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  • 1
    ISSN: 1432-0495
    Keywords: Key words Nutrient dynamics ; Sedimentation ; Resuspension ; Scandinavia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The yearly nutrient supply from land and atmosphere to the study area in SW Kattegat is 10 900 tons of N and 365 tons of P. This is only few percent of the supply from adjacent marine areas, as the yearly transport through the study area is 218 000 tons of N and 18 250 tons of P. Yearly net deposition makes up 1340 tons of N (on average 2.5 g m–2 yr–1) and 477 ton of P (on average 0.9 g m–2 yr–1). Shallow-water parts of the study area have no net deposition because of frequent (〉35% of the year) resuspension. Resuspension frequency in deep water is 〈1% of the year. Resuspension rates, as averages for the study area, are 10–17 times higher than net deposition rates. Because of resuspension, shallow-water sediments are coarse lag deposits with small amounts of organic matter (1.1%) and nutrients (0.04% N and 0.02% P). Deep-water sediments, in contrast, are fine grained with high levels of organic matter (11.7%) and nutrients (0.43% N and 0.15% P). Laboratory studies showed that resuspension changes the diffusive sediment water fluxes of nutrients, oxygen consumption, and penetration into the sediment. Fluxes of dissolved reactive phosphate from sediment to water after resuspension were negative in organic-rich sediments (13.2% organic matter) with low porosity (56) and close to zero in coarse sediments with a low organic matter content (2.3%) and high porosity (73). Fluxes of inorganic N after resuspension were reduced to 70% and 0–20% in relation to the rates before resuspension, respectively.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 35 (1983), S. 708-711 
    ISSN: 1432-0827
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 36 (1984), S. 269-273 
    ISSN: 1432-0827
    Keywords: Bone loss (osteopenia) ; Calcium ; Corticosteroids (glucocorticosteroids) ; Fluoride ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary To evaluate the effect of prednisone and triple treatment (sodium fluoride, calcium, and vitamin D) on trabecular and cortical bone serial bone mineral content (BMC) measurements were made at a metaphyseal (BMCD) and diaphyseal (BMCP) site on the forearm on 31 consecutive and previously bone-healthy patients scheduled for at least 24 weeks high-dose prednisone treatment. The patients were randomized into two further treatment groups: group I (n=16) received prednisone plus triple treatment and group II (n=15) received only prednisone. The two groups were similar with regard to age, sex, prednisone dose, and initial BMC. During 24 weeks treatment, BMCD (partially representing trabecular bone) and BMCP (mainly representing cortical bone) fell significantly and similarly, demonstrating that there is no preventive effect on bone mineral loss on the triple regimen. The BMC fall after 12 weeks was significantly more pronounced for metaphyseal (partially trabecular) than for diaphyseal (cortical) bone, whereas the values did not differ significantly after 24 weeks; this indicates a greater sensitivity to the hormone treatment of trabecular bone. In the entire group, the fall in BMC correlated positively with individual prednisone dose, significant at the diaphyseal site (r=0.39,P〈0.05), but not at the metaphyseal site (r=0.31, P=0.08). It is concluded that corticosteroid-induced osteopenia is a diffuse bone disease which affects trabecular as well as cortical bone, suggesting that BMC measured on the forearm reflects changes in bone mineral at other locations.
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  • 4
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Menopause ; Estrogen ; Pyridinoline ; Bone resorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Objective: To evaluate and compare the effects or oral and transdermal estrogen replacement therapy on biochemical markers of bone resorption in early postmenopausal women Design: Controlled, randomized group comparison. Setting: Outpatient clinic for menopausal women and research into osteoporosis. Subjects: Sixty healthy women menopausal for less than 5 years and who had never received any medications interfering with bone metabolism. Interventions: The 60 women were randomly allocated to 3 months therapy with either oral conjugated estrogens (0.625 mg/day) (n = 28) or transdermal estradiol (50 jig/day) (n = 32) in cyclical combination with medroxyprogesterone acetate (5 mg/day). Main outcome measures: Traditional (urinary calcium/creatinine and hydroxyproline/creatinine) and the new specific (urinary pyridinoline/creatinine and deoxypyridinoline/creatinine) markers of bone resorption were determined before and after 3 months of treatment. Results: In both groups, circulating levels of estrone and estradiol were significantly (P 〈 0.001) increased during treatment. In women treated with oral conjugated equine estrogens, urinary calcium/creatinine and hydroxyproline/creatinine ratios were significantly (P 〈 0.05) reduced. Pyridinoline/creatinine ratio fell from 69.1 (4) [mean (SEM)] to 50 (4) μmol/μmol (P 〈 0.01) and deoxypyridinoline/creatinine ratio fell from 10.8 (1) [mean (SEM)] to 8.3 (0.8) μmol/μmol (P 〈 0.01). In the group treated with transdermal estradiol, urinary hydroxyproline/creatinine ratio was significantly (P 〈 0.05) reduced. Pyridinoline/creatinine ratio fell from 66.3 (4) [mean (SEM)] to 46.2 (3) μmol/μmol (P 〈 0.01) and deoxypyridinoline/creatinine ratio fell from 11.5 (1.5) [mean (SEM)] to 7.7 (0.6) μmol/μmol (P 〈 0.01). There were no differences between the evolution of the biochemical variables in the two groups. Conclusion: These results suggest that oral conjugated equine estrogens and transdermal estradiol, in the given doses, are equally effective in reducing postmenopausal bone resorption.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 54 (1994), S. 381-384 
    ISSN: 1432-0827
    Keywords: Pyridinoline ; Free pyridinoline ; Deoxypyridinoline ; Urinary excretion ; Pre- and postmenopausal ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The urinary excretion of pyridinolines either in the free form or linked to different peptide fragments of type I collagen are intensively studied as new biochemical markers of bone resorption. In the present study we compared the urinary excretion of free pyridinoline (F-Pyr) determined by enzyme-linked immunosorbent assay (ELISA) (Collagen CrosslinksTM Kit, Metra Biosystems) to pyridinoline (Pyr), and deoxypyridinoline (D-Pyr) determined by high performance liquid chromatography (HPLC) in early postmenopausal women treated with either hormone replacement therapy or placebo and in healthy age-matched premenopausal women. Other markers of bone metabolism were included for comparison. Compared with the premenopausal women, the postmenopausal women had significantly increased values of the biochemical parameters. F-Pyr, Pyr, D-Pyr, and T-Pyr (=Pyr+D-Pyr) decreased during hormone therapy. D-Pyr correlated with the rate of bone loss, whereas this was not the case for F-Pyr. The correlations between the markers yielded r values of 0.71 (F-Pyr vs Pyr), 0.67 (F-Pyr vs D-Pyr), and 0.71 (F-Pyr vs T-Pyr). In conclusion, the present study shows that the newly introduced ELISA for determination of the free pyridinolines is less sensitive than pyridinium crosslinks measured by high performance liquid chromatography (HPLC) in hydrolyzed urine for the changes in calcium metabolism that occur at menopause and during hormone replacement therapy. Whether this limitation will be balanced out by avoiding the inconvenience of the complicated, expensive, and timeconsuming HPLC procedure is still being debated.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 57 (1995), S. 1-5 
    ISSN: 1432-0827
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0827
    Keywords: Key words: Osteoporotic fractures — Ipriflavone — Fracture intervention trial.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. In order to investigate the efficacy of ipriflavone (IP) on the prevention of vertebral fractures and the effect on bone mineral density (BMD) in women with postmenopausal osteoporosis, a large multicentric European study was designed and is presently ongoing. Included in the study were 460 Caucasian, nonobese postmenopausal women aged 〉45 and 〈75 years, menopaused for at least 12 months. Inclusion was on the basis of a lumbar bone mineral density (BMD) lower than 2 SD compared with healthy women aged 50 years, corresponding to values below 0.860 g/cm2 (antero-posterior measurement) by Hologic QDR 1000. Women with prevalent vertebral fractures were excluded as well as those presenting secondary osteoporosis or having been treated with medications that could affect bone metabolism. This study was designed as a 3-year, double-blind, placebo-controlled, parallel group study that randomized the women to the oral administration of either 3 × 200 mg/day of IP or placebo. All patients received a daily supplement of 500 mg calcium. The primary purpose of the study was to evaluate the efficacy of IP in preventing vertebral nontraumatic fractures. Fracture is defined here as a ≥20% decrease in any anterior, central, or posterior T4–L4 vertebral height. Blinded vertebral X-ray readings and vertebral morphometry have been centralized in an independent Center, with standardized evaluation of two experts. Power calculations have been based on the hypothesis that 21% of placebo-treated patients would fracture within 3 years and that treatment with IP would lead to a 50% reduction in the incidence of fracture. Statistical tests have been designed to have a power of 80%, with a type I error equal to 5%. Secondary endpoints were changes in vertebral, radial, and femoral BMD. Centralized controls on 100% BMD scans would ensure the good quality of BMD readings. This study should verify the hypothesis that IP significantly decreases the risk of vertebral fracture in postmenopausal, osteoporotic women.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0827
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Carboxy-terminal pyridinoline cross-linked telopeptide of type I collagen (ICTP) in serum has recently been proposed as a new biochemical marker of bone resorption. In the present study we compared serum ICTP with radiopharmaceutical and histomorphometric measurements of bone turnover in postmenopausal women with mild osteoporosis, and assessed the effect of hormone replacement therapy (HRT) (2 mg 17β-estradiol plus 1 mg norethisterone daily) and anabolic steroid therapy (50 mg nandrolone decanoate (ND) i.m. every 3 weeks) on serum ICTP in two double-blind placebo-controlled studies with 55 to 75-year-old women. Serum ICTP measured by radioimmunoassay (RIA) correlated significantly with the 24-hour whole body retention of 99m-technetium diphosphonate (Rho=0.47, P〈0.001, n=66), but not with histomorphometric measurements of bone turnover in iliac crest biopsies. One year of HRT (n=16) versus placebo (n=15) did not produce significant changes in serum ICTP. Compared with placebo (n=17), 1 year of ND (n=19) produced an increase in serum ICTP of 90±16% (P〈0.0001); 6 months after discontinuation of the treatment, serum ICTP had returned to pretreatment values. We conclude that serum ICTP does reflect bone metabolism in postmenopausal osteoporosis, but it is not a sensitive marker of the changes in bone resorption induced by hormone replacement therapy, and it does not correspond with other measures of bone resorption during anabolic steroid therapy.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0827
    Keywords: Calcitonin ; Follow-up ; Osteoporosis ; Biochemical markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract We reviewed data on 42 postmenopausal women with established osteoporosis (forearm fracture or a low bone mass0 who had been randomly treated for 1 year with either rectal salmon calcitonin (sCT), 100 IU daily (n=25) or nasal sCT, 200 IU daily (n=17) applying an estimation algorithm for bone loss rates. Both groups received a daily calcium supplement of 500 mg. A group of 18 age-matched women who received no treatment served as controls. The bone mineral content of the distal forearm (BMCarm) was measured every 3 months by single photon absorptiometry. The individual rates of change during the 1-year period were calculated by linear regression analysis (αBMCarm). Bone loss rates were estimated initially and after 1 year of therapy by measurements of serum alkaline phosphatase, plasma bone Gla protein, and fasting urinary hydroxyproline and calcium (both corrected for creatinine excretion) according to the estimation algorithm. Both administration forms revealed significant control group-corrected decreases in serum and urine markers of bone turnover of 15–40% (P〈0.05–0.01) and positive outcomes of 2% in αBMCarm (P〈0.01). The estimated effect on bone mass was expressed as the difference between the bone loss estimated after 1 year and initially (ΔESTBIO). A significant correlation was seen between αBMCarm and ΔESTBIO (r=0.5, P〈0.0001). We conclude that the effect of sCT on bone can be followed up by biochemical markers for bone turnover, i.e., by an annual blood and fasting urine sample, applying an estimation algorithm for the rate of bone loss.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 22 (1976), S. 341-343 
    ISSN: 1432-0827
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Type of Medium: Electronic Resource
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