Edward P. Evans

Bio: Edward P. Evans is an academic researcher from University of Oxford. The author has contributed to research in topics: X chromosome & Stem cell. The author has an hindex of 29, co-authored 45 publications receiving 7827 citations.

New cell lines from mouse epiblast share defining features with human embryonic stem cells

Abstract: The application of human embryonic stem (ES) cells in medicine and biology has an inherent reliance on understanding the starting cell population. Human ES cells differ from mouse ES cells and the specific embryonic origin of both cell types is unclear. Previous work suggested that mouse ES cells could only be obtained from the embryo before implantation in the uterus. Here we show that cell lines can be derived from the epiblast, a tissue of the post-implantation embryo that generates the embryo proper. These cells, which we refer to as EpiSCs (post-implantation epiblast-derived stem cells), express transcription factors known to regulate pluripotency, maintain their genomic integrity, and robustly differentiate into the major somatic cell types as well as primordial germ cells. The EpiSC lines are distinct from mouse ES cells in their epigenetic state and the signals controlling their differentiation. Furthermore, EpiSC and human ES cells share patterns of gene expression and signalling responses that normally function in the epiblast. These results show that epiblast cells can be maintained as stable cell lines and interrogated to understand how pluripotent cells generate distinct fates during early development.

Changing potency by spontaneous fusion

Abstract: Recent reports have suggested that mammalian stem cells residing in one tissue may have the capacity to produce differentiated cell types for other tissues and organs (1–9). Here we define a mechanism by which progenitor cells of the central nervous system can give rise to non-neural derivatives. Cells taken from mouse brain were co-cultured with pluripotent embryonic stem cells. Following selection for a transgenic marker carried only by the brain cells, undifferentiated stem cells are recovered in which the brain cell genome has undergone epigenetic reprogramming. However, these cells also carry a transgenic marker and chromosomes derived from the embryonic stem cells. Therefore the altered phenotype does not arise by direct conversion of brain to embryonic stem cell but rather through spontaneous generation of hybrid cells. The tetraploid hybrids exhibit full pluripotent character, including multilineage contribution to chimaeras. We propose that transdetermination consequent to cell fusion (10) could underlie many observations otherwise attributed to an intrinsic plasticity of tissue stem cells (9).

An air-drying method for meiotic preparations from mammalian testes.

Abstract: A suspension is made in isotonic (2.2%) sodium citrate solution from the contents of the tubules from a whole testis or a testicular biopsy specimen. The germinal cells are sedimented by centrifuging, leaving most of the sperm in the supernatant fluid, which is discarded. The cells are resuspended in hypo-tonic (1%) sodium citrate solution and left to stand at room temperature for 12 minutes, after which they are sedimented again and fixed as a concentrated suspension in a mixture of 3 parts absolute ethyl alcohol to 1 part glacial acetic acid plus a trace of chloroform. Two quick changes into fresh fixative follow. Air-dried preparations are made from the final fixed suspension and stained in lactic-acetic-orcein. The method is suitable for stages of male meiosis in which the chromosomes are condensed. Its principle advantage is the separation of the clumps of spermatogonia and spermatocytes into individual cells which are randomly dispersed over the preparations. Compared with squash techniques, the air-drying method gives improved spreading of the chromosomes and less cell breakage.

Establishment of germ-line-competent embryonic stem (ES) cells using differentiation inhibiting activity

Abstract: The regulatory factor Differentiation Inhibiting Activity/Leukaemia Inhibitory Factor (DIA/LIF) suppresses the differentiation of cultured embryonic stem (ES) cells. In the present study, it is shown that ES cell lines can be derived and maintained in the absence of feeder layers using medium supplemented with purified DIA/LIF. These cells can differentiate normally in vitro and in vivo and they retain the capacity for germ-line transmission. DIA/LIF therefore fulfils the essential function of feeders in the isolation of pluripotential stem cells.

Pluripotency of mesenchymal stem cells derived from adult marrow

Abstract: We report here that cells co-purifying with mesenchymal stem cells--termed here multipotent adult progenitor cells or MAPCs--differentiate, at the single cell level, not only into mesenchymal cells, but also cells with visceral mesoderm, neuroectoderm and endoderm characteristics in vitro. When injected into an early blastocyst, single MAPCs contribute to most, if not all, somatic cell types. On transplantation into a non-irradiated host, MAPCs engraft and differentiate to the haematopoietic lineage, in addition to the epithelium of liver, lung and gut. Engraftment in the haematopoietic system as well as the gastrointestinal tract is increased when MAPCs are transplanted in a minimally irradiated host. As MAPCs proliferate extensively without obvious senescence or loss of differentiation potential, they may be an ideal cell source for therapy of inherited or degenerative diseases.

A simple and general method for transferring genes into plants

Abstract: Transformed petunia, tobacco, and tomato plants have been produced by means of a novel leaf disk transformation-regeneration method. Surface-sterilized leaf disks were inoculated with an Agrobacter...

Induction of Pluripotent Stem Cells From Adult Human Fibroblasts by Defined Factors

Abstract: If it were possible to reprogram differentiated human somatic cells into a pluripotent state, patient-specific and disease-specific stem cells could be developed. Previous work generated induced pluripotent stem (iPS) cells capable of germline transmission from murine somatic cells by transd

sources and effects of ionizing radiation

Abstract: NOTE The report of the Committee without its annexes appears as Official Records of the General Assembly, Sixty-third Session, Supplement No. 46. The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The country names used in this document are, in most cases, those that were in use at the time the data were collected or the text prepared. In other cases, however, the names have been updated, where this was possible and appropriate, to reflect political changes. Scientific Annexes Annex A. Medical radiation exposures Annex B. Exposures of the public and workers from various sources of radiation INTROdUCTION 1. In the course of the research and development for and the application of atomic energy and nuclear technologies, a number of radiation accidents have occurred. Some of these accidents have resulted in significant health effects and occasionally in fatal outcomes. The application of technologies that make use of radiation is increasingly widespread around the world. Millions of people have occupations related to the use of radiation, and hundreds of millions of individuals benefit from these uses. Facilities using intense radiation sources for energy production and for purposes such as radiotherapy, sterilization of products, preservation of foodstuffs and gamma radiography require special care in the design and operation of equipment to avoid radiation injury to workers or to the public. Experience has shown that such technology is generally used safely, but on occasion controls have been circumvented and serious radiation accidents have ensued. 2. Reviews of radiation exposures from accidents have been presented in previous UNSCEAR reports. The last report containing an exclusive chapter on exposures from accidents was the UNSCEAR 1993 Report [U6]. 3. This annex is aimed at providing a sound basis for conclusions regarding the number of significant radiation accidents that have occurred, the corresponding levels of radiation exposures and numbers of deaths and injuries, and the general trends for various practices. Its conclusions are to be seen in the context of the Committee's overall evaluations of the levels and effects of exposure to ionizing radiation. 4. The Committee's evaluations of public, occupational and medical diagnostic exposures are mostly concerned with chronic exposures of …