Takeru Fujii

A solid-in-oil nanodispersion for transcutaneous protein delivery.

Transcutaneous delivery attracts much attention but remains a challenging strategy for hydrophilic macromolecular drug administration. In the present study, we demonstrated that a solid-in-oil (S/O) nanodispersion, an oil-based nanodispersion of hydrophilic drugs, effectively enhanced the permeation of proteins into the skin. All of the different model proteins, FITC-labeled insulin (MW ca. 6 kDa), enhanced green fluorescent protein (EGFP, MW ca. 27 kDa) and horseradish peroxidase (HRP, MW ca. 40 kDa), permeated through the stratum corneum of Yucatan micropig skin in vitro by forming a S/O nanodispersion. The penetrated EGFP and HRP exhibited green fluorescence and catalytic activity, respectively, suggesting that these proteins can permeate into the skin in a functional form. The results indicated the potential utility of the S/O nanodispersion as a novel vehicle for transcutaneous protein delivery.

Enzyme leakage due to change of membrane permeability of primary cultured rat hepatocytes treated with various hepatotoxins and its prevention by glycyrrhizin

Various hepatotoxins were added to the medium of primary cultures of adult rat hepatocytes and the release of the cytosolic enzymes lactic dehydrogenase, glutamic-oxaloacetic and glutamic-pyruvic aminotransferases were measured 24 h later. CCl4 at low concentrations caused dose-dependent release of soluble enzymes into medium without appreciable cytolysis of the hepatocytes. Mitochondrial enzymes were not released under these conditions. At 5 mM CCl4, both soluble and mitochondrial glutamic-oxaloacetic aminotransferase were found in the culture medium. Glycyrrhizin, a triterpenoid glycoside of licorice roots, prevented the enzyme release caused by CCl4.

Reduction of Gastric Ulcerogenicity During Multiple Administration of Diclofenac Sodium by a Novel Solid-in-Oil Suspension

This article reports a significant reduction of gastric ulcerogenicity by complex formation of a nonsteroidal anti-inflammatory drug with surfactants. Diclofenac sodium (DFNa) was suspended in medium chain triglyceride (MCT) by forming a complex with an edible lipophilic surfactant. Two types of suspensions, prepared through a membrane emulsification with different pore sizes, were evaluated according to the degree of gastric damage following multiple oral administration in rats. It was shown that gastric ulcerogenicity of DFNa was reduced by the surfactant–drug complexes, at doses up to 12 mg/kg, whereas severe gastric damage was observed upon oral administration of the aqueous solution at doses of 6 mg/kg. Comparable blood levels of DFNa were observed after administration of solution and suspension formulations.

Role of liver‐type glucose transporter (GLUT2) in transport across the basolateral membrane in rat jejunum

To obtain information on the regulation of glucose transport across the basolateral membrane (BLM) of intestinal epithelial cells, we measured the number of [3H]cytochalasin B binding sites and the level of liver‐type glucose transporter (GLUT2) protein in the BLM in the jejunum of rats (i) with diabetes (ii) given a high‐carbohydrate diet or (iii) with experimental hyperglycemia (12 h infusion of a high‐glucose solution). A glucose uptake and the number of d‐glucose inhibitable [3H]cytochalasin B binding sites in BLM vesicles were significantly increased in all three conditions. Western blot analysis showed that the amount of GLUT2 protein in BLM vesicles was increased in rats with diabetes and those given a high‐carbohydrate diet, but not in those with experimental hyperglycemia. These results suggest that there is a mechanism for rapid regulation of glucose transport in the BLM that does not depend on change in the amount of GLUT2.

KIH-201: A New Enhancer of Chemiluminescence in the Luminol-Hydrogen Peroxide-Peroxidase System Characterized by A High-Performance Luminometer

Abstract We developed new phenolic enhancers of chemiluminescence in the luminol-hydrogen peroxide-horseradish peroxidase reaction. We designed, synthesized, and tested three series of phenolic enhancers as follows: 1) hydroxybenzylidene-cyclopentenediones (KIH-201, KIH-203, TX-1123, and TX-1124), 2) 4-hydroxybenzylidene-malononitriles (TX-825, TX-1121, TX-1122, TX-1840 and SF-6847), and 3) 2, 4-dichlorophenol derivative (TX-816). Luminescence measurements were performed with a new high-performance luminometer, which have a superior photon counting system (gate time: 10–100 ms) and an automatic injector (variable range: 10–190 μA). We found that the arylidene-cyclopentenedione KIH-201 [2-(4′-hydroxy-3′-methoxy-benzylidene)-4-cyclo-pentene -1,3-dione] was an effective enhancer similar to that of p-iodophenol, known as the most strong enhancer of this chemiluminescent system. This KIH-201 will facilitate the luminol - hydrogen peroxide - horseradish peroxidase reaction to be sensitive chemiluminescence.

Differential mechanisms of induction of ornithine decarboxylase in rat intestine by l- and d-amino acids

A single intragastric administration of glycine, L- and D-alanine, and L-and D-serine into rats resulted in a more than 20-fold stimulation of intestinal mucosal ornithine decarboxylase (ODC) within 4 h. The stimulation of ODC activity was accompanied by an increase in the amount of immunoreactive ODC protein. The induction of ODC by D-amino acids was in all likelihood attributable to an enhanced accumulation of ODC-specific mRNA species as revealed by Northern blot and dot-blot hybridization analyses. However, the induction by glycine and L-amino acids was not explainable by changes of mRNA since the changes in mRNA contents were only marginal. Since the turnover rates of L-serine-induced and D-serine-induced intestinal ODC protein were the same as the non-induced control, we concluded that the induction by glycine and L-amino acids was brought about by an increased efficiency of translation of the ODC message.

Ontogeny of DNA synthetic rhythms in chick (Gallus domesticus) liver

1. The diurnal pattern of DNA synthesis and mitotic activity in neonatal (1-4-day-old) chick liver were investigated under various feeding and lighting regimens. 2. In the meal-fed chicks under the condition of light-dark cycle, DNA synthesis exhibited a 12 hr cycle; the peaks occurring at 9:00 and 21:00. 3. Fasting caused a gradual decrease in the 21:00 peaks. 4. The changes in the lighting regimen to 24 hr continuous lighting also caused a profound change in the DNA-synthetic pattern, suggesting a complex interplay of feeding and lighting regimens in the manifestation of the DNA-synthetic rhythm in neonatal chick liver.