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 Ca mobilization  (2)
  • Atomic, Molecular and Optical Physics  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Calcium regulating activity of 26,27-dialkyl analogs of 1α,25-dihydroxyvitamin D3 (1992)
    Springer
    Calcified tissue international 51 (1992), S. 218-222 
    Details
    ISSN: 1432-0827
    Keywords: Bone resorption ; Osteoclast formation ; Bone Ca mobilization ; 26,27-Dialkyl-1α,25-dihydroxyvitamin ; D3-Osteopenia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A series of analogs of 1α,25-dihydroxyvitamin D3[1,25(OH)2D3] with alkyl substitutions in 26- and 27-positions were tested for calcium (Ca) regulating activity. The potencies of dialkyl analogs in stimulating bone resorption in neonatal mouse calvaria cultures were the highest in 1α,25-dihydroxy-26,27-dimethylvitamin D3[1,25(OH)2-(Me)2D3], followed by 1,25(OH)2D3, 1α,25-dihydroxy-26,27-diethylvitamin D3[1,25(OH)2(Et)2D3], and 1α,25-dihydroxy-26,27-dipropylvitamin D3[1,25(OH)2(Pr)2D3] in that order. A similar order of potential regarding formation of osteoclast-like cells in mouse bone marrow cell cultures and on bone Ca mobilization with long-term vitamin D-deficient rats was observed in the same series. The relative potencies of 1,25(OH)2D3, 1,25(OH)2(Me)2D3, 1,25(OH)2(Et)2D3, and 1,25(OH)2(Pr)2D3 in competing with 1,25(OH)2D3 for binding to chick intestinal cytosol receptors were 1:1:0.16:0.036. A similar order of potential in case of intestinal Ca transport in situ was observed in the same series. The potencies of dialkyl analogs in competing with 25-hydroxy-vitamin D3 for binding to rat serum vitamin D binding protein were much lower than that of 1,25(OH)2D3. Effect of 1,25(OH)2(Me)2D3 on osteopenia in rats induced by ovariectomy and right sciatic neurotomy was higher than that of 1,25(OH)2D3. From these results, the lengthening by one carbon at 26- and 27-positions was shown to maintain the Ca regulatory activity of 1,25(OH)2D3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334550
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Calcium regulating activity of 24a-homo-24,24-difluoro-1α,25-dihydroxyvitamin D3 and 26,27-dimethyl-24,24-difluoro-1α,25-dihydroxyvitamin D3 (1993)
    Springer
    Calcified tissue international 53 (1993), S. 318-323 
    Details
    ISSN: 1432-0827
    Keywords: Bone resorption ; Osteoclast formation ; Bone Ca mobilization ; Fluoro analogs of 1,25(OH)2D3 ; Osteopenia prevention
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Two fluoro analogs of 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3], 24a-homo-24,24-difluoro-1α,25-dihydroxyvitamin D3 [24aF2-homo-1,25(OH)2D3], and 26,27-dimethyl-24,24-difluoro-1α,25-dihydroxyvitamin D3 [24F2-1,25(OH)2(Me)2D3] were examined for calcium (Ca)-regulating activity. The objective of the present study was to determine whether or not fluoro substitution at 24-position would alter activities of the original compounds, that is, 26,27-dimethyl 1α, 25-dihydroxyvitamin. D3[1,25(OH)2 (Me)2D3] and 24-homo-1α,25-dihydroxyvitaminD3[24homo-1,25(OH)2D3], respectively. The relative activities of 24aF2-homo-1,25(OH)2D3, 24F2-1,25(OH)2(Me)2D3, and 1,25(OH)2D3 in competing with 1,25(OH)2D3 for binding to chick intestinal cytosol receptor were 0.28:0.5:1.0. The relative potencies of the same series of compounds in competition for the vitamin D-deficient rat serum binding sites were 0.04:0.15:1. Bone-resorbing activities of two fluoro analogs in cultures of neonatal mouse parietal bones were more potent than that of 1,25(OH)2D3. Similar results were recognized in stimulating activities of osteoclast-like cell formation. Responses of two fluoro analogs to intestinal Ca absorption were similar to that of 1,25(OH)2D3. The potencies of 1,25(OH)2D3. and its fluoro analogs in bone Ca mobilization were the highest with 1,25(OH)2D3. followed by 24F2 1,25(OH)2(Me)2D3 and 24aF2-homo-1,25(OH)2D3, in that order. From these results and the data of Paulson et al. [24], fluoro substitution in 24-position of 1,25(OH)2D3. apparently does not alter their activities, hence, the fluoro substitution at 24-position of 1,25(OH)2D3. and the elongation of side chain of 1,25(OH)2D3. may not intensify Ca-regulating activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01351836
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    AM1 calculation of hydration to aldehyde group in nitro-substituted benzaldehydes (1993)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 45 (1993), S. 97-104 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydration to the aldehyde group in nitro-substituted benzaldehydes was studied theoretically by using an AM1 method. The calculated values of activation energy and heat of reaction showed good correlations with the experimental values of rate constants and equilibrium constants, respectively. To examine the hydration mechanism, localized molecular orbitals were calculated. Furthermore, expression of the molecular orbitals of supermolecular complexes in terms of occupied and vacant orbitals of the component molecules elucidated that the interaction between the lonepair orbital of water and the antibonding C—O π-orbital of aldehyde was important. 2,6-DNBAl was concluded to be less reactive toward water than was 2.4-DNBAl. This is consistent with the experimental result that the mutagenic activity of 2,4-DNBAl depends not only on the reduction of the nitro group by a bacterial enzyme but also on the acetyl conjugation, but that in the case of 2,6-DNBAl the mutagenic activity is manifested through the reduction by a bacterial enzyme. © 1993 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560450112
    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...