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Biomedical subjects

G G Steel

Publications and source records attributed to G G Steel.

At least 163 records · Page 9Linked to original sources
PubMed1972

Cell proliferation during immunological perturbation in three transplanted tumours.

The cell population kinetics of 3 transplantable tumours has been studied under circumstances in which the tumour growth rate was modified by a disturbance of the immunological status of the host. In 2 cases a complete arrest of growth was achieved but in spite of this there was a barely significant change in the median intermitotic time of proliferating cells. The data indicate that growth retardation was associated with a reduction in the proportion of actively proliferating cells and the rate of cell production, with or without an increase in the absolute rate of cell loss.

Adenocarcinoma↗
PubMed1972

Thymidine labelling studies in a transmissible venereal tumour of the dog.

The cell population kinetics of the transmissible venereal tumour of the dog was studied at two different stages of tumour growth using the labelled mitoses technique. At the first stage the tumours were growing with a doubling time of about 4 days; at the second stage their growth rate was limited, probably by an immune reaction on the part of the host, to a doubling time greater than 20 days.Labelling of the tumour cells was found to be extremely heterogeneous throughout the tumour. Mitotic figures, however, were present in well labelled as well as in poorly labelled fields, suggesting that thymidine did not reach all regions of the tumour nodules. The data were therefore analysed assuming that the cells in well labelled areas were representative of the total cell population in the neoplasm. The timing of the cell cycle was found to be similar in the rapidly growing tumours and in those growing more slowly. It is concluded that the slowing of growth was due to a considerable increase in the rate of cell loss as a result of the immune reaction.

Animals↗
PubMed1971

Cell population kinetics of a spontaneous rat tumour during serial transplantation.

Studies have been made on the growth and cell population kinetics of a spontaneous rat mammary fibroadenoma and of 10 successive transplantation passages. The volume doubling time decreased from about 30 days in the primary tumour and first two transplants to 1·7 days in the tenth transplant. This acceleration was accompanied by a considerable shortening of the mitotic cycle and of its S and G(1) phases but without change in the proportion of time spent in S. There was also a reduction in the apparent extent of cell loss and a considerable increase in the growth fraction. Histological changes were noted and studies by feulgen densitometry indicated a considerable shift in ploidy from hyperdiploid to hypertetraploid. The results constitute a detailed example of the effect on tumour growth kinetics of serial transplantation.

Adenofibroma↗