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Biomedical subjects

A P Brock

Publications and source records attributed to A P Brock.

8 recordsLinked to original sources

An in vitro study comparing the cytotoxicity of three platinum complexes with regard to the effect of thiol depletion.

The cytotoxicity of three platinum complexes, cis-diamminedichloroplatinum(II) (cis-platin), cis-dichloro-trans-dihydroxy-cis-bis (isopropylamine) platinum(IV), (CHIP) and diammine (1, 1-cyclobutane-dicarboxylato) platinum(II) (carboplatin) on Chinese Hamster ovary (CHO) and mouse sarcoma RIF-1 cells cultured in vitro has been compared. The tumour cell line was much more sensitive to the cytotoxic action of the three agents compared to the CHO cell line. CHIP and carboplatin gave similar dose-response curves, both being much less toxic than cis-platin. The effect of thiol modification on platinum toxicity was also investigated. Substantial reduction in the intracellular non-protein sulphydryl content markedly enhanced the cytotoxicity of CHIP but had much less effect on carboplatin and cis-platin. Thiol depletion by diethylmaleate had a negligible effect on cis-platin toxicity.

Animals↗

Pretibial myxoedema: stimulation of mucopolysaccharide production of fibroblasts by serum.

We have shown that sera from normal individuals and from patients with pretibial myxoedema contain a factor which simulates mucopolysaccharide biosynthesis in normal human skin fibroblasts cultured in vitro. This factor was present in larger amounts in sera of patients with pretibial myxoedema. The role of growth stimulating factors in serum is reviewed and a hypothesis is put forward that the fibroblast stimulating factor is somatomedin and that its presence in increased amounts in thyroid disease may lead to pretibial myxoedema.

Acetylgalactosamine↗

An improved method of assessing topical corticosteroid activity.

Topical application of ointment bases causes varying degrees of epidermal thickening in guinea-pigs. This is reproducible and can be accurately measured. Suppression of these changes was produced by addition of beta-methasone 17-valerate, fluocinolone acetonide, fluocinonide and hydrocortisone acetate. The inhibitory effect of these steroids was related to the type of corticosteriod, its concentration and the ointment base. The effect was still evident at extremely high dilutions of the steroids and could be measured at concentrations as low as 5 X 10(-5) % of fluocinonide in FAPG. This technique has the merits of being reproducible, sensitive and accurate. It should find a place among existing methods in assaying the efficacy of topical corticosteroids and in aiding in the selection of bases most suitable for formulation of these preparations.

Administration, Topical↗