The oxidative stress on cells causes modification of various cellular components such as proteins, lipids and nucleic acids, and leads to the damage of cell structure and function. The host defense system recognizes oxidatively damaged erythrocytes in two ways. One includes autoantibody to sialylated poly-N-acetyllactosaminyl carbohydrate chains of band 3 glycoprotein. The antibody binds to the oxidized cells by recognizing the carbohydrate chains on the cells. The antibody binding should lead to phagocytic removal of the oxidized cells from the circulation by macrophages. The other mechanism is direct recognition of the oxidized cells by macrophages through recognition of sialosaccharide chains of glycophorin A of the oxidized cells. These two mechanisms of recognition and removal of oxidatively damaged cells may be regarded as the secondary antioxidant defense at cellular level to maintain homeostasis of the body.

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Recently, social concerns regarding tap water quality have increased mainly because of the possible reduction in safety due to the contamination of tap water with various chemicals and the increase of strange odors and tastes in tap water as a result of the eutrophication in resource water. Consequently, the Ministry of Health and Welfare conducted a detailed two-year investigation of the Water Quality Standards of the Water Works Law by summoning an expert committee, and as a result, totally revised the Standard in December 1992. This was the first overall revision since 1958 when the Water Quality Standard was established, and an additional 21 items, including mainly hazardous chemicals including pesticides and chlorinated by-producets, were newly added. Simultaneously, 26 monitoring items on hazardous contaminants guidelines which should be applied, when necessary. Analytical methods for drinking water were summarized and preparation, analytical systems and detecting limits.

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The role of a roadside buffer planting belt and road structure in controlling air pollutants was studied by determining the distribution of NO₂ in open fields and planting areas near roads of various structure. NO₂ concentration was found to decrease with distance from the road, but the reduction in planting sites was greater than in open fields. Roadside planting at a level road structure was found to reduce NO₂ concentration by 3.5 ppb at 10 m and by 2.3 ppb at 150 m from the road. Road structure influenced NO₂ concentration 5 m from the road ; the concentration decreased as height of the road noise barrier increased, and this effect was enhanced by the presence of a planting area at all structures except the bank road.

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In this study a modified sealed method is developed for chemical oxygen demand (COD) determination. For time-saving and ease of operation, an oven and ultraviolet spectrophotometer were chosen as heating equipment and chromate detector, respectively. Organic compounds such as formic acid, acetic acid, oxalic acid, malonic acid, aniline, glycerol, glucose and potassium hydrogen phthalate were used as prematerials to modify a calibrated equation in the final detection at 348 nm in the ultraviolet spectrophotometer. A masking effect of mercury sulfate to chloride ion was also evaluated with the digestion agent. The results show that the masking agent, if necessary, must be used before addition of the digestion agent, and they demonstrate an excellent inhibition from 1 to 1000 mg/l of chloride ion existing in the water sample. During actual sample tests, the modified sealed oven-UV method performed very appropriately in environmental samples being accurate and with a low detection limit of 9.26 mg/l.

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The study was conducted using a quaternary ammonium disinfectant, didecyldimethyl ammonium chloride (DDAC), whose minimum lethal concentration (MLC) against Staphylococcus aureus was 32 μg/ml. No remaining viable cells were detected even after a short 20 s treatment with DDAC at the MLC. Treatment with DDAC caused to form blebs on the cell surface, and K⁺, 260 nm absorbing materials and phospholipid leaked out from the cells. The experiment using ¹⁴C-labeled DDAC showed that the disinfectant was taken up in a biphasic curve to the cell regardless of the treatment temperature or time. The radioactivity was distributed significantly in the membrane fraction and the cytoplasm fraction. Tetramethyl ammonium chloride showed no biocidal activity and had no effect on the activity or uptake of DDAC. From these results, it was deduced that DDAC, at bactericidal levels, is adsorbed physicochemically, by hydrophobic interaction, onto the cell membrane, where it can react with lipid to cause significant damage to the structure and function of the membrane, leading to death.

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The minimum lethal concentration of didecyldimethyl ammonium chloride (DDAC), a quaternary ammonium disinfectant, was 32 μg/ml against Staphylococcus aureus, but the presence of 0.7% polysorbate 80 raised it to 250 μg/ml. Viable cells were recovered from the treatment mixture at 32 μg/ml for up to 1 min when polysorbate was added, although no survivors were detected even at 20 s without polysorbate. The non-ionic surfactant depressed all the phenomena arising from the DDAC treatment including the uptake of DDAC by the cell, leakage of intracellular components, i.e. K⁺, 260 nm absorbing materials, and phospholipid. From these results, it is deduced that polysorbate interferes with the uptake of DDAC and also can remove the disinfectant in micelles from the cell surface, resulting in prevention of the DDAC damage to the structure and function of cell membrane.

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The procedure for the determination of the main metabolites of malathion (MA), malaoxon (MO), malathion dicarboxylic acid (DCA), malathion α-, β-monocarboxylic acid (α-, β-MCA), desmethyl malathion (DM-MA), in addition to unchanged MA was investigated using positive-ion mode thermospray liquid chromatography-mass spectrometry (TSP-LC/MS). Following the solid-phase extraction of the sample at pH 2 using Sep-Pak C₁₈ cartridge with methanol as eluent, the extract was analyzed on TSP-LC/MS. LC analyses were performed on C₁₈-bonded phase using methanol-100 mM ammonium acetate (60 : 40 v/v, pH 3.65 with trifluoro acetic acid) as eluent at a flow rate of 1.0 ml/min. Every mass spectrum of MA and its metabolites provided both the protonated molecular ion [M+H]⁺ and the ammonium adduct ion [M+NH₄]⁺. By the solid-phase extraction, they were recovered relatively well, and the detection limits were ranged from 0.2 μg/ml to 2.5 μg/ml by scan mode, ranged from 5 ng/ml to 200 ng/ml by selected ion monitering (SIM) mode. In the urine sample, the coefficients of variations for the prepared method by SIM mode were ranged from 3.3% to 7.2% at 500 ng/ml level of each metabolite. For a blood sample of a female, who had committed suicide by taking MA, TSP-LC/MS analysis were attemped following the prepared method, the metabolites such as α-MCA were detected, and it was possible to prove that she had taken MA.

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A specific and sensitive enzyme-linked immunosorbent assay using immobilized mouse monoclonal antibodies to okadaic acid (OA), OA423-3 and OA958-2, which are resistant to organic solvents, has been established to determine OA and its analogs (OAs). OA423-3 (IgG_1-x), which bound only OA in 10% (v/v) aqueous methanol, is useful to determine OA selectively. The quantitative determination range of OA was 70 pg-6.0 ng/ml, and the coefficient of variation (cv) within six independent analyses was 15.4% at the OA concentration of 0.52 ng/ml. Besides, OA958-2 (IgG_1-x), which equally bound OA, dinophysistoxin-1 (DTX₁) and 7-O-palmitoyl-dinophysistoxin-1 (Pal-DTX₁) in methanol, is successful in determing total OAs. The quantitative determination range of each toxin was 4.1 ng-2.2 μg/ml for OA, 4.9 ng-2.25 μg/ml for DTX₁ and 11.0 ng-1.15 μg/ml for Pal-DTX₁, respectively. The cv values were 12.9-17.5% at the toxin concentration of about 100 ng/ml. As to determine each of OAs, the mixture of OAs was first partitioned between n-hexane and 60% (v/v) aqueous methanol. Total amount of OA and DTX₁ in 60% (v/v) aqueous methanol and the amount of Pal-DTX₁ in n-hexane were determined using OA958-2 in methanol. And the amount of OA in 60% (v/v) aqueous methanol was determined using OA423-3 in 10% (v/v) aqueous methanol. The amount of DTX₁ was calculated by subtracting the amount of OA from the total amount of OA and DTX₁. The determination of the mixture of 500 ng each of OAs resulted in 1591 ng as OA for total OAs, 500 ng for OA, 474 ng for DTX₁ and 519 ng for Pal-DTX₁, respectively. The recovery test using nontoxic scallops and blue mussels fortified with 1.0, 2.0 and 10 μg of OA, DTX₁ or Pal-DTX₁/g of hepatopancreases resulted in 100.8-107.8% of recovery rates.

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In order to elucidate the series of the biological effect of the rare earth elements, a 28-d repeated oral administration test was conducted in Slc : Wistar rats of each sex by gavage at doses of 0, 40, 200 or 1000 mg/kg/d of YCl₃·6H₂O with the pair feeding group. Additionally two more groups (0 mg/kg, 1000 mg/kg) of both sexes were maintained for a 14-d recovery period after the 28-d administration. Body weight and food consumption were measured, and hematological, serum-biochemical and histopathological examination were performed. The concentrations of yttrium and essential elements in organs were determined by ICP-MS or ICP-AES. These overall data on yttrium were compared with our previous study on lanthanum performed by the same protocol. The results were as follows. (1) The number of eosinophilic leucocytes increased in rats of both sexes dose-dependently. (2) At a dose of 1000 mg/kg, hyperkeratosis in the forestomach of both sexes, eosinophilic leucocyte infiltration in the submucosa of the stomach of both sexes, erosion and dilatation of gastric gland of the glandular stomach in males, and swelling of the glandular stomach epithelium in females were found. These results suggest that yttrium is irritant to the stomach mucosa. (3) At doses higher than 200 mg/kg, a significant decrease of the serum cholinesterase activity was observed in females. (4) At the 1000 mg/kg lanthanum-dosed rats of our previous study, the serum transaminase activity increased in both sexes. On the other hand, there were no changes between control and yttrium-dosed rats. (5) Yttrium was accumulated in the kidney, femur, liver and spleen, in a dose-dependent manner. (6) The highest accumulation of yttrium was found in the kidney. According to the previous lanthanum study, the highest accumulation of lanthanum was observed in the liver. (7) The total amount of yttrium acumulation in rats was about 50 times as much as that of lanthamum. (8) The sex-dependent differences were observed in terms of the irritating reaction of the stomach mucosa, the reduction of the serum cholinesterase activity and the accumulation of yttrium in the kidney. (9) These results show that yttrium could be absorbed through the digestive tract. (10) Iron concentrations in the liver, kidney and spleen, and barium and strontium concentrations in the femur were dose-dependently decreased in both sexes of yttrium-treated rats. Both yttrium and lanthanum are classified as rare earth elements and the present study revealed that the biological effects of yttrium were very similar to those of lanthanum except the accumulating patterns and volumes. On the other hand, in contrast to the fact that lanthanum was hepatotoxic compound, yttrium had no effect on liver, which seems to be due to the difference of their accumulating patterns.

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A simple method for the analysis of glycyrrhetinyl stearate (SGS) in cosmetics by high performance liquid chromatography has been developed. A YMC Pack polyamine column is very stable compared with Nucleosil NH₂ in the acidic phase. The optimum condition for the separation of SGS in cosmetics are as follows : column, YMC Pack Polyamine (4.6 mm i.d.×250 mm, 5 μm) ; mobile phase, methanol-tetrahydrofuran-acetic acid (80 : 20 : 0.05), 1 ml/min, column temperature, ambient. Detection wavelength ; 248 nm. Recoveries of SGS from 6 types of cosmetic are more than 96%. These results obtained here indicate that this method is suitable for detecting the SGS in cosmetics.

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Trihalomethane levels and parameters (pH, temperature, KMnO₄-consumed values and residual chlorine) in tap water samples obtained from Kinki area in Japan were measured. Furthermore, we studied the effect of the addition of activated carbon during the preparation process on the trihalomethane levels in tap water. Sixty eight samples of tap water were collected from the domestic water supply of Hyogo, Osaka, Kyoto and Nara prefectures. No significant correlation was found between the trihalomethane levels and parameters. On the other hand, the addition of activated carbon to tap water significantly decreased the trihalomethane levels.

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The stability of the standard solutions for 20 organophosphorus, 19 organonitrogen and 7 pyrethroid pesticides during storage under different conditions (solvent, concentration of pesticides, with or without light) was investigated by gas chromatograph (GC). All of the investigated 46 pesticides were stable during twenty days under all conditions except storage under sunlight. It was found that 12 pesticides dissolved in acetone in low concentration decreased under sunlight. Photo-changed compounds of aldicarb, disulfoton, and fensulfothion in acetone were investigated by GC. It was clarified that these pesticides were gradually changed into their oxydative products (sulfoxide and sulfone). Consequently, it is recommendable that the standard solution for pesticides should be dissolved in hexane, in high concentration and kept in the dark.

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