately 40% in coeliac mucosa. Taking the changes in compartmental volumes of the remodelled coeliac mucosa into account, our results suggest that the histamine content and MMC population were significantly increased. MMC and MMC-associated histamine may therefore be involved in the pathogenesis of gluten enteropathy.

Celiac Disease↗
PubMed1986

Intraepithelial migration of nasal mucosal mast cells in hay fever.

Mast cells were studied by light microscopy in mucosal imprints and in biopsies of nasal mucosa of 12 birch pollen allergic individuals before and during the pollen season, using techniques optimized for the demonstration of mucosal mast cells. We also measured the histamine content of nasal mucosa, whole blood and plasma, and counted the numbers of circulating blood basophils. Before the pollen season the nasal mucosa was found to contain many mast cells located in the mucosal connective tissue stroma, and very few cells with basophilic and metachromatic granules were found in mucosal imprints. During the pollen season there was a redistribution of mast cells into the epithelium, many such cells now being recovered in mucosal imprints. The total number of mucosal mast cells counted in tissue sections did not change significantly with the onset of the pollen season, suggesting a redistribution of mucosal mast cells by migration. Judged by morphologic appearance and naphthol-AS-D chloroacetate esterase activity, the intraepithelial mast cells found in tissue sections had rather the properties of tissue mast cells than of blood basophils, and only a few of the basophilic cells of the imprints had a morphology compatible with blood basophils. The histamine content of the mucosa, as well as histamine levels of whole blood and plasma, and circulating blood basophil numbers did not change significantly in relation to the pollen season. These findings suggest that an intraepithelial migration of mucosal mast cells is part of the allergic mucosal response.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Intraepithelial migration of mucosal mast cells in hay fever: ultrastructural observations.

Evidence has been presented suggesting that a migration of nasal mast cells from the mucosal connective tissue stroma into the epithelium is part of the mucosal response in birch pollen allergy. In a previous study, the identification of these intraepithelial cells as tissue mast cells rather than blood basophils was based on light microscopical morphology and histochemistry. We have now studied the ultrastructure of these cells in mucosal biopsies taken before and during the birch pollen season. Intraepithelial cells with basophil or metachromatic granules were only observed in biopsies taken during the season. Some of these cells had the ultrastructural appearance of tissue mast cells, including cytoplasmic lipid droplets and a granular substructure composed of multilamellar arrays and scrolls, serving to distinguish human mast cells from blood basophils. The ultrastructural traits of the remaining cells were heterogeneous, some reminiscent of human blood basophils, others of globule leucocytes of other species, but entirely typical blood basophils could not be identified. The results thus support our previous suggestion that a migration of mucosal mast cells from the connective tissue stroma into the epithelium is part of the human allergic mucosal response. It cannot be determined whether the ultrastructural heterogeneity of these cells is the result of an adaptation to the intraepithelial environment of one single mast cell type or to the existence of an ultrastructurally distinct mucosal mast cell.

Basophils↗
PubMed1986

Dermal mast cells in mastocytosis: fixation, distribution and quantitation.

The mast cell distribution and number were studied in skin biopsies of 18 mastocytosis patients and 10 controls. The biopsies were stained for mast cells with toluidine blue at pH 0.5. The number in the upper dermis of lesional abdominal skin was at least twice as high as that of normal adjacent skin. Fixation in iso-osmotic 0.6% formaldehyde and 0.5% acetic acid, revealed more mast cells than conventional 4% formaldehyde fixation. Staining for 5 days, when compared to the normal for 30 min, increased the number of demonstrable mast cells just as did the change in fixation. Conventional formaldehyde fixation thus partially blocks the dye-binding of cutaneous mast cells, about 20% of the cells escaping detection. The degree of aldehyde blocking was similar in lesional and normal skin. A more pronounced blocking of dye-binding has been demonstrated previously in gut mucosal mast cells. Whether the blocking of dye-binding is an expression of heterogeneity in dermal mast cells remains to be determined.

Adolescent↗
PubMed1986

Proliferation and transepithelial migration of mucosal mast cells in interstitial cystitis.

The distribution and abundance of mast cells, as well as their fixation, staining and ultrastructural properties, were studied in the urinary bladders of 16 patients with interstitial cystitis (IC) and in 14 normal subjects. Tissues were fixed in both standard formaldehyde solution and a special fixative, IFAA, optimized for the preservation of mucosal mast cells. An expansion of two distinct mast cell populations was observed in IC. One of these, comprising formaldehyde-sensitive cells, was found only in the mucosa underlying lesions of IC. They were most numerous in the lamina propria but were also frequent in the epithelial layer as well as in the bladder washings, indicating a migratory capacity for these cells. The other mast cell population was visualized equally well irrespective of fixation and staining procedure. In control subjects, such cells were found both in the lamina propria and detrusor muscle, but not in the epithelium nor in bladder washings. In lesions of IC they were increased in the detrusor muscle only. Both types of mast cell contained granules with the highly characteristic lamellar arrays and scrolls, distinguishing human mast cell granules from those of blood basophils. The proliferation and intraepithelial distribution of mucosal mast cells are unusual findings, but prominent features of helminth responses and human mucosal allergic reactions. These findings thus suggest that the mucosal mast cell-IgE system may be involved in the pathogenesis and/or aetiology of IC.

Aged↗
PubMed1986

The bone marrow in urticaria pigmentosa and systemic mastocytosis. Cell composition and mast cell density in relation to urinary excretion of tele-methylimidazoleacetic acid.

The bone marrow sections from five normal subjects and 18 patients with mastocytosis were examined to establish criteria to distinguish urticaria pigmentosa from systemic mastocytosis. Nine patients had increased numbers of mast cells in bone marrow sections stained with a long toluidine blue staining technique specific for mast cells, whereas five patients exhibited increased numbers of mast cells on May-Grünwald-Giemsa-stained smears of bone marrow. A positive correlation between the number of mast cells in sections of the bone marrow and the urinary excretion of the main histamine metabolite tele-methylimidazoleacetic acid was found. In ten of the examined bone marrow specimens, focal lesions containing mast cells, lymphocytes, and eosinophils appeared. The presence of these focal lesions together with either an increased number of mast cells in bone marrow sections and/or increased urinary excretion of telemethylimidazoleacetic acid is considered diagnostic of systemic mastocytosis. No patient exhibited myeloproliferative condition or other major hematologic abnormality.

Adult↗
PubMed1985

Glycosaminoglycans in rat mucosal mast cells.

Rats were infected with the nematode Nippostrongylus brasiliensis, resulting in an approx. 5-fold increase in the number of mucosal mast cells and the histamine content of the intestinal (jejunum) wall. After injection of the infected animals with inorganic [35S]sulphate, a similar increase in the yield of labelled intestinal glycosaminoglycans was observed, compared with uninfected control rats. Autoradiography showed a highly selective labelling of the numerous mucosal mast cells and of the few connective-tissue mast cells in the subserosal region of the bowel. Analysis of the labelled polysaccharide from the infected animals showed that almost 60% of this material consisted of oversulphated galactosaminoglycan, whereas heparin-related polysaccharides accounted for only 13%. The galactosaminoglycan contained 4-monosulphated and 4,6-disulphated N-acetylgalactosamine residues in approx. 5:1 molar ratio, both being linked to D-glucuronic acid residues; the occurrence of L-iduronic acid units could not be excluded. No significant difference in structure was found between this polysaccharide and the corresponding component isolated from uninfected rats. It is concluded that the major polysaccharide produced by rat mucosal mast cells in vivo is an oversulphated galactosaminoglycan rather than heparin.

Animals↗
PubMed1985

Cellular repository for blood histamine in normal and nematode-infected rats.

Infections with the nematode N. brasiliensis is associated with a recruitment of intestinal mucosal mast cells (MMC) which increase greatly in numbers. We have studied histamine levels in the gut, whole blood and plasma in relation to MMC of the gut and blood cell morphology during the course of the infection in an attempt to clarify possible relations between circulating blood basophils and MMC. The results show a parallel increase in MMC numbers and histamine content of the gut, remaining high to day 20 after infection. Blood histamine increased from a control level of 30-40 ng/ml to a maximum of 200 ng/ml on day 12 to 14, but returned towards the control level already on day 16 after infection. There was a corresponding increase in plasma histamine to a maximum of 80 ng/ml. The total number of blood neutrophils increased during the early phase of the infection and there was a pronounced eosinophilia from day 10 to 16. No cells containing metachromatic granules were found in a screening comprised of 10,000 cells per specimen. During day 10 to 16 we found a number of coarsely granuled and vacuolated cells. The granules stained darkly by the Giemsa stain but not metachromatically with Toluidine Blue or with Alcian Blue at a low pH. We interpret this as an equivalent to the so-called toxic granulation occurring in human neutrophils. These cells may have been mistaken for basophils by previous investigators. The cellular repository for the high concentration of histamine in the blood is unknown. We suggest, as a working hypothesis, that it is contained in a circulating progenitor for MMC which has the ability to synthesize and, in a loosely bound state store, histamine, but which has not yet acquired the ability to assemble the specific metachromatic granules.

Animals↗
PubMed1985

A selective postcolumn o-phthalaldehyde-derivatization system for the determination of histamine in biological material by high-performance liquid chromatography.

Based on studies of the reaction between histamine and o-phthalaldehyde in alkaline solution, a method optimized for the determination of histamine in biological samples by means of HPLC and postcolumn o-phthalaldehyde derivatization has been developed. The method permits determination of histamine even at low-picomolar levels. By means of a valve, placed immediately after the column outlet, the eluent stream can be switched between the fluorimetric and an electrochemical detector system whereby electroactive biogenic amines may also be studied under the same chromatographic conditions.

Aldehydes↗
PubMed1985

Thymus dependence of connective tissue mast cells: a quantitative cytofluorometric study of the growth of peritoneal mast cells in normal and athymic rats.

The normal growth of peritoneal mast cells was studied in athymic and heterozygote rats over the period of 5-29 weeks of age. The total peritoneal mast cell mass and the mass of the granular components was calculated from mast cell numbers and their content of protein, heparin and 5-hydroxytryptamine. The growth process was analyzed by allometric log-log plots of mast cell quantities versus body weight and linear regressions. The mast cell growth in both groups of rats conformed to the allometric principle and was strictly proportional to the growth of the body as a whole. Two major differences between athymic and heterozygote rats were observed. The total peritoneal mast cell mass and the mass of its components was initially higher in the athymic rats, but the growth rate of the mast cells was lower. We suggest that the thymus may regulate the mast cells by an inhibitory factor acting on the bone marrow stem cell or circulating precursor level. The lower growth rate of the athymic rats may be due to the absence of a second, stimulatory thymic factor acting on the tissue precursor level, or to a tissue homeostatic mechanism triggered by the large initial mast cell mass and unrelated to the thymus.

Age Factors↗