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Biomedical subjects

C Christiansen

Publications and source records attributed to C Christiansen.

At least 343 records · Page 19Linked to original sources
PubMed1989

Estimation of total body composition from single photon absorptiometry measurement of forearm fat content.

The forearm fat content (FATarm, measured by single photon (125I) absorptiometry) and the 24-h urinary creatinine excretion (24 Ucrea) were determined in 29 healthy adults (12 males and 17 females), whose total body fat percentage was measured by three different methods: (i) Dual photon (153Gd) absorptiometry (DPA); (ii) body density measurements (BD); and (iii) total body potassium determinations (TBP). Lean body mass (by DPA, BD, and TBP) correlated significantly with 24 Ucrea (r = 0.87-0.89, standard error of estimate (SEE) = 5.2-6.3 kg). The total body fat percentage could be predicted from FATarm with SEEs at 3.4-5.8 (r = 0.85-0.88) and from 24 Ucrea + body weight with SEEs at 5.1-7.5 (r = 0.61-0.72). We conclude that the FATarm measurement represents a new tool for simple assessment of body composition on a group basis.

Adipose Tissue↗
PubMed1988

Measurement of spinal or peripheral bone mass to estimate early postmenopausal bone loss?

This report presents data from 153 healthy, early postmenopausal women who were randomly allocated to two years of treatment with estrogen or placebo. Bone mineral content in the forearms was measured by single-photon absorptiometry, and bone mineral density of the lumbar spine and total-body bone mineral by dual-photon absorptiometry, before and after one and two years of treatment. At the end of the two years, there were highly significant differences of 6 to 7 percent between the estrogen and the placebo groups at all sites measured. The range of the changes of the spine measurement was twice that of the forearm and total-body measurements. It is concluded that measurement of the forearm by single-photon absorptiometry is superior to measurement of the spine by dual-photon absorptiometry both in clinical studies and in the individual patient for detecting estrogen-dependent bone loss and its treatment by estrogen replacement.

Double-Blind Method↗
PubMed1988

Iliac crest biopsy in longitudinal therapeutic trials of osteoporosis.

Changes in tetracycline-labelled iliac crest biopsies taken before and after 1 year of treatment with nandrolone decanoate + calcium, 17 beta-estradiol + norethisterone acetate + calcium or placebo were compared with changes in plasma bone Gla protein (pBGP), serum alkaline phosphatase (sAP), whole body retention (WBR) of Technetium-99m-diphosphonate [( 99mTc]DP) and bone mineral content (BMC) of the forearm. Based on a comparison between biopsy and noninvasive results, as well as on evaluation of the variation in the groups, certain guidelines for the use of bone histomorphometry in longitudinal therapeutic trials are suggested. It is proposed that bone biopsy is not used to monitor changes in amount of bone and that evaluation of changes in biopsy evaluated bone turnover is only attempted when the groups are large.

Aged↗
PubMed1988

Blood pressure during oestrogen/progestogen substitution therapy in healthy post-menopausal women.

In order to explore the long-term effect of hormone (17 beta-oestradiol) substitution therapy on blood pressure in healthy post-menopausal women, we reviewed the data from five long-term (1-2 yr), double-blind, placebo-controlled studies carried out in our department over the last decade. Three of the studies related to early post-menopausal women (mean age 50 in all three cases) and two involved later post-menopausal women (mean ages 64 and 70, respectively). The systolic blood pressure values during hormonal substitution therapy showed no change in relation to those recorded during placebo administration, whereas the diastolic blood pressure fell slightly in all five studies. However, in that based on the oldest subjects, the results were not statistically significant. It was therefore concluded that hormone substitution therapy with 17 beta-oestradiol has no adverse effect on blood pressure, and may even have a beneficial action.

Adult↗
PubMed1988

Continuous oestrogen-progestogen treatment and bone metabolism in post-menopausal women.

The suggestion that norethisterone acetate (NETA) stimulates bone formation prompted us to investigate calcium and bone metabolism in post-menopausal women treated with a continuous combination of oestrogen and NETA. The study included 49 healthy post-menopausal women. After an initial examination the women were randomly allocated to 2 yr of treatment with either hormones or placebo; 43 women completed the study. Within the first year of treatment the hormone group showed a slight, but significant, increase in bone mineral content in the forearms (single photon absorptiometry) and in the total skeleton (dual photon absorptiometry). After this initial increase the bone mass remained constant throughout the trial. Bone mineral density of the spine (dual photon absorptiometry) showed a significant increase of more than 5% in the hormone group. There were significant decreases of 4-7% in bone mass in the placebo group over 2 yr. Biochemical estimates of bone turnover (plasma bone Gla protein, serum alkaline phosphatase, fasting urinary calcium and fasting urinary hydroxyproline) fell significantly in the hormone group, but remained unchanged in the placebo group. We conclude that continuous administration of NETA in combination with oestrogen provides effective prophylaxis against post-menopausal bone loss, although it does not produce a persistent positive calcium balance in early post-menopausal women.

Alkaline Phosphatase↗
PubMed1988

Lack of seasonal variation in bone mass and biochemical estimates of bone turnover.

Three previous studies have indicated a seasonal variation in bone mineral content, with values during the summer being 1.7% to 7.5% higher than during the winter. We have examined the seasonal influence on both bone mass, biochemical estimates of bone turnover and vitamin D metabolites in 86 healthy women, aged 29-53 years. All participants were followed up for 2 years with examinations every 6 weeks or 3 months. Bone mineral content in the proximal and distal part of the forearm (single photon absorptiometry) did not reveal any significant seasonal variation, whereas bone mineral density of the lumbar spine (dual photon absorptiometry) indicated that the highest values occurred in winter. None of the biochemical parameters showed any statistically significant cyclical changes. Serum concentrations of 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D3 showed a highly significant seasonal variation, whereas the serum 1,25-dihydroxyvitamin D concentration was virtually unchanged. We conclude that seasonal variation in bone mineral content and bone turnover should not be taken into account when interpreting data from longitudinal studies of healthy pre- and postmenopausal women on a sufficient vitamin D nutriture.

Adult↗
PubMed1988

Effects of smoking on serum lipoproteins and bone mineral content during postmenopausal hormone replacement therapy.

We examined the effect of smoking on the treatment response in serum estrogens, serum lipids and lipoproteins, and bone mineral content in 110 postmenopausal women treated for 2 years with either percutaneous or orally administered combined hormones or placebo and followed up by examinations every 3 months. Serum estradiol and estrone levels during oral hormone administration were lower in smokers than in nonsmokers, whereas no differences related to smoking habits were observed during percutaneous hormone administration. Serum total and low-density lipoprotein cholesterol were significantly reduced in both smokers and nonsmokers receiving hormones, but the response in smokers was only half that observed in nonsmokers (not significant). When the impact of the route of hormone administration was examined in relation to smoking habits, the response in serum total and low-density lipoprotein cholesterol in smokers receiving oral hormones was significantly lower (p less than 0.05) than that observed in nonsmokers. No differences in serum lipids or lipoproteins were observed between smokers and nonsmokers receiving percutaneous hormones. The response in bone mineral content in smokers and nonsmokers receiving percutaneous hormones and placebo was not significantly different, although the overall response differed significantly in the two groups (p less than 0.001). In contrast, the response in smokers receiving oral hormones was significantly lower than that observed in the corresponding nonsmokers (p less than 0.01). We conclude that smoking greatly affects the response on circulating levels of estrogens in postmenopausal women treated with orally administered hormone replacement therapy and that the subsequent treatment response on serum lipids and lipoproteins and on bone mineral content is reduced accordingly. The study suggests that alternative routes of administration should be considered when postmenopausal estrogen therapy is instituted in women who smoke.

Administration, Cutaneous↗
PubMed1988

Rates of bone loss in normal women: evidence of accelerated trabecular bone loss after the menopause.

We have followed the changes in bone mass over 2 years in 42 premenopausal, seven perimenopausal and 76 postmenopausal women. The latter had passed a natural menopause between 6 months and 7 years previously. Bone mass was measured every 3 months at the proximal and distal forearm sites by single photon absorptiometry, and every 6 and 12 months in the lumbar spine and whole body by dual photon absorptiometry. The relative content of trabecular bone is approximately 15, 50, 60 and 20% at these four sites. Before the menopause there was a significantly low rate of bone loss from the two forearm sites and the whole body, whereas the spinal loss was insignificant. The rate of loss was five- to ten-fold higher at all sites after the menopause (P less than 0.001). With increasing menopausal duration the rate of loss declined at the two forearm sites and whole body (P less than 0.01). The distal forearm loss was larger than the proximal, both before and after the menopause (P less than 0.01). From the forearm results we thus conclude that a slightly larger loss of trabecular than cortical bone takes place both before and immediately after the menopause. The loss of both types of bone is, however, much larger after the menopause and this rapid bone loss seems to take place throughout the skeleton.

Adult↗
PubMed1988

Plasma BGP: an indicator of spontaneous bone loss and of the effect of oestrogen treatment in postmenopausal women.

One hundred and ninety-one healthy early postmenopausal women, aged 45-54 years, were randomized to 2 years of treatment with (a) percutaneous 17 beta-oestradiol combined with progesterone (n = 29) or placebo (n = 28); (b) oral oestradiol valerate combined with cyproterone acetate (n = 37) or placebo (n = 39); (c) 24R, 25 (OH)2D3 (n = 29) or placebo (n = 29). We measured the plasma bone Gla-protein (BGP), bone mineral content of the proximal forearms (BMC), bone mineral density in the spine (BMDspine) and total body bone mineral (TBBM) in all the women before, and during, the study. In the groups of women receiving the oestrogen preparations, the plasma BGP decreased highly significantly (P less than 0.001) to a premenopausal level. The initial plasma BGP concentration was significantly related to the loss of BMC (P less than 0.001) in the placebo groups. The changes in plasma BGP were an indicator of the oestrogen response on BMC. We conclude that serial determinations of plasma BGP are useful for determination of the effect of oestrogen therapy in groups of patients, and that plasma BGP measured at the time of the menopause indicates what the rate of bone loss will be.

Calcium-Binding Proteins↗
PubMed1988

Serum bone Gla-protein as a marker of bone growth in children and adolescents: correlation with age, height, serum insulin-like growth factor I, and serum testosterone.

Serum bone Gla-protein (BGP) was determined by RIA in 450 normal children (229 girls and 221 boys, aged 6-19 yr). Serum BGP concentrations changed in relation to age and sex with a pattern that resembles the height velocity curves for children. The increase in serum BGP occurred at the expected age of the growth spurt in both sexes, and the peak values occurred at the age of 12 yr in girls [mean, 49.2 +/- 5.6 (+/- SE) micrograms/L] and 14 yr in boys (64.0 +/- 6.3 micrograms/L). In the boys aged 10-14 yr and in the girls aged 9-12 yr, serum BGP correlated significantly with serum insulin-like growth factor I (IGF-I), serum testosterone, age and height. When the interrelationship was analyzed by means of partial correlation, with age held constant, serum BGP still correlated significantly with the other parameters, but when height was fixed there was only a correlation with serum IGF-I. In children with untreated central precocious puberty, the mean serum BGP concentration was significantly higher than in age-matched normal children [mean, 61.4 +/- 31.7 (+/- SD) vs. 29.0 +/- 10.3 micrograms/L; P less than 0.001]. Serum BGP values decreased significantly in these patients during 1 yr of treatment with a LHRH analog (buserelin) and cyproterone acetate. We conclude that serum BGP is a sensitive marker of bone growth in normal children and in children with increased growth velocity. Repeated measurements may provide useful information in the diagnosis and treatment of children with disturbances in bone turnover.

Adolescent↗
PubMed1988

The effect of a gonadotropin-releasing hormone agonist analog (nafarelin) on bone metabolism.

The effect on bone metabolism of an agonist analog of GnRH, nafarelin, was studied in 16 premenopausal women, who received 200 micrograms nafarelin/day for 6 months, and 9 premenopausal women, who received 400 micrograms nafarelin/day for 6 months, followed by a 6-month follow-up period. Bone mineral content in the forearm (measured by single photon absorptiometry) and in the spine (measured by dual photon absorptiometry) significantly decreased after 6 months of treatment with 400 micrograms nafarelin, but 6 months after termination of treatment all bone mineral measurements had returned to pretreatment levels. The bone mineral measurements in the 200 micrograms group did not change throughout the study. In both treatment groups the biochemical estimates of bone turnover increased significantly to postmenopausal levels. Withdrawal of treatment resulted in an abrupt decrease in the bone resorption parameters (fasting urinary hydroxyproline to creatinine and calcium to creatinine excretion ratios and serum phosphate), whereas there was a protracted fall in the bone formation parameters (plasma bone Gla protein and serum alkaline phosphatase) 6 months after termination of treatment. Our findings demonstrate that nafarelin in both doses increased biochemical indices of bone turnover, that 400 micrograms/day nafarelin resulted in a significant decrease in bone mineral content, and that these effects were reversible.

Adult↗
PubMed1988

Comparisons between two receptor assays for 1,25-dihydroxyvitamin D.

We present a competitive protein binding assay (CPBA) for 1,25(OH)2D employing 1,25(OH)2D receptor from calf thymus, which was compared with a CPBA-employing receptor from rachitic chick intestine. The thymus receptor assay was more sensitive, specific and precise than the intestinal receptor assay. The thymus receptor assay measured both 1,25(OH)2D2 and 1,25(OH)2D3 with equal affinity, whereas 1,25(OH)2D2 was 1.1 times less potent than 1,25(OH)2D3 in the displacement from the chick intestinal receptor. Mean serum values of 1,25(OH)2D in normal subjects, post-menopausal women, pregnant women, and patients with chronic renal failure measured by the two assay systems did not differ. Furthermore, both assays showed that 1,25(OH)2D was unchanged in post-menopausal women after treatment with vitamin D2 or vitamin D3, 4000 IU/day for 8 weeks. We conclude that the high sensitivity of the thymus receptor and the equal affinity for the D2 and D3 analogue make the thymus receptor assay a reliable alternative to the chick intestinal receptor assay.

Adult↗
PubMed1988

Intranasal calcitonin for prevention and treatment of osteoporosis.

Age-related diseases constitute an ever increasing problem in an ageing population. The objectives of future medical research in this field should not only seek to increase longevity, but also to improve the quality of life of the elderly and to enable them to live independently for a longer period of time. Osteoporosis is a prime example of such a disease, because we have the tool to prevent it, i.e. oestrogen and calcitonin, and because in all probability it will some day be curable.

Administration, Intranasal↗
PubMed1988

Age-related bone loss in women evaluated by the single and dual photon technique.

Bone mass and density were measured at two forearm sites (proximal and distal BMC/BMD) and in the spine (spinal BMC/BMD) by respectively single and dual photon absorptiometry in 141 healthy women aged 20-80 years. The proximal forearm site contains approximately 15% trabecular bone and the distal site equal amounts of trabecular and cortical bone. At all three sites linear regression analysis on pre- and postmenopausal women separately revealed accelerated decline in bone density after the menopause. Polynomial regressions in BMC and BMD versus menopause-adjusted age fitted the changes better than a linear regression in the peripheral skeleton, but not in the spine. In both the forearms and the spine the age-related reduction in bone could be described by a combined model, assuming a linear decrease before the menopause and an exponential one thereafter. According to this model, the premenopausal annual changes were 0.067% (proximal site), 0.187% (distal site) and 0.098% (spine). The annual changes during the first postmenopausal year were 3.7, 3.7 and 4.6%. No matter which model was applied to the data, the reduction in the oldest women was lowest in the spine. These data indicate that there are some small differences in the age-related changes in cortical and trabecular bone, but that the reduction of both types of bone accelerates after the menopause.

Adult↗
PubMed1988

Long-term precision of dual photon absorptiometry in the lumbar spine in clinical settings.

We have investigated the long-term in vivo precision of a dual photon spine scanner using three different Gd sources and compared it with that of the single photon scanner. Standard values were significantly different with the three Gd sources. With the second there was also a systematic increase of 2% per 60,000 cps in the 44 KeV channel as the source decayed, whereas no such shift was found with the other two sources. This resulted in a significant in vivo intrasource (P less than 0.05) and intersource (P less than 0.01) variation and a six-month reproducibility ranging from 3.7 to 8.1%. After correction for these systematic errors the clinically important 2-year reproducibility in 26 premenopausal women was 3.4 +/- 1.3% for spinal BMC and 3.7 +/- 1.7% for spinal BMD. In comparison, the forearm single photon scanner had a long-term precision of 1.0 +/- 0.3%. With the presented techniques spinal measurements may therefore require 11.6 times (3.4(2):1.0(2] as many participants as the forearm measurements to detect the same changes in bone mass.

Adult↗
PubMed1988

Accuracy of lumbar spine bone mineral content by dual photon absorptiometry.

The accuracy of measurement of the bone mineral content (BMC, g) and bone mineral density (BMD, g/cm2) of the lumbar spine by dual photon absorptiometry (DPA) was estimated by means of two different spine scanners (a Nuclear Data 2100 and a Lunar Radiation DP3). The lumbar spines of 13 cadavers were used. BMC and BMD were measured in situ and on the excised vertebrae in a solution of water/ethanol; and covered with ox muscle/porcine muscle/lard. The actual mineral weight and areal density were determined after chemical maceration, fat extraction, drying to a constant weight, ashing for 24 hr at 600 degrees C, and correction for the transverse processes. The true are was measured by parallax free X rays and planimetry. All measurements of BMC or BMD were highly interrelated (r = 0.94-0.99). The standard error of estimate (s.e.e.) of BMC in situ versus BMC in water/ethanol was 5.2%. The agreement between the BMD values of the two scanners was very good (s.e.e. = 2.9%). BMC in situ predicted the actual vertebral mineral mass with an s.e.e. of 8.1%. BMD in situ and BMD in water/ethanol predicted the actual area density with s.e.e.s of 10.3% and 5.0%, respectively. This study discloses the correlation and accuracy error of spinal DPA measurements in situ in whole cadavers versus the actual BMC and BMD. The error, which is underestimated in in vitro studies, amounts to 10%.

Adult↗
PubMed1987

Prediction of rapid bone loss in postmenopausal women.

Bone loss was determined in 178 women in the early postmenopausal period by photon absorptiometry measurement of forearm bone mineral content (BMC) every 3 months for 2 years. With a sequential cut-off technique, the results of a single determination of body fat mass, urinary calcium and hydroxyproline, and serum alkaline phosphatase, carried out at the first examination, correctly identified 79% of "fast bone losers" (bone loss greater than 3% annually) and 78% of "slow bone losers". With this simple approach the majority of women at highest risk of osteoporotic fractures in later life can be identified in the early postmenopausal period and started on prophylactic hormone replacement therapy.

Female↗