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R B Burnet

Publications and source records attributed to R B Burnet.

9 recordsLinked to original sources

Bone densitometry in clinical practice: longitudinal measurements at three sites in postmenopausal women on five treatments.

We report sequential changes in bone mineral density (BMD) at the forearm, hip and spine in 340 consecutive postmenopausal women referred by 103 general practitioners and six specialists, and who were either untreated or being treated with calcium, estrogen, norethisterone or calcitriol for a median period of 25 months (range 11-52). The mean annual rate of change in BMD at the three sites was: 1.39% in 44 women on norethisterone; 0.94% in 107 women on estrogen (both p < 0.001); 0.24% (not significant) in 52 women on calcitriol; -0.53% in 92 women on calcium; and -1.06% in 45 women on no treatment (both p < 0.01). The mean annual rate of change at the three sites in the 295 treated women was 0.43%, which was significantly positive (p < 0.001) and was 1.49 percentage points more positive than in the untreated women (p < 0.001). The greatest mean difference between treated and untreated patients was seen at the forearm, where it was 2.16 percentage points (p < 0.001). This was significantly greater than the difference at the femoral neck (1.21 percentage points (p = 0.037)) and lumbar spine (1.10 percentage points (p = 0.044)). The data did not change significantly after correction for age, years since menopause or baseline BMD. Those who started the treatments at baseline gained bone faster than those who were continuing on existing therapies, but this difference was not significant at any site. In the hormone- and calcitriol-treated groups, there was no significant difference between those who had a calcium supplement and those who did not. We conclude that the effects of treatment on BMD in clinical practice are comparable to those predicted from clinical trials, that there are significant differences between the responses to treatment at different sites and that the forearm appears to be the most sensitive site, in this series at least.

Absorptiometry, Photon↗

Premenstrual syndrome and spironolactone.

A double blind placebo controlled randomized cross over study was conducted to assess the response to spironolactone by patients suffering from 'Premenstrual Syndrome'. Somatic and neuropsychiatric symptoms were self-assessed daily and a total score was calculated for each symptom for the 14 days prior to menstruation. No significant difference was noted for the symptoms assessed on or off spironolactone. The levels of oestradiol, progesterone and prolactin showed no changes from the first to the second half of the cycle. In those patients who did respond to spironolactone, a significant difference in androgen levels from the follicular to the luteal phase of the cycle prior to treatment was demonstrated. Significant differences in androgen levels from the follicular to the luteal phase of the menstrual cycle may therefore be an important determinant in predicting those patients with premenstrual syndrome likely to respond to spironolactone therapy.

Androgens↗

Spironolactone as a source of interference in commercial digoxin immunoassays.

Eight commercial digoxin immunoassay methods were tested in 17 subjects taking spironolactone (but not digoxin) to evaluate cross-reactivity from parent drug and/or metabolites. Four of these methods showed significant (up to 1.9 nmol/L) and variable "apparent digoxin" concentrations, despite the absence of digoxin in the drug regimen. The results suggest that clinical laboratories require a knowledge of their method with respect to spironolactone-related cross-reactivity and should exercise caution when interpreting digoxin results where spironolactone is coadministered. Further, the presence of concurrent renal and/or hepatic impairment could delay clearance of spironolactone metabolites (as well as digoxin metabolites and endogenous substances) and further distort a genuine digoxin result.

Adult↗

Hirsutism.

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Female↗

Intentional radioiodine ablation in Graves' disease.

In a series of 50 cases of Graves' disease qualifying for therapy with radioiodine, "ablative" doses of radioiodine resulted in hypothyroidism in 92% of cases at six months. Hypothyroidism was treated by thyroxine or tri-iodothyronine replacement therapy. Rapid responses and predictable outcome were regarded as important advantages. Intentional ablation is particularly convenient in situations where clinical and biochemical follow-up may be difficult. Further follow-up studies are needed to determine whether ablative therapy is the treatment of choice in all cases of Graves' disease.

Administration, Oral↗

Selective impairment of growth hormone response to physiological stimuli.

In a consecutive group of 25 children with defective growth being evaluated for growth hormone deficiency, EEG-monitored slow-wave sleep provided discriminatory serum growth hormone responses equivalent to those obtained by arginine and insulin-hypoglycaemia provocation. Exercise was less effective but was able to provide a useful screening test. In 2 subjects with abnormal physiological but normal pharmacological serum growth hormone responses, therapeutic administration of growth hormone in one resulted in a significant growth increment, whereas in the other, advanced epiphyseal maturity precluded adequate evaluation. A normal growth hormone response to a pharmacological stimulus does not exclude a therapeutic response to human growth hormone.

Adolescent↗