GC-MS Analysis of Primary Aromatic Amines Originated From Azo Dyes in Commercial Textile or Leather Products Using Helium Alternative Carrier Gases

BACKGROUND

In recent years, due to the global shortage of helium gas, the development of gas chromatography (GC) analytical methods using alternatives to helium carrier gases is necessary.

OBJECTIVE

The objective of this study was to examine the applicability of hydrogen and nitrogen as alternative carrier gases using the test method for azo compounds in the Act on Control of Household Products Containing Harmful Substances of Japan.

METHOD

The gas chromatograph mass spectrometer (GC-MS) analytical method using hydrogen and nitrogen as alternative carrier gases was compared with a method using helium for 26 primary aromatic amines (PAAs) originated from azo dyes.

RESULTS

When hydrogen and nitrogen were used as carrier gases under the same conditions used during analysis using helium (same column, gas flow rate, oven temperature conditions, etc.), sufficient peak separation of 26 PAAs was obtained. The sensitivities of the methods using helium and hydrogen were comparable, whereas the sensitivity was lower when nitrogen was used, with the detection limits ranging from 1/220 to 1/25. However, all carrier gases achieved quantification at concentrations below the standard value (30 μg/g) of the Act on Control of Household Products Containing Harmful Substances, and the results were in agreement with the standard value for the target product.

CONCLUSIONS

Our results indicated that hydrogen or nitrogen can be used as alternative carrier gases to helium for GC-MS analysis of azo compounds producing specific aromatic amines.

HIGHLIGHTS

Using hydrogen or nitrogen as an alternative carrier gas to helium, azo compounds could be quantified with excellent accuracy.

[Examination of Analytical Method for Tris(2,3-dibromopropyl)phosphate and Bis(2,3-dibromopropyl)phosphate to Revise the Official Methods Based on "Act on the Control of Household Products Containing Harmful Substances"]

In Japan, the use of frame retardants [tris(2,3-dibromopropyl)phosphate: TDBPP and bis(2,3-dibromopropyl)phosphate: BDBPP] in several household textile products is banned under the "Act on the Control of Household Products Containing Harmful Substances." As the official analytical methods for testing these substances have not been revised for over 42 years, several issues such as the using of harmful reagents, have been pointed out. Therefore, we developed a new method to revise the official method in our previous study. In this study, the validity of the developed test method is evaluated at six laboratories using two types of textile samples spiked with TDBPP and BDBPP at three concentrations (4, 8, and 20 µg/g). TDBPP and BDBPP are extracted under reflux using methanol containing hydrochloric acid. TDBPP is analyzed using GC-MS, and BDBPP is also analyzed using GC-MS after methylation with trimethylsilyl diazomethane. Although the accuracy (70-120%), repeatability (<10%), and reproducibility (<15%) of a few samples, mainly low concentration samples, are out of range, overall, the concentration level of detection limits of TDBPP and BDBPP (8 and 10 µg/g) in official analytical methods are quantifiable with sufficient precision using the proposed method. Furthermore, harmful reagents are not used in this method. Thus, the method validated in this study is effective as a revised method for the testing of TDBPP and BDBPP in household textile products.

Analysis of patch testing with cocamidopropyl betaine and its impurities in patients with intractable scalp dermatitis in a single clinic in Japan

BACKGROUND

The allergen responsible for cocamidopropyl betaine (CAPB) allergies has been debated.

OBJECTIVES

To investigate the sensitizing agents of CAPB, the patch test positivity rates of impurities were examined in Japanese patients with CAPB-related allergic contact dermatitis.

MATERIALS AND METHODS

Thirty patients with scalp dermatitis and positive patch tests for CAPB and/or lauramidopropyl betaine (LAPB) were enrolled in this study. They were patch tested with the detergents that they had been using at the time of their first visit and with the impurities dimethylaminopropylamine (DMAPA) and lauramidopropyl dimethylamine (LAPDMA).

RESULTS

The positivity rate in patch tests of the 37 detergents that the patients had been using was 78.4% (29/37). The positivity rates of DMAPA 1% pet., 1% aq. and 0.2% aq. were 32.1% (9/28), 14.3% (4/28) and 13.3% (4/30), respectively, whereas those of LAPDMA 0.1% and 0.05% were 30.0% (9/30) and 16.7% (5/30), respectively. Among the 30 patients, 6 exhibited positive results for both DMAPA and LAPDMA, 3 showed positive results for DMAPA alone and 6 produced positive results for LAPDMA alone.

CONCLUSION

Patch tests produced an overall positivity rate for DMAPA, LAPDMA or both of 50.0% (15/30) in patients with scalp dermatitis and positive patch test results for CAPB and/or LAPB.

A step-by-step approach for assessing acute oral toxicity without animal testing for additives of quasi-drugs and cosmetic ingredients

Animal testing of cosmetic ingredients and products has been banned in the European Union since 2013. However, in Japan, the application of new quasi-drugs requires the generation of data on acute oral toxicity through animal testing. A weight of evidence approach for assessing oral toxicity was challenged. This approach used a combination of safety data, including a neutral red uptake cytotoxicity assay using BALB/c3T3 cells (3T3-NRU cytotoxicity assay), which can assess the acute oral toxicity of quasi-drugs or cosmetic ingredients. We conclude that the step-by-step approach can be used to assess test substances that cause low acute oral toxicity, such as the median lethal dose (LD 50) > 2000 mg/kg, thereby avoiding animal testing.

Determination of Carcinogenic Primary Aromatic Amines Contained as Impurities in Synthetic Organic Colorants

BACKGROUND

Several primary aromatic amines (PAAs) have been designated carcinogenic or suspected of carcinogenicity. Several kinds of PAAs may occur either via the reduction of azo compounds or as impurities in azo colorants or other agents.

OBJECTIVE

An analytical method was developed and applied to determine whether certain PAAs are present as impurities in synthetic organic colorants.

METHOD

Target chemicals were analyzed by the ultrasound extraction of the synthetic organic colorant with a hydrochloric acid solution containing 20% methanol, followed by conversion from an acidic to alkaline solution, and then extraction using a diatomaceous earth column.

RESULTS

We analyzed certain PAAs in 38 synthetic organic colorants, resulting in the detection of 2,4-dimethylaniline in four samples at 1.2 to 19 μg/g, o-toluidine in three samples at 1.0 to 3.4 μg/g, p-phenylazoaniline in two samples at 74 to 305 μg/g, and, in one sample each, 2,4,5-trimethylaniline (13 μg/g), 5-nitro-o-toluidine (12 μg/g), and 2-methyl-4-(2-tolylazo)aniline (13 μg/g). Nearly all PAAs were determined to be starting materials for colorant synthesis, although p-phenylazoaniline in Yellow No. 407 was apparently a byproduct formed during synthesis. For Red No. 225, in which high concentrations of p-phenylazoaniline were detected, additional samples were purchased from five companies, and p-phenylazoaniline was detected at concentrations of 88 to 370 μg/g in all samples.

CONCLUSIONS

A method to analyze certain PAAs contained as impurities in synthetic organic colorants was developed, and the actual status of them in colorants was clarified.

HIGHLIGHTS

The analytical method developed in this study for the determination of certain PAAs contained as impurities in synthetic organic colorants may be used to improve the safety of colorants.

Oral Exposure to Lead Acetate for 28 Days Reduces the Number of Neural Progenitor Cells but Increases the Number and Synaptic Plasticity of Newborn Granule Cells in Adult Hippocampal Neurogenesis of Young-Adult Rats

Lead (Pb) causes developmental neurotoxicity. Developmental exposure to Pb acetate (PbAc) induces aberrant hippocampal neurogenesis by increasing or decreasing neural progenitor cell (NPC) subpopulations in the dentate gyrus (DG) of rats. To investigate whether hippocampal neurogenesis is similarly affected by PbAc exposure in a general toxicity study, 5-week-old Sprague-Dawley rats were orally administered PbAc at 0, 4000, and 8000 ppm (w/v) in drinking water for 28 days. After exposure to 4000 or 8000 ppm PbAc, Pb had accumulated in the brains. Neurogenesis was suppressed by 8000 ppm PbAc, which was related to decreased number of type-2b NPCs, although number of mature granule cells were increased by both PbAc doses. Gene expression in the 8000 ppm PbAc group suggested suppressed NPC proliferation and increased apoptosis resulting in suppressed neurogenesis. PbAc exposure increased numbers of metallothionein-I/II⁺ cells and GFAP⁺ astrocytes in the DG hilus, and upregulated Mt1, antioxidant genes (Hmox1 and Gsta5), and Il6 in the DG, suggesting the induction of oxidative stress and neuroinflammation related to Pb accumulation resulting in suppressed neurogenesis. PbAc at 8000 ppm also upregulated Ntrk2 and increased the number of CALB2⁺ interneurons, suggesting the activation of BDNF-TrkB signaling and CALB2⁺ interneuron-mediated signals to ameliorate suppressed neurogenesis resulting in increased number of newborn granule cells. PbAc at both doses increased the number of ARC⁺ granule cells, suggesting the facilitation of synaptic plasticity of newborn granule cells through the activation of BDNF-TrkB signaling. These results suggest that PbAc exposure during the young-adult stage disrupted hippocampal neurogenesis, which had a different pattern from developmental exposure to PbAc. However, the induction of oxidative stress/neuroinflammation and activation of identical cellular signals occurred irrespective of the life stage at PbAc exposure.

A cell-based evaluation of human tyrosinase-mediated metabolic activation of leukoderma-inducing phenolic compounds

BACKGROUND

Chemical leukoderma is a skin depigmentation disorder induced through contact with certain chemicals, most of which have a p-substituted phenol structure similar to the melanin precursor tyrosine. The tyrosinase-catalyzed oxidation of phenols to highly reactive o-quinone metabolites is a critical step in inducing leukoderma through the production of melanocyte-specific damage and immunological responses.

OBJECTIVE

Our aim was to find an effective method to evaluate the formation of o-quinone by human tyrosinase and subsequent cellular reactions.

METHODS

Human tyrosinase-expressing 293T cells were exposed to various phenolic compounds, after which the reactive o-quinones generated were identified as adducts of cellular thiols. We further examined whether the o-quinone formation induces reductions in cellular GSH or viability.

RESULTS

Among the chemicals tested, all 7 leukoderma-inducing phenols/catechol (rhododendrol, raspberry ketone, monobenzone, 4-tert-butylphenol, 4-tert-butylcatechol, 4-S-cysteaminylphenol and p-cresol) were oxidized to o-quinone metabolites and were detected as adducts of cellular glutathione and cysteine, leading to cellular glutathione reduction, whereas 2-S-cysteaminylphenol and 4-n-butylresorcinol were not. In vitro analysis using a soluble variant of human tyrosinase revealed a similar substrate-specificity. Some leukoderma-inducing phenols exhibited tyrosinase-dependent cytotoxicity in this cell model and in B16BL6 melanoma cells where tyrosinase expression was effectively modulated by siRNA knockdown.

CONCLUSION

We developed a cell-based metabolite analytical method to detect human tyrosinase-catalyzed formation of o-quinone from phenolic compounds by analyzing their thiol-adducts. The detailed analysis of each metabolite was superior in sensitivity and specificity compared to cytotoxicity assays for detecting known leukoderma-inducing phenols, providing an effective strategy for safety evaluation of chemicals.

Characterization of synthetic turf rubber granule infill in Japan: Total content and migration of metals

We evaluated the total content of 28 metals in synthetic turf rubber granule infill and performed extraction tests using four types of simulated biofluids to assess the health effects of synthetic turf crumb rubbers used in Japan. The highest median metal concentration was obtained for Zn, with median concentrations above 100 μg/g, followed by Al, Fe, and Mn. The highest median Pb concentration was 19.9 μg/g. The metal concentrations of the samples were different depending on the origin/material. Among high-concentration metals, Al, Fe, and Mn were higher in ethylene propylene diene monomer rubber, and Zn was higher in tires. Significantly higher Sb and Sr concentrations were observed in other materials, including industrial rubber, synthetic rubber, and thermoplastic elastomer, compared with tires. However, significantly higher Sn, Co, Pb, and Cd concentrations were detected in tires compared with other materials. Metals with high concentrations independent of the origin/material were considered derived from materials added during the manufacturing process. To evaluate the bioaccessibility, extraction tests were conducted using simulated biofluids. In gastric fluid, many metals were detected in higher concentrations than in other biofluids, intestinal fluid, saliva, and sweat, and the extraction rate of most metals exceeded 10% in artificial gastric fluid. Because the amount of metals leached into the simulated biofluids was much lower than several standards on the amount of certain metals that have the potential to be extracted from the object if ingested, the risk related to the exposure to metals from synthetic turf rubber granule infill is considered low.

Characterization of synthetic turf rubber granule infill in Japan: Polyaromatic hydrocarbons and related compounds

Although the health effects of artificial turf fillings have been investigated in Europe and the United States, the actual situation in Japan is unclear. To address this issue, the concentrations of 46 polyaromatic hydrocarbons (PAHs) and related compounds in rubber infills were analyzed prior to their use in synthetic turf fields in Japan. Based on information obtained from the sample suppliers, the investigated samples were divided into five categories: discarded tires, industrial rubber, combinations of these products or unidentified components (mixture/unknown), synthetic rubber specifically manufactured for synthetic turf, and special-purpose thermoplastic elastomers (TPEs). The industrial rubber samples were mixtures of styrene butadiene rubber, natural rubber, and ethylene propylene diene rubber (EPDM). The synthetic rubber samples consisted only of EPDM. A few or none of the PAHs were detected in the synthetic rubber and TPE samples. However, in the discarded tire and industrial rubber samples, benzo[a]pyrene, cyclopenta[cd]pyrene, and 30 other compounds were detected. A comparison between these two categories indicated that the discarded tire samples exhibited higher concentrations of the target compounds than the industrial rubber samples. This finding can be attributed to the presence of EPDM in almost all of the industrial rubber samples, which were not present in the discarded tire samples. The maximum PAH concentrations obtained in the present study were equivalent to or lower than the previously reported PAH concentrations. The total concentrations of the eight PAHs included in the European Chemical Agency (ECHA) assessment of health risks were lower in the present study than those reported by the ECHA. Furthermore, elution testing was performed with four simulated biofluids (gastric and intestinal juices, saliva, and perspiration). The actual elution amounts of all compounds were less than the limits. This report provides basic data for the risk assessment of PAHs in rubber infills.

Characterization of synthetic turf rubber granule infill in Japan: Rubber additives and related compounds

We have conducted several studies with an overall goal of assessing the effects of rubber granules in synthetic turf on the health of athletes, other players, and children in Japan. As part of these studies, the investigation reported herein was aimed at analyzing the concentrations of rubber additives (vulcanization accelerators, antioxidants, and cross-linking agents) and related chemicals in 46 rubber infills prior to their use in synthetic turf fields in Japan. Of the 36 chemicals selected for targeted analysis, 26 were detected and quantified. Nontargeted analyses further identified and quantified 16 compounds derived from vulcanization accelerators, plasticizers, and other additives. The types and concentrations of the detected compounds varied both between products and within the same product; in the case of rubber infill products made from recycled rubber, this variation was caused by the different types of rubber products recycled as raw materials. Elution tests with four simulated biofluids (gastric juice, intestinal juice, saliva, and perspiration) revealed that the elution rates varied between compounds and were affected by the presence of coatings. Most compounds had low elution rates in all the simulated biofluids, with many at or below the limit of quantification. The data reported herein will be utilized in the risk characterization part of our subsequent study on the health risk assessment of rubber infill.

Characterization of synthetic turf rubber granule infill in Japan: Volatile organic compounds

There has been extensive studies on the composition of tires and industrial rubber. However, there is insufficient information on volatile organic compounds (VOCs) emitted from rubber granule products used to fill synthetic turf fields. In this study, we applied a passive sampling method for assessing the VOCs emitted from rubber granule products used for filling synthetic turf fields. We also performed a quantitative component analysis using a gas chromatography-mass spectrometer (GC-MS). The component analysis results of 46 rubber granule-based products showed the predominant presence of benzothiazole and methyl isobutyl ketone. The level of benzene, which the International Agency for Research on Cancer classifies as a substance with sufficient evidence for carcinogenicity to humans, was below the lower quantification limit in the products tested in this study. Our study included most of the rubber granule products used for synthetic turf fields in Japan (>95% of the products in the current domestic market of Japan). Therefore, we obtained a comprehensive overview of the VOCs emitted from the rubber granule-based products used in Japan's synthetic turf fields. Estimating the exposure to these airborne VOCs is essential to evaluate the adverse health effects of the VOCs emitted from these rubber granule-based products. Our sampling method and results can help provide key data for such risk assessment studies in the future.

[Investigation of Foreign Particles in Moderna COVID-19 Vaccine]

Particular batches of Moderna mRNA Coronavirus Disease 2019 (COVID-19) vaccine were recalled after foreign particles were found in some vaccine vials at the vaccination site in Japan in August 2021. We investigated the foreign particles at the request of the Ministry of Health, Labour and Welfare. Energy dispersive X-ray spectroscopy analysis suggested that the foreign particles found in the vials recalled from the vaccination sites were from stainless steel SUS 316L, which was in line with the findings of the root cause investigation by the manufacturer. The sizes of the observed particles ranged from <50 μm to 548 μm in the major axis. Similar foreign particles were also detected in 2 of the 5 vaccine vials of the same lot stored by the manufacturer, indicating that the foreign particles have already been administered to some people via vaccine. Observation of the vials of the same lot by digital microscope found smaller particles those were not detected by visual inspection, suggesting that more vials were affected. Contrarily, visual inspection and subvisible particulate matter test indicated no foreign particles in the vials of normal lots. Possible root cause and strategies to prevent such a deviation were discussed from technical and regulatory aspects.

Free formaldehyde in non-medical face masks purchased from the Japanese market since the COVID-19 outbreak

Since the Coronavirus Disease 2019 (COVID-19) pandemic began, people have been wearing face masks for many hours every day. As these face masks are in contact with the skin, it is important to pay more attention to their quality and safety. This study examined the concentration of free formaldehyde in 90 non-medical face masks and related products (33 nonwoven, 30 woven cloth, 12 polyurethane, and 15 related products) because formaldehyde is a common contact allergen in textile products. For products consisting of mixed materials, each material was sampled, resulting in 103 samples for analysis. Free formaldehyde (34-239 μg/g) was found in three cloth masks, which consisted of cotton and polyester, with antibacterial and antiviral labeling. It was confirmed that the detected formaldehyde originated from the mask-finishing treatment by a hydrochloric acid extraction discrimination test. These masks may elicit contact dermatitis if the consumers have already been sensitized to formaldehyde. However, the risk of contact dermatitis caused by formaldehyde in masks may be considered low since the frequency of formaldehyde detection in masks in Japan is low.

Induction of cellular senescence as a late effect and BDNF-TrkB signaling-mediated ameliorating effect on disruption of hippocampal neurogenesis after developmental exposure to lead acetate in rats

Lead (Pb) exposure causes cognitive deficits in children. The present study investigated the effect of developmental exposure to Pb acetate (PbAc) on postnatal hippocampal neurogenesis. Pregnant rats were administered drinking water containing 0, 2000, or 4000 ppm PbAc from gestational day 6 until day 21 post-delivery (weaning), and offspring were maintained without PbAc exposure until adulthood on postnatal day (PND) 77. There was a dose-related accumulation of Pb in the offspring brain at weaning, while Pb was mainly excreted in adulthood. In the hippocampus, metallothionein I/II immunoreactive ⁽⁺⁾ glia were increased through adulthood as a neuroprotective response to accumulated Pb, accompanied by increased astrocyte and microglia numbers in adulthood, suggesting sustained neural damage. Gene expression changes suggested elevated oxidative stress at weaning and suppression of the antioxidant system in adulthood, as well as continued neuroinflammatory responses. At weaning, granule cell apoptosis was increased and numbers of type-3 neural progenitor cells (NPCs) were decreased. By contrast, type-2a and type-2b NPCs were increased, suggesting suppressed differentiation to type-3 NPCs. In adulthood, there were increased numbers of immature granule cells. In the hilus of the dentate gyrus, somatostatin⁺ interneurons were increased at weaning, while calbindin-D-29K⁺ interneurons were increased throughout adulthood, suggesting a strengthened interneuron regulatory system against the suppressed differentiation at weaning. In the dentate gyrus, Bdnf, Ntrk2, and Chrna7 gene expression were upregulated and numbers of hilar TrkB⁺ interneurons increased at weaning. These findings suggest activation of BDNF-TrkB signaling to increase somatostatin⁺ interneurons and promote cholinergic signaling, thus increasing later production of immature granule cells. In adulthood, Pcna and Apex1 gene expression were downregulated and Chek1 and cyclin-dependent kinase inhibitor expression were upregulated. Furthermore, there was an increase in γ-H2AX⁺ SGZ cells, suggesting induction of cellular senescence of SGZ cells due to Pb genotoxicity.

[Examination of Analytical Methods for Methanol, Trichloroethylene, and Tetrachloroethylene to Revise the Official Methods Based on the Act on the Control of Household Products Containing Harmful Substances]

In Japan, the use of methanol, trichloroethylene, and tetrachloroethylene in aerosol household products is banned under the Act on the Control of Household Products Containing Harmful Substances. As the official analytical methods for testing for these substances have not been revised for over 35 years, several issues have been pointed out. Thus, we developed a new method to revise the official method in our previous study. In this study, validation of the proposed method for detecting the target substances was conducted using two aerosol-product samples (A and B), which contained methanol, trichloroethylene, and tetrachloroethylene. Sample A comprised regulated values of these compounds, while sample B comprised one-tenth of the regulated amounts. They also contained several volatile compounds that served as interfering substances. Subsequently, the samples were analyzed using head space/gas chromatography-mass spectrometry, and it was confirmed that the three target substances were separated from the other chemicals on chromatograms. Validation tests were conducted at seven laboratories to evaluate the proposed method using the prepared samples. In one laboratory, the recovery of trichloroethylene and tetrachloroethylene in sample B was slightly higher at 120%, while the recoveries obtained from the other tests were between 70% and 120%. Relative standard deviation at each laboratory was less than 10%. Furthermore, the relative standard deviations between the validation tests with respect to each chemical were less than 15%. Therefore, the method validated in this study was considered to be effective as a revised method for testing for methanol, trichloroethylene, and trichloroethylene in household aerosol products.

Evaluation of the sensitization potential of volatile and semi-volatile organic compounds using the direct peptide reactivity assay

The purpose of this study was to evaluate the sensitization potential of 82 compounds classified as volatile and/or semi-volatile organic compounds using the direct peptide reactivity assay (DPRA), given that these chemical compounds have been detected frequently and at high concentrations in a national survey of Japanese indoor air pollution and other studies. The skin sensitization potential of 81 of these compounds was evaluable in our study; one compound co-eluted with cysteine peptide and was therefore not evaluable. Twenty-five of the evaluated compounds were classified as positive. Although all glycols and plasticizers detected frequently and at high concentrations in a national survey of Japanese indoor air pollution were negative, hexanal and nonanal, which are found in fragrances and building materials, tested positive. Monoethanolamine and 1,3-butanediol, which cause clinical contact dermatitis, and several compounds reported to have weak sensitization potential in animal studies, were classified as negative. Thus, it was considered that compounds with weak sensitization potential were evaluated as negative in the DPRA. Although the sensitization potential of the formaldehyde-releasing preservative bronopol has been attributed to the release of formaldehyde (a well-known contact allergen) by its degradation, its degradation products-bromonitromethane and 2-bromoethanol-were classified as positive, indicating that these degradation products also exhibit sensitization potential. The compounds that tested positive in this study should be comprehensively assessed through multiple toxicity and epidemiological studies.

[Ensuring Traceability Using qNMR in the Quantitative Analysis of Formaldehyde and Acetaldehyde]

　Currently, indoor air quality guidelines for formaldehyde and acetaldehyde are set by the Ministry of Health, Labour and Welfare of Japan. Aldehydes are widely used in adhesives and preservatives, and exposure to these compounds via indoor air is a matter of concern. Considering that contact with indoor air is part of daily life, evaluation of indoor air quality is extremely important. 2,4-Dinitrophenylhydrazine (DNPH) derivatization is widely used for quantitative analysis of aldehydes. A certified reference material with traceability to the International System of Units (SI) is required for this method. However, currently, there are no certified reference materials available for aldehyde-DNPH derivatives, which means that the quantified values obtained by this method are not sufficiently reliable. In this study, we determined the actual content and purity of commercially available aldehyde-DNPH derivatives using ¹H-quantitative NMR (qNMR), which can be measured with SI-traceability. Although the commercial DNPH derivatives of formaldehyde and acetaldehyde were low concentration solutions, we were able to determine their purities using ¹H-qNMR. Furthermore, we were able to separate and quantify the acetaldehyde isomers generated by the derivatization reaction. In conclusion, it is possible to obtain highly accurate results using ¹H-qNMR with commercially available reagents that are not certified metrologically.

Increase of β2-integrin on adhesion of THP-1 cells to collagen vitrigel membrane

When human monocyte-derived leukemia (THP-1) cells, which are floating cells, are stimulated with lipid peroxides, or Streptococcus suis, these cells adhere to a plastic plate or endothelial cells. However, it is unclear whether or not non-stimulated THP-1 cells adhere to collagen vitrigel membrane (CVM). In this study, firstly, we investigated the rate of adhesion of THP-1 cells to CVM. When THP-1 cells were not stimulated, the rate of adhesion to CVM was high. Then, to identify adhesion molecules involved in adhesion of THP-1 cells to CVM, expressions of various cell adhesion molecules on the surface of THP-1 cells adhering to CVM were measured. β-actin, β-catenin, and β1-integrin expressions did not change in non-stimulated THP-1 cells cultured on CVM compared with those in cells cultured in a flask, but β2-integrin expression markedly increased.

Titanium dioxide nanoparticles exacerbate pneumonia in respiratory syncytial virus (RSV)-infected mice

To reveal the effects of TiO2 nanoparticles, used in cosmetics and building materials, on the immune response, a respiratory syncytial virus (RSV) infection mouse model was used. BALB/c mice were exposed once intranasally to TiO2 at 0.5mg/kg and infected intranasally with RSV five days later. The levels of IFN-γ and chemokine CCL5, representative markers of pneumonia, in the bronchoalveolar lavage fluids of RSV-infected mice had increased significantly in TiO2-exposed mice compared with the control on day 5 post-infection, but not in uninfected mice. While pulmonary viral titers were not affected by TiO2 exposure, an increase in the infiltration of lymphocytes into the alveolar septa in lung tissues was observed. Immunohistochemical analysis revealed aggregation of TiO2 nanoparticles near inflammatory cells in the severely affected region. Thus, a single exposure to TiO2 nanoparticles affected the immune system and exacerbated pneumonia in RSV-infected mice.

Particle size distribution of aerosols sprayed from household hand-pump sprays containing fluorine-based and silicone-based compounds

Japan has published safety guideline on waterproof aerosol sprays. Furthermore, the Aerosol Industry Association of Japan has adopted voluntary regulations on waterproof aerosol sprays. Aerosol particles of diameter less than 10 µm are considered as "fine particles". In order to avoid acute lung injury, this size fraction should account for less than 0.6% of the sprayed aerosol particles. In contrast, the particle size distribution of aerosols released by hand-pump sprays containing fluorine-based or silicone-based compounds have not been investigated in Japan. Thus, the present study investigated the aerosol particle size distribution of 16 household hand-pump sprays. In 4 samples, the ratio of fine particles in aerosols exceeded 0.6%. This study confirmed that several hand-pump sprays available in the Japanese market can spray fine particles. Since the hand-pump sprays use water as a solvent and their ingredients may be more hydrophilic than those of aerosol sprays, the concepts related to the safety of aerosol-sprays do not apply to the hand pump sprays. Therefore, it may be required for the hand-pump spray to develop a suitable method for evaluating the toxicity and to establish the safety guideline.

Analysis of isothiazolinone preservatives in polyvinyl alcohol cooling towels used in Japan

Recently, cases of contact dermatitis that were related to the use of polyvinyl alcohol (PVA) cooling towels containing isothiazolinone preservatives were reported in Japan. The aim of this investigation was to analyze the concentrations of five different isothiazolinone compounds present in PVA towels and to assess the effectiveness of washing in removing the preservatives from new towels prior to being used for the first time. Twenty-seven PVA towels were used in this study. Two groups (i.e., laboratory-simulation and volunteer) of washing experiments were conducted to evaluate the effect of washing procedures. Qualitative and quantitative analyses were performed by LC/MS/MS, which detected 2-methyl-4-isothiazolin-3-one (MI) and 5-chloro-2-methyl-4-isothaizolin-3-one (CMI) in 23 samples (MI: 0.29-154 μg g-wet(-1), CMI: 2.2-467 μg g-wet(-1)), 2-n-octyl-4-isothiazolin-3-one (OIT) in one sample (478 μg g-wet(-1)). The compounds 4,5-Dichloro-2-n-octyl-4-isothiazolin-3-one (2Cl-OIT) and 1,2-benzisothiazolin-3-one (BIT) were not detected in all samples. We confirmed the presence of residual MI, CMI, and OIT in the washed towels, and the residual-to-original content ratio of OIT was higher than that of MI and CMI in PVA towels, due to the higher hydrophobicity of OIT than MI and CMI. A concern has been raised about the occurrence of contact dermatitis being caused by the use of PVA towels. It is suggested that a detailed description of isothiazolinone preservatives in PVA towels and an effective washing procedure for the removal of these preservatives should be provided by the manufacturer. Further, alternative non-sensitizing preservatives might be considered for the manufacture of PVA cooling towels in the future.

A case of gastric aberrant pancreas with bleeding and diagnosed by endoscopic ultrasonography

Aberrant pancreas is used to describe ectopic pancreatic tissue lying outside its normal location with no anatomic or vascular connection to the pancreas proper. Patients with aberrant pancreas are usually asymptomatic, so aberrant pancreas are typically discovered incidentally during endoscopy, surgery, or autopsy. This time, we report a case of gastric aberrant pancreas bleeding was repeated and endoscopic hemostasis was difficult. A 22-year-old man was admitted to a hospital with a complaint of epigastric pain and melena. Upper gastrointestinal endoscopy and endoscopic ultrasonography (EUS) revealed a submucosal tumor with a bleeding ulcer at the anterior wall of the antrum in the stomach, and diagnosed it as an aberrant pancreas. It was hard to stop bleeding by in total 7 times endoscopic hemostasis and anemia was gradually progressed, so partial gastrectomy was performed. This gastric tumor measured 40 mm × 30 mm × 20 mm and had a severe ulcerative change. The pathological diagnosis was aberrant pancreas with Langerhans islet, acinous cells and excretory duct. (Heinrich type) Until December 2013 in Japan, 13 cases of gastric aberrant pancreas with bleeding have been reported and in these, a surgery was done in 11 cases. In gastric aberrant pancreas cases with ulcer formation like this case, endoscopic hemostasis is expected to be difficult, and surgery is necessary. Hence, early accurate diagnosis by EUS is a very important to decide better treatment plan.

[Examination of identification test of certain aromatic amines originating from azo colorants in textile and leather products using high performance liquid chromatography]

Azo colorants that generate primary aromatic amines (PAAs) have been recently deliberated as a controlled harmful substance by the "Act on the Control of Household Products Containing Harmful Substances" in Japan. Therefore, we examined an identification test for 22 kinds of PAAs originating from the azo colorants in commercial textile products and leather products using high performance liquid chromatography (HPLC). When a PAAs standard solution containing 2,4-xylidine and 2,6-xylidine was analyzed using the condition according to EN14362-1:2012 at 240 nm as a basic condition, we observed enough separation for all the PAAs to identify. However, in the some sample solutions, the peaks of several PAAs were overlapped with the interference peaks, and their identifications were difficult. In these cases, some PAAs were able to identify by alteration to suitable wavelength. Furthermore, the retention time of almost PAAs and interference peaks were changed by using acetonitrile as the organic solvent in eluent or phenyl type column. These modifications were helpful for identification of PAA which was overlapped to interference substances by the basic condition. Thus, we suggest the HPLC condition for an identification test is in accordance to that described in EN14362-1:2013. And we propose that the HPLC condition can be modified as necessary.

[Characterization of cases contravening of regulations regarding primary aromatic amines originating from azo dyes in commercial textile products and leather products in European Union]

Contraventions of regulations regarding primary aromatic amines (PAAs) originating from azo dyes in commercial textile products and leather products in European Union (EU), notified in the period between 2006 and 2012 were collected from the Rapid Alert System for non-food consumer products (RAPEX), were characterized. Various types of products (clothes, footwear, bedding, etc.) and their raw materials (cotton, silk, viscose, leather, etc.) were reported to have contravened the regulations. The contravention frequencies for products made in China and India were higher than those for other countries. Ten percentage of the country in which the reported products were produced was unknown. The notification frequencies for benzidine and 4-aminoazobenzene were higher than those for other PAAs. Contravention of regulations regarding benzidine, 4-aminoazobenzene, and 3,3'-dimethoxybenzidine were notified every year. Contraventions of regulations regarding five PAAs--classified as IARC group 1--were notified one or several times. Since the scale of the survey conducted in Japan were small compared with RAPEX, it is necessary that many kinds and number of products should be surveyed in Japan. In addition, it is also necessary to pay attention to 4-aminoazobenzene, while it has not been detected in the previous studies conducted in Japan.

Yokukansan inhibits morphine tolerance and physical dependence in mice: the role of α₂A-adrenoceptor

Yokukansan (YKS) is a traditional Japanese medicine consisting of seven medicinal herbs that is used for the treatment of neurosis, insomnia, and the behavioral/psychological symptoms of dementia. This study examined the effects of YKS on morphine tolerance and physical dependence in mice. Daily oral administration of YKS (0.5 or 1.0 g/kg) for 3 weeks significantly attenuated morphine tolerance and naloxone-precipitated morphine withdrawal signs (jumps and body weight loss) without affecting the analgesic effect of morphine. The inhibitory effect of YKS on withdrawal jumps in morphine-dependent mice was blocked by a single pretreatment with an α(2)-adrenoceptor antagonist, yohimbine, but not by an α(1)-adrenoceptor antagonist, prazosin. A similar inhibitory effect on withdrawal jumps was observed by repeated administration of yohimbine. The membrane expression of α(2A)-adrenoceptors in the pons/medulla was decreased in morphine withdrawn animals; this reduction was prevented by repeated administration of YKS or yohimbine. Competitive radioligand and [(35)S]guanosine-5'-O-(3-thiotriphosphate) binding assays revealed that YKS and its constituent herbs, Glycyrrhiza (GR) and Uncaria hook (UH), had specific binding affinity for and antagonist activity against the α(2A)-adrenoceptor. Certain chemical constituents, including GR -derived glycyrrhizin and its metabolite, 18β-glycyrrhetinic acid, and UH-derived geissoschizine methyl ether (GME), shared such activities. Repeated administration of GR, UH, glycyrrhizin or GME significantly inhibited morphine withdrawal signs. These results suggest that YKS and its active constituents inhibit morphine tolerance and physical dependence, and that the latter is due at least in part to the prevention of the decreased membrane expression of the α(2A)-adrenoceptor in the brainstem by its prolonged blockade.

Developmental exposure to manganese chloride induces sustained aberration of neurogenesis in the hippocampal dentate gyrus of mice

The effect of exogenously administered manganese (Mn) on developmental neurogenesis in the hippocampal dentate gyrus was examined in male mice after maternal exposure to MnCl(2) (0, 32, 160, or 800 ppm as Mn in diet) from gestational day 10 to day 21 after delivery on weaning. Immunohistochemistry was performed to monitor neurogenesis and interneuron subpopulations on postnatal days (PNDs) 21 and 77 (adult stage). Reelin-synthesizing γ-aminobutyric acid (GABA)ergic interneurons increased in the hilus with ≥ 160 ppm on weaning to sustain to PND 77 at 800 ppm. Apoptosis in the neuroblast-producing subgranular zone increased with 800 ppm and TUC4-expressing immature granule cells decreased with 800 ppm on weaning, whereas at the adult stage, immature granule cells increased. On PND 21, transcript levels increased with Reln and its receptor gene Lrp8 and decreased with Dpysl3 coding TUC4 in the dentate gyrus, confirming immunohistochemical results. Double immunohistochemistry revealed a sustained increase of reelin-expressing and NeuN-lacking or weakly positive immature interneurons and NeuN-expressing mature neurons in the hilus through to the adult stage as examined at 800 ppm. Brain Mn concentrations increased at both PNDs 21 and 77 in all MnCl(2)-exposed groups. These results suggest that Mn targets immature granule cells causing apoptosis and neuronal mismigration. Sustained increases in immature reelin-synthesizing GABAergic interneurons may represent continued aberration in neurogenesis and following migration to cause an excessive response for overproduction of immature granule cells through to the adult stage. Sustained high concentration of Mn in the brain may be responsible for these changes.

Geissoschizine methyl ether, an alkaloid in Uncaria hook, is a potent serotonin ₁A receptor agonist and candidate for amelioration of aggressiveness and sociality by yokukansan

Yokukansan (YKS), a traditional Japanese medicine, is composed of seven kinds of dried herbs. It is widely prescribed in clinical situation for treating psychiatric disorders such as aggressiveness in patients with dementia. We previously demonstrated that YKS and Uncaria hook (UH), which is a constituent herb of YKS, had a partial agonistic effect to 5-HT(1A) receptors in vitro. However, it has still been unclear whether this in vitro effect is reflected in in vivo, and what the active ingredients are. The purpose of the present study is to find the active ingredient in YKS and to demonstrate the effect in in vivo. In the present study, we first studied the effect of YKS and UH on aggressiveness and sociality in socially isolated mice. YKS and UH ameliorated the isolation-induced increased aggressiveness and decreased sociality, and these ameliorative effects were counteracted by coadministration of 5-HT(1A) receptor antagonist WAY-100635, or disappeared by eliminating UH from YKS. These results suggest that the effect of YKS is mainly attributed to UH, and the active ingredient is contained in UH. To find the candidate ingredients, we examined competitive binding assay and [(35)S] guanosine 5'-O-(3-thiotriphosphate) (GTPγS) binding assay of seven major alkaloids in UH using Chinese hamster ovary cells expressing 5-HT(1A) receptors artificially. Only geissoschizine methyl ether (GM) among seven alkaloids potently bound to 5-HT(1A) receptors and acted as a partial agonist. This in vitro result on GM was further demonstrated in the socially isolated mice. As did YKS and UH, GM ameliorated the isolation-induced increased aggressiveness and decreased sociality, and the effect was counteracted by coadministration of WAY-100635. These lines of results suggest that GM in UH is potent 5-HT(1A) receptor agonist and a candidate for pharmacological effect of YKS on aggressiveness and sociality in socially isolated mice.

In vivo delivery of interferon-α gene enhances tumor immunity and suppresses immunotolerance in reconstituted lymphopenic hosts

T cells recognize tumor-associated antigens under the condition of lymphopenia-induced homeostatic proliferation (HP); however, HP-driven antitumor responses gradually decay in association with tumor growth. Type I interferon (IFN) has important roles in regulating the innate and adaptive immune system. In this study we examined whether a tumor-specific immune response induced by IFN-α could enhance and sustain HP-induced antitumor immunity. An intratumoral IFN-α gene transfer resulted in marked tumor suppression when administered in the early period of syngeneic hematopoietic stem cell transplantation (synHSCT), and was evident even in distant tumors that were not transduced with the IFN-α vector. The intratumoral delivery of the IFN-α gene promoted the maturation of CD11c(+) cells in the tumors and effectively augmented the antigen-presentation capacity of the cells. An analysis of the cytokine profile showed that the CD11c(+) cells in the treated tumors secreted a large amount of immune-stimulatory cytokines including interleukin (IL)-6. The CD11c(+) cells rescued effector T-cell proliferation from regulatory T-cell-mediated suppression, and IL-6 may have a dominant role in this phenomenon. The intratumoral IFN-α gene transfer creates an environment strongly supporting the enhancement of antitumor immunity in reconstituted lymphopenic recipients through the induction of tumor-specific immunity and suppression of immunotolerance.

Yokukansan, a traditional Japanese medicine, ameliorates memory disturbance and abnormal social interaction with anti-aggregation effect of cerebral amyloid β proteins in amyloid precursor protein transgenic mice

The deposition of amyloid β protein (Aβ) is a consistent pathological hallmark of Alzheimer's disease (AD) brains. Therefore, inhibition of Aβ aggregation in the brain is an attractive therapeutic and preventive strategy in the development of disease-modifying drugs for AD. An in vitro study demonstrated that yokukansan (YKS), a traditional Japanese medicine, inhibited Aβ aggregation in a concentration-dependent manner. An in vivo study demonstrated that YKS and Uncaria hook (UH), a constituent of YKS, prevented the accumulation of cerebral Aβ. YKS also improved the memory disturbance and abnormal social interaction such as increased aggressive behavior and decreased social behavior in amyloid precursor protein transgenic mice. These results suggest that YKS is likely to be a potent and novel therapeutic agent to prevent and/or treat AD, and that this may be attributed to UH.

[Analysis of volcanic-ash-based insoluble ingredients of facial cleansers]

The substance termed "Shirasu balloons", produced by the heat treatment of volcanic silicates, is in the form of hollow glass microspheres. Recently, this substance has gained popularity as an ingredient of facial cleansers currently available in the market, because it lends a refreshing and smooth feeling after use. However, reports of eye injury after use of a facial cleanser containing a substance made from volcanic ashes are on the rise. We presumed that the shape and size of these volcanic-ash-based ingredients would be the cause of such injuries. Therefore, in this study, we first developed a method for extracting water-insoluble ingredients such as "Shirasu balloons" from the facial cleansers, and then, we examined their shapes and sizes. The insoluble ingredients extracted from the cleansers were mainly those derived from volcanic silicates. A part of the ingredients remained in the form of glass microspheres, but for the most part, the ingredients were present in various forms, such as fragments of broken glass. Some of the fragments were larger than 75 microm in length. Foreign objects having a certain hardness, shape, and size (e.g., size greater than 75 microm) can possibly cause eye injury. We further examined insoluble ingredients of facial scrubs, such as artificial mineral complexes, mud, charcoal, and polymers, except for volcanic-silicate-based ingredients. The amounts of insoluble ingredients extracted from these scrubs were small and did not have a sharp edge. Some scrubs had ingredients with particles larger than 75 microm in size, but their specific gravities were small and their hardness values were much lower than those of glass microspheres of ingredients such as "Shirasu balloons". Because the fragments of glass microspheres can possibly cause eye injury, the facial cleansers containing large insoluble ingredients derived from volcanic ashes should be avoided to use around eyes.

Permeation pathway of macromolecules and nanospheres through skin

The permeation pathway of macromolecules and nanospheres through skin was evaluated using fluorescent isothiocyanate (FITC)-dextran (average MW, 4 kDa) (FD-4) and nanospheres (500 nm in diameter) in hairless rat abdominal skin and porcine ear skin as well as a three-dimensional cultured human skin model (cultured skin model). A low molecular hydrophilic compound, sodium fluorescein (FL) (MW, 376 Da), was used for comparison. FL penetrated the stratum corneum and permeated the viable epidermis of hairless rat skin, whereas less permeation of FL was observed through the cultured skin model, suggesting that the primary permeation pathway for the hydrophilic material may be skin appendages through the rat skin. A macromolecular compound, FD-4, was distributed through the hair follicles of the rat skin. In addition, nanospheres were detected in the hair follicles of porcine skin, although no skin permeation was detected. These findings suggest that appendage routes such as hair follicles can be a penetration pathway of macromolecules and nanospheres through skin.

[Analysis of preservatives used in cosmetic products: salicylic acid, sodium benzoate, sodium dehydroacetate, potassium sorbate, phenoxyethanol, and parabens]

Preservatives are used to inhibit the growth of microorganisms in cosmetic products. The Japanese standards for cosmetics set restrictions on the maximum amount of each preservative added to cosmetics as per the purpose of use of cosmetics. For the investigation into the actual conditions of commonly used preservatives in commercial cosmetics, we analyzed parabens, phenoxyethanol, sodium benzoate, sodium dehydroacetate, salicylic acid, and potassium sorbate by high-performance liquid chromatography (HPLC). Twenty-one samples were obtained from cosmetic product manufacturers located in 14 prefectures in Japan. Among different acid- and salt-based preservatives, sodium benzoate was observed to have been used in many products. These acid- and salt-based preservatives were used with parabens in personal washing products, such as shampoo and soap. The labels of two of the cosmetic product samples displayed inaccurate ingredient information, that is, a preservative other than the one used in the corresponding product was listed on them. The amount of preservatives used did not exceed regulatory limits in any of the analyzed samples.