In situ dormancy of B lymphocytes programmed for an IgE antibody response and their sudden release from unresponsiveness under in vitro conditions

Priming of CBA/J mice with different doses of antigen has aprofound effect on the ratio of IgE versus IgG antibodies appearingupon Immunization. Repeated injections of minute doses induceIgG and high titers of IgE antibodies. Large doses elicit ahigh IgG but a very low IgE antibody titer. In order to studythe modalities for activation and inactivation of IgE-producingB cells, an in vitro culture system was established in whichspleen cells from animals primed with keyhole limpet hemocyaninwere re-stliulated with antigen. In contrast to the expectationfrom the in vivo situation, spleen cells from animals Immunizedwith large doses of antigen and virtually lacking IgE antibodiesproduce high amounts of IgE antibodies upon re-stimulation invitro. The titers in spleen cell cultures from mice primed withminute doses remain proportional to the response measured asserum antibodies. In accordance with the induction of high amountsof IgE antibodies in spleen cell cultures from mice primed withlarge doses, the frequency of IgE antibody-secreting cells wasraised drastically, 1000-fold. The in vitro response is a trueanamnestic response. The sudden appearance in high frequencyof IgE antibody-forming cells among spleen cells isolated fromprimed mice which have high IgG but virtually no IgE antibodytiters is as yet unexplained and the origin of the B memorycells has not yet been traced. The answer might be crucial forour understanding of the down-regulation of the IgE Immune responses.     

Pharmacodynamic Analysis of Analgesic Clinical Trials Using Empirical Methods

Data from analgesic clinical trials have characteristics such as ordered categorical longitudinal responses with repeated measures, delay of effect with respect to analgesic plasma concentration, and right-hand censoring of response due to remedication. In order to determine the concentration-effect relationship of such data, we propose convolving an empirical function for plasma concentration, in the form of broken lines which connect each pair of neighboring observations, with a monoexponential function, to generate effect site concentration Effect site concentration and time are used, simultaneously, as independent variables in the fit of the model for the logit of the probability of having a specific pain relief (PR) score at each time point pre-remedication, via maximum likelihood. Using corresponding effect site concentration, the probabilities of having specific PR scores post-remedication are predicted via the concentration-response relationship established. The overall (pre- and post-remedication) predictions and corresponding standard errors for the responses are then estimated. Inference of the PR scoring, using a posterior method, is proposed. An illustration using real data is used to demonstrate these methods.     

ARIMA模型在医院卫生消耗材料需求量预测中的应用

目的 阐述ARIMA模型拟合时间序列的方法和步骤,并将其应用于医院卫生消耗材料需求量的预测,为医院设备管理人员提供决策依据。方法 利用SAS软件系统,求解适宜的ARIMA模型,据所得误差评价预测效果。结果 通过对3种卫生消耗材料需求量的预测,相对误差在10％左右,预测效果较为可靠。结论 医院卫生消耗材料需求量的近期预测中引入时间序列的ARIMA模型分析方法,能够对实际工作产生积极的指导意义。     

Attitudes and Approaches of Influential Role Models in Clinical Education

The influence of a role model is a frequently cited factor in choosing a specialty choice among medical students, particularly primary care oriented students. While many studies have looked at role modeling from students' perspectives, very few have considered role modeling characteristics from the perspective of the role models. This study, using the principles of Bandura's social learning theory, determined and illuminated the characteristics and teaching methods associated with positive role modeling in clinical education from the perspective of the role model. A qualitative approach employing interviews and observations was used. Five themes emerged: the role models' approaches to teaching, their attitudes towards teaching and learning, their emphasis on clinical competence in their teaching, their roles external to their specific responsibilities, and their general affect. We found that role models were similar in their views of teaching and working with students. Also, their teaching characteristics were similar to the recommended approaches found in the literature and adhered to the principles of social learning theory. Role models were attentive to the needs of the students and tailored their teaching appropriately. They provided students with ample patient interaction so that students could apply their classroom knowledge. They also demonstrated how rewarding being an effective physician can be. This revised version was published online in June 2006 with corrections to the Cover Date.     

不同通气方式对机械通气引起急性肺损伤兔模型的影响

目的：通过表面活性物质缺乏的兔肺模型,评估传统通气模式（ｃｏｎｖｅｎｔｉｏｎａｌ ｍｅｃｈａｎｉｃａｌ ｖｅｎｔｉｌａｔｉｏｎ,ＣＭＶ）与允许性高碳酸血症加最佳ＰＥＥＰ（ｐｅｒｍｉｓｓｉｖｅ ｈｙｐｅｒｃａｐｎｉａａｓｓｏｃｉａｔｅｄ ｗｉｔｈｉｄｅａｌＰＥＥＰｖｅｎｔｉｌａｔｉｏｎ,ＰＨＹ＋ ＰＥＥＰｉ）的通气模式对肺损伤的影响,了解肿瘤坏死因子α（ｔｕｍｏｒ ｎｅｃｒｏｓｉｓｆａｃｔｏｒα,ＴＮＦα） 与机械通气引起肺损伤（ｖｅｎｔｉｌａｔｏｒｉｎｄｕｃｅｄｌｕｎｇｉｎｊｕｒｙ,ＶＩＬＩ） 的关系。方法：１２ 只成年兔,以反复肺灌洗法制备表面活性物质缺乏兔肺模型。以ＣＭＶ（Ｃ组） 或ＰＨＹ＋ ＰＥＥＰｉ （Ｐ 组） 通气４ ｈ 后,测定通气前、后的支气管肺泡灌洗液（ｂｒｏｎｃｈｏａｌｖｅｏｌａｒ ｌａｖａｇｅ ｆｌｕｉｄ,ＢＡＬＦ）中ＴＮＦα含量和白细胞分类计数,测定肺水量,进行动脉血气分析和病理检查。结果：ＣＭＶ 组表现为明显的低氧血症,ＢＡＬＦ中较多的中性粒细胞数,总肺水量及血管外肺水量明显增多,肺内病理改变为较明显透明膜形成及炎性细胞聚集;而ＰＨＹ＋ ＰＥＥＰｉ 组引起较少的上述病理、生理变化。且ＣＭＶ 组ＢＡＬ     

离子通道门控动力学研究

报道作者近期在离子通道动力学方面所作的研究工作。以膜片钳记录信号的自相关函数为基础,证实了离子通道记忆性的存在,并提出两状态非线性随机模型和镶嵌点过程模型,用于描述记忆性和门控动力学的特征,这样做可以克服Ｍａｒｋｏｖ模型和分形模型所遇到的３项困难,即状态不可辨认性、开关判定的主观性和时间间隔疏漏。另外,作者还提出了连续分组平均时间检测法,帮助确定Ｍａｒｋｏｖ模型中状态的个数,与多指数拟合法相比,此方法更直观和易于操作     

离子通道镶嵌点过程模型在K+通道研究中的应用

目的：用作者提出的离子通道镶嵌点过程模型拟合海马锥体细胞钾离子单通道记录数据分析１７β雌二醇的效应。方法：用协方差密度度量通道记忆,从３个方面做拟合优度检验。结果：该模型与观察资料拟合效果良好;１７β雌二醇能改变海马锥体细胞钾离子单通道的记忆;１７β雌二醇对关闭的影响比对开放的影响大,从而表现为对通道具有抑制作用：浓度为１０ｎｍｏｌ／Ｌ组的１７β雌二醇对通道记忆的影响比对浓度为０１ｎｍｏｌ／Ｌ组的大。结论：Ｍａｒｋｏｖ模型的常规分析只能得到１７β雌二醇对海马锥体细胞钾离子单通道具有抑制作用,而用本模型分析能得到更多通道的信息     

肉毒碱治疗TPN大鼠肝脂肪变性的研究

目的 探讨在全胃肠外营养（ＴＰＮ）中补充肉毒碱减轻肝脂肪变性的作用。方法 １８只正常Ｗｉｓｔａｒ大鼠和１９只肝硬化Ｗｉｓｔａｒ大鼠分别随机分为６组,Ａ１组、Ａ２组,自由进食和进水（各６只）;Ｂ１组、Ｂ２组,ＴＰＮ（分别６只、７只）;Ｃ１组、 ,ＴＰＮ加肉毒碱（各６只）。各组实验结束后测肝功能,肝脂肪及行肝脏的组织学检查。结果 ＴＰＮ组肝内脂肪显著２,ＴＰＮ＋肉毒碱组肝内脂肪明显减少。结论 在ＴＰＮ     

Evaluating problem-based learning in a multilingual student population

OBJECTIVES: The University of Natal Medical School in South Africa provides training for a student body composed of two groups: one with English as a first language and the other with an African language as a first language and English as the second. A new methodology was developed to evaluate an innovative course using modified problem-based learning techniques in this heterogeneous environment. DESIGN: The learning model proposed required achieving a balance of three components: content, enquiry/learning process and social interaction/group process. A multidimensional system, felt to be consistent with this educational philosophy, was developed using seven different quantitative and qualitative techniques. SETTING: The University of Natal Medical School. SUBJECTS: First-year multilingual medical students. RESULTS: The results revealed that social interaction was highly successful in reducing barriers between the student groups and between students and facilitators. However, the emphasis on group participation may have overshadowed the enquiry process, leading to superficial discussions of problems and feelings of repetitiveness. During the course students and facilitators expressed concern that the innovative assessments used did not assess the course content adequately. While the group presentations and projects were useful exercises for consolidation and group interaction, they did not enable facilitators to identify struggling students. CONCLUSIONS: The outcome of the evaluation stressed the need of achieving an appropriate balance both in the curriculum and assessments of the three components of the learning model, particularly in a setting where student backgrounds and language ability differ. Multidimensional methodology is needed for effective evaluation that promotes critical reflection.     

Research utilization models: frameworks for implementing evidence-based occupational therapy practice

Evidence-based practice is an important step in the professional evolution of occupational therapy and also provides the means for state-of-the-art innovative clinical service for clients. An essential step in incorporating innovations and developments into clinical practice is through research utilization. Nine models of research utilization developed in the literature are reviewed and critiqued. These are: (1) the Conduct and Utilization of Research in Nursing (CURN) Project; (2) the Stetler-Marram Model; (3) the University of North Carolina Approach; (4) the Innovation Diffusion Process Model; (5) Killeen's Matrix of Research Activity; (6) the Iowa Model of Research In Practice; (7) the Western Interstate Commission for Higher Education In Nursing Project; (8) the Nursing Child Assessment Satellite Training Project; and (9) the Linkage Model. Research utilization models provide a framework for collaboration and the necessary conditions for research utilization activities to be successful. Copyright © 1999 Whurr Publishers Ltd.