Targeting of sebocytes by aminolevulinic acid-dependent photosensitization

Photodynamic therapy using 5-aminolevulinic acid-induced protoporphyrin IX has been developed as a very useful therapeutic modality. Recently, several authors have reported on the efficacy of this procedure for acne. This approach is based on the fact that 5-aminolevulinic acid-induced protoporphyrin IX has strong selectivity for sebaceous glands. We used the immortalized human sebaceous gland cell line SZ95 to investigate cellular mechanisms of photodynamic therapy using 5-aminolevulinic acid-induced protoporphyrin IX. Quantification of induced protoporphyrin IX production showed dependence on the applied 5-aminolevulinic acid dose. When SZ95 sebocytes were differentiated by arachidonic acid treatment, there was no difference between them and the control cells with respect to both the amount of 5-aminolevulinic acid-induced protoporphyrin IX and the phototoxic effects. We altered protoporphyrin IX formation rates by growing cells scattered as single cells in the culture dishes. Single cells produced significantly lower protoporphyrin IX levels than those grown with intercellular contacts. Intracellular localization of protoporphyrin IX was imaged using confocal laser scanning microscopy. The differentiation-specific lipid droplets were virtually excluded from protoporphyrin IX fluorescence. In addition to weak mitochondrial and strong membrane fluorescence, distinctive spots with strong fluorescence were observed. These did not colocalize with fluorescent probes for mitochondria, lysosomes or the Golgi apparati.     

An application of Bayesian (ABIC) smoothing methods to estimating space and time variations in the magnitude distributions of earthquakes

On the basis of Akaike's Bayesian information criterion (ABIC), a new method of estimating temporal and spacial variations in the magnitude-frequency relation (b value) is developed. The space-time volume studied is divided into a number of segments having equal volume, for which b values are estimated. The smoothness of the estimated b value is guaranteed by the introduction of a prior distribution. The parameters of the prior distribution are chosen in such a way as to minimize the ABIC. This method is employed to study the temporal and spatial variations of b values for microearthquake activity in the Kanto, Tokai and Tottori areas, where seven earthquakes having magnitudes of M6.0 and larger have recently taken place. States of temporal variations of b values are classified into three groups; increase, decrease and nochange. The space-time volume of decrease accounts for approximately 10% of the total volume. For a period before the occurrence of earthquakes, the decrease appears more frequently than might be expected. It is concluded that the decrease in the b value is a promising candidate to act as a precursory phenomena.This work was carried out under the ISM Cooperative Research Program (88-ISM CRP-60).     

Photophysics and photochemical dynamics of chlorotoluene molecule

Laser-induced fluorescence spectra of jet-cooled chlorotoluene molecules are reported for the S₁ state. The fluorescence excitation spectrum of m-chlorotoluene shows some low-frequency bands up to 200 cm⁻¹ above the S₁ origin, which are assigned to internal rotational modes of the methyl group. Beyond 300 cm⁻¹ and up to approximately 1500 cm⁻¹ sharp vibrational bands are observed, which are assigned by measurement of the dispersed fluorescence spectrum on excitation of each vibrational band. The vibrational energies of the C---Cl stretching modes for the o-, m- and p-chlorotoluene molecules are 341, 378 and 360 cm⁻¹ respectively in the S₁ state.     

Application of Pentafluorobenzyl and Hexafluoroisopropyl Esters for Retention Indexes in GC-Negative Ion Chemical Ionization MS

In order to use the linear temperature programmed retention index (LTRI) for the negative ion chemical ionization (NCI) mode in which n-alkanes cannot be detected, LTRIs were newly defined using homologous series of pentafluorobenzyl and hexafluoroisopropyl esters. The method for converting LTRI based on n-alkanes to the new LTRIs was also developed and applied to PCB and chlorinated pesticide analysis. The results demonstrated that the LTRI databases, which were developed based on n-alkanes, could be utilized for NCI analysis.     

Re-examination of the Reactivity of N-Carboxy Amino Acid Anhydrides 1. Polymerisation of Amino Acid NCAs in Acetonitrile and in the Solid State in Hexane

Ring-opening polymerisation of N-carboxy anhydrides of γ-benzyl-L- glutamate, L-alanine and L-leucine by a primary amine initiator in acetonitrile and in hexane was examined, with care taken to avoid contamination by moisture. The polymerisation of amino acid NCAs initiated by butylamine in hexane proceeded in the crystalline state (solid state) because the NCA crystals did not dissolve in hexane. Although amino acid NCAs were believed to polymerise completely in acetonitrile, polymerisation of the amino acid NCAs in acetonitrile was found to stop at around 20% conversion. As resulting polypeptides did not dissolve in acetonitrile, the polymer terminals were considered to be occluded in the polymer precipitate. On the other hand, each amino acid NCA was much more reactive in the solid state in hexane than in acetonitrile. Especially, L-leucine NCA showed remarkable reactivity in the solid state. The reactivity in the solid state was explained with reference to the crystal structure.     

Capillary electrophoretic separation of humic substances using hydroxyethyl cellulose as a buffer additive and its application to characterization of humic substances in a river water sample

We have developed a concise tool for the investigation of the transition of humic substances in environmental water. The separation of water-soluble humic substances was achieved rapidly and effectively by capillary electrophoresis using a polyacrylamide-coated capillary and a phosphate electrophoretic buffer solution (pH 7.0) containing hydroxyethyl cellulose. The separation mechanism was assessed using the ultrafiltration technique. The effect of the complexation of humic substances with metal ions was studied by using the proposed method. When Fe(III) ions or EDTA was added to the sample solution of fulvic acid, a distinct change in the electropherogram pattern based on the conformational change of fulvic acid was observed. The successful application of the proposed method to the characterization of humic substances in a river water sample was also demonstrated. Figure Addition of Fe(III) ions or EDTA to a solution containing fulvic acid (FA) results in a distinct change in the electropherogram pattern, which reflects the conformational change of FA: this forms the basis for the characterization of humic substances in river water samples