D. R. Appleton

Learn More
Verapamil increases the sensitivity of primary human colorectal carcinoma tissue to vincristine The inherent resistance of human solid tumours to cancer chemotherapy is a major problem in medical oncology. Experimentally, in cell lines, the resistance phenomena studied are often induced by a process analogous to the induction of antibiotic resistance in(More)
When symmetrical 1,2 dimethylhydrazine was administered to rats by weekly s.c. injection, 37% of the animals had developed small intestinal carcinomas after 21-27 weeks. These lesions were largely localized to duodenum and upper jejunum. At the same time there was a diffuse crypt hyperplasia in the jejunum which affected all the treated animals, not just(More)
A method is described enabling the direct measurement of vincristine resistance in intact tissues in vivo by morphological study. Using the metaphase arresting properties of the drug, counts were made of escaping anaphase and telophase mitotic figures at a range of doses. The proportion of post-metaphase mitotic figures is called the post-metaphase index(More)
We have measured mitotic indices and 3H-thymidine-labelling indices for the colonic epithelial tumours induced in rats by the administration of dimethyl-hydrazine (DMH). The fraction-of-labelled-mitoses (FLM) technique has been used to estimate the duration of the cell-cycle phases. In general, mitotic and labelling indices in the tumours are similar to(More)
In cell kinetic experiments, as in many other branches of biological science, we often sample at various stages of an experiment: we may for example take a sample of animals, then from each study a sample of sites, and from each site take replicate observations. This sampling process can be optimized to give maximum precision to an estimated quantity, but(More)
Mucosal explants were prepared from the colons of normal rats and from the non-neoplastic colonic mucosa of rats which had been treated chronically with the intestinal carcinogen dimethylhydrazine. They were maintained in an organ culture system which permitted survival up to at least 25 days. Morphological preservation of the mucosa was excellent up to 6(More)
Administration of 1,2 dimethylhydrazine (DMH) to rats by weekly s.c. injections causes the development of multiple epithelial tumours of the large bowel. These appear to arise as localized dysplastic abnormalities in hitherto apparently morphologically normal crypts. This study was undertaken in order to examine cell proliferation in such apparently normal(More)
Post-operative pain is frequently measured by a visual analogue scale (VAS). The most common methods for analysing such data are the so-called time-by-time method and repeated measures analysis of variance. In the first, due to correlation between time points, successive tests are not independent and cannot measure the treatment effects over time. In the(More)
A morphological method has been developed allowing measurement of the effect on intestinal epithelia of vincristine. In routinely prepared tissue sections the proportion of mitotic events progressing beyond metaphase is counted by microscopy. When estimated over a range of doses of vincristine this post-metaphase index (PMI) can be used to compare the(More)
In this article discussion is continued of the case where the response variable is continuous and the explanatory variable is discrete. Two particular situations are covered: the response variable survival time and the explanatory variable dichotomous: and the response variable continuous (but not survival time) and the explanatory variable discrete (but(More)