Search results for "harm"
showing 10 items of 13866 documents
ROLIPRAM INHIBITS PAF-INDUCED AIRWAY MICROVASCULAR LEAKAGE IN GUINEA-PIG - A COMPARISON WITH MILRINONE AND THEOPHYLLINE
1992
The effects of 3 phosphodiesterase (PDE) inhibitors, rolipram (PDE IV), milrinone (PDE III) and theophylline (non-selective) on PAF (50 ng kg-1; iv)-induced airway vascular leakage have been evaluated in guinea-pigs. Rolipram (3-300 micrograms kg-1; iv) reduced the increase in permeability induced by PAF at all airway levels whereas milrinone (10-1000 micrograms kg-1; iv) and theophylline (30 mg kg-1; iv) were without effects. The anti-leakage activity of rolipram may be of therapeutic value in asthma.
Epithelium-derived inhibition of [3H]acetylcholine release from the isolated guinea-pig trachea
1990
To investigate presynaptic, regulatory mechanisms on parasympathetic nerve fibres innervating the airways, the release of newly-synthesized [3H]acetylcholine from the isolated trachea was studied. Reverse phase HPLC followed by liquid scintillation spectrometry was used to separate and quantify the radioactive compounds choline, phosphorylcholine and acetylcholine in the incubation medium and the tissue. During the incubation of the tracheae with [3H]choline a significant synthesis of [3H]acetylcholine (35,000 dpm/preparation) and [3H]phosphorylcholine (500,000 dpm/preparation) occurred. In epithelium-deficient tracheae the formation of [3H]phosphorylcholine was enhanced, whereas the conten…
Physical Activity in Polluted Air—Net Benefit or Harm to Cardiovascular Health? A Comprehensive Review
2021
Both exposure to higher levels of polluted air and physical inactivity are crucial risk factors for the development and progression of major noncommunicable diseases and, in particular, of cardiovascular disease. In this context, the World Health Organization estimated 4.2 and 3.2 million global deaths per year in response to ambient air pollution and insufficient physical activity, respectively. While regular physical activity is well known to improve general health, it may also increase the uptake and deposit of air pollutants in the lungs/airways and circulation, due to increased breathing frequency and minute ventilation, thus increasing the risk of cardiovascular disease. Thus, determi…
Effects of dopamine in isolated rat colon strips.
2005
The aim of the present work is to investigate the effects of dopamine on isolated rat colon strips, and whether dopamine receptors are involved in these effects. Experiments on spontaneous motility and under potassium contraction were performed with dopamine and isoprenaline, both in the absence and presence of antagonists (distal colon strips, isotonic recording, Tyrode solution, 31 °C, 1 g of resting tension). At higher concentration (10–4mol/L), dopamine abolished spontaneous motility of the rat colon and this effect was not modified by antagonists. In isolated rat colon strips that were depolarized with potassium, dopamine produced concentration-dependent relaxation, without significant…
Substance P inactivation by transglutaminase in vitro.
1992
Gamma(glutamyl5)spermine derivative of substance P (Spm-SP) was synthesized in vitro in the presence of purified guinea pig liver transglutaminase and Ca2+. The spermine adduct of the neuropeptide was purified by HPLC on a reversed-phase column and characterized by fast atom bombardment mass spectrometry. The biological activities of Spm-SP were tested by assaying, in comparison with substance P, its ability to induce both the contractions of smooth muscle in vitro and the edema formation in vivo. Spm-SP was shown not to elicit contractile responses in the isolated rat stomach strip and duodenum and not to antagonize the spasmogenic effect evoked by the native neuropeptide. Furthermore, Spm…
Inter-relationship between platelet-derived microparticles and oxidative stress in patients with venous thromboembolism
2020
Background: Hypercoagulative conditions play a key role in venous thromboembolism (VTE). Inflammation is currently linked to VTE, but the potential role of circulating microparticles and oxidative stress (OxS) must be elucidated. The aim of this study was to evaluate platelet-derived microparticles and surrogate OxS biomarkers in patients diagnosed with VTE through a case&ndash
Release of acetylcholine from murine embryonic stem cells: Effect of nicotinic and muscarinic receptors and blockade of organic cation transporter
2012
The non-neuronal cholinergic system is widely expressed in nature. The present experiments were performed to characterize the non-neuronal cholinergic system in murine embryonic stem cells (CGR8 cell line).CGR8 cells were cultured in gelatinized flasks with Glasgow's buffered minimal essential medium (Gibco, Germany). Acetylcholine was measured by HPLC combined with bioreactor and electrochemical detection.CGR8 cells contained 1.08±0.12 pmol acetylcholine/10(6) cells (n=7) which was reduced to 0.50±0.06 pmol/10(6) cells (n=6; p0.05) in the presence (4h) of 30μM bromoacetylcholine to block choline acetyltransferase. A time-dependent release of acetylcholine into the incubation medium was dem…
Effect of coronary perfusion rate on the hydrolysis of exogenous and endogenous acetylcholine in the isolated heart
1977
1. The effect of perfusion rate on the hydrolysis of acetylcholine in isolated chicken hearts was studied by measuring both the spontaneous and the evoked output of endogenous acetylcholine into the perfusate in response to vagal stimulation and the arterio-venous difference of exogenous acetylcholine. 2. A decrease in the perfusion rate from 30 to 20 and 10 ml/min caused a graded and significant decline of both the spontaneous overflow of acetylcholine and the overflow evoked by stimulation of both vagus nerves (20 Hz, 1 ms, 40V) for 20 min. The spontaneous and evoked overflow at 30 ml/min were 2 and 3 times, respectively, the overflow at 10 ml/min. 3. Physostigmine (10−6M) raised both the…
Release of non-neuronal acetylcholine from the human placenta: difference to neuronal acetylcholine
2001
The synthesis and release of non-neuronal acetylcholine, a widely expressed signaling molecule, were investigated in the human placenta. This tissue is free of cholinergic neurons, i.e. a contamination of neuronal acetylcholine can be excluded. The villus showed a choline acetyltransferase (ChAT) activity of 0.65 nmol/mg protein per h and contained 500 nmol acetylcholine/g dry weight. In the absence of cholinesterase inhibitors the release of acetylcholine from isolated villus pieces amounted to 1.3 nmol/g wet weight per 10 min corresponding to a fractional release rate of 0.13% per min. The following substances did not significantly modify the release of acetylcholine: oxotremorine (1 micr…
Acetylcholine overflow during infusion of a high potassium-low sodium solution into the perfused chicken heart in the absence and presence of physost…
1977
1. The effect of infusion of a modified Tyrode's solution (“high K+-low Na+ solution”) into the isolated chicken heart on the content of acetylcholine in the tissue and the overflow of acetylcholine were compared to those evoked by vagal stimulation. 2. The release of acetylcholine was measured over 15-min periods of either stimulation of the vagus nerves (40 V, 1 ms) at 20 Hz or of infusion of the high K+-low Na+ solution (108 mM K+, 44 mM Na+). 3. Both stimuli caused a maximum overflow of acetylcholine in the first few minutes whether or not 10−6 M physostigmine was present. The overflow was maintained during the vagal stimulation at a constant rate of at least 35% the initial rate, where…