ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Bone  (29)
  • Calcium  (24)
  • Springer  (52)
  • 1980-1984  (36)
  • 1975-1979  (16)
Collection
Keywords
Publisher
  • Springer  (52)
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Rhythmic dentinogenesis in the rabbit incisor: Allometric aspects (1980)
    Springer
    Calcified tissue international 32 (1980), S. 45-53 
    Details
    ISSN: 1432-0827
    Keywords: Dentin ; Periodicity ; Allometry ; Calcium ; Sulfur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have described differences in the aspects of biological rhythms for calcium and sulfur deposition on the labial and lingual sides of the growing rabbit incisor, where growth occurs along a spiral axis. The calcium oscillations appear to be smoother on the labial side than on the lingual side. The lingual side is characterized by high-frequency rhythms with high amplitudes which possess the greatest percent of the power (Fourier analysis). These observations also reflect a difference in behavior of the mean Ca concentration across the labial and lingual sides. Sulfur rhythms on the labial side have higher amplitudes than those on the lingual side, but systematic differences in distribution of power between high and low frequencies is not as pronounced as in the case of Ca. The differences in Ca rhythms reflect differences in the growth rates of incisors on either side of the spiral axis. The labial side grows slightly faster than the lingual side, and its odontoblasts secrete Ca along the spiral axis and toward the pulp cavity at the same time. Thus the resultant direction of growth is more nearly opposite the extension of the occlusal end on the labial side, and Ca is consequently deposited over a wider area relative to that on the lingual surfaces. On the lingual side, Ca is deposited within a more limited area, and growth must therefore be continuous at high frequencies. The distribution of Ca on both sides of the tooth reflects these differences in growth rate and periodicity in two ways. First, given a unit area of tooth, the calcium concentration on the labial side is less than that of the lingual side. Second, whereas the calcium concentration on the labial side declines rapidly from the enamel-dentin junction to the pulp cavity, it is uniformly high across the lingual side because its growth is more continuous at high frequencies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408520
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Rhythmic dentinogenesis in the rabbit incisor: Circadian, ultradian, and infradian periods (1980)
    Springer
    Calcified tissue international 32 (1980), S. 29-44 
    Details
    ISSN: 1432-0827
    Keywords: Rabbit ; Dentin ; Calcium ; Sulfur ; Periodicity ; Circadian ; Ultradian
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have identified a variety of biological rhythms involved in the apposition and mineralization of dentin in the rabbit incisor. Animals were injected during the day or night with lead acetate at 2-week intervals—to provide biological time markers in forming dentin—and transverse undecalcified sections of the lower incisors were prepared for electron microprobe analysis. The positions of the lead markers were identified, and the continuous distribution of calcium and sulfur was measured at 1 µm intervals between the markers. In thin sections stained with hematoxylin after decalcification, the widths of a series of structural increments (bands) were measured with an ocular micrometer. Fourier analysis of the data revealed spectra of structural and compositional rhythms with a range of periodicities which extended from a matter of hours [ultradian (〈24 h)] to days [infradian (〉24 h) and circadian (approximately 24 h)]. The structural and compositional rhythms appeared to be independent to the extent that they did not necessarily have the same periods, or amplitudes. Nor were there simple phase relationships between all of the rhythms. At some times, Ca and S fluctuations are inversely proportional (180° out of phase), but in other cases they are directly proportional or out of phase by varying degrees other than 180°. The analyses thus suggest that calcium and sulfur deposition (representing mineral and glycosaminoglycan deposition, respectively) are not simply inversely proportional, and that the hematoxylin-stained structural increments did not solely reflect differences in the distribution of the mineral components in dentin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408519
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Bone histomorphometric reproducibility in normal patients (1981)
    Springer
    Calcified tissue international 33 (1981), S. 369-374 
    Details
    ISSN: 1432-0827
    Keywords: Histomorphometry ; Bone ; Reproducibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary To study bone histomorphometry reproducibility in normal subjects, we performed during orthopedic surgery bone biopsies in 16 post-menopausal women. Each woman had four bone biopsies, two at the usual site in the iliac crest, one on the left and one on the right side, and two other biopsies just behind the usual site, one at each side. We performed measurements of trabecular bone volume, relative osteoid volume, osteoid surfaces, osteoclastic resorption surfaces and calcification front. The average values of the 16 patients were compared, on the one hand, two by two, by a student test, and on the other hand, by a variance analysis. By these two methods the results showed no significant difference between the average values of the 16 patients at each location for any of the histomorphometric parameters studied. However, there was a location variation which was estimated by the intra-individual variation for a given patient. On the other hand, we calculated from the variance analysis the location variance for a group of 10 to 100 patients. In any case all the parameters had a location variation which was high for osteoclastic resorption surfaces and relative osteoid volume when expressed in % of the absolute value of these parameters. The variation of the trabecular bone volume was 0–46. 15% (95% confident limit interval) in a single patient and the hypothetical value of the location variation was 41.6% for a group of 10 patients and 13.0% for a group of 100 patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409458
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Tentacle contraction inDiscophrya collini: The effects of ionophore A23187 and ruthenium red on Ca2+-induced contraction and uptake of extracellular calcium (1984)
    Springer
    Protoplasma 122 (1984), S. 125-131 
    Details
    ISSN: 1615-6102
    Keywords: Calcium ; Contraction ; Discophrya ; Ionophore A23187 ; Ruthenium red ; Tentacles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The tentacles of the suctorian protozoonDiscophrya collini are stimulated to contract by externally applied Ca2+. The role of extracellular Ca2+ in tentacle contraction was studied by monitoring45Ca2+ uptake, using ionophore A23187 to facilitate membrane transport of calcium and ruthenium red (RR) as an inhibitor of transport. The degree of tentacle retraction was dependent upon external Ca2+ concentration and studies with45Ca2+ using scintillation counting indicated a linear relationship between external Ca2+ concentration and Ca2+ uptake. Uptake of Ca2+ was enhanced in the presence of the ionophore while RR caused little inhibition.45Ca2+ uptake was only partially inhibited by RR when cells were subjected to a Ca2+, ionophore and RR mixture. Grain counts from light microscope autoradiographs after treatment of cells with45Ca2+/ionophore,45Ca2+/RR or45Ca2+ alone showed heavy, light and intermediate labelling respectively. In all instances the grains were evenly distributed within the cell. These observations are interpreted as supporting the suggestion that the ionophore enhances both the uptake of extracellular Ca2+ and release of Ca2+from an internal source, while the RR could only partially prevent movement of Ca2+ through the plasma mebrane. A model is presented suggesting that tentacle retraction is mediated by cytosolic Ca2+ levels which are determined by the fluxing of Ca2+ across the plasma membrane and the membrane of elongate dense bodies which act as internal Ca2+ reservoirs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279445
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The intestinal handling of calcium by the rat in vivo, as affected by cortisol. Effect of dietary calcium supplements (1978)
    Springer
    Calcified tissue international 25 (1978), S. 1-6 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Intestine ; Growth ; Cortisol ; Hydroxyproline ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This paper reports the effects of cortisol on intestinal management of calcium and on related changes on bone metabolism. Five groups of 12 rats each fed a standard diet (0.8% Ca) received 2, 6, 16, 32, and 128 mg/kg/day of cortisol hemisuccinate, subcutaneously. After 16 days, intestinal absorption and excretion of Ca were measured with the aid of45Ca. True Ca absorption increased as a function of dose up to 16 mg/kg/day and remained high with the larger doses. Endogenous fecal Ca excretion increased exponentially as a function of the dose from 16 mg/kg/day onwards. Therefore, a dual effect was observed: (a) an increase in true Ca absorption at low cortisol doses (which increased net Ca absorption); and (b) an increase in endogenous fecal Ca excretion at high doses (which reduced net Ca absorption). In no case was a depression of true Ca absorption observed. Growth rate and food conversion efficiency were depressed only with a cortisol dose of 128 mg/kg/day. The urinary excretion of hydroxyproline, pyrophosphate, and aminopolysaccharides decreased with low doses and increased above normal levels with the highest dose. When animals treated with 128 mg/kg/day of cortisol were fed Ca-enriched diets, net Ca absorption improved. Simultaneously, growth rate and food conversion efficiency approached normal values. In these experiments, net absorption of Ca was found to be inversely related to urinary excretion of hydroxyproline. The urinary rate of excretion of hydroxyproline is suggested as an indicator of the effect of a Ca supplement on cortisol affected connective tissue turnover.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010743
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    What should bones be designed to do? (1984)
    Springer
    Calcified tissue international 36 (1984), S. S7 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Mechanical function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The variety of different mechanical functions required of whole bones is discussed. Often, the design optimizing the structure for one function is not optimal for another function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02406127
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Neutral peptidase activities in matrix vesicles from bovine fetal alveolar bone and dog osteosarcoma (1983)
    Springer
    Calcified tissue international 35 (1983), S. 791-797 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Osteosarcoma ; Matrix vesicles ; Alkaline phosphatase ; Aminopeptidase ; Naphthylamidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Extracellular matrix vesicles from bovine fetal alveolar bone and from a dog osteosarcoma were isolated by differential centrifugation and then fractionated on a discontinuous sucrose density gradient. The fractions were examined by electron microscopy and were analyzed for protein, alkaline phosphatase, aminotripeptidase, and four different β-naphthylamidase activities. The low-density peak of enzyme activities was shown by electron microscopy to be much more homogeneous than the crude matrix vesicle fraction. Two major peaks of protein and enzyme activities were present, one in the high and one in the low density layers. There was good correlation between the activities of alkaline phosphatase and the various peptidases in the fractions from the sucrose density gradient. These results indicate a coexistence of peptidase and alkaline phosphatase in matrix vesicles. On the other hand, there was generally no correlation between the peptidase and alkaline phosphatase activities in vesicular specimens from bovine liver obtained in the same way. Most of the peptidase activity and about half of the alkaline phosphatase activity were solubilized from bone matrix vesicles by detergents. The extracted alkaline phosphatase and alanyl β-naphthylamidase activities were separated from each other on a DEAE-cellulose column.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405125
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Human vertebral bone: Relation of strength, porosity, and mineralization to fluoride content (1980)
    Springer
    Calcified tissue international 32 (1980), S. 189-194 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Fluoride ; Strength ; Porosity ; Mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Radiographically normal vertebral bone cylinders from 80 male subjects were tested mechanically by static compression and analyzed for porosity, fluoride and ash content. As a group, they had low fluoride content, suggesting little prior intake, consonent with this geographic area. Nevertheless, increasing levels of fluoride were associated with bulkier bone, less porosity, and less mineral per unit of bone, which in direction though not degree suggested changes similar to those of osteomalacia and opposite from those of osteoporosis without apparent threshold. The higher fluoride hard tissue was weaker in static tests than that with less fluoride, but the increased bulk apparently offset this, resulting in bones of unchanged static strength. Hence, water fluoridation should not alter static bone strength. There has, however, been a recent report suggesting that increased mineralization of bone renders it more brittle and thus more likely to fracture on impact. Therefore, the possibility that fluoridation may increase impact resistance by lessening mineralization can be entertained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408540
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Failure to detect an amorphous calcium-phosphate solid phase in bone mineral: A radial distribution function study (1984)
    Springer
    Calcified tissue international 36 (1984), S. 291-301 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Mineral ; Amorphous calcium phosphate ; X-ray diffraction ; Radial distribution function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary X-ray diffraction radial distribution function analysis was used to determine if a significant amount of an amorphous solid phase of calcium phosphate exists in bone, and if so, whether the amount varies as a function of age and maturation. Unfractionated cortical bone from embryonic and posthatch chicks of various ages and a low-density fraction of embryonic bone were studied. No evidence was found for the presence of an amorphous solid phase of calcium phosphate in any of the samples studied, including the recently deposited bone mineral of the low density fraction of embryonic bone. As little as 12.5% of synthetic amorphous calcium phosphate (ACP) added to bone was readily detected by the radial distribution function technique used. The results clearly indicate that the concept that ACP is the initial solid mineral phase deposited in bone, and the major mineral constituent of young bone is no longer tenable. The concept does not provide an accurate description of the nature of the initial bone mineral deposited, or the changes that occur with maturation, nor can it acount for the compositional and X-ray diffraction changes that the mineral component undergoes during maturation and aging.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405333
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Effects of 1α-hydroxy vitamin D3 on the rachitic chick intestine: A comparison to the effects of 1,25-dihydroxyvitamin D3 (1980)
    Springer
    Calcified tissue international 32 (1980), S. 9-17 
    Details
    ISSN: 1432-0827
    Keywords: 1α-Hydroxy vitamin D3 ; 1,25-Dihydroxyvitamin D3 ; Calcium ; Transport ; Intestine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The timed sequence of events following the oral administration of 1α-hydroxy vitamin D3 (1αOHD3) to rachitic chicks was compared to that following a comparable dose of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3). RNA polymerase activity was maximally increased 20% by 1αOHD3 within 1 to 2 h and returned to control values after 8 h. Alkaline phosphatase activity was stimulated by 4 h and was maximal (3- to 5-fold increase) at 24 h. Calcium binding protein (CaBP) was detected initially within epithelial cells at the proximal end of the villus (just above the crypt) 6 to 8 h after 1αOHD3 administration, in epithelial cells lining the proximal half of the villus by 24 h, and in epithelial cells along nearly the entire villus by 48 h. At no time did goblet cells contain CaBP. Serum calcium concentrations were significantly elevated in 2 h and maximal by 12 h (an increase of 3.6 mg/dl). Calcium accumulation by the intestinal mucosa in vitro was increased by 6 to 8 h and maximal (60% increase over controls) at 24 h. Phosphate accumulation by the intestinal mucosa in vitro was increased by 6 h and maximal (105% increase over controls) between 8 and 24 h. 1,25(OH)2D3 increased CaBP and calcium accumulation by 4 h, 2 h sooner than did 1αOHD3. 1,25(OH)2D3 decreased serum calcium levels and increased serum phosphate levels at 2 h unlike 1αOHD3. No difference in the effects of these compounds on alkaline phosphatase activity, RNA polymerase activity, and phosphate accumulation could be demonstrated. These results are consistent with the possibility that 1αOHD3 may not require conversion to 1,25(OH)2D3 for all of its biological effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408517
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...