阿斯匹林与尼莫地平合用对兔体外血小板聚集的影响

目的：观察阿斯匹林与尼莫地平合用对兔体外血小板聚集的影响。方法：比浊法。结果：两药合用后均可显著提高对三种诱导剂诱导的血小板聚集的抑制作用，合用后ｑ值均大于１。结论：两药合用后可协同抑制体外血小板聚集。     

The proportion of reticulated platelets is higher in bone marrow than in peripheral blood in haematological patients.

Since the detection that platelets originate from megakaryocytes (MK), the site of megakaryocyte fragmentation has been disputed. Some authors have even postulated that platelets are solely produced in the lungs. Thus, we have directly measured platelet generation in the bone marrow (BM) by comparing the relative number of young RNA-containing, so-called reticulated platelets (%RP) in the BM and in the peripheral blood (PB). Two separate prospective, cross sectional trials have been conducted in patients routinely undergoing BM biopsies for diagnostic purposes. In the first part of the study 30 patients with stem cell or bone marrow transplantation were examined. The second part of the study was performed in 62 haematological patients visiting the outpatient's clinic. Median %RP were higher in BM than in PB (p <0.001). In the second part of the study the difference averaged 133% (interquartile range: 30-383%). There was a moderate correlation between %RP in BM and in PB (r = 0.67; p <0.001). The absolute number of RP in PB correlated weakly with the number of megakaryocytes (0.42; p = 0.001), which was due to a correlation between the platelet counts and the megakaryocyte counts (r = 0.55; p <0.001 in biopsies). Two patients with autoimmune antibodies against GPIIb/IIIa exhibited 10% and 16% RP in PB, and had 29% and 59% RP in BM, respectively. It is concluded that the relative number of RP is significantly higher in BM than in blood. This supports the notion that platelets are at least in part released from MK in the bone marrow, particularly in patients suffering from immune thrombocytopenia.     

Erythrocyte storage in hypertonic (SAGM) or isotonic (PAGGSM) conservation medium: influence on cell properties

Background and Objectives Prolonged red blood cell (RBC) storage may be associated with increased post-transfusion morbidity and mortality. A contributing factor is RBC storage lesions. We analysed the role of additive conservation solutions, either hypertonic or isotonic, on such cell properties. Materials and Methods After blood donation in citrate–phosphate–dextrose as an anticoagulant, 10 RBC units were stored with saline–adenine–glucose–mannitol (SAGM; 376 mOsm/l) and 10 units with phosphate–adenine–glucose–guanosin–saline–mannitol (PAGGSM; 285 mOsm/l). Measurements were made on days 1 and 42 of storage. Results The mean cellular volume measured by centrifuged microhaematocrit increased from 87·6 ± 3·1 fl to 100·7 ± 4·3 fl in PAGGSM and to 92·2 ± 2·5 fl in SAGM (P < 0·001) on day 1, after 42 days it was 95·8 ± 4·0 fl and 93·8 ± 3·9 fl, respectively. Spontaneous haemolysis and osmotic fragility were lower after storage in PAGGSM. Both additives showed a similar degree of echinocytosis, decreased RBC aggregability and deformability, and increased RBC suspension viscosity after storage. Conclusions The isotonic PAGGSM prevented the initial RBC swelling caused by citrate–phosphate–dextrose less than hypertonic SAGM, but reduced the spontaneous haemolysis rate and osmotic fragility after 42 days of storage. All other parameters, such as echinocytosis, decreased RBC deformability and aggregability, and increased blood viscosity was similar for both additive solutions and remained a major problem of blood banking.     

The ultrasonic detection of platelet aggregates

The echogenicity of platelet aggregates in platelet-rich plasma and whole blood was evaluated in stirring and flowing in vitro models. Real-time two dimensional ultrasonic images were obtained with transducers operating at 3.0, 5.0, 10 and 12 mHz. Platelet-rich plasma was not echogenic. The addition of adenosine diphosphate (ADP) resulted in the formation of multiple, discrete echoes that increased in size and intensity. This echogenicity was time and dose-dependent and could be quantitated by videodensitometry. Whole blood was echogenic, but the addition of ADP resulted in a time and dose-dependent increase in the size and echogenicity of the reflections. The overall echogenicity of whole blood declined with the development of platelet aggregates. There is inter- and intra-aggregate variability in the echogenicity of aggregates. Aggregates were best seen with transducers operating at the higher frequencies. These results imply that the detection of in vivo platelet aggregates may be feasible with ultrasonic imaging.     

Elevation of platelet cyclic AMP level by thromboxane A2/prostaglandin H2 receptor agonists.

Arachidonic acid (AA)-or thromboxane A₂/prostaglandin H₂ (TXA₂/ PGH₂) analog (STA₂ and U-46619)-induced aggregations yielded a bell-shaped dose-response curve. The inhibitory mechanism by high concentrations of the agonists was examined. STA₂ elevated cAMP level of platelet in a dose-dependent manner. And the aggregation was affected by metabolic inhibitors of cAMP. AA also rised cAMP level, and the rise was suppressed by indomethacin. These results indicate that the reduction of aggregation by high dose of the agonists is through cAMP elevation. The cAMP elevation was not suppressed by ruling out phospholipase C effects by chelation of cytoplasmic Ca²⁺ and inhibition of protein kinase C (PKC). These results suggest that the cAMP elevation is not due to activation of phospholipase C-linked TXA₂/PGH₂ receptor. 13-APA, an antagonist of TXA₂/PGH₂ receptor, suppressed the cAMP elevation, although ONO-3708, another antagonist, had no effect. As to be expected from this result, inhibitory effect of 13-APA on high STA₂ level-induced aggregation was weaker than that of ONO-3708. The antagonists did not inhibit PGE,- or PGD₂-induced cAMP elevation. These findings suggest that platelet has adenylate cyclase-linked TXA₂/PGH₂ receptor.     

ADP-induced second wave aggregation in platelet rich plasma from hypercholesterolemic rabbits

Platelet aggregation, ATP secretion and thromboxane formation were measured in platelet-rich plasma (PRP) of rabbits fed a cholesterol-rich (1%) diet for 3 months. Addition of ADP (0.6 – 2 μM) resulted in a clear biphasic aggregation in 7/8 cholesterol-fed rabbits. This was not seen in any of the 9 control animals kept on a standard diet for the same period of time (P < 0.01). The secondary ADP-induced aggregation was irreversible and was accompanied by enhanced ATP secretion and significant thromboxane generation. There was no ADP-induced thromboxane formation and only a minor ATP secretion at the highest ADP concentration studied (20 μM) in control rabbits. These data confirm platelet hyperreactivity in hypercholesterolemia and demonstrate for the first time the occurence of an ADP-induced second wave aggregation and granule secretion in citrated PRP of rabbits which may be triggered by thromboxane generation.     

粉防己碱对血小板聚集、粘附及血凝的影响

在体外实验中观测到粉防己碱可明显抑制ADP和胶原诱导的大鼠血小板聚集反应。对血小板粘附、血栓形成有明显抑制作用,而对凝血酶凝血时间、血浆凝固时间无明显影响。     

老年高血压患者血小板活化检测及临床意义

为探讨老年高血压患者血小板活化及其临床意义，采用流式细胞术（FCM）以单克隆抗体分子作为分子探针检测健康老年人及老年高血压无并发症患者血小板膜上糖蛋白GPⅡa/Ⅲa(PAC-1)及P－选择素（CD62P）的表达量。结果表明，老年高血压患者血小板膜上PAC－1的表达量较健康老年人高（P＜0．01），与当日平均血压无相关关系，而CD62P的表达量与健康对照组比较差异无显著性意义。提示通过FCM检测血小板膜上PAC－1的表达量，可了解高血压患者体内血小板活化度，对临床用抗血小板药有指导意义。     

右归丸的一些药理作用

右归丸是《景岳全书》中的一复方。药理实验证明:右归能增强小鼠单核吞噬细胞系统廓清功能;抑制CCl_4所致小鼠SGPT和肝脏过氧化脂质的升高;增强小鼠的耐力;对抗东莨菪碱所致小鼠记忆的障碍和对抗ADP诱导的大鼠血小板聚集。     

Platelet 5-HT uptake in post-stroke depression

Serotonin (5-HT) uptake into platelets is reduced in functionally depressed patients. Depression following stroke (cerebrovascular accident; CVA) is common and severe. Sixteen patients who had suffered a CVA within 6 to 12 months and who were medication-free had blood taken for measurement of platelet 5-HT uptake. Seven of these patients were depressed. These were compared with age- and sex-matched hospital controls. No difference in platelet 5-HT uptake was found across these groups.