In vitro platelet adhesion to vascular subendothelium: studies in patients with polycythaemia vera.
In this work we studied platelet adhesion to subendothelial surfaces in 10 patients with polycythaemia vera and 10 healthy volunteers at 40% Hct (corresponding to the mean value of our control group) and 55% Hct (a value roughly corresponding to the mean Hct in polycythaemic patients). Platelet concentration was kept constant at 2.0-2.5 X 10(11)/l. The results indicate that there was a statistically significant increase in adhesion both in controls and in patients with Hct varying from 40% to 55%. The contribution of the higher Hct in promoting platelet adhesion was comparable in the two groups. When red blood cells (RBC) from the patients were tested with platelets from healthy volunteers in cross-over experiments, they promoted adhesion in the same way as control RBC. Similarly, when patients' platelets were mixed with control RBC, adhesion was the same as control platelets. These data indicate that platelet and RBC contribution to this parameter are not significantly modified in this group of polycythaemic patients, provided that platelet and RBC values are adjusted to control range.
Lauri
D
D
Vascular Physiopathology Unit, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy.
Dejana
E
E
Cortelazzo
S
S
Orlando
E
E
Zanetti
A
A
Viero
P
P
de Gaetano
G
G
Barbui
T
T
D000328:Adult; D000368:Aged; D000375:Aging; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged; D010973:Platelet Adhesiveness; D010976:Platelet Count; D011087:Polycythemia Vera / Q000097:blood* / Q000503:physiopathology