Fibronectin binding to thrombin-stimulated platelets: evidence for fibrin(ogen) independent and dependent pathways

Plasma fibronectin binds in a specific and saturable manner to thrombin- stimulated platelets. gamma-Thrombin stimulated 80% as much fibronectin binding to platelets as alpha-thrombin with conversion of less than or equal to 1% of platelet fibrinogen to fibrin. Afibrinogenemic and normal platelets bound similar quantities of fibronectin in the presence of calcium or magnesium-ethylene glycol tetra-acetic acid (EGTA). These observations indicate that fibronectin can interact with platelets without involvement of fibrin or fibrinogen. Nevertheless, two different effects of fibrin(ogen) on fibronectin binding were observed. First, exogenous fibrinogen inhibited fibronectin binding to thrombin-stimulated platelets. This inhibition was unidirectional, as fibronectin did not inhibit fibrinogen binding to ADP or thrombin- stimulated cells. Second, formaldehyde-fixed cells with surface- associated fibrin bound significant quantities of fibronectin. This interaction required calcium and did not occur on fixed cells with or without surface-bound fibrinogen. A portion of the ligand bound to fixed cells with surface-associated fibrin was modified to form a derivative with a molecular weight identical to that of the fibronectin subunit cross-linked to the alpha-chain of fibrin. This high mol wt derivative was also observed to a variable extent with living cells in the presence of magnesium or calcium but not in the presence of magnesium-EGTA. Thus, fibronectin binds to platelets by at least two mechanisms: (1) a fibrin(ogen)-independent pathway that requires divalent ions and is inhibited by exogenous fibrinogen; and (2) a fibrin-dependent pathway with an absolute calcium requirement. With nonaggregated, thrombin-stimulated platelets, the former pathway appears to predominate.     

改良小梁切除术治疗伴有高眼压及大瞳孔的急性房角关闭

目的 评价改良小梁切除术治疗伴有高眼压及大瞳孔的急性房角关闭的临床疗效。方法收集2005年1月至2009年3月中山大学中山眼科中心青光眼专业实施改良小梁切除术治疗伴有高眼压及大瞳孔的急性房角关闭21例（21眼）的临床资料,对术后并发症及手术前后的眼压、视力、瞳孔等进行统计分析。 结果 术前眼压(48.25±3.14) mmHg,平均用降眼压药种类3.35种,明显高于出院时眼压(10.47±1.15)mmHg(t=11.4573,P＜0.01)及术后3个月眼压(13.86±0.93) mmHg(t=11.2641,P＜0.01)。出院视力(0.09±0.05)与术前视力(0.11±0.06)差异无统计学意义(沁0.8702,P= 0.3913),术后3个月视力(0.21±0.04)则稍好于术前（t=-2.7907,P=0.0112）。术前瞳孔垂直径(5.81±0.23) mm与出院时瞳孔垂直径(5.92±0.21 )mm差异无统计学意义（t=-1.5013,P=0.1672）。无严重并发症发生。 结论 改良小梁切除术是治疗伴有高眼压及大瞳孔的急性房角关闭的有效方法,术中分次放房水、巩膜瓣调节缝线、术毕形成前房等措施可有效减少严重并发症的发生。     

Inhalational anesthetics inhibit spreading depression: relevance to migraine

Cortical spreading depression (SD) has not been shown in the human neocortex by direct cortical recordings. However, animal studies suggest that cortical injury, such as that occurring during neurosurgical procedures, should result in the initiation of SD. It is possible that inhibition of SD by volatile anesthetic agents may partially explain the failure to observe SD in the human neocortex during surgery. This study examines the effect of the anesthetic agents α-chloralose, halothane, nitrous oxide and isoflurane on the initiation of cortical SD in the cat neocortex. SD was seen in 100% of cats anesthetized with α-chloralose ( n = 15), in 3 of 7 (42%) animals anesthetized with isoflurane ( p < 0.05, χ² with Yates correction) and none of the animals ( n = 4, 6 hemispheric preparations) anesthetized with halothane ( p < 0.005, χ² with Yates correction, halothane vs α-chloralose group). In all cases this inhibitory effect was reversible. In four animals the administration of nitrous oxide (66%) reduced the inspired concentration of isoflurane required to inhibit SD by 0.75%. This study suggests that halothane, and to a lesser extent isoflurane and nitrous oxide, protect against the initiation of cortical SD. This observation may partially explain why SD has not been demonstrated in human neocortex during surgery. Further studies are needed to determine if SD may occur under pathological conditions, such as during migraine with aura, where the cortex may be predisposed to SD.     

Is fecundability associated with month of birth? An analysis of 19th and early 20th century family reconstitution data from The Netherlands

The relationship between fecundability and month of birth was investigated in a cohort of 1526 women who married between 1802 and 1929, using only women whose first marriage occurred before the age of 35 years. On the basis of their time to pregnancy (TTP, calculated as time between wedding and first birth minus gestational length), women were categorized into two groups: fecunds (TTP up to 12 months or prenuptial conceptions, n = 1348) and subfecunds (TTP >18 months, n = 118). By use of logistic regression, cosinor functions with a period of 1 year or 6 months and variable shift and amplitude were fitted through the monthly odds of subfecunds versus fecunds. The best fitting curve was unimodal, with a zenith in September (P = 0.13 for H0: no differences). Exclusion of childless women (n = 36, minimum follow-up 5 years) from the subfecunds led to a similar curve (P < 0.01), while childless women, as compared with fecunds, showed a birth distribution that was best represented with a bimodal curve with zeniths in January and July (P = 0.06). This study provides evidence for the existence of differences in fecundability by month of birth. The cause of this relationship is unclear, but may lie in a melatonin-dependent circannual variability of the quality of the oocyte.      

PCT、CRP动力学评估脓毒血症预后及诊断意义的研究

目的 观察血清降钙素原(PCT)、C反应蛋白(CRP)及其动力学变化,评估其在严重脓毒症/感染性休克患者的诊断及预后价值.方法 本研究采用回顾性分析方法,2014年9月1日至2016年4月30日选择184例ICU中被诊断为严重脓毒症/感染性休克疾病患者,检测入院时血清PCT、CRP水平和治疗后第2,第3和第5天的PCT、CRP水平.结果 通过△PCT、△CRP评估PCT、CRP的动力学在存活者与死亡组中有显著性统计学意(△PCT2/0,P=0.0001;△PCT3/0,P=0.0001;△PCT5/0,P=0.0001;△CRP2/0,P=0.0069;△CRP3/0,P=0.0001;△CRP5/0,P=0.0001),在严重脓毒症和感染性休克组中也存在显著差异(PCT5,P=0.007;△PCT5/0,P=0.007).受试者工作特征曲线(ROC)模型显示,△PCT3/0(AUC=0.721)、△PCT5/0(AUC=0.77)、△CRP5/0(AUC=0.766)水平判断严重脓毒症/感染性休克患者预后有较好的临床意义.△PCT5/0 (0.619)对严重脓毒症或感染性休克有一定的辅助诊断效果,其在ROC曲线上灵敏度、特异性均较高的临界点为0.624,所以,以第5天的血清△PCT5/0水平＞0.624可作为预测感染性休克的临界点.结论 血清中PCT、CRP对严重脓毒症/感染性休克早期有较好的临床诊断及预后价值,其动力学研究可以提高对严重脓毒症/感染性休克诊断及预后评估的敏感性及准确性.