Alterations of the levels of glycoproteins Ib-IX and IIb-IIIa in platelets stored at 22°C

Platelets stored in CLX™ blood bags, under normal blood banking conditions, were studied for up to 7 days to determine if changes ocurred in the levels of membrane glycoproteins (GP) Ib-IX and IIb-IIIa. Radiolabeled monoclonal antibodies (MAB) were used to estimate the number of glycoprotein molecules on the surface membrane of intact platelets. GP IX and GP IIb-IIIa levels remained essentially unaltered during storage. In contrast, the content of GP Ib at day 7 decreased by 45% of the total when fresh. The aggregation response to ristocetin, which requires GP Ib, was also diminished after 7 days. Addition of protease inhibitors, leupeptin and/or aprotinin did not appear to influence the degradation of this glycoprotein. We conclude that storage at 22°C has deleterious effects on the GP Ib content of platelets.     

Platelet 3H-imipramine binding during recovery from depression.

Decreased binding of tritiated imipramine to platelets has been considered to be a potential biological marker of depression. However, it has been unclear how binding values alter during treatment and recovery. This study investigated imipramine binding parameters and depressive symptoms in 25 patients suffering from major depression at entry to the study and 1, 3 and 6 months later. Although the initial Bmax values were significantly lower in the depressed patients than in healthy subjects, it was not possible to establish a clear relationship between recovery from depression and Bmax. The power of this study to detect an effect of at least 10% of the variance in Bmax due to factors related to recovery from depression was 0.78.     

Persistent platelet activation in patients with type 2 diabetes treated with low doses of aspirin

BACKGROUND: The percentage of diabetic patients who do not benefit from the protective effect of aspirin is larger than in other populations at cardiovascular risk. OBJECTIVE: We compared the ability of aspirin to suppress TxA2 and platelet activation in vivo, in type-2 diabetics vs. high-risk non-diabetic patients. METHODS: Urinary 11-dehydro-TXB2, plasma sCD40 L, and sP-selectin were measured, together with indices of low-grade inflammation, glycemic control, and lipid profile, in 82 patients with type-2 diabetes and 39 without diabetes, treated with low doses of aspirin. RESULTS: Urinary 11-dehydro-TxB2, plasma sCD40L and sP-selectin were significantly higher in diabetics than in controls: [38.9 (27.8-63.3) vs. 28.5 (22.5-43.9) ng mmol(-1) of creatinine, P = 0.02], [1.06 (0.42-3.06) vs. 0.35 (0.22-0.95) ng mL(-1); P = 0.0001], [37.0 (16.8-85.6) vs. 20.0 (11.2-35.6) ng mL(-1), P = 0.0001], respectively. The proportion of individuals with diabetes increased across quartiles of 11-dehydro-TxB2, sCD40L, and sP-selectin, with the highest quartiles of 11-dehydro-TxB2, sCD40L and sP-selectin, including 66%, 93.3%, and 93.3% of individuals with diabetes. Markers of platelet activation positively correlated with indices of glycemic control but not with markers of low-grade inflammation. CONCLUSIONS: Platelet dysfunction associated with insufficient glycemic control, may mediate persistent platelet activation under aspirin treatment.     

Deficiency of P-selectin in a patient with grey platelet syndrome

Abstract: Patient B.G. is a 29-yr-old female with a lifelong bleeding disorder characterized clinically by a highly increased bleeding time, menorrhagias, long-lasting bleeding after cuts and tooth extractions and large post-traumatic haematomas. Her coagulation tests were within normal range, platelet count was 140,000–160,000 per μl, but platelet function was impaired as demonstrated by the absence of collagen-induced aggregation, although no abnormalities were detected in aggregation response to ADP and ristocetin. Morphologically her platelets were characterized by gigantic size – average profile area was about 2.5 times higher than that of control donors, and severe deficiency of α-granules – only 16% of their number in control donors. These features taken together indicated the diagnosis of grey platelet syndrome. As has been shown by quantitative immunoblotting, patient's platelets contained small amounts of α-granule membrane protein P-selectin – about 15% of that in control donors. The content of plasma membrane glycoproteins IIb–IIIa and Ib was not reduced, suggesting the specific deficiency of α-granule membrane protein. Thus, B.G. is the second patient described in the literature (see also Lages et al, J Clin Invest 1991: 87: 919–929) with combined deficiency of α-granules and P-selectin.     

心绞痛患者血小板功能改变及丹参对其影响

本实验观察了心绞痛患者血小板环核苷酸水平,血浆TXB_2、6酮PGF_(10)深度、血小板内外5—HT含量及血小板聚集性的变化以及丹参治疗前后各指标的改变。结果表明,心绞痛患者血小板聚集性血浆5—HT和血浆TXB_2水平明显增高,而血小板内5—HT、血浆6—酮—PGF_(10)水平则明显低于对照组。丹参能增加血小板内cAMP水平,降低血浆5—HT水平,对血小板聚集性有抑制作用。     

Priming effect of RANTES on eosinophil oxidative metabolism

Background RANTES has been shown to possess chemotactic activity for eosinophils, which have also been considered to play a role in allergic inflammation through reactive oxygen species. Thus, in this study, we examined the effect of RANTES on radical oxygen products from eosinophils.
Methods Purified eosinophils by CD16-negative selection or an eosinophilic cell line (EoL-1) were incubated with or without RANTES (2.5 x 10⁻⁶). To the mixture of eosinophils and luminol, calcium ionophore (A23187) or opsonized zymosan (OZ) was added, and radical oxygen products were determined by luminol-dependent chemiluminescence for 600 s.
Results Eosinophil-mediated radical oxygen products of untreated eosinophils produced with A23187 gave a peak value of 14.09 + 2.40 (mean±SE, n = 12) relative light units (RLU) and an integrated value of 3232.20 + 513.09 RLU. However, with treatment with RANTES, a peak value of 18.66 + 2.40 RLU and an integrated value of 5301.05 ±561.02 RLU were obtained. Eosinophil oxidative metabolism-induced A23187 or OZ was apparently augmented by the preincubation with RANTES. In addition, the radical oxygen products of EoL-1 showed similar results.
Conclusions Thus, we concluded that RANTES may play an important role the pathogenesis of allergic inflammation through its involvement in eosinophil activation, as evidenced by oxygen products, as well as in selective eosinophil infiltration as selective eosinophil chemoattractant.     

合成消旋丹参素及其衍生物对血小板聚集性和cAMP含量的影响

合成消旋丹参素(简称合成丹参素)及其衍生物(BLA、BLE)在体外实验和体内静脉注射时,对ADP诱导的家兔和大鼠血小板聚集性均有明显的抑制作用。BLK和BLE有较强的促进血小板解聚作用,而合成丹参素较弱。合成丹参索、BLA和BLE在体外实验时,无升高血小板内cAMP作用,反使其cAMP含量下降。提示合成丹参素及其衍生物对血小板功能的作用,不是通过提高cAMP水平;推测可能和抑制血栓素A_2(TXA_2)合成酶有关。