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BODHI FIELD

重建世界一
基因工程引起的倫理問題《續》
REDESIGNING THE WORLD:
ETIDCAL QUESTIONS ABOUT GENETIC ENGINEERING (continued)

易象乾博士文BYRON EPSTEIN, PHD
孔果憲 中譯 CHINESE TRANSLATION BY TERESAKUNG

數年前,一家生物科技企業向歐洲專利局提出申請,所謂的「藥女」的專利,想要以基因工程改造女人,使其乳汁分泌特定的藥物。(註44a)以基因工程在實驗室中培養人類乳房的工作,也在持續進行中。不難想像的是,它們不但將作為癌症手術後的代用乳房,也將因女性對「完美」乳房的追求而帶動強大的商機。〈註45〉最近,一位基因學家倡議以基因工程培育無頭 人,以作器官移植之用。若干著名的基因學家己表示支持他的提議。(註46)

「基因工程食物」
許多科學家聲稱,食用基因工程改造的食物沒有害處,因為基因工程所改造的物質被胃酸消滅了。近來有研究(註47)顯示,基因工程改造的物質並不完全被胃酸消滅,其中有不少進入血液和腦細胞中。尤有甚者,事實證明人體細胞的天然抵抗機制,不足以將基因工程改造的物質,有效地排除於細胞外。(註48)

關於食用基因工程改造的食物所存在的危險,已有記錄可考。對人類健康的危害中,包括可能增加食物中的毒素量,以及對抗生素具抵抗力的致病生物的數量。(註49)故意地增加食物內含毒量以強化其抗蟲 力,不啻扭轉了數千年來,食用植物的選擇性繁殖過程。例如,當植物經基因工程改造來抵禦掠食者,植物的防禦系統通常含有合成的天然致癌物。(註50)

生產基因工程改造的食物時,工業上的失誤或疏忽可能引發嚴重的問題。做為補充食品的L-色氨酸 ( L- Tryptophan),屬於氨基酸的一種,被推銷為天然 的鎮定劑與安眠藥,是以基因工程製造的。它導致至少三十人死亡、一千五百人罹患無法醫治的「嗜酸性 細胞增生〈濔漫性〉肌痛症候群」(eosinophilia myalgia syndrome)(簡稱EMS)精神系統疾病,而終生殘廢。〈註51〉  

附註:
45.見傑瑞米﹒儒傅金(JeremyRifkin)著〈生 物科技之世紀〉第二十四至二十五頁。

46. 『拜思大學(Bath Universityl『成長生物學』 教授、兼胚胎學先驅的強納森﹒斯萊克(Jonathan Slack)宣佈,他可以藉由操縱特定的基因,輕易地創 造出無頭青蛙的胚胎......他宣稱此項突破可用於人類的胚胎,因為同樣的基因,在青蛙與人類的身體裡,從事相似的作用。斯萊克說,用完整複製的人類胚胎來培養器官,是不可能的,除非先將人殺死,而這樣形同謀殺......斯萊克的觀念激怒了部份的學者。牛津大學的動物道德家安德魯﹒林西(如Idrew Linzey)教授,駁斥他的研究。林西說:「這種思想令人難以置信。這是科學法西斯主義,因為我們將創造出其他的生命,而它們生存的唯一目的,是為主宰者服務。創造變形的生命是道德退化。」不過其他的科學家支持斯萊克,提高這樣具爭議性研究的知名度......倫敦大學學院的應用醫藥生物學教授陸易斯﹒吳波(LewisWo恥的,聲稱斯萊克的建議完全合理,並且原則上 是可行的。「這裡沒有道德的問題,因為我們沒傷害任何人。問題是公眾能否接受,關鑑在於會不會令公 眾覺得『噁心』。」』 〈刊載於一九九七年十月十九日〈倫敦週日時報〉的「無頭青蛙替人類器官工廠開道」 一文。)

47.教科書上說,在食物中的脫氧核酸(DNA) 應該會被消化掉而摧毀,但是杜夫勒(Dorfler)與他的學生瑞納﹒舒柏特(Rainer Schubbert)發現,當他們名為M13的細菌型濾過性病原體餵與老鼠時,約有七百個「字母」長的脫氧核酸(DNA)﹝含一個基因﹞, 存活下來而出現在糞便裡。研究人員懷疑,是否有一些基因的片斷已經透入老鼠的細胞。他們提取老鼠的細胞,以染色分子探測,如果染色分子與M13結合,就會發出光。探測的分子不單在腸內,更在脾臟 、白血球和肝臟內發光。杜夫勒表示:「它們並不難找。在某些案例中,甚至每一千個細胞中就有一個濾過性的脫氧核酸(DNA)。」 通常脫氧核酸(DNA)在細胞中待的時間不久,過了十八小時之後,多數的 細胞都有方法將濾過性的侵入者排除。但是杜夫勒推測,偶爾一些外來的脫氧核酸(DNA)仍會留存下來。  

48.基因學家約瑟夫﹒康明斯(JosephOmunins) 評論道:  
脫氧核酸(DNA)經由食物而併入人體染色體一事,仍然是鮮活的議題。事實證明的確有合併的情形   .....。細胞吸收後,在某些案例中,可能引發poptosis (細胞自殺),但是杜夫勒證明成熟健康的細胞的確會將外來的脫氧核酸(DNA)併入染色體內。目前對這種合併的情形下斷言還過早,由於食物是各種的免疫與自動免疫疾病,乃至精神病的幫兇(嚴重慢性消化不良(Celiacs)出現的精神疾病的機率非常高),對於併入脫氧核酸(DNA)的疾病所扮演的角色,應該調查,避免盲目地妄下結論。在進化的歷史上,都有特定食物的脫氧核酸(DNA)被併入體腔細胞的染色體內。基因工程的危險,在於極度擴大地併入濾過性促進物質( promoter),細菌性基因和人造基因(普遍為Monsanto公司所使用),將引發新的危機......(一九九八年八月十八日私人電子郵件通訊。)  

亦參考R﹒舒伯特( R Schubbert)、C﹒賴特曼(C Lettman)與W﹒杜夫勒(W. Dorfier)合著、刊載於一九九四年第二四二期的(分子基因學〉第四九五至五O四頁的「攝取的外來(phage M13)脫氧核酸(DNA)在腸胃道中短暫存活、並進入老鼠的血液」一文。  

48. 『常久以來的假設是我們的胃腸充滿酵素, 能快速地消化脫氧核酸(DNA)。在一項試驗濾過性脫氧核酸(DNA)在胃腸中存活的研究裡,老鼠被餵以細菌的濾過性病原體的脫氧核酸(DNA),其中一大部份在通過胃腸之後存活下來,並且進入血液。研究小組證明攝取的脫氧核酸(DNA)最終不單到達了老鼠的胃腸細胞裏,更到了脾臟和肝臟的細胞,以及白血球細胞。「在某些案例中,甚至每一千個細胞中就有一個濾過性的脫氧核酸(DNA)。」』引用何(Ho,譯音)之著作,第一四一頁。  

49.對抗生素真抵抗力的生物的蔓延,是基因工 程一項危險的副產品。對抗生素具抵抗力的基因,在接和基因的過程中,經常被用來做為標記基因,它們繼而能經由橫向轉移而蔓延。如前所述,抗生素被大穿量的噴灑在農作物上,以反制所謂終結者科技的效應。  

50.一九八九年六月十六日(科學〉第一二三三 頁。  

51.約翰﹒費根(John Fagan)博士著「色胺酸之結論」一文,公佈在http://home1.swipnet.se/-w-18472/ jftrypt.htm。顯然,基因工程改造的色胺酸, 又在市場上出現了,並仍然具有與當初引發問題時,相同的危險特性:  

根據美國研究人員所言,重新處方的食物補充品,可能含有與先前被禁的產品相同的有害汙染物。L-色胺酸是一種天然存在的氨基酸,一九九O年,當日本爆發了罕見的、名為「嗜酸性細胞增生肌痛症候群J (eosinophilia myalgia syndrome,簡稱EMS)的血液疾病時,發現了二者之間的關連。那次疾病的爆發影響了一千五百人,並導致三十人死亡。對於這被促銷為幫助睡眠和飲食的產品,研究顯示它含有一種無法鑑定的汙染物質,俗稱「X頂峰」。科學家無法確定是這汗染物質,或是L色胺酸,或是二者的組合而導致疾病。數家廠商後來將產品重新配方,新的品牌包含5-氫氧化-L-色氨酸。這種產品在美國毋需醫師處方就可以買到。明尼蘇達州「美優診所」的研究人員史進芬﹒內勒( Stephen Naylor)與傑洛德﹒葛萊契(Gerald Gleich),檢查了六種品牌,以確定其中含原汙染物的成份。他們在八月三十一日星期一,公佈說所有的六個品牌都顯示了「X頂峰」的特徵。其中所含的程度,是檢驗的原產品中程度的3%到   15%不等。葛萊契說,他們尚未聽聞新產品與任何   EMS的爆發有關,但是他表示「有這個可能性。」 內勒和葛萊契的發現,公佈在九月刊的「自然醫藥」雜誌上,而食品藥物管理局也宣佈,它已經證實了這項結果。(「重新配方的食物補充品與被禁的原處方一樣壞」﹝由沙恩﹒摩理斯( Shane Morris)公佈在 GENfEQ-I@ping.de listserv上﹞〉。

數篇有關此主題的文章,包括上述的研究報告 ,都刊載在一九九八年八月二十九日第三五二冊、第九一二九期的〈刺絡針〉上。

待續


A few years ago a biotech corporation applied to the European Patent Office for a patent on a so-called 'pharm-woman,' the idea being to genetically engineer human females so that their breast-milk would contain specialized pharrnaceuticals.44a Work is also ongoing to use genetic engineering to grow human breasts in the laboratory. It doesn't take much imagination to realize that not only would they be used for breast replacement needed due to cancer surgery, but also to foster a vigorous commercial demand by women in search of the "perfect" breasts.45 A geneticist has recently proposed genetically engineering headless humans to be used for body parts. Some prominent geneticists have supported his idea.46  

Genetically Engineered Food  

Many scientists have claimed that the ingestion of genetically engineered food is harmless because the genetically engineered materials are destroyed by stomach  acids. Recent research47 suggests that genetically engineered materials are not completely destroyed by stomach acids and that significant portions reach the bloodstream and also the brain-cells. Furthermore, it has been shown that the natural defense mechanisms of body cells are not entirely effective in keeping the genetically engineered substances out of the cells.48

Some dangers of eating genetically engineered foods are already documented. Risks to human health include the probable increase in the level of toxins in foods and in the number of disease-causing organisms that are resistant to antibiotics.49 The purposeful increase in toxins in foods to make them insect-resistant is the reversal of thousands of years of selective breeding of food-plants.  

For example when plants are genetically engineered to resist predators, often the plant defense systems involve the synthesis of natural carcinogens.50

Industrial mistakes or carelessness in production of genetically engineered food ingredients can also cause serious problems. The l-tryptophan food supplement, an amino acid that was marketed as a natural tranquilizer and sleeping pill, was genetically engineered. It killed at least thirty people and permanently disabled 1,500 others with an incurable nervous system condition known as eosinophilia myalgia syndrome (EMS).51

NOTES:
45. See Jeremy Rifkin, Biotech Century, pp. 24-25.  

46. "Jonathan Slack, professor of developmental biology at Bath University and a leading embryologist, says he can now create headless frog embryos relatively easily by manipulating certain genes... He said the breakthrough could be applied to human embryos because the same genes perform similar functions in both frogs and humans. Using intact cloned human embryos to grow organs would be out of the question because they would have to be killed and this would be equivalent to murder, Slack said... Slack's ideas have angered some academics. Professor Andrew Linzey, an animal ethicist at Oxford University, denounced his research." This sort of thinking beggars belief. It's scientific fascism because we would be creating other beings whose very existence would be to serve the dominant group. It is morally regressive to create a mutant form of life," Linzey said. Other scientists, however, support Slack in raising the profile of such controversial research .... Lewis Wolpert, professor of biology as applied to medicine at University College London, said Slack's suggestions were perfectly sensible and could in principle be possible. "There are no ethical issues because you are not doing any harm to anyone. "It is a question of whether it is acceptable or not to the public and that depends on the 'yuk' factor." ("Headless frog opens way for human organ factory," London Sunday Tinrs, October 19,1997.)

47. Textbooks say that DNA in food should be digested and destroyed. But Dorfler and his student Rainer Schubbert found that when they fed a bacterial virus called [1]M13 to a mouse, sections of its genetic material about 700 DNA "letters" long-large enough to contain a gene- survived to emerge in faeces. The researchers wondered whether a few of these genetic snippets had managed to penetrate the mouse's cells. They took cells from the mice and probed them with a dye molecule that lights up when it binds to the M13 DNA. The probe lit up inside cells not only from the intestine, but the spleen, white blood cells and liver. "They weren't hard to find," says Dorfler. "In some cases as much as one cell in a thousand had viral DNA." Usually the DNA does not stay long inside the cells. After 18 hours, most cells had somehow ejected the viral intruders. But Dorfler speculates that occasionally some foreign DNA may remain. (New Scientist, Jan. 4,1997).

Geneticist Joseph Cummins has commented:

The matter of DNA being incorporated into human chromosome from food is still alive and active. The fact is clear that such incorporation takes place... Uptake into cells may trigger apoptosis (cell suicide) in some cases but Doerfler showed that mature healthy cells do incorporate foreign DNA into chromosomes. It is too early to make conclusions about the consequences of such incorporation. Since food is implicated in a variety of immune and autoimmune diseases as well as mental illness (Celiacs have very high incidence of mental illness) the role of incorporated DNA disease should be investigated and blind conclusions should be avoided. Certainly food DNA has been incorporated into somatic cell chromosomes throughout evolutionary history. The danger of genetic engineering is related to the greatly amplified incorporation of viral promoters, bacterial genes and synthetic genes (widely employed by Monsanto) causing new risks... (personal email communication, August 18, 1998). See also Schubbert, R, Lettman, C and Doerfler, W. "Ingested foreign (phage M13) DNA survives transiently in the gastrointestinal tract and enters the bloodstream of mice," Mol. Genet. 242 (1994): 495-504.

48. 'It has long been assumed that our gut is full of enzymes which can rapidly digest DNA. In a study designed to test the survival of viral DNA in the gut, mice were fed DNA from a bacterial virus, and large fragments were found to survive passage through the gut and to enter the blood stream. This research group has now shown that ingested DNA end up, not only in the gut cells of the mice, but also in spleen and liver cells as well as white blood cells. "In some cases, as much as one cell in a thousand had viral DNA."' Ho, op. cit.., p. 141.  

49. The spread of antibiotic resistant organisms is a dangerous by-product of genetic engineering. Antibiotic resistant genes are often used as marker genes in the process of gene-splicing. They can then be spread by horizontal transfer. As mentioned above, antibiotics are also sprayed on crops in large quantities to unlock the effect of the so-called Terminator technology.  

50. Science, 16 June 1989, p. 1233.       51. John B. Fagan, Ph.D., "Tryptophan surnmary," http://home1.swipnet.se/~w-18472/jftrypt.htm. Apparently genetically engineered tryptophan is already back on the market with the same dangerous characteristics that caused the initial problems:

A reformulated food supplement could contain harmful contaminants similar to those found in an earlier banned version of the product, according to US researchers. L-trytophan, a naturally occurring amino acid, was banned in 1990 after the product was linked to a Japanese outbreak of a rare blood disease called eosinophilia myalgia syndrome (EMS). The outbreak affected 1,500 people and killed 30. Studies of the product, which was promoted as a sleep and diet aid, revealed it contained an unidentified contaminant nicknamed 'peak X'. Scientists could not determine whether the contaminant, or L-trytophan, or a combination of the two caused the disease. Several manufacturers have since reformulated the product into brands containing 5-hydroxy-L-trytophan. The product is widely available over-the-counter in the US. Stephen Naylor and Gerald Gleich at the Mayo Clinic in Minnesota examined six brands for traces of the original contaminant. All six showed the 'peak X' signature, they said on Monday 31 August. The levels varied between 3-15% of those observed in a test on the original product. Gleich said they were not aware of the new formulations being associated with any outbreaks of EMS, but said the 'potential was there.' The Food and Drug Administration said it had confirmed Naylor and Gleich's findings, which are published in the September issue of the journal Nature Medicine. ("Remade Food Supplement as Bad as Banned Original" [posted by Shane Morris on the GENTECH@ping.de listserv Sept. 2,1998]).  

Several articles on the subject, including those reporting the research mentioned above, were published in The Lancet 352, no. 9129 (Aug. 29,1998).  

 ~ To be continued  

 

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