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P M Perry

Publications and source records attributed to P M Perry.

At least 19 recordsLinked to original sources
PubMed1992

The optimum pressure of oxygen for radiotherapy of a mouse tumour.

Our previous studies have shown that there is more regrowth delay in mammary tumours irradiated in C3H mice after 25 Gy when breathing normobaric oxygen than in those breathing air, as might be expected. However, in both cases this radiation response was reduced in anaesthetized animals in comparison with unanaesthetized control mice, when a time interval of only 10 min was allowed after anaesthesia. After 25 min, however, the response in air returned to the control level and the oxygen group now showed significantly more radiosensitization. We have now found that when tumour-bearing mice were exposed to different pressures of oxygen for that 25-min period after the induction of anaesthesia, before the tumours were treated with 25 Gy, there was even more regrowth delay with 2 atm pressure than 1, but that there was no further advantage from using 3 atm pressure of oxygen. Our data suggest that 2 atm may be the optimal pressure to use in anaesthetized mice and there is even a small benefit from using this pressure in unanaesthetized animals for a transplanted C3H mammary tumour.

Anesthesia↗
PubMed1990

Measured intake and excretion patterns of naturally occurring 234U, 238U, and calcium in humans.

The normal dietary and fluid intake and urinary and fecal excretion of 234U and 238U were determined in humans under strictly controlled conditions in the Metabolic Research Ward at Hines Hospital. These values formed the basis of the metabolic balances of these uranium isotopes. The major pathway of 234U and of 238U excretion was via the intestine while the urinary 234U and 238U were very low, averaging 2% of the total excretion. The uranium balances were roughly in equilibrium. These data were used in combination with measurements of tissue concentrations of uranium from nonoccupationally exposed humans to calculate steady-state uptake factors for environmental exposure to uranium isotopes during baseline conditions of a normal dietary intake.

Animals↗
PubMed1989

Variation of tumour radiosensitivity with time after anaesthetic.

Transplanted C3H mouse mammary tumours were given single doses of X irradiation in air or oxygen at 1 atmosphere (atm) with or without anaesthesia of the recipient mice by ketamine and diazepam. The radiation response to single doses of 25 Gy was determined in terms of the time taken to reach 3.5 times the treatment volume. Under all conditions there was more growth delay in tumours irradiated in pure oxygen than in air. In both air and oxygen, the radiation response for anaesthetized animals tended to fall below the level for non-anaesthetized ones when only 10 min had elapsed after the administration of anaesthesia. After 25 min, the response in air was back to the level for the non-anaesthetized animals but the oxygen group now showed significant sensitization compared with the oxygen without anaesthetic group. After 40 min, the air group now showed slight sensitization and the oxygen group still showed significant sensitization by the anaesthetic. These results demonstrate the importance of the time interval between anaesthesia and irradiation of mouse tumours.

Adenocarcinoma↗
PubMed1989

Familial breast cancer and the association with colonic carcinoma.

A relationship between breast and colonic cancer has been suggested so we looked at the incidence of colonic carcinoma in the relatives of familial and sporadic breast cancer patients. We found that there is an increased incidence of colonic cancer in the relatives of familial breast cancer patients as compared with the relatives of sporadic breast cancer patients. This risk was higher in men than women (P less than or equal to 0.05). The relatives of familial breast cancer patients are a high risk group for developing colonic carcinoma, and would benefit from colonic screening.

Breast Neoplasms↗
PubMed1988

Familial breast cancer.

Familial breast cancer is important because of all the known risk factors associated with developing the disease. The one with the most predictability is a positive family history. It is also important because a family history causes anxiety in the families concerned, and young women will often ask their chance of developing the disease. This form of breast cancer accounts for 10% of causes and has factors that distinguish it from the sporadic variety. Relatives of familial breast cancer patients are not only at an increased risk of developing the disease (if female) but also of developing other tumours especially colonic.

Adult↗
PubMed1988

Modulating the oxygen tension in tumours by hypothermia and hyperbaric oxygen.

Hypothermia is associated with reduced metabolism of tissues and especially reduced oxygen consumption by tumours. If the blood supply to a hypothermic tumour can be maintained then the hypoxic fraction of cells should be reduced and the radiation response increased. This hypothesis has been tested with radiation under hyperbaric oxygen and increased tumour response has been demonstrated.

Adenocarcinoma↗