Nanoemulsions as Ophthalmic Drug Delivery Systems.

Nanoemulsions are liquid-in-liquid dispersion with a droplet size of about 100 nm. They have a transparent appearance, high rate of bioavailability, and increased shelf life. Nanoemulsions mainly consist of oil, water, surfactant, and cosurfactant and can be prepared by high- and low-energy methods.

Detection of Cl--HCO3- and Na+-H+ exchangers in human airways epithelium.

Molecular species of the Na(+)-H(+) exchanger (NHE) and anion exchanger (AE) gene families and their relative abundance in the human airway regions were assessed utilizing RT-PCR and the RNase protection assay, respectively. Organ donor lung epithelia from various bronchial regions (small, medium, and large bronchi and trachea) were harvested for RNA extraction. Gene-specific primers for the human NHE and AE isoforms were utilized for RT-PCR.

Ion transport by sheep distal airways in a miniature chamber.

Ion transport and the electric profile of distal airways of sheep lungs were studied in a miniature polypropylene chamber with a 1-mm aperture. Small airways with an inner diameter < 1 mm were isolated, opened longitudinally, and then mounted as a flat sheet onto the 1-mm aperture where it was glued and secured with an O-ring. Both sides of the tissue were bathed with identical physiological solutions at 37 degrees C and oxygenated.

Expression of the Na+/H+ and Cl-/HCO-3 exchanger isoforms in proximal and distal human airways.

Recent studies have indicated the presence of Na+/H+ and Cl-/HCO-3 exchange activities in lung alveolar and tracheal tissues of various species. To date, the identity of the Na+/H+ (NHE) and Cl-/HCO-3 (AE) exchanger isoforms and their regional distribution in human airways are not known. Molecular species of the NHE and AE gene families and their relative abundance in the human airway regions were assessed utilizing RT-PCR and the RNase protection assay, respectively.

Regulation of Na and Cl transport in sheep distal airways.

To investigate ion transport function of distal airways mucosa we dissected and isolated segments of sheep bronchioles (outside diameter 664 +/- 10 microns, means +/- SE). Both ends of a segment were cannulated with glass micropipettes, and the preparation was placed in a bath and perfused with oxygenated Krebs-Henseleit solution at 37 degrees C. Luminal amiloride (0.

Microperfusion of sheep bronchioles.

We isolated segments of sheep bronchioles (length 406 +/- 46 microns, diameter 227 +/- 53 microns, n = 27). These segments were placed in a 37 degree C bath and cannulated at both ends with glass micropipettes. The proximal end was cannulated and held by three concentrically arranged micropipettes that delivered perfusion solution by gravity.

Collapse of intercellular spaces of canine tracheal mucosa by epinephrine.

Variations in the volume and width of lateral intercellular spaces (LICS) of dog tracheal mucosa in vitro were investigated by use of stereological and linear measurements of electron micrographs. Alterations in the volume or width of LICS were then correlated with physiological conditions and electrical parameters. LICS were quite narrow between the ciliated cells compared with those around the nonciliated dark cells (goblet, brush, and basal cells).

Rectum has abnormal ion transport but normal cAMP-binding proteins in cystic fibrosis.

The luminal membranes of involved tissues in cystic fibrosis (CF) are relatively impermeable to Cl and the regulation of Cl transport by adenosine 3',5'-cyclic monophosphate (cAMP)-mediated hormones is abnormal. We investigated the human rectum as a putative model for CF. We compared in vivo transrectal potential difference (PD) in CF and in normal subjects in response to sequential perfusions with various test solutions.

Effects of taurine-conjugated bile salts on ionic transport of the rabbit esophageal mucosa.

Bile salts have been implicated as a cause of esophageal injury. We examined in vitro the changes in ionic transport of the rabbit esophagus resulting from taurine-conjugated bile salts at neutral pH to define and characterize their actions independent of hydrogen ion. In an Ussing chamber changes in potential difference (PD, mV), short-circuit current (SCC, microA X cm-2) and resistance (R, omega X cm2) resulting from taurocholate (TC), taurodeoxycholate (TDC) and taurochenodeoxycholate (TCDC) were studied.

Regulation of salt and water transport across airway mucosa.

Effective mucociliary clearance of secretions by airway mucosa requires efficient ciliary beating. The structure of airway secretions provides for this requirement by having a viscous mucous layer touched underneath and propelled by ciliary tips, while the rest of the cilium is surrounded by a serous fluid layer. The regulation of the latter layer is thought to be a function of mucosal epithelial cells capable of active ion transport.

Rapid estimation of total body clearance of theophylline in patients receiving intravenous aminophylline infusion.

The method of Chiou to rapidly estimate theophylline total body clearance using two serum concentration data during the early stage of intravenous aminophylline infusion was evaluated in 16 patients with acute exacerbation of asthma or chronic obstructive pulmonary disease. The observed serum concentrations at later times were compared with those predicted. The mean prediction error for serum concentrations was 4.

Calcium secretion in canine tracheal mucosa.

Calcium (Ca) affects many cellular functions of the respiratory tract mucosa and might alter the viscoelastic properties of mucus. To evaluate Ca homeostasis in a respiratory epithelium we investigated transport of Ca by the canine tracheal mucosa. Mucosal tissues were mounted in Ussing-type chambers and bathed with Krebs-Henseleit solution at 37 degrees C.

Substance P stimulation of chloride secretion by canine tracheal mucosa.

We investigated the effect of a neuropeptide, substance P, on the electrical and ion transport properties of dog trachea. Posterior mucosal tissues were mounted in Ussing chambers and bathed with Krebs-Henseleit solution, pH 7.4, at 37 degrees C.

Ion transport in dog tracheal mucosa: interaction between calcium and prostaglandins.

Prostaglandins E1 and F2 alpha (PGE1 and PGF2 alpha) stimulate short-circuit current (SCC), tissue conductance (G), and net Cl secretion by canine tracheal mucosa. To determine if these actions of prostaglandins require extracellular Ca we tested the effects of PGE1 and PGF2 alpha on tracheal mucosa mounted in Ussing chambers when one side of the preparation was exposed to 0.2 mM ethyleneglycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid in Krebs-Henseleit solution without Ca.

Effect of human saliva and serum on ion transport by dog tracheal mucosa. Comparison of normal subjects with cystic fibrosis patients.

It has been proposed that cystic fibrosis (CF) saliva or serum contains factors that alter ion transport in various tissues. Since CF frequently affects the lungs, and disturbances in epithelial ion transport has been proposed to contribute to the pathophysiology of pulmonary disease in CF, we investigated whether saliva or serum from CF patients could alter ion transport across airways epithelium. Canine tracheal mucosae were mounted in lucite chamber and perfused on both sides with Krebs-Henseleit solution at 37 degrees C and pH 7.

Single breath nitrogen washout in pulmonary sarcoidosis.

In 35 patients with pulmonary sarcoidosis we explored the utility of single breath nitrogen washout as a means for detecting abnormalities in airway function and intrapulmonary distribution of air. Closing volume/vital capacity ratio (CV/VC) was 21% (predicted 12.5%) in patients with only hilar adenopathy (stage I).

Pulmonary function abnormalities in systemic lupus erythematosus responsive to glucocorticoid therapy.

A patient with systemic lupus erythematosus presented with moderately severe restrictive and obstructive ventilatory defects. Therapy with steroids was associated with gradual amelioration and eventual disappearance of the obstructive component. Gas exchange showed progressive improvement over four years of steroid therapy.

Ion transport by canine tracheal mucosa: effect of elevation of cellular calcium.

Calcium is considered to be modulator of paracellular shunt pathway as well as several cell functions such as ion transport. We used calcium ionophore A23187 to study effect of mobilization of calcium on chloride and sodium transport in canine tracheal epithelium. This epithelium secretes Cl and absorbs Na under short-circuit conditions.

Role of cyclic AMP in regulation of chloride secretion by canine tracheal mucosa.

Cyclic adenosine monophosphate (cyclic AMP) mediates the action of many hormones, and it affects ion transport in several different epithelia. The effect of the analogue dibutyryl cyclic AMP was tested in canine tracheal epithelium in vitro under short-circuit conditions. This agent raised short-circuit current and electrical conductance.

Modification of Na and Cl transport in canine tracheal mucosa by prostaglandins.

We tested the effect of prostaglandins PGF2 alpha and PGE1 on the transport of 36Cl and 22Na by canine tracheal epithelium. Sheets of epithelium were mounted in Ussing chambers and short-circuited. Addition of PGF2 alpha to the mucosal side resulted in an increase of net Cl secretion from 0.

Measurement of airways closing pressure in man.

In 7 healthy males, lung static and quasi-static pressure-volume (QS-PV) curves were measured simultaneously with closing volume by the single breath N2 washout test. Comparison was made of four methods for estimation of the closing pressure (CP) at the onset of phase IV. In the first method the transpulmonary pressure (PL) that directly coincided on the tracing with onset of phase IV was measured, results varied widely with a mean of -1.

Characterization of Na-K-ATPase in dog tracheal epithelium: enzymatic and ion transport measurements.

The dog tracheal epithelium actively secretes Cl and absorbs Na. The possible dependency of this electrolyte transport on a Mg-dependent, Na-K-activated adenosine triphosphatase (Na-K-ATPase, EC 3.6.

Effect of catecholamines on ion transport in dog tracheal epithelium.

The action of adrenergic agonists on ion fluxes across the epithelium of the canine trachea was determined. Isolated sheets of tracheal mucosal membranes were mounted in Ussing-type chambers, bathed with Krebs-Henseleit solution at 37 degrees C, pH 7.4, and gassed with 5% CO2 Iin oxygen.