Search results for "Histamine"
showing 10 items of 254 documents
Central activation by histamine-induced itch: analogies to pain processing: a correlational analysis of O-15 H2O positron emission tomography studies
2001
The aim of this study was to identify the functional cerebral network involved in the central processing of itch and to detect analogies and differences to previously identified cerebral activation patterns triggered by painful noxious stimuli. Repeated positron emission tomography regional cerebral blood flow (rCBF) measurements using O15-labeled water were performed in six healthy right-handed male subjects (mean age 32 +/- 2 years). Each subject underwent 12 sequential rCBF measurements. In all subjects a standardized skin prick test was performed on the right forearm 2 min before each rCBF measurement. For activation, histamine was applied in nine tests in logarithmically increasing con…
Perioperative nonspecific histamine release : a new classification by aetiological mechanisms and evaluation of their clinical relevance
1993
As a consequence of the performance of a randomized controlled clinical trial on perioperative histamine release and cardiovascular and respiratory disturbances, several types of increases in plasma histamine had to be distinguished instead of only two which existed at the beginning of the study: drug-induced allergic and pseudoallergic reactions. First of all, the new classification by aetiology (clinical epidemiology) was derived from a meta-analysis (secondary analysis) of the most recent literature. According to that histamine release in the perioperative period has several, different causes and is involved in several, different disease manifestations. A clear distinction (classificatio…
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…
Functional, biochemical and morphological studies on human bronchi after cryopreservation
1995
1. Human isolated bronchi have been investigated as fresh tissue or after storage (7 and 30 days) at -196 degrees C in foetal calf serum containing 1.8 M dimethyl sulphoxide. 2. After cryopreservation, the maximal contractile response to acetylcholine (3 mM) was reduced (approximately 25%) but the difference did not reach significance statistically. Maximal responses to other spasmogens tested (histamine, [Nle10]NKA(4-10), bradykinin, leukotriene D4, U46619, and KCl) did not differ between unfrozen and frozen/thawed tissues. The sensitivity of cryopreserved tissues to the constrictor agents tested was similar to that of fresh tissues. 3. The accumulation of inositol phosphates produced by a…
Bronchoconstriction induced by inhaled adenosine 5′-monophosphate in subjects with allergic rhinitis
2001
Adenosine and its related nucleotide, adenosine 5′-monophosphate (AMP) induce bronchoconstriction in asthmatics, probably caused by histamine release from airway mast cells. The objective of this study was to determine the effect of inhaled AMP on lung function in subjects with allergic rhinitis.A total of 52 adults (28 subjects with allergic rhinitis, 14 asthmatics and 10 healthy subjects) were challenged with increasing concentrations of AMP and methacholine. Airflow was assessed after each concentration and the response to each bronchoconstrictor agent was measured by the provocative concentration required to produce a 20% fall (PC20) in forced expired volume in one second (FEV1).All 14 …
Dose-Related Effect of Beclomethasone Dipropionate on Airway Responsiveness in Asthma
1990
The effects of twice daily inhaled beclomethasone dipropionate (BDP) at two dose levels (500 and 1,000 micrograms daily) on the airway responsiveness to inhaled histamine was evaluated by a randomized, single-blind, cross-over study in 10 patients with stable asthma. The 12-week study began with a 3-week run-in period of baseline treatment, which was continued unchanged throughout the study, and the two treatment periods were separated by a 3-week placebo period. Patients attended the laboratory every 3 weeks for spirometry and histamine inhalation tests to determine the provocative concentration of histamine causing a 20% fall in forced expiratory volume in 1 s (PC20 of FEV1). There was a …
Airway Responsiveness to Histamine in Patients Refractory to Repeated Exercise
1988
To investigate the mechanisms contributing to refractoriness in exercise-induced asthma (EIA), airway responsiveness to histamine was studied in eight asthmatic patients. Patients were included in the study on the basis of their refractory response to multiple exercise challenges. Incremental challenges with inhaled histamine were performed at rest and 40 minutes after single and paired exercise tests. The geometric mean histamine concentration required to produce a 20 percent fall in FEV1 (PC20) for the challenge after paired exercise test (4.34 mg/ml) was significantly higher (p greater than 0.001) than those for the challenges after a single exercise (1.05 mg/ml) and for the challenge at…
Early and late histamine release induced by albumin, hetastarch and polygeline: some unexpected findings.
2003
Objective: The perioperative use of colloidal plasma substitutes is still under discussion. We therefore conducted a prospective randomised study with three commonly used plasma substitutes to examine their histamine releasing effects in 21 volunteers. Material or subjects: 21 male volunteers were enrolled in this prospective, randomised, controlled clinical study. Endpoints were the incidence of early and late histamine release and the time course of the release kinetics. Normovolemic hemodilution technique was used with hydroxyethyl starch (n = 6), human albumin (n = 6) and polygeline (n = 9). Measurement and observation period was 240 min after the start of the plasma substitute infusion…
The Interaction of Buccal Mucosal Epithelial Cells with E. coli Bacteria Enhances the Intraepithelial Calcium Flux and the Release of Prostaglandin E…
1999
Mucosal epithelial cells contribute significantly to host defense mechanisms. Uroepithelial cells (UEC) from healthy donors suppress bacterial growth in vitro. Bacterial adherence to UEC has been shown to be a prerequisite. Similar results have been shown for buccal epithelial cells (BEC). The host response triggered by the host-parasite interaction seems to involve signal transduction and intracellular activation of second messengers. In this study the intraepithelial calcium flux was analyzed in individual BEC after bacterial contact. BEC were derived from scrapes of the buccal mucosa and labelled with fluo-3 (a calcium indicator). Thereafter the cells were analyzed immediately with a FAC…
Influence of vagus nerve stimulation on histamine-induced itching
2002
To investigate whether vagus nerve stimulation (VNS) reduces pruritus in humans.Recently, it has been shown that VNS has antinociceptive and antidepressant effects in humans.Eleven patients were investigated before (baseline) and during chronic VNS treatment. The experiments were performed at two different stimulation intensities: 2 to 5 days after implantation at a low stimulation intensity (mean intensity 0.7 +/- 0.2 mA, second session) and after 8 to 14 weeks of VNS therapy (mean intensity 1.4 +/- 0.3 mA, third session). Twelve healthy age- and sex-matched subjects were investigated using the same experimental protocol. Itch was induced by histamine-iontophoresis and quantified on a visu…