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Biomedical subjects

Tim J King

Publications and source records attributed to Tim J King.

4 recordsLinked to original sources

Efficient generation of transgenic pigs using equine infectious anaemia virus (EIAV) derived vector.

Traditional methods of transgene delivery in livestock are inefficient. Recently, human immunodeficiency virus (HIV-1) based lentiviral vectors have been shown to offer an efficient transgene delivery system. We now extend this method by demonstrating efficient generation of transgenic pigs using an equine infectious anaemia virus derived vector. We used this vector to deliver a green fluorescent protein expressing transgene; 31% of injected/transferred eggs resulted in a transgenic founder animal and 95% of founder animals displayed green fluorescence. This compares favourably with results using HIV-1 based vectors, and is substantially more efficient than the standard pronuclear microinjection method, indicating that lentiviral transgene delivery may be a general tool with which to efficiently generate transgenic mammals.

Animals↗

Immunohistochemical characterization of cloned lamb nephropathy.

Kidneys from lambs derived by nuclear transfer are frequently abnormal and are characterized by an enlarged pelvis and narrow medulla, consistent with lower urinary tract obstruction and development of variable hydronephrosis. The precise pathogenesis of this entity is unknown. Immunohistochemical staining for intermediate filaments was used to further characterize the lesions seen in this condition and was compared with age-matched control tissue. Major findings were upregulation of cytokeratin on damaged tubules, desmin and vimentin in undifferentiated mesenchyme, and smooth muscle actin in mesenchyme and on smooth muscle "collars" around dilated tubules. In addition, some cases showed reexpression of vimentin and desmin on proximal tubular epithelial cells. Taken together, these findings provide a valuable database for tracking the expression of intermediate filaments throughout renal development in sheep and have further characterized the nature of the response to injury by the developing kidney, a response that is characterized by proliferation of mesenchyme and both reexpression and upregulation of intermediate filaments within renal cells. In addition, the study has confirmed that the changes in cloned lamb nephropathy are established by day 85 of development.

Actins↗

Human cloning: can it be made safe?

There are continued claims of attempts to clone humans using nuclear transfer, despite the serious problems that have been encountered in cloning other mammals. It is known that epigenetic and genetic mechanisms are involved in clone failure, but we still do not know exactly how. Human reproductive cloning is unethical, but the production of cells from cloned embryos could offer many potential benefits. So, can human cloning be made safe?

Animals↗