Newsletter No. 528

根據世衞資料，現在全球約有五千萬名認知障礙症患者，每年卻有一千萬宗新增病例，估 計到2050年，全球患者達1.5億人。垂暮之年，神情舉止像小孩，面對此症，莫非真是束手  無策？ 在長者中，認知障礙症有三大成因，包括阿茲海默症、血管性認知障礙症，以及混合型障礙 症。血管性認知障礙症的患者常因腦細血管收窄栓塞而損害腦部，慢慢蠶食認知能力。若 是中風，腦部頃刻受損，認知能力便會即時衰退。中大莫慶堯醫學教授及醫學院內科及藥 物治療學系腦神經科主任 莫仲棠 說：「半數以上患者是混合型，他們既患上阿茲海默症，同 時患上腦血管疾病。」其他罕有原因包括酗酒或缺乏維他命B12等，後者可能因為食肉或魚 太少。 症類不同，病徵迥異。阿茲海默症患者的短期記憶衰退，例如有病人血壓過低，原來他忘 記已經服食了血壓藥，結果多番服藥。血管性認知障礙症患者則反應遲緩，不能兼顧多項 事務，又例如同枱食飯，患者不能與多人同時對答。 有研究指出，教育水平愈高，認知儲備愈豐富，即使不幸出現阿茲海默症或腦血管病變，其 認知能力受損程度也較輕微，情形就像注射了流感疫苗，即使日後遇上流感，亦未必有病 發的可能。莫教授說：「終身學習就是一種保護。」另外，積極參與社交活動，保持心境開 朗，勤做運動及管理心腦血管疾病的風險，如三高，都可減低患病風險。 「預防」已經成為對抗認知障礙症的新戰略，有初步研究顯示，若透過正電子掃描偵察到 澱粉狀蛋白，可於患者未出現嚴重症狀前，提早介入治療，用藥抑制，便有可能減慢病情惡 化。澱粉狀蛋白斑塊是阿茲海默症患者腦部常積聚的不正常蛋白。只要就各項風險因素提 早對症下藥，我們就有望避過返「腦」還童。 According to WHO, there are around 50 million dementia patients worldwide and nearly 10 million new cases every year. The total number is projected to reach 150 million in 2050. A return to childlike behaviour in one’s twilight years is fraught with difficulties if not dangers. Are we at our wits’ end in face of this irreversible cognitive impairment? Among the elderly, there are three common causes of cognitive impairment, or dementia as is commonly known: Alzheimer’s disease, vascular cognitive impairment, and a combination of the two (i.e., mixed dementia). Vascular cognitive impairment is commonly due to the narrowing and clogging of cerebral small blood vessels resulting in gradual deterioration of cognitive ability. In case of stroke, the patient’s cognitive abilities will drop abruptly. Prof. Vincent Mok , Mok Hing Yiu Professor of Medicine and Chief of Neurology, said, ‘But the majority of dementia cases, over 50 per cent, are caused by a combination of Alzheimer’s disease and cerebrovascular diseases.’ Other less common causes include alcoholism, or vitamin B12 deficiency. The latter can be due to inadequate meat or fish intake. The initial symptoms may vary with the cause of dementia. Alzheimer’s patients may have short-term memory loss. For example, an Alzheimer’s patient may keep taking anti-hypertensive drugs because she has forgotten she had already taken it, leading to hypotension. A patient with vascular cognitive impairment may be slow in responding to questions. Multitasking takes some struggling and the patient may find it hard to keep up the conversations with several members at dinner table. Studies point out that education could build up one’s cognitive reserve and protect the brain from developing cognitive impairment. Highly educated people suffer from milder cognitive impairment even if they develop Alzheimer’s and vascular pathologies inside their brains. The effect of education against dementia is like that of vaccination against flu. ‘Lifelong learning is a kind of protection,’ said Professor Mok. Being socially active, maintaining a positive attitude, regular physical exercise, management of one’s vascular risk factors (e.g., blood pressure, glucose and lipids) also help to reduce the risk of dementia. Prevention has become the new strategy in tackling dementia. For Alzheimer’s disease, some studies showed that anti-amyloid treatment may slow cognitive decline if it is applied at the stage when symptoms are only mild. Amyloid plaque is an abnormal protein associated with Alzheimer’s disease. Identifying risk factors of dementia early and taking corresponding measures could prevent dementia and brain degeneration. M. Mak 如何預防腦還童？ The Battle against Brain Degeneration 雅 共 賞 / ART iculation 醫醫筆寫/ D octors ’ N otes 點紙成金 Turning Paper into Gold 2018香港新鈔票系列開始逐步推出市場，你開始使用這些背面有着直向設計的特別紙幣了 嗎？無論對其主打香港情懷的圖像設計評價如何，新鈔作為當代印刷科技結晶這一點相信 是毋庸置疑的。在使用這些最新科技的時候，你又有否想過它的歷史淵源呢？ 不說不知道，中國其實是世界上最早使用紙幣的國家。因為金屬貨幣太笨重，不便遠程㩦 帶，北宋初年即已出現正式的紙幣—交子。元初承金、宋後期之弊，幣制紊亂，元世祖忽 必烈於是制定法律，設立機構，統一紙幣制度。他在自立為汗的中統元年（1260）印造了  「中統元寶交鈔」，後來在至元二十四年（1287）又發行了「至元通行寶鈔」。從當時「至 元」兌「中統」五比一的比率，我們可以看到「中統元寶交鈔」在二十七年間貶值的情況。 我們現在用的港元紙幣有六種面額，但原來「至元通行寶鈔」有十一種之多！它們分別是： 二貫、一貫、五百文、三百文、二百文、一百文、五十文、三十文、二十文、十文和五文，以二貫面 額最大。文物館藏品中有兩套「至元通行寶鈔」的印鈔工具，面值分別是五百文和二百文， 整套工具包括大、小鈔版及印章二套六件，二套形制、格式基本相同。因「五百文」鈔版文 字漫漶不清，而「二百文」鈔版文字較清楚，故以之為例作說明。 大鈔版為長方形，擡頭橫行楷書「至元通行寶鈔」六字，被一對內向對稱寶珠火焰紋夾在中 間。鈔名下是由花卉組成之花紋欄。中央的長方形稱為版心，分上下兩部。上部為橫書鈔票 金額「貳伯文」，其下為串錢圖案，豎行排列，方便不識字的百姓憑圖案分辨幣值。串錢圖紋 左右各有一個空格，內刻九疊篆體八思巴文，左邊那句的意思是「至元寶鈔」，右的為「諸路 通行」，其下各有「字料」、「字號」楷字。版心下半部自右至左鑄豎行楷書十行七十九字，當 眼處有「偽造者處死」、「首告者賞銀五定（錠），仍給犯人家產」的字樣，反映當局透過嚴 懲造假和利誘人們告發來抑制盜印鈔票。小鈔版亦為長方形，上額橫書「貳伯文」三字，額 下為由花葉組成之花紋欄，內為串錢圖案，交叉排列。 這兩件鈔版還要配合印章使用。元朝官府於桑皮紙正、背面墨印大、小鈔版圖紋後，為防偽 冒，會再於寶鈔正、背面各處加鈐印章多方，既有全形印，亦有騎縫印。以科技而言，古代的 防偽技術當然與現代沒法比，但作為主宰國家經濟的印刷品，歷代的鈔票無疑都代表着當 代印刷技術的尖端，體現了人類與時俱進的智慧。 Heidi Wong 09 # 5 2 8 | 0 4 . 1 2 . 2 0 1 8