We used the capture-recapture method to estimate the population size of injecting drug users (IDU). We collected and analyzed registry data from the Drug Use Rehabilitation Center in Leshan Downtown District, designed the interval between capture phase and recapture phase, explored the data model of the capture-recapture method (CR), and estimated the size of a local IDU population. The estimated size was 3455. Establishment of a consistent data model played a key role in estimating the IDU population size using CR. CR is an easy-to-use and inexpensive technique for IDU population size estimation, which generates reliable results.

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To clarify the relationship between heat shock protein (Hsp) 70 expression and dioxin toxicity, we studied the effect of quercetin, which is an inhibitor of the biosynthesis of Hsp70, on the acute toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in C57BL/6J mice. Contrary to our expectation, results showed that continuous administration of quercetin could attenuate the reduction in body weight gain produced by TCDD (100 μg/kg, p.o.). In addition, the hepatomegaly was also significantly reduced by treatment with quercetin for 1 and 30 day(s) after TCDD treatment in spite of having no effect on thymic atrophy. On the other hand, quercetin showed no notable effects on TCDD-induced changes in hepatic Hsp70.1 mRNA, ethoxyresorufin O-deethylase activity and lipid peroxidation. Although we failed to clarify the exact protective mechanisms, our data suggest that quercetin has a protective effect against some forms of dioxin toxicity.

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We attempted to further define the effects of an Mg-deficient diet on blood pressure in rats fed Cd for long periods. Twenty male Wistar rats were grouped according to four different diets: normal diet (N rats); normal diet supplemented with Cd at a dose of 50 μg/g of diet (N rats fed Cd); Mg-deficient diet (D rats); and Mg-deficient diet supplemented with Cd at a dose of 50 μg/g of diet (D rats fed Cd). Each diet was given for 60 days. N rats fed Cd developed a duration-limited increase in blood pressure: by day 60, increased blood pressure returned to the level seen in N rats. Mg deficiency lowered the Cd-induced increase in blood pressure and this response was more pronounced on day 60. A variety of independent blood pressure regulatory mechanisms was investigated. Although Mg deficiency tended to occur at lower concentrations of Cd and metallothionein in the heart of N rats fed Cd and the Cd concentration was less than 5 μg/g of tissue, Mg deficiency increased the Ca concentration in the hearts of N rats fed Cd while a decrease in urinary Na excretion and an increase in water retention were not observed. Diet-related toxic clinical signs in D rats fed Cd induced marked blush on the ears and fingers, indicating vasodilatation had occurred. These findings may have been a factor in the pronounced reduction in blood pressure seen.

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The protective effect of Spirulina fusiformis extract against mercury toxicity studied in Swiss albino mice. Animals treated with HgCl₂ (5.0 mg/kg b.wt. i.p.) showed a significant elevation in lipid peroxidation level (LPO), aspartate amino transferase (AST) and alanine amino transferase (ALT) activity. However, a marked decline in serum alkaline phosphatase activity and reduced glutathione (GSH) content was recorded. Whereas, animals treated with Spirulina fusiformis extract (800 mg/kg b.wt. orally) before and after mercury intoxication showed a significant decrease in LPO level, AST and ALT activity and increase in serum alkaline phosphatase activity and GSH content. Spirulina fusiformis alone treatment did not alter reduced glutathione, AST, ALT and alkaline phosphatase activity but significantly diminishes the LPO level. Thus, the results obtained from the present study suggest that oral administration of Spirulina fusiformis extract provides protection against mercuric chloride induced toxicity in Swiss albino mice.

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The present study was carried out to elucidate the effect of a moderately Mg-deficient diet on circulation parameters such as blood pressure and cardiac functions in rats treated with Cd. Forty male Wistar rats were divided into the following groups to evaluate the effect of two different dietary Mg concentrations in regard to Cd treatment: normal dietary Mg and no Cd treatment (group N); normal Mg plus Cd treatment (group N + Cd); moderately Mg-deficient diet defined as 40% concentration of normal level and no Cd treatment (group D); and moderate Mg-deficient diet plus Cd treatment (group D + Cd). Subcutaneous injection of Cd in the backs of the animals at 1 mg/kg body weight was performed twice a day for 7 consecutive days and the animals then were maintained with two different diets and without Cd treatment for an additional period of 203 days before analysis. Comparison of the two groups of N + Cd and D + Cd showed that ingestion of the Mg-deficient diet markedly increased cardiac output and decreased total peripheral resistance without altering blood pressure. The Ca concentration in the heart of D + Cd rats was not increased compared with that from N rats, although there was significant interaction between Mg deficiency and Cd treatment on the Ca concentration in the heart, suggesting that moderate Mg deficiency did not cause myocardial necrosis or impair cardiac contraction in the rats treated with Cd.

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In this study, the characteristics of polycyclic aromatic hydrocarbons (PAHs) in airborne particles equal to or less than 10 μm (PM10), collected from the Bangkok urban air, were investigated. Sixteen PAHs content in PM10 were simultaneously measured. High molecular weight PAHs (four-, five-, and six-ring) were more abundant in airborne particles (91.7% of total PAHs) than those of low molecular weight PAHs (two-, and three-ring). Further, 71.4% of the total PAHs found in the study sites are potentially carcinogenic PAHs. Benzo[a]pyrene (BaP) was a prominent carcinogenic compound for PAH mixtures found in the area. Correlation analysis revealed that there is a close correlation between the concentration of carcinogenic PAHs and amount of PM10. This is due to their absorptivity property on the surface of the particles. In this study the lifetime lung cancer risk was estimated from the seven carcinogenic PAHs using the toxicity equivalent factor (TEF). The probable number of lung cancer cases in Bangkok Metropolitan was estimated at 27 cases/year. The concentration of carcinogenic PAHs found in Bangkok city in 2002/2003 is comparable to values in many other cities.

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Contribution of glucuronic acid and sulfonic acid moieties during the photocatalytic degradation of estrogen conjugates, one of the endocrine disrupting chemicals, has been investigated. Estrogens were subjected to photocatalytic degradation using titanium dioxide immobilized on glass beads as a catalyst, whose time courses were measured by HPLC or liquid chromatography (LC)/MS/(MS). Estradiol and estrone, which have an unconjugated phenolic hydroxy group at the C-3 position, were gradually degraded by UV irradiation and nearly disappeared within 6 hr. 3-Desoxyestradiol, which does not have a phenolic hydroxy group at C-3 position, was also degraded like estradiol. The corresponding 17- or 3-glucuronide was degraded faster than the respective genin, estradiol or estrone. The double conjugate, estriol 3-sulfate 16-glucuronide, was also easily degraded within 3 hr. On the other hand, the degradation of estrogen 3-sulfate did not start within 2.5 hr but the reaction was completed within 6 hr. These data showed that the glucuronic acid moiety on the estrogen skeleton and sulfonic acid moiety at phenolic hydroxy group play an important role for this degradation reaction.

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Screening and quantitative analysis for six sulfonylurea-type oral antidiabetic agents (SU-OADs), tolbutamide (TOL), acetohexamide (ACE), chlorpropamide (CHL), gliclazide (GLC), glibenclamide (GLB), and glimepiride (GLM), in adulterated health food has been developed. The SU-OADs were extracted with acetone and then the extract was subjected to thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). In the TLC analysis, good separation was achieved with a mixture of n-butyl acetate containing 0.4% formic acid as a solvent. Ultraviolet irradiation at 254 nm was used to detect the SU-OADs. Specificity was obtained with Dragendorff's test solution, 10% phosphomolybdic acid methanol solution, and 30% sulfuric acid methanol solution. On the other hand, with a gradient reverse-phase HPLC system equipped with a photodiode array detector, we were able to detect the SU-OADs within 15 min using an ODS column and acetonitrile-ammonium acetate buffer as a mobile phase. Quantitative analysis based on HPLC was also performed with the absolute calibration curve method. Recoveries were 90.7-105.2% for the drugs tested. The intra- and interassay relative standard deviations were 0.2-8.1 and 0.6-7.2%, respectively. When the methods were applied to prescription glibenclamide tablets, health food, and spiked samples, good selectivity, separation, recovery, and precision were obtained.

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Several epidemiological and experimental studies have demonstrated that exposure to arsenic is associated with vascular disease such as atherosclerosis. Since vessel proteoglycans (PGs) are key molecules in the progression of the vascular lesion, we investigated the effect of arsenic on the synthesis of PGs in cultured bovine aortic endothelial cells. The results indicate that sodium arsenite (NaAsO₂) significantly decreases the accumulation of both heparan sulfate PGs and chondroitin/dermatan sulfate PGs in the cell layer and the conditioned medium of the cells without nonspecific cell damage and inhibition of whole protein synthesis. While sodium arsenate (Na₂HAsO₄) did not influence PG synthesis, arsenic trioxide (As₂O₃) inhibited PG synthesis as a result of nonspecific cell damage. The present data suggest that arsenite may contribute to the progression of atherosclerosis through inhibition of PG synthesis in vascular endothelial cells.

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The aim of this study was to develop phylogenetic oligonucleotide probes for screening common foodborne bacteria. Twenty oligonucleotide probes were designed by aligning representative 16S ribosomal DNA (rDNA) sequences from 64 species of common foodborne bacteria and other bacteria. To confirm the specificity of each probe simultaneously, a DNA microarray that the 20 probes were immobilized on a glass slide was prepared. RNAs extracted from 13 species of foodborne bacteria were fluorescently labeled and hybridized on the DNA microarray. The 16S rRNAs showed a unique hybridization pattern in combination with the designed oligonucleotide probes, leading to 16S rDNA phylogenetic analysis of their sequences. Probe EC001 for Escherichia coli spp. and Shigella spp., probe SSP003-L for Salmonella enterica subsp. enterica serovar Enteritidis and Salmonella enterica subsp. enterica serovar Typhimurium, probe YE002 for Yersinia enterocolitica and probe BC001 for Bacillus cereus group were particularly useful for screening these foodborne bacteria. DNA microarray is useful as a procedure for evaluating the multiple designed probes. The selected probes can be readily applied to screening of foodborne bacteria using hybridization methods, such as fluorescent in situ hybridization (FISH), bead array hybridization and so on.

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We examined the relation between sudden infant death syndrome (SIDS) mortality and meteorological factors, specifically ambient temperature, sunshine duration, and atmospheric pressure, in Japan. Using both the data of daily SIDS mortality and meteorological factors for the years 1972 through 1995, we calculated the Mantel-Haenszel rate ratios of SIDS, controlling for selected covariates. We found an inverse association of SIDS mortality rate with daily mean temperature and daily mean sunshine duration. In conclusion, although this was an exploratory study, further investigation of the relation between SIDS and meteorological factors appears to be warranted.

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Among cannabinoids (CNs) in two commercially available and long-term stored cannabis oils obtained from the seeds of Cannabis sativa L. in Japan, tetrahydrocannabinol (THC), canabidiol (CBD), cannabinol (CBN), and cannabichromene were identified and determined using high-performance thin-layer chromatography and capillary gas chromatography-mass speectrometry after partitioning extraction with n-hexane/acetonitrile. CNs were determined in two commercially available cannabis oils, designated “Hemp oil” (THC, 16.3 μg/g and CBN, 5.9 μg/g) and “Taima-yu” (CBD, 26.1 μg/g). The concentration of CBD in a cannabis oil that had been stored for 20 years was 107 ± 4 μg/g. However, no other CNs including THC were detected in the oil. The CBD content in the original oil was estimated to be about 130 μg/g from the determination values of the two periods. These results suggest that cannabis oils generally contain CNs to some extent.

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Hydroxylated polychlorinated biphenyl (OH-PCB) is a major metabolite of PCB, which is an endocrine disruptor. In this study, we investigated the neurobehavioral effects of prenatal exposure to a very low dose of OH-PCB (4-hydroxy-2′, 3, 3′, 4′, 5′-pentachlorobiphenyl, 4-OH-pentaCB) in mice. 4-OH-pentaCB, dissolved in corn oil, was orally given at 0.1 μg/30 μl/animal/day to pregnant mice from gestation days 11 to 17. In the open field test, the number of ambulation and rearing drastically increased among 4-OH-pentaCB exposed mice compared with the control. However, 4-OH-pentaCB exposure had no effect on passive avoidance. These results suggest that an extremely low dose of 4-OH-pentaCB may selectively disrupt neurobehavioral functions involved in ambulation and rearing in mice.

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The antioxidative activities of 3-O-octanoyl-(+)-catechin were studied in vitro. Free radical scavenging activities were tested by spectrophotometrically measuring 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonate) (ABTS) radical cations, as well as by measuring luminol chemiluminescence induced by peroxyl radicals generated from 2,2′-azinobis(2-amidinopropane) dihydrochloride (AAPH). The radical scavenging activities of the 3-O-octanoyl-(+)-catechin for ABTS radical cations and peroxyl radicals were less effective than the original (+)-catechin, but stronger than 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid (Trolox). Furthermore, 3-O-octanoyl-(+)-catechin unlike (+)-catechin did not effectively antagonize the decrease in the intrinsic fluorescence intensity of allophycocyanin induced by AAPH, which was measured as an index of protein damage. Conversely, 3-O-octanoyl-(+)-catechin demonstrated more potent antioxidative activity for the linoleic acid peroxidation induced by AAPH than (+)-catechin and Trolox. These findings suggest that the introduction of an octanoyl group at the 3-OH position in a (+)-catechin effectively quench the secondary products of lipid peroxidation without much loss of free radical scavenging activity.

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Metallothionein (MT) is endowed with strong antioxidant and nucleophilic properties and is found not only in the cytosol but also in the nucleus. To investigate whether MT can directly protect against oxidative DNA damage in the nucleus, the effect of MT on 8-hydroxy-2′-deoxyguanosine (8-OHdG) formation induced by ferric nitrilotriacetate (Fe-NTA) was studied using purified MT or the primary cultures of MT-enriched hepatocytes. The level of 8-OHdG was increased in a dose-dependent fashion by incubation of salmon sperm DNA with Fe-NTA in the presence of hydrogen peroxide. Addition of purified MT at 12.5 μM to its incubation mixture resulted in a decrease of the 8-OHdG content in DNA by approximately 50%. In the primary cultures of control hepatocytes, treatment of Fe-NTA at 200 μM resulted in significant decreases in cell survival and an increased in the concentration of 8-OHdG following depletion of glutathione. However, these toxic effects of Fe-NTA were modulated in MT-enriched cells. These results suggest that MT may protect DNA against radical attack as a cellular radical scavenger.

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Rabeprazole sodium (rabeprazole), a proton pump inhibitor (PPI), is widely used in the treatment of peptic ulcer and gastroesophageal reflux disease. Recently, some antiulcer medicines have been elucidated pharmacologically from the viewpoint of gut-regulated hormone levels. We examined the effects of rabeprazole on plasma levels of gastrointestinal peptides [gastrin, somatostatin, motilin, substance P, and calcitonin gene-related peptide (CGRP)]. Rabeprazole at a dose of 20 mg or placebo was orally administered to 5 healthy male volunteers aged 25-30 years. Venous blood samples were taken before and 30, 60, 90, 120, 180, 240, and 360 min after administration. Plasma peptide levels were measured using a sensitive enzyme immunoassay. Compared with the response of the placebo group, rabeprazole caused significant (p < 0.05) increases in gastrin-, somatostatin-, and CGRP-like immunoreactive substance (IS) at 360, 180, and 240 min, respectively. Rabeprazole significantly decreased motilin-IS levels at 180 min compared with the placebo group. However, rabeprazole had no effect on plasma substance P-IS levels. Although rabeprazole has potent antisecretry effects, the agent may have little effect on gastrointestinal peptides.

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Heparin has various actions in animal tissues, but the action mechanisms have not been fully elucidated. Here, we have investigated the stimulatory increase in the leukotriene (LT) B₄ content of rat hepatocytes induced by heparin. Heparin increased the LTB₄ content of the hepatocytes in a time-dependent manner up to 5 min; its maximal effect was three-fold higher than the basal level of LTB₄. When tyrosine kinase (TK) activity in the membrane-containing preparation of the hepatocytes was suppressed, the stimulatory increase in LTB₄ by heparin was markedly reduced. It was also observed that the heparin-stimulated increase in LTB₄ was reduced by various cytosolic phospholipase A₂ (PLA₂) inhibitors. These findings suggest that heparin stimulates a rapid increase in LTB₄ in rat hepatocytes, and that this increase is partly due to an action involving the membrane TK- and the cytosolic PLA₂-sensitive pathways.

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1,4-Dioxane is a newly added compound to the water quality standards in Japan that were revised in 2003. In order to estimate the contribution of 1,4-dioxane in drinking water to the total exposure in humans, it is necessary to take into account the quantity of the compound in food. In an earlier study, we measured the intake of 1,4-dioxane in food based on the average consumption of food in the Kanto area.¹⁾ The total daily intake of 1,4-dioxane was calculated to be 0.440 μg. In the present study, we investigated the intake of 1,4-dioxane from food by sampling meals from 3 days from 3 homes in 9 prefectures, respectively. 1,4-Dioxane was extracted from 20 g of homogenates of mixed meals using the steam distillation, concentrated by a solid phase cartridge and then measured using gas-chromatography/mass spectrometry. The detection limit of the analysis was 2 μg/kg. No 1,4-dioxane was detected in 26 samples, while 3 μg/kg was detected in one sample. In this sample case, the daily intake of the 1,4-dioxane was calculated as 4.5 μg that represented 0.56% of the total daily intake (TDI) (4.5 μg/{16 μg/kg body weight/day × 50 kg}).

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