Shin-ichiro Tanioka

Effects of chitin and chitosan particles on BALB/c mice by oral and parenteral administration

Chitin and chitosan were administered orally and parenterally into mice and their toxicity was investigated. When 5 mg of chitin were injected intraperitoneally every 2 weeks over a 12-week period, the mice were apparently normal, but histologically, many macrophages with hyperplasia were observed in the mesenterium and foreign-body giant-cell-type polykaryocytes were observed in the spleen. The polykaryocytes were also observed in the spleen of the mice injected subcutaneously with 5 mg of chitin, but no other changes were observed. When 5 mg of chitosan were injected intraperitoneally, the body weights of the mice decreased significantly and inactivity was observed in the fifth week. Histologically, many macrophages with hyperplasia were observed in the mesenterium. Subcutaneous injection of 5 mg of chitosan did not evoke the general and cellular abnormalities. Oral administration of 5% chitosan via a casein diet caused mouse body weights to decrease and also decreased the number of Bifidobacterium and Lactobacillus in normal flora of the intestinal tract. These results indicate that special care should be taken in the clinical use of chitin and chitosan over a long time period.

Influence of physico-chemical properties of chitin and chitosan on complement activation

Abstract To recognize the complement activation by chitin and chitosan, various physico-chemical aspects were studied. Complement activation was determined by change of plasma C3 concentration using single radial immunodiffusion method. Results were as follows: in samples with homogeneous acetylation (oDAC), C3 concentration was decreased with the increase in the degree of acetylation of oDAC. In oDACs 50 and 42 (water soluble materials), however, C3 was not decreased. In samples with heterogeneous acetylation or deacetylation samples (eDAC), all samples showed C3 activation even in eDAC 53 (solid material) and have almost same activity on complement activation. C3 activation was not seen in low molecular weight materials including d -glucosamine. The important factors inducing complement activation by chitosan-based mucopolysaccharide should be solids. The samples with heterogeneous acetylation (eDACs) had a stable ability on complement activation than with homogeneous acetylation (oDACs).

Systemic effect of chitin after intravenous administration to dogs

Abstract The systemic effect of chitin and chitin oligomer after intravenous administration was investigated in dogs by determining the chemiluminescence (CL) response and the white blood cell count (WBC). Chitin oligomer (2mg/kg) and physiological saline (5ml) did not have a systemic effect. However, in the dogs injected with chitin, WBC decreased significantly from 1 to 4 h after injection and then increased gradually to 1.4 times the pre-injection level at 72 h, while CL was significantly increased 1–2 h after injection.

The Favored Formation of Threo-3-Pentulose in the Formose Reaction

ABSTRACT The “formose reaction” is the generic name for the base-catalyzed condensation of formaldehyde to give “formose” which is a complex mixture of sugars, alditols, organic acids, etc.2 Increasing attention has been recently given to this reaction because of its possible importance in the manufacture of edible carbohydrates from a simple material and its possible role in the prebiotic synthesis of carbohydrates.3 In our recent study4 on the reaction catalyzed by triethylamine (TEA) and thiamine HCl in N,N-dimethylformamide (DMF)-water mixed solvent, the formation of 3-pentulose (GP-11-1 corresponding to GLC peak number 11-1) was suggested. P. Decker et al.5 also reported that at the end of formaldehyde consumption the concentration of 3-pentuloses became smaller because of their higher reactivity (these carbohydrates cannot form stable furanoses or pyranoses) compared to tetroses, pentoses, and hexoses. Although the isolation of 3-pentuloses was not described in that report,5 erythro-3-pentulose and ...