Pharmacologic vitreolysis with microplasmin increases vitreous diffusion coefficients

Background Pharmacologic vitreolysis is a new approach to improve vitreo-retinal surgery and ultimately to liquefy and detach the vitreous from the retina to eliminate the contribution of the vitreous to retinopathy. The mechanism of action of the agents being developed for pharmacologic vitreolysis remains unclear. The effect of microplasmin on vitreous diffusion coefficients was investigated using the non-invasive technique of dynamic light scattering (DLS). Methods Vitreous diffusion coefficients in 18 intact porcine eyes were measured in vitro with dynamic light scattering (DLS). DLS was performed on all specimens at 37 °C 30 min after injections of human recombinant microplasmin at doses ranging from 0.125 to 0.8 mg, with 20-nm tracer nanospheres. Results DLS findings in untreated porcine vitreous were similar to the previously described findings in bovine and human vitreous. Microplasmin increased porcine vitreous diffusion coefficients in a dose-dependent manner (correlation coefficient, r=0.93), with an 85% increase after a 30-min exposure to the maximum dose. Conclusions Pharmacologic vitreolysis with human recombinant microplasmin increases vitreous diffusion coefficients in vitro. The results of these studies have implications for the dosing, route of administration, duration of action and methods of determining efficacy in future studies of pharmacologic vitreolysis to enhance vitreo-retinal surgery, as well as the design of clinical trials to induce prophylactic posterior vitreous detachment. This work is an abridgement of a thesis submitted in partial fulfillment of requirements for membership in the American Ophthalmological Society, May 2005.     

高度近视眼继发视网膜劈裂与玻璃体-视网膜牵引的关系

目的 观察高度近视眼继发视网膜劈裂在OCT上的特征,分析其发生的原因。方法 回顾2000-10/2003-03因中心视力减退在我院进行过OCT检查的高度近视26例43眼,对其中存在继发性视网膜劈裂的12例18眼(42%)的OCT图像进行分析。结果 高度近视眼继发视网膜劈裂以外层劈裂为主,多发生在眼底后极部(16/18),多数(15/18)可见玻璃体牵引视网膜征象。所有黄斑区尚未被视网膜劈裂累及眼的黄斑中心凹处的视网膜感觉层较同龄、同性别的正常人薄,有统计学意义(P=0.0052)。结论 高度近视眼继发视网膜劈裂并不少见,它与玻璃体牵引及视网膜本身的退行性变密切相关。     

原发性玻璃体后脱离致视网膜裂孔的治疗探讨

目的 分析玻璃体后脱离所致视网膜裂孔的确诊时间及不同处理对其预后的影响。方法 2000年10月至2002年8月对95例(95眼)由急性玻璃体后脱离所致视网膜裂孔眼进行临床分析。裂孔已导致视网膜脱离的行视网膜复位手术，干性视网膜裂孔行532激光封闭裂孔术。结果 59例伴有视网膜脱离的患者明确诊断时间长，经手术治疗(部分为玻璃体手术)后视功能有一定的恢复，但有些病人需多次手术。35例视网膜干性裂孔患者诊断及时，经光凝治疗后视力无明显改变。结论 玻璃体后脱离导致视网膜裂孔早期诊断，及时光凝是为患眼争取良好预后的关键。     

Recent advances in hemodynamics

The use of the pressure sensor coronary guidewire is expanding into the peripheral circulation as well as into the realm of valvular heart disease. Small mechanistic studies and case reports have described the use of pressure wire technology in the renal and femoral arteries as well as in mechanical aortic valves. The use of this technology to measure hemodynamically significant stenoses in noncoronary locations will be discussed and a review of basic and more advanced hemodynamics in relation to problems encountered in clinical practice will be provided. © 2008 Wiley‐Liss, Inc.     

Heparin-mediated extracorporeal low-density lipoprotein precipitation: rationale for a specific adjuvant therapy in cardiovascular disease

Various radical measures for the treatment of severe hypercholesterolemia such as partial ileal bypass, portocaval shunt, liver transplantation and plasma exchange have been tested in patients in whom drug and diet failed or were insufficient. Although effective, most of these treatments have severe side effects and are not routinely used. For hypercholesterolemic patients LDL-apheresis has proved to be the most promising and safe way as an adjuvant therapy. Several LDL-apheresis procedures with a varying degree of selectivity and efficiency have subsequently been developed. One of them is the H.E.L.P. system which was introduced in 1984 and has now been widely used. Besides the marked reduction of LDL particles by all techniques it has become apparent that only the H.E.L.P. system results in an equally significant change in hemostaseology, hemorheology and vasomotion because of its simultaneously removal of LDL, Lp(a), fibrinogen and CRP. This contribution reviews the application of the H.E.L.P. system as a valuable therapeutic tool for the treatment of various atherothrombotic and microcirculatory disorders such as prevention of early graft occlusion after coronary artery bypass grafting, treatment of peripheral vascular disease, stroke and preeclampsia.