Development of a processing factor prediction model for pesticides in processed tomato foods using elastic net regularization

A novel regularized elastic net regression model was developed to predict processing factor (PF) for pesticide residues, which represents a change in the residue levels during food processing. The PF values for tomato juice, wet pomace and dry pomace in the evaluations and reports published by the Joint FAO/WHO Meeting on Pesticide Residues significantly correlated with the physicochemical properties of pesticides, and subsequently the correlation was observed in the present tomato processing study. The elastic net regression model predicted the PF values using the physicochemical properties as predictor variables for both training and test data within a 2-fold range for 80-100% of the pesticides tested in the tomato processing study while overcoming multicollinearity. These results suggest that the PF values are predictable at a certain degree of accuracy from the unique sets of physicochemical properties of pesticides using the developed model based on a processing study with representative pesticides.

Polychlorinated Biphenyl Concentrations and Estimated Intakes in Fish Oil Supplements on the Japanese Market

Polychlorinated biphenyls (PCBs) are synthetic organic contaminants that are widespread in the environment. There are 209 PCB congeners. Fish oil produced from marine fish is widely used as a health supplement. PCB contamination of fish oil is of concern. We determined the concentrations of all 209 PCB congeners in commercially available fish oil supplements from Japan and estimated PCB intakes for humans consuming the supplements. We determined the concentrations of non-dioxin-like PCBs separately. The total PCB concentrations in 37 fish oil supplements purchased in Japan were 0.024-19 ng/g whole weight, and the non-dioxin-like PCB concentration range was also 0.024-19 ng/g whole weight. The total PCB intakes calculated for a 50 kg human consuming the supplements were 0.039-51 ng/day (0.00078-1.0 ng/(kg body weight per day)) and the non-dioxin-like PCB intake range was also 0.039-51 ng/day (0.00078-1.0 ng/(kg body weight per day)). The total PCB intakes were much lower than the tolerable daily intake of 20 ng/(kg body weight per day) recommended by the WHO. The results indicated that PCBs in the fish oil supplements pose acceptable risks to humans consuming the fish oil supplements daily.

[Analytical Method for Melengestrol Acetate in Livestock Products Using LC-MS/MS]

The present study verified that it is possible to analyze melengesterol acetate using the existing multi-residue method. Melengestrol acetate was extracted from livestock products using acidic acetonitrile acidified with acetic acid in the presence of n-hexane and anhydrous sodium sulfate. The crude extracts were cleaned up using an octadecylsilanized silica gel cartridge column. Separation by HPLC was performed using an octadecylsilanized silica gel column with linear gradient elution of 0.1 vol% formic acid and acetonitrile containing 0.1 vol% formic acid. For the determination of the analyte, tandem mass spectrometry with positive ion electrospray ionization was used. In recovery tests using four livestock products fortified with maximum residue limits levels of melengestrol acetate (0.001-0.02 mg/kg), the truenesses ranged from 82% to 100%, and the repeatabilities for the entire procedure ranged from 0.5 RSD% to 5.6 RSD%. In recovery tests using 11 livestock products fortified with 0.0005 mg/kg of melengestrol acetate, the truenesses ranged from 88% to 99%, and the repeatabilities ranged from 1.3 RSD% to 5.4 RSD%. The limit of quantification for melengestrol acetate in livestock products was 0.0005 mg/kg.

Measuring linguistics of the wokototen chart made inductively by deciphering kunten materials

In this paper, we focus on wokototen markings, which are a system of kunten annotations used to facilitate the reading of classical Chinese documents by Japanese readers. Using digitized data, we performed basic measurements of wokototen by using a chart that summarizes the wokototen markings of actual kunten materials described by Hiroshi Tsukishima, and we quantitatively clarified their characteristics. Kunten materials are classical Chinese books with annotations, called kunten, on the Chinese text. The wokototen is a type of kunten. In ancient East Asian countries, kunten systems were developed as a way of directly annotating Chinese documents so that they could be read and understood by non-native readers. For this reason, kunten materials and kunten are treated as historical sources for linguistic and historical research. The shape and position of a wokototen marking determines what kind of reading it indicates. The results of our basic survey quantitatively show that almost all the wokototen charts in actual kunten materials contain particles represented by "te", "ni", and "wo", the most common shapes of wokototen are dots and shapes that can be written with a single stroke, such as ｜, ─, and ＼, and that the most common places to find these markings are to the right of characters in the horizontal direction and below characters in the vertical direction.

[Estimation of the Distribution of Dietary Exposure to Lead Using Two-Dimensional Monte Carlo Simulation: An Attempt to Apply to Total Diet Samples]

The average dietary exposure to lead (Pb) in male and female Japanese individuals >1 year of age was estimated using 280 total diet samples representing 14 food groups from 10 areas over a two-year period. A probabilistic exposure estimation was performed using a two-dimensional Monte Carlo simulation (2D-MCS) with a Bayesian estimation that consided the uncertainty of the estimation process. The Bayesian estimation was performed using the likelihood function with cumulative distribution function between the lower and upper boundary values for no-detected values. The median dietary exposure to Pb was estimated as 5.82 μg/person/day. The 90% interval was 2.51-16.9 μg/person/day. Comparison with previously reported Pb exposure values indicates that the estimation of Pb exposure distribution using total diet samples is reasonable. The contribution to Pb exposure was highest in the order of food group 8 (light-colored vegetables, mushrooms, and seaweeds: 20.0±16.1%)>food group 1 (rice and rice products: 12.3±19.0%)>food group 10 (fish and shellfish: 10.5±13.9%). Owing to the high uncertainties of contribution ratios, it was not possible to identify dominant food groups contributing to Pb exposure. However, it was evident that the uncertainty of the estimation of Pb exposure was influenced by the uncertainty of Pb concentration than the uncertainty of food consumption rate. In particular, the effect of uncertainty from the Pb concentration of the food group 1 was 68.2%. When the margin of exposures were calculated, the estimated probabilities that a value would be <1 were 14.5% for developmental neurotoxicity to children (1-6 years old), 0.13% for blood pressure and 0.93% for kidney disease in Japanese individuals ≥1 year of age. The findings suggest that the health risk due to dietary Pb exposure is small but not negligible.

[An LC-MS/MS Analytical Method for Moenomycin A in Livestock Products]

A simple and sensitive method for the determination of moenomycin A residues in livestock products using LC-MS/MS was developed. Moenomycin A, a residual definition of flavophospholipol, was extracted from samples with a mixture of ammonium hydroxide and methanol (1 : 9, v/v) preheated at 50℃. The crude extracted solutions were evaporated and purified by liquid-liquid partitioning between a mixture of ammonium hydroxide, methanol and water (1 : 60 : 40, v/v/v) and ethyl acetate. The alkaline layer was taken, and cleaned up using a strong anion exchange (InertSep SAX) solid phase extraction cartridge. The LC separation was performed on an Inertsil C8 column with liner gradient elution using 0.3 vol% formic acid and acetonitrile containing 0.3 vol% formic acid. Moenomycin A was detected using tandem mass spectrometry with negative ion electrospray ionization. Recovery tests were conducted using three porcine samples (muscle, fat and liver) and chicken eggs. Samples were spiked with moenomycin A at 0.01 mg/kg and at the Japanese Maximum Residue Limits (MRLs) established for each sample. The trueness ranged from 79 to 93% and precision ranged from 0.5 to 2.8%. The limit of quantification (S/N≥10) of the developed method is 0.01 mg/kg. The developed method would thus be very useful for regulatory monitoring of flavophospholipol in livestock products.

[Method Improvement for Quantitative Analysis of Chlorophyll Degradation Compounds, Including Pheophorbide, in Chlorella Products]

An official analytical method for chlorophyll degradation compounds, including pheophorbide, in chlorella products, is described in notification Kanshoku No. 99 (May 8, 1981). However, this method has several operational issues, such as the formation of emulsion during liquid-liquid partitioning. Additionally, impurities present in the reagents (sodium sulfate decahydrate or anhydrous sodium sulfate) used to prepare saturated sodium sulfate solution can degrade pheophorbide and other related compounds, resulting in a significant decrease in analytical values. In this study, we thoroughly examined each step of the official method to enhance the operability and develop an alternative method that eliminates the need for saturated sodium sulfate solution. The developed method was evaluated for pheophorbide a and pyropheophorbide a at 100 mg%. Satisfactory analytical performance was achieved with trueness of 100% for pheophorbide a and 90% for pyropheophorbide a, and relative standard deviations of intra- and inter-day precision below 5% for both compounds. The proposed method is considered suitable for regulatory analysis of chlorophyll degradation compounds and would be useful for quality control of chlorella products.

Determination of Cyanide and Cyanoglycosides in Sweetened Bean Paste by HPLC with Fluorescence Detection

It is necessary to evaluate the efficiency of reduction for cyanide and cyanoglycosides during the manufacturing process from raw material beans to sweetened bean paste in a food hygiene control system from the viewpoint of food safety. Analytical methods for cyanide and cyanoglycoside determination in sweetened bean paste by HPLC with fluorescence detection were developed. In analysis of collection time of free cyanide in the free cyanide assay, the recovery was improved by extending the collection time, the recovery rate was >80% by 2 h. The accuracy, repeatability and intra-laboratory precision of the free cyanide assay were 82.3, 2.0, and 2.4%, respectively. The method for cyanoglycoside analysis was evaluated by 5 repeated spiked recovery experiments at a concentration of 10 ppm. The accuracy, repeatability and intra-laboratory precision of the cyanoglycoside method were 82.2, 1.9, and 3.4%, respectively. These analytical methods will enable the analysis of cyanide and cyanoglycosides in sweetened bean paste without using steam distillation method in the pretreatment.

[Development of Analytical Method and Surveillance ofGibberellic Acid in Banana, Cherry, and Kiwi Fruit]

Gibberellic acid (GA3) is commonly used as a plant growth regulator in many food crops owing to its essential signaling functions during plant growth and development. In Japan, a threshold for administrative action for GA3 content of 0.3 mg/kg applies in produce in which maximum residue limits have not been established. Although the threshold is based on previous studies, the GA3 concentrations in individual foods are still unknown. Thus, we surveyed the concentrations of GA3 in banana, cherry, and kiwi fruit on the Japanese market. We developed and validated a method for the analysis of GA3 using solid-phase extraction and LC-MS/MS in accordance with accepted criteria of trueness, repeatability, and selectivity. The limits of detection and of quantification were determined as 0.005 and 0.05 mg/kg, respectively, in all fruits. Concentrations of GA3 did not exceed 0.3 mg/kg regardless of ripeness, suggesting the reasonability of the current regulation of GA3 in banana, cherry, and kiwi fruit. These findings can support prompt administrative action on these fruits, contributing to the regulation of GA3 in Japan.

Estimation of dietary intake of 90Sr in Japan after the Fukushima Daiichi Nuclear Power Plant accident: market basket study, 2013-2018

Radionuclide contamination in foods has been a public concern in Japan after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. To estimate time and regional trends of daily intake and annual committed effective dose of strontium-90 (⁹⁰Sr) after the accident, we analysed Market basket samples using a low background 2π gas-flow counter. Samples were collected from six regions, once a year from 2013 to 2018. There appeared to be little variation in estimated daily intake and annual committed effective dose of ⁹⁰Sr across the time periods and regions. The estimated maximum annual committed effective dose of ⁹⁰Sr was 0.00076 mSv/year, a value sufficiently lower than the intervention exemption level, 1 mSv/year, in foods in Japan. There was no noticeable difference between the range of estimated daily intake of ⁹⁰Sr in this study compared with daily intake measured before the FDNPP accident. These results suggested that no obvious increase in dietary intake of ⁹⁰Sr was observed after the FDNPP accident, and that the effects on commercial foods from ⁹⁰Sr due to the FDNPP accident were negligible.

Comprehensive analysis of a decade of cumulative radiocesium testing data for foodstuffs throughout Japan after the 2011 Fukushima Daiichi Nuclear Power Plant accident

The unexpected accident at the Fukushima Daiichi Nuclear Power Station in Japan, which occurred on March 11th, 2011, after the Great East Japan Earthquake and tsunami struck the north-eastern coast of Japan, released radionuclides into the environment. Today, because of the amounts of radionuclides released and their relatively long half-life, the levels of radiocesium contaminating foodstuffs remain a significant food safety concern. Foodstuffs in Japan have been sampled and monitored for ^134,137Cs since the accident. More than 2.5 million samples of foodstuffs have been examined with the results reported monthly during each Japanese fiscal year (FY, from April 1^st to March 31^st) from 2012 to 2021. A total of 5,695 samples of foodstuffs within the “general foodstuffs” category collected during this whole period and 13 foodstuffs within the “drinking water including soft drinks containing tea as a raw material” category sampled in FY 2012 were found to exceed the Japanese maximum permitted level (JML) set at 100 and 10 Bq/kg, respectively. No samples from the “milk and infant foodstuffs” category exceeded the JML (50 Bq/kg). The annual proportions of foodstuffs exceeding the JML in the “general foodstuffs” category varied between 0.37% and 2.57%, and were highest in FY 2012. The ^134,137Cs concentration for more than 99% of the foodstuffs monitored and reported has been low and not exceeding the JML in recent years, except for those foodstuffs that are difficult to cultivate, feed or manage, such as wild mushrooms, plants, animals and fish. The monitoring data for foodstuffs show the current status of food safety risks from ^134,137Cs contamination, particularly for cultured and aquaculture foodstuffs on the market in Japan.

Chemical identification of an active component and putative neural mechanism for repellent effect of a native ant’s odor on invasive species

The invasive Argentine ants (Linepithema humile) and the red imported fire ants (Solenopsis invicta) constitute a worldwide threat, causing severe disruption to ecological systems and harming human welfare. In view of the limited success of current pest control measures, we propose here to employ repellents as means to mitigate the effect of these species. We demonstrate that cuticular hydrocarbons (CHCs) used as nestmate-recognition pheromone in the Japanese carpenter ant (Camponotus japonicus), and particularly its (Z)-9-tricosene component, induced vigorous olfactory response and intense aversion in these invasive species. (Z)-9-Tricosene, when given to their antennae, caused indiscriminate glomerular activation of antennal lobe (AL) regions, creating neural disarray and leading to aversive behavior. Considering the putative massive central neural effect, we suggest that the appropriate use of certain CHCs of native ants can facilitate aversive withdrawal of invasive ants.

Reaction Mechanism and Selectivity Control of Si Compound ALE Based on Plasma Modification and F-Radical Exposure

In this work, atomic layer etching (ALE) of Si compounds using H₂ or N₂ plasma modification followed by fluorine radical exposure is discussed. It is shown that the H₂ plasma modification process promotes the selective etching of SiN, SiC, and SiCO versus SiO₂. The N₂ plasma modification, on the other hand, enables the selective etching of SiC and SiCO versus SiN and SiO₂. The origin of the etching selectivity between different Si compounds is investigated using a combination of in situ SE and FTIR supported by several ex situ analysis techniques. It is shown that the formation of a hydrogen-rich layer after plasma modification is essential to enable the ALE process. The hydrogen-rich layer can be formed due to ion and radicals of the modification plasma (H₂ plasma modification) or be a result of the reconfiguration of hydrogen that is already present in the film (N₂ plasma modification). The obtained insights are expected to further enhance the etching selectivity of Si compound ALE processes. Furthermore, it is anticipated that the process can be extended to many other compound materials such as Ti and Hf, as well as enable selective etching between their oxides, carbides, and nitrides.

Simple and rapid determination of biogenic amines in fish and fish products by liquid chromatography-tandem mass spectrometry using 2,4,6-triethyl-3,5-dimethyl pyrylium trifluoromethanesulfonate as a derivatization reagent

A simple and rapid analytical method was developed for determination of four biogenic amines [histamine (Him), cadaverine (Cad), tyramine (Tym), 2-phenylethylamine (Pea)] in fish and fish products. This method uses a new derivatization reagent, 2,4,6-triethyl-3,5-dimethyl pyrylium trifluoromethanesulfonate (Py-Tag). The four biogenic amines in the samples were extracted with trichloroacetic acid. The diluted extract was derivatized with Py-Tag (15 min at 50°C) and then subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS). The limits of quantification for the method were 2 mg/kg for Him, Tym, and Pea and 10 mg/kg for Cad. The matrix effects derived from the tested fish and fish products were negligible in the LC-MS/MS analysis. The impact of the sample matrices on the Py-Tag derivatization was also negligible. The trueness and repeatability of the method were assessed by performing replicate analyses (n = 5) of five samples of fish and fish products, each spiked with the four biogenic amines at three different concentration levels. Analysis of the samples found 87%-104% of the spiked concentrations and the relative standard deviations were <6.1%. A reference sample and quality control canned fish samples were analyzed by the method, and the concentrations of the Him were within acceptable limits. The developed method was successfully used to determine concentrations of the four biogenic amines in 48 fish and fish products on the Japanese market. The developed method does not require cleanup using a solid-phase extraction column or similar, and the derivatization reaction time was only 15 min. The results suggested that the present method is reliable and suitable for rapid analysis of the four biogenic amines in fish and fish products.

Monitoring Analysis of Perfluoroalkyl Substances and F-53B in Bottled Water, Tea and Juice Samples by LC-MS/MS

Monitoring analysis of 14 per- and polyfluoroalkyl substances (PFAS), 9-chlorohexadecafluoro-3-oxanonane-1-sulfonate (F-53B) and dodecafluoro-3H-4,8-dioxanonanoate (ADONA) in bottled drinking water, tea and juice samples was performed using LC coupled with tandem mass spectrometry (LC-MS/MS) and solid-phase extraction (SPE). In the electrospray negative ion mode, the limit of detection and limit of quantification (LOQ) values were 0.1 to 0.8 ng/mL and 0.2 to 1.6 ng/mL, respectively. The calibration curves were linear from LOQ to 50 ng/mL (r² > 0.999). The SPE procedure (Presep PFC-II) was utilized for sample preparation and recovery rates for three standards (35, 70 and 140 ng/L) were 80.4-118.8% with relative standard deviation (RSD) ≤ 0.6%. Using the developed method, various samples (n = 54) from Japanese markets were investigated for PFAS and F-53B contamination, and values below the LOQ were observed. It is concluded that for monitoring products in the Japanese market, our method represents a significant improvement over complex techniques for the quantification of PFAS and related compounds from various foods.

Concentrations of Polycyclic Aromatic Hydrocarbons in Smoked Foods in Japan

ABSTRACT

We evaluated the performance of a gas chromatography-tandem mass spectrometry method for quantifying 16 polycyclic aromatic hydrocarbons (PAHs), which the Scientific Committee on Food and the Joint Food and Agriculture Organization of the United Nations/World Health Organization Expert Committee on Food Additives have considered to be of concern to human health and used the method to determine the PAH concentrations in smoked foods. Eighty-seven samples of smoked fish, smoked meat, smoked eggs, dried bonito flakes, and dried bonito-related soup-stock products (disposable powder packets for infusion, instant bouillons, and liquids) were purchased in Japan to analyze their content of the 16 PAHs. Because of the low certainty of some results, the analytical values for some PAHs (e.g., benzo[c]fluorene, chrysene, and dibenzo[a,h]pyrene) are given for informational purposes only. The highest median concentrations of benzo[a]pyrene and the sum of all the 16 PAHs (29 and 760 μg/kg, respectively) were found in the disposable powder packets, followed by dried bonito flakes (24 and 512 μg/kg, respectively), and instant bouillons (11 and 227 μg/kg, respectively). These concentrations were much higher than those in the other products tested. We also investigated the percentages of the PAHs transferred from dried bonito flakes and a disposable powder packet to soup stocks commonly prepared at home. These were extremely low (<4%), even though they contained relatively high concentrations of the PAHs. Finally, the intake of benzo[a]pyrene and the sum of the intakes of four PAHs, as a marker proposed by the European Food Safety Authority, were estimated based on the data from a Japanese food consumption survey and the mean concentrations found in smoked fish and smoked fish products. These estimates suggest intakes of PAHs pose a low concern for consumer health.

HIGHLIGHTS

Enzyme Immunoassay for Direct Determination of Microcystins in Environmental Water

An enzyme-linked immunosorbent assay (ELISA) was developed for direct quantitation of microcys- tins (MCs), a group of freshwater cyanobacterial toxins. An anti-MC monoclonal antibody exhibiting broad cross-reactivity to major MC derivatives was used. The detection limit and linear range of the ELISA standard curve with microcystin-(leucine-ar-ginine) (MCLR), a variant of MCs, were 20 and 20–500 pg/mL, respectively. For analysis of MC released from cyanobacterial cells, water sample filtered through a glass fiber filter was applied directly to ELISA. For analysis of total MC (released MC plus intracellular MC), intracellular toxin was extracted by freeze-thawing twice before filtration. Mean recovery of MCLR added to tap water and toxin-free environmental water was 101%, with a coefficient of variation (CV) of 7.3% at toxin levels of 20–500 pg/mL. Mean recovery of MCLR added to toxin-free cyanobacterial extracts was 93%, with a CV of 12.5% at toxin levels of 50–500 pg/mL. At 20 pg/mL, an increasing matrix effect on assay variance was observed; therefore, both released MC and total MC were measured in the range 50–500 pg/ mL. Comparative studies with a liquid chromatographic (LC) method showed that the ELISA gives a reliable correlation with LC for analysis of MC in water extracts of natural blooms and cultured cyanobacterial cells (r = 0.98). The ELISA was applied to water samples collected from lakes and ponds in Japan. In 4 of 13 and 12 of 17 samples, 81–800 pg released MC/mL and 64–94 000 pg total MC/mL were detected, respectively. By LC separation followed by the ELISA analysis, the presence of MCLR, microcystin-arginine-arginine, and micro-cystin-tyrosine-arginine were confirmed in 4 ELISA-positive samples selected randomly. The newly developed ELISA is a reliable and powerful method for mass monitoring of MC levels in environmental water.

[Development of a Rapid Determination Method for Strontium-90 in Foods Using a Strontium Extraction Column for Use during Emergency Events]

To ensure food safety during emergency events such as nuclear disasters, we developed a practical rapid determination method for strontium-90 (Sr-90) in foods. Purification of Sr from foods was simplified using a commercial Sr-extraction column. We also reduced the waiting time to achieve radiative equilibrium between Sr-90 and Y-90. Finally, we developed a rapid determination method for Sr-90 that can be completed in about a week. Using the new method, stable Sr recoveries exceeded 85%. The trueness of the method ranged from 109 to 115% and the detection limit of Sr-90 was estimated to be 0.07 Bq/kg fresh weight according to a performance evaluation using standard materials. Sr-90 radioactivity concentrations in food samples determined by the new method were highly correlated and nearly equal to concentrations determined by the conventional method. The present study suggests that the new method offers highly sensitive and rapid detection of Sr-90 which are necessary attributes for food tests during emergency events.

Effect of Systematic Conversion to Generic Mycophenolate Mofetil (MMF) in Kidney Transplantation: A Single-Center Clinical Experience from Japan

INTRODUCTION

Recently, more and more generic drugs have been used for immunosuppressive drugs in the field of organ transplantation. Some reports have indicated that blood concentration of most generic drugs is difficult to maintain stability, and it may cause the difference in graft survival of transplanted organs between original drugs and generic drugs. In this article, we report the cases could not maintain blood concentration of generic drugs of mycophenolate mofetil (MMF).

RESULTS

In 4 cases out of 5 cases that we had to change original MMF to generic MMF, there were cases that blood concentration level was not stabilized. There were possibility that the lowered blood concentration level of MMF caused a rejection, in two cases. Mean MMF trough level was decreased from 3.6 ± 1.9 μg/mL to 0.6 ± 0.4 μg/mL. Due to the early detection, it did not become severe or failure of graft function, however, we cannot deny the possibilities that side effects were increased and rejection rose. In these cases, we discontinued to use the generic drugs thereafter due to unstable plasma concentration of MMF.

DISCUSSION

Some reports have indicated that failure to maintain plasma concentration of MMF leads to rejection. Therefore, maintenance of effective plasma concentration and prevention of rejection are essential to long-term graft survival in kidney transplant.

CONCLUSION

Generic drug formulations may exhibit differences in effects and absorption compared to the brand-name drug. If the generic drug should be used, patients should be closely monitored.

[Concentration of Radioactive Cesium in Domestic Foods Collected from the Japanese Market in Fiscal Years 2014-2016]

Between fiscal years 2014 and 2016, we surveyed the concentration of radioactive cesium in commercial foods produced in areas where there is a risk of radiation contamination due to the Fukushima Daiichi nuclear disaster. The number of samples with a concentration of radioactive cesium that exceeded the regulatory limit （100 Bq/kg for general foods） was 9 out of 1,516 （0.6％） in fiscal 2014, 12 out of 900 （1.3％） in fiscal 2015, and 10 out of 654 （1.5％） in fiscal 2016. Even though some samples were expected to be contaminated with radioactive cesium, because wild mushrooms and edible wild plants were intentionally included in this survey, the percentage of samples that exceeded the regulatory limit was only around 1％. The surveillance results confirmed that the pre-shipment food monitoring conducted by local governments was properly and efficiently performed, although continuous monitoring of the concentration of radioactive cesium in cultivated and wild mushrooms, edible wild plants, and wild animal meats is still required.

Safety of Elderly Living Kidney Donors: 2 Cases of Donors Older Than 80 Years: A Case Report

Much controversy exists over the performance of elderly living donor kidney transplantation. We report the safety of 2 cases of elderly living kidney donations in our hospital. CASE 1: An 82-year-old man was a living kidney donor for his 56-year-old son. The donor suffered from hypertension, but has successfully managed his blood pressure with only one medication. His serum creatinine was 0.7 mg/dL and inulin clearance was 122.5 mL/min, which met the usual criteria for living kidney donors. This was his son's secondary kidney transplantation, and no other donors existed. CASE 2: An 80-year-old woman was a living kidney donor for her 45-year-old son. Her serum creatinine was 0.61 mg/dL and inulin clearance was 71.7 mL/min, which met the marginal kidney donor criteria. In both cases, we determined that the donor kidney function was acceptable. Though we explained the risks of the transplantation thoroughly, the patients' strong will to offer a kidney to their family member did not change. We decided to carry out the transplantation. At the time of publication, nearly 2 years have passed since the transplantation, but both donors and recipients are doing well. In the future, it seems more likely that the number of elderly living donor kidney transplantation will rise. On one hand, there is no absolute contraindication for elderly donors, while on the other hand, the criteria for a living kidney donor must be strictly examined. Furthermore, careful observation of both donors and recipients after transplantation is required.

Dietary intake of dioxins in Japan in 2016 with time trends since 1998

Total diet samples collected from seven regions throughout Japan in 2016 were analysed for polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and dioxin-like polychlorinated biphenyls (DL-PCBs), known collectively as dioxins. This led to estimates of the latest dietary intake of these contaminants for the general Japanese population (≥1 year old). The average daily intake of dioxins for a person weighing 50 kg, calculated at non-detected congener concentrations assumed to be equal to zero, was estimated to be 0.54 pg TEQ (toxic equivalents) kg^-1 body weight (bw) day^-1. This value is well below the tolerable daily intake of 4 pg TEQ kg^-1 bw day^-1 for dioxins in Japan. The average intake was highest from fish and shellfish, followed by meat and eggs. The TEQ contribution of the fish and shellfish group to the total dietary TEQs was significant (89%). The DL-PCBs accounted for about 67% of the dioxin intake. The latest dioxin intake level was compared with previous estimates from total diet study results obtained annually since 1998 to determine the time trends in the dietary intake of dioxins in Japan. Overall, the average dioxin intake appeared to be decreasing gradually during the period of study. The previous average intakes of dioxins ranged from 0.58 to 1.9 pg TEQ kg^-1 bw day^-1. The latest average intake was the lowest since 1998 and was about one-third of the average intake in 1998. This decreasing trend in the dietary intake of dioxins was mainly influenced by the decreased dioxin intakes from two food groups, fish and shellfish, and meat and eggs.

Dioxin concentrations in dietary supplements containing animal oil on the Japanese market between 2007 and 2014

We determined the concentrations of dioxins (polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls) in 46 dietary supplement products, containing the oil of fish, marine mammals, or egg yolk, on the Japanese market between 2007 and 2014. Dioxins were detected in 43 of the 46 products tested at concentrations from 0.00015 to 67 pg TEQ/g. The highest concentration of dioxins was found in a shark liver oil product which varied insignificantly in five batches collected over a two-year period. The dioxin intakes from these five batches reached 2.3-2.8 pg TEQ/kg bw/day, or 58%-70%, respectively, of the Japanese tolerable daily intake (TDI) of 4 pg TEQ/kg bw/day. However, the dioxin intakes from most of the other products tested were less than 5% of the TDI. Although rare, supplements based on animal oils may contain relatively high concentrations of dioxins, leading to a substantial increase in dioxin intakes.

Determination of polychlorinated biphenyls in marine fish obtained from tsunami-stricken areas of Japan

We determined the polychlorinated biphenyl (PCB) congeners in 101 marine fish obtained from tsunami-stricken areas following the Great East Japan Earthquake in 2011. In particular, to determine the degree of PCB contamination in the fish, we investigated the concentration of total PCB (∑PCB) and the proportions of 209 individual PCB congeners by high-resolution gas chromatography/high-resolution mass spectrometry. The ∑PCB concentration was 1.7–33 ng/g in fat greenling (n = 29), 0.44–25 ng/g in flounder (n = 36), and 1.6–86 ng/g in mackerel (n = 36), all values being much lower than the provisional regulatory limit in Japan. In the congener analysis, tetra-, penta-, hexa-, and hepta-chlorinated PCB congeners dominated in all samples (comprising over 86% of the ∑PCB). The proportions of the chlorinated PCB congeners were similar to the contamination patterns derived from Kanechlor in the environment, implying that the marine fish were not contaminated with fresh PCBs.

Detection of Aryl Hydrocarbon Receptor Activation by Some Chemicals in Food Using a Reporter Gene Assay

The purpose of this study was to examine whether a simple bioassay used for the detection of dioxins (DXNs) could be applied to detect trace amounts of harmful DXN-like substances in food products. To identify substances with possible DXN-like activity, we assessed the ability of various compounds in the environment to bind the aryl hydrocarbon receptor (AhR) that binds specifically to DXNs. The compounds tested included 19 polycyclic aromatic hydrocarbons (PAHs), 20 PAH derivatives (nitrated, halogenated, and aminated derivatives), 23 pesticides, six amino acids, and eight amino acid metabolites. The AhR binding activities (AhR activity) of these compounds were measured using the chemical activated luciferase gene expression (CALUX) reporter gene assay system. The majority of the PAHs exhibited marked AhR activity that increased in a concentration-dependent manner. Furthermore, there was a positive link between AhR activity and the number of aromatic rings in the PAH derivatives. Conversely, there appeared to be a negative correlation between AhR activity and the number of chlorine residues present on halogenated PAH derivatives. However, there was no correlation between AhR activity and the number and position of substituents among nitrated and aminated derivatives. Among the pesticides tested, the indole-type compounds carbendazim and thiabendazole showed high levels of activity. Similarly, the indole compound tryptamine was the only amino acid metabolite to induce AhR activity. The results are useful in understanding the identification and characterization of AhR ligands in the CALUX assay.

The role of plasma chemistry on functional silicon nitride film properties deposited at low-temperature by mixing two frequency powers using PECVD

A correlation study of plasma parameters and film properties and the implication of dual frequency PECVD for industry are proposed.

[Surveillance of radioactive cesium in domestic foods on the Japanese market (Fiscal Years 2012 and 2013)]

We surveyed the concentration of radioactive cesium in foods purchased at markets in areas where possible contamination has been a concern after the Fukushima accident. In fiscal years 2012 and 2013, we surveyed 1,735 and 1,674 foods, respectively, using a NaI (Tl) scintillation spectrometer for the screening test and a γ-ray spectrometer with a germanium semiconductor detector for the final test. Only 3 and 4 samples (0.2% of our total samples) exceeded the regulatory limit (100 Bq/kg) for radioactive cesium in fiscal years 2012 and 2013, respectively. Our surveillance indicates that the pre-shipment monitoring of foods by local governments has been working effectively.

Development of Species-Specific Ah Receptor-Responsive Third Generation CALUX Cell Lines with Enhanced Responsiveness and Improved Detection Limits

The Ah receptor (AhR)-responsive CALUX (chemically activated luciferase expression) cell bioassay is commonly used for rapid screening of samples for the presence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin), dioxin-like compounds, and AhR agonists/antagonists. By increasing the number of AhR DNA recognition sites (dioxin responsive elements), we previously generated a novel third generation (G3) recombinant AhR-responsive mouse CALUX cell line (H1L7.5c3) with a significantly enhanced response to DLCs compared to existing AhR-CALUX cell bioassays. However, the elevated background luciferase activity of these cells and the absence of comparable G3 cell lines derived from other species have limited their utility for screening purposes. Here, we describe the development and characterization of species-specific G3 recombinant AhR-responsive CALUX cell lines (rat, human, and guinea pig) that exhibit significantly improved limit of detection and dramatically increased TCDD induction response. The low background luciferase activity, low minimal detection limit (0.1 pM TCDD) and enhanced induction response of the rat G3 cell line (H4L7.5c2) over the H1L7.5c3 mouse G3 cells, identifies them as a more optimal cell line for screening purposes. The utility of the new G3 CALUX cell lines were demonstrated by screening sediment extracts and a small chemical compound library for the presence of AhR agonists. The improved limit of detection and increased response of these new G3 CALUX cell lines will facilitate species-specific analysis of DLCs and AhR agonists in samples with low levels of contamination and/or in small sample volumes.

[Estimation of dietary intake of radioactive materials by total diet methods]

Radioactive contamination in foods is a matter of great concern after the Tokyo Electric Power Company's Fukushima Daiichi nuclear power plant disaster caused by the Great East Japan Earthquake. In order to estimate human intake and annual committed effective dose of radioactive materials, market basket and duplicate diet samples from various areas in Japan were analyzed for cesium-134 ((134)Cs), -137 ((137)Cs), and natural radionuclide potassium-40 ((40)K) by γ-ray spectroscopy. Dietary intake of radioactive cesium around Fukushima area was somewhat higher than in other areas. However, maximum committed effective doses obtained by the market basket and duplicate diet samples were 0.0094 and 0.027 mSv/year, respectively, which are much lower than the maximum permissible dose (1 mSv/year) in foods in Japan.

Characterization of natural aryl hydrocarbon receptor agonists from cassia seed and rosemary

Many recent studies have suggested that activation of the aryl hydrocarbon receptor (AhR) reduces immune responses, thus suppressing allergies and autoimmune diseases. In our continuing study on natural AhR agonists in foods, we examined the influence of 37 health food materials on the AhR using a reporter gene assay, and found that aqueous ethanol extracts of cassia seed and rosemary had particularly high AhR activity. To characterize the AhR-activating substances in these samples, the chemical constituents of the respective extracts were identified. From an active ethyl acetate fraction of the cassia seed extract, eight aromatic compounds were isolated. Among these compounds, aurantio-obtusin, an anthraquinone, elicited marked AhR activation. Chromatographic separation of an active ethyl acetate fraction of the rosemary extract gave nine compounds. Among these compounds, cirsimaritin induced AhR activity at 10-10² μM, and nepitrin and homoplantagenin, which are flavone glucosides, showed marked AhR activation at 10-10³ μM.

[Reduction of radioactive cesium content in pond smelt by cooking]

In Japan, seafood may be eaten raw or after having been cooked in diverse ways. Therefore, it is important to understand the effect of cooking on the extent of contamination with radioactive materials in order to avoid internal exposure to radioactive materials via seafood. In this study, we investigated the changes in radioactive cesium content in pond smelt cooked in four different ways: grilled, stewed (kanroni), fried and soaked (nanbanzuke). The radioactive cesium content in grilled, kanroni and fried pond smelt was almost unchanged compared with the uncooked state. In contrast, radioactive cesium content in nanbanzuke pond smelt was decreased by about 30%. Our result suggests that soaking cooked pond smelt in seasoning is an effective method of reducing the burden radioactive cesium.

[Reduction of radioactive cesium content in beef by soaking in seasoning]

It is important to obtain information about ways of removing radioactive cesium from foods in order to reduce internal radiation exposure from food and to ensure the safety and security of food. In this study, we investigated the change of radioactive cesium content in beef due to soaking in seasoning. Our results revealed that soaking beef in liquid seasoning (salt concentration: 8-10%) for 24 h or in miso seasoning (salt concentration: about 9%) for 7 days decreased the radioactive cesium content by about 20% and 55%, respectively, compared with that present in beef before soaking. Furthermore, soaking beef in 10% salt solution for 7 days while changing the salt solution every day or every three days decreased the radioactive cesium content by about 75%, compared with that present in beef before soaking. Because the seasoning is usually discarded after soaking, the procedure of soaking beef in seasoning is a useful method of reducing the burden of radioactive cesium.

[Application of electron spin resonance spectroscopy for the detection of irradiated crustaceans (prawn, shrimp, and crabs)]

Prawn, shrimp and crabs sold in Japan are mostly imported from overseas. Detection of irradiated crustaceans is very important for quality assurance. In this study, we used ESR to detect radiation-induced radicals after irradiation of prawn, shrimp and crabs of major species. No radiation-induced radicals were detected in prawn (black tiger prawn) or shrimp (white leg shrimp). Radiation-induced radicals due to hydroxyapatite were detected in the claws of snow crab, red king crab, and swimming crab. Our results indicate that ESR measurement on the claw parts of these three species of crab can be used to determine their irradiation history.

[Estimation of the committed effective dose of radioactive cesium and potassium by the market basket method]

The Tokyo Electric Power Company's Fukushima Daiichi nuclear power plant disaster after the Great East Japan Earthquake has caused radioactive contamination in food. Using the market basket method, total diet samples in Tokyo, Miyagi prefecture and Fukushima prefecture were analyzed for cesium-134 and -137 (radioactive cesium) and naturally occurring potassium-40 (radioactive potassium) in order to estimate the committed effective doses of these radioactive materials from food. Doses were calculated on the assumption that "not detected" corresponded to zero or to half the limit of detection (values in brackets). The estimated doses of radioactive cesium in Tokyo, Miyagi and Fukushima were 0.0021 (0.0024), 0.017 (0.018) and 0.019 (0.019) mSv/year, respectively. Although the doses in Miyagi and Fukushima were more than 8 times the dose in Tokyo, they were significantly lower than the maximum permissible dose (1 mSv/year) determined by the Ministry of Health, Labour and Welfare, Japan. The estimated doses of naturally occurring radioactive potassium in these areas were in the range of 0.17-0.20 (0.18-0.20) mSv/year, and there were no significant differences between the areas.

[Evaluation of an analytical method for cyanogenic compounds in bean paste and its application for surveillance of real samples]

In order to ensure compliance of raw bean paste products with the Japanese Food Sanitation Law, we examined the performance characteristics of an analytic procedure based on steam distillation followed by carbonate-pyrazolone assay to determine cyanogenic compounds in raw bean paste. The present method includes a procedure for decomposition cyanogenic glycosides using linamarase due to the possibility that cyanogenic glycoside-hydrolyzing enzymes might be deactivated in raw bean pastes. The performance of the method was evaluated using two types of bean paste spiked with a cyanogenic glycoside (linamarin) corresponding to cyanide ion concentrations of 5 and 10 mg/kg. The trueness of the method was 86-90%, and the repeatability (RSD) was 1.0-2.4%, while the intermediate precision (RSD) was 2.6% to 4.9%. A surveillance of cyanogenic compounds in 28 raw bean pastes manufactured in Japan was then carried out with the validated method. One sample contained 15 mg/kg (as hydrogen cyanide), while the other samples contained less than 5 mg/kg.

[Surveillance of radioactive cesium in foods]

We surveyed foods on the market from areas that had been exposed to radioactive materials contamination following the Fukushima accident. We used a NaI (Tl) scintillation spectrometer for the screening tests and a germanium semiconductor detector for the final tests. Test results from 1,427 samples showed that 6 samples (0.4%) exceeded the regulatory limit of 500 Bq/kg. Considering the detection rate of radioactive cesium in each food category, we suggest that it is necessary to continue monitoring fruits such as chestnuts and ginkgo nuts, mushrooms (especially raw wood-shiitake), mountain vegetables, and sea fish.

Hyperocclusion Up-regulates CCL3 Expression in CCL2- and CCR2-deficient Mice

Excessive mechanical stress (MS) during hyperocclusion is known to result in disappearance of the alveolar hard line, enlargement of the periodontal ligament (PDL) space, and destruction of alveolar bone, leading to occlusal traumatism. We have recently reported that MS induces predominantly C-C chemokine ligand (CCL) 2 expression in PDL tissues, leading, via C-C chemokine receptor (CCR) 2, to MS-dependent osteoclastogenesis in alveolar bone. Thus, we hypothesize that ablation of the CCL2/CCR2 signaling pathway should suppress MS-induced osteoclastogenesis-associated chemokines and alleviate occlusal traumatism. We examined the effect of MS on chemokine expression and osteoclastogenesis using in vivo and in vitro hyperocclusion models with CCL2-deficient (CCL2(-/-)) and CCR2-deficient (CCR2(-/-)) mice. Compared with that in wild-type mice, expression of CCL3 in PDL cells and TRAP-positive cells in alveolar bone from CCL2(-/-) and CCR2(-/-) mice was up-regulated, even in the absence of MS. Furthermore, the expression of CCL3 and TRAP-positive cells was significantly increased after both 4 and 7 days of hyperocclusal MS loading in CCL2(-/-) and CCR2(-/-) mice. Hyperocclusion induced compensatory CCL3 expression and promoted osteoclastogenesis to counterbalance deficient CCL2/CCR2 signaling, suggesting that co-expression of CCL3 with CCL2 may precipitate synergistic, MS-dependent alveolar bone destruction during occlusal traumatism. Abbreviations: MS, mechanical stress; PDL, periodontal ligament; CCL2, CC chemokine ligand 2 (MCP-1; monocyte chemoattractant protein-1); CCR2, CC chemokine receptor 2; CCL3, CC chemokine ligand 3 (MIP-1α); CCL5, CC chemokine ligand 5 (RANTES).

Evaluation of an analytical method for cyanogenic compounds in beans and surveillance of cyanogenic compounds in beans

The performance characteristics of an analytical method for cyanogenic compounds were evaluated. Specifically, we tested the trueness, repeatability and intermediate precision of the method using a spectrophotometric-based detection system for 4-pyridinecarboxylic acid and pyrazolone after steam distillation. The pH adjustment of the distillate was revealed to affect the trueness of the measurements. A pH of approximately 6 was found to be optimal. The targeted quantitation limit of the cyanide ion was set to 5 mg/kg. The performance of the method was evaluated using beans spiked with cyanide ion at one to two times the quantitation limit (5-10 mg/kg). The trueness of the method was between 78-90%, and the repeatability and intermediate precision were between RSD 1.2% to 6.0%. A surveillance of cyanogenic compounds in beans retailed in Japan was then carried out. All the results were below the quantitation limit of 5 mg/kg.

Third-generation Ah receptor-responsive luciferase reporter plasmids: amplification of dioxin-responsive elements dramatically increases CALUX bioassay sensitivity and responsiveness

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD, dioxin) and related dioxin-like chemicals are widespread and persistent environmental contaminants that produce diverse toxic and biological effects through their ability to bind to and activate the Ah receptor (AhR) and AhR-dependent gene expression. The chemically activated luciferase expression (CALUX) system is an AhR-responsive recombinant luciferase reporter gene-based cell bioassay that has been used in combination with chemical extraction and cleanup methods for the relatively rapid and inexpensive detection and relative quantitation of dioxin and dioxin-like chemicals in a wide variety of sample matrices. Although the CALUX bioassay has been validated and used extensively for screening purposes, it has some limitations when screening samples with very low levels of dioxin-like chemicals or when there is only a small amount of sample matrix for analysis. Here, we describe the development of third-generation (G3) CALUX plasmids with increased numbers of dioxin-responsive elements, and stable transfection of these new plasmids into mouse hepatoma (Hepa1c1c7) cells has produced novel amplified G3 CALUX cell bioassays that respond to TCDD with a dramatically increased magnitude of luciferase induction and significantly lower minimal detection limit than existing CALUX-type cell lines. The new G3 CALUX cell lines provide a highly responsive and sensitive bioassay system for the detection and relative quantitation of very low levels of dioxin-like chemicals in sample extracts.

Determination of dioxin concentrations in fish and seafood samples using a highly sensitive reporter cell line, DR-EcoScreen cells

There is a strong need for the development of relatively rapid and low-cost bioassays for the determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in environmental and food samples. In this study, we applied a reporter gene assay using DR-EcoScreen cells (DR-cell assay), which is highly sensitive to dioxins, to the determination of PCDD/Fs and dl-PCBs in fish and seafood samples. The PCDD/Fs and dl-PCBs were extracted from homogenated samples (10 g) of 30 fish and shellfish, purified by clean-up procedure using a multilayered silica gel column and an alumina column, and applied to DR-cell assay. Interestingly, the bioanalytical equivalent (BEQ) values obtained from the DR-cell assay [<0.1∼5.4 pg BEQ g(-1) wet weight (ww)] were closely correlated with the toxicity equivalent (TEQ) values from conventional high-resolution gas chromatography/high-resolution mass spectrometry (HRGC-HRMS) analysis (r(2)=0.912), and the slope of regression line was 0.913. Therefore, we multiplied the BEQ values from the DR-cell assay by a conversion coefficient (1.095, the reciprocal of 0.913) to approximate the TEQ values from the HRGC-HRMS analysis. Furthermore, we used this DR-cell assay to perform a prescreening test of PCDD/Fs and dl-PCBs in 16 fish and seafood samples purchased from a supermarket, revealing that a sample from the fatty flesh of a bluefin tuna exceeded 8 pg TEQ g(-1)ww (the European Union-tolerance limit). Taken together, these results suggest that the DR-cell assay might be applicable as a rapid and low-cost prescreening method to determine dioxin levels in fish and seafood samples.

[Correlation of fat content and dioxins, total mercury and methyl mercury levels in tuna]

In this study, we analyzed the concentrations of mercury and dioxins in tuna with various fat contents (akami; the leaner meat, Chutoro; the belly area of the tuna along the side of the fish between the akami and the otoro. Otoro; the fattiest portion of the tuna) in wild and farmed bluefin tuna and farmed southern bluefin tuna. In the three kinds of tuna, average dioxins concentrations in Akami, chutoro and otoro were 1.7, 4.7 and 9.6 pg TEQ/g, respectively. The dioxins concentration in all three regions of tuna was in direct proportion to the fat content. In the farmed bluefin tuna, the dioxins concentration was almost the same as that of the wild tuna, but differed from that of the farmed southern bluefin tuna. Average total mercury concentration based on wet weight in akami was 0.42 µg/g, being higher than the values of 0.36 µg/g of chutoro and 0.31 µg/g of otoro, and in inverse proportion to the fat content. In all three regions, the total mercury concentration of the wild bluefin tuna was equal to that of the farmed tuna. The total mercury concentration in the latter was two to three times higher than that of the farmed southern bluefin tuna. If the Japanese intake is one fin of tuna (80 g) a day, the daily intake levels of dioxins and methyl mercury can be estimated as 0.48-37 pg TEQ/kg bw and 0.21-0.90 µg/kg bw, respectively.