成人髂骨钉钉道的影像学研究

目的对中国成人髂后上棘至髂前下棘髂骨锚固通道各参数进行影像学测量，探讨髂骨钉置入的可行性与安全性。方法应用多层螺旋CT对60名中国成人进行髂骨三维重建，在斜侧位图像上测量双侧髂后上棘至髂前下棘连线全长及此连线与坐骨切迹上顶点的距离，在沿该连线截面图像上测量双侧钉道通路中髂骨两个狭窄点松质骨与皮质骨的厚度、髂后上棘至第二狭窄点的长度等影像学参数。结果参数均值的95％置信区间：髂后上棘至髂前下棘全长为（140．6±1．1）mm，髂后上棘咬除深度男性为（16．9±0．6）mm、女性为（15．9±0．8）mm，过第二狭窄点长度男性为（67．1±0．6）mm、女性为（70．1±1．4）mm，坐骨切迹上顶点到髂后上棘-髂前下棘连线距离为（18．3±0．8）mm，第一狭窄点松质骨厚度男性为（11．0±0．7）mm、女性为（9．0±0．8）mm，皮质骨厚度男性为（17．3±0．6）mm、女性为（15．7±0．7）mm，第二狭窄点松质骨厚度男性为（11．8±0．7）mm、女性为（8．1±0．7）mm，皮质骨厚度男性为（22．7±0.3）mm、女性为（19．1±0．8）mm。各参数变异度较大，且除髂后上棘至髂前下棘全长及坐骨切迹到该通道高度外，其余各参数男女间差异均有统计学意义。结论成人髂骨由髂后上棘至髂前下棘存在一个直线骨性钉道通路，且该钉道通路中有两个狭窄点，对髂骨钉起锚固作用，通过两个狭窄点的髂骨钉可保证进钉安全性。     

Aspirin protected against endothelial damage induced by LDL： role of endogenous NO synthase inhibitors in rats

AIM: To study the protective effect of aspirin on damages of the endothelium induced by low-density lipoprotein (LDL), and whether the protective effect of aspirin is related to reduction of nitric oxide synthase inhibitor level.METHODS: Vascular endothelial injury was induced by a single injection of native LDL (4 mg/kg) in rats. Vasodilator responses to acetylcholine (ACh) in the isolated aortic rings were determined, and serum concentrations ofasymmetric dimethylarginine (ADMA), malondialdehyde (MDA), tumour necrosis factor-α (TNF-α), and the activity of dimethylaminohydrolase (DDAH) were measured. RESULTS: A single injection of LDL (4 mg/kg)significantly decreased vasodilator responses to ACh, increased the serum level of ADMA, MDA, and TNF-α, anddecreased DDAH activity. Aspirin (30 or 100 mg/kg) markedly reduced the inhibition of vasodilator responses toACh by LDL, and the protective effect of aspirin at the lower dose was greater compared with high-dose aspiringroup. Aspirin inhibited the increased level of MDA and TNF-α induced by LDL. Aspirin at the dose of 30 mg/kg,but not at higher dose (100 mg/kg), significantly reduced the concentration of ADMA and increased the activity ofDDAH. CONCLUSION: Aspirin at the lower dose (30 mg/kg) protects the endothelium against damages elicitedby LDL in vivo, and the protective effect of aspirin on endothelium is related to reduction of ADMA concentrationby increasing DDAH activity.     

Cellules endothéliales circulantes, microparticules et progéniteurs : vers la définition de la « vasculocompétence »

Exposure to deleterious processes of metabolic, infectious, autoimmune or mechanical origin, alters the endothelium which progresses towards a proinflammatory and procoagulant activation, senescence and apoptosis. This “response to injury” of the endothelium plays a key role in the initiation and progression of cardiovascular disorders. In the last 10 years, identification in peripheral blood of circulating endothelial cells (CEC) and endothelial-derived microparticles (EMP) reflecting endothelium damage has led to the development of new noninvasive methods for endothelium exploration. Indeed, these biomarkers were associated with most of the cardiovascular risk factors, were correlated with established parameters of endothelial dysfunction, and were indicative of a poor clinical outcome. Moreover, they behave as biological vectors able to disseminate deleterious signals in the vascular compartment. More recently, this concept has been enlarged by the discovery of a potent repair mechanism based on the recruitment of the circulating endothelial progenitors cells (EPC) from the bone marrow, able to regenerate injured endothelial cells. Cardiovascular risk factors alter EPC number and function. Because the damage/repair balance plays a critical role in the endothelium homeostasis, CEC, EMP and EPC could be combined in an endothelium phenotype that defines the “vascular competence” of each individual. In the future, progress in standardization of available methodologies to measure these emerging biomarkers is a crucial step to establish their clinical interest for assessment of vascular risk and monitoring of vascular-directed therapeutics.     

An endogenous dithiol with antioxidant properties: alpha-lipoic acid, potential uses in cardiovascular diseases

Alpha-Lipoic acid (ALA) is a natural compound, chemically named 1,2-dithiolane-3-pentanoic acid, also referred to as thioctic acid. In humans, ALA is synthetized by the liver and other tissues with high metabolic activity: heart, kidney. ALA is both water and fat soluble and therefore, is widely distributed in both cellular membranes and cytosol. Recently, a greater deal of attention has been given to antioxidant function for ALA and its reduced formed: dihydrolipoic acid (DHLA). ALA scavenges hydroxyl radicals, hypochlorous acid and singlet oxygen. It may also exert antioxidant effects in biological systems through transitional metal chelation. Dihydrolipoic acid has been shown to have antioxidant but also pro-oxidant properties in systems in which hydroxyl radical was generated. ALA/DHLA ratio has the capacity to recycle endogenous antioxidants such as vitamin E. A number of experimental as well as clinical studies point to the usefulness of ALA as a therapeutic agent for such diverse conditions as diabetes, atherosclerosis, insulin resistance, neuropathy, neurodegenerative diseases and ischemia-reperfusion injury. ALA represents a potential agent on the vascular endothelium, recording to ALA/DHLA redox couple is one of the most powerful biological antioxidant systems.     

Dietary flavonoids and human health

Due to antioxidant properties linked to their polyphenolic structure, dietary flavonoids are supposed to protect the organism against deleterious effects of environmental oxidants. Indeed prospective epidemiologic studies on cohorts have shown inverse correlations between consumption of some foods or beverages with high flavonoid content, (especially flavanols and anthocyanins), and coronary stroke mortality or prevalence of neurodegenerative diseases including Alzheimer's and Parkinson's diseases. These include red wine, some grape juices, red fruits, tea and cocoa, The hypothesis of cause effect relationship between dietary flavonoid intake and observed protection is further supported by several short term controlled randomised clinical trials. However composition of ingested food or beverage is complex and poorly defined, especially their content in different flavonoids. In addition, knowledge on bioavailability of these compounds and their fate in the organism is still limited. The best documented effect is protection or restoration of the vascular endothelium function, principally involving nitric oxide (*NO). It is not established that ingested flavonoids produce a direct antioxidant effect in vivo. By contrast, at the cell level, some flavonoids can modify protein kinases mediated signal transmission, thereby inducing antioxidant and anti-inflammatory genes expression, and, vice versa, inhibiting oxidant and inflammatory gene expression. Presently available information and the important health challenge justify enhanced research in the field.     

Sickle red cell adhesion: Many issues and some answers

Among multiple pathologies associated with sickle cell disease, sickle red cell-endothelial interaction has been implicated as a potential initiating mechanism in vaso-occlusive events that characterize this disease. Vast literature exists on various aspects of sickle red cell adhesion, but many issues remain unresolved, especially pertaining to the role of sickle red cell heterogeneity, the relative role of multiple adhesion mechanisms and targets of antiadhesive therapy. This review briefly analyzes these issues.