Abstract:As the first step to get historical background data for physiological examinations in juvenile dogs, hematology and blood chemistry data obtained from juvenile beagle dogs (less than 3 months of age) used in the control group of toxicity studies conducted in our laboratory were summarized and compared with those obtained from adult beagle dogs (6 months of age). In the hematological examination, growth of beagle dogs was shown to be associated with increases in erythrocyte parameters and with decreases in reticulocyte and leukocyte counts. In the blood chemical examination, growth of beagle dogs was shown to be associated with increases in aspartate aminotransferase, alanine aminotransferase, and creatinine and with decreases in creatine phosphokinase, glucose, total cholesterol, and calcium. The differential leukocyte ratio showed no age relation, but the actual count showed a tendency toward decrease. Alkaline phosphatase showed a tendency to increase from 0 months of age to 3 months of age, but it decreased at 6 months of age. The present results were roughly similar to those previously reported.
The in vivo mutation assay using the X-linked phosphatidylinositol glycan class A gene (Pig-a in rodents, PIG-A in humans) is a promising tool for evaluating the mutagenicity of chemicals. Approaches for measuring Pig-a mutant cells have focused on peripheral red blood cells (RBCs) and reticulocytes (RETs) from rodents. The recently developed PIGRET assay is capable of screening >1×10 RETs for Pig-a mutants by concentrating RETs in whole blood prior to flow cytometric analysis. Additionally, due to the characteristics of erythropoiesis, the PIGRET assay can potentially detect increases in Pig-a mutant frequency (MF) sooner after exposure compared with a Pig-a assay targeting total RBCs (RBC Pig-a assay). In order to test the merits and limitations of the PIGRET assay as a short-term genotoxicity test, an interlaboratory trial involving 16 laboratories was organized by the Mammalian Mutagenicity Study Group of the Japanese Environmental Mutagenicity Society (MMS/JEMS). First, the technical proficiency of the laboratories and transferability of the assay were confirmed by performing both the PIGRET and RBC Pig-a assays on rats treated with single doses of N-nitroso-N-ethylurea. Next, the collaborating laboratories used the PIGRET and RBC Pig-a assays to assess the mutagenicity of a total of 24 chemicals in rats, using a single treatment design and mutant analysis at 1, 2, and 4 weeks after the treatment. Thirteen chemicals produced positive responses in the PIGRET assay; three of these chemicals were not detected in the RBC Pig-a assay. Twelve chemicals induced an increase in RET Pig-a MF beginning 1 week after dosing, while only 3 chemicals positive for RBC Pig-a MF produced positive responses 1 week after dosing. Based on these results, we conclude that the PIGRET assay is useful as a short-term test for in vivo mutation using a single-dose protocol.
The fusel oil in whisky had no effect on the ethanol-induced emetic response, but it suppressed taste-aversion behavior in animal models of hangover symptoms. These results suggest that the fusel oil in whisky alleviates hangover, contrary to the common belief.
KEY WORDS: abalone larval metamorphosis, d d d d -aminovaleric acid, crustose coralline algae, Hydrolithon samoense , settlement-inducing substance.Abalone larvae swim for several days before they metamorphose into a miniature adult organism. Crustose coralline algae (CCA) induce substratumspecific metamorphosis of abalone larvae. The metamorphosis is triggered by chemical substances, such as g -aminobutyric acid (GABA) 1 and thyroid hormones, 2 but these substances have not been found as free compounds in CCA. Morse and Morse studied settlement-inducing substances from CCA and suggested that settlement was controlled by precursors or metabolites of phycoerythrin structurally related to GABA. 3 However, the active substances in the algae remained unspecified. 4 Seki et al . reported that abalone larval metamorphosis was induced by dibromomethane produced from algal surfaces. 5 The chemical structure of CH 2 Br 2 is quite different from that of GABA. The present study on inducing substances in CCA focused on low-molecular weight compounds, and resulted in the isolation of d -aminovaleric acid (5-AVA) as an inducer.Larvae of two species of abalone Haliotis discus discus and Haliotis discus hannai were supplied by Shizuoka Prefectural Sea Farming Center, Shizuoka Prefectural Thermal Effluent Utilization Research Center, and Yamagata Prefectural Sea Farming Center. Three or 4 days after fertilization at 18-20 ∞ C, the veliger larvae were transported to the University of Shizuoka. Assays were performed by slight modifications of the procedure described previously. 2 Swimming larvae, which were competent to metamorphose, were placed in 24-well tissue culture dishes at densities of 20-40/well. Assays were performed in the dark at 19 ± 1 ∞ C in 2.0 mL sterilized natural seawater containing the tested samples and 150 m g/mL each of potassium penicillin G and streptomycin sulfate (Meiji Seika Kaisha Ltd, Tokyo, Japan). Two controls were included, one containing only seawater (negative) and the other 1 m M baclofen (positive), a potent GABA B receptor agonist. 6 The percentage of metamorphosis in each well was determined at 96 h with the use of a microscope at 40 ¥ magnification. The assays were conducted in quadruplicate, and the results were shown as the mean value of four wells.Stones covered with the CCA Hydrolithon samoense were collected at Osezaki (Shizuoka Prefecture, Japan). Algae-covered stones (estimated weight of wet algae, 300 g) were directly extracted with distilled water at 4 ∞ C for 2 days. After filtering, the filtrate was lyophilized to give powdered extract (11 g). The extract was separated by a series of chromatographic methods (Fig. 1) to give an active fraction (fr-1-2-3, 20 mg). The conditions for chromatography were as follows: (i) Diaion HP-20, solvent: H 2 O AE 50% aqueous methanol AE methanol; (ii) activated charcoal, solvent: H 2 O AE 50% aqueous ethanol AE 50% aqueous ethanol containing 1% acetic acid; (iii) Amberlite CG-50 (H + form; Rohm and Haas Co., Philadelphia, PA, USA), solvent H 2 O AE ...
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