一個正常人的紅血球,表面約有二百萬條決定ABO血型的H antigen左右;419Please respect copyright.PENANAVlq1Q1p2G9
除了紅血球外,H antigen均可在血管內側及大多數器官內膜上找到,可以算之為非常普遍。419Please respect copyright.PENANAIIAzd3j0SY
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雖然現今科技非常發達,全世界的科研人數亦有一定的數量,但是暫時還沒有人找得出這些H antigen的真正作用究竟是甚麼。419Please respect copyright.PENANAZGDTeHhD3E
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至少,莫論你的血型是A還是B、是AB還是O,大家亦能健健康康的成長。419Please respect copyright.PENANAM4kqGbl31b
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只不過,有研究清楚的顯示,O型血液人們裡頭的某兩種蛋白質( factor VII 和 von Willebrand factor)的含量比其他血型人士少約百分之二十五左右。419Please respect copyright.PENANASlFLb3cnAC
這兩種蛋白質輔助血液凝固,缺少這兩種蛋白質的話將會導致血流不止的出現。419Please respect copyright.PENANA6zpGSbpbCf
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反向作思考,血液裡頭這兩種蛋白質含量過高的話,亦將會增加血液凝固的機會,促成心臟梗塞的出現。419Please respect copyright.PENANAdtwlU44n26
然而,有數據指出,O型人士患心肌梗塞的機率的確是比其型血液的比較為低,可是詳細及箇中的機制尚未能搞得清楚。419Please respect copyright.PENANAIA0aUcLW3a
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「Osh! 我可是O血型的! 更甚的是,我吃薯條的時候也不會點上任何醬汁的呢!」419Please respect copyright.PENANAlIPPo39iVe
聽到心肌梗塞的數據後,一名坐在後方吃著早晨全餐的男學生把薯餅高高舉起,一臉得戚的大聲宣揚起來。419Please respect copyright.PENANA16Z91y8sMU
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「咳咳..薯餅同學,吃過多油膩食物的話,O型血液應該也幫不到你多少的呢!」419Please respect copyright.PENANAavNBAQygpj
血時裝咳了幾聲,意味深長的作出回應。419Please respect copyright.PENANAFMKb3fb8U6
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哈哈哈哈....哈哈哈哈哈!419Please respect copyright.PENANARoWBmMNZCh
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此話一出,全班同學隨即大聲歡笑起來,那名薯餅同學只好面面相覷的低著頭,細口細口咀嚼薯餅,不敢再發任何一言。419Please respect copyright.PENANAX6AQOPd8Pr
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大笑過後,血時繼續作出生動的講解起來。419Please respect copyright.PENANA9pghTF7Wre
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「我們身體裡頭的免疫系統可是勞苦功高的,二十四小時不斷運作,未曾有一刻會作出休息。419Please respect copyright.PENANAoR8fpvBiIC
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若果我們的免疫系統這一刻像第五排由我右手邊數起的第三名穿著藍色背心的男同學一樣在昏昏欲睡的話,那就真的是非常大件事了,將會有一系列的感染發生呢!」419Please respect copyright.PENANAPaL9PO8hrz
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我們的免疫細胞會在血管裡頭二十四小時不斷巡邏,它們會利用細胞表面上的antigen(抗原)來判斷出對方是否外來入侵者,並對入侵者作出一系列的應對。419Please respect copyright.PENANAu5JT2pY8TY
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以O血型人士為例,自身紅血球上的薯條(H antigen)並沒有點上任何醬汁,故此便會把點上了茄汁或甜酸醬薯條(A、B或AB血型的H antigen)的紅血球視為外來物質,製作抗體作出對抗,並把外來的紅血球除掉。419Please respect copyright.PENANAI1Alm7Dy7W
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「血時教授,有時候我見到有人會在血型上寫上O+。那個加號是不是有著甚麼意思的呢?」419Please respect copyright.PENANAJYrn2LJCZT
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「唔,那個+號其實是另一種血型分類法的表達方式來的。」419Please respect copyright.PENANAtJneSeCHRw
除了ABO血型分類方法之外,另一種較為常見的就是Rh分類方式,簡易起見通常會以正負號作表示。419Please respect copyright.PENANANs5Di9GAuV
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Rh分類法的產生源自於1939年一件悲慘的事件,在ABO分類法建立了四十年後左右。419Please respect copyright.PENANAnzU6JmAIGG
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一名懷孕中的母親急需血液輸送,她的丈夫經過ABO血液檢驗被確定為適合的捐血者,因而理所當然地把自己的血液捐給自己的老婆。419Please respect copyright.PENANAC6di3HAuLO
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無奈的是,排斥作用在捐血的過程後發生,母親的血液內含抗體把丈夫的紅血球一一消滅,產生了強大的副作用。419Please respect copyright.PENANAEJa0kBdYhS
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最終,雖然保住了母親的性命,但胎兒卻不幸地喪生。419Please respect copyright.PENANAo4aREOVY95
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經過一輪驗證,事件相信是在母親懷孕的期間裡頭開始發生的。419Please respect copyright.PENANAXj1GV5ejx2
她血液裡頭的免疫系統在懷孕時候遇上了胎兒紅血球的抗原(antigen),認定為外來之物並因而產生抗體。419Please respect copyright.PENANAu5O2VmAYPT
抗體通過胎盤進入胎兒裡頭,把其紅血球消滅,導致胎兒慘死的意外。419Please respect copyright.PENANAZih2Ecv6Fg
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然而,老公的血液裡頭有著如胎兒紅血球上一模一樣的抗原。因此在捐血的過程後,母親的免疫系統亦產生了劇烈的反應。419Please respect copyright.PENANArBJ1bFnqGf
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在事件發生後的前段時期,科學家誤以為那紅血球上的抗源與恒河猴(Rhesus Monkey)所產生出的抗體吻合,故此便把那抗原命名為 Rhesus factor。419Please respect copyright.PENANAzLVExQFQif
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後來,經過多番驗證後,最終發現原來他們擺了烏龍,導致意外發生的抗原是為另一道抗源,並不是早前發現的Rhesus factor。419Please respect copyright.PENANAVVsZgjjJ9a
但因為Rhesus 這個名字當時已廣泛使用的關係,所以便決定簡稱以Rh作最終命名,免卻Rhesus這名字所帶來的混淆及誤會。419Please respect copyright.PENANAhXw81INELH
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Rh系統比ABO系統更為複雜,相比ABO只有3種抗原組合,Rh系統的抗原組合多達49種組別之多;419Please respect copyright.PENANAjenEQwx6qd
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ABO系統的抗原主要是由碳水化合物而組成,而Rh系統的則是由蛋白質組成。419Please respect copyright.PENANAQBZMQV8nJS
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對於新生嬰兒及懷孕女士來說,Rh裡頭的D antigen相對上較為重要。正因如此,Rh系統裡頭的正和負就是代表著D antigen的存在與否。419Please respect copyright.PENANAp9KASMMlPh
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假設母親的紅血球並沒有D antigen,而父親的紅血球有著D antigen的話,其胎兒的紅血球便有機會在父親的遺傳下帶有D antigen。419Please respect copyright.PENANABi5k8vYUTw
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母親自身沒有D antigen的關係,便會把嬰兒紅血球的D antigen視作為外來之物;419Please respect copyright.PENANA0tCmpSjnlr
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她的免疫系統因而針對D antigen產生抗體,通過胎盤進入的嬰兒的血液循環系統裡頭,消除其體內的紅血球。419Please respect copyright.PENANAzdrxNtcuDC
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嘩....呀.....419Please respect copyright.PENANADtU5tCMV1K
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在場的女同學聽到這裡後,無不感到嘩然及驚恐起來,連忙拿起捐血咭查看自己究竟是正還是負。419Please respect copyright.PENANAZ08MeeTRHW
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「血時教授,在這裡我有一件事不太明白,為何在懷孕方面裡頭,我們好像只是會顧及Rh系統,而不太理會ABO血液系統的呢?」419Please respect copyright.PENANAgJ54uuC68J
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「Good Question!419Please respect copyright.PENANAt4CkRnjhIG
這位同學的Mid-term測驗我會私自加你1分!」419Please respect copyright.PENANABY7VwfMVDJ
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「吓? 1分咁小?」419Please respect copyright.PENANAHqy4yjWldg