In vitro platelet activation by an echo contrast agent.
OBJECTIVE
We investigated whether an ultrasonic echo contrast agent containing microbubbles (Levovist [SH U 508A]; Schering AG, Berlin, Germany) could in routine use activate platelets.


METHODS
Levovist and its main component, galactose, were mixed with separate samples of whole blood (1.5-75 mg/mL) from 5 healthy volunteers to form a 1-mL suspension sample. After in vitro exposure to ultrasound emitted from a commercial ultrasonic scanner at a pulse frequency of 3.5 MHz with a mechanical index of 1.9 and an exposure duration of 5 minutes, 5 microL of the sample was incubated for 20 minutes with the fluorescein isothiocyanate-labeled CD61 antibody, which is a platelet-specific antigen, and the phycoerythrin-labeled CD62P (P-selectin) antibody, an activation-specific antigen, both on the platelet surface. After more than 30 minutes of fixing in 1% paraformaldehyde, flow cytometric analysis was performed.


RESULTS
The percentage of CD62P-expressing platelets increased according to the concentrations of Levovist and galactose, which showed almost equal effects. Ultrasound exposure did not enhance the effect except at the highest concentration of Levovist (75 mg/mL).


CONCLUSIONS
In vitro, a galactose-based echo contrast agent could not activate the platelets at its routine concentration.
Shigeta
Kouichirou
K
Department of Clinical Laboratory Medicine, Jichi Medical School, Tochigi-ken, Japan.
Taniguchi
Nobuyuki
N
Omoto
Kiyoka
K
Madoiwa
Seiji
S
Sakata
Yoichi
Y
Mori
Masaki
M
Hatake
Kiyohiko
K
Itoh
Kouichi
K
D000328:Adult; D001772:Blood Cell Count; D003287:Contrast Media / Q000494:pharmacology*; D005434:Flow Cytometry; D005690:Galactose / Q000032:analysis; D006801:Humans; D008297:Male; D019007:P-Selectin / Q000032:analysis; D015539:Platelet Activation / Q000187:drug effects*; D011134:Polysaccharides / Q000494:pharmacology*
D003287:Contrast Media; D019007:P-Selectin; D011134:Polysaccharides; C059891:SHU 508; D005690:Galactose