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Biomedical subjects

A G Need

Publications and source records attributed to A G Need.

At least 73 records · Page 4Linked to original sources
PubMed1991

Effect of salt restriction on urine hydroxyproline excretion in postmenopausal women.

Fasting calcium and hydroxyproline excretion are related to fasting sodium excretion in postmenopausal women. We postulate that calcium excretion is sodium dependent and that hydroxyproline excretion is calcium dependent. Therefore, we sought to lower urinary hydroxyproline, which is a marker of bone resorption, by lowering urinary sodium. Fasting urine samples were obtained from 59 postmenopausal women before and after 2 to 7 days of dietary salt restriction. The urinary sodium-to-creatinine ratio fell from 16 to 7; calcium to creatinine, 0.30 to 0.26; and hydroxyproline to creatinine, 18.2 to 16.8. In the 28 subjects with starting sodium-to-creatinine ratios greater than 15, the hydroxyproline-to-creatinine ratio fell from 19.6 to 16.3. Salt restriction may be one way of reducing bone resorption in postmenopausal women, particularly in those whose sodium intake is high.

Aged↗
PubMed1990

Progressive cancellous bone loss in rats after adrenalectomy and oophorectomy.

Female Sprague-Dawley rats (n = 72), 6 months old, underwent either sham operation, oophorectomy, adrenalectomy, or combined oophorectomy and adrenalectomy (O&A). They were all maintained on normal saline ad libitum and 20 g/day 1.1% calcium chow. Nine weeks after operation, the trabecular bone volume of the distal femoral shaft was significantly lower (P less than 0.001) in the adrenalectomized (11.1%), oophorectomized (7.0%), and O&A (8.3%) animals than in sham-operated animals (19.8%). Eighteen weeks after operation, the trabecular bone volume in O&A animals had fallen to a mean of 3.8% (sham 17.0%), and the length of the femur had increased to 38.8 mm after O&A (sham 36.8 mm, P less than 0.01). O&A animals treated with 0.35 mg/kg/week nandrolone decanoate from 9 weeks postoperatively onward, had twice the femoral trabecular bone volume of untreated animals at 18 weeks (P less than 0.05). By contrast, no significant differences were found in vertebral body trabecular bone between any groups, including groups receiving treatment with androgens. We have found that, by 9 weeks after operation, adrenalectomy alone causes significant loss of metaphyseal trabecular bone, similar to the progressive loss seen after oophorectomy.

Adrenal Glands↗
PubMed1990

Malabsorption of calcium in corticosteroid-induced osteoporosis.

We have examined the relation between radiocalcium absorption and serum 1,25-dihydroxyvitamin D [1,25(OH)2D3] levels in a set of 60 postmenopausal women on corticosteroid therapy (29 with and 31 without vertebral compression fractures) and compared these results with those from 31 normal postmenopausal women age-matched with the "normal" corticosteroid-treated women. Radiocalcium absorption was a function of serum 1,25(OH)2D3 in both corticosteroid-treated groups and in the set as a whole, but the impaired calcium absorption in the corticosteroid-treated patients with osteoporosis was not accounted for by their slightly reduced serum 1,25(OH)2D3 levels. This apparent resistance to the intestinal action of 1,25(OH)2D3 was quantified by a Z score which expresses, in standard deviation units, the difference between the measured calcium absorption and that predicted from the 1,25(OH)2D3 level. The Z score was significantly reduced in the osteoporotic group. Vertebral mineral density (VMD) was measured by quantitative computed tomography in 43 of the corticosteroid-treated cases and in all the normal postmenopausal women; analysis by VMD yielded similar conclusions.

Adrenal Cortex Hormones↗
PubMed1990

Calcium and calcitriol therapy in osteoporotic postmenopausal women with impaired calcium absorption.

The effects of oral calcitriol (0.25 and 0.50 micrograms/d), together with calcium (1 g/d), on calcium absorption and bone resorption were measured in postmenopausal osteoporotic women with calcium malabsorption. Radiocalcium absorption was significantly improved and urinary hydroxyproline/creatinine excretion significantly reduced on both doses, but the higher dose caused an unacceptable incidence of hypercalcemia. In 49 patients treated for an average of 15 months with the lower dose, there was a nonsignificant gain in forearm bone mass of 0.4 +/- 0.3 mg/cm/mo (approximately 1/2% per annum) compared with a significant decrease in 17 untreated patients of 3.8 +/- 1.3 mg/cm/mo (approximately 5% per annum).

Absorption↗
PubMed1990

Relationship between plasma calcium fractions, other bone-related variables, and serum follicle-stimulating hormone levels in premenopausal, perimenopausal, and postmenopausal women.

The study comprises 186 untreated normal premenopausal, perimenopausal, and postmenopausal women in whom we measured serum follicle-stimulating hormone and a number of bone-related plasma and urinary variables. The calcium fractions in the plasma were calculated from the total calcium, albumin, globulin, anion gap, and bicarbonate concentrations. With a level of follicle-stimulating hormone within the reference range (up to 20 U/L) to define the premenopausal state, we confirmed previously reported menopausal rises in plasma calcium, phosphate, alkaline phosphatase, and bicarbonate, and in urinary calcium and hydroxyproline. However, inspection of the data, and t testing at different follicle-stimulating hormone criteria showed that these changes in bone-related variables did not generally occur until the level of follicle-stimulating hormone exceeded approximately 50 U/L. The plasma alkaline phosphatase level rose earlier than the other variables and was significantly elevated in subjects with follicle-stimulating hormone values above 30 U/L. The rise in plasma calcium was mainly a result of a rise in the ultrafiltrable fraction, which in turn was accounted for by rises in the ionized and complexed fractions, of which the complexed fraction was the most significant and proportionately the largest. The rise in the complexed fraction was accounted for by the increase in plasma bicarbonate.

Adult↗
PubMed1990

The reproducibility of bone-related biochemical variables in post-menopausal women.

Seventeen measured and derived bone-related biochemical variables were determined in 60 postmenopausal women on two occasions from 1 to 35 months apart. The coefficients of determination (r2) between the first and second observations were highly significant in respect of all measured and calculated variables except for anion gap, calculated complexed calcium, fasting urinary sodium:creatinine ratio and urinary phosphate:creatinine ratio. The variables with coefficients of determination which ranked highest include plasma alkaline phosphatase, albumin, globulins, calculated ionized calcium and fasting urinary corrected calcium:creatinine and hydroxyproline: creatinine ratios. They also showed marked individuality suggesting that changes within the conventional population based reference range possibly indicate significant physiological changes in metabolism. The critical difference for two results to be significantly different (P less than 0.05) was calculated from the total variation for each variable. We conclude that most of the measured and derived bone-related biochemical variables in fasting plasma and urine samples are sufficiently reproducible in postmenopausal women to be clinically and physiologically meaningful but that urinary sodium and phosphate are inconstant and probably dependent on the previous day's dietary intake.

Aged↗
PubMed1990

The relative contributions of age and years since menopause to postmenopausal bone loss.

We have estimated the relative contributions of age and menopause to forearm mineral density in 485 normal postmenopausal women up to age 75 yr. In 87 pairs matched for years since menopause, in which 1 member was below 61 yr and the other was 61 yr or older, the mean bone density was significantly lower in the older than in the younger subjects despite their identical years since menopause (P less than 0.001). Further analysis suggested a model for bone loss after the menopause which comprises a menopausal component of exponential type and an age-related component which is linear and starts in the mid-50s. According to this model, a 70-yr-old woman has lost 11% of her bone due to menopause and 18% as a function of age. Thereafter, the age-related function is dominant. Early menopause is associated with a self-limiting loss of bone which does not progress further until aging exerts its effect. The main conclusion is that the significance of early menopause as a risk factor for osteoporosis has been overstated.

Age Factors↗
PubMed1989

Cross-over study of fat-corrected forearm mineral content during nandrolone decanoate therapy for osteoporosis.

We have previously reported an increase in forearm bone mineral content (BMC) during therapy for osteoporosis with the anabolic steroid, nandrolone decanoate. However, it has recently been claimed that part of this increase is spurious, due to a decrease in forearm fat during the treatment. We have therefore analyzed the data from a cross-over study of the effects of this agent on 70 osteoporotic women, using the fat correction procedure supplied by the manufacturer of the forearm densitometer. There was a significant rise (p less than 0.001) in the mean fat-corrected BMC (BMC[fc]) on nandrolone decanoate (50 mg intramuscularly every 2 or 3 weeks) and a non-significant fall in mean BMC[fc] off the drug. The mean time-weighted rate of change in the fat-corrected value was +29 +/- 5 mg/cm/year on nandrolone decanoate and -5 +/- 5 mg/cm/year off nandrolone decanoate (p less than 0.001). Nandrolone decanoate produces a significant gain in forearm mineral content even after allowing for changes in forearm fat content during therapy.

Aged↗
PubMed1989

Treatment of malignancy-associated hypercalcemia with norethisterone: a case report.

Hypercalcemia is a common cause of morbidity in cancer patients. The mechanism of malignancy-associated hypercalcemia includes increased bone resorption and decreased renal calcium clearance which also occur in primary hyperparathyroidism. Norethisterone can inhibit bone resorption and has recently been shown to be effective treatment for mild hyperparathyroidism in post menopausal women. We report the successful use for the first time of norethisterone (5 mg daily) in a case of malignancy-associated hypercalcemia after other standard agents failed.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Improved method for calculating calcium fractions in plasma: reference values and effect of menopause.

Multiple linear regression analysis showed that total calcium was significantly and positively related to albumin, globulin, anion gap, and bicarbonate in plasma from 556 normal postmenopausal women. The residual constant of 1.21 mmol/L approximated the normal mean for ionized calcium in plasma. The coefficients derived from the multiple regression analysis were used to calculate ionized calcium from total calcium and ligand concentrations in a series of 105 clinical cases in whom ionized calcium was measured with the calcium electrode. The regression equation was y = 1.00x -0.0039 mmol/L, where x is measured and y calculated Ca2+ (r = 0.78, P less than 0.001). The protein-bound, ultrafiltrable, and complexed fractions of the calcium were also calculated for plasma from 69 normal young men, 66 normal young women, and 305 normal postmenopausal women. The increased plasma calcium in the postmenopausal group was accounted for by an increase in the complexed fraction, due to increases in plasma bicarbonate and anion gap.

Adult↗
PubMed1989

Effects of nandrolone decanoate and antiresorptive therapy on vertebral density in osteoporotic postmenopausal women.

Conventional antiresorptive therapy for osteoporosis can delay bone loss, but secondary inhibition of bone formation appears to prevent an increase in bone density. Recently, anabolic steroid therapy has been shown to increase total body calcium and forearm density in osteoporotic patients, perhaps by causing an increase in bone formation. It is not known if these agents affect vertebral density. We have measured vertebral mineral density in 71 postmenopausal osteoporotic women before and after treatment with either the anabolic steroid nandrolone decanoate or antiresorptive therapy. After a mean treatment period of 14 months, there was a mean increase of 20% in vertebral mineral density in the former group, and no significant change in the latter group. The difference in the time-weighted mean rates of change between the two groups was significant. The results suggest that nandrolone decanoate therapy increases bone formation.

Aged↗