This review describes the conformations of nucleic acids and oligonucleotides containing cyclonucleoside residues. From the studies on the oligomers of cyclonucleosides, it was demonstrated that oligonucleotides having a high anti glycosidic conformation can make up a left-handed helical system in contrast to the right-handed helical system of natural nucleic acids. Other left-handed helical structures which have been recently discovered or proposed are also reviwed. It is concluded that the glycosidic conformation in the monomer unit of nucleic acids play an important role in determining the handedness of the helical structures.
A glow discharge of tetrafluoroethylene gas under reduced pressure was applied to solid substrates having complex surface structures to deposit a thin film of plasmapolymerized tetrafluoroethylene and the achievement of the resulting coating layers on the surfaces was investigated. Since the fluorocarbon polymer is known to be highly hydrophobic, 250-297μm grains of calcium pantothenate having significantly hygroscopic nature was plasma-coated to evaluate the coating effect by which moisture uptake of the material would be effectively prevented. It was observed, however, that considerable degree of moisture uptake was preserved though the thickness of the coating moderate film was 3500 Å. Therefore some imperfect spots in the coating layer and/or moisture transport through the polymer thin film were to be supposed. Another coating experiment with spherical particles of Porapak N having approximately the same diameter of the calcium pantothenate showed excellently uniform coating layer profiles by a microscopic observation of the sectional view of the particles. Other cases of the plasma coating with bulk material having sponge-like interior structure or compressed cellulose fiber block indicated some distribution of plasma-polymer from the surface towards certain depth of the materials, but the polymer steeply disappeared at the further interior. In consideration of various experiments, the plasma-coating of the calcium pantothenate was thought to be fairly perfect in contact with fresh plasma gas, but the polymer thin film was probably somewhat gas permeable for small molecules such as water vapor.
Some solid drugs containing water-soluble pharmaceuticals were coated by thin film of plasma-polymerized tetrafluoroethylene produced in a glow discharge of the monomer gas under reduced pressure and the possibility of slow release of the pharmaceuticals as a result of the plasma coating was investigated. Lysozyme chloride and nicotinic acid were chosen as model pharmaceuticals having large and small molecular sizes and the rates of dissolution from tablets, powders, and granules in aqueous medium were measured by light absorption of the aqueous solutions of the pharmaceuticals. It has been observed that the slow release of the pharmaceuticals from the solid drugs was fairly well controlled by changing film thickness of the plasma-polymer, while, in the case of powder drug, mixing of the material during the plasma process was essential to ensure homogeneous exposure of the entire powder material to the plasma gas. It has been also supposed that the lysozyme chloride having large molecular size was not permeable through the coating film but it was released through cracks produced by expan sion of the drugs after absorption of moisture through the coating film and/or imperfect spots of the coating film possibly located at deep cavities on the surfaces of the solid drugs, while the nicotinic acid having relatively small molecular size was released not only through the cracks and imperfect spots but also through the coating film by permeation.
A glow discharge of low-pressure pyridine vapor was applied to form a thin film of plasma-polymerized pyridine onto the surface of a porous membrane filter. The resulting composite membrane exhibited reverse osmosis characteristic for a dilute salt solution in which either degree of salt rejection and water permeability increased during the initial time of operation. Both degree of salt rejection and water permeability much more increased than in the neutral medium when the membrane was operated in acidic or alkaline salt solution. Further the change of reverse osmosis characteristic in acidic or alkaline medium was irreversible and at the same time the infrared spectroscopy found no change of chemical structure of the membrane after the treatment in acidic and alkaline solutions. Therefore a physical change such as enhanced extraction of smaller molecules involved in the plasma polymer to the acidic and alkaline media was thought as a reason for the change of reverse osmosis characteristic. Determinations of molecular weight distributions of the extract and the whole polymer supported the physical change. A hypothesis was therefore made that extraction of smaller molecules during the initial time of operation produced more micropores in the membrane having suitable pore size for reverse osmosis and that the extraction was significantly enhanced in acidic and alkaline salt solutions.
We have reinvestigated the alkaloidal constituents of the root of an Aconite species collected at Sado-island (Niigata Pref.). Four known compounds, i.e. hypaconitine, aconitine, mesaconitine, ignavine and a new base : sadosine were isolated and their structures were elucidated. The structure of sadosine was deduced to be 7-α-hydroxyignavine on the basis of the 1H- and 13C-nuclear magnetic resonance spectral data. Absolute configuration was determined by X-ray crystallography.
Lignans in the fruits of Schizandra (syn. Schisandra MICHX.) chinensis BAILL. (Schisandraceae) were quantitatively analysed by high performance liquid chromatography using a reversed-phase stationary phase. It was found that the commercially available samples considered to be collected in central and northern parts in Korea or China contained schizandrin (I), gomisin N (IX) and gomisin A (IV) as main components, while those in the samples collected in Japan were schizandrin (I) and deoxyscizandrin (VII). Seasonal variations of lignan contents in the fruits of S. chinensis collected in Nagano prefecture were also investigated. It became clear that all of the lignans were produced in the seed with its formation and that the contents gradually decreased in the same constituent ratio.
In order to characterize chemically bonded phases in high performance liquid chromatomatography analysis, the retention behaviors of fifteen steroids including estrogen, androgen, progestogen and corticoid were systematically examined by using ethyl acetate as a stronger component in an n-hexane-binary system. A linear relationship between the logarithm of the capacity ratio and that of the molar concentration of the binary solvent was confirmed for aminoand cyano-type bonded silica gel columns. On the basis of the retention indices of the bonded and non-bonded silica phases, the retentivity of the packing materials was determined as follows : amino-type is slightly stronger (1.1 times) and cyano-type weaker (0.6 times) than bare silica gel. The specific retentivity of an amino-column for polar steroids containing phenolic and alcoholic hydroxyl groups suggests a molecular interaction associated with hydrogen bonding between the polar packing surface and solute compounds. The selectivity of amino packing was found to be larger than cyano packing whose retention selectivity is similar to a bare silica gel.
As a continuation of our work on the characterization of chemically bonded phases by using ethyl acetate as a stronger solvent in an n-hexane-binary system, the retention behaviors of fifteen steroid hormones were systematically examined in an ethanolcontaining binary eluent. On the basis of a linear relationship between the logarithm of the capacity ratio and that of the solvent composition, the retentivities of amino, cyano and bare silica columns were determined. These columns all showed similar affinity, and stronger adsorption was observed for phenolic solutes while weaker adsorption was shown for acyl derivatives in the case of amino-type columns than that for other columns. The relative solvent strength of ethanol to ethyl acetate in n-hexanebinary solvents was confirmed by use of these three columns. The relative strength of ethanol to ethyl acetate increased especially in amino-type and bare silica columns.
Antitumor activity of culture filtrate substance (CFS ; MW≨13000) isolated from three strains (TA-3, H-81, and PB-1) of Vibrio anguillarum, a marine bacterium, against Ehrlich carcinoma cells in ddY mice was investigated. Sixty days after intraperitoneal (i.p.) inoculation of 1×105 tumor cells, groups of mice injected i.p. CFS (250μg/d/mouse×6 times) survived 20-80% and their mean survival was 40-55 d against the mean survival of 24 d in the control group. When 1×106 tumor cells were inoculated subcutaneously, CFS injected intraveously caused the inhibition of the tumor-growth. CFS of PB-1 strain exhibited markedly an adjuvant effect on antibody response in vivo against sheep erythrocytes. CFS of TA-3 strain was capable of increasing the incorporation of 3H-thymidine into in vitro cultured spleen cells of C57BL/6 mice, but both CFS of H-81 and PB-1 do not increase the incorporation.
Three derivatives of α-acyl-DL-A2pr-DL-A2pr-Thr-DL-A2pr-D-Leu-OH including 2, 3-diaminopropionic acid (A2pr) (a component of tuberactinomycin (Tum)) were synthesized to investigate the relationship between the chemical structure and antibacterial activity. These compounds were synthesized as pentapeptide by stepwise elongation method and by liquid phase method with dicyclohexylcarbodiimide and 1-hydroxybenzotriazole, and acylated by (+)-6-methyloctanoyl chloride or two kinds of aliphatic acyl chloride. It was proved that these compounds show very strong antibacterial activity against gram-negative bacteria. Each compound has about one fourth as strong activity as colistin sulfate has.
Application of high performance liquid chromatographic (HPLC) technique was attempted to the study of drug-protein interactions by immobilizing human serum albumin monomer (HSAm) to glyceryl porous blass beads (Glyceryl-CPG). Experiments were all performed at 4°C in 1/15 M phosphate buffer, pH 7.40, containing 0.01% ethylene diamine tetraacetic acid (EDTA) at a flow rate of 2 ml/min per column by both single and double column method. This flow rate was approximately ten times greater than that of the previous affinity chromatographic technique employing Sepharose 4B as a solid support. Thereby, effective time reduction in the determination of binding parameters was possible without apparent adverse effects of immobilization. Binding parameters were determined for the interactions with salicylic acid, warfarin, and diazepam. Diazepam, in particular, could not be previously studied with Sepharose 4B support due to its extensive binding to the support itself.
A rapid, simple, specific and quantitative assay for trapidil in the serum was developed by reversed-phase high-performance liquid chromatography. Only 20μl of the serum is required. Serum proteins are precipitated with 100μl of methanol. After the centrifugation, 90μl of the supernatant is injected into the chromatograph equipped with a Model U6K injector, a 3.9 mm×30 cm μBondapak C18 column, a Model M-45 Solvent Delivery System (Waters Assoc. Inc., ) and a Model S-310A ultraviolet detector (Soma optics Co., Ltd.) set at 0.01 AUFS (307 nm). The flow rate of the mobile phase of 28% acetonitrile solution containing 0.01 M sodium acetate (pH 7.0) is 1.0 ml/min. The retention time for trapidil is about 13 min. The amount of trapidil is determined by measuring its peak height. Within-run and day-to-day reproducibilities for 1.0μg/ml are ±0.01 (±S.D. : n=10) and ±0.02 (n=10), respectively and those for 4.0μg/ml are ±0.03 (n=10) and ±0.11 (n=10), respectively. The recovery of added trapidil is 95.3-102%. The limit of detection is 0.5μg/ml of serum. The proposed method can be completed in less than 15 min. Pharmacokinetics of trapidil was studied on asthmatic patients. Trapidil was administered at a dose of 1.32-2.33 mg/kg by a constantrate intravenous infusion for 30 min. The level of trapidil in the serum was analyzed by using a one-compartment open model. The mean elimination rate constant (Ke) was 0.476±0.198 h-1, biological half-life (t1/2) was 1.72±0.768 h, K0/V was 6.20±4.13 (μg/ml)·h-1, D/V was 3.10±2.06μg/ml, Css was 18.9±19.3μg/ml, volume of distribution (V) was 0.826±0.426 l/kg, AUC240 min0 was 6.85±5.89 (μg/ml)·h, AUC∞240 min was 3.14±3.98 (μg/ml)·h, and total AUC was 10.0±8.83 (μg/ml)·h. All average data are given as mean±S.D. These data would be useful for determining precise dosage requirement for trapidil in asthma.
In order to obtain an experimental inflammatory model for the evaluation of various antiphlogistics, λ-carrageenin was employed and the results of the histological changes in rats injected 1% λ-carrageenin into the pleural cavity were mainly reported. In addition, for the purpose of elucidating the damage to the gastric mucosa, an experimental gastric erosion was brought about in the rats by the oral administration of 100 mg/kg of aspirin, 3% acetic acid, 1% λ-carrageenin, and an injection of 1% λ-carrageenin into the pleural cavity. The stomach of these rats in an artificial gastric juice was incubated. The rats injected with λ-carrageenin decreased remarkably in body weight, and in the weight of their lungs, heart and thymus. However, the liver increased in weight. Fibrin clots were histologically found on the pleural surface at the injected side, along with significant congestion associated with neutrophils and lymphocytes infiltration in the liver and spleen. The results concerning the measurement of tyrosine suggested undoubtable damage to the mucosa of stomach administered λ-carrageenin. Thus, this model is useful for estimating the various antiphlogistic efficacies.
In order to examine drug effects on an extrapyramidal symptom the muscular rigidity produced by morphine was evaluated by an electromyographic method in the gastrocnemius muscle of rats and the result was compared with that by a catalepsy method. Morphine hydrochloride at a dose of 2.5 mg/kg s.c. produced a significant increase in electromyogram activity. An administration of morphine hydrochloride at doses of 10, 20 and 40μg into the spinal subarachnoidal space or cerebral ventricle also produced a marked increase in electromyogram activity. These effects of morphine were antagonized by naloxone permoate at doses of 0.5 to 2 mg/kg i.p. When morphine rigidity was estimated by the catalepsy method, the identification limit of the dose was more than 5 mg/kg s.c. The increase in electromyogram activity after morphine hydrochloride 2.5 mg/kg s.c. was suppressed by centrally-acting muscle relaxants, mephenesin, baclofen and carisoprodol. It was also inhibited significantly by dopaminergic agonists, apomorphine and L-dopa. These results suggest that an electromyographic analysis in the gastrocnemius muscle of lightly-restrained unanesthetized rats is a sensitive method to detect quantitatively the rigidity produced by morphine and to evaluate drug effects on it.
The trace amount of by-products co-existing with a large amount of thin layer chromatography (TLC) untreated benz [c] acridines (BAc) were defined by using TLC, high performance liquid chromatography (HPLC), gas chromatography (GC) and GC-mass spectrometry (GC-MS). Twelve BAc were separated by TLC on a silica gel 60 GF254. TLC-treated BAc showed one spot on TLC and were determined by HSLC, GC and GC-MS. This method using TLC for purifying BAc suggested to be very useful and simple.
High performance liquid chromatographic (HPLC) method for the detection of doping drugs from the horse urine containing polyethylene glycol (PEG) was developed. Five milliliter of the horse urine was absorbed on a Sep-Pak C18 cartridge, followed by elution with 2 ml of CHCl3. After evaporation of the solvent, the obtained residue was dissolved in a mixture of CH3OH-H2O (7 : 3, v/v), injected onto a HPLC column packed with a Shodex D-814 stationary phase eluted at 40°C with a mixture of CH3OH-H2O (7 : 3, v/v) and detected with ultraviolet detector and differential refractometer. Ten kinds of doping drugs could be separated within 40 min without interference with PEG.