Newsletter No. 410

2 No. 410, 4.1.2013 R ichard Dawkins thinks that Darwin is the greatest mind that ever lived. He also admits that he feels the same sense of reverential hush towards R.A. Fishe r, founder of modern statistics. The marriage of statistical theories and methods and the biological sciences have brought us the modern discipline of biostatistics. However, neither the impact of Fisher nor that of biostatistics is always duly recognized. According to Prof. Benny Zee of the Jockey Club School of Public Health and Primary Care, CUHK, biostatistics encompasses the design of biological experiments, especially in medicine and agriculture, on the collection, summarization, and analysis of data from those studies, and their interpretation and inference of the results. Biostatisticians are men of two trades, one in numbers and the other in the field of application. They use statistical reasonings, models and methods to re-formulate the problems into quantifiable functions and optimize the results for solutions and decisions. It is because of their ability to straddle and expand the boundary of a larger terrain of enquiry that they are often in a better position to act as problem-solvers and play a policy and advisory role. Common applications of biostatistical methods include quality control in industrial engineering, genetics in biology, clinical research methods in medicine, and actuarial and life tables in healthcare. The British statistician, Sir David Cox , has made many important contributions, of which the best known is perhaps the proportional hazards model, which is widely used in the analysis of survival data. An example is survival times in medical research that can be related to information about the patients such as age, diet or exposure to certain substances. Professor Zee had extensive experience in clinical trial methodology for drug development in North America before he came back to Hong Kong in 2001 to help build the discipline of biostatistics at CUHK. He would apply statistical reasonings to the testing and performance of new drugs to determine the optimal conditions under which a new drug was effective or otherwise, with the aim to enhancing the screening efficiency of new drugs. Such work obviously has immense impact on the pharmaceutical industry and the welfare of patients. His most recent innovation is in developing an algorithm for an automatic diagnostic system for cerebral vessel conditions and evaluation of the risk of stroke. This grew out of a collaboration with Dr. Jack Lee , a biostatistician with expertise in finance and bioinformatics, and Dr. Li Qing , an ophthalmologist and a PhD student of his who set out to identify vascular diseases before stroke happens. Up to 80% of all diabetics of over 10 years would develop diabetic retinopathy (DR) which is damage to the retina caused by diabetes mellitus, with a concomitant higher chance of suffering stroke at a later stage. DR screening has become a standard procedure in diabetic care but its effectiveness is hampered by several factors: not enough specialists to administer the screening, human variability in diagnosis, long waiting time for the result, and high cost. To address these issues, the team had to find a methodology to turn the analogue images of the retina into quantifiable and analyzable data. The finding of a pattern out of seemingly chaotic information was what Professor Zee had learned from his teacher at the University of Pittsburgh, Prof. C.R. Rao . According to Professor Zee, the first difficulty encountered in the process was the location of the optic disc (the spot where the light-sensitive ganglion cell axons leave the eye to form the optic nerve to the brain, also known as the physiological blind spot). Although methods of locating it already existed, his team developed a new method that best fit their purpose. A greater hurdle, however, laid in the detection of new vessels in the eye whose growth is a sure sign of havoc to come. As new blood vessels are short, irregular and squiggly, the determination of their existence and state of growth eluded all existent automatized technology. Applying the skills of a biostatistician in pattern recognition and quantification, the team was able to devise an algorithm which reads pixel by pixel the retinal images and analyze such pixels to come up with measurements on exudates, haemorrhages, new vessels and finally achieve the overall evaluation of retinopathy. Standard retinal images can be transmitted through the Internet to a server installed with the algorithm and the result or report is available within a short period of time. The new method is non-invasive and will substantially reduce bias due to human perception as well as cost and time. Initial tests have confirmed its dependability and high accuracy rates. Next, Professor Zee intends to expand the technology and apply it to both diabetes and non-diabetes patients for the early detection of strokes. The eye is the window to the soul, and so is it to sickness. Usually another human eye is required to judge if any hazard is forthcoming—that is the role of the traditional physician. Professor Zee and his team have devised an algorithm that does the job of the expert eye, so that the tool can benefit a wider population of individuals and make bigger impact on health care in general. 灵魂之窗窥探隐患 A Clearer Window to Health Hazards 徐仲鍈教授 Prof. Benny Zee 徐仲 鍈 教授1987年获美国匹兹堡大学生物统计学博士学位,随后加入加拿 大国立癌症研究所临床试验组任高级生物统计员,并任加拿大女王大学公共 卫生及流行病学系及数学和统计系教授。徐教授现为中大赛马会公共卫生及 基层医疗学院教授,同时为学院生物统计学学部主任。 Prof. Benny Zee obtained his PhD in Biostatistics from the University of Pittsburgh in 1987. He then joined the National Cancer Institute of Canada Clinical Trials Group as senior biostatistician, and Queen’s University as a faculty member in its Department of Community Health and Epidemiology and the Department of Mathematics and Statistics. He is a professor at the CUHK Jockey Club School of Public Health and Primary Care heading the Division of Biostatistics. (左起)徐仲鍈教授、李作为博士及莫仲棠教授展示全自动化视网膜图像分析系统 (From left) Prof. Benny Zee, Dr. Jack Lee and Prof. Vincent Mok with the automatic retinal image analysis system 理 查德·道金斯 推崇达尔文是古往今来头脑最好的人, 而连带对其理论继承者、现代统计学奠基者 费雪 ,同 样敬重有加。统计学的理论和方法,跟生物科学结合之后, 衍生了现代生物统计学。可是,不管费雪的成就还是生物统 计学的影响,能获大众认识者寥寥无几。 据赛马会公共卫生及基层医疗学院 徐仲 鍈 教授表示,生物统 计学涵盖生物实验的设计,尤其是医学和农业,并包括搜集、 总结和分析研究数据,以及解读和推论结果。生物统计学家 精通数字与应用,他们会以统计学的思路、模型和方法,把问 题分拆成可量化的函数,以寻找最佳的答案和计策。生物统 计学家擅于跨越界别,能够从更宽广的层面探讨问题,是故 更适宜担当排难解疑,或制定政策和谘询的角色。 生物统计学方法常应用于几方面∶检定工业工程质量、检测 遗传基因、临床医学研究,以及编制人口生命表。英国统计 学家 戴维·科克斯 爵士最为人熟悉的贡献是他所创制的比 例风险模型,广泛应用于分析存活数据,按照病人的年纪、 饮食习惯或接触某些有害物质的情况,推算其存活时间。 徐教授在2001年加入中大,协助成立生物统计学学部前,在 北美洲专职测试新药,验证疗效,从而找出一种新药在什么 条件下能发挥最佳药效,藉此提高筛检效率。有关工作对制 药行业和病人有莫大裨益。 他的最新创意成果是开发出一套演算法,供评估脑血管情 况和中风风险的自动诊断系统之用。与徐教授共同研发的, 包括专长于财经和生物资讯的生物统计学家 李作为 博士,以 及徐教授指导的博士研究生、致力透过检查血管病变防范中 风的眼科医生 李青 。 患糖尿病达十年以上的人,超过八成会有糖尿病视网膜病 变,即俗称「糖尿上眼」,到后期中风机会亦相应增加。现 时,糖尿病视网膜病变筛查属于常规检查,但成效受几方面 影响∶专科人手不足,不同医生判断有差异,等候结果时间太 长,以及成本高昂。 为此,研究团队戮力寻找方法,把视网膜的模拟影像转换成 可量化及可分析的数据。从看似杂乱无章的资料中找出脉 络,正是徐教授早年在匹兹堡大学 拉奥 教授指导下的训练。 他遇到的第一个难题,是如何找出视神经盘(俗称「盲点」, 感光的神经节细胞轴突汇集成视神经,并由该处离开眼球 连接大脑)的准确位置。现成办法是有的,但团队也研发了 一套更切合本身需要的方法。至于最大困难,莫过于侦测眼 内增生的血管,它们一旦出现,就是大祸逼近的先兆。增生 的血管都是既短且弯,呈不规则形状,要发现并查出它们的 生长情况并不容易。团队施展生物统计学家最擅长的模式 识别和量化工夫,设计了一套运算法,把视网膜图像分拆为 像素单位,逐点分析,以量度眼底渗液、出血和血管增生情 况,从而得出视网膜病变的整体评估结果。 一般视网膜图像可以透过互联网,传送至内置演算法的伺 服器,不一会即可取得检查报告。这种崭新的非入侵检查方 法,不受体检人员的主观影响,既省钱又省时。初步测试证 实可靠,而且准确度高。下一步,徐教授将会应用到糖尿及 非糖尿病人身上,及早防范中风。 眼睛是灵魂之窗,也是健康的晴雨表。一直以来,要判断是 否有隐患,靠的是医生的一双眼。徐教授团队研发的检测 法,摇身一变为医学专家的慧眼,让广大市民受惠,对提升 本地整体医疗水平有极大贡献。 正常视网膜 Normal 糖尿病视网膜病变 Diabetic retinopathy 撷取视网膜影像 Retina image taking 筛查技术 Our screening technology 糖尿病视网膜病变分析报告 DR analysis report 边注边读 Marginalia 「跨学科」这个词听得多了,但究竟怎样才能做到「跨学 科」,却鲜见实例。今期「洞明集」介绍一门由数字与人体 科学交叉孕育出的学问。 徐仲 鍈 教授告诉我们,生物统计 学的历史远较一般人所想的悠久,影响也较一般人所知的 密切,是最博大而影响广泛的知识合体。 中大的学生和职员可能更为熟悉校园内的另一种「混合」, 就是大学游泳池旁的合作社混合多款草药和茶叶炮制的 特色小吃。不过最令人回味的除了在热腾腾的卤汁中浸泡 而成的茶叶蛋外,还有这家社会企业散发的人情味,这你可 在「舌尖上的中大」感受得到。 每个地方都有自己的独特性格,有的更自有气派。唐宁街 10号不单是住址,更是英国政府的中枢;美国白宫的椭圆 形办公室亦复如是。在中大,祖尧堂也有相若地位。这个 音响设备先进的会场,是举行重要会议、研讨会和典礼的 地方,置身其中,可隐隐感受到四壁回响过来的大学使命。 多年下来,墙上所挂的历任校监、校董会主席和校长的 肖像随岁月而增加,但你可知道,1971年刚启用时,这里 所挂的,就只得 关祖尧 爵士的肖像吗?请看「昔与今」。 We often hear the word interdisciplinary but rarely see an example of how it works. The ‘In Plain View’ article in this issue brings you a vivid example of the cross- fertilization of ideas from the science of numbers and the science of the human body. Biostatistics, as Prof. Benny Zee explains, has an older history and a closer impact than most people would think. It is fusion of the most sophisticated and impactful kind. Students and staff are perhaps more familiar with fusion of another kind on campus. Sundry herbs and tea leaves go into the preparation of one of the most popular homemade specialties of the small cooperative store by the poolside. What is so appetizing is not only the tea eggs simmering in the tea-coloured marinade but also the friendliness and warmth exuded from this campus social enterprise, as you will find out in ‘Mouth-watering Morsels’. Places have characters. Some are even dignified. 10 Downing Street is not only a home address but also the nerve centre of the British government. So is the Oval Office to the White House. At CUHK, Cho Yiu Hall plays a similar role. Important meetings, conferences and ceremonies are held in this premium venue with sophisticated acoustics. One could almost feel the University missions resounding off its paneled walls. Over the years, more portraits of Chancellors, Council Chairmen and Vice-Chancellors adorn its walls. But do you know it started out with only one, that of Sir Kwan Cho-yiu , in 1971? Check out ‘Then vs Now’. ———————■■■——————— 目录 Contents 洞明集 In Plain View 2 让非形式学习一目了然 3 A Systematic Presentation of Non-formal Education 校园消息 Campus News 4 昔与今 Then vs Now 5 宣布事项 Announcements 6 舌尖上的中大 Mouth-watering Morsels 6 人事动态 Ins and Outs 7 古明达如是说 Thus Spake Shekhar Kumta 8