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Chlorinated benz[ a]anthracenes (Cl-BaA) are halogenated aromatic compounds (typified by dioxins) found in the environment at relatively high concentrations. Fischer 344 rats were intragastrically administered 0, 1, or 10 mg of Cl-BaA or its parent compound benz[ a]anthracene (BaA) per kg of body weight for 14 consecutive days. Both chemicals at 10 mg/kg/day inhibited the gain in body weight, and consequent increase in relative liver weight. Hepatic gene expression of cytochrome P450 (CYP) 1A1, 1A2, and 1B1 was significantly stimulated by administration of BaA (10 mg/kg/day) compared with the control. After administration of Cl-BaA, only the CYP1A2 gene was significantly induced, even at the lower dosage; CYP1A1 and 1B1 mRNA levels remained unchanged in Cl-BaA-treated rats compared with controls. To elucidate the role of such Cl-BaA exposure and induced CYPs at toxicity onset, we investigated the mutagenicity of BaA and Cl-BaA using Salmonella typhimurium TA98 and TA100. BaA and Cl-BaA at 10 μg/plate produced positive results in both strains in the presence of rat S-9. Incubation of Cl-BaA with recombinant rat CYP1A2 produced a significantly higher number of revertant colonies in TA98 and TA100 than in controls, but no such change was observed for BaA. In conclusion, BaA changes its own physiological and toxicological actions by its chlorination; (1) daily exposure to Cl-BaA selectively induces hepatic CYP1A2 in rats and (2) Cl-BaA induces frameshift mutations in the presence of CYP1A2, although BaA does not exert mutagenicity. This indicates that CYP1A2 may metabolize Cl-BaA to active forms. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2013. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the tensile bond strength (TBS) to peroxide-exposed dentin. Furthermore, the effect of ascorbic acid (AA) on the bond strength of peroxide-exposed dentin was investigated. Extracted bovine dentin was exposed to 10% carbamide peroxide, 30% hydrogen peroxide, or distilled water for 30 min, then treated with 10% AA (0, 30, 90, and 180 min), and conditioned with 10% citric acid/3% ferric chloride. The polymethyl-methacrylate (PMMA) rod was bonded to the treated bovine dentin with 4-META/MMA-TBB resin. A minidumbbell-shaped bonded specimen was prepared from these bonded assemblies and the TBS was tested. The fractured surfaces were also observed with a scanning electron microscope. Exposure to peroxide before bonding significantly reduced bond strength. The application of AA to the peroxide-exposed dentin increased bond strength. On the other hand, an adverse effect of AA was found in distilled water-affected dentin. Extended resin fibers were partially seen in the peroxide-exposed dentin. In conclusion, peroxide reduced the bond strength, and the stronger the oxidation, the weaker the obtained bond. Antioxidation with AA recovered the bond strength, and this effect increased the longer the AA was applied. [ABSTRACT FROM AUTHOR]

Summary The purpose of this study was to evaluate the priming effect of 2-hydroxyethylmetaclirate (HEMA) following acid treatment on resin bonding to prototype Er:YAG laser-irradiated dentine. Extracted bovine dentine following laser irradiation was acid treated by aqueous solution of 10% citric acid (10-0) or 10% citric acid/3% ferric chloride (10-3), and additionally treated with 35% HEMA. Pre-treated dentines were bonded to the polymethyl-methacrylate (PMMA) rod with 4-META/MMA-TBB resin (Super Bond C & B) and miniaturized dumbbell-shaped bonded specimens were prepared. These specimens profiled for tensile bond testing and fractured surfaces were observed by scanning electron microscopy (SEM). Cross-sections of resin–dentine interface were also examined. The HEMA treatment following acid conditioned by 10-3 or 10-0 for both laser-irradiated and non-irradiated dentines was significantly higher than that without HEMA treatment. SEM view of a fractured specimen showed some cohesive failure in cured resin, but almost all of the fractured surface shows boundary failure between the penetrated resin and underlying dentine. A cross-sectional view of the interface showed a very thick hybrid layer between the hybridized dentine and underlying dentine. It was concluded that HEMA treatment following acid conditioning provided a slightly higher bond strength for both the Er:YAG laser-irradiated and non-irradiated dentines. However, the bond strength of Er:YAG laser irradiated dentine was significantly lower than that of the non-irradiated dentine. [ABSTRACT FROM AUTHOR]

Background: The trimethadione (TMO) tolerance test was performed to evaluate its usefulness in the assessment of hepatic functional reserve in patients with biliary atresia. Method: Nineteen patients with biliary atresia after hepatic portoenterostomy (age range: 2 months to 25 years; sex: 6 males and 13 females) were studied. The study was performed in the morning after a 12-h fast. TMO was given orally, at a dose of 4 mg/kg, with 5 mL of 5% glucose 2 h before breakfast. Blood samples (0·5 mL) were collected to determine serum TMO and dimethadione (DMO), a metabolite of TMO, levels 4 h after the administration of TMO. TMO and DMO were measured by a gas-liquid chromatographic method. Results: A higher total bilirubin level (over 1 mg/dL) in patients with jaundice was reflected in the smaller serum DMO/TMO ratio 4 h after the oral administration of TMO. In addition, these patients with total bilirubin levels of 1 mg/dL or less had a significantly lower DMO/TMO ratio than the control group (healthy subjects). The serum DMO/TMO ratio showed a close correlation with the Child–Pugh score, which is used for overall evaluation of severity of cirrhosis and Mayo risk scores for primary biliary cirrhosis in adults (0·856, P < 0·01 and 0·788, P < 0·01, respectively). The TMO tolerance test shows the benefit of performing a relatively early test of dynamic liver function to evaluate hepatic functional reserve in pre- and post-operative biliary atresia patients. [ABSTRACT FROM AUTHOR]

Adult normal mice and those mice which had been thymectomized, X-irradiated, and reconstituted either with bone marrow cells and thymus cells (TxXBT) or with bone marrow cells alone (TxXB), were given varying amounts (0.1-5 mg) of deaggregated soluble bovine serum albumin (sBSA). They were challenged 10 days later with an immunogenic form of BSA. TxXB mice were supplemented with normal thymus cells 3 days before the challenge. With any dose of sBSA, TxXBT and normal mice were made tolerant. Only 5 mg of sBSA, the highest dose in these experiments, was effective in inducing the tolerance in TxXB mice. The simultaneous administration of 5 mg of sBSA and 0.1 mg of alumprecipitated BSA plus 0.01 mg of endotoxin resulted in the priming in TxXBT mice but induced tolerance in TxXB mice. These results indicate that: (a) B-cell tolerance could be induced independently of the influence of T cells; (b) the tolerogen susceptibility of B cells may be lower than that oft cells; (c) such a weakly immunogenic agent as the mixture of tolerogen and immunogen could either activate the antibody response in the presence oft cells or induce B-cell tolerance in the absence of T cells. [ABSTRACT FROM AUTHOR]

We examined the effects of cyclosporin A (CsA) administered in vivo on the capacity of peripheral blood mononuclear cells (PBMC) from kidney transplant recipients to express IL-2 receptor (IL-2R) gene at the level of mRNA after mitogen stimulation in vitro. There were no differences in the percentage of IL-2R cells among the groups of normal individuals, azathioprine-prednisolone treated, and CsA-prednisolone-treated recipients, using FITC-labelled monoclonal anti-IL-2R antibody (anti-α chain): 40.3±10.1% and 62-8±11.1% of normal PBMC (n=18), 37.0±493% and 61.7±5.8% of PRMC from azathioprine-prednisolone-treated recipients (n = 20), and 37.7±9.6% and 60.7+12.7% of PBMC from CsA prednisolone-treated recipients (n=20) expressed II.-2R after 24 h and 48 h of phytohaemagglutinin stimulation, respectively. However, in a study of Northern blotting using cDNA For IL-2R (anti-α chain specific), both the 3500 and 1400 bp families of IL-2R mRNA were remarkably decreased in PBMC from CsA-prednisolone-treated recipients compared with azathioprine-prednisolone-treated recipients and normal individuals. These studies demonstrated that CsA could inhibit IL-2R gene expression at the level of mRNA at physiological concentration. [ABSTRACT FROM AUTHOR]

Dopamine-β-hydroxylase (DBH) immunohistochemistry was used to demonstrate the noradrenergic fibers and terminals in the anterior column of the rat lumbosacral spinal segments. PAP-positive varicose fibers were widely distributed in the gray matter with preferential accumulation in the nuclear regions containing motoneurons involved in the contraction of perineal striated muscles. Unmyelinated DBH fibers were composed of nodular enlargements (varicosities, 0.4-3.0 μm in diameter) and very fine, short intervals (intervaricose segments, 0.1-0.2 μm in diameter and 1.0-4.0 μm in length). DBH-positive dense products were electron microscopically often confined within small granular particles and less frequently within large granules. Additionally, in order to characterize the innervation pattern of noradrenergic fibers on dendritic bundles organized in the motoneuronal pools innervating the pelvic small muscles, semi-quantitative analysis was done in the area of the dorsolateral nucleus endowed with especially well-developed dendritic bundles. DBH terminals contacting with unreactive dendrites were more common (67.9%) than those with neuronal somata (15.1%), and the remainder (17%) had no contacts with surrounding neuronal elements. Furthermore, specialized synaptic formations were observed in only 20.1% of these nodules. The results suggest that bulbospinal descending noradrenergic neuron systems influence the functioning of pelvic muscles principally via the neuronal contacts with dendritic bundles in the spinal cord. [ABSTRACT FROM AUTHOR]

The plaque-forming antibody response of C57BL/6 mice to rabbit gamma globulin (RGG) decreases as a function of age. RGG in tolerogenic form induces tolerance of young mice but sensitizes older animals. If antigen is administered together with lipopolysaccharide, the age-dependent decline in immune responsiveness is not observed, nor are older animals sensitized by tolerogen. The age-dependent decline in immune responsiveness is due to a loss of T helper capacity; sensitization by tolerogen is attributable to a subpopulation of B cells which becomes sensitized by the tolerogen. Older animals, treated with tolerogen, show a degree of central tolerance of T cells and a relatively slight, age-dependent diminution in colchicine- or cyclophosphamide-sensitive precursors of suppressor cells. [ABSTRACT FROM AUTHOR]

This study reports the establishment of cloned hybridomas between mouse myeloma cells (P3-X63-Ag8, 6·5·3) and spleen cells from BALB/c mice immunized with lung homogenates of nude mice (BALB/c nu/nu) heavily infected with Pneumocystis carinii. A hybridoma subclone, designated 1E12-8, produced antibodies of an IgG subclass. Using indirect immunofluorescent antibody techniques, the monoclonal antibody was found to be directed toward the pellicle antigen of air-dried P. carinii both in trophozoite and cyst forms, and to recognize the P. carinii antigen not only from nude mice but also from rats. The antibody did not cross-react with other components of the infected host lung tissue and showed little cross-reactivity with fungi examined. The monoclonal antibody should be useful in the isolation and identification of corresponding antigenic substances of P. carinii and may provide a useful tool in epidemiology, taxonomy, and diagnosis of this organism. [ABSTRACT FROM AUTHOR]

Neomycin/bovine serum albumin/gold was used as a probe to detect the binding sites of aminoglycosides on the thin sections of the cochlea embedded in Spurr. The binding sites were mainly located on the stereocilia, the cuticular plate of hair cells, the head plates of Deiters' cells, fibrous structures in pillar cells, in the spiral limbus and tectorial membrane and basilar membrane, plasma membranes, mitochondria and the chromatin of various kinds of cells. Triphosphoinositide, acidic glycosaminoglycans, and RNA were considered to be responsible for the binding activity. [ABSTRACT FROM AUTHOR]

This study was aimed at finding microorganisms capable of biodegrading dioxins efficiently to develop a biotechnological , treatment for decomposition of dioxins. Dibenzofuran (DBF) was used as a test substance to cultivate and to screen microbes active in degrading dioxins.Two microbial species (Pseudomonas aeruginosa and Xanthomonas maltaphilia) which could degrade DBF were isolated from the sludge of a Kraft pulp mill wastewater treatment plant. The optimal conditions for biodegrading DBF were 30 and pH 7. Ps. aeruginosa, which had a high growth rate with DBF as carbon source showed high growth rates in the presence of such dioxins as dibenzo-p-dioxin, medium growth with I-chlorodibenzo-p-dioxin, 2chlorodibenzo-p-dioxin and 2,8-dichlorodibenzofuran, low growth with 2,6dichlorodibenzo-p-dioxin and 1,2,3,4tetrachlorodibenzo-p-dioxin and no growth with octachlorodibenzofuran. These results suggested that tile growth rate of Ps. aeruginosa using dioxins as carbon source decreased with the increase in the degree of chlorine substitution. Activity of Ps. aeruginosa biodegrading dioxins was high for DBF, dibenzo-p-dioxin and I-chlorodibenzo-p-dioxin and lowfor 2,8dichlorodibenzofuran, 3,6-dichlorodibenzofuran, 2-chlorodibenzo-p-dioxin and 2,6-dichlorodibenzo-p-dioxin. These results suggestedthat there is a correlation between growth and the ability to biodegrade dioxins. On the other hand, the efficiency in the biodegradationof 1,2,3,4-tetrachlorodibenzo-p-dioxin was comparatively high although the growth rate on this dioxin was low. Hydroxydibenzofuran, 2-hydroxy-3-allyl-benzofuran and 2-carboxyvinyloxy phenyl acetic acid wereidentified by gas chromatograph-mass spectrometry (GC/MS) as products of DBF biodegradation by Ps. aeruginosa, suggesting a possible biodegradation pathway for dioxins. [ABSTRACT FROM AUTHOR]

A simple, low-flow rate cascade impactor operated by a battery-driven minipump was developed to collect fine airborne particulates in various environmental situations. Its performance in collecting size-fractionated particulate matter was demonstrated to be satisfactory by comparing it with a conventional TEOM particulate monitor. The samplerwas used to survey size distributions of indoor and outdoor airborneparticulates in 20 homes in several Japanese cities, 10 nonsmoking and 10 in which there was at least 1 smoker. The arithmetic mean concentrations and concentration ranges of particulate matter of less than2.5 Mum aerodynamic diameter (PM2.5) outdoors, in living rooms, kitchens and bedrooms were of similar magnitude. The minimum PM2.5/PM10 ratio was higher in bedrooms than outdoors or in other rooms, indicating that the coarse particles precipitated possibly as a result of lower turbulence due to a shorter period of occupancy and lower activity during it. The correlations betweenPM10 and PM2.5 concentrations, both indoors and outdoors, were significant. The correlations between total suspended particulates and PM10 levels were also significant. Overall no significant correlations were found between total suspended particulates,PM10 and PM2.5 concentrations outdoors and those in living rooms or bedrooms. This supports the fact that there were indoor particulate sources including tobacco smoke. [ABSTRACT FROM AUTHOR]

A survey of indoor and outdoor pollution by 10 volatile organohalogen compounds (VOHCs) was performed in Katsushika Ward, Tokyo, Japan. Thirteen houses in February and 30 houses in July were sampled. Four consecutive 24-hour samples were collected by passive sampling from living room, kitchen, bedroom, bathroom and outdoors in February and July 1995. Indoor concentrations of carbon tetrachloride and trichloroethylene were at nearly the same as outdoor concentrations; therefore,it was concluded that indoor pollution by these compounds was primarily due to penetration of outdoor pollutants. Indoor concentrations of some VOHCs were considerably higher than outdoor concentrations andthey varied widely between households. The list included: p-dichlorobenzene, tetrachloroethylene and trihalomethanes, for which emission sources were insect repellents, dry-cleaned clothes, and tap water, showers and bathtub water, respectively. Indoor concentrations of these compounds were higher in reinforced concrete houses than in wooden houses or wooden houses with mortar walls. This suggests that airtightness of the rooms is responsible for high indoor VOHC concentrations. [ABSTRACT FROM AUTHOR]