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Biomedical subjects

R G Edwards

Publications and source records attributed to R G Edwards.

At least 37 records · Page 2Linked to original sources

Towards single births after assisted reproduction treatment.

The cause of increases in recorded multiple births is undoubtedly assisted human conception. Many arise when three or more embryos are replaced after IVF or ISCI. Others are due to multi-ovulation during artificial insemination or intrauterine inseminations, since complete control over numbers of ovulated eggs following ovarian stimulation is not fully possible. The frequency of multiple IVF births is best controlled by reducing numbers of transferred embryos to one or two. Methods to induce ovarian stimulation in amenorrhoeic and then in cyclic women 30 years ago have been greatly refined and extended in current practice. Curiously, a great many of them produce oocytes which fail to implant after fertilization, whether natural or induced cycles are being used. This massive failure of most embryos to implant poses numerous questions on the evolution of this situation in humans.

Animals↗

United Nations and human cloning: a slender and fortunate defence for biomedical research.

Numerous biomedical scientists have contributed to the wide knowledge on the growth of preimplantation human embryos in vitro, now improving every aspect of the form of clinical care. These data were gained ethically in many countries, to open new vistas including the alleviation of infertility, preimplantation genetic diagnosis and stem cells, combined with some recent reports on human reproductive cloning. After detailed consultations with scientists, clinicians, ethicists and lawyers, many governments passed legislation permitting research under their own particular socially-defined conditions. Virtually all of them rejected reproductive cloning; a few have accepted therapeutic cloning. These legislatures saluted the many biomedical scientists striving to improve IVF and its derivatives, recognizing their immense medical potential. A motion recently placed before the United Nations then recommended a worldwide ban on all forms of human cloning. Proponents included the Vatican and many Roman Catholic countries, the USA and others. Opponents included Belgium, China, Japan, Brazil, UK, Germany and France. Mediation was achieved by Iran and other Muslim nations, and led to a motion passed by single vote for a two-year delay. This may be the first-ever proposal to ban worldwide a particular form of research. It sounds the alarm bells for further research. It raises questions about the UN being an appropriate forum for ethical decisions affecting the entire world and its future medicine. Large blocs of nations committed to particular religions and outlooks confronted each other, a situation in total contrast to the detailed and widespread consultations made by individual governments when deciding their own individual ethics. This event was clearly a narrow escape for free research as defined by each country's own jurisprudence. It also places research on human embryology and reproductive biomedicine into a more critical situation than before. Current liberalism in studies on assisted conception, clearly threatened by powerful adversaries, will have to be fortified to maintain the current impetus into newer forms of clinical care.

Cloning, Organism↗

Regulatory systems in early mammalian development, with especial reference to polarity and totipotency.

Increasing evidence is now available to reveal some of the underlying regulatory systems regulating early mammalian embryogenesis. These include timing, integration, multipotency, polarities and other embryological systems. This paper deals mostly with polarities and axes, and their integration with other regulatory phenomena. Various morphogenetic aspects of ovulated oocytes and cleavage planes have long been suspected as displaying gradients, and events such as ooplasmic rotation at sperm entry, the imposition of nucleolar polarity and the highly regulated cleavage planes add to this evidence. Examples of proteins that form gradients according to the embryonic axes are increasing in number, and provide molecular evidence of their nature in establishing a persistent polarity throughout early cleavage stages. The same polarised systems are also involved in the blastocyst and implantation, and their characteristics influence implantation and the post-implantation growth of the embryo. More knowledge on each of these major regulatory systems is needed to clarify the exact nature of early mammalian differentiation and organogenesis.

Animals↗