[Distribution of N-isopropyl-p-[I-123]iodoamphetamine among the peripheral blood components: an in vitro study].
With the purpose to clarify dynamics of N-isopropyl-p-[I-123]iodoamphetamine (I-123 IMP) in the blood stream its binding to the peripheral blood components was determined by in vitro experiment. I-123 IMP was added to the peripheral venous blood obtained from healthy volunteers to be incubated for different length of time (0-30 min) at 37 degrees C. The blood was then separated into blood cells and plasma. From the latter platelet rich plasma were separated. Radioactivity in each blood component was counted in a well type scintillation counter respectively. To evaluate the affinity of I-123 IMP to red blood cell the component containing blood cells were washed repeatedly with salines. It was found that the fraction of radioactivity in the blood cell component was 68.0 +/- 6.3% (m +/- 1 S.D.), which was higher than that in the plasma (32.0% +/- 6.3%). The radioactivity in the platelet-rich plasma was only 1.7 +/- 1.1% of the total I-123 IMP activity. This percentage did not change by the incubation time. When Tc-99m DTPA was incubated with blood, radioactivity in the blood cell component was only 22.5%, which is further lowered by 32 +/- 2.1% after each washing to reach 6.8% after three times washing. In contrast the radioactivity of I-123 IMP in blood cell component remained as high as 31.1% after eight times washing. Almost constant fraction (8.20 +/- 0.57%) of radioactivity was freed into supernate by each washing. These findings suggest that a certain specific binding mechanism is involved in the binding of I-123 IMP to red blood cells.
Department of Respiratory Medicine, Kanto Teishin Hospital, Tokyo, Japan.
S
S
Kumazaki
N
N
Oriuchi
K
K
Tomiyoshi
T
T
Inoue
Y
Y
Sasaki
D000662:Amphetamines / Q000493:pharmacokinetics*; D001773:Blood Cells / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D020367:Iofetamine; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D004369:Pentetic Acid / Q000493:pharmacokinetics; D010949:Plasma / Q000378:metabolism*; D016284:Technetium Tc 99m Pentetate
D000662:Amphetamines; D007457:Iodine Radioisotopes; D015609:Organotechnetium Compounds; D004369:Pentetic Acid; D020367:Iofetamine; D016284:Technetium Tc 99m Pentetate