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EN
Histamine is a physiological mediator which exerts both effector and regulatory functions through its receptors on various cells. The aim of the study was to investigate changes in histamine receptor expression on peripheral blood lymphocytes affected by stimulation with both specific and nonspecific stimuli. Lymphocytes were obtained from both healthy and allergic subjects. Cells were incubated with various allergens (mixed grass pollen, Lolium perenne, Dermatophagoides pteronyssinus 1, bee venom, phospholipase A2) and nonspecific (fMLP, PMA/ionomycin, LPS) stimuli. The percentage of histamine-binding cells was determined with a fluorescence microscope after incubation with histamine-fluorescein. In control subjects histamine binding after stimulation with allergens was not significantly changed. In contrast, in allergic subjects stimulation with specific allergens resulted in significantly increased histamine binding. Nonspecific stimulation caused increased histamine binding to lymphocytes in both allergic subjects and healthy controls. We conclude that specific and nonspecific activation of lymphocytes is associated with increased expression of histamine receptors.
EN
Intruction: Numerous pathophysiological conditions change during 24-hour periods. Histamine, the main mediator in allergic reactions, exerts a multiplicity of pathophysiological actions through binding to specific receptors on effector cells. Nocturnal exacerbation of symptoms occurs in many atopic diseases in which histamine is an important mediator. Nocturnal wheezing is a very common symptom of asthma. The aim of this study was to determine whether the binding of (fluorescein-labeled) histamine to cells participating in allergic-inflammatory processes (lymphocytes, neutrophils) and skin reactivity to histamine undergo circadian changes and to compare these phenomena in atopic asthmatic and healthy subjects. Materials and Methods: Blood samples were collected at 8 am, 2 pm, 8 pm, 2 am, and 8 am the next day. Histamine skin-prick tests were performed at the same times. Results: It was found that skin reactivity to histamine (wheal, erythema) in healthy subjects underwent significant circadian changes with acrophase at 8 am (wheal) or 8 pm (erythema), the lowest values being at night (2 am, p=0.017), in contrast to atopics, in whom the highest reactivity was found at night (2 am, p=0.002). Significant differences in the binding of fluorescein-labeled histamine between day (8 am?2 pm) and night (2 am) were observed for lymphocytes (p=0.006) and neutrophils (p=0.018). Conclusions: In the asthmatic group these changes were not significant. Circadian changes in both the binding of histamine by effector cells and skin reactivity to histamine were different in healthy and asthmatic subjects, and this may play a role in the pathomechanism, course, and chronopharmacotherapy of atopic diseases.
EN
The study was undertaken to examine the effect of isoprinosine treatment on in vitro histamine release from peritoneal mast cells. The experiments were done on mice which received isoprinosine orally, at a dose of 50 or 100 mg per kilogram of body weight per day, in divided doses, every 8 hours, for a period of 1 - 9 days. After isoprinosine treatment, there was a significant decrease of in vitro Con A-induced histamine release from mast cells. This inhibitory effect was observed in both tested groups. In the second experiment, with mice sensitized with egg albumin, the treatment with isoprinosine gave also a significant inhibition of anaphylactic histamine release from mast cells, as compared with that of control without isoprinosine treatment. Results of both experiments suggested that isoprinosine may have some inhibitory effect on mast cell activation.
EN
Human mast cells were obtained from adenoids and mesentery by enzymatic dispersion of the tissues with the enzyme collagenase. The digestion of the tissues resulted in a cell suspension which contained 1 - 2% mast cells. 37,3% (adenoids) and 33,4% (mesentery) of total histamine initially present in the tissues was recovered in the dispersed cell suspensions. More than 90% of the cells were viable. The adenoidal mast cells could be sensitized passively in vitro with homologous reaginic serum and released histamine after challenge with specific antigen. Both populations of mast cells were sensitive to the action of anti-human IgE: the reversed anaphylaxis with anti-IgE was higher in mesenteric mast cells. Both examined mast cell populations were sensitive to the challenge with polymyxin B, concanavalin A and ionophore A23187, however, histamine release was only up to 10% and 20% for adenoidal and mesenteric cells, respectively. Only mesenteric mast cells responded to the action of compound 48/80. Histamine release induced by polymyxin B, was rapid (maximal release within 5 min), maximal in the presence of 3 mM extracellular calcium ions (but also occured in the absence of the cation).
EN
The purpose of the present study was: (1) to demonstrate immunocytochemically the localization of histamine in the wall of four chicken oviductal parts, i. e. infundibulum, magnum, isthmus, and shell gland, (2) to identify the presence of mast cells in chicken oviduct, and (3) to determine histamine concentration in oviductal tissue by the spectrofluorometric method. Experiments were carried out on Isa Brown laying hens decapitated just after oviposition. The specific immuno-reactivity for histamine and the presence of mast cells were found in the wall of all the examined oviductal parts. The immuno-reactive histamine was localized in epithelium, tubular glands, connective tissue layer, circular and longitudinal muscles, and endothelium and muscles of blood vessels. The intensity of immuno-positive reaction was as follows: infundibulum > shell gland > magnum = isthmus and correlated with quantitatively determined histamine level and tissue density of mast cells. It is suggested that mast cells are the main source of histamine in the chicken oviduct.
EN
The levels of histamine (HA) and tele-methylhistamine (t-MeHA) in the pineal gland of chick were measured by RIA and two time points, i.e. at the end of the light (L) phase and in the middle of the dark (D) phase of 12h :12h L:D cycle.The chick pineal gland showed high HA levels.The t-MeHA content of chick pineal gland was about 20-times lower than HA levelAn aminoacid precursor of HA, L-histidine given to chicks during L or D significantly increased both HA and t-MeHA content of pineal gland.The L-histidine-evoked elevations in HA level were 2-4 times higher than changes in t-MeHA content.Enzymatic study showed the presence of chick pineal gland of a moderate activity of L-histidine decarboxylase, and well expressed activity of HA-methyltransferase, HA synthetizing and inactivating enzyme, respectively, which suggest that both HA and t-MeHA may be produced within the gland.It is suggested that the metabolic dynamics of the pineal HA may be higher during lighthours than darkhours of the daily light:dark illumination cycle.
EN
Nasal provocation tests with histamine and methacholine were carried out in 25 healthy men on an effort to assess the dynamic changes of albumin, total IgA, secretory IgA and lactoferrin concentrations in the nasal secretion. The trials were performed with 0.5, 1, and 4 mg of histamine and 8, 16, 32 mg of methacholine. Each dose of histamine or methacholine was sprayed into a nose every second day, and with two days interval between two provocating agents. The nasal secretions were collected after saline spraying only forming baseline group and after 3, 10 and 15 minutes of the challenge agent administration. The baseline levels presented the following values: for albumin 257? 230 mug/ml, secretory IgA 608 ? 379 mug/ml, total IgA 1025 ? 423 mug/ml, and lactoferrin 213 ? 156 mug/ml. The increase of albumin level after nasal provocation, particularly significant after histamine administration (to 3713 ? 2311 mug/ml), indicates the incessant protein plasma leaking from the blood circulation to the nasal secretion. After administration of both provocating agents there was the significant gradual decrease of secretory IgA level, even below the baseline value. After the 2nd and the 3rd doses of methacholine and histamine spraying the concentration of secretory IgA decreased 2-3 times and was found to be 200-300 mug/ml, respectively. Also, lactoferrin concentration values decreased gradually after the 2nd and 3rd doses of methacholine and histamine to level close the baseline value. These observations suggest time and dose dependent, a non-specific dysfunction of local immunity response after nasal provocations.
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