Oral tolerance in EAE: reversal of tolerance by T helper cell cytokines

Oral administration of myelin basic protein (MBP) inhibits clinical and histopathological manifestations of experimental autoimmune encephalomyelitis (EAE), but only partially reduces serum anti-MBP antibody titers. We report here that orally administered MBP alters the isotypic distribution of anti-MBP antibody-forming cells (AFC) among various lymphoid tissues, with the most profound differences seen in mucosal tissues. We observed an isotype-selective reduction in anti-MBP IgA but not IgM AFC frequencies in Peyer's patches. The anti-MBP IgA AFC frequencies could be reconstituted by addition of interleukin 4 (IL-4) and interleukin 5 (IL-5). The cytokines did not appear to generate de novo responses since no increases in anti-MBP IgA AFC frequencies were observed in control cultures. These results indicate that decreased antibody production, as a result of oral antigen administration, can be reversed by exposure to the appropriate cytokines.     

Teaching of medical ethics

Teaching medical ethics in Manchester within the introductory course of obstetrics and gynaecology is a joint activity with the Centre for Social Ethics and Policy. This interdisciplinary teaching has evolved through lecture sessions with small-group discussions dealing with topics of interest in human reproduction. The small-group discussion have been replaced by an open debate conducted by the students. Their own involvement and participation and an exposure to the disciplines of the humanities has broadened their approach to different ways of problem-solving of these real issues.     

Endoscopic sealing of infected bronchus stump fistulae with fibrin following lung resections

Summary Bronchus stump insufficiency following lung resection, with an average incidence of 4%, is a serious complication which carries a mortality of up to 90%. Operative transthoracic approaches have been largely unsatisfactory because of the high operative risk and rapidly spreading infection. In an experimental study on 18 pigs, endoscopic occlusion of infected bronchus stump fistulae was achieved with fibrin sealant (1 ml, 500 units/ml thrombin, 3500 units/ml aprotinin) applied via a flexible bronchoscope. During autopsy, all bronchus stump fistulae were found to have healed after the second postoperative week. Transitory local abscesses of the pleura could be prevented by high-dose systemic antibiotic therapy for 5 postoperative days but not by antibiotics added to the fibrin sealant. This endoscopic method has already been performed successfully in 3 clinical cases; additional sclerotherapy with (2–3 ml Ethoxysclerol applied around the fistula orifice was carried out before fibrin sealing to stimulate fibrosis. Endoscopic controls demonstrated fistula closure by granulation tissue after 2 weeks. This procedure could become the method of choice for infected postoperative fistulae of the bronchus stump and should be attempted in any case before operative approaches are considered.     

Effects of simplifying choice tasks on estimates of taste heterogeneity in stated-choice surveys

Researchers usually employ orthogonal arrays or D-optimal designs with little or no attribute overlap in stated-choice surveys. The challenge is to balance statistical efficiency and respondent burden to minimize the overall error in the survey responses. This study examined whether simplifying the choice task, by using a design with more overlap, provides advantages over standard minimum-overlap methods. We administered two designs for eliciting HIV test preferences to split samples. Surveys were undertaken at four HIV testing locations in San Francisco, California. Personal characteristics had different effects on willingness to pay for the two treatments, and gains in statistical efficiency in the minimal-overlap version more than compensated for possible imprecision from increased measurement error.     

活体顺序性荧光标记技术在实验性骨折愈合研究中的应用

目的介绍实验性骨折愈合研究中活体顺序性荧光标记的技术与方法。方法以成年兔胫骨骨折外固定为模型，术后分别以Tetracydin(TC，黄色，25mg／kg)、Calcein(CG，绿色，10mg／kg)、Xylenal(XO，桔色，90mg／kg)、Alizarin—complen(AE，红色，30mg／kg)四种荧光染料于兔颈部皮下定期注射；并于术后第3、6、12及24周活杀动物，解剖出胫骨，梯度乙醇脱水、脱脂，甲基丙烯酸甲脂包埋，切片厚度40～100μm，打磨，荧光显微镜下观察、摄像；同时通过组织学观察、X线摄片了解骨愈合速度与质量。结果顺序性荧光标记显示，加压组中钙化的内、外骨痴均于术后第2周出现于截骨处的远、近断端，但尚未形成骨性连接。亦无骨皮质的改建。外骨痴增生停止于术后12周，且骨皮质的改建至12周已渐减少．至术后24周已基本完成；对照组：内骨痴于术后第3周出现于截骨处远、近断端，无钙化的外骨痴形成，亦无骨皮质的改建；外骨痂增生停止于术后12周，骨皮质改建至24周尚未完成，其结果与组织学观察、X线摄片具有一致性。结论活体顺序性荧光标记技术可以从细胞水平判断新骨的开始时间、骨生长速度及生长方向，并能节约实验动物数量，是实验性骨折愈合研究中较为理想的研究手段。     

Self-directed learning in anatomy: incorporation of case-based studies into a conventional medical curriculum

This paper reports an attempt to develop self-directed learning skills in second-year medical students by introducing case-based projects into the gross anatomy course at a long-established medical school. The programme and students' responses to a questionnaire completed at the end of the year are presented. Information on the various resources used by students to find information is given. The performance of students in the case-based components of the course has been evaluated and also in the more traditional end-of-year written examination. The data confirm that students have recognized that the projects were about obtaining a deeper understanding of the anatomy, and the programme appears to have promoted the use and study of library texts.     

Undergraduate medical education in obstetrics and gynaecology in the USA and Canada, 1985

Many factors have led to a movement from the emphasis of the 1960s and 1970s on departmental expansion towards an emphasis on cost-effective undergraduate medical education emphasizing the 'art' as well as the 'science' of medicine. In January 1985 a questionnaire was sent under the auspices of the Undergraduate Education Committee of the Association of Professors of Obstetrics and Gynecology to all chairmen of departments of obstetrics and gynecology in the USA and Canada seeking their opinions about these trends and information about the educational programmes in their departments. The information from this study indicates that the chairmen are aware of and responding to this new direction in medical education. A stabilization of teaching staff and clerkship sizes and the emphasis on clinical as well as cognitive evaluation, despite recognition of the cost of the former, shows active interventions towards these ends. An emphasis on education in 'basic' as compared to 'subspecialty' areas which is independent of the subspecialty of the academic chairman also supports this trend.     

Teaching school health to undergraduate medical students

This paper describes a teaching programme for final- (sixth-) year undergraduate medical students during their 10-week term in child health. Students attend schools on two occasions and are actively involved in the physical, educational and emotional assessment of children. The advantages of the programme include active participation by the students, contact with children in a less threatening environment, learning new skills in the assessment of children, and knowledge of common screening procedures. Student evaluation of the programme has been positive.     

三个统一:21世纪中医学发展取向的思考

21世纪中医学的发展，面临着理顺民族性表述方式与国际性科学内涵关系的问题，因此必须辩证地把握结构与机能、实证科学手段与人文精神、过程与结果之间的谐调统一，这样既符合中医学术体系特征，又能与当代生命科学研究保持一致。     

Magnetic resonance imaging of antibody-mediated demyelinating experimental allergic encephalomyelitis

Two models of demyelinating experimental allergic encephalomyelitis (EAE) were studied on Lewis rats in whom the disease was induced by injections of either (i) lentil-lectine binding myelin glycoproteins plus myelin basic protein (MBP)-specific T cells (36 rats), or (ii) myelin/oligodendrocyte glycoprotein-specific monoclonal antibody plus MBP-specific T cells (16 rats). In our 24 control rats, 20 received MBP-specific T cells only, and four received myelin glycoproteins plus purified protein derivative-specific T cells. The extent of the resulting blood-brain barrier (BBB) permeability, vasogenic oedema and/or demyelination was assessed in vivo using magnetic resonance imaging (MRI) techniques. The results show that in both demyelinating EAE models the disease appeared more quickly, progressed very rapidly and was more severe than when induced with a similar number of MBP-specific T cells alone. Almost all animals developed hypercute EAE, with a very high mortality rate. MRI showed a very intense BBB breakdown and vasogenic oedema in all the normally ‘leaky’ areas of the central nervous system, and focal lesions corresponding to plaque formation in the brain stem or spinal cord near the ‘leaky’ areas. During the 40-day observation period, the rare survivors of this hyperacute form of EAE presented a chronic form of EAE with serious sequelae. Our results demonstrate that the synergistic effect observed between MBP-specific T cells and antibodies to myelin glycoproteins, especially to myelin/oligodendrocyte glycoprotein, does not only induced demyelinating lesions and chronic clinical signs, but is further responsible, via the normally ‘leaky areas’, for the fatal increase of the BBB breakdown and vasogenic oedema of which there are ample acute clinical signs.