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專題結構
1. 原文
Paradigm shift is an overused term. Properly, it refers to a radical change of perspective on a topic, such as the move from the physics of Newton to the physics of Einstein, or the introduction of plate tectonics into geology. Such things are rare. Something which history may come to regard as a true paradigm shift does, however, seem to be going on at the moment in medicine. This is a recognition that the zillions of apparently non-pathogenic bacteria on and in human bodies, hitherto largely ignored, are actually important for people’s health. They may even help to explain the development of some mysterious conditions.
One such condition is autism—these days often called autism-spectrum disorder (asd). asd is characterised by repetitive, stereotypical and often restricted behaviour such as head-nodding, and by the difficulties those with it have in reading the emotions of, and communicating with, other people. These symptoms are noticeable in children from the age of two onwards. Currently, in America, about one child in 59 is diagnosed with asd.
What causes asd has baffled psychiatrists and neurologists since the syndrome was first described, in the mid-20th century, by Hans Asperger and Leo Kanner. But the evidence is pointing towards the bacteria of the gut. That suggestion has been reinforced by two recently published studies—one on human beings and one on laboratory rodents.
The human study, the latest results of which came out a few weeks ago in Scientific Reports, is being conducted by Rosa Krajmalnik-Brown of Arizona State University and her associates. It was prompted by earlier work in which Dr Krajmalnik-Brown and James Adams, a colleague at Arizona State, sequenced the dna of gut bacteria from 20 autistic children to discover which species were present. They found that the children in their sample were missing hundreds of the thousand-plus bacterial species that colonise a 「neurotypical」 person’s intestine. One notable absence was Prevotella. This bug, which makes its living by fermenting otherwise-indigestible carbohydrate polymers in dietary fibre, is abundant in the alimentary canals of farmers and hunter-gatherers in places like Africa, rare in western Europeans and Americans, and nearly nonexistent in children with asd.
Their discovery led Dr Krajmalnik-Brown and Dr Adams to the idea that restoring the missing bacteria might alleviate autism’s symptoms. Two years ago they tested a process called microbiota transfer therapy (mtt) on 18 autistic children aged between seven and 16. Of their participants 15 were regarded, according to the Childhood Autism Rating Scale, as having 「severe」 autism.
MTT is a prolonged version of a process already used to treat infection by a bug called Clostridium difficile, which causes life-threatening diarrhoea. It involves transplanting carefully prepared doses of faecal bacteria from a healthy individual to a patient. The researchers gave the children, first, an oral antibiotic, a bowel cleanse and an oral antacid (to ensure that microbes administered by mouth would survive their passage through the stomach). They followed this up with either an oral or a rectal dose of gut bacteria, and then, for seven to eight weeks, a daily antacid-assisted oral dose. Ten weeks after treatment started the children’s Prevotella levels had multiplied 712-fold.In addition, those of another species, Bifidobacterium, had quadrupled. Bifidobacterium is what is known as a 「probiotic」 organism—something that acts as a keystone species in the alimentary ecosystem, keeping the mixture of gut bacteria healthy. Now, two years later, although levels of Prevotella have fallen back somewhat, they are still 84 times higher than they were before the experiment started. Levels of Bifidobacterium, meanwhile, have gone up still further—being five times higher than they had been at the beginning of the study. This, says Dr Krajmalnik-Brown, suggests the children’s guts have become healthy environments that can recruit beneficial microbes by themselves...
2. 原文解析
Paradigm shift is an overused term. Properly, it refers to a radical change of perspective on a topic, such as (常用於表示舉例) the move from the physics of Newton to the physics of Einstein, or (or前後引導的兩個名詞平行) the introduction of plate tectonics into geology. Such things are rare. Something which (就近修飾something且在後面的從句中充當regard的賓語) history may come to regard as a true paradigm shift does, however, seem to be going on at the moment in medicine. This is a recognition that the zillions of apparently non-pathogenic bacteria on and in human bodies, hitherto (迄今為止) largely ignored, are actually important for people’s health. They (指代前面的zillions of bacteria) may even help to explain the development of some mysterious conditions.
One such condition is autism—these days often called autism-spectrum disorder (asd). asd is characterised by repetitive, stereotypical and (同一套平行只需要在最後一個平行元素前面補出and) often restricted behaviour such as head-nodding, and by the difficulties those with it have in reading the emotions of, and communicating with, other people. These symptoms are noticeable in children from the age of two onwards. Currently, in America, about one child in 59 is diagnosed with asd.
What causes asd (what引導的名詞性從句作為主語) has baffled (困惑) psychiatrists and neurologists since the syndrome was first described, in the mid-20th century, by Hans Asperger and Leo Kanner. But the evidence is pointing towards the bacteria of the gut. That suggestion has been reinforced by two recently published studies—one on human beings and one on laboratory rodents.
The human study, the latest results of which came out a few weeks ago in Scientific Reports, is being conducted by Rosa Krajmalnik-Brown of Arizona State University and her associates. It was prompted by earlier work in which Dr Krajmalnik-Brown and James Adams, a colleague at Arizona State, sequenced the dna of gut bacteria from 20 autistic children to (此處表目的) discover which species were present (which引導的從句作名詞). They found that the children in their sample were missing hundreds of the thousand-plus bacterial species that colonise a 「neurotypical」 person’s intestine. One notable absence was Prevotella. This bug, which makes its living by fermenting (發酵) otherwise-indigestible carbohydrate polymers in dietary fibre, is abundant in the alimentary(食物的) canals of farmers and hunter-gatherers in places like (like在GMAT不能用於表示舉例) Africa, rare in western Europeans and Americans, and nearly nonexistent in children with asd.
Their discovery led Dr Krajmalnik-Brown and Dr Adams to the idea that (that引導的從句作noun modifier就近修飾idea) restoring the missing bacteria might alleviate autism’s symptoms. Two years ago (搭配一般過去時) they tested a process called microbiota transfer therapy (mtt) on 18 autistic children aged (就近修飾children) between seven and 16. Of their participants, 15 were regarded, according to the Childhood Autism Rating Scale, as having 「severe」 autism.
MTT is a prolonged version of a process already used to treat infection by a bug called Clostridium difficile, which causes life-threatening diarrhoea. It involves transplanting carefully prepared doses of faecal bacteria from a healthy individual to (平行標誌詞) a patient. The researchers gave the children, first, an oral antibiotic, a bowel cleanse and an oral antacid (to ensure that microbes administered by mouth would survive their passage through the stomach). They followed this up with either an oral or a rectal dose of gut bacteria, and then, for seven to eight weeks, a daily antacid-assisted oral dose. Ten weeks after treatment started, the children’s Prevotella levels had multiplied 712-fold. In addition, those of another species, Bifidobacterium, had quadrupled. Bifidobacterium is what is known as a 「probiotic」 organism—something that acts as a keystone species in the alimentary ecosystem, keeping (comma + ving作副詞修飾語修飾鄰近的句子, 為其提供額外的信息) the mixture of gut bacteria healthy. Now, two years later, although levels of Prevotella have fallen back somewhat, they are still 84 times higher than they were (句子和句子進行比較) before the experiment started. Levels of Bifidobacterium, meanwhile, have gone up still further—being five times higher than they had been at the beginning of the study. This(this在GMAT當中大概率不能作為名詞單獨出現), says Dr Krajmalnik-Brown, suggests the children’s guts have become healthy environments that can recruit beneficial microbes by themselves
3. 邏輯結構
P1：提出觀點：最近發現的細菌跟某些疾病有關可以理解為paradigm shift
↓
P2：論據：介紹自閉症
↓
P3-P5：論據：細菌的存在有可能導致自閉症，直接證明這個發現為什麼可以被認為是paradigm shift
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