Contamination levels of PCDDs, PCDFs and Co-PCBs in commercial baby foods in Japan

To examine dioxin contamination in commercial baby foods in Japan, congener analyses of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) were performed on 102 varieties of baby foods obtained from supermarkets in 2001-2002. The toxic equivalent quantity (TEQ) levels for dioxins in samples ranged from < 0.001 to 0.135 pg-TEQ/g wet weight when undetected or trace levels of congeners were taken as zero. Among 102 samples tested, 26 samples exceeded 0.010 pg-TEQ/g. The highest TEQ value was for "sardine, vegetables" (0.135 pg-TEQ/g), followed by "Japanese radish (daikon), sardine" (0.080 pg-TEQ/g). Thus, dioxins were detected at low levels in baby foods containing animal products such as fishes and/or dairy products.     

Determination of acrylamide in processed foods by LC/MS using column switching

An LC/MS method was developed for the determination of acrylamide (AA) in processed or cooked foods. AA was extracted with a mixture of water and acetone from homogenized food samples after the addition of 13C-labeled acrylamide (AA-1-(13)C) as an internal standard. The extract was concentrated, washed with dichloromethane for defatting, and cleaned up on Bond Elut C18, PSA and ACCUCAT cartridge-columns, and then AA was determined by LC/MS in the selected ion recording (SIR) mode. For the LC/MS analysis, four LC columns were connected in-line and the flow of the mobile phase was switched according to a time-program. Monitoring ions for AA were m/z 72 and 55, and those for AA-1-(13)C were m/z 73 and 56. AA and AA-1-(13)C were determined without interference from the matrices in all samples. The recoveries of AA from potato chips, corn snack, pretzel and roasted tea spiked at the level of 500 ng/g of AA were 99.5-101.0% with standard deviations (SD) in the range from 0.3 to 1.6%. The limits of detection and quantification of the developed method were 9 and 30 ng/g for AA in samples, respectively. The method was applied to the analysis of AA in various processed or cooked food samples purchased from retail markets. High levels of AA were found in potato chips and French-fried potato (467-3,544 ng/g). Fried and sugar-coated dough cakes (karinto) contained 374 and 1,895 ng/g. Corn snacks contained 117-535 ng/g of AA. Roasted foods (such as roasted sesame seed, roasted barley (mugi-cha), roasted tea (hoji-cha), coffee beans and curry powder) contained 116-567 ng/g of AA. Foods made from fish, egg and meat contained lower levels of AA than the plant-based foods. Foods containing much water showed a tendency to have low levels of AA compared with dry foods. The proposed method was applicable to the analysis of AA in variety of processed foods.     

Fas-independent and nonapoptotic cytotoxicity mediated by a human CD4(+) T-cell clone directed against an acute myelogenous leukemia-associated DEK-CAN fusion peptide

The mechanism underlying the cytotoxicity mediated by a human CD4(+) cytotoxic T-lymphocyte (CTL) clone directed against a peptide derived from the acute myelogenous leukemia-associated fusion protein, DEK-CAN, was investigated. A DEK-CAN fusion peptide-specific CD4(+) Th0 CTL clone, designated HO-1, was established from the peripheral blood lymphocytes of a healthy individual. HO-1 exerted direct but not "innocent bystander" cytotoxicity within 2 hours. The cytotoxicity mediated by HO-1 was completely Ca2+-dependent. Because HO-1 lysed peptide-loaded Fas-deficient target cells derived from a patient with a homozygous Fas gene mutation, its cytotoxicity appeared to be mediated by a Fas-independent pathway. In addition, its cytotoxicity was only partially inhibited by treatment with concanamycin A and strontium ions, which are inhibitors of the perforin-based cytotoxic pathway. Although membrane-bound type of tumor necrosis factor-alpha (TNF-alpha) was expressed on HO-1, an anti-TNF-alpha antibody had no effect on HO-1-mediated cytotoxicity. HO-1 expressed mRNA for apoptosis-inducing mediators, including perforin, granzyme B, Fas ligand, TNF-alpha, and lymphotoxin; however, no DNA fragmentation was detected in target cells incubated with HO-1 by 5-[125I]Iodo-2'-deoxyuridine release assay and agarose gel electrophoresis of DNA. Although it has been suggested that the Fas/Fas ligand system is the main pathway by which CD4(+) CTL-mediated cytotoxicity is exerted in murine systems, HO-1 produced peptide-specific and HLA-restricted cytotoxicity via a Fas-independent and nonapoptotic pathway. The present study thus describes a novel mechanism of cytotoxicity mediated by CD4(+) CTL.     

Massive ascites as an initial sign, plasmacytoma of the cervical supine, and hyperammonemic consciousness disturbance in a patient with biclonal type multiple myeloma

Etomidate-induced suppression of cortisol biosynthesis is a result of a blockade of 11-beta-hydroxylation in the adrenal gland, mediated by the imidazol radical of etomidate. Since the generation of steroids requires reductive and energy rich equivalents, the present study examined whether supplementation with ascorbic acid or xylitol, a major source of NADPH, could attenuate adrenal suppression by etomidate in human subjects by promoting the turnover rate of 11-beta-hydroxylase. During continuous etomidate/alfentanil anaesthesia for pelviscopic surgery 30 female patients received either Ringer's lactate, xylitol (0.25 g kg-1 h-1) or ascorbic acid (0.5 g h-1) intravenously (i.v.). The plasma concentrations of cortisol, aldosterone and dehydroepiandrosterone (DHEA) were recorded for 5 h after end of surgery and a stimulation with synthetic ACTH was performed. The results showed no evidence of a clinically relevant attenuating effect of ascorbic acid or xylitol on etomidate-induced adrenocortical suppression. However, the observed suppression of cortisol levels was not enough to allow an attenuating affect to be measured.     

Modification of cleanup methods for dioxin analysis in green leafy vegetables and comparison of packing methods for a multi-layer silica gel column

To determine polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) in green leafy vegetables, the cleanup method was modified, and packing methods for a multi-layer silica gel column were compared in food samples. First, the additional cleanup was examined for a mono-ortho PCBs fraction obtained by alumina column chromatography from spinach extract. Small solids such as rough crystals that remained after concentration of the mono-ortho PCBs fraction were identified as long-chain hydrocarbons from leaf epicuticular wax by GC/MS. Cleanup using an activated carbon silica gel column with n-hexane as the washing solvent was effective. Next, multi-layer silica gel columns packed by wet packing and dry packing were compared using komatsuna, salmon and butter as samples. The columns prepared by both methods gave similar values at each isomeric concentration level and showed similar efficiency with favorable recoveries.     

Analysis of protein adsorption and binding at biosensor polymer interfaces using X-ray photon spectroscopy and scanning electrochemical microscopy

We describe a method, based on X-ray photoelectron spectroscopy (XPS) measurements, to assess the extent of protein adsorption or binding on a variety of different muTAS and biosensor interfaces. Underpinning this method is the labeling of protein molecules with either iodine- or bromine-containing motifs by using protocols previously developed for radiotracer studies. Using this method, we have examined the adsorption and binding properties of a variety of modified electrodeposited polymer interfaces as well as other materials used in muTAS device fabrication. Using polymer interfaces modified with poly(propylene glycol) (PPG) chains, our results indicate that a chain of at least approximately 30 monomer units is required to inhibit nonspecific adsorption from concentrated protein solutions. The XPS methodology was also used to probe specific binding of avidins and enzyme conjugates thereof to biotinylated and mixed biotin/PPG-modified polymer interfaces. In one example, using competitive binding, it was established that the mode of binding of a peroxidase-streptavidin conjugate to a biotinylated modified polymer interface was primarily via the streptavidin moiety (as opposed to nonspecific binding via the enzyme conjugate). XPS evaluation of nonspecific and specific peroxidase-streptavidin immobilization on various functionalized polymers has guided the design and fabrication of functionalized interdigitated electrodes in a biosensing muTAS device. Subsequent characterization of this device using scanning electrochemical microscopy (SECM) corroborated the adsorption and binding previously inferred from XPS measurements on macroscale electrodes.     

Selection of manipulator system for multiple-goal task by evaluating task completion time and cost with computational time constraints

The focus of this study is on the problem of manipulator system selection for a multiple-goal task by evaluating task completion time and cost with computational time constraints. An approach integrating system selection, structural configuration design, layout design, motion planning, and relative cost calculation is proposed to solve this problem within a reasonable computational time. In the proposed approach, multiple-objective particle swarm optimization (MOPSO) is utilized to search for the appropriate manipulator system with appropriate structural configuration from a set of candidate systems. Particle swarm optimization (PSO) and the nearest neighborhood algorithm are employed in layout design and motion planning due to their high convergence speed. Three methods involving a random search algorithm are compared to the proposed approach through a simulation. The simulation is done with a set of tasks and the result shows the effectiveness of the proposed approach.     

TiO2 thin films using organic liquid materials prepared by Hot-Wire CVD method

TiO₂ thin films prepared by Hot-Wire CVD method have been studied as a protecting material of transparent conducting oxide (TCO) against atomic hydrogen exposures for the fabrications of Si thin film solar cells. It was found that electrical conductivity of the films at room temperature reached a value of 0.4 S/cm. This value is 2-3 orders of magnitude higher than that of TiO₂ films prepared by RF magnetron sputtering and electron-beam evaporation methods in our previous works. The conductivity improvement seems to be partly due to the enlargement of TiO₂ crystallites.     

Estimation of concentrations of antifungal agents allowed as food additives in foods and their daily intake based on official inspection results in Japan in fiscal year 1998

The mean concentrations and daily intake of four antifungal agents were estimated based on the results of an analysis of 7,005 samples of food obtained in official inspections by Japanese local governments in fiscal year 1998. The mean concentration of diphenyl was 0.0004% of the allowable limit, and those of imazalil, o-phenylphenol, and thiabendazole were 14.0%, 3.5%, and 5.7%, respectively. The daily intakes of these antifungal agents per person, estimated from their concentrations and the daily consumption of the foods, were 0.000326, 1.89, 11.5, and 23.3 micrograms, respectively, and assuming a body weight of 50 kg, the amounts of these antifungal agents consumed were 0.000013%, 0.15%, 0.12%, and 0.47% of the acceptable daily intake, respectively. These values are similar to the values obtained on the basis of the results of the official inspection in fiscal years 1994 and 1996, except that the amount of diphenyl is much lower (1/100).