Search results for "Histamine Antagonist"

Histamine and spontaneously released mast cell granules affect the cell growth of human hepatocellular carcinoma cells

2007

The role of mast cells in tumor growth is still controversial. In this study we analyzed the effects of both histamine and pre-formed mediators spontaneously released by mast cells on the growth of two human hepatocellular carcinoma cell lines, HA22T/VGH and HuH-6, with different characteristics of differentiation, biological behavior and genetic defects. We showed that total mast cell releasate, exocytosed granules (granule remnants) and histamine reduced cell viability and proliferation in HuH-6 cells. In contrast, in HA22T/VGH cells granule remnants and histamine induced a weak but significant increase in cell growth. We showed that both cell lines expressed histamine receptors H(1) and …

Current therapeutical strategies for allergic rhinitis

2018

Allergic rhinitis is a common condition with increasing prevalence and is associated with several comorbid disorders such as bronchial asthma and atopic dermatitis. If allergen avoidance is not possible, allergen-specific immunotherapy is the only causal treatment option.This review focuses on current treatments and the future outlook for allergic rhinitis. Pharmacotherapy includes mast cell stabilizers, antihistamines, glucocorticosteroids (GCSs), leukotriene receptor antagonists, and nasal decongestants. Nasal GCSs are currently regarded as the most effective treatment and are considered first-line therapy together with non-sedating antihistamines. The new formulation MP29-02 combines the…

Clinical importance of eosinophil count in nasal fluid in patients with allergic and non-allergic rhinitis

2009

Eosinophil count in nasal fluid (ECNF) was used to differentiate nasal pathologies. Receiver Operating Characteristic (ROC) curve analysis and the area under the curve (AUC) were performed to evaluate the ECNF's accuracy in distinguishing allergic rhinitis (AR) from non-allergic rhinitis (NAR). We also evaluated the accuracy of ECNF in recognizing patients with mild and severe symptoms of rhinitis and patients with ineffective and effective clinical responses to antihistamines. 1,170 consecutive adult patients with a clinical history of rhinitis were studied. ECNF's median in AR was 6.0 and 2.0 in NAR and the best cut-off value was > 3.0, AUC = 0.75. ECNF's median in AR with mild nasal …

The effects of histamine on the isolated mouse uterus

2000

1. A study is made of the contractile and relaxant effects, and mechanism of action, of histamine on isolated uterus from mice treated with diethylstilboestrol, employing acetylcholine and adrenaline as contractile and relaxant standard agents. 2. Concentration-response curves for histamine agonists were obtained in the absence and presence of selective histaminergic blocking drugs (clemizole, ranitidine and thioperamide) and indomethacin. A number of experiments were carried out in uterus from reserpinised mice. Concentration-response curves for acetylcholine and adrenaline were also obtained in the absence and presence of their selective antagonist (atropine and propranolol). 3. In isolat…

Famotidine inhibits toll-like receptor 3-mediated inflammatory signaling in SARS-CoV-2 infection

2021

Apart from prevention using vaccinations, the management options for COVID-19 remain limited. In retrospective cohort studies, use of famotidine, a specific oral H2 receptor antagonist (antihistamine), has been associated with reduced risk of intubation and death in patients hospitalized with COVID-19. In a case series, nonhospitalized patients with COVID-19 experienced rapid symptom resolution after taking famotidine, but the molecular basis of these observations remains elusive. Here we show using biochemical, cellular, and functional assays that famotidine has no effect on viral replication or viral protease activity. However, famotidine can affect histamine-induced signaling processes i…

Differences and Similarities between Allergic and Nonallergic Rhinitis in a Large Sample of Adult Patients with Rhinitis Symptoms

2010

<i>Background:</i> Allergic rhinitis (AR) and nonallergic rhinitis (NAR) may present with different clinical and laboratory characteristics. <i>Methods:</i> A total of 1,511 consecutive patients, aged 18–81 years, diagnosed with rhinitis, 56% females and 44% males, underwent complete allergic evaluation including skin prick test, blood eosinophil counts, nasal eosinophil counts, peak nasal inspiratory flow (PNIF) measurement and evaluation of nasal symptoms using a visual analog scale (VAS). <i>Results:</i> A total of 1,107 patients (73%)had AR, whereas 404 (27%) had NAR. Patients with NAR were older and predominantly female. A higher nasal eosinophils co…

Synthesis and Characterization of New Bivalent Agents as Melatonin- and Histamine H3-Ligands

2014

Melatonin is an endogenous molecule involved in many pathophysiological processes. In addition to the control of circadian rhythms, its antioxidant and neuroprotective properties have been widely described. Thus far, different bivalent compounds composed by a melatonin molecule linked to another neuroprotective agent were synthesized and tested for their ability to block neurodegenerative processes in vitro and in vivo. To identify a novel class of potential neuroprotective compounds, we prepared a series of bivalent ligands, in which a prototypic melatonergic ligand is connected to an imidazole-based H3 receptor antagonist through a flexible linker. Four imidazolyl-alkyloxy-anilinoethylami…

Pharmacological investigation into the effects of histamine and histamine analogues on guinea-pig and rat colon in vitro.

1986

The effects of histamine and specific histamine agonists has been examined on isolated longitudinal colon strips of guinea-pig and rat. Histamine and 2-pyridyl-ethylamine but not 4 methylhistamine produced a concentration-related contractile response in the guinea-pig colon. The H1-antagonist clemizole antagonized competitively the effect of histamine but the H2-antagonist ranitidine did not modify the dose-response curve to histamine in the guinea-pig colon. Atropine, hexamethonium, prazosin and propranolol failed to modify the contractile response to histamine. Tone induced with KCl in guinea-pig isolated colon was not modified by histamine agonists even in tissues pretreated with clemizo…

Omalizumab is effective in symptomatic dermographism-results of a randomized placebo-controlled trial.

2016

Effect throughout the day of inhaled fenoterol on the bronchial responsiveness to histamine in asthmatic patients.

1987

The effect throughout the day of inhaled fenoterol on the bronchial responsiveness to inhaled histamine was evaluated in 8 asthmatic patients. The airway response to increasing concentration of histamine aerosol was assessed by measurement of forced expiratory volume in one second (FEV1). The provocative dose of histamine needed to cause a 20% fall in starting FEV1 was calculated from the cumulative log dose response curves. Histamine challenges were performed in duplicate, on separate days, after premedication with placebo or fenoterol given by metered dose inhalers in the morning and in the afternoon. The mean starting FEV1 in the morning and in the afternoon did not change significantly …