Paraquat (1, 1'-dimethyl-4, 4'-dipyridylium salt) is a widely used non-selective herbicide in the world. The herbicide is highly lethal to human, and its toxicity is characterized by damage to the lung. Many peoples have died through accidental, or suicidal and homicidal ingestion of paraquat in every year, and the numbers of the dead have recently increased year by year, in Japan. Much attention is being denoted to such an increment of the dead, as a social problem. In this review, paraquat poisoning and its identification (containing its related compound, diquat) are dealt with in two sections. In the first section, toxicity and metabolism of the herbicide, a possible mechanism and therapeutics of the poisoning are discussed. The second section deals with the methods used to detect and analyse the herbecides (paraquat and diquat) in human body fluids and post mortem tissue resulting from intentional or accidental ingestion. Furthermore, analyses of trace amounts of the herbicides in animal tissue, plant material, soil and river are covered. The methods are as follows : spectrophotometry, paper partition-and thin layer-chromatography, high performance liquid chromatography, gas liquid chromatography, biological assay (immunoassay etc.) and micellaneous. The methods would be applicable to the identification of the samples in the fields of forensic chemistry, clinical and environmental toxicologys.

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Initial chemical events caused by mutagenic heteroaromatic amines are discussed. 2-Amino-6-methyldipyrido [1, 2-a : 3', 2'-d] imidazole (Glu-P-1) and 3-amino-1-methyl-5H-pyrido [4, 3-b] indole (Trp-P-2) are potent mutagens isolated from pyrolysates of glutamic acid and tryptophan, respectively. These carcinogens are N-hydroxylated with microsomes to give the corresponding hydroxylamines. These hydroxylamines are O-acylated with cytosol to give the corresponding N-acyloxy derivatives, which react with DNA. The structures of the modified nucleic acid bases with Glu-P-1 and Trp-P-2 were determined to be 2-(guanin-8-yl) amino-6-methyldipyrido [1, 2-a : 3', 2'-d] imidazole (Gua-Glu-P-1) and 3-(guanin-8-yl) amino-1-methyl-5H-pyrido [4, 3-b] indole (Gua-Trp-P-2), respectively. Syntheses of these heteroaromatic amines, these modified nucleic acid bases and metabolically activated hydroxylamines are described. Reactions of model compounds of the ultimate forms of these heteroaromatic amines with nucleic acids were investigated. Thus, the pathway of the chemical modification of DNA with Glu-P-1 and with Trp-P-2 were established chemically. In addition, the same chemical modification of DNA with Glu-P-1 and with Trp-P-2 were observed in vivo (rats). In the pathway, intercalation of these heteroaromatic amines is an important factor which makes the covalent reaction facile and determines the mutagenic activity. Intercalative ability of Glu-P's were established by physical methods. The chemical modification of DNA is quite specific to the 8-position of guanine moiety, and the guanine moieties in G-C rich regions are preferentially modified. The established pathway of chemical modification of DNA with Glu-P-1 and with Trp-P-2 provides a fundamental standpoint in the study on chemical carcinogenesis caused by these heteroaromatic amines.

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To examine the mechanism of the enhancement of tocopherol concentration in the testis of rats when the inflammation was induced by CdCl₂ administration, we measured concentrations of tocopherol homologues in the serum, liver and testis of CdCl₂-treated rats as a function of time. In the serum, α-and β-tocopherol concentrations increased significantly at 15 h after CdCl₂ administration, and those levels in the testis increased significantly at 24 h or 48 h after the metal administration. No significant change of the concentrations of tocopherols in the liver was seen by CdCl₂ administration. On the other hand, the incorporations of ³H-α-tocopherol into the testis and the epididymis, when injected into the rat treated with CdCl₂, increased 6-and 8-fold as compared with those in control rats, respectively. These results indicate that α-tocopherol is actively incorporated into the inflammed testis via blood stream.

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Simultaneous determination of carboxylic acids and inorganic anions was investigated by photometric ion chromatography with phthalate solution as an eluent. The retention time and the peak area of carboxylic acids changed remarkably with eluent pH. The optimum conditions at present were as follows : analytical column, OYOBUNKO ASA-4000 (4.6 mm i.d.×25 cm) ; eluent, 5×10^-4 M disodium phthalate ; flow rate, 2 ml/min ; column temperature, 40°C ; detection wavelength, 240 nm ; injection volume, 100 μl. The detection limits for several carboxylic acids as 3 times noise were 0.05-0.07 mg/l in sample solution. Their calibration curves showed straight lines by the peak area method. The present method has an advantage to determine simultaneously not only carboxylic acids but also inorganic anions. Under the condition described above, both carboxylic acids and inorganic anions in several liquid foods were easily determined by direct injection of the sample prepared with only dilution.

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Effects of various reagents on cadmium and metallothionein concentrations in the liver, kidney, small intestine and pancreas were examined by simultaneous injections of the reagent (i.p.) and cadmium (3 mg/kg, s.c.) to mice. Compared to the mice injected with cadmium alone, little effect on the cadmium and metallothionein concentrations was observed by the injection of o-iodosobenzoic acid, KBrO₃, ascorbic acid or glutathion. The concentration of cadmium and metallothionein in the four tissues decreased significantly after the injection of ethylenediaminetetraacetic acid. By the injection of diethyldithiocarbamic acid, the concentration of cadmium decreased in the four tissues and the concentration of metallothionein decreased in the liver, kidney and small intestine. By the injection of phytine, the concentration of metallothionein in the liver increased significantly. A significant increase in metallothionein concentration in the liver was observed by the injection of olive oil (10 ml/kg) or phytine (500 mg/kg) alone. By the pre-injection of these reagents, mortality of mice injected with cadmium (10 mg/kg, s.c.) decresed significantly than that of mice injected cadmium alone.

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In order to clarify the influences of particulate substances produced by studded tires of automobiles on human health, the investigation was made on the mutagenicity and benzo (α) pyrene (B (α) P) contents in soils collected at road-sides of Sendai city in March and August, 1981. B (α) P contents in March (0.04-0.5 μg/g soil) were higher than that in August (0.04-0.11μg/g soil), while the mutagenic activity of soils to S. typhimurium TA98 with S9 mix in March were much lower than that in August. The influences of extract of road-coating-asphalt to the mutagenicity of B (α) P and AF-2 were studied to clarify the above results of contradiction. The organic substances in particulates of road-coating-asphalt produced on a large scale by studded tires of automobiles in winter were found to have a suppressing effects on the mutagenic activity of B (α) P. As this suppression was not observed in case of AF-2, the inhibition of the activity of S9 by the extract of road-coating-asphalt may be involved in the above experimental results.

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In the present studies, the colour reaction mechanism of DPD (N, N-diethyl-p-phenylenediamine) method was studied to know the optimum condition for determination of residual chlorine in water. HOCl (hypochlorite) and KMnO₄ (permanganate) were used as oxidizing agents. When the rate of the reaction mixture was more than 0.4 mol DPD per 2 equivalent HOCl and 0.8 mol DPD per 2 equivalent KMnO₄, though the absorbance at 550 nm was low, the amount of oxidizing agents was able to be determined quantitatively by ferrous ammonium sulfate (FAS) titration method. When the rate of the reaction mixture was less than 0.4 mol DPD per 2 equivalent HOCl and the region of 0.3-0.8 mol DPD per 2 equivalent KMnO₄, it was not able to be titrated by FAS, because no DPD color was developed in the reaction mixture. When 28.6 mol DPD was added subsequently to the mixture, there occurred colouration. The colouration by the subsequent addition of DPD is based on the formation of semiquinone from quinonediimine and DPD. The symproportionation constants to semiquinone were 3.02×10⁸ K/M^-1 (HOCl) and 3.07×10⁸ K/M^-1 (KMnO₄). It is concluded from these results, in order to determine the amount residual chloride in water accurately by DPD ferrous titrimetric method or DPD colorimetric method, more than 5 mol DPD is required for 1 mol chlorine.

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Twenty-two kinds of oil samples extracted from instant Chinese noodles were analyzed on their composition of fatty acid methyl esters by GC. Four main fatty acids in the oil were 18 : 1, 16 : 0, 18 : 2, and 18 : 0, and another trace ones detected were 14 : 0, 16 : 1, 17 : 0, 17 : 1, 18 : 3+20 : 0, 20 : 1, and 20 : 2. Constraction values of these four main fatty acids were used to evaluate and to calculate the difference among the six producing companies by a personal computer with the analytical method of principal component analysis. Samples were divided into three groups. The constraction values of company B was similar to that of the palm oil and another ones of companies A and E were also similar to that of the mixed oil with the ratio of 25 to 75 on the palm oil and lard.

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One hundred poisons and their related compounds including pesticides, hypnotics, psychotropics, narcotics, local anesthetics etc., have been classified into four divisions by relative Rf values to standard maker on silica gel thin layer chromatography, by use of four developing solvents and seven chromogenic reagents. The markers used were methyl yellow, methyl red, tetrabromophenol phthalein ethylester, malachite green and rhodamine B. It is decided that the first division is pesticides and some psychotropics, the second is hypnotics and some pesticides, the third is psychotropics, local anesthetics, narcotics and others and the fourth is sympathomimetics and others.

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A concentration of metallothionein in the human tissues was determined and the following results were obtained. 1. The concentration of metallothionein in the liver in eight of nine cases was higher than 100 μg/g. Metallothionein in the liver was Zn, Cu, Cd-thionein. A strong, positive relationship was found between zinc and metallothionein concentrations (γ=0.987, p<0.01). The regression equation was MT (μg/g)=-168+14.5×Zn (μg/g). 2. Mean±S.D. of the concentration of metallothionein in the kidney was 933±177 μg/g. Metallothionein in the kidney was abundant in cadmium. The most part of cadmium in the kidney was bound to metallothionein. 3. Although the concentration of metallothionein was high in one case of pancreas (168 μg/g), the concentration of metallothionein in the lung, heart or spleen was less than 20μg/g. These results indicate that the concentration of metallothionein in the human liver and kidney was remarkably higher than that in the mouse or rat tissues.

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