Biomedical subjects

N Torpey

Publications and source records attributed to N Torpey.

3 recordsLinked to original sources

PubMed1999

Oligodendroglial gliomatosis cerebri: (1)H-MRS suggests elevated glycine/inositol levels.

Oligodendroglial gliomatosis cerebri is very rare. We describe 42-year-old woman who had low-grade oligodendroglial gliomatosis cerebri confirmed on stereotactic biopsy. The diffuse nature of the tumour was apparent clinically, neurophysiologically, on MRI and on proton magnetic resonance spectroscopy (MRS). She also had an isolated, false-localising partial seventh nerve palsy. MRS, of which there are no previous reports, suggested elevated glycine/inositol levels. This might be explained by the cell lineage from which the tumour arose.

Adult↗

PubMed1992

Function of maternal cytokeratin in Xenopus development.

Intermediate filaments are ubiquitous in eukaryotic cells, but their functions are poorly understood. The Xenopus oocyte contains both messenger RNA and protein products of cytokeratin and vimentin genes in non-overlapping arrays. The cytokeratin filaments contain dimers of the type I (acidic) subunit XLK3a(19), and the type II (basic) subunit XCK1(8), polymerized to form a cortical network. These are homologues of the human simple epithelial keratins 19 and 8, respectively. After the first few cell cycles following fertilization these filaments become restricted to the superficial cells of the blastula. We have depleted the oocyte's store of the type II cytokeratin mRNA by injecting antisense oligodeoxynucleotides (oligos) and studied the effect on embryonic development. As zygotic transcription does not commence until the late blastula stage, there are at least 9 hours in which to see the effect of loss of function of this mRNA. We report here that the cytokeratin filaments become depleted in the cortical cells of the embryo. As a result, there is a loss of the 'compacted' epithelial surface of the blastula, an inability to close a wounded surface and defective gastrulation.

Animals↗

PubMed1992

The role of intermediate filaments in early Xenopus development studied by antisense depletion of maternal mRNA.

The effects of depleting a maternal cytokeratin mRNA on the developing embryo are described. Cytokeratins are members of the intermediate filament family of cytoskeletal proteins, and are expressed in a cortical network of the superficial cytoplasm of the oocyte. After fertilisation, a new cortical network is built up, which comes to occupy only the most superficial cells of the blastula. The maternal cytokeratin mRNA is abundantly translated, both during oogenesis, and during oocyte maturation and after fertilisation. Depletion of the mRNA results in depletion of the cortical filaments at the blastula stage and leads to gastrulation abnormalities. We discuss the various possible control experiments required for antisense oligo depletion studies and the implications of these results for cytokeratin function.

Animals↗