Search results for "Permeability"
showing 10 items of 596 documents
Stabilization of Perivascular Mast Cells by Endothelial CNP (C-Type Natriuretic Peptide)
2020
Objective: Activated perivascular mast cells (MCs) participate in different cardiovascular diseases. Many factors provoking MC degranulation have been described, while physiological counterregulators are barely known. Endothelial CNP (C-type natriuretic peptide) participates in the maintenance of vascular barrier integrity, but the target cells and mechanisms are unclear. Here, we studied whether MCs are regulated by CNP. Approach and Results: In cultured human and murine MCs, CNP activated its specific GC (guanylyl cyclase)-B receptor and cyclic GMP signaling. This enhanced cyclic GMP–dependent phosphorylation of the cytoskeleton-associated VASP (vasodilator-stimulated phosphoprotein) and…
Pancreatic ascites haemoglobin up-regulates the HIF/VEGF pathway in the lung in severe acute pancreatitis
2015
Extracellular haemoglobin (EHb) is considered a toxic molecule due to its cytotoxicity and peroxidase activity. EHb may release free hemin that increases vascular permeability, leukocyte recruitment, and adhesion molecule expression. Pancreatitis-associated ascitic fluid is reddish and may contain cell-free hemoglobin. Our aim was to determine the role of EHb in the local and systemic inflammatory response during severe acute pancreatitis in rats. To this end, taurocholate-induced necrotizing pancreatitis in rats was used. EHb levels were quantified in ascites and plasma and the hemolytic action of ascitic fluid was tested. Furthermore, we assessed if peritoneal lavage prevented the increas…
Rolipram inhibits airway microvascular leakage induced by platelet-activating factor, histamine and bradykinin in guinea-pigs.
1993
Abstract Rolipram (0·1–1000 μg kg−1, i.v.) reduced the increase in microvascular permeability induced by platelet-activating factor (PAF; 50 ng kg−1, i.v.) at different sites of the guinea-pig airways. Rolipram (1–100μg kg−1, i.v.) inhibited histamine (30μg kg−1, i.v.)-and bradykinin (0·3 μg kg, i.v.)-induced airway microvascular leakage. These effects of rolipram were obtained at doses which inhibit histamine (7–20 μg kg−1 min−1)-induced bronchoconstriction (IC50 = 3 ± 1 μg kg, i.v.) without depressing arterial blood pressure in the guinea-pig. Aminophylline (50 mg kg−1) did not change the effect of PAF. The anti-exudative effect of rolipram is of potential therapeutic value in asthma.
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.
Kinin receptors in human vascular tissue: their role in atheromatous disease
1997
Using samples of many human blood vessels, obtained at autopsy and specific antibodies directed to peptide sequences of the kinin B1 and B2 receptors, we demonstrate the localisation of these receptors within the human vascular system using standard immunolabelling techniques. In large elastic arteries and veins, kinin receptors are present only in the endothelial cells whereas in all muscular arteries and arterioles, these receptors are present in both the endothelial and smooth muscle cells. The identification of kinin receptors in human blood vessels confirms that kinins may modulate both vascular permeability and contractility. The incidental finding at histology, of patchy atheromatous…
An exploratory study of two Caco-2 cell models for oral absorption: A report on their within-laboratory and between-laboratory variability, and their…
2010
In 2005, the European Centre for the Validation of Alternative Methods (ECVAM) sponsored a study aimed at evaluating the reproducibility (between-laboratory and within-laboratory variability) and the predictive capacity of two in vitro cellular systems — the Caco-2/ATCC parental cell line and the Caco-2/TC7 clone — for estimating the oral fraction absorbed (Fa) in humans. Two laboratories, both of which had experience with Caco-2 cultures, participated in the study. Ten test chemicals with documented in vivo oral absorption data were selected. Atenolol, cimetidine and propranolol were included as reference compounds for low, medium and high intestinal absorption, respectively. Transport ex…
Adriamycin Permeability of the Rat Bladder under Different Conditions
1983
Abstract Fifty female Sprague-Dawley rats were treated with 1.4 or 2.4 mg. adriamycin intravesically. Radioimmunological measurement of serum concentrations were performed up to 3 hours post-instillation in normal bladder mucosa, cystitis, and after electrocoagulation, under different filling conditions, as well as with the use of a detergent (Tween 80). The serum concentrations achieved were markedly higher after electrocoagulation or cystitis; altogether they reached only 1/6,000 of the instilled concentration. These studies on the rat bladder suggest that perioperative instillation of adriamycin to prevent recurrence is not contraindicated shortly before or after transurethral resection …
Sicilian pistachio (Pistacia vera L.) nut inhibits expression and release of inflammatory mediators and reverts the increase of paracellular permeabi…
2014
Background Dietary approaches to control inflammatory bowel diseases (IBD) may include proanthocyanidin-rich foods. Our previous research showed that a hydrophilic extract from Sicilian pistachio nut (HPE) contains sub- stantial amounts of proanthocyanidins and possesses anti- inflammatory activities. Purpose We studied the effects of HPE and of its poly- meric proanthocyanidin fraction (PPF) in a cell model that simulated some conditions of IBD, consisting of interleukin (IL)-1b-stimulated Caco-2 cells. Methods HPE was prepared by Pistacia vera L. nuts, and PPF was isolated from HPE by adsorbance chromatogra- phy. Proanthocyanidins were quantified as anthocyanidins after acidic hydrolysis.…
Ethyl hexanoate transfer in paper and plastic food packaging by sorption and permeation experiments
2008
The barrier properties of one treated paper packaging and one standard plastic film (bi-oriented polypropylene, biOPP) were assessed for ethyl hexanoate. Three methods based either on sorption (gravimetry and micro-atmosphere-derived method) or permeation kinetic determination were used in controlled conditions of aroma vapor concentration (107 Pa), temperature (25 degrees C) and relative humidity (about 0 %). Ethyl hexanoate solubility values were on the same range of magnitude for both packaging films in spite of their different nature and composition. Ethyl hexanoate affinity for both films was well predicted by their respective solubility parameters. Solubility values were different acc…
Buccal Thin Films as Potent Permeation Enhancers for Cytisine Transbuccal Delivery
2022
Cytisine (CYT) is a powerful anti-smoking compound which could greatly benefit from transbuccal delivery because of both its unfavorable pharmacokinetics after oral administration and its intrinsic ability to permeate the buccal mucosa. This work aims to design CYT-loaded buccal thin films suitable for transbuccal drug delivery due to its capability of promoting the interaction between CYT and the buccal membrane. The solvent casting method was employed to prepare several thin films combining various excipients such as matrixing polymers, mucoadhesion agents, plasticizers and other compounds as humectants and sweeteners, component ratios and solvents. A total of 36 compositions was prepared…