The role of clinical drug trial methodology with respect to studies of new drugs. Clinical trials of timolol

The use of the Randomized Clinical Trial (RCT) to assess the safety and efficacy of a new drug or treatment can provide a clear evaluation of the relative benefits and risks of the new therapy as compared to the longer-established treatment methodology. In some cases, such as insulin, the benefits are immediately apparent; in other cases, such as photocoagulation for proliferative diabetic retinopathy, the consensus is not so easily obtained, and the clinical trial can supply the answer. Furthermore, the RCT provides the opportunity to identify adverse reactions, in particular those which present with a seemingly unrelated or unexpected set of symptoms. In conducting clinical trials of timolol, researchers must be alert for beta-adrenergic antagonist effects, such as were seen with practolol, and should be especially careful to note early, mild reactions which may be the forerunners of later, more severe or irreversible adverse effects.     

Laser-induced thermal injury to dermal blood vessels: analysis of wavelength (585 nm vs. 595 nm), cryogen spray cooling, and wound healing effects

BACKGROUND AND OBJECTIVES: Successful laser treatment of cutaneous hyper-vascular lesions requires appropriate laser irradiation parameters for selective photothermolysis of ectatic dermal blood vessels as well as appropriate cooling parameters for epidermal protection based on an individual patient basis. Using the rabbit ear as an in vivo model for dermal vasculature, we investigated the influences of laser wavelength (585 nm vs. 595 nm) and cryogen spray cooling with various spurt durations on the laser-induced thermal injury to dermal blood vessels. Wound healing response was also evaluated in 2 hours and 4 days. STUDY DESIGN/MATERIALS AND METHODS: Flashlamp-pumped pulsed dye laser ScleroPlus (operated at the wavelength of 585 or 595 nm) was used for the comparison between the influences of two wavelengths (585 nm vs. 595 nm). R134-a cryogen spurts with the durations from 50 to 300 milliseconds were sprayed onto the sites to be irradiated and terminated 20 milliseconds before the onset of the laser pulses. In vivo rabbit ear was used as the model for cutaneous hyper-vascular lesions. Totally 10 New Zealand Albino white rabbits were experimented and in each rabbit ear six to seven sites were irradiated. Five animals were sacrificed 2 hours after the irradiation, and the remaining five sacrificed 4 days after the irradiation. Thermal injury to the blood vessel was assessed by hematoxylin and eosin stained histological sections and confirmed by an apoptosis assay. RESULTS: When the radiant exposures were above 10 J/cm2, 595 nm wavelength induced equivalent or more severe thermal injury to dermal blood vessels than 585 nm. Cryogen spray cooling with the spurt durations above 100 milliseconds resulted in increased depth of the most superficial thermal injury to dermal blood vessels than without cooling, indicating that superficial blood vessels were non-specifically cooled by the cryogen spurts applied at these parameters. Laser-induced thermal injury was significantly healed in the rabbit ear vasculature at 4 days post irradiation. CONCLUSIONS: Given sufficient radiant exposure, 595 nm wavelength can induce equivalent or more severe vascular injury compared with 585 nm. Cryogen spray cooling with the spurt durations above 100 ms may impair the photocoagulation of superficial blood vessels. Irreversible thermal injury to blood vessel can be achieved only when the basement membrane of blood vessel wall is irreversibly damaged.     

Argon laser intraocular photocoagulation

Argon laser intraocular photocoagulation is now available during vitreous surgery, to treat retinal breaks and to give panretinal photocoagulation. Twenty patients, including phakic patients with gas-filled eyes, were treated using a new operative contact lens without complication. This intraoperative technique allows controlled rapid application of laser lesions at a safe distance from the retina, and eliminated the need for attempting treatment through the often hazy media of an irritated postoperative eye. A group of five rhesus monkeys were treated with various power settings to assess the histopathologic features of these laser lesions.     

Diabetic retinopathy — Need and demand for photocoagulation and its cost-effectiveness: Evaluation based on services in the United Kingdom

Summary Photocoagulation services in the two Regions, north of the River Thames, treated 6,589 cases of diabetic retinopathy (including an annual incidence of 309 cases) or 20% of the estimated total need for photocoagulation. Sixty-one percent of diabetic retinopathy patients have disease in both eyes. It is cheaper to treat a patient with diabetic retinopathy than to look after a blind person for one year. Hence, adequate training in the identification and early treatment of diabetic retinopathy requiring photocoagulation is urgent.     

A cross-platform model for secure Electronic Health Record communication

During the past decade, there have been many regional, national and European projects focused on the development of platforms for secure access and sharing of distributed patient information. A platform is needed because present local or enterprise-wide information systems are typically not intended for cross-organisational secure access of patient data. Most of the present secure platforms are local or regional. Commonly used platform types in the health care environment vary from secure point-to-point communication systems to internet-based portals. This paper defines an enhanced cross-security platform which makes it possible for different kinds of local, regional, and national health information systems to communicate in a secure way. The proposed evolutionary way interconnects regional or national security domains with the help of a cross-platform zone. A more revolutionary model based on peer-to-peer Grid like networks and dynamic security credentials is also discussed. The proposed evolutionary model uses cross-domain security and interoperability services to ensure secure communication and interoperability between different security domains. The platform supports both communication defined beforehand and adhoc dynamic access to distributed electronic health records (EHRs). The internet is proposed as the "glue" between different regional or national security domains.     

Status of hyperthermia in the treatment of advanced liver cancer

The vast majority of patients with malignant liver tumors have inoperable disease. These patients must rely on chemotherapy, radiotherapy, and various locoregional treatments. Although these treatments have demonstrated encouraging response rates, symptom palliation and occasional down staging of tumors, their impact on survival is minor. As a result there has been renewed interest in hyperthermia as a treatment option. This study reviews the current modalities of hyperthermia in terms of clinical results, side effects, limitations, and therapeutic standing.     

激光光凝治疗糖尿病性视网膜病变疗效分析

目的:探讨激光光凝治疗糖尿病性视网膜病变的治疗效果。方法:对我院近3a 176例320眼的糖尿病性视网膜病变,经行激光光凝治疗后,定期观察视力,眼底及眼底荧光造影检查(3 ～4mo),记录新生血管、视网膜出血渗出、玻璃体积血等情况,观察期4mo～3a。结果:完成激光治疗后1mo,视力提高≥2行139眼(43.4)%,无变化123眼(38.4)%,视力下降≤2行58眼(28.1)%。造影示新生血管消退307眼(95.9%),3眼新生血管性青光眼,虹膜新生血管消退,眼压正常。28眼(8.8%)发生玻璃体积血,后行玻璃体切割,术中补激光。结论:激光光凝是治疗糖尿病性视网膜病变的有效方法。     

光学相干断层扫描对氩激光治疗糖尿病性黄斑水肿的疗效观察

目的应用光学相干断层扫描观察氩激光治疗糖尿病性黄斑水肿的临床疗效。方法对糖尿病性黄斑水肿患者行氩激光光凝术。在光凝前、光凝后3个月分别进行扫描获取光学相干断层扫描图像,记录黄斑中心凹视网膜厚度,作统计学分析。结果平均随访(3.0±0.6)个月。光凝前及光凝后3个月黄斑中心凹区视网膜厚度平均值分别为(397±102)μm和(204±90)μm,差异有统计学意义。结论光学相干断层扫描检测能较准确定量测算黄斑区视网膜厚度,可对比观察氩激光光凝前后视网膜厚度变化,进而判断氩激光光凝的疗效。     

早期全视网膜光凝治疗缺血型视网膜中央静脉阻塞

目的　评价早期预防性全视网膜光凝治疗缺血型视网膜静脉阻塞的有效性和安全性。方法　用氩离子激光器 ,对病史短于 3个月的缺血型视网膜静脉阻塞 2 1例 2 1眼 ,行全视网膜光凝 ,10 0 0～ 2 0 0 0个光凝点 (平均15 0 7点 )分 3～ 5次完成。观察光凝前后眼部新生血管的消退和视力变化情况 ,以及远期并发症的发生情况。结果　随访 3个月至 2年 ,平均 18 4个月。无一例发生虹膜新生血管和新生血管性青光眼 ;发生玻璃体出血 2例 ;治疗后视力与治疗前比较差异无显著意义 (P >0 0 5 )。结论　早期全视网膜光凝预防和减少由缺血型视网膜静脉阻塞引起的并发症是有效的 ,能为部分患者赢得治疗时间     

Depressive tendency of design major freshman students explored through the use of color in mosaic creations

Depression is affecting a growing number of people, while the age of its first occurrence continues to lower; there is a rapid increase in youths with depression. Many therapies use art as a tool; the process of creation allows the therapist to understand the thoughts and feelings of depression patients. This study quantifies the color usage principles and abstract feelings from the perspective of the artist, and further considers whether there are differences in color cognition between those with or without depressive tendencies. The participants were 120 college freshman design students, and the CES-D was used to test the subjects’ degree of depression. Afterwards, the subjects were asked to participate in creating a mosaic with the theme “different selves,” and to offer their own explanation of the principles and feelings related to the use of color in the creative work. One-third of the 120 subjects had depressive tendencies. The results showed a correlation between depressive tendency and the use of color in the “different selves” mosaic, with subjects having depressive tendencies showing a greater use of dark colors. Those subjects with no depressive tendencies were more likely to use “cool colors” to represent depression, while those subjects with depressive tendencies more often used “dark colors” to express depression. This study found that there is a correlation between the presence of depressive tendency and this specific use of color among freshman design students.