The end product of purine metabolism varies from species to species. The degradation of purines to urate is common to all animal species, while the degradation of urate is much less complete in higher animals. The comparison of subcellular distribution, intraperoxisomal localization forms, molecular structures and some other properties of urate-degrading enzymes (uricase, allantoinase and allantoicase) among animals is described. Liver uricase is located in the peroxisomes in all animals with uricase. On the basis of the comparison of intraperoxisomal localization forms, molecular weights, and solubility of liver uricase among animals, it is suggested that amphibian uricase is a transition form in the evolution of aquatic animals to land animals. Allantoinase and allantoicase are different proteins in fish liver, whereas the two enzymes form a complex in amphibian liver. The subcellular localization of allantoinase and allantoicase varies among fishes. Hepatic allantoinase is located both in the peroxisomes and in the cytosol in marine fishes, and only in the cytosol in fresh water fishes. Hepatic allantoicase is located on the outer surface of the peroxisomal membrane in the mackerel group and in the peroxisomal soluble matrix in the sardine group. Amphibian hepatic allantoinase-allantoicase complex is probably located in the mitochondria. On the basis of the previous data, changes of allantoinase and allantoicase in the molecular structure and intracellular localization during animal evolution may be as follows: fish liver allantoinase is a single peptide with a molecular weight of 54,000 and is located both in the peroxisomes and in the cytosol, or only in the cytosol. Fish liver allantoicase consists of two identical subunits with a molecular weight of 48,000 and is located in the peroxisomal soluble matrix or on the outer surface of the peroxisomal membrane. The evolution of fishes to amphibia resulted in the dissociation of allantoicase into subunits and in the association of allantoinase with the subunit of allantoicase. This amphibian enzyme was lost by further evolution.

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We studied three-week-old male Wistar rats, corresponding to the age of newly weaned human children, to understand the effect of a dietary therapy of ipriflavone combined with 1α-OH-D_3 on debilitated mandibular condyles resulting from insufficient calcium intake by observing ultrastructural alterations. Light microscopy findings demonstrated calcification and a reduction of the formation of secondary spongy bone in the low calcium diet group, increases in the formation of secondary spongy bone in the low calcium diet and standard diet group, and calcification of the chondral matrix and active ossification along with normal growth of the mandibular condyle in the low calcium diet and standard diet with supplementary ipriflavone and 1α-OH-D_3 group. In the low calcium diet group, the chondral lacunae were shaped irregularly, with sparse calcospherites and irregular collagen fibrils noted among the calcospherites. There were abundant vacuoles and lysosomes in the cytoplasm of osteoclasts, which were often active. In the low calcium diet and standard diet group, calcospherite agglutination was incomplete and some of the chondral lacunae borders were distinct. The number of osteoblasts was increased and evidence of their active transition to osteocytes was observed. In the low calcium diet and standard diet with supplementary ipriflavone and 1α-OH-D_3 group, territorial matrixes between chondral lacunae were often seen, and the chondral lacunae borders were distinct. Characteristically, most of the osteoclasts in this group were inactive and had parted from the bone matrix, while active osteoblasts lined the surface of new bone formations that were separated by a thick osteoid layer. Our results showed that insufficient calcium raised the level of debilitated bone, while supplemental ipriflavone and 1α-OH-D_3 promoted its recovery.

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Electrolyzed waters involving strong acid, weak acid and neutral waters have been widely used for sterilization and disinfection in clinical dentistry because of their excellent bactericidal and virucidal activities. In the present study, the questionnaires were performed to dental practitioners in 2000 and 2002 in order to investigate the utilizing aspects of the electrolyzed water in private offices. The questionnaire in 2000 revealed that, 25.9 and 11.1% out of 27 offices have used electrolyzed strong and weak acid waters, respectively, and one office has used both types of waters. For the two years from 2000 to 2002, the number of the user of strong acid water decreased to 12.5 % and that of weak acid water increased to 16.7 %. One office replaced the strong acid water with a newly developed neutral water and 2 offices introduced the neutral water. The primary reason for stopping the use of the strong acid water was its potential side effect to corrode metals. The factors to make the offices selected the neutral water, on the other hand, were its lesser corrosivity to metals, longer storage life of bactericidal activity and lower running cost. The users of any electrolyzed water generally appeared to satisfy the clinical performance of several sterilization.

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