scholarly journals Dihydroceramide Desaturase Inhibition by a Cyclopropanated Dihydroceramide Analog in Cultured Keratinocytes

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Susanne Brodesser ◽  
Thomas Kolter
Keyword(s):  
Double Bond ◽  
Chemical Synthesis ◽  
Cultured Cells ◽  
Hydrogen Atoms ◽  
Differentiation Markers ◽  
Cultured Keratinocytes ◽  
Proliferation And Differentiation ◽  
Dihydroceramide Desaturase ◽  
Methylene Group

Most mammalian sphingolipids contain a 4,5-(E)-double bond. We report on the chemical synthesis of a dihydroceramide derivative that prevents the introduction of the double bond into sphingolipids. Minimal alteration of the parent structure by formally replacing the hydrogen atoms in the 5- and in the 6-position of the sphinganine backbone by a methylene group leads to an inhibitor of dihydroceramide desaturase in cultured cells. In the presence of 10–50 μM of compound (1), levels of biosynthetically formed dihydroceramide and—surprisingly—also of phytoceramide are elevated at the expense of ceramide. The cells respond to the lack of unsaturated sphingolipids by an elevation of mRNAs of enzymes required for sphingosine formation. At the same time, the analysis of proliferation and differentiation markers indicates that the sphingolipid double bond is required to keep the cells in a differentiated state.

A Novel Scheme for the Synthesis of 21-Acetoxypregna-1,4,9(11)-triene- 17α,21-diol-3,20-dione from 9α-Hydroxyandrostenedione

2020 ◽  
Vol 16 (5) ◽  
pp. 606-610
Author(s):  
Nguyen T. Diep ◽  
Luu D. Huy
Keyword(s):  
Double Bond ◽  
Chemical Synthesis ◽  
Economic Efficiency ◽  
Final Stage ◽  
Side Chain ◽  
Entire Process ◽  
Drug Synthesis ◽  
First Time

Background: Vietnam currently imports up to 90% of the pharmaceuticals it consumes and 100% of the steroid-based pharmaceuticals. The ability for efficient chemical synthesis of the steroids could create commercial opportunities to address this issue. Synthesis of 21-acetoxypregna-1,4,9(11)- triene-17α,21-diol-3,20-dione is considered a key intermediate in the scheme of steroidal drug synthesis. Previous synthesis attempts of such steroids (corticoids) introduce a double bond at C-1(2) in the final stage of synthesis, which delivers a poor yield and reduces the economic efficiency of the process. Objective: To study and develop a novel and effective method for the synthesis of 21-acetoxypregna- 1,4,9(11)-triene-17α,21-diol-3,20-dione. Methods: Using 9α-hydroxyandrostenedione as a substrate chemical synthesis was performed as follows: pregnane side chain construction at C-17 (acetylene method), introduction of C-1(2) double bond (using SeO2), epimerization of C-17 (via 17-ONO2 ester) and Stork’s iodination. Results: 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione was prepared from 9α- hydroxyandrostenedione with an improved yield compared to previous attempts. Conclusion: Here, 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione has been synthesized from 9α-hydroxyandrostenedione based on a novel, effective and commercially feasible scheme. The introduction of the C-1(2) double bond at an earlier stage of the synthesis has increased the economic efficiency of the entire process. For the first time, the indirect epimerization mechanism has been clarified along with the configuration of the C-17 stereo-center which has been confirmed using NOESY data.

scholarly journals Fluid Flow Mechanical Stimulation-Assisted Cartridge Device for the Osteogenic Differentiation of Human Mesenchymal Stem Cells

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 927
Author(s):  
Ki-Taek Lim ◽  
Dinesh-K. Patel ◽  
Sayan-Deb Dutta ◽  
Keya Ganguly
Keyword(s):  
Tissue Engineering ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Fluid Flow ◽  
Osteogenic Differentiation ◽  
Flow Condition ◽  
Cultured Cells ◽  
Human Mesenchymal Stem Cells ◽  
Proliferation And Differentiation ◽  
Static Conditions

Human mesenchymal stem cells (hMSCs) have the potential to differentiate into different types of mesodermal tissues. In vitro proliferation and differentiation of hMSCs are necessary for bone regeneration in tissue engineering. The present study aimed to design and develop a fluid flow mechanically-assisted cartridge device to enhance the osteogenic differentiation of hMSCs. We used the fluorescence-activated cell-sorting method to analyze the multipotent properties of hMSCs and found that the cultured cells retained their stemness potential. We also evaluated the cell viabilities of the cultured cells via water-soluble tetrazolium salt 1 (WST-1) assay under different rates of flow (0.035, 0.21, and 0.35 mL/min) and static conditions and found that the cell growth rate was approximately 12% higher in the 0.035 mL/min flow condition than the other conditions. Moreover, the cultured cells were healthy and adhered properly to the culture substrate. Enhanced mineralization and alkaline phosphatase activity were also observed under different perfusion conditions compared to the static conditions, indicating that the applied conditions play important roles in the proliferation and differentiation of hMSCs. Furthermore, we determined the expression levels of osteogenesis-related genes, including the runt-related protein 2 (Runx2), collagen type I (Col1), osteopontin (OPN), and osteocalcin (OCN), under various perfusion vis-à-vis static conditions and found that they were significantly affected by the applied conditions. Furthermore, the fluorescence intensities of OCN and OPN osteogenic gene markers were found to be enhanced in the 0.035 mL/min flow condition compared to the control, indicating that it was a suitable condition for osteogenic differentiation. Taken together, the findings of this study reveal that the developed cartridge device promotes the proliferation and differentiation of hMSCs and can potentially be used in the field of tissue engineering.

Photolyse du butène-1 dans l'ultraviolet à vide

1973 ◽  
Vol 51 (17) ◽  
pp. 2853-2859 ◽  
Author(s):  
Guy J. Collin
Keyword(s):  
Double Bond ◽  
Hydrogen Atom ◽  
Kinetic Energy ◽  
Thermal Energy ◽  
Hydrogen Atoms ◽  
Excited Molecules

The vacuum u.v. photolysis of 1 -butene was studied in the 147–105 nm region. The main products formed from the fragmentation of excited molecules are allene, 1,3-and 1,2-butadienes, ethylene, and acetylene. The addition of a hydrogen atom to the double bond produces mainly secondary butyl radicals (91%) at 147 nm. At 123.6 nm, this proportion becomes 82%. Thus at shorter wavelengths (10 and 11.6–11.8 eV), hydrogen atoms are produced with a kinetic energy higher than the thermal energy.

Photolyse de pentène-1 dans l'ultraviolet à vide

1973 ◽  
Vol 51 (5) ◽  
pp. 724-731 ◽  
Author(s):  
Patrick M. Perrin ◽  
Guy J. Collin
Keyword(s):  
Double Bond ◽  
Low Pressure ◽  
Hydrogen Atoms ◽  
Ethyl Radical ◽  
Excited Molecules

Photolysis of 1-pentene molecules at 8.4 eV (xenon photolysis) and 10.0 eV (krypton photolysis) was studied. Excited molecules decompose to produce mainly ethylene, propadiene, 1,3-butadiene, acetylene, and other minor products. Hydrogen atoms add to the double bond of the monomer and the resulting excited pentyl radical decomposes at low pressure (P < 1 Torr) into propene and ethyl radical. Isomerization of excited 1-pentene molecules is unimportant at these energies.

scholarly journals The introduction of the C-22–C-23 ethylenic linkage in ergosterol biosynthesis

1968 ◽  
Vol 106 (3) ◽  
pp. 623-626 ◽  
Author(s):  
M Akhtar ◽  
M. A. Parvez ◽  
P. F. Hunt
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chemical Synthesis ◽  
Good Yield ◽  
The Other ◽  
Side Chain ◽  
Ergosterol Biosynthesis ◽  
Hydrogen Atoms ◽  
Whole Cells ◽  
C 23 ◽  
Methylene Derivative

Methods for the chemical synthesis of [23−3H2]lanosterol, [23,25−3H3]24-methyldihydrolanosterol and [24,28−3H2]24-methyldihydrolanosterol are described. It is shown that, in the biosynthesis of ergosterol from [26,27−14C2,23−3H2]lanosterol by the whole cells of Saccharomyces cerevisiae, one of the original C-23 hydrogen atoms is lost and the other is retained at C-23 of ergosterol. It is also shown that 24-methyldihydrolanosterol is converted into ergosterol in good yield and without prior conversion into a 24-methylene derivative. On the basis of these results possible pathways for the formation of the ergosterol side chain from a 24-methylene side chain are discussed.

The construction of 1,3-dienes containing an E-double bond and an exo-methylene group

1995 ◽  
pp. 1497 ◽  
Author(s):  
James J. Eshelby ◽  
Philip J. Parsons ◽  
Nan C. Sillars ◽  
Patrick J. Crowley
Keyword(s):  
Double Bond ◽  
Methylene Group

Investigation of the mobility of methylene group hydrogen atoms in some derivatives of 2-iminothiazolidin-4-one

1967 ◽  
Vol 3 (2) ◽  
pp. 516-518
Author(s):  
I. I. Chizhevskaya ◽  
R. S. Kharchenko ◽  
N. N. Khovratovich
Keyword(s):  
Hydrogen Atoms ◽  
Derivatives Of ◽  
Methylene Group

Tumour suppressor gene products, proliferation, and differentiation markers in lung neuroendocrine neoplasms

1992 ◽  
Vol 166 (4) ◽  
pp. 343-350 ◽  
Author(s):  
Mattia Barbareschi ◽  
Salvatore Girlando ◽  
Francesco A. Mauri ◽  
Gianluigi Arrigoni ◽  
Licia Laurino ◽  
...  
Keyword(s):  
Suppressor Gene ◽  
Tumour Suppressor Gene ◽  
Tumour Suppressor ◽  
Neuroendocrine Neoplasms ◽  
Gene Products ◽  
Differentiation Markers ◽  
Proliferation And Differentiation
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