Lead is a heavy metal which has been experimentally and epidemiologically shown to induce vascular lesions such as atherosclerosis, however, little is known about the mechanism. Since damage of endothelial cell layers is a key event in the initiation of atherosclerosis, the effect of lead on the maintenance of cell layers has been studied using a cell culture system in our laboratory. The following results were obtained : (1) Endothelial cell monolayers are not destroyed but the repair after injury is markedly inhibited by lead through inhibition of the proliferation. (2) Lead suppresses the proliferative response of endothelial cells to basic fibroblast growth factor (bFGF). (3) Lead reduces the amount of endogenous bFGF bound to heparan sulfate proteoglycans through inhibition of the synthesis of perlecan, a large heparan sulfate proteoglycan. Since heparan sulfate chains of perlecan promote the binding of bFGF to its receptor, our results indicate that inhibition of the repair of injured endothelial monolayers by lead is due to a lower proliferative response of the cells to endogenous bFGF, caused by a suppression of perlecan synthesis.
Air samples were collected at the sides of busy traffic roads in downtown Kanazawa, Sapporo and Tokyo during the same periods both in the daytime and in the night, in winter and summer. We determined the levels of polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs), which are known to be carcinogenic and/or mutagenic. PAHs and NPAHs were analyzed simultaneously with an HPLC system with fluorescence detection for PAHs and another HPLC system with chemiluminescence detection for NPAHs, respectively. The amounts of airborne particulates were larger in the daytime than in the night in all three cities. This result was thought to reflect the diurnal change of such urban activities as traffic volume. Many of the PAH and NPAH compounds showed higher concentrations in the daytime than in the night, and also showed higher concentrations in winter than in summer in the three cities. This result coincided with the trends observed in our continuous surveys in downtown Kanazawa for several years. However, 5-ring PAHs, such as benzo [a] pyrene, and dinitropyrenes in Tokyo did not show such diurnal or seasonal differences. The composition ratio of NPAHs and the contribution of diesel-engine vehicles to the atmospheric concentrations of NPAHs were calculated from all the data of this survey. The concentration ratio of dinitropyrenes to 1-nitropyrene became larger with an increase in the ratio of diesel-engine vehicles to the total vehicles registered, suggesting a large contribution of diesel-engine vehicles to the concentrations of these NPAHs in urban air.
An HPLC method using post-column Simon's reaction (SR-HPLC) for the determination of methamphetamine (MA) has been developed. The detection limit was 1ng, which is about 100 times more sensitive than TLC using Simon's reaction (SR-TLC). The calibration curve was linear in the range of 0.1-1000μg/ml, and the intermediate precision of within-run and between-run assays was 1.15% and 2.12%, respectively. MA in 13 urine samples was determined by SR-HPLC and GC with flame ionization detection, and these quantitative values were strongly correlated (r2=0.995). MA could be analyzed without interference peaks. The proposed method is highly selective and quantitative.
Tetrachloroethylene (PCE) and 1, 1, 1-trichloroethane (1, 1, 1-TCA) were administered intraperitoneally at a moderately toxic dose of 1 g/kg/d for three consecutive days to male and female Wistar rats weighing about 200g (7 weeks old). The agents were given alone or simultaneously with phenobarbital (PB, 80mg/kg/d) and the animals were sacrificed 24h after the last treatment. Microsomal fractions prepared from both lungs and livers were tested for the monooxygenase activity and protein content of four cytochrome P450 (CYP) isoforms, i.e., CYP1A, 2B, 2E1 and 3A. As far as the monooxygenase activity was concerned, CYP1A, 2E1 and 3A but not 2B were constitutive in liver while only CYP2B was detected in lung. PCE suppressed significantly pulmonary CYP2B and hepatic CYP2E1 but enhanced hepatic CYP1A. In contrast, 1, 1, 1-TCA suppressed hepatic CYP2E1 under the conditions used. Although PB induced hepatic CYP2B and enhanced CYP1A several-fold, it had no effect on CYP2E1 and 3A, as well as pulmonary CYP2B. The effects of PCE and 1, 1, 1-TCE on CYP isoforms in microsomal fractions prepared from PB-cotreated animals were also studied comparatively in terms of sex and organ. The response of pulmonary enzymes to both chemicals was the same as that of PB-untreated animals. As far as PB-induced hepatic CYP2B was concerned, PCE was suppressive while 1, 1, 1-TCA showed a degree of potentiation. Furthermore, in the case of CYP1A a sex difference was noted in the response to these chemicals. As far as the protein levels of CYP isoforms were concerned, they were generally proportional to the enzyme activities.
We investigated the desmutagenic action of extracts from Smilax rhizome, Mulberry bark and Berchemia racemosa on Trp-P-1 and Trp-P-2 by means of spore rec-assay. The results obtained are as follows : (1) 50% ethanol and ethanol extracts from each crude drug showed desmutagenic action on Trp-P-1 and Trp-P-2. (2) Most of the desmutagenic activity in 50% ethanol extract from each crude drug was due to an ethyl acetate soluble fraction. (3) The interaction between the ethyl acetate soluble fraction from each crude drug and Trp-P-1 was much stronger in Mulberry bark and Berchemia racemosa than in Smilax rhizome.
Reaction of fragrant 4-hydroxy-3(2H)-furanones including 2, 5-dimethyl-4 hydroxy-3(2H)-furanone (DMHF) and 4-hydroxy-2-(or 5)-ethyl-5-(or 2)-methyl 3(2H)-furanone (HEMF) present in many processed foods with nitrous acid was studied. It was found that DMHF or HEMF swiftly reacted with nitrous acid at a molar ratio of 2 : 1 at pH 3 and 37°C. The products from the reaction of DMHF or HEMF with 4 equivalents of nitrous acid in chloroform were analyzed. Elemental analysis of the unpurified products showed that nitrogen atoms were introduced into the products which were found to be composed of multiple unstable furanone ring-opened compounds. The DNA-breaking and reducing activity of parent DMHF and HEMF were lowered by the nitrous acid treatment. The unpurified products were weakly mutagenic to a Salmonella typhimurium TA100 strain without metabolic activation. It was found that DMHF and HEMF effectively scavenged nitrous acid accompanied by concomitant loss of DNA-breaking activity and formation of compounds with relatively weak mutagenicity.
Amlodipine besylate, a dihydropyridine calcium antagonist, was evaluated for its potential to cause embryonal fetal toxicity and teratogenicity in pregnant mice. Amlodipine was administered in drinking fluid at dose levels of 0.2, 0.8 and 1.6mg/kg body weight on days 1 through 21 of gestation. Litters were examined on gestational day 21. There were significant (p<0.05) decreases in the absolute and relative weights of the maternal heart, liver, pancreas and vagina in the 0.8 and 1.6mg/kg body weight amlodipine, and non-significant decreases in these measurements in the 0.2mg/kg body weight dose level. There was no fetal growth retardation as shown by the crown rump length in the 0.2 and 0.8mg/kg body weight amlodipine. At dose size of 1.6mg/kg body weight, amlodipine caused embryo lethality. The no-observed-adverse-effect level (NOAEL) was found to be 0.2mg/kg amlodipine.
An investigation of the metal concentrations of potassium, sodium, calcium, magnesium, copper, zinc, manganese and iron in the black and gray hairs of the same person in Taiwan was performed using atomic absorption spectroscopy (AAS). The flame modus of AAS was employed to determine the concentrations of trace and mineral elements. The results of trace element and mineral element concentration determinations were evaluated by statistical analysis using the t-test for comparison of significant differences between black and gray hairs of the same person in the same region of the head. Our findings revealed that the concentrations of potassium, sodium, calcium, magnesium, copper, zinc, manganese and iron in gray hairs were lower than those in black hairs. Concentrations of manganese, copper, magnesium, calcium and sodium showed significant differences between the two kinds of hairs (p<0.05). On the contrary, no significant differences were noted in zinc, iron, and potassium (p>0.05). Our experiment gives direct evidence to suggest that reduction of hair trace element and mineral element concentrations may be one of the factors associated with hair graying or aging. Manganese, copper, magnesium, calcium and sodium obviously have greater effects on the hair color and aging.
Solid-phase extraction cartridges, Silica, Florisil, ethylenediamine-N-propylsilane-bonded silica (PSA), trimethylaminopropylsilane-bonded silica (SAX) and graphitized nonporous carbon (ENVI-Carb) were investigated for cleanup of pesticides residues suspected as endocrine disruptors in food extracts. Elution patterns and recoveries were examined for 38 pesticides with 2 types of eluting solvents : acetone/n-hexane and diethyl ether/n-hexane. A 2% acetone-n-hexane eluant used with the Silica cartridge gave the best recovery for 33 pesticides and minimized interference from coextractants. The remaining 5 pesticides were eluted successively with 20% acetone-n-hexane from tandem connected Silica and PSA cartridges. Thirty-eight pesticides were analyzed in 30 duplicate meals with the limits of detection ranging from 0.01 to 0.5ppb. trans-Chlordane, trans-nonachlor and p, p'-dichlorodiphenyldichloroethylene (p, p'-DDE) were found frequently (Tr.-1.1ppb). Dietary daily intakes were 0.27μg/d for total chlordane, 0.85μg/d for total dichlorodiphenyltrichloroethane (DDT), which were significantly below the acceptable daily intake (ADI) values.
Natural colorants are widely used as additives to various foods. However, the basic data concerning the safety of these colorants are insufficient. Seven natural food colorants were assessed for their hepato- and nephrotoxicity in mice depleted of glutathione by pretreatment with buthionine sulfoximine (BSO). Oral administration of red cabbage color (4500mg/kg), gardenia yellow (4500mg/kg), cochineal extract (3000mg/kg), beet red (6000mg/kg), carthamus yellow (6000mg/kg), purple corn color (4500mg/kg), and lac color (1400mg/kg) to mice in combination with BSO (4mmol/kg, i.p.) produced no significant changes in serum glutamic pyruvic transaminase (SGPT) activity and serum urea nitrogen (SUN) concentration, although eugenol as the positive control for hepatotoxicity and thiabendazole as the positive control for nephrotoxicity produced significant increases in SGPT activity and SUN concentration, respectively.
Balance, excretion and tissue distribution of vanadium in rats were investigated. Female Wistar strain rats, weighing 110-120g (approximately 5 weeks old), were divided into a normal control group and a vanadium exposed group, of seven animals each. Vanadium exposed animals were fed the control diet plus sodium metavanadate (V5+) at concentrations of 100ppm for 7 days. Relatively high concentrations of vanadium were found in bone, spleen, kidney and liver in the vanadium exposed group, with the highest concentration found in bone. The percentages of vanadium excreted in the urine and feces were 0.86 and 83.5% of the intake, respectively. Thus, the retention rate was 15.7%. The data suggests that feces are the major route of excretion, and that vanadium is poorly absorbed by the intestinal tract.
A total of 120 strains of Vibrio mimicus, 51 clinical and 69 environmental, were examined for the presence of three types of hemolysin genes (vmh, tdh and hlx) by PCR. Ninety-six percent (115) of the strains contained at least one of these hemolysin genes. Only 5 strains from the environment were missing all three hemolysin genes. The tdh was only found in 20 of the 51 clinical isolates of V. mimicus. This may indicate that the tdh gene is a virulence determinant of V. mimicus. More than 90% of the strains isolated from both the environment and patients possessed the vmh gene. Two clinical isolates possessed the hlx gene alone and had no other enterotoxic factors.
This study demonstrates the reduction of N-hydroxy-2-acetylaminofluorene (N-OH-AAF) to 2-acetylaminofluorene by heme in the presence of hydroquinones. N-OH-AAF was reduced by hemoglobin and hematin in the presence of menadiol or 1, 4-dihydroxynaphthalene under anaerobic conditions. However, protoporphyrin, ferric chloride and ferrous chloride did not catalyze the reduction of N-OH-AAF, even in the presence of hydroquinones. N-OH-AAF was also reduced by liver microsomes and cytosol, and by rat blood in the presence of 1, 4-dihydroxynaphthalene. When liver preparations and blood were boiled, these activities were not diminished. The reduction is considered to occur nonenzymatically at the heme group of catalytic hemoproteins in the presence of hydroquinones as an electron donor.
The effect of experimental diets with fermented soybean (natto) containing soybean extract (nijiru) on ovariectomy (OVX)-induced bone loss was investigated. Experimental diets containing either natto (46%), natto with 3.8% nijiru supplementation or natto with 9.8% nijiru were freely given to sham-operated rats or OVX rats for 3 months. Nijiru contained saponin (660μg/g of dry nijiru) and isoflavone including daidzin (770μg/g) and genistin (580μg/g) of comparatively higher concentration. OVX caused a significant reduction in the dry weight, mineral density and mineral content of the femur. The calcium content in the femoral-metaphyseal tissues was significantly reduced by OVX and these reductions were largely prevented by the feeding of natto diets with nijiru (9.8%) supplementation. This study demonstrates that the intake of natto diets supplemented with nijiru containing isoflavone and saponin has a preventive effect on OVX-induced bone loss, suggesting that it may have a role in the prevention of osteoporosis.
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