Effect of Irradiation on Microparticles in Red Blood Cell Concentrates

Changes in microparticles (MP) from red blood cell (RBC) concentrates in the context of irradiation have not been investigated. The aim of this study was to evaluate how irradiation affects the number of MPs within transfusion components. Twenty RBC concentrates, within 14 days after donation, were exposed to gamma rays (dose rate: 25 cGy) from a cesium-137 irradiator. Flow cytometry was used to determine the numbers of MPs derived from RBC concentrates before and 24 hr after irradiation. The mean number of MPs (±standard deviation) in RBC concentrates was 21.9×10(9)/L (±22.7×10(9)/L), and the total number of MPs ranged from 2.6×10(9)/L to 96.9×10(9)/L. The mean number of MPs increased to 22.6×10(9)/L (±31.6×10(9)/L) after irradiation. Before irradiation, the CD41-positive and CD235a-positive MPs constituted 9.5% (1.0×10(9)/L) and 2.2% (263×10(6)/L) of total MPs, respectively. After irradiation, CD41-positive MPs increased to 12.1% (1.5×10(9)/L) (P=0.014), but the CD235a-positive MPs decreased to 2.0% (214×10(6)/L) of the total MPs (P=0.369). Irradiation increases the number of CD41-positive MPs within RBC concentrates, suggesting the irradiation of RBC concentrates could be associated with thrombotic risk of circulating blood through the numerical change.

Effect of amifostine on proliferation and differentiation of human megakaryocyte Dami cells / 中国药理学与毒理学杂志

OBJECTIVE To investigate the effect of amifostine(Amf)on the differentiation of human megakaryocyte cell line-Dami. METHODS Dami cells were treated with Amf 0.01-5.0 mmol · L-1 for 12 d. Dami cells were counted every day for the growth curve:only cells with a diameter>20μm. The platelet demarcation membrane system was observed by transmission electron microscopy. The expression of CD33,CD34,CD41a and DNA ploidy was detected by flow cytometry. RESULTS Amf 0.1-1.0 mmol · L-1 promoted the differentiation of Dami cells ,but inhibited their proliferation at a concentration>1.0 mmol · L-1. When these cells were treated with Amf 1.0 mmol · L-1 for 12 d,the platelet demarcation membrane system was observed,the percentage of cells with a diameter >20 μm was increased by 24.6%(P1.0 mmol·L-1).

Study on micromegakaryocytes of patients with myelodysplastic syndrome by flow cytometry / 重庆医学

Objective To setup a measurement of human bone marrow micromegakaryocyte which based on CD41a and PI double‐labeled flow cytometric analysis ,and study the significance in the diagnosis of MDS .Methods In 42 cases of MDS patients , their bone marrow megakaryocytes were obtained by Percoll density gradient separation medium .The megakaryocyte glycoproteinⅡb/Ⅲa(CD41a)were marked with fluorescein isothiocyanate through its corresponding monoclonal antibody ,and their DNA were marked with PI .Then the megakaryocyte ploidy was analyzed by flow cytometry(FCM ) .Results The method for micromegakaryo‐cyte identification and analysis was established .In 42 patients with MDS ,the detection rate of micromegakaryocyte was 90 .5 per‐cent by FCM analysis ,but only 54 .8 percent by Wright‐Giemsa staining test and 64 .3 percent by immunohistochemistry ,the differ‐ence among them was statistically significant(χ2 = 13 .640 ,P= 0 .001) .The 42 patients with MDS were divided into two groups (low‐risk group and high‐risk group) .The detection rates of micromegakaryocyte were 81 .8 percent in low‐risk group and 100 per‐cent in high‐risk group separately by FCM analysis ,the difference was statistically significant(χ2 =4 .019 ,P=0 .045) .Conclusion The detection rate of micromegakaryocyte by FCM with CD41a and PI double marker is higher than that by cytochemical staining . The detection rate of micromegakaryocyte in the high‐risk group is higher than that of the low‐risk group ,which shows that the de‐tection of micromegakaryocyte is of great significance for MDS prognosis assessment .

Roles of CD5+, CD19+, CD41a+, CD55+ and CD59+ in Chronic Immune Thrombocytopenic Purpura (ITP).

Aims: The aim of this study was to investigate of the roles of CD5+ and CD19+ on lymphocytes, CD5+ on B lymphocytes, CD41a+ on platelets and CD55+ and CD59+ on erythrocytes in platelet destruction; and evaluate them according to the patient response status to steroid therapy and platelet counts in chronic immune thrombocytopenic purpura (ITP). Study Design: This study included 20 chronic ITP patients and 20 healthy controls. We investigated the roles of CD5+ and CD19+ expression on lymphocytes, CD5+ expression on B lymphocytes, CD41a+ expression on platelets, and CD55+ and CD59+ expression on erythrocytes, as well as the platelet counts in healthy and chronic ITP patients. Additionally, these markers were evaluated according to the patient response status to steroid therapy and platelet counts. Place and Duration of Study: This study took place at the Department of Internal Medicine and Haematology, Meram Medical Faculty at Selçuk University in Turkey, between November, 2008 and July, 2009. Methodology: A total of 40 patients (26 women, 14 men, age range: 19-79 years) were studied. The study group included 20 chronic ITP patients (12 women and 8 men, age range: 19-78 years) and the control group included 20 healthy volunteers (14 women and 6 men, age range: 22-79 years). The platelet counts and expressions of CD5+ and CD19+ on lymphocytes, CD5+ on B lymphocytes, CD41a+ on platelets, and CD55+ and CD59+ on erythrocytes were analysed in the patients and control subjects. The chronic ITP patients were evaluated according to their requirements of treatment. Five patients whose platelet counts were above 50,000 mm–3 were observed without treatment. The other 15 patients whose platelet counts were under 50.000 mm–3 and had bleeding, or whose platelet counts were under 20,000 mm–3, were given methylprednisolone treatments (1 mg/kg/day orally). Three of the 15 patients discontinued treatment for various reasons. The twelve patients who continued the methylprednisolone treatment were divided into two subgroups according to their responder status of steroid treatment. The patients whose platelet counts slowly increased above 30,000 mm–3 within three months included the steroid treatment responder subgroups. The chronic ITP patients were also divided into two subgroups according to the severity of their thrombocytopenia. The limit of the platelet count was 30,000 mm–3 for severe thrombocytopenia. These parameters were analysed according to the response status of the steroid treatment and platelet counts. The platelet counts, and the expressions of these markers, were compared between the subgroups. Results: The level of CD5+ on B lymphocyte expression (2.19 ± 1.65) in peripheral blood lymphocytes was significantly higher in the immune thrombocytopenic purpura patients than in the controls (P = .05). The CD55+ + CD59+ expression on erythrocytes (98.03 ± 1.77) was significantly higher in the ITP patients than in the controls (P = .05). There was no significant relationship between the expression of CD5+, CD19+ or CD5+ on B lymphocytes, CD41a+ expression on platelets or CD55+ and CD59+ expression on erythrocytes, according to the response status to steroid therapy in the patient group (P > 0.05). Additionally, the patients were evaluated according to platelet counts, and there was a significantly positive correlation between the level of CD41a+ expression on the platelets and the platelet count (P = .05). Conclusion: The level of CD5+ on B lymphocytes was significantly higher in the ITP patients than in the controls. A relationship between CD55+ plus CD59+ expression on erythrocytes and immune destruction of platelets was not observed in the chronic ITP patients.

Changes of platelet function after clopidogrel discontinuation in patients with percutaneous coronary interventions / 重庆医学

Objective To investigate the changes of platelet aggregation rate and platelet surface CD 41+CD62P+ expression af-ter clopidogrel discontinuation in the patients with percutaneous coronary interventions (PCI)) .Methods The platelet aggregation rates and platelet surface CD41+CD62P+ in 52 PCI patients with oral clopidogrel for near 12 months and discontinuation soon were measured before clopidogrel therapy(T0 ) ,in 1 week after clopidogrel therapy(T1 ) ,1 week before clopidogrel discontinuation(T2 ) , 1 week(T3 ) and 1 month after clopidogrel discontinuation (T4 ) .Results Compared with T0 ,the platelet aggregation rate and the expression of platelet CD41+CD62P+ at T1 were significantly decreased ,the difference showing statistical significance (P<0 .05) , which at T2 maintained the lower levels ;which at T3 were increased ,which at T4 were recovered to those at T0 .The platelet aggre-gation rates at various time points were (44 .20 ± 18 .36)% ,(25 .38 ± 12 .10)% ,(23 .74 ± 8 .15)% ,(51 .79 ± 10 .55)% and(45 .97 ± 16 .42)% respectively ,and the positive rates of CD41+ CD62P+ were(12 .96 ± 11 .48)% ,(3 .93 ± 3 .33)% ,(4 .72 ± 3 .14)% , (13 .90 ± 10 .38)% and(10 .84 ± 8 .13)% ,respectively .Conclusion In the patients treated with 12-month clopidogrel after PCI ,the platelet aggregation rate and the CD41+CD62P+ positive rate are mildly increased at 1 week after clopidogrel discontinuation and gradually returned to the level before discontinuation at 1 month after clopidogrel discontinuation .

Influence of cooling rate on qualtiy of cryopreserved platelets / 第二军医大学学报

Objective: To observe the outcomes of different cooling rates in the cryopreservation of platelets, so as to screen the best cooling rate for cyropreservation of platelets. Methods: Platelet concentrate was cooled down with the new cryopreserving solution at various cooling rates(1, 10, 20°C/min) and was kept at ∼80°C for one week. Then platelets were thawed to check platelet count, adrenaline induced aggregation, and expression of CD41, CD42b and CD62p; the results were compared with those of the non-programmed cooling group and fresh platelets. Results: The platelet counts of cryopreserved groups were lower than that of fresh platelet concentrate (P<0.05 or P<0.01). There were no differences in adrenaline induced aggregation between 10°C/min group, 1 °C/min group, and non-programmed cooling group; and the aggregation of the former 3 groups was lower than that of 1 °C/min group(P<0.01) and higher than that of 20 °C/min group (P<0.05). The CD42b expression in 10 °C/min group was higher than in other groups (P<0.05) and lower than in fresh platelet concentrate. The CD62p expression in 1 °C/min group, 20 °C/min group, none programme cooling group was higher than in fresh platelet concentrate (P<0.05). The CD62p ex: ression in 10 °C/min group was higher than other 3 groups (P<0.05) and lower than in fresh platelet concentrate, with no statistical significance. Conclusion. Cooling rate has great impact on the quality of cryopreservted platelets. Compared with 1 °C/min and 20 °C/min, 10 °C/min is the optimal cooling rate with the new cryopreservation solution in this study.

EDTA Inhibits the Binding of Clone 96.2C1, an Anti-CD41a Monoclonal Antibody, to the Platelets and Addition of Heparin and CaCl2 to the Antibody Neutralizes the EDTA-induced Inhibitory Effect

BACKGROUND: The binding of some monoclonal antibodies platelet glycoprotein (GP) IIb/IIIa, which is frequently used for flow cytometric immnophenotyping, is known to be inhibited by EDTA. To select the ideal antibodies to be included in the 'Acute Leukemia Panel' for immunophenotyping of acute leukemia, we compared the inhibitory effect of EDTA on the binding of 5 different clones of monoclonal antibodies to platelet GP IIb/IIIa. We also discovered a simple method to neutralize this inhibitory effect. METHODS: Flow cytometric measurement of the number of platelet GP IIb/IIIa binding sites with different anticoagulants was performed using a panel of 5 clones of monoclonal antibodies against CD41 (clone PM6/248), CD41a (clone 96.2C1 & clone HIP8), CD41b (clone HIP2) and CD61 (clone VI-PL2), and the results are expressed as the mean equivalent soluble fluorochrome (MESF) values. RESULTS: The MESF value of the EDTA platelets stained with anti-CD41a, clone 96.2C1 antibody showed a significantly lower value than the MESF of platelets anticoagulated with heparin or citrate (P<0.001). The inhibitory effect of EDTA on the binding of anti-CD41a, clone 96.2C1 antibody to the platelets was neutralized by addition of heparin and CaCl2. The mean MESF value of EDTA platelets stained with anti-CD41a, clone 96.2C1 antibody was significantly increased by the addition of heparin and CaCl2 (P=0.0001). CONCLUSION: The false-negative results of the binding of anti-CD41a, clone 96.2C1 antibody to the platelets seem to be due to the calcium chelating property of EDTA, and the addition of CaCl2 and heparin could be used as an easy compensatory measure for the inhibitory effect of EDTA on other antibodies as well.

Estimate of Thrombopoiesis by Flow Cytometric Analysis of Reticulated Platelets in Patients with Severe Thrombocytopenia / 대한진단검사의학회지

BACKGROUND: Analysis of reticulated platelets (RPs) is useful for discriminating the causes of thrombocytopenia and monitoring the thrombopoiesis. In the patients with severe thrombocytopenia, we evaluated the thrombopoiesis-discriminating ability of several indices applying forward scatter (FSC) and thiazole orange (TO) fluorescence in addition to the percentage of reticulated platelets (RPs%). METHODS: Forty cases with decreased thrombopoiesis, twenty cases with increased thrombopoiesis and twenty cases with liver cirrhosis were selected. By flow cytometry with two analytic methods, dependent on or independent of the staining of CD41-PE as a platelet marker, the primary parameters including RPs% were measured and the applied parameters were calculated from them. And we compared the diagnostic efficiency of each parameter and analyzed the purity of platelet light scatter gate. RESULTS: The purity of platelet light scatter gate was significantly lower in patients with severe thrombocytopenia than in healthy persons with normal platelet counts (P<10(-6)), so the use of CD41-PE for platelet gating improved the diagnostic efficiency of RPs%. Compared to the primary parameters, the applied parameters originated from RPs%, FSC and TO fluorescence improved diagnostic efficiency significantly (RPs%: 55%, RPs%xs delta MFI: 80%) between decreased and increased thrombopoiesis groups. CONCLUSIONS: In the patients with severe thrombocytopenia, the estimate of the thrombopoiesis by a flow cytometric analysis can be more predictable by using platelet markers and by considering the fluorescence intensity of TO together with the RPs%.

High-efficient genetic transfection of CD41~+,UT7,U937 and MDA-MB-435 cells with a recombined murine stem cell retroviral vector / 中国病理生理杂志

AIM: Gene transduction with a recombined murine stem cell retroviral vector has been investigated to find an effective way of gene transduction and to offer theory and experimental basis for the recombined murine stem cell retroviral vector used for gene transduction. METHODS: 1. Construction of retrovirus vector: EC1-4 gene (repeats 1-4 of cadherin-5 extracellular domain) and mutant (Ser 222A) MEK1 gene were cloned into retrovirus vector pMSCV after cut by Bgl Ⅱ and EcoR 1 restriction endonuclease. 2. Obtaining CD41 + cells and cell culture: Cells expressing CD34 + from cord blood were isolated. The inducement of cells expressing CD41 from CD34 + cells was performed by using TPO and cells CD41 + were selected by FACS. NIH 3T3 cells were cultured in high sugar DMEM medium and U937 in RPMI 1640 medium. UT7 cells which is cytokine-dependent cell line were grown in Iscove's modified Dulbeco's medium supplemented by GM-CSF. 3. Determination of viral titers: Retroviral vectors were transferred to packaging cell line 293. Retroviral containing supenatant was collected after transfection. The viral titers was tested on infection of NIH 3T3 cells by FACS analysis. 4. Western blot: Transduced CD41 +,UT7,U937 and MDA-MB-435 cells were analyzed by western blot to examine expression of transduced genes. RESULTS: A packaging cell line 293 produces high-titer MEK1 pMSCV retroviruses (3.1?10 7) and EC1-4 pMSCV retroviruses (1.0?10 8). With 8-folds dilution retroviruses,60.73% GFP positive cells have been obtained in MEK1 pMSCV transduced UT7 cells,72.56% in U937 cells and 30.57% in CD41 + cells,respectively. GFP positive cells have reached up 97.54 % in EC1-4 pMSCV transducted MDA-MB-435 cells. Phosphorylated MEK1 has been decreased in experiment group when TPO has stimulated CD41 + and UT7 cells or serum has stimulated U973 cells. This indicates that is a dominant negative effect of mutation MEK gene. EC1-4 gene transduced MDA-MB-435 cells have expressed EC1-4. CONCLUSION: The recombined murine stem cell retrovirus can effectively mediate gene transduction of CD41 +,UT7,U937 and MDA-MB-435 cells,and transduced genes can be stably expressed.