Publications by authors named "Koichi Isowa"

Glucagon-like peptide-1 (GLP-1) is an incretin hormone that regulates the insulin secretion depending on blood glucose level. Recent studies show that the unsaturated fatty acids can promote GLP-1 secretion from intestinal L-cells. We have shown previously that docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) administered into a mouse closed intestinal loop, especially into the colonic segment, stimulate GLP-1 and insulin secretion and have a hypoglycemic effect, suggesting that DHA and EPA have potential as antidiabetic agents.

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Transdermal delivery of drugs has gained attention as an alternative to intravenous and oral methods of delivery. However, the skin permeation of drugs is generally poor. To overcome this problem, many permeation enhancers have been developed.

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Penetratin, a 16-residue peptide, is used widely as a highly efficient delivery carrier for a wide range of poorly permeable therapeutic cargoes. The crucial structural features of penetratin remain unclear, as demonstrated by the difficulties encountered in designing new molecules. The efficiency in enhancing nasal insulin absorption was compared between l-penetratin and 20 of its analogues in rats.

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The goal of this study was to evaluate whether cell-penetrating peptides (CPPs) affect the nasal absorption of insulin. L- or D-forms of penetratin, or the L- or D-forms of octaarginine (L- or D-R8), was used as first time for nasal insulin delivery. Furthermore, the concentration of lactate dehydrogenase (LDH) in nasal lavage fluid was determined and a histopathological study of nasal respiratory epithelium was conducted.

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Photocrosslinked polyacrylic acid hydrogel, made from polyacrylic acid (PAA) modified with 2-hydroxyethyl methacrylate (HEMA), is a promising candidate adhesive for dermatological patches. In this study, we investigated the further availability of hydrogel as an adhesive for dermatological patches using a hydrogel containing indomethacin (IDM) as a model anti-inflammatory patch. From an orthogonal experimental study, we clarified the relationships between formulation factors and characteristics of model formulation.

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The effect of iontophoresis and switching iontophoresis on the skin accumulation of drugs was investigated. An acrylic diffusion cell mounted with electrode cells (bore: 2.2 cm) with circular platinum electrodes (diameter: 2.

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Kumazasa extract (KE) and its whole solid component (EXT)-containing chitosan films produced by drying in air and lyophilization, abbreviated to ND and FD films, respectively, were examined for efficacy and healing features using a deep skin ulcer model in rats. Their effects were compared with those of clinically available dosage forms, Beschitin W, Geben cream and U-PASTA. KE alone exhibited a better effect as compared with other preparations, and FD films also more effective than control in the early stage.

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The aim of this study was to evaluate whether oligoarginine, a cell-penetrating peptide (CPP), can improve intestinal absorption of insulin in rats. Peptides composed of six (R(6)), eight (R(8)) and 10 (R(10)) residues of arginine were used as the CPP. No insulin absorption was observed following administration of insulin solution alone; however, insulin absorption increased dramatically after coadministration of the D-form of R(6) (D-R(6)) and the L-form of R(6) (L-R(6)) in a dose-dependent manner.

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A case of spontaneous malignant lymphoma in a Japanese macaque (Macaca fuscata) was pathologically, etiologically and virologically studied. Nasal cavity was involved in the neoplastic lesions in addition to lymphoid and visceral tissues. Histopathological analyses revealed the presence of neoplastic cells classified into histiocytic Hodgkin-like cells and Reed-Sternberg-like cells.

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The significant inhibitory action of diclofenac formulated in mixed micelles of lecithin with cholate or deoxycholate was observed on the rat hind paw edema induced by carrageenan. In the primary stage, mixed micelle formulation of deoxycholate was more effective compared with that of cholate. However, in the final term, the inhibitory action was similar in both formulations.

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