Effects of liposomal phophatidylserine on phagocytic uptake of liposomes by macrophage-like HL-60RG cells

The purpose of this work is to know the effect of surface properties of liposomes on their phagocytic uptake by macrophages. For this, liposomes were prepared by the Bangham technique from the mixture of phosphatidylcholine (PC) and cholesterol (Chol) incorporated either with phosphatidylserine (PS), phosphatidylethanolamine (PE) or phosphatidic acid (PA). The liposomes thus prepared had diameters in the range between 150 and 260 nm. Electric surface properties of the liposomes and the macrophages differentiated from HL-60RG cells were determined by measuring their electrophoretic mobilities. The phagocytic uptake of liposomes with different contents of PS, PE and PA by macrophage-like HL-60RG cells was investigated by measuring oxygen consumption associated with phagocytic uptake. The phagocytic activity was found to be the highest with the PC–Chol liposomes containing 7 mol% PS, but no significant effects were observed with PA- and PE-containing PC–Chol liposomes. As the uptake was independent of the electric surface property of liposomes, PS was concluded to be specifically important for phagocytic activity of macrophages.     

Interaction of tri-O-methyl-β-cyclodextrin with drugs

Summary The effect of tri-O-methyl--cyclodextrin(methyl--CD) on the partition coefficients of drugs, such as p-nitrophenol, salicylic acid, benzoic acid, and aspirin, was studied at 25°C. The partition coefficients of these drugs were increased linearly with methyl--CD concentration. The increase of partition coefficients was interpreted by the 11 complex formation between methyl--CD and the drug in CHCl₃ phase.The interaction between p-nitrophenol and methyl--CD in solution was studied by UV and PMR spectroscopies. It was concluded that p-nitrophenol is included in the cavity of methyl--CD in both aqueous solution and CHCl₃ solution.Inclusion compounds of these drugs with methyl--CD in the solid state were studied by X-ray diffractometry, IR spectroscopy, and DSC measurements. 11 crystalline inclusion compounds were obtained from hot water. It is also suggested that amorphous inclusion compound was obtained by the grinding of drug with methyl--CD.The dissolution rate and the bioavailability of ketoprofen were significantly increased in the presence of methyl--CD. The bioavailability of ketoprofen after oral administration with methyl--CD to rats was 3.7 times that of ketoprofen alone.     

Separation of technetium from rhenium by liquid-liquid extraction with potassium xanthate

A method is described for separating technetium from rhenium in hydrochloric acid medium by liquid-liquid extraction with potassium xanthate and carbon tetrachloride. The effects of the concentration of various acids, concentration of xanthate, different solvents and diverse ions have been investigated.     

Behavior of fatty acid during the incubation of bovine serum albumin. Entity of the serum albumin resistant to heat

The solution of bovine serum albumin, incubated at pH 9 (0.1 M Tris-EDTA-boric acid buffer in which 0.15 M KCl was contained) and 65 °C for 60 min, gave zones of undenatured monomer (component 1) and aggregates in the pattern of gel electrophoresis. The component 1, isolated from this solution, contained more fatty acids than the original albumin and than the mixture of aggregates. The aggregates contained substantially no fatty acids. This means that fatty acids are released, when the bovine albumin is denatured accompanying with intra- and intermolecular SH/S-S exchange reactions. Taking palmitic acid as a representative of the long chain fatty acid, a model experiment was performed. The bovine albumin, to which 6 palmitic acids were bound, did not cause the SH/S-S exchange reaction and was not denatured on incubation at pH 9 (0.1 M Tris-EDTA-boric acid buffer) and 65 °C. When the solution of “crystalline bovine albumin” (AF_0.9, A: albumin, F: long chain fatty acid) was incubated at pH 9 (0.1 M Tris-EDTA-boric acid buffer) and 65 °C, 20% of the albumin was not denatured even after prolonged incubation. Further, when the component 1 (AF_3.8), isolated from pre-incubated albumin solution, was incubated again at pH 9 and 65 °C, 58% of the albumin was not denatured even after sufficient time of incubation. Quantitative analysis reveals that the bovine albumin containing 6 fatty acids (AF₆) is not denatured at all, and is the entity of the albumin resistant to heat.     

Structure-activity relationships of dopamine- and norepinephrine-uptake inhibitors

Quantitative structure-activity relationship (QSAR) analysis of 3-phenyl-1-indanamines, 1-amino-4-aryltetralins, and 6-phenylpyrrolo[2,1-a] isoquinolines has been performed for catecholamine-uptake inhibition activities. Similar equations were obtained for these series of congeners indicating a common tendency that the increase in hydrophobicity of the substituents on the primary phenyl ring (ring C) enhances the activity, and the important aromatic ring which interacts with the receptor is this ring C. It was also indicated that the effect of the introduction of the second N-methyl group differs depending on the series of congeners. These results were used to characterize a binding model for a pharmacophore, which comprised a phenyl ring and a basic nitrogen. This model defined the necessary three-dimensional features leading to the uptake inhibition, and degree of fitness with this model predicted the strength of the activity. Furthermore, it appeared likely that a substituent existing in a specific region of the inhibitor molecule causes a steric hindrance with the receptor site and reduces the activity.     

Macro-azo-initiators composed of various polyesters: Their syntheses,thermal properties,and application to block copolymerization

Various aliphatic polyesters such as poly (ethyleneadipate), poly (tetramethylene adipate), poly (caprolactone), and poly (carbonate) were condensed with 4,4'-azobis-4-cyanopentanoyl chloride to prepare macro-azo-initiators. Their thermal properties, observed by differential scanning calorimetry, showed similar decomposition behavior to each other. Block copolymers containing each of these polyesters as a block segment combined with polystyrene or poly (methylmethacrylate) have been derived by the polymerization of monomers initiated with these macro-azo-initiators. © 1994 John Wiley & Sons, Inc.     

Miscibility and gas permeability of poly(ethylene-co-5,4 mol% 3,5,5-trimethylhexyl methacrylate)-polydimethyl-siloxane blends

 Blends of poly(ethylene- co-5.4 mol% 3,5,5-trimethylhexyl methacrylate) (PE-TMHM) with poly(dimethylsiloxane) (PDMS) were prepared in the PDMS content range from 0 to 20%. The miscibility was studied for PE-TMHM–PDMS blends by DSC, dynamic mechanical and microscopic spectroscopy, and the gas permeability was measured for O₂, N₂ and CO₂ as function of PDMS content. PE-TMHM and PDMS were partially miscible with each other below 20 wt% of PDMS content. The permeability coefficients (P) for O₂, N₂ and CO₂ were increased by the blending of PDMS to PE-TMHM. The change of P for O₂ with PDMS content well reflected the partially miscible phase separation behavior. Received: 10 June 1996 Accepted: 14 August 1996     

Effect of nonpolar field formed by polymer ligand on the oxidation of 2,6-xylenol catalyzed by Cu complexes

The oxidative polymerization catalyzed by Cu(II)-poly(vinylpyridine) derivatives and the effect of the nonpolar field formed by the polymer ligand on the catalysis was studied in dimethyl sulfoxide (DMSO) solvent. The catalytic activity of the Cu complex increases in the following order; Cu-(styrene-vinylpyridine copolymer) (St·VP) complex > Cu-partially quarternized (by benzyl chloride) poly(vinylpyridine)(BCQP) complex > Cu-poly(vinylpyridine) (PVP) complex > Cu-pyridine (Py) complex > Cu-partially quarternized (by ethyl bromide) poly(vinylpyridine) (EBQP) complex. This order is the same as that of the reoxidation rate constant of the catalyst. Acceleration of k_o process in Cu-St>VP and Cu-BCQP systems, where the active site is in the nonpolar field formed by the polymer ligand, is explained by an increase in strength of the coordination bonds.     

Searching ultimate nanometrology for AlOx thickness in magnetic tunnel junction by analytical electron microscopy and X-ray reflectometry.

Practical analyses of the structures of ultrathin multilayers in tunneling magneto resistance (TMR) and Magnetic Random Access Memory (MRAM) devices have been a challenging task because layers are very thin, just 1-2 nm thick. Particularly, the thinness (approximately 1 nm) and chemical properties of the AlOx barrier layer are critical to its magnetic tunneling property. We focused on evaluating the current TEM analytical methods by measuring the thickness and composition of an AlOx layer using several TEM instruments, that is, a round robin test, and cross-checked the thickness results with an X-ray reflectometry (XRR) method. The thickness measured by using HRTEM, HAADF-STEM, and zero-loss images was 1.1 nm, which agreed with the results from the XRR method. On the other hand, TEM-EELS measurements showed 1.8 nm for an oxygen 2D-EELS image and 3.0 nm for an oxygen spatially resolved EELS image, whereas the STEM-EDS line profile showed 2.5 nm in thickness. However, after improving the TEM-EELS measurements by acquiring time-resolved images, the measured thickness of the AlOx layer was improved from 1.8 nm to 1.4 nm for the oxygen 2D-EELS image and from 3.0 nm to 2.0 nm for the spatially resolved EELS image, respectively. Also the observed thickness from the EDS line profile was improved to 1.4 nm after more careful optimization of the experimental parameters. We found that EELS and EDS of one-dimensional line scans or two-dimensional elemental mapping gave a larger AlOx thickness even though much care was taken. The reasons for larger measured values can be found from several factors such as sample drift, beam damage, probe size, beam delocalization, and multiple scattering for the EDS images, and chromatic aberration, diffraction limit due to the aperture, delocalization, alignment between layered direction in samples, and energy dispersion direction in the EELS instrument for EELS images. In the case of STEM-EDS mapping with focused nanoprobes, it is always necessary to reduce beam damage and sample drift while trying to maintain the signal-to-noise (S/N) ratio as high as possible. Also we confirmed that the time-resolved TEM-EELS acquisition technique improves S/N ratios of elemental maps without blurring the images.