※ [本文轉錄自 NTUmed91work 看板] 作者: montein (嘿，終於考完了) 看板: NTUmed91work 標題: [勘誤] 流病III 3/14第三節 時間: Mon Apr 4 21:01:18 2005 其實嚴格說起來應該算補充 Dear Students: The Answers: A. 第一個不懂處:老師講義上有提到Post hoc ergo propter hoc這句話, 能否請問老師一下這句話究竟是什麼意思呢? CCKing Answers: 1. Wordings: Those are from Latin words Post Hoc : After the Event Ergo: Therefore Propter Hoc: Because of this 2. True meaning and Definition: Coincidental Correlation (post hoc ergo propter hoc ) ----------------------------------------------------------------------------- Definition: The name in Latin means "after this therefore because of this". This describes the fallacy. An author commits the fallacy when it is assumed that because one thing follows another that the one thing was caused by the other. 3. Examples: (i) Immigration to Alberta from Ontario increased. Soon after, the welfare rolls increased. Therefore, the increased immigration caused the increased welfare rolls. (ii) I took EZ-No-Cold, and two days later, my cold disappeared. 4. Proof: Show that the correlation is coincidental by showing that: (i) the effect would have occurred even if the cause did not occur, or (ii) that the effect was caused by something other than the suggested cause. 5. References (Cedarblom and Paulsen: 237, Copi and Cohen: 101) B. 第二個有問題處:老師上課時有說到當初SARS事件爆發時為了找etiology, 於是開始把感染者的各組織去作細胞培養分析， 結果在病人的肺泡細胞周圍發現有許多muti-nuclear giant cell. 老師上課時說這是一個個細胞融合在一起變成的, 然而相關的機轉與這現象代表著什麼意義? CCKing Answers: 1. They found that Multi-Nuclear Giant Cells( MNGC) have the staining of SARS-coronavirus. In other words.this virus caused the cell pathology that the cytoplasm of each cells were destroyed so that you can find the NGC under the microscope to prove the CAUSAL relationship between the agent and the pathology. 2. The 2nd example is AIDS that HIV also caused MNGC which can be found in demantia patients that also explains why some AIDS patients showed up CNS problems later on. This is from the findings of UC San Francisco. In other words, MNGC demonstrated a type of pathology in the process of viral pathogenesis.Is it clear to you now? The interesting part is that numerous HIV virus particles accumulated in those MNGC under electronic microscope that might be the part of the reasons to lead pathology. C. 第三個不清楚處:也是老師上課時講SARS時提到的,SARS發病後第四天、第十一天、 第十三天採集到的血液檢體，所做的一些檢測其反應逐漸由陰性到 陽性，這是證明引起ＳＡＲＳ的是冠狀病毒的最好證據.在這裡關於 老師提的檢測我有些地方不是很懂,能否請老師為我們解說一下這些 檢測陰陽性與冠狀病毒之間的關係呢? CCKing Answers 1. If you like to show one microbe is an etilogical agent, two major scientific proof thinking pathway and methods you can do: (a) To directly detect microbial Nucleic acid or antigen (b) To detect the immune response of this etiological agent such as the antibody because of the "specificity" of immune responses - only respond to A for producing Anti-A antibody 2. If the serum of SARS patients showed "negative" antibody around day 2 of the onset of fever but turned to positive on day 20, this patient must acquried SARS-Coronavirus. The key point is that you need to collect the serum samples at DIFFERNT TIME POINTS to show the CAUSAL relationship. 3. The problem, also the best teaching example, that Chinese Hong Kong University made the mistake to think metapneumovirus was the etiological agent is that they only one time point without temporal relationship (ie. coincidentally happened rather than true cause). Is that clear to you. 4. To prove what is the true cause for the diease in infectious disease epidemic is very important because the prevention and control strategy might be differnet and you can save many numbers of more precious life if your Cause is the True Cause. I will put more slides on Tuesday beause I was too busy in one paper revision for one young professor this weekend but I have NOT forgot the slides that I will revise and put them on the web for you. THanks for your learning and reaching our educational goal to have more scientific discovery in the future. --

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