Figure 2.

Experimental protocol for isolated perfused rat lungs. All perfusions were done under negative pressure ventilation. Following a 15 minute period of equilibration, during which the lungs were already ventilated and perfused, the experiment started by the inhalation of freshly produced ¹⁹²Ir-UFP from the aerosol line. Intratracheal instillation of ^99mTc-DTPA or other instillations were performed at this starting time point. The perfusate was collected continuously and sampled at 15-min time intervals. The following treatments were investigated, group 1: control group, only ¹⁹²Ir-UFP inhalation for 120 min; group 2: instillation of 50–100 μL ^99mTc-DTPA, 500 μl H₂O₂ bolus (0.5 mM), ¹⁹²Ir-UFP aerosol inhalation for 120 min; group 3: instillation of 50–100 μL ^99mTc-DTPA, histamine continuously pefrused during the next 2 hours at concentration 10 μM, ¹⁹²Ir-UFP aerosol inhalation for 120 min; group 4: instillation of 50–100 μL ^99mTc-DTPA and 500 μl histamine bolus instillation at a concentration of 10 mM, ¹⁹²Ir-UFP aerosol inhalation for 120 min; group 5: instillation of 50–100 μL ^99mTc-DTPA. For each group 3–4 animals were used.