Objective.To establish a flow cytometric internal standard method for counting platelet-derived microparti-cles(PMPs)and to study its clinical significance. Methods. PMPs suspension(platelet poor plasma,PPP) was extra...Objective.To establish a flow cytometric internal standard method for counting platelet-derived microparti-cles(PMPs)and to study its clinical significance. Methods. PMPs suspension(platelet poor plasma,PPP) was extracted by gradual centrifugation. According to the size of PMPs,3 μm and 0.8μm latex beads were used as internal standards for the quantitation. PMPs were counted by adjusting flow cytometric discrimination and voltage of forward scatter and side scatter. Results. In 30 healthy donors,the average concentration of resting PMPs was(1.2×105±5.7×104 )/ml and that of activated PMPs was(1.6×106±9.1×105)/ml. Compared with healthy donors,PMPs mean value was significantly higher(P< 0.001)in 18 patients with coronary artery disease,12 with acute cerebral infraction and 23 with chronic renal failure[the average PMPs concentration,( 6.1×105±2.5×105 )/ml, ( 6.8×105±3.4×105)/ml and(5.9×105±3.1×105)/ml respectively]. However,no significant difference in PMPs concentration was observed in 25 patients with acute leukemia and severe thrombocytopenia during the aplastic phase after chemotherapy [1.3×105±6.1×104)/ml,(P >0.05)] .Conclusions. PMPs is a useful indicator in monitoring platelet activation,and plays an important role in thrombotic disease. By flow cytometric internal standard method,PMPs can be counted rapidly and accurately,which may be very helpful in interlaboratory comparative studies.展开更多
BACKGROUND： Infection-induced thrombocytopenia （TCP） is an independent risk factor for death of patients with sepsis, but its mechanism is unknown. This study aimed to explore the underlying mechanism of TCP based ...BACKGROUND： Infection-induced thrombocytopenia （TCP） is an independent risk factor for death of patients with sepsis, but its mechanism is unknown. This study aimed to explore the underlying mechanism of TCP based on the relationship between TLR4 expression and platelet activation in septic patients. METHODS： A total of 64 patients with sepsis were prospectively studied. Platelet count （PC）, mean platelet volume （MPV）, platelet distribution width （PDW）, platelet TLR4 expression, platelet PAC-1 expression, sCD40L and TNF-a concentrations were compared between the healthy control group （15 volunteers） and sepsis group （64 patients） at admission and on the 3, 5, and 9 days after admission. The changes of MPV and PDW in the TCP and non-TCP subgroups of sepsis before and after treatment were recorded. Prognostic index was analyzed. RESULTS：PC was lower in the sepsis group （P=0.006）, and MPV and PDW were higher in the sepsis group than those in the healthy control group （P=0.046, P=0.001）. Platelet TLR4 and PAC-1 expressions, and sCD40L and TNF-a levels increased more significantly in the sepsis group （P〈0.001）. PAC-1 expression and TNF-a level were higher in the TCP group than in the non-TCP group before and after treatment （P=0.023, P=0.011）. sCD40L concentration and platelet TLR4 expression were significantly higher in the treated TCP group than in the non-TCP group （P=0.047, P=0.001）. Compared to the non-TCP group, the rate of bleeding was higher （P=0.024） and the length of ICU stay was longer （P=0.013）. The APACHE II score and the 28-day mortality were higher in the TCP group （P〈0.01, P=0.048）. CONCLUSIONS：The elevation of platelet TLR4 expression in sepsis along with platelet activation is closely related to the incidence of thrombocytopenia. The occurrence of TCP is a sign of poor prognosis in sepsis patients.展开更多
文摘Objective.To establish a flow cytometric internal standard method for counting platelet-derived microparti-cles(PMPs)and to study its clinical significance. Methods. PMPs suspension(platelet poor plasma,PPP) was extracted by gradual centrifugation. According to the size of PMPs,3 μm and 0.8μm latex beads were used as internal standards for the quantitation. PMPs were counted by adjusting flow cytometric discrimination and voltage of forward scatter and side scatter. Results. In 30 healthy donors,the average concentration of resting PMPs was(1.2×105±5.7×104 )/ml and that of activated PMPs was(1.6×106±9.1×105)/ml. Compared with healthy donors,PMPs mean value was significantly higher(P< 0.001)in 18 patients with coronary artery disease,12 with acute cerebral infraction and 23 with chronic renal failure[the average PMPs concentration,( 6.1×105±2.5×105 )/ml, ( 6.8×105±3.4×105)/ml and(5.9×105±3.1×105)/ml respectively]. However,no significant difference in PMPs concentration was observed in 25 patients with acute leukemia and severe thrombocytopenia during the aplastic phase after chemotherapy [1.3×105±6.1×104)/ml,(P >0.05)] .Conclusions. PMPs is a useful indicator in monitoring platelet activation,and plays an important role in thrombotic disease. By flow cytometric internal standard method,PMPs can be counted rapidly and accurately,which may be very helpful in interlaboratory comparative studies.
文摘BACKGROUND： Infection-induced thrombocytopenia （TCP） is an independent risk factor for death of patients with sepsis, but its mechanism is unknown. This study aimed to explore the underlying mechanism of TCP based on the relationship between TLR4 expression and platelet activation in septic patients. METHODS： A total of 64 patients with sepsis were prospectively studied. Platelet count （PC）, mean platelet volume （MPV）, platelet distribution width （PDW）, platelet TLR4 expression, platelet PAC-1 expression, sCD40L and TNF-a concentrations were compared between the healthy control group （15 volunteers） and sepsis group （64 patients） at admission and on the 3, 5, and 9 days after admission. The changes of MPV and PDW in the TCP and non-TCP subgroups of sepsis before and after treatment were recorded. Prognostic index was analyzed. RESULTS：PC was lower in the sepsis group （P=0.006）, and MPV and PDW were higher in the sepsis group than those in the healthy control group （P=0.046, P=0.001）. Platelet TLR4 and PAC-1 expressions, and sCD40L and TNF-a levels increased more significantly in the sepsis group （P〈0.001）. PAC-1 expression and TNF-a level were higher in the TCP group than in the non-TCP group before and after treatment （P=0.023, P=0.011）. sCD40L concentration and platelet TLR4 expression were significantly higher in the treated TCP group than in the non-TCP group （P=0.047, P=0.001）. Compared to the non-TCP group, the rate of bleeding was higher （P=0.024） and the length of ICU stay was longer （P=0.013）. The APACHE II score and the 28-day mortality were higher in the TCP group （P〈0.01, P=0.048）. CONCLUSIONS：The elevation of platelet TLR4 expression in sepsis along with platelet activation is closely related to the incidence of thrombocytopenia. The occurrence of TCP is a sign of poor prognosis in sepsis patients.
