Methyl mercury (MeHg) administered to animals is biotransformed gradually to inorganic Hg. Several studies have revealed that there are two degradation processes, by intestinal microflora and animal tissues themselves. However, the mechanism responsible for the latter process has been little studied. Recently, the degradation of MeHg and ethyl mercury (EtHg) was clarified to occur via a reactive oxygen-mediated process. Thus, this review describes several examples of the reactive oxygen-producing systems capable of degrading MeHg and EtHg and their degradation mechanism, and discusses about their involvement in the biotransformation of MeHg in the animal body. Briefly, MeHg and EtHg were dealkylated by reactive oxygen species such as ·OH, HOCl and ¹O₂ in several enzymatic or photochemical reactive oxygen-producing systems. MeHg and EtHg degradation also occurs in phagocytic cells (polymorphonuclear leukocytes, macrophages, monocytes, and eosinophils) and liver microsomes having a reactive oxygen-producing system. Furthermore, there are some in vivo evidence that the reactive oxygen-producing system may actually function in the biotransformation of MeHg.

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Heme oxygenase (HO : EC 1.14.99.3) is a key enzyme for heme catabolism and catalyzes the oxidative degradation of heme to form biliverdin IXa, an immediate precursor of bilirubin. The HO activity can be induced by treatment with hemin, the substrate itself, as well as with various other non-heme stress inducers. Recently, it has been shown that HO is a major 32 kDa stress protein inducible by treatments with heavy metals, heat shock, or acute phase inducers. The induction of HO is considered to be a member of the defense system against environmental hazards, because bilirubin is one of the antioxidants. Among two isozymes of HO, i.e., HO-1 and HO-2, only HO-1 is inducible. In the present article, therefore, we described the molecular mechanisms of HO-1 gene activation by environmental hazards. We also discussed the HO-1 gene regulation during differentiation of erythrocytes and monocytes.

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The way of human existence on the earth is largely influenced by the changes in earth environment and how to manage and conserve it is very important to human beings. Recently, however, the earth environment is destroyed by El Nino phenomena, desertification, greenhouse effect, destruction of ozone layer, acid rain, etc. Then the investigation and research of the earth environment by remote sensing technology are attracting world attention. It is also applied to the research of vegetation (agriculture and forest), ocean land use, civil engineering, disaster prevention, atmosphere, geographical information, etc. A method to derive vegetation indices used to know activation of green vegetation is introduced. These indices are also used to detect desertification phenomena. From the viewpoint of environment, human beings living in natural environment must adapt themselves to the environment without changing it.

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The effects of lanthanum, terbium, and ytterbium on the in situ small intestinal absorption of D-glucose, D-fructose, and maltose in mice were studied. The absorption of D-glucose (11.1 mM), which is actively absorbed from the small intestine in situ, was significantly decreased in the presence of LaCl₃ (La) and TbCl₃ (Tb) at concentrations of 1, 2 and 4 mM, and YbCl₃ (Yb) at concentrations of 2 and 4 mM in the lumen. The absorption of D-fructose (2.75 mM), which is absorbed by facilitated diffusion, was significantly decreased by these metals at the concentration of 4 mM, The absorption of maltose (11.1 mM) was also significantly decreased by these metals at concentrations of 1, 2, and 4 mM. The whole intestinal accumulation of La, Tb, and Yb in the perfusion experiment was great. The activities of Na⁺, K⁺-ATPase and maltase in the small intestinal mucosa were significantly decreased by these metals in the in situ perfusion experiment and the in vitro experiment. A scanning electron micrograph of the jejunum after the in situ perfusion experiment with each saccharide plus each metal showed mucosal damage. These results indicate that La, Tb, and Yb cause damage to intestinal mucosa and inhibit the activities of Na⁺, K⁺-ATPase and maltase in the intestinal mucosa, resulting in the inhibition of the intestinal absorption of D-glucose, D-fructose, and maltose.

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Cyclohexanol and cyclohexanone were used in large quantity as materials for chemical products, for example, for the synthesis of adipic acid. In this paper, the process of ozonation of cyclohexanol and cyclohexanone under ultraviolet irradiation was studied. Ozonation combined with ultraviolet irradiation was used for the destruction of organic refractry in water. Cyclohexanol and cyclohexanone were readily oxidized to give adipic acid, glutalic acid, succinic acid, malonic acid, glycolic acid and their derivatives, which were further oxidized to give oxalic acid and formic acid. Simultaniously, the total organic carbon decreased effectively. By the ozonation under neutral conditions without ultraviolet irradiation, cyclohexanone was not oxidized, but cyclohexanol was oxidized to give cyclohexanone. On the basis of these results, it was found that the ozonation under ultraviolet irradiation was markedly effective for the degradation of cyclohexanol and cyclohexanone, compared with the ozonation alone.

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Toxicological studies of carbonyl compounds derived from oxidized lipids on primary cultured rat hepatocytes were investigated. As carbonyl compounds, saturated aldehyde, α, β-unsaturated aldehyde, glyoxals and malondialdehyde were used. Hepatocytes isolated from male Wistar rats by the collagenase perfusion method were cultured in 35 mm dishes in an atmosphere of 5% CO₂-95% air at 37°C. Rat hepatocytes in culture for 24 h were incubated in Williams'E medium containing carbonyl compounds. Hepatotoxicity was estimated as the leakage of hepatic enzymes such as lactate dehydrogenase (LDH) and glutamic-oxalacetic transaminase (GOT) from the cells to medium. LDH and GOT activities were determined by an automatical analyzer. The order of hepatotoxic potency was as follows : glyoxals>α, β-unsaturated aldehydes>saturated aldehydes. Malondialdehyde had not hepatotoxicity. Hepatotoxicity of α, β-unsaturated aldehyde was inhibited by the addition of ascorbic acid and glutathione, whereas that of autoxidized methyl linoleate (peroxide value=2538 meq/kg and carbonyl value=872 mmol/kg) was inhibited by the addition of not only 3-tert-butyl-4-hydroxyanisole (BHA) and N, N'-diphenyl-p-phenylenediamine such as antioxidant, but also ascorbic acid and glutathione. From the above results, it is suggested that both hydroperoxides and α, β-unsaturated aldehydes contribute to the hepatotoxicity of autoxidized methyl linoleates.

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EMIT, gas chromatography-mass spectrometric (GC-MS) and thermospray high performance liquid chromatography-mass spectrometric (LC-MS) methods for the determination of triazolam (TRZ) and its metabolites (1-hydroxymethyltriazolam (α-HT) and 4-hydroxytriazolam (4-HT)) in the human urine were investigated. TRZ was analyzed by EMIT st Urine Benzodiazepine Assay. EMIT cutoff was 50 ng/ml of TRZ. TRZ and its metabolites were extracted from the human urine using Sep-Pak C₁₈ cartridge with dichloromethane-methanol (90 : 10 v/v) as the eluent. The eluate was evaporated to dryness under stream of N₂. The residue was dissolved in 1 ml of methanol, 50 μl was injected into the LC-MS. LC analyses were performed on a TSKgel Octyl-80Ts in the solvent system of 100 mM ammonium acetate-methanol (50 : 50 v/v) at a flow rate of 1.0 ml/min. For GC-MS, the extract was derivatized at 90°C for 30 min with 50 μl BTZ. GC analyses were performed on a fused silica column DB-1. The column temperature was 290°C. The detection limits of these compounds by scan mode were 800 ng/ml for α-HT and 4-HT with GC-MS, 50 ng/ml for TRZ and α-HT, 100 ng/ml for 4-HT with LC-MS and those by selected ion monitoring mode were 50 ng/ml for α-HT, 100 ng/ml for 4-HT with GC-MS, 5 ng/ml for TRZ and α-HT, 10 ng/ml for 4-HT with LC-MS.

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Because of the lack of the convenient assay to detect the heat-stable enterotoxin II of Escherichia coli (STII), STII produced from E. coli in clinical isolates has not been inspected in regular clinical examinations. And it has not been examined whether these isolates possess a gene for STII, too, as a colony hybridization test which is the conventional method to detect strains possessing the specified gene of bacteria is a troublesome work for inspectors in regular bacteriological examination laboratory. In this study, we developed two methods to detect STII and its gene. One was the enzyme-linked immunosorbent assay (ELISA) to detect STII and the other was the polymerase chain reaction (PCR) to detect the gene for STII. Using these methods, we examined STII and its gene from 120 strains isolated from stools of porcines with diarrhea in Brazil. At first, a colony hybridization test employing a DNA fragment encoding the STII gene was performed to find strains possessing the STII gene. Twenty-three strains out of 120 porcine strains were found to possess STII genes. In ELISA, samples from these 23 strains which were positive in the colony hybridization test showed positive reaction and those from other strains which were negative in the colony hybridization test showed negative reaction. To apply PCR for the detection of strains possessing the STII gene, we designed the primer set to detect a 380-base pair (bp) fragment. The 380-bp fragments were enzymaticaly amplified from DNAs of these 23 strains which were positive in the two tests described above but not from those of other strains which were negative in these tests. These results showed that ELISA and PCR developed in this study are specific for STII and that these developed methods are useful for the screening of large number of clinical strains.

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The analytical method for N-ethyl-3, 4-methylenedioxyamphetamine (EMDA), one of the hallucinogenic phenethylamine derivatives newly controlled in Japan, was investigated in several aspects of forensic chemical analysis. The standard EMDA was synthesized from piperonylmethylketone. We analyzed EMDA, its related compounds (3, 4-methylenedioxymethamphetamine (MDMA), 3, 4-methylenedioxyamphetamine (MDA) and ethylamphetamine (EA)) and a seized sample containing EMDA, methamphetamine and caffeine using color test, thin-layer chromatography (TLC), infrared spectrometry (IR), gas chromatography (GC) and gas chromatographymass spectrometry (GC-MS). Under the analytical conditions described here, we succeeded in complete separation and identification of these drugs. It may also be possible to apply our method for the intake of drug abuse such as EMDA.

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Capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) with sodium dodecyl sulfate (SDS) as an anionic carrier were applied to the analysis of nine principal components of eye lotion. Simultaneous separation of these components except cyanocobalamin (VB₁₂), which has the same migration time with that of electroosmotic flow, was achieved by CZE using a 72 cm×50 μm i.d. fused silica capillary tube filled with 20 mM borate buffer (pH 10) at 25 kV DC voltage with UV detection at 200 nm. Under these conditions, the peak of chondroitin sulfate (CS) was overlapped with that of aspartic acid in case the latter was contained in the sample as a co-existing component. However, when pH was decreased to 9, CS was separated from other components and also from aspartic acid, and gave a more shapely peak. VB₁₂ could be separated from other components by MEKC with 20 mM borate buffer (pH 10) containing 40 mM SDS. The applicability to the determination of nine principal components of eye lotion is demonstrated.

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