Effect of cholesterol and other additives on viscosity, self-diffusion coefficient, and intramolecular movements of oleic acid

It has been empirically known that cholesterol largely increases the viscosity of oleic acid. To clarify the mechanism of the effect of cholesterol on the intermolecular and the intramolecular (segmental) movements of oleic acid in the liquid state, we measured density, viscosity, IR, 1H NMR chemical shift, self-diffusion coefficient, and 13C NMR spin-lattice relaxation time for the liquid samples of oleic acid containing a small amount of cholesterol. Furthermore, the above measurements were also carried out for the samples of oleic acid containing a small amount of cholestanol, cholestane, cholesteryl oleate, ethanol, or benzene. Cholesterol, possessing one OH group and one double bond in its molecular structure, largely increased the viscosity and reduced the self-diffusion and the intramolecular movement of oleic acid. Cholestanol, possessing one OH group but not a double bond, and cholesteryl oleate, not possessing an OH group, also reduced the self-diffusion and the intramolecular movement; cholestane, not possessing an OH group, slightly reduced the self-diffusion and the intramolecular movements. In contrast with these sterols, ethanol and benzene reduced the viscosity and increased the self-diffusion and the intramolecular movements. In addition, cholesterol and ethanol, both having one OH group, promoted the upfield shift of the 1H NMR signal of the carboxyl group of oleic acid; IR difference spectra for the cholesterol/oleic acid system quite resemble those for the ethanol/oleic acid system. These results suggest that oleic acid makes a complex with cholesterol as well as with ethanol. On the basis of the formation of the complex, we have revealed the role and the functional mechanism of cholesterol to the intermolecular and the intramolecular movements of oleic acid in the liquid state.     

Gas chromatographic-mass spectrometric determination of macrolide antibiotics in beef and pork using single ion monitoring

A gas chromatographic-mass spectrometric (GC-MS) method using single ion monitoring (SIM) is described for the determination of residual macrolide antibiotics, oleandomycin, kitasamycin, spiramycin and tylosin, in beef and pork. For GC-MS determination, oleandomycin is acid hydrolysed to desoleandomycin and acetylated, in the same way as erythromycin. However, for elution from a GC column, the carbon-carbon double bonds in the antibiotics must be hydrogenated to single bonds before acid hydrolysis. Kitasamycin and spiramycin are therefore converted into hydroforocidine acetate and tylosin into hydro-O-mycaminosyl tylonolide acetate, which are determined by GC-MS with SIM.     

Protective effects of cyclodextrins on edaravone degradation induced by atmospheric oxygen or additive oxidant

Journal of Inclusion Phenomena and Macrocyclic Chemistry - Antioxidants scavenge free radicals and may help prevent disease. However, due to poor stability, continuous intake is required. This...     

A new protecting group ‘3,5-O-sulfinyl’ for xylo-nucleosides. A simple and efficient synthesis of 3-amino-3-deoxyadenosine (a puromycin intermediate), 2,2-anhydro-pyrimidine nucleosides and 2,3-anhydro-adenosine

We developed a new protecting group, the cyclic sulfite for the protection of the 3^′,5^′-dihydroxy group of nucleosides. Seven cyclic sulfites, 4a-c, 5a-b, and 6a-b were prepared in high yields from the corresponding xylo-uridines 1 and 2, and xylo-adenosines 3 with thionyl chloride, respectively. Synthesis of the puromycin intermediate 8 was carried out by deprotection of the sulfite moiety through an intramolecular cyclization of the 2^′-α-carbamate 7.     

Effects of vascular endothelial growth factor (VEGF) and chondroitin sulfate A on human monocytic THP-1 cell migration

Angiogenesis serves as a crucial factor in disease development and progression, such as cancer metastasis, and monocyte migration is one of the key steps for angiogenesis. Therapeutic modulation of angiogenesis is a promising new therapeutic avenue under investigation. In this study, effects of vascular endothelial growth factor (VEGF) and chondroitin sulfate A on monocyte migration were investigated. Human monocytic THP-1 cells were from Riken Cell Bank (Tsukuba, Japan) and vascular endothelial cells (VECs) were obtained from swine thoracic aorta. The migration experimental system was adapted from Falcon™ Cell Culture Inserts with pore sizes of 3 and 8 μm cultured endothelial cells or not on the insert polyethylene terephthalate (PET) membranes. Four VEGF concentrations (0, 10, 50 and 100 ng/ml) and three concentrations of chondroitin sulfate A (0, 1.25 and 5.0 mg/ml) were used to investigate their effects on THP-1 cell migration ability through PET membranes and VECs monolayer. The THP-1 cell migration was evaluated by counting the number of migrated cells related to the total number of cells under a microscope. We counted the migration cells every 1 h on a Tatai-type hemocytometer using an inverted microscope for total 7 h. For inserts with pore sizes of 3 and 8 μm, the THP-1 cell migration increased with VEGF concentrations; however, cell migration decreased with the chondroitin sulfate A concentration. Our results demonstrated that VEGF accelerated monocyte migration through endothelial monolayer and chondroitin sulfate A is an effective inhibitor of monocyte migration for angiogenesis.