干细胞研究及其伦理学问题

干细胞是动物体内一种独特的基本细胞类型。干细胞分化时,有些成为特殊类型的细胞,另一些仍维持干细胞,准备替代机体衰老和损伤的细胞。这些干细胞本身能够复制,以供机体终生组织更新的需要。最基本的多能干细胞存在于早期胚胎中,科学家们成功分离和培育干细胞的报告,为退行性疾病主损伤甚至致合性疾病的治疗带来了新的希望,然而,与此同时也引起了世界范围的关于使用人类胚胎和死亡胎儿进行研究的伦理大争论。     

A Heideggerian Defense of Therapeutic Cloning

Debates about the legitimacy of embryonic stem-cell research have largely focused on the type of ethical value that should be accorded to the human embryo in␣vitro. In this paper, I try to show that, to broaden the scope of these debates, one needs to articulate an ontology that does not limit itself to biological accounts, but that instead focuses on the embryo’s place in a totality of relevance surrounding and guiding a human practice. Instead of attempting to substantiate the ethical value of the embryo exclusively by pointing out that it has potentiality for personhood, one should examine the types of practices in which the embryo occurs and focus on the ends inherent to these practices. With this emphasis on context, it becomes apparent that the embryo’s ethical significance can only be understood by elucidating the attitudes that are established towards it in the course of specific activities. The distinction between fertilized embryos and cloned embryos proves to be important in this contextual analysis, since, from the point of view of practice, the two types of embryos appear to belong to different human practices: (assisted) procreation and medical research, respectively. In my arguments, I highlight the concepts of practice, technology, and nature, as they have been analyzed in the phenomenological tradition, particularly by Martin Heidegger. I come to the conclusion that therapeutic cloning should be allowed, provided that it turns out to be a project that benefits medical science in its aim to battle diseases. Important precautions have to be taken, however, in order to safeguard the practice of procreation from becoming perverted by the aims and attitudes of medical science when the two practices intersect. The threat in question needs to be taken seriously, since it concerns the structure and goal of practices which are central to our very self understanding as human beings.     

The Potentiality of the Embryo and the Somatic Cell

Recent arguments on the ethics of stem cell research have taken a novel approach to the question of the moral status of the embryo. One influential argument focuses on a property that the embryo is said to possess—namely, the property of being an entity with a rational nature or, less controversially, an entity that has the potential to acquire a rational nature—and claims that this property is also possessed by a somatic cell. Since nobody seriously thinks that we have a duty to preserve the countless such cells we wash off our body every day in the shower, the argument is intended as a reductio ad absurdum of the claim that the embryo should be afforded the same moral status as a fully developed human being. This article argues that this argument is not successful and that it consequently plays into the hands of those who oppose embryonic stem cell research. It is therefore better to abandon this argument and focus instead on the different argument that potentiality, as such, is not a sufficient ground for the creation of moral obligations towards the embryo.     

Embryo genetic disorder analysis demonstration project: A model protocol

A demonstration project designed for couples at a minimum 25% risk for having a child with cystic fibrosis is being undertaken using embryo genetic disorder analysis within an organization proficient inin vitro fertilization techniques. Prior to offering the project to patients, issues were identified that needed to be addressed in order to improve the likelihood of success. We then developed a set of protocols that would enable us to introduce this new technology to our staff and to prospective patients in a consistent manner.     

辅助生殖技术与女性生殖系统肿瘤的关系及其辩证思考

辅助生殖技术给不孕患者带来了希望,为肿瘤患者保留了生育能力,另一方面也可能导致女性生殖系统肿瘤和一系列伦理学问题。因此,用哲学的观点客观地看待辅助生殖技术与女性生殖系统肿瘤发生风险之间的关系,将有助于临床医生进一步提高辅助生殖技术安全性的认识,选择最佳的促排卵方案。     

“Other selves”: moral and legal proposals regarding the personhood of cryopreserved human embryos

This essay has two purposes. The first is to argue that our moral duties towards human embryos should be assessed in light of the Golden Rule by asking the normative question, “how would I want to be treated if I were an embryo?” Some reject the proposition “I was an embryo” on the basis that embryos should not be recognized as persons. This essay replies to five common arguments denying the personhood of human embryos: (1) that early human embryos lack ontological individuation; (2) that they are members of the species Homo sapiens but not yet human persons; (3) that the argument for personhood commits the “heap argument” fallacy; (4) that since human procreation in nature is inefficient, human embryos cannot be persons; and (5) the “burning building” scenario proves that all arguments for personhood are irrational or inconsistent. The second purpose is to set forth and criticize in light of the normative judgement defended in part one the present legal situation of cryo-preserved embryos in the U.S. The essay ends by proposing legislative reforms to protect ex utero human embryos.     

从肿瘤和胚胎的相似性看恶性肿瘤研究的新思路

恶性肿瘤的研究已经取得了巨大进步,但根治癌症依然任重道远。越来越多的研究发现肿瘤细胞和胚胎细胞生物学行为存在某些相似之处,这启发人们从发育生物学角度去认识肿瘤的发生、发展,寻找逆转恶性肿瘤的方法。     

胚胎期糖皮质激素系统在光照改善小鸡记忆中的作用

该研究采用胚胎期药物注射法和小鸡一次性被动回避反应行为模型,观察了皮质酮和地塞米松对暗孵化小鸡记忆的影响,以及两类皮质激素受体颉颃剂RU-486和Spironolactone对光照以及皮质酮效应的阻断作用。结果表明,糖皮质激素可明显改善暗孵化小鸡的记忆;两类受体颉颃剂均阻断了光照和皮质酮对暗孵化小鸡记忆的改善作用,但糖皮质激素受体对小鸡记忆的作用是特异性的,盐皮质激素主要通过对小鸡的基本状态的改变来影响记忆活动。因此,糖皮质激素及其受体系统参与了光照对小鸡记忆的作用过程。     

Ethical reflections on the status of the preimplantation embryo leading to the German embryo protection act

Ethical conflicts have always been connected with new techniques of reproductive medicine such as in-vitro fertilization. The fundamental question is: When does human life begin and from which stage of development should the embryo be protected? This question cannot be solved by scientific findings only. In prenatal ontogenesis there is no moment during the development from the fertilized oocyte to a human being which could be recognized as an orientation point for all ethical problems connected with the question of the right to dispose of prenatal life (interruption of pregnancy, research on embryos). The protection of an individual human life must be valid for all in the same manner and from the very beginning on. It must not depend on value judgments or on stages of development, so-called grades of humanity, because these would then become selection criteria. Procreated life must have the right to be born. These were the essential ethical arguments which led to the German Embryo Protection Law.