Effect of TRX-liposomes size on their prolonged circulation in rats

Newly formulated cationic liposomes (TRX-liposomes) with four different mean diameters were injected into twelve male rats via the lateral tail vein in order to evaluate the effect of liposomal size on pharmacokinetic parameters. TRX-liposomes disappeared from the blood according to the one-compartment model and demonstrated maximum and minimum half-lives of ca. 14 h (mean diameter of 114.3 nm) and ca. 5 h (mean diameter of 285.9 nm), respectively. This prolonged half-life tended to decrease at the boundary of 114.3 nm mean diameter. The optimal size (114.3 nm) for prolonged circulation of TRX-liposomes was consistent with that of pegylated liposomes such as Doxil((R)), however, the half-life was different among these liposomes. The electric charge of the TRX-liposomal surface is assumed to be responsible for this difference. The results of the present study will be very useful in the design of long-circulating cationic liposomes.     

Finding of remarkable synergistic effect on the aroxyl-radical-scavenging rates under the coexistence of α-tocopherol and catechins

Measurements of aroxyl radical (ArO^•)-scavenging rate constants () of antioxidants (AOHs) (α-tocopherol (α-TocH) and three catechins (CatHs) (ie, epicatechin (EC), epigallocatechin (EGC), and epigallocatechin gallate (EGCG)) were performed in ethanol solution, using stopped-flow spectrophotometry. values were measured not only for each AOH, but also for the mixtures of two AOHs (α-TocH and CatH). A notable synergistic effect that the value of α-TocH increases 1.29, 1.84, and 1.65 times under the coexistence of constant concentrations of EC, EGC, and EGCG, respectively, was observed for the solutions including α-TocH and CatH. Similarly, values of CatHs (EC, EGC, and EGCG) increased 1.72, 2.25, and 2.34 times under the coexistence of constant concentrations of α-TocH, respectively. UV-Vis absorption of α-tocopheroxyl radical (α-Toc^•) (λ_max = 428 nm), which had been produced by reaction of α-TocH with ArO^•, decreased remarkably under the coexistence of α-TocH and CatHs due to the fast α-TocH-regeneration reaction by CatHs. The result suggests that the prooxidant reaction due to α-Toc^• is suppressed by the coexistence of CatHs. By analyzing the formation and decay curves of α-Toc^•, it has been ascertained that one molecule of EGCG having three OH groups at B-ring may rapidly regenerate three molecules of α-Toc^• to α-TocH.     

Three bits eight states photochromic recording and nondestructive readout by using IR light

A photochromic polymer film containing three different diarylethene derivatives, that is, 1,2-bis(3,5-dimethyl-2-thienyl)perfluorocyclopentene (1), 1,2-bis(2,5-dimethyl-3-thienyl)perfluorocyclopentene (2), and 1,2-bis(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene (3) was prepared. Upon UV irradiation, the three derivatives changed to their closed-ring isomers having different colors, yellow, red, and blue. They showed different spectra not only in UV/Vis region but also in the IR spectral region. Upon irradiation with visible light of appropriate wavelengths, each closed-ring isomer was selectively bleached, and three bits eight states recording was performed. The eight states could be read out nondestructively by using IR light of appropriate wavenumbers.     

2,6-Diphenylbenzo[1,2-b:4,5-b']dichalcogenophenes: a new class of high-performance semiconductors for organic field-effect transistors

2,6-Diphenylbenzo[1,2-b:4,5-b']dichalcogenophenes including thiophene, selenophene, and tellurophene analogues as organic semiconductors for field-effect transistors were effectively synthesized in three steps from commercially available 1,4-dibromobenzene. All three benzodichalcogenophenes acted as good p-type semiconductors, and particularly the selenophene analogue, 2,6-diphenylbenzo[1,2-b:4,5-b']diselenophene, showed high FET mobility of 0.17 cm2 V-1 s-1.     

Analysis of conjugated linoleic acids as 9-anthrylmethyl esters by reversed-phase high-performance liquid chromatography with fluorescence detection

A simple and highly sensitive method for determining the fatty acid composition of food lipids containing conjugated linoleic acid (CLA) is described. The method is based on the separation of the 9-anthrylmethyl ester derivatives of saturated and unsaturated (conjugated and non-conjugated) fatty acids by reversed-phase high-performance liquid chromatography with fluorescence detection. Just like the other fatty acids, CLA reacts readily with 9-anthryldiazomethane at room temperature to produce 9-anthrylmethyl esters without isomerization and decomposition of the conjugated double bonds. Clear resolution of the individual fatty acids as their 9-anthrylmethyl esters is achieved on a highly efficient octadecylsilylated silica column (150- x 3-mm i.d., 3-microm particle size) using a stepwise gradient elution with methanol-water. The method is standardized with commercially available CLA isomers (cis-9, trans-11 and trans-10, cis-12-octadecadienoic acids, and their cis,cis and trans,trans isomers) and applied for determination of the fatty acid compositions of milk and sdairy products.     

Ozonolysis of five-membered heterocycles

The relative reaction rate of five-membered heterocycles with ozone was evaluated. These relative rates were correlated to the highest bond order value in the corresponding ring, calculated by the convenient HMO method. From this correlation, the reactivity of heterocycles with ozone was able to be predicted. Also it was concluded that the predominant product in the ozonolysis of five-membered heterocycles containing an oxygen atom was the corresponding carboxylic acid, while nitrogen heterocycles gave the corresponding amide.     

Effect of boron non-stoichiometry on B-site in perovskite type structure ScBxRh3 and CeBxRh3 on charges of atoms on A-site: study by X-ray photoelectron and nuclear magnetic resonance spectroscopies

The solid solutions of ScBRh₃-ScRh₃ and CeBRh₃-CeRh₃ are synthesized by the arc melting method, where RBRh₃ and RRh₃ (R=rare earth element) have perovskite and AuCu₃ type structures, respectively. The binding energy of Sc 2p_3/2 for ScB_xRh₃ increases with the boron concentration. The Knight shift of ⁴⁵Sc observed by nuclear magnetic resonance spectroscopy decreases with increase of boron concentration. The decrement of the Knight shift corresponds the Sc 4s electron density at the Fermi level. The intensity ratio of f²: f¹: f⁰ of Ce 3d XPS spectrum changes with boron concentration of CeB_xRh₃. It is concluded that in both cases of ScB_xRh₃ and CeB_xRh₃ the charge on the atoms on A-site changes with the concentration of the atoms on B-site, where the atoms are not directly bound.     

Determination of magnesium and calcium ions in seawater by capillary zone electrophoresis

Capillary zone electrophoresis is proposed for the determination of magnesium and calcium ions in seawater. A carrier solution containing EDTA was adopted for the complexation of these ions and the effect of sodium chloride concentration in the sample solutions on the results was examined. It was found that magnesium and calcium ions could be determined without any pretreatment by injecting 100-fold diluted seawater samples. Linear calibration graphs were obtained for standard solutions containing up to 10.0 mg/l of calcium ion when both peak area and peak height were used. On the other hand, a linear calibration graph was obtained for standard solutions containing up to 20.0 mg/l of magnesium ion when the peak area was used, while a curved one was obtained when the peak height was used. Relative standard deviations were 0.8 and 1.2% when a standard solution containing 5.0 mg/l of magnesium and 8.0 mg/l of calcium ions was analysed 8 times using the peak area. Limits of detection for magnesium and calcium ions were 0.13 and 0.26 mg/l, respectively. The proposed method was applied to the determination of magnesium and calcium ions in surface and bottom seawater samples.     

Synthesis,stability, and spectroscopic and electronic properties of three benzocyclohepta[alpha]azulenylium ions

Novel pi-systems, three benzocyclohepta[alpha]azulenylium ions, 7a-c, are synthesized, and their stability and properties have been characterized in terms of the position of the benzo-annulation and compared with those of the parent cyclohepta[alpha]azulenylium ion 4. Benzocyclohepta[6,7-alpha]azulenylium ion (7a) (p K R+ = 7.3, E red = -0.567 V vs Ag/Ag+) and benzocyclohepta[6,5-alpha]azulenylium ion (7b) (p K R+ = 5.1, E red = -0.482 V vs Ag/Ag+), which are annulated with benzene on the position having a high bond order of 4, are not appreciably destabilized compared with cyclohepta[alpha]azulenylium ion (4) (p K R+ = 7.3, E red = -0.458 V vs Ag/Ag+). On the other hand, benzocyclohepta[7,6-alpha]azulenylium ion (7c) (p K R+ = 1.6, Ered = -0.197 V vs Ag/Ag+) is considerably destabilized, probably due to enhanced contribution of the quinoid structure of the benzene ring, which is annulated on the position having a low bond order of the cyclohepta[alpha]azulenylium ion moiety. Furthermore, the cations 7a and 7b are more stable than 12,13-dihydrobenzocyclohepta[7,6-alpha]azulenylium ion (25) (p K R+ = 4.8, E red = -0.513 V vs Ag/Ag+), which is a dihydrogenated compound of 7a, while 7c is less stable than 25. These features are reflected in the considerable red shift of the longest absorption maximum of the electronic spectrum of 7c, as compared with those of 4, 7a, and 7b, and in the chemical shifts of the protons and their coupling constants of the (1)H NMR spectra. Furthermore, the (1)H NMR spectra and electronic spectra of 5H-benzocyclohepta[6,7-alpha]azulen-5-one (8a) and 7H-benzocyclohepta[6,5-alpha]azulen-7-one (8b) in acidic media have also been studied to clarify the spectral characteristics similar to those of 7a and 7b.     

Electrochemical analysis of single nucleotide polymorphisms of p53 gene

Single nucleotide polymorphisms (SNPs) of cancer repression gene p53 were analyzed electrochemically with ferrocenyl naphthalene diimide (1) as a hybridization indicator. The SNPs studied were the transition to A from G in the codon for amino acid at positions 175, 248 or 273 and the transversion to C from G in the codon for the amino acid at position 72. Thus, 20-meric oligonucleotides carrying the SNP site were used both as a sample and a probe with the latter immobilized on an electrode. Even one base difference on the p53 gene resulted in a significant difference in the current response of 1 and the magnitude of the response correlated with the amount of the DNA hybrid on the electrode. Moreover, when PCR products of exon 4, on which the P72/R72 SNP resides, of the p53 gene were analyzed by this method, the heterozygote and homozygotes were discriminated with modest precision.