The effects of U-74389G, a 21-aminosteroid, on pulmonary vascular resistance after a scald.
We tested U-74389G (C37H50N6O2-CH4O4), a 21-aminosteroid, to determine whether it ameliorates the pulmonary vascular effects of a surface scald. We studied 24-anesthetized rabbits mechanically ventilated with 100% and then 13% O2. Twelve rabbits received a scald (75 degrees C water applied to the shaved ventral surface for 90 seconds), and 12 served as control (20 degrees C water). Six control and six scalded animals additionally received U-74389G (5 mg/ kg intravenously). We measured hemodynamics and blood gases prescald, 30 minutes postscald, and 30 minutes after U-74389G or placebo administration. The strength of hypoxic pulmonary vasoconstriction (HPV) was assessed as the difference between pulmonary vascular resistance measured during 13% O2 ventilation and during 100% O2 ventilation. Hemodynamics and gas exchange were similar between groups. The strength of HPV was significantly diminished postscald, but U-74389G treatment restored HPV to baseline values. We conclude that a scald reduces the strength of HPV, and the response to U-74389G suggests this may be mediated by free radicals.
Johnson
D H
DH
University of Saskatchewan, Saskatoon, Canada.
Hurst
T S
TS
Mayers
I
I
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology* / Q000627:therapeutic use; D002056:Burns / Q000150:complications / Q000188:drug therapy*; D005609:Free Radicals / Q000378:metabolism; D006439:Hemodynamics / Q000187:drug effects; D000860:Hypoxia; D008168:Lung / Q000098:blood supply*; D011281:Pregnatrienes / Q000494:pharmacology* / Q000627:therapeutic use; D011817:Rabbits; D012131:Respiratory Insufficiency / Q000188:drug therapy / Q000209:etiology; D014655:Vascular Resistance / Q000187:drug effects*; D014661:Vasoconstriction / Q000187:drug effects*
D000975:Antioxidants; D005609:Free Radicals; D011281:Pregnatrienes; C074965:U 74389F