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Biomedical subjects

D H Marshall

Publications and source records attributed to D H Marshall.

At least 19 recordsLinked to original sources
PubMed1992

Bisphosphonate space measurement in Paget's disease of bone treated with APD.

The bisphosphonate space (BPS) is a quantitative measurement of skeletal uptake of 99mTc-HMDP. We measured BPS in 36 patients with Paget's disease of bone, both before and 6 months after treatment with intravenous APD (disodium pamidronate) infusions. BPS fell after treatment, but proportionally less than serum alkaline phosphatase (ALP) and fasting urinary hydroxyproline/creatinine (HYPRO). There was no dose-response relationship between the dose of APD given and the percentage reduction in ALP and HYPRO at 6 months. Log dose of APD/pretreatment BPS, however, predicted the percentage reduction in ALP and HYPRO very well, and from the respective regression equations it was possible to predict the dose of APD needed to achieve normal values of ALP and HYPRO. In the 10 patients who achieved a normal ALP and 9 patients a normal HYPRO after more than 6 months treatment with APD (range 7-18 months), the predicted dose of APD agreed closely with the actual dose. In conclusion, our data support the idea that log dose APD/pretreatment BPS is a valid predictor of biochemical response in Paget's disease.

Alkaline Phosphatase↗
PubMed1979

Vitamin D and magnesium absorption in man.

1. The effects of vitamin D and its hydroxylated derivatives on calcium and magnesium absorption have been examined in 47 balance studies on patients with various disorders of calcium or bone metabolism. 2. Vitamin D significantly increased the mean net absorption of calcium and also the calcium balance. The mean net absorption of magnesium was also significantly increased although the rise was much less than that of calcium and the mean magnesium balance was unaffected. 3. It is suggested that the slight effect of vitamin D on magnesium absorption may be incidental to its stimulation of active calcium transport, since the latter system has weak affinities for other alkaline earth ions including strontium, barium and magnesium.

Absorption↗
PubMed1979

Prevalence, pathogenesis and treatment of post-menopausal osteoporosis.

About 11% of post-menopausal women with wrist fractures have spinal osteoporosis with compressed vertebrae, and about 25% of postmenopausal osteoporosis patients have had a wrist fracture. The estimated prevalence of post-menopausal spinal osteoporosis is 4% of the female population at age 60 and about 8% at age 80. Osteoporotic patients have lower plasma oestrone and androstenedione levels, lower calcium absorption and higher urinary hydroxyproline than matched controls. Of six treatments tested in three different ways, the least successful were vitamin D2 and 1 alpha-OHD3 and the most successful were hormones with or without 1 alpha-(OH)2D3 and calcium supplements. Calcium and vitamin D given in combination occupied an intermediate position.

Aged↗
PubMed1979

Calcium requirement and calcium therapy.

The mean calcium requirement of normal adults has been estimated from 212 calcium balances on 84 normal subjects and found to be 578 mg. The calcium allowance required to ensure that 95% of normal adults are in calcium balance is about 900 mg. Calcium requirement is relatively higher than that of phosphorus or magnesium because plasma calcium--and therefore urine calcium--is maintained at the expense of the skeleton in the presence of calcium deficiency, whereas plasma phosphate and magnesium--and therefore urine phosphate and magnesium--fall on phosphorus and magnesium deficient diets. Calcium requirement appears to rise at the menopause, and postmenopausal bone loss can be reduced by calcium supplements. In postmenopausal osteoporosis, the severe negative calcium balance can be corrected by giving calcium or calcium and vitamin D, but vitamin D alone is not beneficial. Similarly, bone loss, height loss and further vertebral compression can be reduced by calcium or calcium and vitamin D but not by vitamin D alone.

Bone Diseases↗
PubMed1978

Thermal transformation of cholecalciferol between 100--170 degrees C.

Cholecalciferol is transformed, irreversibly, to pyrocholecalciferol and isopyrocholecalciferol. The rate constant, as a function of temperature, for this transformation from the equilibrium mixture of cholecalciferol and precholecalciferol has been determined for temperatures between 100--170 degrees C and is slower than the precholecalciferol-cholecalciferol interconversion. The ratio of rates of production of pyro to isopyro derivatives is 2:1 throughout.

Chemical Phenomena↗
PubMed1978

The relation between plasma androstenedione, plasma oestrone and androstenedione to oestrone conversion rates in post-menopausal women with and without fractures.

1. Plasma androstenedione, plasma oestrone and the conversion of plasma androstenedione into oestrone were measured in 19 post-menopausal women without fractures (six of them oophorectomized) and 18 with vertebral or femoral neck fractures (four of them oophorectomized). 2. In the series as a whole, the main determinant of the plasma oestrone level was the plasma androstenedione concentration. Only in the small oophorectomized group did the variation in conversion rate make a significant contribution to the variation in plasma oestrone. 3. The conversion rates were not different as between non-fracture and fracture cases but the mean plasma androstenedione and oestrone concentrations were lower (though not significantly) in the latter.

Adrenal Glands↗
PubMed1978

The relation between plasma androstenedione and oestrone levels in untreated and corticosteroid-treated post-menopausal women.

Plasma oestrone (E1) and androstenedione (A) were measured in 96 untreated and 18 corticosteroid-treated post-menopausal women. Levels of both hormones were consistently lower in the steroid-treated cases, presumably due to suppression of ACTH secretion. There was a clear relationship between A and E1 levels in both groups and when the data were pooled they formed a continuous series with a curvilinear relationship going through the origin. This relationship could be described by an equation based on Michaelis-Menten kinetics, suggesting that the rate of A to E1 conversion is an inverse function of the plasma androstenedione level. The main determinant of plasma E1 was plasma A; body weight and age were of subsidiary importance. Secondary oestrogen deficiency may be a factor in the genesis of steroid-induced osteoporosis in post-menopausal women and oestrogen therapy may be indicated in this group of patients.

Adrenal Cortex Hormones↗
PubMed1978

Risk factors in calcium stone disease of the urinary tract.

The concept that calcium stone formation may be explained on the basis of a number of risk factors is developed. The main risk factors involved are shown to be calcium, oxalate, pH, acid mucopolysaccharides and uric acid. A method is described for calculating and combining the individual risk factors into a measure of the "relative probability" of forming stones (PSF). PSF values are generally lower in normal subjects than in stone-formers. Amongst the normals, PSF values are lower in children and women than in men. Recurrent stone-formers have the highest PSF values and these correlate well with the severity of the diseases as defined by the stone episode rate of the patient. Single stone-formers have PSF values intermediate between those of normal men and those of recurrent stone-formers.

Adult↗
PubMed1978

Reversal of betamethasone-induced inhibition of intestinal calcium absorption by 1alpha-hydroxycholecalciferol.

The intestinal absorption of calcium has been studied in conscious, unstressed pigs, using a modification of the double isotope technique. The oral administration of betamethasone (1 mg/day) to four pigs (25--33 kg) for 4 weeks reduced the calcium absorption coefficient, calculated after the intravenous and oral administration of 47Ca2+, by a mean value of 66%. The oral administration of 1alpha-hydroxycholecalciferol (2 microgram/day) in combination with beta-methasone (1 mg/day) for a further 4 weeks returned the absorption coefficient to the control value.

Animals↗
PubMed1977

Plasma androstenedione and oestrone levels in normal and osteoporotic postmenopausal women.

Plasma androstenedione and oestrone concentrations were measured in 72 postmenopasual women. The women included some who had undergone oophorectomy, some with osteoporosis, and normal controls; they were matched for years since menopause. Both hormone concentrations were significantly reduced in the women with osteoporosis. The women who had undergone oophorectomy had hormone concentrations intermediate between the normal and osteoporotic values. Oestrogen deficiency secondary to low androstenedione levels is a major risk factor in postmenopausal osteoporosis, and may be caused by failure of ovarian stromal androgen secretion or some abnormality in the pituitary-adrenal axis.

Adult↗
PubMed1977

Seasonal variations in the composition of urine from normal subjects: a longitudinal study.

The volume, pH and composition of 24-h urine samples, collected by 13 healthy male adults, were followed over a period of one year. Significant and systematic variations in urine pH, calcium, phosphate, oxalate, uric acid, potassium and magnesium were observed. A significant but non-sinusoidal variation in sodium excretion was found but there were no significant changes in urinary volume, creatinine or hydroxyproline. Many of the observed changes could be attributed to variations in the pattern of food consumption throughout the year but calcium, phosphate and oxalate were exceptions in that seasonal variations in these parameters appeared to be due to the effects of sunlight (or vitamin D) rather than to the diet.

Adult↗
PubMed1977

The effect of 1alpha-hydroxyvitamin D3 with and without oestrogens on calcium balance in post-menopausal women.

Balance studies were performed in thirty-three post-menopausal women (all but five having vertebral crush fractures or femoral neck fractures) in the basal state and on treatment with 1alpha-hydroxyvitamin D3 and/or oestrogenic hormones. The results suggest that the effectiveness of oestrogen therapy is limited by calcium malabsorption and the effectiveness of 1alpha-hydroxyvitamin D3 is limited by oestrogen deficiency. The best results were obtained with combined therapy to remedy what appears to be two distinct deficiencies. To minimize the risks of hypercalcaemia and the possible risks of hormone therapy, we suggest that the treatment of choice in post-menopausal osteoporosis may be 1alpha-hydroxyvitamin D3 1microgram daily and ethinyloestrodiol 25 microgram daily for 3 weeks in every 4. Patients on a low dietary intake of calcium should probably be given calcium supplements. With this regimen, it should not be necessary to screen patients initially for calcium malabsorption or oestrogen deficiency because the majority of patients present with a combination of the two factors.

Calcium↗