Pepleomycin (PEP), 3-[(S)-l'-phenylethylamino]propylaminobleomycinhas potent activity and is less pulmonary toxic than bleomycin (BLM). Biological activity and toxicity of the following degradation products of PEP have been studied in detail: the product of carbamoyl migration (ISO), the product of decarbamylation (DC), the product of ring closure of the side chain on the pyrimidine moiety (RC), the depyruvamide product (DP) and the product of an er zymatic inactivation (DA).These degradation products showed much lower activity than PEP it: vitro: antimicrobial and anti-HeLa activities, inhibition of DNA synthesis in AH66 cells and the DNA strand cleavage. Acute toxicity and pulmonary toxicity were tested in mice. Results indicated much lower acute toxicity corresponding to the decreased in vitro activity when compared to PEP. DP and RC did not cause lung fibrosis in mice, while ISO and DC showed 1/2.6 and 1/5.7 degree of pulmonary toxicity, respectively, in comparison with PEP. Pepleomycin (PEP: 3-[(S)-I'-phenylethylamino]propylaminobleomycin)"has been developed as a novel aialog of bleomycin (BLM) which has less pulmonary toxicity than BLM mixture clinically in use tocay in the treatment of cancer.Although PEP is very stable at room temperatures, several degradation products were detected in its heated aqueous solutions of about pH 6. They were confirmed to be due to the carbamoyl migration-) (ISO), decarbamylation'' (DC), depyruvamide formation') (DP) and ring closure of the side chain on the pyrimidine moiety',") (RC). BLM is inactivated to the deamido compound (DA) by BLM hydrolases'. Since there are no systematic informations of biological and toxicological properties of the degraded BLM, such studies seem to be important from the drug-safety aspect.Studies on the action mechanism of BLM have revealed the complex formation between BLM and Fe (II) fo lowed by the coordination of oxygen to it in the action of BLM against DNA 7,8). The most probable structure of the complex has been proposed on the basis of the structure of BLMS). The a-amino and the secondary /3-amino groups of the /J-aminoalanine moiety (V), the pyrimidine ring N-I, the imidazole ring N of the /3-hydroxyhistidine moiety (IV) and the amino group of IV are involved in the complex formation to produce a square pyramidal coordination.The first group occupies the apical position. The carbamoyl group has been suggested to be in the vacant 6th coordination site. The a-amino group of V is absent in DP and blocked and restrained by the intramolecular amide bonding in RC. The carbamoyl group is absent in DC, and that in ISO is not involved in coordination. In DA, the free carboxyl group of V may be involved in coordination instead of the a-amino group. All these degradation products have a weaker ability in the complex

The variation in the longitudinal and radial direction of the R/T ratio and area ratio of vascular bundles, which are cross-sectional image features of bamboo, and the relationships between the R/T ratio or area ratio and relaxation behavior were investigated. These image features varied characteristically in the longitudinal and radial direction. Relationships between these image features and relaxation behavior was evaluated using the instantaneous creep compliance ln[J (0)] and the creep intensity ln [J(3 ×10 4)-J (0)]. Although both instantaneous compliance and creep intensity decreased as density increased, their dependence properties were remarkably different. Instantaneous compliance was strongly correlated with R/T ratio and density, which was related to the area ratio, whereas creep intensity was weakly correlated with density in a given range. The results indicate a difference between the two relaxation properties, because creep intensity depends more on microstructures, such as the conformation of molecular chains in the substance, or interactions among cells than on R/T ratio and area ratio image features.

Change of relaxation properties of bamboo in the longitudinal and radial direction were examined on the basis of results of creep measurement and the micro-structure observation in cross section using the stereoscopic microscope. Creep compliance J (t) was greater in the bottom and inner side than in the top and outer side. J (t) versus ln(t) was represented by the Nutting equation. The number of vascular bundle per mm 2 , that is its dispersion, increases with locating to the top and outer side of bamboo. Various values of relaxation properties, J (t), J (t)−J(0), and dJ (t)/dlnt, was characterized by just density of bamboo which was linear to the number of vascular bundle per mm 2. Our results show that bamboo changes relaxation properties in the longitudinal and radial direction by controlling the dispersion of vascular bundles.

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