Synthesis and anti-HIV activity of 3-alkylamido-3-deoxy-betulinic acid derivatives

3-Alkylamido-3-deoxy-betulinic acids were synthesized and evaluated for anti-HIV activity as part of the structure-activity relationship study of the potent anti-HIV agent 3-O-(3',3'-dimethyl)-succinyl-betulinic acid (DSB) (2). 3Alpha-diglycorylamide-3-deoxy-betulinic acid demonstrated relatively potent anti-HIV activity (EC50 0.24 microm, TI 728). However, replacing the ester group at C-3 in 2 and its analogues with an amido group yielded inactive or much less potent compounds against HIV replication, indicating that the ester group at C-3 in 2-4 is essential for potent anti-HIV activity.     

Influence of drawing and heat treatment on surface free energies of polyethylene terephthalate fibers

The surface free energies of polyethylene terepthalate fibers with different draw ratios were experimentally determined by contact angle measurements inn-alkane/water systems. The dispersive component of the surface free energy increased with increasing draw ratio, whereas the nondispersive one remained almost constant. After heat treatment, the dispersive surface free energy increased, but was reduced above 140°C. The nondispersive component increased by heat treatment at 190°C. The increases in the density and birefringence of the fibres due to the drawing and heat treatment suggested that the increase in the dispersive surface free energy was caused by the increase in the atomic density at the fiber surface due to drawing and heat treatment. ESCA results indicated that the increment in the nondispersive surface free energy due to heat treatment was caused by the addition of functional groups to the fiber surface due to heat treatment.     

Determination of dispersive and nondispersive components of the surface free energy of glass fibers

The dispersive component _s ^d of the surface free energy of glass fibers and its interaction energy with alkanes, benzene, 1-nitropropane, ethyleneglycol, glycerol, formamide, and water were quantitatively determined by the tensiometric method within two liquids. The values of nondispersive interaction energy I _SL ^p were found to be a linear function of the square root of the nondispersive component of the surface free energy of liquids. This suggests that the nondispersive interaction energy may be represented by the geometric mean of the nondispersive component of the surface free energy of a solid and a liquid. The slope gave the nondispersive component _s ^p of the surface free energy. The _s ^p values are 33 and 14 mJ/m² for the untreated and aminosilane-treated fibers, respectively, suggesting that organophilic character has developed on the surface after aminosilane treatment. The _s ^p value was almost similar after the treatment, probably because of the polar characteristics of amino groups.     

Application of centrifugal counter-current chromatography to the separation of macrolide antibiotic analogues. I. Selection of solvent systems based on solubility and partition coefficient investigations

As the first part of our studies on counter-current chromatography, the methodology for selecting suitable solvent systems was established based on detailed investigations of solubility and partition coefficients (log K) of macrolide antibiotic analogues. The solubility of two important macrolides, ascomycin and FK-506, was measured in a series of common solvents, where their polarities were ranked with dielectric constants. The partition coefficients of the two macrolides were compared in various binary, ternary, quaternary solvent systems. Hexane-tert.-butyl methyl ether-methanol-water system was selected based on suitable log K of solutes and hydrogen-bonding properties of solvents. In the further optimisation of composition proportions in the multicomponent solvent system, hexane-tert.-butyl methyl ether-methanol-water (1:3:6:5) showed the best solvent selectivity by giving the most prominent difference of partition coefficient (delta log K) between ascomycin and FK-506. With this solvent system, a baseline preparative separation of these two very closely related 23-membered macrolide antibiotics was successfully achieved by employing the newly introduced Quattro counter-current chromatograph.     

Group separation of trivalent actinides and lanthanides by tertiary pyridine-type anion-exchange resin embedded in silica beads

The separation of trivalent actinides and lanthanides was studied by using newly developed tertiary pyridine-type anion-exchange resin embedded in silica beads. Chromatographic elution experiments were carried out by using a packed column of the new resin and methanol-hydrochloric acid solution as an effluent. We confirmed that the actinides were eluted well from the elution bands of lanthanides. Actinides and lanthanides were eluted according to the reverse order of their atomic number.     

Study of a mathematical model of metal ion complexes in solvent sublation

Separation of metal ion complex, [(C(12)H(8)N(2))(3)Fe(2+)], with surfactant sodium dodecylphrate (DLS) complex from aqueous phase was carried out by solvent sublation, which obeys first-order kinetics. On the base of the complete transport mechanisms, the Langmuir adsorption, and the ion complex equilibrium in the aqueous phase, a mathematical model for the [(C(12)H(8)N(2))(3)Fe(2+)]-surfactant ion complex is obtained with the aid of the Mathematic 4.0 program, 4th Runge-Kutta method, and the Matlab programs. The effects of many parameters, such as K(a), K(l), K(ow), d(i), V(o), V(w), and Q(a), on solvent sublation are investigated. Furthermore, the simulation showed that the model is substantiated for experiments on the solvent sublation of the complex.     

Formulation design of ointment base suitable for healing of lesions in treatment of bedsores

We intended to develop a desired ointment base suitable for treatment of bedsores including the proliferation of granulation and epidermis. The main bedsore bacteria detected in our hospital were S. aureus in gram-positive coccus and P. aeruginosa in gram-negative bacillus. As the macrogol ointment (MO) was found to have bactericidal effects on these bacteria, MO was adopted as the base for the objective ointment. To improve the properties of the ointment base such as regulating the humidity of the exudation and controlling the release of antibiotics formulated in the ointment, co-formulating effects of various additives to MO were evaluated. The sustained release function of the ointment base was obtained by adding hydrophilic petrolatum (HP) to MO. However, the resultant ointment was found to have a poor humidity regulating property. On the other hand, MO containing 5% of hydroxypropyl cellulose (HPC) showed both the humidity regulating and the controlled drug releasing properties. It was considered that HPC particles dispersed in the ointment could be swelled by absorbing water to form a gel network. The curd tension meter tests for the ointments prepared with the various polymers showed that the MO-HPC base, which showed the highest sustained drug releasing property, was found to have the highest hardness. This result means that HPC formulated into the base forms the most rigid gel structure to resist the erosion of the ointment and to control the drug release.     

Stark and Zeeman spectroscopies of 4f 66s6p 7G1-6 levels in Sm I under external electric and magnetic fields

Systematic study of hyperfine structures, Zeeman and Stark effects in Sm I is performed for the lowest ⁷G_1-6 levels belonging to the configuration 4f ⁶6s6p by atomic-beam laser spectroscopy with fluorescence detection. The hyperfine coupling constants of ⁷G_2-6 levels are determined. From the Zeeman splittings for the 4f ⁶6s ^{2 7}F_2-6 ? 4f ⁶6s6p ⁷G_2-6 transitions, g-values are determined for the ⁷G_2.6 levels and the precision is improved by several orders of magnitude. From the Stark splittings for the ⁷F_0-3 ? ⁷G_1-3 transitions, tensor polarizabilities α ₂(J) are determined for the upper ⁷G_1-3 levels. Particularly for the ⁷G₁ level (15 650.55 cm^?1) which has close-lying opposite-parity level, the isotope dependence of α ₂(J) is clearly observed for the first time.     

Selection rules for Raman scattering from eigenmodes of spherical nanoparticles

The elastic vibrations of spherical nanoparticles have been widely studied by Raman scattering. However, there exist more than one set of selection rules for Raman scattering from these vibrations. For instance, Kanehisa has stated that only torsional modes with angular momentum l = 2 are Raman-active, while Tanaka et al. proposed that spheroidal modes of even l and torsional modes of odd l are Raman-active. These contradict selection rules of Duval which states that only spheroidal modes of l = 0 or 2 are Raman-active. Our present calculations based on a macroscopic model show that all torsional modes have vanishing intensity in the Raman spectrum.     

Structure-specificity relationship of cardiac glycosides as a substrate for glucohydrolase II

Cardenolide glucohydrolase II (CGH II) is a cardenolide-specific glucohydrolase obtained from Digitalis lanata leaves. We investigated the structure-specificity relationship of several cardenolide disaccharides as a substrate for CGH II. Conformation analysis of the substrates was performed using molecular mechanics calculations. The sugar chain conformation of two inert glycosides was significantly different from that of the other glycosides. The other two glycosides, which were weak substrates of CGH II, were suggested to have an intramolecular hydrogen bond between the sugar groups. It was deduced that this hydrogen bond restricts the conformational change of the sugar chain and prevents the glycosides from enzymatic recognition.