Biomedical subjects
Publications and source records attributed to R C Bonney.
Our study indicates that by using data obtained from the Model 3000 Echo-Oculometer, 93% of eyes receiving intraocular lenses will have an optimal visual acuity which will differ by less than three diopters from that calculated. With oscilloscopic control of the end points, the Echo-Oculometer provided good inter-observer reproducibility and low variability.
Circulating levels of oestrone and progesterone were measured by radioimmunoassays in plasma samles from 5 female owl monkeys on 60 consecutive days. Both steroids exhibited cyclic fluctuations and based on nadir to nadir intervals the ovarian cycle was estimated to be 15.92 +/- 0.26 days. Levels of oestrone and pregnanediol-3 alpha-glucuronide were also measured in daily urine samples. The fluctuations of urinary steroids reflected those observed in plasma. Ketamine sedation had no effect on the length of the cycle. Peak values of plasma progesterone and oestrone were 250.48 +/- 11.37 and 3.59 +/- 0.066 ng/ml respectively. There was no clear hormonal distinction between the follicular and luteal phase of the cycle in these owl monkeys.
Prolactin receptors were identified and partially characterized in the mammary gland of the rat. The binding of 125I-labelled ovine prolactin to a subcellular particulate fraction of rat mammary gland decreased between days 30 and 100 of age. Over the same period, binding to the liver increased and there was a significant negative correlation between prolactin binding in the two tissues. Binding to the mammary gland was low during pregnancy, increased in early lactation and declined after the litters were weaned. Binding to the liver was lower during lactation than during pregnancy or the period after weaning suggesting that tissue-specific factors may operate in the control of this receptor. In virgin rats, prolactin binding by the mammary gland was increased by oestrogen. This effect was blocked by hypophysectomy and partially restored by replacement therapy with prolactin. Hypothyroidism and treatment with progesterone also reduced the response to oestrogen. The maintenance of prolactin binding by the mammary gland of lactating rats depends on the presence of the ovaries and pituitary, thyroid and adrenal glands. Examination of the ratio epithelium: stroma suggests that prolactin acts by increasing the number of epithelial cells in the mammary gland and that thyroid, adrenal and ovarian hormones modulate the number of receptors per cell.
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The uptake and metabolism of 3H-oestradiol by breast tumour tissue was studied in three postmenopausal women before, after 1 week of treatment with ethynyl-oestradiol (EE, 10 micrograms/day) and again two weeks later after treatment with medroxyprogesterone acetate (MPA, 500mg/day, i.m.). Treatment with EE reduced the tissue: plasma gradients for both 3H-oestradiol and 3H-oestrone and little further change in these ratios occurred after MPA treatment. The proportion of oestrogen present as 3H-oestrone increased in tumours from 2/3 women after treatment with MPA but not EE, although no increase in the activity of oestradiol 17 beta-hydroxysteroid dehydrogenase (E2DH) was detected. Plasma and tissue concentrations of 5-androstenediol, dehydroepiandrosterone and dehydroepiandrosterone sulphate were all reduced after MPA treatment. The results from this study show that treatment with EE and MPA can reduce the uptake of oestradiol by breast tumours. No increase in E2DH activity was detected but it is possible that MPA influences other enzymes involved in oestradiol metabolism.