Functional entrapment of the popliteal artery

A case of functional entrapment missed at the initial angiogram is presented. The imaging of popliteal artery entrapment syndrome and functional entrapment is discussed. The importance of appropriate imaging is emphasized. The classification of popliteal artery entrapment syndrome is discussed and it is proposed that functional entrapment is added to the existing classification in the interest of consistent reporting.     

角膜缘干细胞移植在眼科的临床应用及发展

目的:探讨角膜缘干细胞移植的应用现状及发展前景。资料来源:应用计算机检索PUBMED 2000/2007与角膜缘干细胞移植相关的文章,检索词“limbal stem cells,transplantation”,限定文献语种为“English”;同时检索万方数据库2000/2007相关文章,检索词“角膜缘干细胞,移植”,限定文献语种为中文。资料选择:共检索到相关文献180余条,选择与角膜缘干细胞的组织生物学特征、角膜缘干细胞的体外培养以及角膜缘干细胞的临床应用相关的文章。资料提炼:将初步筛选的文章进一步查找全文,排除综述和重复文献,内容相似的选择发表在权威杂志或近3年发表的文献,无论有无对照组,观察对象为人或动物均纳入。最后共纳入37篇进行综述,其中7篇研究角膜缘干细胞的组织生物学特性,8篇介绍角膜缘干细胞的体外培养,剩余22篇文章为角膜缘干细胞移植的基础和临床研究。资料综合:角膜缘干细胞移植,可以恢复正常的角膜缘屏障功能,重建眼表的完整性;而最终改善角膜的透明性和视功能。目前开展的角膜缘干细胞移植,包括自体或异体角膜缘组织移植和体外培养的角膜缘干细胞移植。自体角膜缘干细胞的移植已成为临床上较为可靠和日益成熟的治疗方法,但来源有限,且不适合双眼角膜缘病变的患者,异体角膜缘组织移植存在排斥反应,因此自体角膜缘干细胞体外培养移植术被认为是目前较理想的角膜缘干细胞移植方法,但其远期疗效需进一步临床观察。结论:目前角膜缘干细胞移植治疗严重角膜病变的研究尚处于初步阶段,自体角膜缘干细胞移植成功率是较高,自体角膜缘干细胞培养后移植治疗眼表疾病已初步获得成功,但还存在一些问题,如角膜缘干细胞生存的微环境、培养的干细胞生理、生化的免疫特性,以及黏附、增殖、分化能力等问题尚需进一步研究。     

An audit of consent refusals in clinical research at a tertiary care center in India

Background and Rationale:

Ensuring research participants’ autonomy is one of the core ethical obligations of researchers. This fundamental principle confers on every participant the right to refuse to take part in clinical research, and the measure of the number of consent refusals could be an important metric to evaluate the quality of the informed consent process. This audit examined consent refusals among Indian participants in clinical studies done at our center.

Materials and Methods:

The number of consent refusals and their reasons in 10 studies done at our center over a 5-year period were assessed. The studies were classified by the authors according to the type of participant (healthy vs patients), type of sponsor (investigator-initiated vs pharmaceutical industry), type of study (observational vs interventional), level of risk [based on the Indian Council of Medical Research (ICMR) “Ethical Guidelines for Biomedical Research on Human Participants”], available knowledge of the intervention being studied, and each patient''s disease condition.

Results:

The overall consent refusal rate was 21%. This rate was higher among patient participants [23.8% vs. healthy people (14.9%); P = 0.002], in interventional studies [33.6% vs observational studies (7.5%); P < 0.0001], in pharmaceutical industry-sponsored studies [34.7% vs investigator-initiated studies (7.2%); P < 0.0001], and in studies with greater risk (P < 0.0001). The most common reasons for consent refusals were multiple blood collections (28%), inability to comply with the study protocol (20%), and the risks involved (20%).

Conclusion:

Our audit suggests the adequacy and reasonable quality of the informed consent process using consent refusals as a metric.KEY WORDS: Autonomy, consent, India, reason, refusal, risk     

The Safe Routes to School Program in California: An Update

Despite efforts to combat increasing rates of childhood obesity, the problem is worsening. Safe Routes to School (SRTS), an international movement motivated by the childhood obesity epidemic, seeks to increase the number of children actively commuting (walking or biking) to school by funding projects that remove barriers preventing them from doing so. We summarize the evaluation of the first phase of an ongoing SRTS program in California and discuss ways to enhance data collection.Over the past 3 decades, obesity rates have more than doubled among children and tripled among adolescents in the United States.1 Meanwhile, the percentage of students actively commuting (walking or biking) to school declined from 41% in 1969 to only 13% in 2001.2,3To counteract these trends, Safe Routes to School (SRTS), an international movement, seeks to increase the number of children who actively commute to school by funding projects that remove barriers and improve community infrastructure. With federal funding authorized by the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (Pub L No. 109-59), the California Department of Transportation invested $189 million toward SRTS efforts in the state. Of this investment, $3.8 million funded a partnership between the University of California, San Francisco, and the California Department of Public Health to form a technical assistance resource center to evaluate SRTS state-level projects targeting students in kindergarten through ninth grade.4–6 We evaluated the first phase (2008–2010) of ongoing SRTS programs representing 81 towns and cities and assessed ways to enhance data collection.     

Peroxidase-H2O2-halide system: Cytotoxic effect on mammalian tumor cells

Myeloperoxidase, H2O2, and a halide constitute a potent antimicrobial system. A cytotoxic effect of this system on a line of mouse ascitic lymphoma cells (LSTRA) is demonstrated here using four different assay systems: 51Cr release, trypan blue exclusion, inhibition of glucose C-1 oxidation, and loss of oncogenicity for mice. Deletion of each component of the system, preheating the peroxidase, or addition of azide, cyanide, or catalase abolished the cytotoxicity. Myeloperoxidase was effective with either chloride or iodide as the halide, while lastoperoxidase was effective with iodide but not chloride. The iodinated thyroid hormones, triiodothyronine and thyroxine, could substitute for the halide, and H2O2 could be replaced by a peroxide- generating enzyme system such as glucose and glucose oxidase or by H2O2 producing bacteria such as pneumococci or streptococci. The possibility is raised that the peroxidases of inflammatory cells and certain biologic fluids may affect tumor initiation or growth in vivo.     

Inhibition of endotoxin-induced activation of the coagulation and fibrinolytic pathways using a recombinant endotoxin-binding protein (rBPI23)

A recombinant endotoxin-neutralizing protein, rBPI23, was shown to partially prevent endotoxin-induced activation of the fibrinolytic and coagulation systems in experimental endotoxemia in humans. In a placebo- controlled, blinded crossover study, eight volunteers were challenged twice with an intravenous bolus injection of endotoxin (40 EU/kg of body weight) and concurrently received either rBPI23 (1 mg/kg) or placebo (human serum albumin, 0.2 mg/kg). rBPI23 treatment significantly lowered the endotoxin-induced fibrinolytic response, ie, reduced the release of tissue-type plasminogen activator, urokinase- type plasminogen activator, plasminogen activator inhibitor antigen, and complex formation of plasmin alpha 2-antiplasmin (P = .0078 for each). Plasminogen activator inhibitor activity was also reduced, but not significantly according to the Hochberg method (P = .0304). The endotoxin-induced activation of the procoagulant state as reflected by increase in F1 + 2 fragments and TAT complexes was blunted by rBPI23 infusion (P = .0391 [not significant according to the Hochberg method] and .0078, respectively). These results indicate that rBPI23 is capable of reducing both the activation of the fibrinolytic and the coagulation systems after low-dose endotoxin infusion in humans.     

How safe is diathermy in patients with cochlear implants?

INTRODUCTION

Cochlear implants are surgically inserted electrical devices that enable severely or profoundly deaf individuals to interpret sounds from their environment and communicate more effectively. As a result of their electrical nature, they are susceptible to electromagnetic interference and can be damaged by excessive electrical energy. Surgical diathermy is one source of such potentially damaging energy. The British Cochlear Implant Group guidelines advise that monopolar diathermy should not be used in the head and neck region in patients with cochlear implants and that bipolar diathermy should not be used within 2cm of the implant (http://www.bcig.org.uk/site/public/current/safety.htm).

METHODS

A questionnaire was provided to 36 surgeons working in different specialties in the head and neck region, inquiring as to their knowledge of the safety considerations when using diathermy in cochlear implant patients. Thirty-five surgeons provided responses.

RESULTS

Overall, 77% of the respondents were unaware of the existence of published guidelines. Even when given an option to seek advice, 11% erroneously felt it was safe to use monopolar diathermy above the clavicles with a cochlear implant in situ and 49% felt that there was no restriction on the use of bipolar diathermy.

CONCLUSIONS

There is a significant deficit in the knowledge of safe operating practice in the rapidly expanding population of patients with cochlear implants which threatens patient safety. Through this publication we aim to increase awareness of these guidelines among members of the surgical community and this paper is intended to act as a point of reference to link through to the published safety guidelines.