Radiation occupational health interventions offered to radiation workers in response to the complex catastrophic disaster at the Fukushima Daiichi Nuclear Power Plant

The Fukushima Daiichi Nuclear Power Plant (NPP) 1 was severely damaged from the chain reaction of the Great East Japan Earthquake and Tsunami on 11 March 2011, and the consequent meltdown and hydrogen gas explosions. This resulted in the worst nuclear accident since the Chernobyl accident of 1986. Just as in the case of Chernobyl, emergency workers were recruited to conduct a wide range of tasks, including disaster response, rescuing activities, NPP containment, and radiation decontamination. This paper describes the types and efficacy of the various occupational health interventions introduced to the Fukushima NPP radiation workers. Such interventions were implemented in order to prevent unnecessary radiation overexposure and associated adverse health effects and work injuries. Less than 1% of all emergency workers were exposed to external radiation of >100 mSv, and to date no deaths or health adversities from radiation have been reported for those workers. Several occupational health interventions were conducted, including setting of new regulatory exposure limits, improving workers' radiation dosimetry, administration of stable iodine, running an occupational health tracking system, and improving occupational medicine and preventative care. Those interventions were not only vital for preventing unnecessary radiation, but also for managing other general health issues such as mental health, heat illness and infectious diseases. Long-term administration of the aforementioned occupational health interventions is essential to ensure the ongoing support and care for these workers, who were put under one of the most severe occupational health risk conditions ever encountered.

The effects of radio-frequency electromagnetic fields on T cell function during development

With the widespread use of radio-frequency devices, it is increasingly important to understand the biological effects of the associated electromagnetic fields. Thus, we investigated the effects of radio-frequency electromagnetic fields (RF-EMF) on T cell responses during development due to the lack of science-based evidence for RF-EMF effects on developmental immune systems. Sprague Dawley (SD) rats were exposed to 2.14-GHz wideband code division multiple-access (W-CDMA) RF signals at a whole-body specific absorption rate (SAR) of 0.2 W/kg. Exposures were performed for a total of 9 weeks spanning in utero development, lactation and the juvenile period. Rats were continuously exposed to RF-EMF for 20 h/day, 7 days/week. Comparisons of control and exposed rats using flow cytometry revealed no changes in the numbers of CD4/CD8 T cells, activated T cells or regulatory T cells among peripheral blood cells, splenocytes and thymocytes. Expression levels of 16 genes that regulate the immunological Th1/Th2 paradigm were analyzed using real-time PCR in the spleen and thymus tissues of control and RF-EMF-exposed rats. Although only the Il5 gene was significantly regulated in spleen tissues, Il4, Il5 and Il23a genes were significantly upregulated in thymus tissues following exposure to RF-EMF. However, ELISAs showed no changes in serum IL-4 protein concentrations. These data indicate no adverse effects of long-term RF-EMF exposure on immune-like T cell populations, T cell activation, or Th1/Th2 balance in developing rats, although significant transcriptional effects were observed.

Gaseous chemical compounds in indoor and outdoor air of 602 houses throughout Japan in winter and summer

A nationwide survey of indoor air quality in Japan was conducted using four types of diffusive samplers. Gaseous chemical compounds such as carbonyls, volatile organic compounds (VOC), acid gases, basic gases, and ozone were measured in indoor and outdoor air of 602 houses throughout Japan in winter and summer. Four kinds of diffusive samplers were used in this study: DSD-BPE/DNPH packed with 2,4-dinitrophenyl hydrazine and trans-1,2-bis(2-pyridyl)ethylene coated silica for ozone and carbonyls; VOC-SD packed with Carboxen 564 particles for volatile organic compounds; DSD-TEA packed with triethanolamine impregnated silica for acid gases; and DSD-NH3 packed with phosphoric acid impregnated silica for basic gases. These samplers are small and lightweight and do not require a power source, hence, it was possible to obtain a large number of air samples via mail from throughout Japan. Almost all compounds in indoor air were present at higher levels in summer than in winter. In particular, formaldehyde, toluene, and ammonia were strongly dependent on temperature, and their levels increased with temperature. The nitrogen dioxide concentration in indoor air particularly increased only during winter and was well correlated with the formic acid concentration (correlation coefficient=0.959). Ozone concentrations in indoor air were extremely low compared with the outdoor concentrations. Ozone flowing from outdoor air may be decomposed quickly by chemical compounds in indoor air; therefore, it is suggested that the indoor/outdoor ratio of ozone represents the ventilation of the indoor environment.

[The need for tobacco control in Japan based on Articles 9 and 10 of the World Health Organization Framework Convention on Tobacco Control (WHO FCTC), regulation of the contents of tobacco products, and regulation of tobacco product disclosures]

In Japan, ultralow-nicotine cigarette brands with ventilation holes on the cigarette filters have been widely marketed to smokers. The use of these cigarette brands leads to compensation smoking. Menthol cigarette brands that have a cooling and numbing effect are also sold. In 2013, smokeless tobacco products similar to the Swedish snus, which is banned for sale in the European Union except in Sweden, were released in Japanese markets. These tobacco products have "toxicity," have a "ventilation filter," are "attractive," and promote "dependence." Tobacco smoke and smokeless tobacco are classified into "Group 1: Carcinogenic to humans" by the International Agency for Research on Cancer (IARC). The purpose of Articles 9 and 10 of the World Health Organization Framework Convention on Tobacco Control (WHO FCTC) is to regulate the contents of tobacco products as well as to regulate tobacco product disclosures. The implementation of some other articles has gradually advanced in Japan. However, that of Articles 9 and 10 is late. Japanese governmental authorities are being urged to immediately implement Articles 9 and 10.

[WHO Framework Convention on Tobacco Control (FCTC) Article 11: packaging and labelling of tobacco products]

The World Health Organization (WHO) Framework Convention on Tobacco Control (FCTC) requires member countries to implement measures aimed at reducing the demand for tobacco products. FCTC article 11 describes the important forms of health communication and packaging regulations. And this article recommends on large pictorial health warnings and encourages more effective forms of disclosure on constituents and emissions. Furthermore, article 11 recognizes the importance of the package as a promotional vehicle for tobacco companies and requires the removal of potentially misleading packaging information, including the terms "light" and "mild." The Conference of the Parties (COP) adopted guidelines for implementation of article 11 on "Packaging and labelling of Tobacco Products". Some countries, such as Canada, the U.S.A., Australia, EU countries etc. positively promoted tobacco control by implementing countermeasures such as the graphic health warning labels and plain packages. These countermeasures showed the significant effects of decreasing smoking rate and preventing smoking initiation in young people. Furthermore, these warning labels were effective for the literally challenged. However, the Japanese government has not implemented these countermeasures, and only limited texts are shown on Japanese tobacco packaging. Therefore, Japan should emulate approaches taken by other countries, and promote the tobacco control policy in accordance with FCTC.

[Measurement of Chemical Compounds in Indoor and Outdoor Air in Chiba City Using Diffusive Sampling Devices]

OBJECTIVES

Indoor air quality (IAQ) is a major concern, because people on average spend the vast majority of their time indoors and they are repeatedly exposed to indoor air pollutants. In this study, to assess indoor air quality in Chiba City, gaseous chemical compounds were surveyed using four types of diffusive sampler.

METHODS

Gaseous chemical compounds such as carbonyls, volatile organic compounds (VOC), acid gases, basic gases, and ozone were measured in indoor and outdoor air of 50 houses throughout Chiba City in winter and summer. Four types of diffusive sampler were used in this study: DSD-BPE/DNPH packed with 2,4-dinitrophenyl hydrazine and trans-1,2-bis(2-pyridyl)ethylene-coated silica for ozone and carbonyls; VOC-SD packed with Carboxen 564 particles for volatile organic compounds; DSD-TEA packed with triethanolamine-impregnated silica for acid gases; and DSD-NH3 packed with phosphoric acid-impregnated silica for basic gases.

RESULTS

Almost all compounds in indoor air were detected at higher concentrations in summer than in winter. However, the nitrogen dioxide concentration in indoor air particularly increased only in winter, which well correlated with the formic acid concentration (correlation coefficient=0.974). The compound with the highest concentrations in indoor air was p-dichlorobenzene, with recorded levels of 13,000 μg m(-3) in summer and 1,100 μg m(-3) in winter in indoor air.

CONCLUSIONS

p-Dichlorobenzene in summer and nitrogen dioxide in winter are detected at markedly high concentrations. Pollution control and continuous monitoring of IAQ are indispensable for human health.

Prevalence and Characteristics of Chemical Intolerance: A Japanese Population-Based Study

Population-based cross-sectional study was performed to estimate the prevalence of chemical intolerance and to examine the characteristics of the sample. A Web-based survey was conducted that included 7,245 adults in Japan. The criteria for chemical intolerance proposed by Skovbjerg yielded a prevalence of 7.5% that was approximately consistent with that reported from a Danish population-based survey. Female gender, older age, and renovation in the house during the past 7 years were positively associated with chemical intolerance. Improvements in the condition were observed with daily ventilation habits. Medical history of atopic dermatitis, allergic rhinitis, food allergy, multiple chemical sensitivity, and depression were associated with chemical intolerance. Fatigue, depressed mood, and somatic symptoms were also positively correlated with chemical intolerance. Better elucidation of the causes, comorbidities, concomitants, and consequences of chemical intolerance has the potential to provide effective solutions for its prevention and treatment.

DNA damage signaling guards against perturbation of cyclin D1 expression triggered by low-dose long-term fractionated radiation

Cyclin D1 expression is precisely controlled during cell-cycle progression. However, repeated exposure to low-dose fractionated radiation (FR) abrogates cell cycle-dependent cyclin D1 degradation by constitutive activation of AKT survival signaling in normal human fibroblasts. The resulting abnormal nuclear cyclin D1 accumulation induces defects in DNA replication and resulting DNA double-strand breaks, and is associated with induction of genomic instability in low-dose irradiated cells. Here, we investigated the role of DNA damage signaling against such perturbed cell-cycle control of cyclin D1 expression. Nuclear cyclin D1 accumulation was induced within 7 days after low-dose FR (0.01 Gy or 0.05 Gy per fraction) in ATM-deficient cells (AT5BIVA), but appeared later in AT5BIVA cells harboring human ATM cDNA. Thus, ATM prevents abnormal nuclear cyclin D1 accumulation at early time points after low-dose FR. We further demonstrated that ATM-mediated downregulation of protein phosphatase 2A activity caused activation of the AKT/cyclin D1 pathway after long-term FR. Perturbation of cyclin D1 expression induced Rad51 foci that indicate homologous recombination repair (HRR) in control cells, while ATM- and NBS1-deficient cells (GM7166) failed to induce Rad51 foci after long-term low-dose FR. After 21 days of FR, NBS1- and ATM-deficient cells showed a decrease in nuclear cyclin D1-positive cells, and an increase in apoptotic cells. Similarly, inhibition of ATM with KU55933 abrogated nuclear cyclin D1 accumulation by induction of apoptosis in ATM-complemented cells exposed to low-dose FR. In conclusion, we here demonstrate that ATM is involved in controlling cyclin D1 levels after low-dose FR. DNA damage signaling mitigates the harmful effects of low-dose long-term FR by suppression of cell death induced by perturbation of cyclin D1 expression.

Prevalence of diabetes and pre-diabetes among workers: Japan Epidemiology Collaboration on Occupational Health Study

AIMS

Few studies have examined the prevalence of diabetes using glycated hemoglobin (HbA1c), a newly recommended diagnostic test. We examined the prevalence of diabetes and pre-diabetes using both HbA1c and fasting plasma glucose (FPG) and their associations with risk factors for type 2 diabetes in a large-scale Japanese working population.

METHODS

Participants were 47,172 men and 8280 women aged 20-69 years who received periodic health checkup in nine companies which participated in the Japan Epidemiology Collaboration on Occupational Health study. Participants were categorized into diabetes (HbA1c≥6.5% (≥48mmol/mol), FPG≥126mg/dl (≥7.0mmol/L), or medication for diabetes), pre-diabetes (HbA1c 6.0-6.4% (42-46mmol/mol) or FPG 110-125mg/dl (6.1-6.9mmol/L) among those without diabetes), and normal glucose regulation.

RESULTS

The prevalence of diabetes was 8.0% and 3.3% in men and women, respectively. Of individuals with diabetes, approximately 80% were defined by HbA1c≥6.5% (≥48mmol/mol) criterion. The prevalence of pre-diabetes was 14.1% in men and 9.2% in women. Prevalence of these glucose abnormalities increased with advancing age, especially during mid-40s and 50s. Higher body mass index and waist circumference, hypertension, dyslipidemia, and current smoking were each associated with higher prevalence of diabetes in both men and women.

CONCLUSIONS

Using HbA1c and FPG criteria or current medication, one in 13 men and one in 30 women had diabetes in the present Japanese working population. Interventions targeted for those in an early stage of impaired glucose metabolism would be required to prevent diabetes.

Determination of carbonyl compounds generated from the E-cigarette using coupled silica cartridges impregnated with hydroquinone and 2,4-dinitrophenylhydrazine, followed by high-performance liquid chromatography

Carbonyl compounds in E-cigarette smoke mist were measured using coupled silica cartridges impregnated with hydroquinone and 2,4-dinitrophenylhydrazine, followed by high-performance liquid chromatography. A total of 363 E-cigarettes (13 brands) were examined. Four of the 13 E-cigarette brands did not generate any carbonyl compounds, while the other nine E-cigarette brands generated various carbonyl compounds. However, the carbonyl concentrations of the E-cigarette products did not show typical distributions, and the mean values were largely different from the median values. It was elucidated that E-cigarettes incidentally generate high concentrations of carbonyl compounds.

Nuclear accumulation of cyclin D1 following long-term fractionated exposures to low-dose ionizing radiation in normal human diploid cells

Cyclin D1 is a mitogenic sensor that responds to growth signals from the extracellular environment and regulates the G 1-to-S cell cycle transition. When cells are acutely irradiated with a single dose of 10 Gy, cyclin D1 is degraded, causing cell cycle arrest at the G 1/S checkpoint. In contrast, cyclin D1 accumulates in human tumor cells that are exposed to long-term fractionated radiation (0.5 Gy/fraction of X-rays). In this study we investigated the effect of fractionated low-dose radiation exposure on cyclin D1 localization in 3 strains of normal human fibroblasts. To specifically examine the nuclear accumulation of cyclin D1, cells were treated with a hypotonic buffer containing detergent to remove cytoplasmic cyclin D1. Proliferating cell nuclear antigen (PCNA) immunofluorescence was used to identify cells in S phase. With this approach, we observed S-phase nuclear retention of cyclin D1 following low-dose fractionated exposures, and found that cyclin D1 nuclear retention increased with exposure time. Cells that retained nuclear cyclin D1 were more likely to have micronuclei than non-retaining cells, indicating that the accumulation of nuclear cyclin D1 was associated with genomic instability. Moreover, inhibition of the v-akt murine thymoma viral oncogene homolog (AKT) pathway facilitated cyclin D1 degradation and eliminated cyclin D1 nuclear retention in cells exposed to fractionated radiation. Thus, cyclin D1 may represent a useful marker for monitoring long-term effects associated with exposure to low levels of radiation.

Determination of amounts of tar, nicotine, carbon monoxide, and tobacco-specific nitrosamines in the fillers of and mainstream smoke from privately imported cigarettes

OBJECTIVE

The tobacco tax in Japan was increased in October, 2010. Subsequently, the quantity of sales of domestic cigarette products decreased temporarily. However, smokers could import cigarettes directly through the internet. Because of the high value of the yen and the low price of foreign cigarettes, an individual could import cigarettes easily; however, the contents and emissions from privately imported cigarettes have not been investigated yet. In this study, we carried out a comparative analysis of domestic and privately imported cigarettes.

METHODS

Privately imported cigarettes from five brands and domestic cigarettes from the brand "Mild Seven" were selected for the study. For the fillers of the cigarettes, the levels of nicotine and tobacco-specific nitrosamines (TSNAs) were determined by methods that are usually used for cigarette products. For the mainstream smoke, the levels of tar, nicotine, carbon monoxide, and TSNAs were also determined by the methods used for cigarettes.

RESULTS

The average nicotine and TSNA levels in the fillers of the domestic cigarettes were 15.1 ± 0.19 mg/g and 1,920 ± 85.1 ng/g, respectively. The amounts of nicotine and tar in the mainstream smoke from the privately imported cigarettes were lower than those from the domestic cigarettes. However, the levels of TSNAs in the mainstream smoke from the privately imported cigarettes were higher than those from the domestic cigarettes.

CONCLUSIONS

The amounts of TSNAs in the fillers of and mainstream smoke from the privately imported cigarettes were higher than those from the domestic cigarettes. Japanese smokers should be careful about consuming privately imported cigarettes because there is a variation in the amount of hazardous constituents in these cigarettes, even when they are from the same brand.

[Measurement of hazardous chemical constituents and mutagenic activity in fillers and mainstream smoke from Neo Cedar]

OBJECTIVE

To determine constituents of fillers and mainstream smoke from Neo Cedar.

METHODS

Neo Cedar is a second-class over-the-counter (OTC) drug and similar to cigarettes in a number of ways. In particular, the design and usage are very similar to those of cigarettes. For the fillers of the drug, the levels of nicotine, tobacco-specific nitrosamines (TSNA), and heavy metals, and mutagenicity were determined using the methods for cigarette products. For the mainstream smoke, the levels of tar, nicotine, carbon monoxide (CO), TSNA, polycyclic aromatic hydrocarbons (PAH), and carbonyl compounds were also determined using the methods for cigarettes. The mainstream smoke from the drug were collected with a smoking machine using two smoking protocols (ISO and Health Canada Intense methods).

RESULTS

The nicotine and total TSNA levels in the fillers of the drug averaged 2.86 mg/g and 185 ng/g, respectively. The nine species of heavy metals were also detected in the fillers of the drug. The levels of nicotine, tar, CO, TSNA, PAH, and carbonyl compounds of mainstream smoke from the drug were higher when determined using the HCI regime than when using the ISO regime. The mutagenicity of the mainstream smoke determined using the HCI regime was also higher than that determined using the ISO regime.

CONCLUSION

In this study, all constituents of Neo Cedar were determined by methods for cigarette products. The drug had a ventilation hole on its filter. Thus, its constituents are different from those determined by the smoking protocols. Neo Cedar users should be careful of higher exposure to the hazardous gases owing to smoking patterns.

Simultaneous determination of volatile organic compounds and carbonyls in mainstream cigarette smoke using a sorbent cartridge followed by two-step elution

We developed a simple method for the simultaneous determination of volatile organic compounds (VOCs) and carbonyls in the mainstream cigarette smoke using a sorbent cartridge at ambient temperature without the traditional cryogenic impinger. A sorbent cartridge is installed between intake filter and the pump of the smoking machine. Collection of cigarette mainstream smoke is performed according to the Canadian Intense regime or the ISO regime. As adsorbent, Carboxen 572 (CX-572) is the most suitable for collection of VOCs and carbonyls in the mainstream cigarette smoke. Elution of VOCs and carbonyls from CX-572 is performed by the two-step elution with carbon disulfide and methanol. VOCs are eluted by first elution with carbon disulfide and carbonyls are eluted by second elution with methanol. For VOCs, a portion of eluate is analyzed by gas chromatography-mass spectrometry. For carbonyls, a portion of eluate is derivatized with enriched 2,4-dinitrophenylhydrazine solution and analyzed by high-performance liquid chromatography. Measurement values by CX-572 cartridge method are very close to those obtained by traditional impinger method except for 2-butanone. Impinger methods use 2,4-dinitrophenylhydrazine solution containing 50% water and 2-butanone-DNPhydrazone may be hydrolyzed with water. In the CX-572 method, the hydrolysis of 2-butanone is prevented because the eluate solution contains no water. CX-572 method can measure cigarette smoke resulting from not only one whole cigarette but also from one puff volume because of its high sensitivity and simple operation.

Can intermediate-frequency magnetic fields affect memory function-related gene expressions in hippocampus of C57BL/6J mice?

Recently, a cooking appliance based on the principle of electromagnetic induction has come to be used domestically on a widespread basis; this induction heating cooking hob mainly generates intermediate-frequency magnetic fields (IF-MF). However, whether electromagnetic fields originating from household appliances represent a health risk remains uncertain. We investigated the effect of IF-MF on the expressions of memory function-related genes and related transduction molecules in the mouse hippocampus. Male and female C57BL/6J mice were allotted to a control (sham-exposed), an exposure, or a recovery (one week after exposure) group and were exposed to IF-MF (21 kHz, 3.8 mT) one hour per day for 2 weeks. Twenty-four hour after final exposure, the expression levels of memory function-related genes and the mRNA levels for signal transduction pathway molecules in the hippocampi were examined using real-time RT-PCR. The relative mRNA expression levels of the N-methyl-D aspartate (NMDA) receptor subunits NR1, NR2A, and NR2B as well as transcription factors (calcium/calmodulin-dependent protein kinase (CaMK) -IV, cyclic AMP responsive element binding protein (CREB) -1) and neurotrophins (nerve growth factor (NGF), and brain-derived neurotrophic factors (BDNF)) were not significantly altered in the IF-MF-exposed mice. We also examined the morphology of the hippocampus using a histological analysis, but no changes in the IF-MF-exposed mice were seen. This is the first in vivo study to show that IF-MF exposure did not affect the expression levels of memory function-related genes in the hippocampus of C57BL/6J mice. The present findings suggest that IF-MF exposure may not affect cognitive function in the present animal model.

The role of cyclin D1 in response to long-term exposure to ionizing radiation

The health-related hazards resulting from long-term exposure to radiation remain unknown. Thus, an appropriate molecular marker is needed to clarify these effects. Cyclin D1 regulates the cell cycle transition from the G 1 phase to the S phase. Cyclin D1 is degraded as a G1/S checkpoint after 10 Gy of single acute radiation exposure, whereas conversely, cyclin D1 is stabilized when human tumor cells are exposed to fractionated radiation (FR) with 0.5 Gy of x-rays for 31 d. In this article, we review new findings regarding cyclin D1 overexpression in response to long-term exposure to FR. Cyclin D1 overexpression is associated with induction of genomic instability in irradiated cells. Therefore, repression of cyclin D1 expression is likely to cancel the harmful effects of long-term exposure to FR. Thus cyclin D1 may be a marker of long-term exposure to radiation and is a putative molecular radioprotection target for radiation safety.

Radioactive cesium (¹³⁴Cs and ¹³⁷Cs) content in human placenta after the Fukushima nuclear power plant accident

AIM

The degree of contamination with radioactive cesium (¹³⁴Cs and ¹³⁷Cs) in the human placenta after the accident at Fukushima nuclear power plant (FNP), which occurred on 11 March 2011, has not been assessed.

MATERIAL AND METHODS

¹³⁴Cs and ¹³⁷Cs contents were determined in 10 placentas from 10 women who gave birth to term singleton infants during the period between October 2011 and August 2012 using high-purity germanium detectors for gamma ray spectrometry. Five women resided within 50 km of FNP (neighbor group) and gave birth by the end of February 2012, while the other five women resided within 210-290 km of FNP (distant group) and gave birth in July and August 2012.

RESULTS

All except one of the 10 placentas contained detectable levels of ¹³⁴Cs and ¹³⁷Cs, ranging 0.042-0.742 Bq/kg for ¹³⁴Cs and 0.078-0.922 Bq/kg for ¹³⁷Cs. One placenta from a woman living in Tokyo contained 0.109 Bq/kg ¹³⁷Cs and no detectable level of ¹³⁴Cs (<0.054 Bq/kg). ¹³⁷Cs content was more than 0.2 Bq/kg in four and one placentas in the neighbor and distant groups, respectively.

CONCLUSION

Degree of contamination of the placenta with radioactive Cs was lower even in women who resided within 50 km of FNP compared to Japanese and Canadian placentas in the mid-1960s after repeated nuclear tests and in northern Italian placentas from 1986-1987 after the Chernobyl power plant accident.

[Determination of nicotine, tobacco-specific nitrosamine and mutagenic activity of whole tobacco in Japanese cigarettes]

OBJECTIVE

To measure the nicotine and tobacco-specific nitrosamine (TSNA) contents in whole tobacco from a variety of Japanese domestic cigarette brands and to determine mutagencity.

METHODS

The test cigarettes were the top ten best selling cigarette brands in Japan in 2006. The nicotine content in whole tobacco was measured by a modified version of the CORESTA Recommended method. The level of TSNA was measured by a modified version of the Health Canada method. Mutagenicity was assessed using the Salmonella typhimurium strains TA100, TA98 and YG1024 with the metabolic activation system (S9mix) by preincubation assays.

RESULTS

The nicotine content in the test cigarettes averaged 15.7±1.2 mg/g, and was in the range between 13.7 and 17.2 mg/g. The level of TSNA averaged 1,750 ng/g, and was in the range between 931 and 2,490 ng/g. Mutagenicity was pseudopositive in several samples of the YG1024 tester strain with and without S9mix.

CONCLUSION

The cigarettes brands were categorized into four groups (Ultra-low, Low, Medium, and High) based on the nominal nicotine yield figures printed on the cigarette packets. The nicotine content in whole tobacco of the High group was the highest. However, the level of TSNA of the high group was the lowest. The analyses of hazardous chemical compounds in whole tobacco can contribute to the reduction and regulation of the toxicity of tobacco products.

The in vivo Pig-a gene mutation assay is useful for evaluating the genotoxicity of ionizing radiation in mice

The in vivo Pig-a mutation assay has been adapted for measuring mutation in rats, mice, monkeys, and humans. To date, the assay has been used mainly to assess the mutagenicity of chemicals that are known to be powerful point mutagens. The assay has not been used to measure the biological effects associated with ionizing radiation. In this study, we modified the Pig-a gene mutation assay (Kimoto et al. [2011b]: Mutat Res 723:36-42) and used 3-color staining with fluorescently labeled anti-CD24, anti-TER-119, and anti-CD71 to detect the Pig-a mutant frequencies in total red blood cells (RBCs) and in reticulocytes (RETs) from X-irradiated mice. Single exposures to X-irradiation resulted in dose- and time-dependent increases in Pig-a mutant frequencies, and these subsequently declined over time returning to background frequencies. The same total amount of radiation, delivered either as a single dose or as four repeat doses at weekly intervals, increased Pig-a mutant frequencies to comparable levels, reaching maxima 2-3 weeks after the single dose or 2-3 weeks after the last of the repeat doses. These increased frequencies subsequently returned to background levels. Our results indicated that the 3-color Pig-a assay was useful for evaluating the in vivo genotoxicity of radiation.

Reductive amination of glutaraldehyde 2,4-dinitrophenylhydrazone using 2-picoline borane and high-performance liquid chromatographic analysis

A typical method for the measurement of glutaraldehyde (GLA) employs 2,4-dinitrophenylhydrazine (DNPH) to form GLA-DNPhydrazone derivatives. However, this method is subject to analytical errors because GLA-DNPhydrazone is a quaternary bis-derivative and forms three geometric isomers (E-E, E-Z and Z-Z) as a result of the two C[double bond, length as m-dash]N double bonds. To overcome this issue, a method for transforming the C[double bond, length as m-dash]N double bond into a C-N single bond, using reductive amination of DNPhydrazone derivatives, has been applied. The amination reaction of GLA-DNPhydrazones with 2-picoline borane is accelerated with catalytic amounts of acid and is completed within 10 minutes in the presence of 100 mmol L(-1) phosphoric acid. Reduction of GLA-DNPhydrazone by 2-picoline borane is unique and results in the formation of N-(2,4-dinitrophenyl)-1-piperidinamine (DNPPA). NMR and LC-APCI-MS data confirmed the product identification. DNPPA is very stable and did not change when stored for at least four weeks at room temperature. DNPPA has excellent solubility of 14.6 g L(-1) at 20 °C in acetonitrile. The absorption maximum wavelength and the molar absorptivity of DNPPA were 351 nm and 4.2 × 10(4) L mol(-1) cm(-1) respectively. Complete separation between the reduced forms of C1-C10 aldehyde DNPhydrazones, including DNPPA, can be achieved by operating the reversed-phase high-performance liquid chromatograph at 351 nm in gradient mode using a C18 amide column. The reductive amination method for GLA overcomes analytical errors caused by E-E, E-Z and Z-Z geometrical isomers.

[Determination of tobacco-specific N'-nitrosamines in mainstream smoke from Japanese cigarettes]

OBJECTIVES

Mainstream smoke from cigarettes contains tobacco-specific N'-nitrosamines (TSNAs) listed as Group 1 and 3 carcinogens by the International Agency for Research on Cancer (IARC). Herein, we report on a method of measuring the concentrations of TSNAs in mainstream smoke from the ten top-selling Japanese cigarette brands using an ISO regime by International Organization for Standardization (ISO) and HCI regime of Health Canada.

METHODS

Tar in mainstream smoke was collected on a Cambridge filter pad using a smoking machine. The filter pad was immersed in 40 mL of ammonium acetate (pH 6.8) and shaken for 30 min. The extract was then loaded into a C18 column. After washing with 5 mL of 10% methanol and eluting with 5 mL of 70% methanol, the eluate was concentrated to 1 mL for LC-MS/MS analysis.

RESULTS

The concentrations of TSNAs in all cigarette brands were higher when determined using the HCI regime than when determined using the ISO regime. Furthermore, the concentrations of TSNAs measured using both the ISO and HCI regimes showed negligible correlation to the tar and nicotine concentrations indicated on package labels. The cigarette samples used in the study were categorized into four classes: ultralow-, low-, medium-, and high-yield brands, which corresponded to 1, 3-6, 8-10, and 14 mg tar/cigarette, respectively. The concentration of TSNAs in ultralow-yield cigarettes was 210 ng/cigarette, as measured using the HCI regime, which was nearly equal to that in high-yield cigarettes (180 ng/cigarette).

CONCLUSIONS

Exposure to TSNAs from mainstream smoke from ultralow-yield cigarettes is comparable to that from high-yield cigarettes. To properly evaluate the risk of smoking, not only the concentrations of tar and nicotine but also those of other chemicals, including TSNAs, should be printed on package labels.

Effect of the Fukushima nuclear power plant accident on radioiodine (¹³¹ I) content in human breast milk

BACKGROUND

Environmental pollution with radioiodine (iodine-131, (131) I) occurred after an accident at the Fukushima nuclear power plant (FNP) on March 11, 2011, in Japan. Whether environmental pollution with (131) I can contaminate human breast milk has not been documented.

METHODS

The (131) I content was determined in 126 breast milk samples from 119 volunteer lactating women residing within 250 km of the FNP, between April 24 and May 31, 2011. The degree of environmental pollution was determined based on the data released by the Japanese government.

RESULTS

An (131) I content of 210 Bq/kg in the tap water in Tokyo, which is located 230 km south of the FNP, on March 22 and of 3500 Bq/kg in spinach sampled in a city located 140 km southwest of the FNP on March 19 decreased over time to <21 Bq/kg on March 27 and 12 Bq/kg on April 26, respectively. Seven of the 23 women who were tested in April secreted a detectable level of (131) I in their breast milk. The concentrations of (131) I in the breast milk of the seven women were 2.3 Bq/kg (on April 24), and 2.2, 2.3, 2.3, 3.0, 3.5 and 8.0 (on April 25); the concentrations of (131) I in the tap water available for these seven women at the same time were estimated to be <1.3 Bq/kg. None of the remaining 96 women tested in May exhibited a detectable concentration of (131) I in their breast milk samples.

CONCLUSIONS

The contamination of breast milk with (131) I can occur even when only mild environmental (131) I pollution is present.