Leishmania (Viannia) braziliensis: human mast cell line activation induced by logarithmic and stationary promastigote derived-lysates

Herein we investigate the ability of live promastigotes and total lysate of Leishmania (Viannia) braziliensis, derived from parasites in the logarithmic (L-Lb) or stationary phase (S-Lb), to induce human mast cell line (HMC-1) activation. In comparison with medium-treated cells, a significant histamine release was observed in HMC-1 cultures stimulated with S-Lb. Lipophosphoglycan also induced histamine release by HMC-1 cells. In immunocytochemical assays, we found a marked staining for tryptase in medium-treated HMC-1 cells, however, stimulation with L-Lb or S-Lb caused a marked decrease in the color reaction as well as in the number of tryptase-positive cells. L-Lb and S-Lb induced an evident decrease in the intracellular expression of IL-4 but not IL-12. Live stationary promastigotes were able to induce high levels of IL-4 release in HMC-1 cultures. Furthermore, these cells released significant amounts of IL-12 when incubated with both types of live promastigotes. These results indicate that L. (V.) braziliensis promastigotes differ in their ability to induce direct human mast cells activation, according to the growth phase of the parasite. Furthermore, the release of pro-inflammatory mediators and cytokines could represent an important phenomenon that might favor the initial establishment of the infection.

Increasing Effect by Simultaneous Use of Levocabastine and Pemirolast on Experimental Allergic Conjunctivitis in Rats

The effect of the simultaneous use of 0.025% levocabastine hydrochloride eye drops (levocabastine) and 0.1% pemirolast potassium ophthalmic solution (pemirolast) on experimental allergic conjunctivitis in rats was investigated. Levocabastine and pemirolast significantly inhibited allergic conjunctivitis compared with the control group when separately administered. In addition, the simultaneous use of both drugs inhibited allergic conjunctivitis more potently than the original activity of levocabastine or pemirolast. Furthermore, the simultaneous use of levocabastine and pemirolast also significantly inhibited increased vascular permeability induced by antigen compared with levocabastine or pemirolast alone, respectively. Levocabastine and pemirolast inhibited histamine release from the rat conjunctiva in correlation with a decrease in histamine content in tears. When levocabastine and pemirolast were simultaneously applied to the eyes, histamine release from the conjunctiva was greater than for the original activities of both drugs. Similar to histamine release from the conjunctiva, the histamine content in tears induced by the simultaneous use of both drugs was significantly decreased compared with levocabastine and pemirolast alone, respectively. A potentiating effect induced by the simultaneous use of levocabastine and pemirolast may be attributable to the antihistaminic activity of levocabastine and histamine release inhibition by levocabastine and pemirolast.

Prostaglandin D2 Inhibits IgE-Mediated Scratching by Suppressing Histamine Release From Mast Cells

Effects of prostaglandin (PG) D(2), PGE(2), and PGI(2) on itch-associated scratching responses of mice and histamine release from the rat basophilic leukemia cell line RBL-2H3 were examined. PGD(2) and ketotifen but not PGE(2) and PGI(2) suppressed the scratching caused by ovalbumin injected into ovalbumin-sensitized mice. Ketotifen also suppressed compound 48/80-induced scratching but not PGD(2), PGE(2), and PGI(2). In vitro, PGD(2) suppressed the antigen-induced histamine release from RBL-2H3 cells, but PGE(2) and PGI(2) did not. These findings suggest that PGD(2) specifically suppressed IgE-mediated scratching by inhibiting IgE-mediated histamine release from mast cells.

Calcium-pH crosstalks in rat mast cells: modulation by transduction signals show non-essential role for calcium in alkaline-induced exocytosis

Alkalinization of cytosolic pH with ammonium chloride (NH4Cl) was reported to be a stimulus for mast cell degranulation. This paper studied the modulatory role of drugs that target protein kinase C (PKC), adenosine 3',5'-cyclic monophosphate (cAMP), tyrosine kinase (TyrK) and phosphatidylinositol 3-kinase (PI3K) on this effect. We used Go6976 (100 nM) and low concentrations of GF109203X (Gf) (50 nM) to inhibit calcium-dependent PKC isozymes. For calcium-independent isozymes, we used 500 nM Gf, and 10 microM rottlerin to specifically inhibit PKC delta, and chelerythrine as non-specific PKC inhibitor. Genistein (10 microM) and lavendustin A (1 microM) were used as unspecific TyrK inhibitors, and 10 nM wortmannin as a PI3K inhibitor. Chelerythrine and 50 nM Gf inhibit histamine release in the presence of external calcium. The inhibition caused by wortmannin was strictly internal calcium-dependent. cAMP-active drugs did not modify the response to NH4Cl. The effect of NH4Cl on histamine release was triggered by a transient elevation on cytosolic pH, which was simultaneous to an elevation on cytosolic calcium and followed by a probable Ca2+-H+ exchange after addition of external calcium. EGTA inhibit the response to suboptimal concentrations of NH4Cl, and BAPTA increased the effect of NH4Cl. There is a clear relationship between NH4Cl-mediated calcium release and histamine release, since those drugs that inhibit this release also inhibit NH4Cl-mediated histamine release; nevertheless, NH4Cl-mediated histamine release was possible in the absence of any calcium release, as shown with BAPTA. This data, in combination with the results with PKC inhibitors, suggest that calcium is not only unnecessary to trigger cell activation, but also that it may be a negative modulator of NH4Cl-mediated exocytosis.

In vitro evaluation of the potential role of sulfite radical in morphine-associated histamine release

BACKGROUND

Intravenous morphine use is associated with elevated histamine release leading to bronchoconstriction, edema and hemodynamic instability in some patients. This study evaluated the possibility that sulfite, which is present as a preservative in many morphine preparations, might contribute to histamine release in vitro.

RESULTS

The human mast cell line, HMC-1, was exposed to various morphine concentrations, in the absence of sulfite, under cell culture conditions. Clinically attained concentrations of morphine (0.018microg/ml and 0.45microg/ml) did not cause increased histamine release from mast cells. There was a significant increase in histamine release when the morphine concentration was increased by 1184-fold (668microg/ml morphine). Histamine release from mast cells exposed to morphine and/or sulfite required the presence of prostaglandin H synthetase. Histamine release in experiments using sulfite-containing morphine solutions was not statistically different from that observed in morphine-only solutions.

CONCLUSION

Sulfite in sulfite-containing morphine solutions, at concentrations seen clinically, is not responsible for histamine release in in vitro experiments of the human mast cell line, HMC-1. This does not preclude the fact that sulfite may lead to elevation of histamine levels in vivo.

Diazepam attenuates conditioned histamine release in guinea pigs

To clarify the possibility of pharmacological mediation on classical conditioning-associated asthmatic response, the effect of diazepam on an odor-induced conditioned histamine release was investigated in ovalbumin (OA)-sensitized guinea pigs, i.e. a model of bronchial asthma. The animals received conditioning sessions in which an antigen (OA) as the unconditioned stimulus and an odor (dimethylsulfide) as the conditioned stimulus (CS) were simultaneously inhaled. After the animals were intraperitoneally injected with saline or diazepam (2.5 or 5 mg/kg), they underwent exposure to the CS and blood collecting. This procedure was repeated three times in order that the animals would have each kind of injection. The animals injected with saline showed significantly higher levels of plasma histamine following the exposure to the CS as a conditioning effect compared with the baselines (P<0.05), whereas the group injected with diazepam (5 mg/kg) did not indicate such elevations. The suppressing effect of diazepam on the conditioned histamine release was also confirmed by a multiple regression analysis (5 mg/kg) and an analysis of covariance (2.5 and 5 mg/kg), even after adjustments for several factors regarding immunological sensitization and conditionability. The present study suggests that diazepam attenuates a conditioned histamine release.

Influence of histamine release on postoperative vomiting (POV) following gynaecological laparoscopic surgery

OBJECTIVE

The mechanisms leading to the high incidence of postoperative vomiting (POV) after gynaecological laparoscopic surgery are still unknown. The effectiveness of POV-prophylaxis using H1 + H2-receptor antagonists has been demonstrated, suggesting a role for histamine in the pathogenesis of POV. However, histamine levels were not measured in these studies. The aim of this study was to investigate the incidence of plasma histamine release and its association with POV after gynaecological laparoscopic surgery.

MATERIAL OR SUBJECTS

Twenty-two female patients, aged 20-56 y, classified ASA physical status I or II, undergoing elective gynaecological laparoscopic surgery were enrolled in the study. Blood samples for plasma histamine measurements were drawn at defined time points perioperatively. Emetic symptoms were recorded within the first 24 h after operation. A standardized balanced anaesthesia without any prophylactic antiemetic medication was applied. Formal causality analysis for histamine as a determinant for POV was performed.

RESULTS

The overall incidence of POV was 40.9% (9 out of 22 patients). Twelve out of 22 patients (54.5%) demonstrated a histamine release reaction during the whole observation period. Six out of 9 patients with POV (66.7%) had a histamine release. There was no difference in mean plasma histamine levels between POV-positive and POV-negative patients. The conditional probability for POV with histamine release was 6/12 = 0.5, in contrast to 3/10 = 0.3 for POV without histamine release.

CONCLUSIONS

A high incidence of plasma histamine release was demonstrated in most but not all patients with POV. The probability of POV with histamine release (0.5) was higher than without histamine release (0.3), thus histamine release was shown to be one of the contributory determinants for POV in this clinical study. Thus, patients at risk for POV may benefit from a H1 + H2-receptor antagonists prophylaxis alone or in combination with other antiemetic strategies.

Regulation of Con A ? dependent cytokine production from CD4+ and CD8+ T lymphocytes by autosecretion of histamine

OBJECTIVES

Previously we have shown that both CD4+ T cells and CD8+ T cells produce histamine when activated with Con A. The aim of this study was to examine whether cytokine production by these cells is regulated by autosecretion of histamine.

MATERIALS

CD4+ and CD8+ T cells were separated from spleen cells of C57BL/6 mice and mice lacking the H1 receptor (H1R) or H2R, using anti-CD4+- and anti-CD8+-coupled magnetic beads, respectively.

RESULTS

Depletion of the H1R resulted in decreases in the release of IL-2 and IL-10 from both CD4+ and CD8+ cells and increases in the release of IL-4 from CD4+ T cells and IFN-gamma from CD8+ cells. Mice lacking the H2R showed up-regulation of IFN-gamma secretion from CD8+ cells and of IL-4 from CD4+ and CD8+ T cells. Release of IL-2 and IL-10 from CD4+ as well as CD8+ cells was down-regulated in these mice. Both CD4+ and CD8+ T cell fractions synthesized histamine, which was enhanced in the H1R-deficient CD8+ T cells. Treatment of the cells with alpha-fluoromethyl-histidine, a specific inhibitor of HDC, or histaminase increased IFN-gamma from CD8+ cells, whereas it had no appreciable effect on IL-4 secretion from CD4+ cells.

CONCLUSION

These results suggest that cytokine production by CD4+ and CD8+ T lymphocytes is regulated by autosecretion of histamine.

Gastric secretion--from Pavlov's nervism to Popielski's histamine as direct secretagogue of oxyntic glands

Gastric acid and pepsin secretions result from the interplay of neurohormonal factors with stimulatory and inhibitory actions on oxyntic glands. At the turn of XIX century, the notion of nervism or entire neural control of digestive functions, developed by Pavlov prevailed. However, in the second part of XX century, hormonal control has been thought to play a major role in the mechanism of gastric secretion, especially gastrin, which was isolated and synthesized in 1964 by Gregory. Polish traces in gastroenterological history started with the discovery of histamine, a non-nervous and non-gastrin compound in oxyntic mucosa by L. Popielski in 1916, who found that this amine is the most potent and direct stimulant of gastric acid secretion. This histamine concept was supported by leading American gastroenterologists such as A.C. Ivy, championed later by C.F. Code, and clinically applied for testing gastric secretion by K. Kowalewski. Recently, it received a strong support from pharmacological research when J. Black designed H(2)-receptors antagonists, which were first discovered by M.I. Grossman and S.J. Konturek to inhibit not only histamine-, but also meal- and vagally-induced gastric acid secretion, thus reinforcing the notion of the crucial significance of histamine in the control of gastric secretion as the final common chemostimulator. In conclusion, Polish traces appear to be substantial in gastric history due: 1) to discovery by Popielski that histamine is a major, direct stimulus of gastric secretion; 2) to clinical application of this agent by Kowalewski in testing maximal gastric secretory activity; and 3) to clinical use of histamine H(2)-antagonists in control of gastric acid secretion and treatment of peptic ulcers.

Characterization and function of the multifaceted peripheral blood basophil

Basophils are derived from metachromatic hematopoietic precursor cells of myeloid origin. The basophilic granulocyte differentiates and matures in the bone marrow, circulates in the peripheral blood, and upon proper stimulation, migrates into the tissues. Peripheral blood basophils act as chief effector cells of the allergic response and as purveyors of various allergy-associated mediators. Under appropriate conditions, basophils can be induced to release their mediators into the extracellular space of tissues or blood of the host organism. The plasma membrane of basophils contains receptors for immunoglobulin E (IgE) homocytotropic antibody which exhibits high affinity for these granulocytes and their Fc epsilon receptors. IgE cytophilic antibody binds antigen at its Fab portion. When bound to the basophil plasma membrane, the antigen-antibody complex undergoes multivalent interactions, which create crosslinking of the Fc epsilon receptors on the basophil plasma membrane. This receptor cross-linking results in basophil degranulation and subsequent release of its pharmacologically active substances. The basophil exhibits considerable heterogeneity and is characterized as Type I, II, III, IV, V and VI based upon granule content and time of antigen stimulation. Evidence is presented showing the role of the basophil in hyperplasia, hypersensitivity, parasitic infections and other diseases.

Direct effects of proton pump inhibitors on histamine release from rat enterochromaffin-like cells

Enterochromaffin-like (ECL) cells play a central role in the regulation of gastric acid secretion. Previous studies have shown that proton pump inhibitors accelerate histamine release from ECL cells through the effects of gastrin. However, direct effects of proton pump inhibitors on ECL cells have not been demonstrated to date because the indirect effects of gastrin are difficult to suppress. We investigated the direct effects of proton pump inhibitors medication on ECL cells using an elutriation system. ECL cells were stimulated with gastrin or rabeprazole, and histamine release from ECL cells was measured. Rabeprazole increased histamine release through a pathway that differed from that of gastrin. The histamine increase was likely due to an acceleration of vesicular monoamine transporter 2 (VMAT2). Rabeprazole increased histamine release from ECL cells directly via VMAT2, but did not affect the total amount of histamine in the cells. The results suggest that patients receiving proton pump inhibitors for extended periods must be monitored extensively because gastric tumor proliferation may be promoted by increased histamine release from ECL cells.

Acute stress modulates the histamine content of mast cells in the gastrointestinal tract through interleukin-1 and corticotropin-releasing factor release in rats

Stress results in activation of the hypothalamic pituitary adrenal axis and affects illnesses such as neuroinflammatory syndrome. In vivo acute stress (restraint stress) induces gastrointestinal function disturbances through colonic mast cell activation. This study investigated the effect of acute stress in histamine content of colonic mast cells, and the central role of interleukin-1 (IL-1) and corticotropin-releasing factor (CRF) in this effect. After a restraint stress session colonic segments were isolated and submitted to three protocols: (i) determination of histamine levels by radioimmunoassay (RIA) after incubation with 48/80 compound, (ii) evaluation by histology of mucosal mast cell (MMC) number and (iii) determination of histamine immunoreactivity of MMC. These procedures were conducted (1) in sham or stressed rats, (2) in stressed rats previously treated with intracerebroventricular (I.C.V.) IL-1ra or alpha-helical CRF9-41, (3) in naive rats pretreated with I.C.V. rhIL-1beta or CRF and (4) in rats treated with central IL-1beta and CRF plus alpha-helical CRF and IL-1ra, respectively (cross-antagonism reaction). Acute stress increases histamine content in colonic mast cells, without degranulation. I.C.V. pretreatment with IL-1ra or alpha-helical CRF9-41 blocked stress-induced mast cell histamine content increase. Both I.C.V. rhIL-1beta and CRF injections reproduced the stress-linked changes. I.C.V. treatment with CRF antagonist blocked I.C.V. rhIL-1beta-induced mast cell histamine content increase, whereas central IL-1ra did not affect stress events induced by I.C.V. CRF administration. These results suggest that in rats acute stress increases colonic mast cell histamine content. This effect is mediated by the release in cascade in the brain first of IL-1 and secondly of CRF.

Co-localization of histamine and dopamine-beta-hydroxylase in sympathetic ganglion and release of histamine from cardiac sympathetic terminals of guinea-pig

1. The aim of this study was to investigate the co-localization of histamine and dopamine-beta-hydroxylase in the superior cervical ganglion of guinea-pig and release of histamine from cardiac sympathetic terminals in guinea-pig isolated atrium. 2. Histidine decarboxylase (a histamine-synthesizing enzyme) mRNA signals were detected in the neurones of superior cervical ganglion of guinea-pig by in situ hybridization. The results of double-labelled immunofluorescence further confirmed the co-localization of histamine and dopamine-beta-hydroxylase in the large principle neurons and small intensely fluorescent cells in the superior cervical ganglion. The immunoreactivities of both histamine and dopamine-beta-hydroxylase were significantly attenuated after 6-hydroxydopamine-induced lesion of sympathetic nerves. 3. The refractory electrical field stimulation caused the release of histamine from cardiac sympathetic terminals of guinea-pig isolated atria (112.14 +/- 40.34 ng x ml(-1)), which was significantly attenuated to 35 +/- 15.57 ng x ml(-1) by reserpine pretreatment. Following administering compound 48/80, a mast cell degranulator, electrical field stimulation induced a dramatic increase of endogenous histamine release from isolated atria (303.57 +/-72.93 ng x ml(-1)). When compound 48/80 was added to the reserpine-treated atria, the release of histamine induced by field stimulation was decreased to 207.14 +/- 76.39 ng x ml(-1). 4 These results provide novel evidence that histamine co-exists with noradrenaline in sympathetic nerves and might act as a neurotransmitter to modulate sympathetic neurotransmission.

Submucosal microinfusion of endothelin and adrenaline mobilizes ECL-cell histamine in rat stomach, and causes mucosal damage: a microdialysis study

Rat stomach ECL cells release histamine in response to gastrin. Submucosal microinfusion of endothelin or adrenaline, known to cause vasoconstriction and gastric lesions, mobilized striking amounts of histamine. While the histamine response to gastrin is sustainable for hours, that to endothelin and adrenaline was characteristically short-lasting (1-2 h). The aims of this study were to identify the cellular source of histamine mobilized by endothelin and adrenaline, and examine the differences between the histamine-mobilizing effects of gastrin, and of endothelin and adrenaline. Endothelin, adrenaline or gastrin were administered by submucosal microinfusion. Gastric histamine mobilization was monitored by microdialysis. Local pretreatment with the H1-receptor antagonist mepyramine and the H2-receptor antagonist ranitidine did not prevent endothelin- or adrenaline-induced mucosal damage. Submucosal microinfusion of histamine did not cause damage. Acid blockade by ranitidine or omeprazole prevented the damage, suggesting that acid back diffusion contributes. Gastrin raised histidine decarboxylase (HDC) activity close to the probe, without affecting the histamine concentration. Endothelin and adrenaline lowered histamine by 50-70%, without activating HDC. Histamine mobilization declined upon repeated administration. Endothelin reduced the number of histamine-immunoreactive ECL cells locally, and reduced the number of secretory vesicles. Thus, unlike gastrin, endothelin (and adrenaline) is capable of exhausting ECL-cell histamine. Microinfusion of alpha-fluoromethylhistidine (known to deplete ECL cells but not mast cells of histamine) reduced the histamine-mobilizing effect of endothelin by 80%, while 1-week pretreatment with omeprazole enhanced it, supporting the involvement of ECL cells. Somatostatin or the prostanoid misoprostol inhibited gastrin-, but not endothelin-stimulated histamine release, suggesting that endothelin and gastrin mobilize histamine via different mechanisms. While gastrin effectively mobilized histamine from ECL cells in primary culture, endothelin had no effect, and adrenaline, a modest effect. Hence, the striking effects of endothelin and adrenaline on ECL cells in situ are probably indirect, possibly a consequence of ischemia.

The American dog tick, Dermacentor variabilis, encodes a functional histamine release factor homolog

We have identified a functional Dermacentor variabilis histamine release factor (DVHRF) homolog and shown that it is a secreted tick saliva protein. The 945 base pair (bp) full-length DVHRF cDNA has a 522 bp open reading frame that encodes a 20 kDa (173 amino acid) polypeptide. Sequence analysis showed that the two HRF signature amino acid sequences were conserved in DVHRF, indicating close structural similarity between DVHRF and other characterized HRF homologs. Northern and Western blotting analyses of partially fed and unfed ticks indicates that neither DVHRF transcriptional nor translational regulation were influenced by tick feeding activity. Like its counterparts from the mammalian system, tick DVHRF is expressed in various tissues, as assessed by both Northern and Western blotting analyses. Furthermore, an Escherichia coli-expressed recombinant DVHRF induced histamine secretion from a rat basophilic leukemic cell line in a dose-dependent manner. Extensive experimental evidence has shown that high levels of histamine at tick attachment sites impede the biological success of feeding ticks and, in response, ticks secrete histamine-binding proteins to minimize the adverse effects of histamine. Our results suggest the existence of a tick-derived multifaceted control mechanism for levels of histamine at tick feeding sites.

Biologic activity of RANTES in apheresis PLT concentrates and its involvement in nonhemolytic transfusion reactions

BACKGROUND

RANTES, one of the PLT-derived biologic response modifiers, accumulates in PLT concentrates (PCs) during storage and may play a causative role in nonhemolytic transfusion reactions (NHTRs) after PC transfusion.

STUDY DESIGN AND METHODS

To investigate the association of RANTES with NHTRs, the biologic activity of RANTES in the supernatant of stored PC at the intravascular concentration expected after PC transfusion was assessed by examining chemotaxis and histamine release in human basophils. In addition, the levels of RANTES in PCs involved in NHTRs were compared with those in PCs causing no transfusion reactions.

RESULTS

The supernatant of PC diluted to contain 1 nM RANTES significantly increased the migration of and release of histamine from basophils. Neutralizing antibody to RANTES suppressed the PC-triggered migration, but not histamine release. The levels of RANTES in PCs involved in NHTRs after PC transfusion were comparable to those in PCs that did not cause any transfusion reactions.

CONCLUSION

RANTES that accumulated in PCs during storage was biologically active in a basophil chemotaxis assay at the intravascular concentration expected after PC transfusion. However, the NHTRs after PC transfusion were not simply related to the RANTES level in PCs.

Activation of murine lung mast cells by the adenosine A3 receptor

Adenosine has been implicated to play a role in asthma in part through its ability to influence mediator release from mast cells. Most physiological roles of adenosine are mediated through adenosine receptors; however, the mechanisms by which adenosine influences mediator release from lung mast cells are not understood. We established primary murine lung mast cell cultures and used real-time RT-PCR and immunofluorescence to demonstrate that the A(2A), A(2B), and A(3) adenosine receptors are expressed on murine lung mast cells. Studies using selective adenosine receptor agonists and antagonists suggested that activation of A(3) receptors could induce mast cell histamine release in association with increases in intracellular Ca(2+) that were mediated through G(i) and phosphoinositide 3-kinase signaling pathways. The function of A(3) receptors in vivo was tested by exposing mice to the A(3) receptor agonist, IB-MECA. Nebulized IB-MECA directly induced lung mast cell degranulation in wild-type mice while having no effect in A(3) receptor knockout mice. Furthermore, studies using adenosine deaminase knockout mice suggested that elevated endogenous adenosine induced lung mast cell degranulation by engaging A(3) receptors. These results demonstrate that the A(3) adenosine receptor plays an important role in adenosine-mediated murine lung mast cell degranulation.

Stimulatory effects of nitric oxide donors on histamine release in isolated rat gastric mucosal cells

We previously reported stimulatory effects of endogenous and exogenous nitric oxide (NO) on gastric acid secretion. In the present study, we investigated effects of NO donors on release of histamine, which is related to acid secretion, in isolated rat gastric mucosal cells. NO donors such as (+/-)-(E)-4-methyl-2-[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexanamide (NOR 1) and sodium nitroprusside significantly augmented the histamine release. It was inhibited by 2-(4-carboxyphenyl)-4,4,5,5,-tetramethylimidazoline-1-oxyl-3-amide (carboxy-PTIO), a NO scavenger, and 6-(phenylamino)-5,8-quinolinedione (LY83583), a soluble guanylate cyclase inhibitor. Dibutyryl cyclic GMP also stimulated histamine release. These results suggest that NO donors act on cyclic GMP pathway in isolated gastric mucosal cells, resulting in facilitation of histamine release. NO may stimulate gastric acid secretion through histamine release from the histamine-containing cells, possibly enterochromaffin-like cells.

[Management of psychologic factors in chronic urticaria. When and how?]

INTRODUCTION

Chronic idiopathic urticaria is a frequent disease witch treatment is often disappointing. Psychological factors seem to be frequently associated to it. In what cases consider psychological treatment? And according to what modalities?

METHOD

Review of the literature in search of articles in both French and English concerning psychological factors associated to chronic urticaria, either as responsible factors, or as aggravating factors, or as a consequence of the urticaria, with the study of the impact on the quality of life. We also studied articles analyzing various types of psychology-targeted treatments. We use a serie of keywords on following data banks: Medline (1970-2002), Embase, Pascal and Cochrane Library (period 1995-2002).

RESULTS

Very few controlled studies were published.: Various studies are found reporting an association between stress, anxiety or depressive symptomatology and CIU, but none can assert a causality. Three controlled opened studies show significantly more anxiety and\or depression in the chronic urticaria patients. Three studies analyze the psychopathological personalities of the patients with urticaria. Two studies focus specifically on the impact of the CIU on the quality of life. Various psychotropic drugs (mainly tricyclic antidepressants) have been tested, mostly because of their anti-H1 activity. There is no study on psychological support, psychotherapies, behavioral therapies, technique of biofeedback and group therapies. A particular attention is focused to hypnosis and relaxation techniques because of the improvement of the urticarial wheals reported in studies of cutaneous ability to react in subcutaneous injections of histamine.

CONCLUSION

A complementary psychological treatment of patients suffering from CIU seems necessary, because of the high frequency of psychological symptoms. Published studies concern essentially the prescription of psychotropic drugs and the use of therapies with suggestion or relaxation under hypnosis. Prospective studies on the impact of an adapted psychological treatment on the CIU evolution are not available.

Effects of methyl p-hydroxybenzoate (methyl paraben) on Ca2+ concentration and histamine release in rat peritoneal mast cells

1 Mechanisms of methyl p-hydroxybenzoate (methyl paraben) action in allergic reactions were investigated by measuring the intracellular Ca(2+) concentration ([Ca(2+)](i)) and histamine release in rat peritoneal mast cells (RPMCs). 2 In the presence or absence of extracellular Ca(2+), methyl paraben (0.1-10 mM) increased [Ca(2+)](i), in a concentration-dependent manner. Under both the conditions, methyl paraben alone did not evoke histamine release. 3 In RPMCs pretreated with a protein kinase C (PKC) activator (phorbol 12-myristate 13-acetate (PMA) 3 and 10 nM), methyl paraben (0.3-3 mM) induced histamine release. However, a high concentration (10 mM) of the agent did not increase the histamine release. 4 U73122 (0.1 and 0.5 micro M), an inhibitor of phospholipase C (PLC), significantly inhibited the methyl paraben-induced histamine release in PMA-pretreated RPMCs. U73343 (0.5 micro M), an inactive analogue of U73122, did not inhibit the histamine release caused by methyl paraben. 5 In Ca(2+)-free solution, PLC inhibitors (U73122 0.1 and 0.5 micro M, D609 1-10 micro M) inhibited the methyl paraben-induced increase in [Ca(2+)](i), whereas U73343 (0.5 micro M) did not. 6 Xestospongin C (2-20 micro M) and 2 aminoethoxydiphenyl borate (30 and 100 micro M), blockers of the inositol 1,4,5-trisphosphate (IP(3)) receptor, inhibited the methyl paraben-induced increase in [Ca(2+)](i) in Ca(2+)-free solution. 7 In conclusion, methyl paraben causes an increase in [Ca(2+)](i), which may be due to release of Ca(2+) from storage sites by IP(3) via activation of PLC in RPMCs. In addition, methyl paraben possibly has some inhibitory effects on histamine release via unknown mechanisms.

Gastric atrial natriuretic peptide regulates endocrine secretion in antrum and fundus of human and rat stomach

Atrial natriuretic peptide (ANP) is present in gastric mucosa and preferentially binds to two subtypes of natriuretic peptide receptors (NPR), NPR-A and NPR-C. The present study examines the role of endogenous ANP in regulating endocrine secretion in rat and human stomachs. NPR-A protein expression and transcripts were identified in rat antral and fundic mucosa by Western blot and RT-PCR. In superfused rat and human antral and fundic segments, ANP (0.1 pM to 0.1 microM) caused a concentration-dependent increase in somatostatin secretion. In antrum, this was accompanied by a decrease in gastrin, and in fundus, this was accompanied by a decrease in histamine secretion. Changes in gastrin and histamine secretion reflected changes in somatostatin secretion and were abolished by somatostatin antibody. The NPR-A receptor antagonist anantin 1) inhibited basal somatostatin secretion and 2) abolished the somatostatin, gastrin, and histamine responses to ANP. We conclude that endogenous ANP, acting via the NPR-A receptor, stimulates somatostatin secretion from both antrum and fundus of rat and human stomach. Stimulation of somatostatin secretion is coupled to inhibition of gastrin secretion in the antrum and inhibition of histamine secretion in the fundus.

Calcineurin antagonists differentially affect mediator secretion, p38 mitogen-activated protein kinase and extracellular signal-regulated kinases from immunologically activated human basophils

BACKGROUND

Basophils participate in allergic diseases by invading affected tissues and secreting histamine, leukotriene (LT)C4, IL-4 and IL-13 following FcepsilonRI cross-linking. A reduction of basophil mediator production is therefore of considerable therapeutical interest. Macrolactam derivatives, which inhibit calcineurin activation, may be candidates for antiallergic therapy as they reduce both symptoms of inflammatory skin disease in animal models and mast cell degranulation.

OBJECTIVE

To investigate the effects of the calcineurin antagonists ascomycin and cyclosporin A on IgE-dependent mediator release from human basophils.

METHODS

Basophils were purified by Ficoll density centrifugation, elutriation and negative selection. Histamine release was measured spectrofluorometrically; LTC4, IL-4 and IL-13 secretions were assayed by enzyme-linked immunosorbent assay (ELISA). Lysed cells were subjected to Western blotting using specific antibodies to phospho-p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK)-1 and -2.

RESULTS

Ascomycin (0.01 nm to 1 micro m) and cyclosporin A (0.1 nm to 10 micro m) strikingly inhibited (maximally 100%) anti-IgE-induced histamine and cytokine release from basophils, and these actions were unaffected by IL-3 priming. Ascomycin, however, was less potent at blocking LTC4 secretion, whereas cyclosporin A was unable to block production of this mediator. In immunoblotting studies, ascomycin and cyclosporin A reduced IgE-dependent p38 MAPK activation but were less potent at reducing ERK phosphorylation in basophils.

CONCLUSION

Calcineurin antagonists like ascomycin and cyclosporin A block IgE-dependent basophil degranulation and cytokine synthesis. Calcineurin may target p38 MAPK activation, but seems to have less activity on ERK phosphorylation. This is paralleled by a reduced or even absent effect of calcineurin antagonists on eicosanoid production.