Nedocromil sodium reduces cigarette smoke-induced bronchoconstrictor hyperresponsiveness to substance P in the guinea-pig.

Acute exposure to cigarette smoke provokes airway hyperresponsiveness to substance P and inactivates neutral endopeptidase (NEP). To determine whether nedocromil sodium can prevent cigarette smoke-induced hyperresponsiveness to substance P, we studied two groups of anaesthetized guinea-pigs. One group of guinea-pigs was pretreated with aerosolized 0.

Respiratory epithelial permeability in complete Freund's adjuvant rat lung granulomatosis.

To investigate Freund's adjuvant-induced changes in respiratory epithelial permeability, we determined the respiratory epithelium clearance of 99mTc-DTPA (RC-DTPA) in rats and the localization of horseradish peroxidase (HRP) across the lung epithelium. RC-DTPA was determined before and after intravenous injection of saline (control) or complete Freund's adjuvant (CFA). Although the respiratory epithelium was not disrupted, RC-DTPA was increased 15 min after injection of CFA and was still high after 3 d but had returned to normal after 7 d, after which it again increased and stayed high from Day 42 through Day 112.

Tachykinins increase respiratory clearance of 99mTc-DTPA. Mechanisms of action.

We investigated the effects of tachykinins on the respiratory clearance of 99mTc-DTPA (RC-DTPA) in anesthetized and ventilated guinea pigs. We measured the change in RC-DTPA and in maximal pulmonary insufflation pressure (PIPmax) induced by substance P, neurokinin A, and capsaicin. Substance P, neurokinin A, and capsaicin increased both PIPmax and RC-DTPA in a concentration-dependent fashion.

Influence of Pneumocystis carinii pneumonia on serum and tissue concentrations of pentamidine administered to rats by tracheal injections.

Pentamidine isethionate was administered by the tracheal route to control rats and immunodepressed rats with Pneumocystis carinii pneumonia (PCP). The serum concentration of pentamidine base 20 min after the administration was higher in the PCP rats (309 +/- 165 ng/ml) than in the control animals (71 +/- 36 mg/ml; p less than 0.001); 90 min after the injection the proportion of the pentamidine administered was lower in the right lung of the PCP rats (29 +/- 15%) than in the control rats (57 +/- 23%; p = 0.

Effects of tobacco smoke on respiratory epithelial clearance of DTPA and on lung histology in rats.

The respiratory epithelial clearance of 99mTc-(DTPA) diethylenetriamine penta-acetate (RC-DTPA) was measured in rats before and after sham or cigarette smoke exposures. RC-DTPA was increased by cigarette smoke exposure (p less than 0.001); the amount and duration of the exposure had no significant effect.