Abstract

Immunoglobulin Gene Conversion and Somatic Hypermutation:
Regulation, Evolution and Biotechnology

Hiroshi Arakawa

Immunoglobulin (Ig) genes of chicken are diversified by segmental gene conversion using pseudo V genes as donors. Our lab has studied molecular mechanisms of post V(D)J diversification using chicken B cell line DT40, which has gene conversion activity and high ratios of targeted integration. We have shown that activation-induced cytidine deaminase (AID), the key regulator of class switch recombination and somatic hypermutation, is required for gene conversion, and it meant that all the three post V (D) J re-modeling systems depend on AID. Interestingly, knockout of the pseudo gene donors changes Ig gene diversification system of DT40 from gene conversion to somatic hypermutation, indicating that these two different diversification systems are related and competing pathways with each other. In this seminar I will review recent topics of us and other labs on gene conversion and hypermutation: especially about their mechanism and regulation, evolution of Ig gene diversification system, and application of Ig gene diversification system for biotechnology.

In Situ Gene Therapy for Prostate Cancer;
Kitasato Experience

Shiro Baba

The incidence of prostate cancer has dramatically increased worldwide in the past decade, with mortality rates also increasing in many countries. Once prostate cancer is diagnosed, it is important to rapidly begin a treatment regimen that is either potentially curative or impedes disease progression. When the disease is confined to the prostate, it can be cured by radical prostatectomy or irradiation therapy. However, there are no curative therapies for locally advanced, recurrent, or metastatic diseases. Clearly, development of new therapies are required for these patients. Gene therapy may provide additional therapeutic options with the potential to clinically affect both high-risk localized and metastatic disease. Virus-mediated transduction of the herpes simplex virus thymidine kinase (HSV-tk) gene transfer, followed by a course of the prodrug ganciclovir (GCV), so-called suicide gene therapy, has been demonstrated by several investigators. Currently, we have started the neoadjuvant HSV-tk gene therapy at our institution and it has demonstrated the potential efficacy in men with a high-risk prostate cancer. A reduction in serum PSA was observed immediately after vector injection and GCV infusion. The mean reduction was 28.5% (range; from 24.8 to 30.8%). The percentage of activated T cells (CD8+DR+ and CD4+DR+) in peripheral blood transiently increased after HSV-tk + GCV treatment. Furthermore, these cells exhibited interesting increase at three weeks after the treatment and post radical prostatectomy. The biggest change likely to occur in prostate cancer therapy over the next 5 years is the adoption of novel therapies in combination with conventional therapies. The relatively slow growth of prostate cancer makes the combined use of in situ gene therapy with surgery or irradiation therapy as a neoadjuvant⁄adjuvant approach a reasonable option. In situ gene therapy for prostate cancer may promote antimetastatic effect through the generation of immune cell-mediated cytotoxic activities that affect not only the primary tumor but also metastatic lesions. In situ gene therapy may work as an “active vaccine.”

Ca Regulation in the Heart: In and out of Control

David Eisner

Most of the calcium that activates contraction in the ventricle comes from the sarcoplasmic reticulum (SR) and is released by the process of calcium induced calcium release (CICR). I will initially consider the mechanisms involved in regulating SR Ca content. We find a simple feedback mechanism in which an increase of SR Ca results in a larger systolic Ca transient which, in turn, increases Ca efflux from the cell thereby decreasing SR Ca content. If SR Ca content is increased above a threshold value then propagating waves of CICR which produce arrhythmogenic delayed afterdepolarizations (DADs) are observed. This may also occur when SR Ca content is not elevated. One example is in the presence of mutations of the RyR which can cause catecholaminergic polymorphic ventricular tachycardia (CPVT). Here ventricular arrhythmias occur when catecholamine levels are increased during exercise and other stresses. This arises because the mutated RyRs leak Ca during diastole. We have examined whether increasing the RyR leak per se produces diastolic Ca waves. When low concentrations of caffeine are applied to increase RyR opening Ca waves are only seen for a few seconds and then disappear due to the accompanying decrease of SR Ca. If, however, a β-adrenergic agonist is first applied then caffeine produces waves in the steady state and we attribute this to the increase of SR Ca content due to the β agonist. This explains why the patients with mutated RyRs develop arrhythmias during exercise.

Learning Experiences and Assessment in the First Two Years of the Medical Course at King's College London

Despina K. Papachristodoulou

The medical curriculum at King's College School of Medicine is a five year course. An Extended Programme (6 years) and a Graduate Entry programme (4 years) are also available. The first two years of the curriculum comprise phases one and two. The curriculum consists of ‘core ‘common to all students and student -selected components (Students undertake 3 in the 2 years). Phase one lasts 12 weeks where students learn the principles of tissue and organ structure and function. They are also introduced to the practice of Medicine (concepts of health, communication, ethics, inter-professional education, medicine in the community. Phase 2 consists of 36 weekly clinical scenarios placing basic medical science in a clinical context. Phase 2 covers cardiovascular, respiratory, gastrointestinal, renal and musculoskeletal systems, nutrition, endocrinology, head and neck anatomy, neuroscience, genetics and infections. Teaching continues in primary care and in the hospitals and includes basic and advanced life support. Learning experiences include lectures, tutorials, practical classes, dissection and prosection, communication skills, e learning, student- led sessions and primary care and hospital visits. Assessment consists of in course assessment (ICA, e.g. presentations, tests and essays) and end-of-year examinations which consist of written papers and an Objective Structured Clinical Examination (OSCE) at the end of year 2. The main strengths of the programme include the scenario format of learning and the practice of Medicine early on. The difficulties arise mainly from the large numbers of students (420 per year).

eLearning & eResources in Medical Education

David Byrne

The use of computers and the internet to deliver education is not a new idea. Educators have been using computers to teach ever since the mass market affordable computer was first introduced. It is only in recent years, since the introduction of the world wide web in the early 1990s, that eLearning has been highly developed as a serious educational tool to deliver teaching and learning opportunities across distance and with no restrictions on time or location. eLearning has many definitions and means different things to different people. Electronic learning resources can be used to provide supplementary training and educational resources; as a replacement for parts of, or entire courses or as supplementary self-directed learning opportunities. At King′s College London School of Medicine we use a mixture of all of these approaches in our curriculum. Across the UK there are also many government funded resources providing advice and resources for Higher Education Institutions. Within the healthcare sector, the National Health Service (NHS) which provides healthcare for the UK has developed a wide range of information portals for patients and eLearning resources for Healthcare staff across a wide range of specialities. eLearning can work and be successfully embedded within a medical curriculum but this does take a lot of initial planning, work and investment (both financially and staff commitment) to really make it useful and educationally acceptable to both staff and students.

Getting Started in Medical Education Research

David A. Cook

Education research and scholarship are critically important in extending our ability to teach and assess effectively. This article provides guidance for planning and executing a scholarly project in medical education. Boyer described four classes of scholarship - discovery, integration, application, and teaching - and each of these classes is important in the field of medical education. Those considering a scholarly project in medical education should consider the following tips, learned from personal experience and supported by literature: 1) get training, 2) find a mentor, 3) ask important questions, 4) start small and grow, 5) aim high, 6) don′t wait for the perfect study 7) plan for adequate time and other resources, 8) pay attention to ethical issues, 9) network with others in the field, and 10) recognize that this is hard work. It is essential to plan projects (in advance, if possible) using the three-step approach of identifying the scholarly question, using appropriate methods, and selecting appropriate outcomes.