Biomedical subjects

J Mansbridge

Publications and source records attributed to J Mansbridge.

23 records · Page 2Linked to original sources

PubMed1982

Epidermal characteristics related to skin cancer susceptibility.

We have compared the basal cell labeling index and cellular architecture in samples of epidermis removed by vacuum blistering from people with or without a personal history of skin cancer. Donors with no family history of skin cancer showed a basal cell labeling index of 5.5% with a standard deviation of 1.3%. Those not personally affected but with a family history gave 4.1% +/- 0.4% but among cancer patients the value was approximately doubled to 11.5% +/- 2.7%. The proportion of cells replicating was reduced after ultraviolet irradiation, with a D0 of 40 J/m2 for UVB but no difference could be demonstrated between individuals with or without a history of skin cancer.

Autoradiography↗

PubMed1981

Frequency of U.V. induced protein-DNA crosslinks in cell lines of different sensitivities.

We have measured U.V.-induced protein-DNA crosslinking in two cultured human cell lines of different sensitivities. Using a previously published method, involving SDS-protein precipitation, we obtained a biphasic response with an initial slope of 0.6 per cent DNA J-1 m2 up to 50 J m-2 and a second-phase slope of 0.12 per cent DNA J-1 m2 with a background of 22 +/- 13 per cent. Rigorous washing of SDS-protein precipitates reduced background binding to about 5 per cent with a linear U.V. effect up to 100 J m-2 of 0.038 per cent DNA J-1 m2. Binding was judged to be covalent on the grounds of stability to boiling and represented 4.1 crosslinks pg DNA-1 J-1 m2 or 60 crosslinks cell-1 J-1 m2. Similar results were obtained for both cell lines. We conclude that the differences in U.V. survival between cell lines is not related to the extent of protein-DNA crosslinking. We have been unable to detect repair of these lesions in either cell line.

Cell Line↗

PubMed1976

Resistance of human melanoma cells to ultraviolet radiation.

A series of five human melanoma cell lines has been demonstrated to be highly resistant to ultraviolet (UV) radiation, with a D0 of 400 ergs/sq mm. Melanotic melanoma cells were found to increase their production of melanin following UV radiation, whereas some amelanotic cells did not. Melanotic and amelanotic melanoma cell lines exhibited the same UV resistance; melanoma and nonmelanoma cells formed the same numbers of thymine dimers at a given UV dose. These data imply that melanin does not play a major role in protecting DNA of melanoma cells against UV damage in culture. The rates of removal of thymine dimers from DNA of melanoma cells were comparable to those in UV-sensitive, nonmelanoma cell lines, so that rapid excision repair does not explain UV resistnace in the melanoma cells. No DNA strand breakage was detected in a melanoma cell line at moderate UV doses.

Cell Line↗

PubMed1974

The fractionation of adenosine-rich oligoribonucleotides on polyethyleneimine-cellulose.

After combined pancreatic and T(1) ribonuclease treatment of RNA, a characteristic series of products of the type A(n)N are obtained, where N can be any of the four ribonucleosides. Depending on whether phosphatase treatment is used before the addition of labelled phosphate at the 5'-terminus with bacteriophage phosphokinase, the labelled oligonucleotides obtained may or may not possess a phosphate group at the 3'- as well as the 5'-end. The behaviour of these characteristic products after electrophoresis on cellulose acetate strips followed by chromatography on polyethyleneimine-cellulose thin-layer plates was examined.

Adenine Nucleotides↗

PubMedDate not supplied

Ways men and women lead.

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Administrative Personnel↗