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  • 1
    Electronic Resource
    Electronic Resource
    Energetic costs and efficiencies of ciliary filter feeding (1987)
    Springer
    Marine biology 94 (1987), S. 445-449 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between activity of the lateral cilia and oxygen consumption was studied in fragments of the gills of Mytilus edulis L., and the effects of stimulation with the nerve transmitters serotonin and dopamine were measured. Beat frequency, f, and oxygen consumption, MO 2, increased with increasing doses of the transmitters. Serotonin increased f up to 26 Hz and the relationship with MO 2 could be described by MO 2 (μl cm-2 gill area h-1)=0.44+0.35 f (r=0.99). The relationship after dopamine stimulation did not differ from that established by serotonin, but the maximum value of f was only 19 Hz. At the frequency of 10 Hz, characteristic of undisturbed pumping, the cells carrying the lateral cilia were estimated to account for one third of the total oxygen consumed, equivalent to 1.05×10-10 mol ATP cm-2 s-1. This rate of synthesis of ATP was compared with the rate at which the active cilia hydrolyse ATP. ATP hydrolysis ranged from 58 to 87% of synthesis as the assumed ratio between number of ATP molecules hydrolysed per beat and number of dynein molecules ranged from 2 to 3. The rate at which ATP is hydrolysed by the active cilia was compared with the work done in pumping water. At two estimates available of the pumping pressure, 1.4 and 2.5 mm H2O, the work amounted to 1.4×10-6 or 2.5×10-6 joule cm-2 s-1, equivalent to 2.9×10-11 and 5.2×10-11 mol ATP cm-2 s-1. The efficiencies of work thus corresponded to 48 or 86% at the ATP/dynein ratio of 2. The overall efficiencies of the mussel pump amounted to 18 or 32%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428251
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  • 2
    Electronic Resource
    Electronic Resource
    Human growth hormone and growth hormone releasing hormone: A double-masked, placebo-controlled study of their effects on bone metabolism in elderly women (1993)
    Springer
    Osteoporosis international 3 (1993), S. 330-336 
    Details
    ISSN: 1433-2965
    Keywords: Growth hormone ; Growth hormone releasing hormone ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We treated 42 postmenopausal women with decreased bone mass for 12 weeks with human growth hormone, growth hormone releasing hormone, or placebo. Bone density and biochemical markers were determined before and during treatment, and 4 weeks after withdrawal. Biochemical markers of bone formation and resorption increased significantly in the group treated with growth hormone, whereas no changes were seen in the other groups. After withdrawal of therapy the bone markers declined without reaching baseline values. Bone density in the forearm, spine and proximal femur was unchanged in all groups. We conclude that treatment with growth hormone stimulates bone metabolism in elderly postmenopausal women with decreased bone mass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01637319
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    A 2-Year Phase II Study with 1-Year of Follow-up of Risedronate (NE-58095) in Postmenopausal Osteoporosis (1997)
    Springer
    Osteoporosis international 7 (1997), S. 488-495 
    Details
    ISSN: 1433-2965
    Keywords: Keywords: Bisphosphonates; Postmenopausal osteoporosis; Risedronate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: This paper presents the results of a two-center, double-masked, placebo-controlled, randomized, oral-dose study of risedronate treatment in postmenopausal osteoporosis. Patients had at least one, but no more than four prevalent vertebral fractures at baseline. They received either 2.5 mg continuous risedronate, 2.5 mg cyclic risedronate, or placebo for 2 years. Both risedronate and placebo were formulated as hard gelatin capsules. All women furthermore received a daily calcium supplement of 1 g which was taken separately from the study drug. During the 1-year of follow-up, all women received only a daily calcium supplement of 1 g. A total of 132 patients were enrolled (44 in each treatment group), of which 73% completed the 2-year treatment period and 70% all 3 years. Generally the outcome of the study was negative. Lumbar spine bone mineral density (BMD) increased 1.2% (NS) and 0.8% (NS) and after 2 and 3 years in the group treated with continuous risedronate, 1.7% (NS) and 2.3% (p 〈 0.05) in the group treated with cyclic risedronate, and 0.6% (NS) and 1.7% (NS) in the placebo group. BMD in the femoral neck increased 2.9% (p 〈 0.05) and 0.9% (NS) after 2 and 3 years in the group treated with continuous risedronate, 1.3% (NS) and 2.4% (p 〈 0.01) in the group treated with cyclic risedronate, and 1.3% (NS) and 2.6% (p 〈 0.01) in the placebo group. The differences between all three groups in spinal and femoral BMD after 2 years were not statistically significant, bur reached statistical significance after 3 years (p 〈 0.01) in the femoral neck. Only minor changes were observed in the measured markers of bone turnover. Both the incidence and rate of new vertebral fractures showed no overall differences between the groups. The distribution of adverse events was similar across treatment groups. None of the serious adverse events were considered causally related to risedronate. The lack of effect shown in the present study may be explained by insufficient dose regimen and/or impaired absorption from the intestinal tract. Further investigations (ongoing phase III trials) are needed to define future dose regimens in order to validate the effect on bone mass, fracture rate and biochemical markers. In these studies another formulation of the drug and other dosing instructions are used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00004152
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  • 4
    Electronic Resource
    Electronic Resource
    High Bone Turnover is Associated with Low Bone Mass and Spinal Fracture in Postmenopausal Women (1997)
    Springer
    Calcified tissue international 60 (1997), S. 255 -260 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Tiludronate — Postmenopausal osteoporosis — Urinary CrossLaps — Osteocalcin — Bone mineral density —Spinal fracture — Osteoporosis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. A group of 366 healthy, white postmenopausal women, aged 50–81 years, mean age 66 years, were selected from the screened population of Scandinavians who were part of a multicenter study of the efficacy of tiludronate, a new bisphosphonate, in established postmenopausal osteoporosis. Eighty-eight women had a lumbar spine bone mineral density (BMD) above 0.860 g/cm2, and 278 women had a BMD below 0.860 g/cm2. Spinal fracture was diagnosed from lateral spine X-ray studies and defined as at least 20% height reduction (wedge, compression, or endplate fracture) in at least one vertebra (T4–L4). Bone resorption was assessed by measurement of the urinary excretion of type I collagen degradation products by the CrossLaps™ enzyme-linked immunoassay (ELISA). Bone formation was assessed by ELISA measurement of the N-terminal-mid-fragment as well as the intact serum osteocalcin (OCN-MID), thus omitting the influence of the instability of osteocalcin caused by the labile 6 amino acid C-terminal sequence. The women were divided into groups with high or low bone turnover according to the concentrations of urinary CrossLaps™ or OCN-MID. Women in the quartiles with the highest concentrations of CrossLaps [519 ± 119 μg/mmol (SD)] or OCN-MID [44.6 ± 7.5 ng/ml (SD)] had 10–16% lower spinal BMD compared with women in the lowest quartiles (CrossLaps 170 ± 48 μg/mmol (SD), and OCN-MID [22.1 ± 3.0 ng/ml (SD)] (P 〈 0.0004). The prevalences of spinal fracture were 25 to 29% in the lowest quartiles, whereas the prevalences in the highest quartiles were almost double—53–54% (P 〈 0.006). If the women were subgrouped according to spinal BMD and prevalence of spinal fracture, corresponding results were found. Women with a BMD less than 0.860 g/cm2, without or with spinal fracture (n = 136 and n = 142), had 36–43% higher concentration of CrossLaps (P= 0.0001) and 11–15% higher concentration of OCN-MID (P 〈 0.02), as compared with women with a BMD above 0.860 g/cm2 and no spinal fracture (n = 84). In conclusion, the results indicate a strong association among high bone turnover, low bone mass, and prevalence of spinal fracture, which supports the theory that high bone turnover is a risk factor for spinal fracture and osteoporosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900225
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