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Biomedical subjects

M Shimuzu

Publications and source records attributed to M Shimuzu.

4 recordsLinked to original sources
PubMed1999

Permeation of hesperidin glycosides across Caco-2 cell monolayers via the paracellular pathway.

The intestinal permeability to hesperidin glycosides was investigated by using a cultured monolayer of Caco-2 as a model for the small intestinal epithelium. Hesperidin glycosides were added to the apical side of the monolayer, and the substances that permeated to the basolateral side were determined by HPLC. Whereas hesperidin did not permeate across the Caco-2 monolayer, probably owing to its low solubility, the hesperidin glycosides did permeate. The transepithelial transport of hesperidin glycosides occurred in time- and dose-dependent manners. The transport was observed to be energy-independent, and was inversely correlated with the transepithelial electrical resistance (TEER) of the monolayer. These results suggest that hesperidin glycosides permeate across the Caco-2 cell monolayer via the paracellular pathway.

Caco-2 Cells↗
PubMed1990

Properties of phosphorylated 32 kd nonamelogenin proteins isolated from porcine secretory enamel.

Enamel proteins were isolated from specific locations of permanent porcine incisors at various developmental stages, namely, the outer (young) and inner (old) secretory, and maturing (chalk-like in appearance) enamel. The selective adsorption of these matrix proteins onto hydroxyapatite (HA) crystals was investigated in the presence of dissociative agents. The results showed that the proteins with the highest adsorption affinity were present at the highest concentration in the vicinity of the ameloblasts, i.e., in the outer enamel layer; a substantial reduction of these proteins was observed in the older (inner) secretory enamel and in the tissue in the maturing stage. An interesting finding was that a group of proteins having molecular masses of 32 kd present only in the inner secretory enamel, adsorbed strongly onto the HA crystals and were potent inhibitors of HA crystal growth. This 32 kd group contains phosphorylated glycoproteins; they are rich in Pro, Glu, Gly, and Asp and the N-terminal sequence was LXQVPGRIPPGYGRPPTP-, having no resemblance to the reported sequences of amelogenins. It was also found that the 32 kd moieties remained only as trace constituents in the maturing enamel, suggesting that most of them were removed as soluble constituents in the tissue fluid or further degraded by enzymatic activity during the late secretory stage. The results obtained support the view that amelogenetic mineralization is regulated by the presence of various organic matter and, importantly, that their efficacy as inhibitors of mineralization may be modulated through their degradation.

Amelogenesis↗
PubMed1989

Relationship between hepatic glutathione content and carbon tetrachloride-induced hepatotoxicity in vivo.

The relationship between carbon tetrachloride (CCl4)-induced hepatotoxicity and hepatic glutathione (GSH) content was investigated in fed and fasted rats. The elevation of serum glutamic-pyruvic transaminase (GTP) activity by CCl4 treatment was enhanced by fasting. Although the hepatic GSH content fo 12-hour-fasted rats was higher than that of fed rats determined at 6 p.m., the serum GPT activity of the former was higher than that of the latter. Starvation had no effect on the activities of hepatic glutathione peroxidase (GSH-Px) and glutathione reductase (GR). The results suggest that the potentiation of hepatic injury by CCl4 cannot be related to hepatic GSH content.

Alanine Transaminase↗