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Biomedical subjects

A G Need

Publications and source records attributed to A G Need.

At least 91 records · Page 5Linked to original sources
PubMed1988

The relation between forearm and vertebral mineral density and fractures in postmenopausal women.

Vertebral and forearm mineral density (VMD and FMD, respectively) were determined in 124 postmenopausal women with no crushed vertebrae or peripheral fractures, 51 who had sustained peripheral fractures only since the menopause, 62 with vertebral compression(s) only and 75 with both types of fracture. There was a very significant correlation between the two measurements in the whole set. The scatter could not be accounted for by methodological error but was partly accounted for by body weight, since VMD was related to body weight and FMD was not. Whatever criterion was used for the diagnosis of osteoporosis (whether fracture or density) the percentage of misclassified cases was very similar by the two methods. However, VMD was relatively more reduced than FMD in vertebral fracture cases and FMD was marginally more reduced than VMD in peripheral fracture cases. There is little to choose between vertebral and forearm density in the diagnosis of osteoporosis but vertebral densitometry is slightly superior to forearm densitometry in describing the severity of osteoporosis in vertebral fracture patients.

Body Weight↗
PubMed1988

Calcium and osteoporosis.

The loss of bone which starts at the menopause is self-limiting (exponential) and possibly mainly trabecular. It merges into an age-related linear loss of bone which is probably mainly cortical. The menopause is associated with a rise in obligatory urinary calcium loss resulting from an increase in the filtered load of calcium which may be due to the complexed fraction. The dependence of the urinary hydroxyproline on the urinary calcium and sodium suggests that the bone resorption is a response to calcium losses rather than a primary event. In osteoporotic women, there is a further increase in filtered load of calcium and obligatory calcium loss, frequently coupled with malabsorption of calcium. Urinary hydroxyproline can be suppressed by calcium administration in those with normal absorption and by calcitriol in those with calcium malabsorption. It is known that calcium deficiency causes osteoporosis in experimental animals, but there is controversy about the role of calcium deficiency in the pathogenesis of human osteoporosis. Calcium supplementation inhibits cortical bone loss in postmenopausal women but there is some doubt as to whether it can inhibit trabecular bone loss in women close to the menopause. This may be partly a matter of dose, formulation and time of administration.

Bone Resorption↗
PubMed1988

Biochemical effects of calcium supplementation in postmenopausal osteoporosis.

Although calcium supplements are widely used in the treatment of osteoporosis their beneficial effect is not conclusively established. The biochemical effects of a calcium supplement (1 g/d) given for between 6 and 36 months were studied in 20 postmenopausal osteoporotic women who had normal calcium absorption. The mean fasting urinary hydroxyproline/creatinine ratio decreased from 0.024 +/- 0.002 to 0.016 +/- 0.001 (P less than 0.005) indicating a significant reduction in bone resorption. The mean plasma alkaline phosphatase fell from 85 +/- 4 U/l to 73 +/- 3 U/l (P less than 0.005), probably representing a secondary reduction in bone formation following the inhibition of bone resorption. There was no significant change in calcium absorption. These results support the concept that calcium supplementation is useful in the treatment of postmenopausal osteoporosis.

Alkaline Phosphatase↗
PubMed1987

Effects of nandrolone decanoate on forearm mineral density and calcium metabolism in osteoporotic postmenopausal women.

Although anabolic steroids have been used for many years to treat osteoporosis there is little available evidence about their efficacy or mode of action. These agents have recently been shown to produce an increase in total body calcium and bone density and it has been suggested that they stimulate bone formation. In this study 27 osteoporotic postmenopausal women were given 50 mg of nandrolone decanoate intramuscularly, every 2 or 3 weeks for 3 months, and the changes in forearm mineral density, fasting plasma, and urinary calcium, urinary hydroxyproline, and radiocalcium absorption were measured. Associated with a rise in forearm mineral density was a significant fall in fasting urinary calcium, but no significant change in fasting urinary hydroxyproline. The plasma calcium and phosphate fell significantly and there was a significant rise in the renal tubular reabsorption of calcium and a fall in the renal tubular reabsorption of phosphate. In a subset of 22 patients there was a significant rise in radiocalcium absorption. The results are consistent with the concept that nandrolone exerts a significant positive effect on bone formation and that this results in a fall in the fasting plasma calcium level, and consequently calcium excretion.

Absorption↗
PubMed1987

The effect of an oral calcium load on plasma ionized calcium and parathyroid hormone concentrations in osteoporotic postmenopausal women.

Plasma ionized calcium (IC) and parathyroid hormone (PTH) concentrations were measured in 31 osteoporotic postmenopausal women at hourly intervals for 5 hours after a 1 g oral calcium load. Fifteen subjects had normal radiocalcium absorption and 16 subjects were malabsorbers of calcium. IC rose and PTH fell after the calcium load in both groups with a plateau at 3-4 hours, and the rise in IC was greater (P less than 0.01) in the normal absorbers. There was a nonsignificant trend for the fall in PTH to be greater in the normal absorbers. In the group as a whole the mean increase in IC (above baseline) at 4 hours was directly related to calcium absorption (P less than 0.025) and the mean change in PTH was inversely related to calcium absorption (P less than 0.05). These results demonstrate that in subjects with postmenopausal osteoporosis the responses of IC and PTH to an oral calcium load are a function of calcium absorptive status.

Administration, Oral↗
PubMed1987

Effects of nandrolone therapy on forearm bone mineral content in osteoporosis.

Forearm bone mineral content (BMC) was measured sequentially on and off anabolic steroid therapy in 52 postmenopausal women with osteoporosis. The steroid used was nandrolone decanoate in a dose of 50 mg every two weeks by intramuscular injection. In 16 of the patients nandrolone was given first (for 6.2 +/- 0.6 months) followed by a control period (6.1 +/- 1.0 months) and in 36 there was an initial control period (9.5 +/- 1.1 months) followed by nandrolone (for 5.8 +/- 0.4 months). Any other therapy was continued unchanged during both treatment and control periods. There was a significant rise in BMC on nandrolone (p less than 0.001) and a nonsignificant fall in BMC off nandrolone. The difference between the rates of change on and off nandrolone was highly significant (+53 vs. -7 mg/cm/year; p less than 0.001).

Aged↗
PubMed1987

Biochemical effects of a calcium supplement in osteoporotic postmenopausal women with normal absorption and malabsorption of calcium.

Although calcium supplements are widely used to reduce bone resorption in osteoporosis, their beneficial effect is not conclusively established. We have studied the acute (after 12 h) effects of an oral calcium load (1 g) in a group of 35 osteoporotic postmenopausal women, comprising 19 subjects with normal absorption and 16 subjects with malabsorption of calcium. In the subjects with normal calcium absorption the fasting urinary total hydroxyproline/creatinine ratio fell from 0.021 to 0.017 (p less than 0.001), but in those with malabsorption of calcium it did not change significantly. This difference between the two groups was significant (p less than 0.01). These results indicate that an oral calcium load rapidly suppresses bone resorption in osteoporotic subjects with normal absorption of calcium, but not in those with malabsorption of calcium.

Aged↗
PubMed1987

Treatment of postmenopausal hyperparathyroidism with norethindrone. Effects on biochemistry and forearm mineral density.

The effects of norethindrone (5 mg daily) on biochemical variables and forearm mineral density were assessed in 20 postmenopausal women with mild primary hyperparathyroidism. Norethindrone produced a significant fall in plasma calcium levels and the fasting urinary calcium-creatinine and hydroxyproline-creatinine ratios after three months of treatment. There was no change in the plasma parathyroid hormone concentrations. The forearm mineral density before treatment was low in 16 of the 20 patients and there was a significant increase in forearm mineral density after norethindrone treatment. No side effects were reported. We conclude that norethindrone is an effective treatment for mild hyperparathyroidism in postmenopausal women.

Aged↗
PubMed1986

Comparison of calcium, calcitriol, ovarian hormones and nandrolone in the treatment of osteoporosis.

Most therapy for osteoporosis has been aimed at decreasing bone resorption and is capable of preventing further bone loss. Recently, anabolic steroids have been claimed to cause increased bone mass in osteoporosis, but the mechanism for this effect is not understood. In this study calcium, and calcium with calcitriol, caused a slowing of forearm bone mineral loss. Calcium and ovarian hormones, with or without calcitriol, caused a small non-significant rise in forearm mineral density, and nandrolone decanoate 50 mg intramuscularly, every 2 or 3 weeks caused a significant rise in forearm mineral density (+15.9 +/- 2.4 mg/ml/yr and +13.7 +/- 3.4 mg/ml/yr, respectively). The 3-weekly regime caused few side effects and is considered the optimal dose. The striking rise in bone density in patients in whom bone resorption was controlled before therapy, suggests that anabolic steroids can increase the bone formation rate.

Aged↗
PubMed1986

Calcium metabolism and osteoporosis in corticosteroid-treated postmenopausal women.

Osteoporosis is a common complication of corticosteroid therapy and it is associated with both decreased bone formation and increased bone resorption. We have measured radiocalcium absorption and the fasting urinary calcium/creatinine and hydroxyproline/creatinine ratios in 30 postmenopausal women receiving prednisolone therapy and compared the patients with normal spine radiographs (N = 14) with those whose spine radiographs showed osteoporosis (N = 16). The osteoporotic cases had lower radiocalcium absorption (p less than 0.001), higher fasting urinary calcium (p less than 0.05), and higher fasting urinary hydroxyproline excretion (p less than 0.001). As calcium absorption has a positive effect on calcium balance and urinary calcium a negative effect, the difference between these two variables was calculated in each case. This derived variable (radiocalcium absorption--fasting urinary calcium/creatinine) disclosed a greater difference between the osteoporotic and normal groups (p less than 0.0001) than either variable alone.

Aged↗
PubMed1985

The tubular maximum for calcium reabsorption: normal range and correction for sodium excretion.

Increased tubular reabsorption of calcium is one of the three variables which can contribute to the pathogenesis of hypercalcaemia. It is therefore important to establish the normal range for this variable in a manner which allows for its variation with the plasma calcium concentration. Graphic methods depicting the relationship between urinary calcium excretion and plasma calcium concentration are valid but cumbersome and imprecise. The notional tubular maximum for calcium reabsorption (TmCa) has therefore been calculated in 130 healthy young subjects and a normal range of 1.75-2.61 mmol/l of glomerular filtrate established. Owing to the dependence of urinary calcium on urinary sodium, TmCa was negatively related to sodium excretion. Because the latter was higher in the males than the females, mean TmCa was slightly (but not significantly) lower in our male than our female subjects. The normal range of TmCa, corrected to zero sodium excretion, is 1.98-2.76 mmol/l of glomerular filtrate. The TmCa was also calculated using plasma calcium values corrected for albumin concentration. The range of TmCa using both corrections is 1.98-2.71 mmol/l of glomerular filtrate.

Absorption↗