The first recognized outbreaks of hemorrhagic colitis occurred in 1982 in the United State and its etiologic agent was identified to be Escherichia coli O157 : H7, a serotype not previously associated with diseases in humans. In Japan, isolates of the serotype O157 : H7 from contaminated drinking water were first implicated in an outbreak occurred in 1990 in a kindergarten of the Saitama Prefecture, and at least other 12 such outbreaks have been recorded in 1993-1995. In the year 1996, unprecedentedly large outbreaks and many sporadic cases of disease caused by E. coli O157 : H7 occurred in various parts of Japan, affecting more than 9000 people in total (11 deaths). In most cases, however, the ultimate source of the infection could not be traced. Although many different serotypes of E. coli, which are collectively referred to as enterohemorrhagic E. coli (EHEC), were found to cause bloody diarrhea, the serotype O157 : H7 has been recognized worldwide as the pathogen associated most frequently with serious complications known as hemolytic colitis and hemolytic uremic syndrome. E. coli O157 : H7 is characteristic of a low infectious dose, on the order of a few hundred organisms, which contributes to the spread of the infection in outbreak situations. Cattle are considered to be the major reservoir of EHEC including O157 : H7. EHEC strains produce at least two immunologically distinct cytotoxins that closely resemble the Shiga toxin produced by the Shigella dysenteriae type 1 strains. These toxins (called Shiga-like toxins or Vero toxins) appear to be responsible for causing many pathological effects associated with EHEC infections. However, how the toxins move from the intestinal tract lumen to the sites where they damage the kidney remains to be evaluated. Moreover, there are some doubts about the value of antibiotic therapy in such infections because of the observation that some antibiotics can increase the toxin expression in vitro and because of the concern that EHEC which are lysing due to their actions in the gastrointestinal tract lumen may actually release more toxin than do intact bacterial cells. Unique biochemical characteristics of E. coli O157 : H7-it ferments sorbitol very slowly and usually does not make β-glucuronidase- are used to differentiate this strain from other enteric E. coli strains. Alternative methods based on the detection of the toxins themselves by enzyme immunoassay are employed in parallel. This review describes the current understanding of the infectious disease caused by E. coli O157 : H7, with an emphasis on the main diagnostic tests and epidemiology for this serotype and the role of the toxins in pathogenesis.

抄録全体を表示

Internal and external methamphetamine (MA) was detected from human hair using ion mobility spectrometry (IMS). Direct IMS monitoring without any sample preparation proved to be effective only to detect MA from externally contaminated hair. The detection limit of external MA was 0.5 ng/mg by direct IMS monitoring when the sample amount was 1.0 mg. To detect MA incorporated in the hair, the authors measured MA users' hair samples by IMS after pulverization or digestion. Pulverized samples gave only moderate sensitivity for the detection of MA in the hair. Digestion of the hair sample with 5 M NaOH (methanol-water, 4 : 1) prior to IMS measurement was very effective to identify MA incorporated in the hair, and the drug was semi-quantitatively detected by this method. The detection limit of MA was 0.5 ng/mg with 2.0 mg of hair sample. Using a combination of the digestion method and direct IMS monitoring, the authors were able to distinguish between MA externally contaminating hair and MA incorporated in a user's hair. It was demonstrated using MA users' hair samples that the results obtained by the digestion method were in good agreement with the GC-MS results. Our method was also successfully applied to a limited amount of MA user's hair sample.

抄録全体を表示

There is a possibility that aliphatic ketones are contained in waste from chemical laboratories, painting factories and so on. Therefore, the polluted water must be treated in order to remove them. In this report each 5 mM ketone in the 0.05 M phosphate buffer (pH 7.0) was treated by ozone alone, UV irradiation alone or ozone + UV irradiation, and their degradation pathways were investigated from the decomposition products. Sample ketones were very rapidly decomposed by ozone + UV, and the main pathway was considered to have released a longer side-chain prior to the other shorter chain. Released alkyl chains were oxidized to aldehydes and fatty acids, and they were decomposed according to each decomposition pathway. The other pathway was production of keto acids by oxidation at the terminal methyl group. Ketones themselves were decomposed slowly by ozone alone, but decomposition by UV alone occurred more rapidly than by ozone alone. The reason was considered ketones have UV absorption about 254 nm which is the irradiation wavelength of a low pressure mercury lamp. The ketones having a longer side-chain were decomposed faster than a short side-chain like acetone. But total organic carbon (TOC) removal (%) was lowered in ketones having side-chains of larger carbon numbers.

抄録全体を表示

The effect of dietary fibers on the liver distribution and fecal excretion of polychlorinated dibenzo-p-dioxins (PCDDs) congeners in the causal rice-bran oil of Yusho was examined in male rats. The fibers used were rice-bran fiber, spinach fiber, burdock fiber, cabbage fiber, soybean fiber, Japanese-radish (root) fiber, carrot fiber, corn fiber, Japanese-radish (leaves) fiber, Chinese cabbage fiber, azuki bean fiber and barley fiber. The animals were administered 4 g of each diet containing 0.5 ml of the rice-bran oil and kept on the same fiber for another 5 d. The oil was contaminated with 1, 2, 3, 7, 8-P₅CDD (6.86 ng/ml), 1, 2, 3, 6, 7, 8-H₆CDD (31.4 ng/ml), 1, 2, 3, 7, 8, 9-H₆CDD (22.4 ng/ml) and 1, 2, 3, 4, 6, 7, 8-H₇CDD (121.7 ng/ml). The fecal excretion of 1, 2, 3, 7, 8-P₅CDD in the group fed with rice-bran and spinach fibers were promoted 3.3 and 3.1 times, respectively, than that in the group fed with a non-fiber diet. The excretion of 1, 2, 3, 6, 7, 8-H₆CDD, 1, 2, 3, 7, 8, 9-H₆CDD and 1, 2, 3, 4, 6, 7, 8-H₇CDD were 2.1, 1.9 and 1.6 times higher, respectively, in the groups fed with rice-bran and spinach fibers than that in the group fed with the non-fiber diet. The present results suggest that the dietary fibers are useful agents for the treatment of patients exposed to the lipophilic contaminants.

抄録全体を表示

The present paper presents the liver distribution and fecal excretion of polychlorinated dibenzo-p-dioxins (PCDDs) congeners, such as 1, 2, 3, 7, 8-P₅CDD, 1, 2, 3, 6, 7, 8-H₆CDD, 1, 2, 3, 7, 8, 9-H₆CDD and 1, 2, 3, 4, 6, 7, 8-H₇CDD, in male rats fed with Chlorella, Spirulina and chlorophyllin. The objective of this study is to evaluate the effect on PCDD excretion by the chlorophyllin foods. The rats were given some treatment diets containing 20% Chlorella. 20% Spirulina, 0.2, 2% chlorophyllin, 10% rice-bran fiber or 0.2% chlorophyllin + 10% rice-bran fiber for 5 d. Then, the animals were administered 4 g of each diet containing 0.5 ml of the causal rice-bran oil of Yusho that had occurred in the Southwest part of Japan in 1968 and kept on the same diet for another 5 d. The rice-bran oil contaminated with 1, 2, 3, 7, 8-P₅CDD (6.86 ng/ml), 1, 2, 3, 6, 7, 8-H₆CDD (31.4 ng/ml), 1, 2, 3, 7, 8, 9-H₆CDD (22.4 ng/ml) and 1, 2, 3, 4, 6, 7, 8-H₇CDD (121.7 ng/ml) was used for the animal experiments. PCDD congeners in the feces and liver were analyzed by high resolution gas chromatography-mass spectrometry. The fecal excretion of 1, 2, 3, 7, 8-P₅CDD in the groups fed with Chlorella, Spirulina and 2% chlorophyllin were 7.4, 7.1 and 11.0 times higher (p<0.01), respectively, than that in the control group. Moreover, the fecal excretion of 1, 2, 3, 6, 7, 8-H₆CDD, 1, 2, 3, 7, 8, 9-H₆CDD and 1, 2, 3, 4, 6, 7, 8-H₇CDD in the same groups were 4.4-5.3, 2.7-3.7 and 1.7-2.8 times higher, respectively, than that in the control group. These findings suggest that administration of Chlorella, Spirulina and chlorophyllin is useful as a new approach in the treatment of patients exposed to lipophilic xenobiotics.

抄録全体を表示

To clarify the mechanism of the increase of arachidonic acid concentration in ogonori (red algae ; Gracilaria asiatica) treated with acetic acid, the changes of fatty acid concentrations of the ogonori treated with acetic acid as functions of temperature and time were investigated. The total fatty acid concentration in the ogonori treated with acetic acid, allowed to stand at 80°C for 60 min, was higher than those at 27°C and 37°C. The concentration was higher in the ogonori treated with 4% acetic acid than that with 0.4% acetic acid. Among the fatty acids, polyunsaturated fatty acids, particularly arachidonic acid (AA, 20 : 4) and dihomo-γ-linolenic acid (20 : 3) showed higher values than saturated fatty acids in the ogonori treated with acetic acid. The same results were also obtained in the ogonori treated with formic acid or hydrochloric acid. A significant negative correlation was observed between the pHs of added acids and concentrations of palmitic acid (r=-0.905, p<0.01), or AA (r=-0.921, p<0.01) in the ogonori. The physical appearance of the ogonori treated with the acids was soft and swollen, thus AA could easily be extracted. Also, the AA concentration derived from the ogonori in the stomach might be enhanced when raw ogonori was ingested.

抄録全体を表示

An extraction method of urinary methamphetamine (MA) using non-chlorinated organic solvents such as hydrocarbons was investigated. MA was extracted most effectively from the urine when petroleum ether containing oleic acid was used. The analytical method is constructed by extraction of MA, followed by derivatization to the trifluoroacetate, which was determined by GC-MS using diphenylmethane as an internal standard. Satisfactory results including the analytical method using GC-MS and recovories of MA from the urine sample were obtained.

抄録全体を表示

The dissolution of tetrachloroethylene (PCE) from the gaseous phase containing PCE to water was studied using an experimental apparatus composed of an aluminium box (25×55×22 cm) covered with a vinyl fluoride film. The dissolution of PCE from the gaseous phase to water was investigated in the state of static sitting. The dissolution rate of PCE from the gaseous phase to water 20 min after the onset of contact was calculated from the data on the relationship between the PCE concentration in water and the contact time. When 0.5, 2.0 and 6.0 ml of the standard PCE gas (80 mg/l) were injected into the equipment, the calculated dissolution rate were 5, 18 and 77 ng/min, respectively. It was shown that the dissolution rate of PCE from the gaseous phase to water was influenced by the PCE concentration in the gaseous phase and by the contact surface area of PCE.

抄録全体を表示

2, 3, 3, 3, 2', 3', 3', 3'-Octachlorodipropylether (S-421) is an organochlorine compound frequently used in a house as a synergist for insecticides or as a mothproofing agent for household necessities. Domestic human exposure of S-421 was evaluated by the analyses of S-421 concentration in housedust samples sucked into a vacuum cleaner. S-421 was detected in all 20 samples of the housedust at a level of 0.04 to 15.9 mg/kg. S-421 concentration in the housedust collected from a separate wooden house was generally higher than that from a towering condominium. The average S-421 level analyzed here was approximately four times higher than that reported in 1984 by Uno et al. Application of insecticides for termite control of a house, mothproofing processing of household necessities and/or spraying the aerosol pesticides for domestic use might have elevated the S-421 pollution level in a house.

抄録全体を表示