Hiển thị các bài đăng có nhãn cloning. Hiển thị tất cả bài đăng
Hiển thị các bài đăng có nhãn cloning. Hiển thị tất cả bài đăng

Thứ Hai, 6 tháng 4, 2015

The Cloning Sourcebook

The Cloning Sourcebook



Animal cloning has developed quickly since the birth of Dolly the sheep. Yet many of the first questions to be raised still need to be answered. What do Dolly and her fellow mouse, cow, pig, goat and monkey clones mean for science? And for society? Why do so many people respond so fearfully to cloning? What are the ethical issues raised by cloning animals, and in the future, humans? How are the makers of public policy coping with the stunning fact that an entire animal can be reconstructed from a single adult cell? And that humans might well be next? The Cloning Source Book addresses all of these questions in a way that is unique in the cloning literature, by grounding what is effectively an interdisciplinary conversation in solid science. In the first section of the book, the key scientists responsible for the early and crucial developments in cloning speak to us directly, and other scientists evaluate and comment on these developments. The second section explores the context of cloning and includes sociological, mythological, and historical perspectives on science, ethics, and policy. The authors also examine the media’s treatment of the Dolly story and its aftermath, both in the United States and in Britain. The third section, on ethics, contains a broad range of papers written by some of the major commentators in the field. The fourth section addresses legal and policy issues. It features individual and collective contributions by those who have actually shaped public policy on reproductive cloning, therapeutic cloning, and similarly contentious bioethical issues in the United States, Britain, and the European Union. Animal cloning continues for agricultural and medicinal purposes, the latter in combination with transgenics. Human cloning for therapeutic purposes has recently been made legal in Britain. The goal is to produce an early embryo and then derive stem cells that are immunologically matched to the donor. Two human reproductive cloning projects have been announced, and there are almost certainly others about which we know nothing. Sooner or later a cloned human will be born. Many lessons can be learned from the cloning experience. Most importantly, there needs to be a public conversation about the permissible uses of new and morally murky technologies. Scientists, journalists, ethicists and policy makers all have roles to play, but cutting-edge science is everybody’s business. The Cloning Sourcebook provides the tools required for us to participate in shaping our own futures.




Thứ Hai, 23 tháng 2, 2015

Development and Engineering of Dopamine Neurons

Development and Engineering of Dopamine Neurons



The neurotransmitter dopamine has just celebrated its 50th birthday. The discovery of dopamine as a neuronal entity in the late 1950s and the notion that it serves in neurotransmission has been a milestone in the field of neuroscience research. This milestone marked the beginning of an era that explored the brain as an integrated collection of neuronal systems that one could distinguish on basis of neurotransmitter identities, and importantly, in which one started to be able to pinpoint the seat of brain disease. The mesodiencephalic dopaminergic (mdDA) system, previously designated as midbrain dopaminergic system, has received much attention since its discovery. The initial identification of dopamine as a neurotransmitter in the central nervous system (CNS) and its relevance to psychiatric and neurological disorders have stimulated a plethora of neurochemical, pharmacological and genetic studies into the function of dopamine neurons and their projections. In the last decade, studies on gene expression and development have further increased the knowledge of this neuronal population and have unmasked a new level of complexity. The start of the molecular dissection of the mdDA system has been marked by the cloning and characterization of Nurr1 and Pitx3. These transcription factors were shown to have a critical function during mdDA development. These initial studies have been followed by the identification of many other proteins that have a crucial function in the creation of a dopamine neuron permissive region, induction of precursors, induction of terminal differentiation and finally maintenance of the mdDA neuronal pool. In addition, work showing that the historically distinguished regions of the substantia nigra pars compacta (SNc) and ventral tegmental area (VTA ) harbor molecularly distinct sets of neuronal groups with specific connectivity patterns has added a new layer ofcomplexity to how mdDA neurons are generated and function in the adult CNS. The current challenge in the field of dopamine research is to characterize the full extent of molecular processes that underlie mdDA neuron programming and to translate these findings into viable approaches for embryonic stem (ES)-cell engineering as an ultimate treatment of degenerative diseases as Parkinsons disease. The chapters presented in this book provide an overview of the different stages that are distinguished during mdDA neuronal development. Chapter 1 discusses the dopamine systems of the zebrafish, being a powerful model organism for genetic intervention on the developmental programming of neuronal systems. In Chapter 2 an overview is presented of dopamine systems that are present in the vertebrate CNS. Chapters 3-6 discuss the early specification of dopamine precursors and the programs that lead to terminal differentiation. In Chapters 7 and 8 the maintenance of dopamine neurons is discussed with a special emphasis on neurotrophic support. The specific connectivity of the dopamine system and the axon guidance rules that apply to developing dopamine neurons are described in Chapter 9. An overview of ES-cell engineering of dopamine neurons is presented in Chapters 10 and 11. The research directed towards unraveling the molecular programming of mdDA neurons continues to be highly exciting. One may expect that novel biological principles will continue to emerge from this population of neurons. In the near future the field as a whole will mature towards a more comprehensive understanding of mdDA neuronal development and network integration, and will continue to apply knowledge of dopamine neuron development and function to the treatment of human disease.




Thứ Ba, 13 tháng 1, 2015

Drug Addiction and Related Clinical Problems

Drug Addiction and Related Clinical Problems



The book gives an update on different aspects of drug addiction and AIDS. The first chapters deal with the biological aspects of drug addiction, from cloning of brain opioid receptors to the mechanisms of dependence development. The second part confirms the validity of methadone maintenance treatments in controlling heroin addiction, and shows the spreading of methadone use in different European countries. Methadone maintenance also appears as the most valid strategy in HIV epidemics prevention. The most recent acquisition on AIDS diagnostic criteria and treatment protocols are discussed. The debate on these topics remains unresolved but the authoritative opinions and the significant data reported will help in attenuating emotionality, and will favor a progressively more pragmatic approach.