Tiered human health risk assessment of antibacterial quaternary ammonium compounds (QACs) in dishwashing detergents.

Quaternary ammonium compounds (QACs) are widely used in consumer products because of their unique antibacterial properties, and dishwashing detergents are a major source of exposure through oral, inhalation, and dermal routes. The three classes of QACs, including benzalkonium chloride (BAC), n-alkyldimethylethylbenzylammonium chloride (ADEBAC), and di-n-alkyldimethylammonium chloride (DDAC), in spray and non-spray types of dishwashing detergents were quantified by high-performance liquid chromatography-mass spectrometry. A tiered risk assessment approach was also considered. In the Tier 1 assessment, the mean and worst-case exposure were estimated to screen for rough exposure and risk levels. In the Tier 2 assessment, mean and upper-tail exposure levels were calculated based on the exposure parameters of Korean consumers using Monte Carlo simulation. QACs had a low frequency of detection of up to 20% in dishwashing detergents, and the contents of detected QACs varied depending on the individual samples. Based on the results of the Tier 1 assessment, BACs and DDACs posed potential health risks via inhalation and dermal routes. Tier 2 assessment suggested that the current level of oral and dermal exposure of Korean consumers to QACs in dishwashing detergents is unlikely to pose a health risk, even for upper-tail exposure groups. However, the present results suggest that spray-type DDACs may pose a health risk in the upper-tail inhalation exposure group, and further investigation is required to clarify this risk.

Survey of characteristics of exposure to mainstream cigarette smoke using discarded cigarette butts from Korean smokers.

Evaluating the characteristics of exposure to mainstream cigarette smoke is an essential field in tobacco research because of the large risk burden among smokers. Detailed evaluation of the complex factors pertaining to the exposure of smokers to mainstream cigarette smoke was attempted by analysis of discarded cigarette butts. A total of 5475 samples of discarded cigarette butts was collected to investigate the exposure characteristics in relation to Korean smokers. The basic physico-chemical characteristics of cigarettes, including the filter length, filter type, menthol addition, and nicotine and tar content, were determined and the manufacturer and cigarette size were identified. The tobacco-burned percentage (TBP)) and tar staining were used as physical markers, and actual human exposure to cigarette smoke was determined using the part filter method. Multiple linear regression analyses and generalized ordinal logistic regression analysis were conducted to identify the relationship between the socio-demographic factors and the physico-chemical characteristics of the cigarettes themselves and the exposure characteristics. Significant associations were observed between the TBP and age group, occupational group, manufacturer, tar staining, ISO tar content, and filter length. Increased odds of smoking with a heavier tar stain among Korean smokers were associated with blue collar workers vs. other workers, manufacturer B vs. other manufacturers, recess filter vs. other filter types, ISO tar content, and TBP. Finally, significant associations between the log-transformed human-smoked tar and nicotine yields and occupational group, the TBP, tar staining, and physico-chemical properties of cigarettes were found and were used to propose models for predicting the actual exposure to tar and nicotine. The proposed models account for 60-61% and 47-49% of the variance of human exposure to tar and nicotine, respectively. This analysis of discarded cigarette butts revealed that various factors, including socio-demographic factors such as age group and occupational group, as well as the physico-chemical properties of cigarette products such as the filter type and length, cigarette size, ISO tar and nicotine content, and mentholation, affect the characteristics of exposure of Korean smokers to mainstream cigarette smoke.

Risk assessment of toxicants on WHO TobReg priority list in mainstream cigarette smoke using human-smoked yields of Korean smokers.

Recently, the World Health Organization Study Group on Tobacco Product Regulation (WHO TobReg) announced a priority list of 38 toxicants among the more than 7000 chemicals found in cigarette smoke, building upon previous lists of toxicants in cigarette smoke. Here, we conducted a comprehensive study on the quantitative exposure and risk characterization of these priority toxicants in mainstream cigarette smoke listed by the WHO TobReg. The human-smoked toxicant yields estimated from spent cigarette butts of a total of 361 smokers using the part-filter method (PFM) were applied to current exposure and risk estimation for the first time. The PFM can estimate human-smoked yields of toxicants using smokers' maximum mouth-level exposure. The human-smoked yield of each toxicant was converted to systemic uptake by considering bioavailability. Risk indicators-including the incremental lifetime cancer risk (ILCR), cumulative ILCR, hazard quotient (HQ), hazard indices (HIs), and margin of exposure (MOE)-were estimated from the systemic uptake of toxicants combined with Korean exposure factors by gender and age group as well as for total smokers. It was demonstrated that cigarette smoking results in significant cancer and non-cancer health risks. A sensitivity analysis showed that the human-smoked toxicant yield is one of the most important contributors to risk level variations. Our risk estimation suggested that previous risk assessments might have ignored or underestimated the uncertainty of risk assessment. In conclusion, we assessed the risk level of the 38 toxicants on the priority list developed by the WHO TobReg and provided a Korean-specific priority list for the regulations on the emission of cigarette smoke.

Distinct patterns of amyloid-dependent tau accumulation in Lewy body diseases.

BACKGROUND: In addition to Lewy body pathology, amyloid-ß plaques and neurofibrillary tangles that are characteristic for Alzheimer's disease are also frequently found in Lewy body diseases. OBJECTIVES: The objective of this study was to investigate tau accumulation patterns in dementia with Lewy bodies and other Lewy body diseases using in vivo 18 F-AV-1451 PET. METHODS: The study included 12 Parkinson's disease (PD) patients with normal cognition, 22 PD patients with cognitive impairment, and 18 dementia with Lewy bodies patients. In addition, 25 Alzheimer's disease patients and 25 healthy controls were included for comparison. All participants underwent 18 F-AV-1451 and 18 F-florbetaben PET scans, and cortical binding values were compared between the controls and each disease group. RESULTS: When compared with the controls, dementia with Lewy bodies patients showed slightly increased 18 F-AV-1451 binding in the primary sensorimotor and visual cortices and the parieto-temporal cortices, which failed to survive multiple comparisons. Amyloid-positive dementia with Lewy bodies patients showed significantly increased binding in the same regions when compared with controls, and even greater binding in the primary sensorimotor and visual cortices than Alzheimer's disease. Meanwhile, binding in the lateral and medial temporal cortices was less prominent than in Alzheimer's disease. In dementia with Lewy bodies, 18 F-AV-1451 binding in the occipital cortex correlated with 18 F-florbetaben binding. Amyloid-negative patients with normal cognition, patients with cognitive impairment, and dementia with Lewy bodies patients did not show increased 18 F-AV-1451 binding. CONCLUSIONS: Dementia with Lewy bodies patients may harbor 18 F-AV-1451 binding patterns distinct from Alzheimer's disease, with greater involvement of the primary cortices and less involvement of the temporal cortex. Tau burden increases in the Lewy body disease spectrum, and amyloid may play an important role in the accumulation of neocortical tau in Lewy body diseases. © 2017 International Parkinson and Movement Disorder Society.

Quantitative analysis of menthol and identification of other flavoring ingredients in capsule cigarettes marketed in Korea.

Currently, capsule cigarettes have been introduced by tobacco industries and their sales have increased exponentially. However, the capsule flavoring ingredients and their safety are still unknown. Although the contents of menthol and other ingredients directly added to cigarettes have been determined extensively, no analogous study exists for menthol-containing cigarette capsules. Basic physical properties of capsules in all 31 different capsule cigarettes commercially available in Korea were investigated, and their menthol contents were determined in this study. Other ingredients in these capsules were also qualitatively analyzed; methyl octanoate, menthone and isopulegol as well as menthol were detected in all the capsules. There is considerable variability in basic physical properties and menthol contents of cigarette capsules depending on their brand styles. The menthol contents of capsules and whole cigarettes are similar or higher than those previously reported for conventional menthol cigarettes. This is the first report on the physical properties of capsules and the fact that a wide range of menthol contents in capsule cigarettes, regardless of flavor types, allows smokers to select menthol content to their liking.

Mixture risk assessment of selected mainstream cigarette smoke constituents generated from low-yield cigarettes in South Korean smokers.

A total of 38 hazardous constituents in mainstream cigarette smoke of low-yield cigarettes sold in Korea were selected and analyzed using established methods. Risk calculations were performed using risk algorithms employed in previous studies and Korean population-based exposure parameters. The median cumulative incremental lifetime cancer risk of male smokers could vary from 828 × 10-6 to 2510 × 10-6, and that of female smokers could range from 440 × 10-6 to 1300 × 10-6, depending on the smoking regimens. The median hazard index as the sum of hazard quotients of male smokers varied from 367 to 1,225, and that of female smokers varied from 289 to 970, depending on the smoking regimens. The sensitivity analysis for this risk assessment indicated that the constituent yields in mainstream cigarette smoke, average number of cigarettes smoked per day or year, and mouth-spill rate are the main risk factors. Statistical positive correlations between the average daily dose calculated by the exposure algorithm used in this study for individual smokers and biomarkers verified the reliability of this assessment. It could be concluded that inhalation of the constituents present in the mainstream of low-yield cigarettes has significant cancer and non-cancer health risks, although its effect on risk reduction is still unknown under the fixed machine-smoking conditions.

Subcortical 18 F-AV-1451 binding patterns in progressive supranuclear palsy.

BACKGROUND: Accumulation of cortical and subcortical tau pathology is the primary pathological substrate for progressive supranuclear palsy (PSP). 18 F-AV-1451, a radiotracer that binds to the pathological tau protein, may be helpful for in vivo visualization and quantitation of tau pathology in PSP. OBJECTIVES: The objectives of this study were to investigate cortical and subcortical 18 F-AV-1451 binding patterns in patients with PSP. METHODS: We recruited 14 PSP patients and compared their cortical and subcortical binding patterns in 18 F-AV-1451 positron emission tomography (PET) studies with those of 15 Parkinson's disease (PD) patients and 15 healthy controls. RESULTS: In both the PD and PSP groups, subcortical 18 F-AV-1451 binding did not correlate with the severity of motor dysfunctions, and cortical binding did not differ between the controls and each patient group. However, the PSP patients showed greater 18 F-AV-1451 binding in the putamen, globus pallidus, subthalamic nucleus, and dentate nucleus when compared with the controls, whereas the PD patients showed lower 18 F-AV-1451 binding in the substantia nigra than controls. CONCLUSIONS: The PSP and PD patients showed distinct subcortical 18 F-AV-1451 binding patterns reflecting subcortical tau pathology in PSP and reduced nigral neuromelanin in PD. However, there was no correlation with the severity of motor dysfunction, no cortical regions with increased binding in PSP patients, and variable degrees of subcortical binding even in the controls. Therefore, the 18 F-AV-1451 PET may be less than ideal for assessing tau pathology in PSP. Further studies will be required to validate the clinical correlation and to understand the clinical utility of 18 F-AV-1451 PET for PSP patients. © 2016 International Parkinson and Movement Disorder Society.

Paroxysmal freezing of gait in a patient with mesial frontal transient ischemic attacks.

BACKGROUND: Rare patients have been reported who developed a mixture of gait disturbances following a focal lesion in the frontal lobe. Thus, the exact location of frontal lesion responsible for a specific gait disturbance is not well defined. CASE PRESENTATION: We describe a 47-year-old man who experienced two episodes of paroxysmal freezing of gait of the right leg. During the attacks, he had no motor weakness, sensory change, or disequilibrium. He had past history of panic attacks. Recently, he had been under severe emotional stress. T2 and diffusion brain magnetic resonance imaging scans were normal. So far, the most likely clinical diagnosis might be functional freezing of gait. However, magnetic resonance angiography showed atherosclerosis in the proximal left anterior cerebral artery. Perfusion scans showed a delayed mean transit time in the left mesial frontal lobe. He developed two more attacks during the four months of follow up. CONCLUSIONS: The presented case illustrates that the mesial frontal lobe may be important in the pathophysiology of freezing of gait. We speculate that the supplementary motor area may generate a neuronal command for the initiation of locomotion that in our case may have been inhibited by a transient ischemia.

Parkinsonian Patients with Striatal Cribriform State Present Rapidly Progressive Axial Parkinsonism.

OBJECTIVE: To define the significance of striatal cribriform state (SCS) observed in patients with primary progressive parkinsonism. METHODS: We reviewed medical records and brain magnetic resonance imaging studies of 1,260 patients with primary progressive parkinsonism. We identified 23 patients with SCS and analyzed their clinical features. RESULTS: All 23 patients had rapidly progressive parkinsonism predominated by postural instability and gait disturbance. Clinical features of 18 of the 23 patients were compatible with progressive supranuclear palsy (PSP); 2 patients were compatible with parkinsonian type multiple system atrophy; 2 patients were compatible with mixed clinical features of both; and 1 patient had PSP-like clinical features. CONCLUSIONS: Most parkinsonian patients with SCS present rapidly progressive parkinsonism predominated by postural instability and gait disturbance. SCS observed in patients with parkinsonism does not seem to be a coincidental finding associated with the generalized cerebrovascular process.

Participant roles in peer-victimization among young children in South Korea: Peer-, self-, and teacher-nominations.

This study explored participant roles in aggressive behavior among 95 children aged five to seven years, in a collectivistic culture, South Korea. Using a short-term longitudinal design, three types of nomination (peer, self, and teacher) were obtained for four participant roles (aggressor, victim, defender-stop, and defender-tell) and for four types of aggression (physical, verbal, social exclusion and rumor spreading). Assessments were made of stability of participant roles over time; inter-rater concordance among informants; discriminability; and relationships with sex, and likeability. Children tended to report themselves as victim and their peers as aggressors, especially for social exclusion. Nominations for aggressor showed highest stability over time and inter-rater concordance. Social exclusion showed different characteristics from other types of aggressive behavior in terms of its frequency and inter-rater concordance of role nominations. The type of defender (defender-stop or defender-tell) had different correlates with likeability. Findings are discussed in relation to different perspectives on social exclusion, and the defender role. Some different findings related specifically to social exclusion may be related to the particular nature of aggression or wang-ta in South Korea.

Seroprevalence of Trichinella sp. in Wild Boars (Sus scrofa) from Yanggu-gun, Gangwon-do, Korea.

A total 7 outbreaks of trichinellosis have occurred in Korea, mostly as a result of consumption of raw wild boar (Sus scrofa) meat. Since only 1 serological survey on wild boars had yet been performed in Korea, the present study aimed to estimate the prevalence of trichinellosis in wild boars and some species of rodents by artificial digestion and serological examinations in Yanggu-gun, Gangwon-do, the endemic area of trichinellosis. Both the wild boar and rodent muscle samples revealed no Trichinella larvae by direct examination and artificial digestion method. However, serological examinations revealed that 4 wild boar sera samples out of 118 (3.4%) were positive to Trichinella antigen. Although the recovery of Trichinella larvae ended in a failure, it is proved for the first time that the sylvatic cycle of Trichinella has been maintained in wild boars of Gangwon-do, Korea.

Effects of environmental temperature change on mercury absorption in aquatic organisms with respect to climate warming.

Because of global warming, the quantity of naturally generated mercury (Hg) will increase, subsequently methylation of Hg existing in seawater may be enhanced, and the content of metal in marine products rise which consequently results in harm to human health. Studies of the effects of temperatures on Hg absorption have not been adequate. In this study, in order to observe the effects of temperature changes on Hg absorption, inorganic Hg or methylmercury (MeHg) was added to water tanks containing loaches. Loach survival rates decreased with rising temperatures, duration, and exposure concentrations in individuals exposed to inorganic Hg and MeHg. The MeHg-treated group died sooner than the inorganic Hg-exposed group. The total Hg and MeHg content significantly increased with temperature and time in both metal-exposed groups. The MeHg-treated group had higher metal absorption rates than inorganic Hg-treated loaches. The correlation coefficients for temperature elevation and absorption were significant in both groups. The results of this study may be used as basic data for assessing in vivo hazards from environmental changes such as climate warming.

Carboplatin synergistically triggers the efficacy of photodynamic therapy via caspase 3-, 8-, and 12-dependent pathways in human anaplastic thyroid cancer cells.

Anaplastic thyroid cancer is one of the most aggressive forms of malignancies which grow very rapidly. Several conventional methods have been applied for the treatment of anaplastic thyroid cancer, but most of them were not successful in complete recovery of the patients. Therefore, a combination of two or more conventional modalities is being applied nowadays for the treatment of this type of cancer. In this present study, the combination of photodynamic therapy (PDT) and chemotherapy has been studied in anaplastic thyroid cancer. Human anaplastic thyroid cancer cells FRO were treated with a chemotherapy drug, carboplatin (cis-diammine-1,1-cyclobutanedicarboxyl-ateplatinum II (CBDCA)), and radachlorin-mediated PDT individually and in combination. Several parameters like cytotoxicity assay by MTT, apoptosis study by annexin V and propidium iodide, cell cycle analysis by flow cytometry, confocal microscopic study, and Western blot analysis for different apoptosis-related proteins like Bax, cytochrome c, caspases 3, 9, 8, and 12, etc. were studied to check the efficacy of the combination treatment as well as to find out the mechanism of this enhanced efficacy. Results showed that both PDT and CBDCA can induce apoptosis in FRO cells. However, a synergistic efficacy was observed when the cells were treated with CBDCA and PDT in combination. Changes in mitochondrial membrane potential and an increase in reactive oxygen species generation were observed in combination treatments. The enhanced expression of different apoptotic pathway-related proteins like Bax, cytochrome c, caspase 3, caspase 8, caspase 12, etc. also confirmed the higher efficacy of combination treatment. Therefore, with this combination treatment, not only a higher efficacy can be achieved but also the effective dose of the chemotherapy drug can be reduced, and hence, the adverse side effects of the chemotherapy drugs can also be controlled.

Response characterization of a fiber optic sensor array with dye-coated planar waveguide for detection of volatile organic compounds.

We have developed a multi-array side-polished optical-fiber gas sensor for the detection of volatile organic compound (VOC) gases. The side-polished optical-fiber coupled with a polymer planar waveguide (PWG) provides high sensitivity to alterations in refractive index. The PWG was fabricated by coating a solvatochromic dye with poly(vinylpyrrolidone). To confirm the effectiveness of the sensor, five different sensing membranes were fabricated by coating the side-polished optical-fiber using the solvatochromic dyes Reinhardt's dye, Nile red, 4-aminophthalimide, 4-amino-N-methylphthalimide, and 4-(dimethylamino)cinnamaldehyde, which have different polarities that cause changes in the effective refractive index of the sensing membrane owing to evanescent field coupling. The fabricated gas detection system was tested with five types of VOC gases, namely acetic acid, benzene, dimethylamine, ethanol, and toluene at concentrations of 1, 2,…,10 ppb. Second-regression and principal component analyses showed that the response properties of the proposed VOC gas sensor were linearly shifted bathochromically, and each gas showed different response characteristics.

Nitrate formation mechanisms causing high concentration of PM2.5 in a residential city with low anthropogenic emissions during cold season.

During the cold season in South Korea, NO3- concentrations are known to significantly increase, often causing PM2.5 to exceed air quality standards. This study investigated the formation mechanisms of NO3- in a suburban area with low anthropogenic emissions. The average PM2.5 was 25.3 µg m-3, with NO3- identified as the largest contributor. Ammonium-rich conditions prevailed throughout the study period, coupled with low atmospheric temperature facilitating the transfer of gaseous HNO3 into the particulate phase. This result indicates that the formation of HNO3 played a crucial role in determining particulate NO3- concentration. Nocturnal increases in NO3- were observed alongside increasing ozone (O3) and relative humidity (RH), emphasizing the significance of heterogeneous reactions involving N2O5. NO3- concentrations at the study site were notably higher than in Seoul, the upwind metropolitan area, during a high concentration episode. This difference could potentially attributed to lower local NO concentrations, which enhanced the reaction between O3 and NO2, to produce NO3 radicals. High concentrations of Cl- and dust were also identified as contributors to the elevated NO3- concentrations.

Fiber-optic multi-sensor array for detection of low concentration volatile organic compounds.

In this paper, we proposed a new type high sensitive volatile organic compounds (VOCs) gas sensor array that is based on the pulse width modulation technique. Four different types of solvatochromic dyes and two different types of polymers, were used to make the five different types of sensing membranes. These were deposited on the five side-polished optical fibers by a spin coater to make the five different sensing elements of the array. In order to ascertain the effectiveness of the sensors, five VOC gases were tested. Finally, principal component analysis (PCA) has been used to discriminates different types of VOCs.

Spargana in a weasel, Mustela sibirica manchurica, and a wild boar, Sus scrofa, from Gangwon-do, Korea.

To know the status of sparganum (plerocercoid of Spirometra erinacei) infection in the Korean wild life, several species of wild animals were captured in Gangwon-do and examined for their status of infection with spargana. From February to December 2011, a total of 62 wild boars, 5 badgers, 1 weasel, 1 Siberian chipmunk, and 53 wild rodents were captured, and their whole muscles were examined with naked eyes for the presence of spargana worms. From the weasel and 1 wild boar, a total of 5 spargana specimens were extracted. The weasel was for the first time recorded as an intermediate or paratenic/transport host of S. erinacei in Korea, and both the weasel (Mustela sibirica manchurica) and wild boar (Sus scrofa) were added to the list of wild animals carrying spargana.

Trichinosis caused by ingestion of raw soft-shelled turtle meat in Korea.

Reptiles, unlike mammals, have been considered to be unsuitable hosts of Trichinella spp., though larvae have been detected in their muscles and human outbreaks related to their consumption have, in fact, occurred. Herein we report 2 Korean cases of trichinosis, possibly transmitted via consumption of reptile meat. Both patients suffered from myalgia, headache, and facial edema. Laboratory examinations revealed leukocytosis with eosinophilia (54% and 39%, respectively) and elevated creatinine phosphokinase. ELISA was performed under the suspicion of trichinosis, showing positivity at the 29th and 60th day post-infection. Since they had consumed raw soft-shelled turtle meat, turtle was strongly suggested to be an infection source of trichinosis in Korea next to the wild boar and badger.

Population-level call properties of endangered Dryophytes suweonensissensu lato (Anura: Amphibia) in South Korea.

Calling is one of the unique amphibian characteristics that facilitates social communication and shows individuality; however, it also makes them vulnerable to predators. Researchers use amphibian call properties to study their population status, ecology, and behavior. This research scope has recently broadened to species identification and taxonomy. Dryophytes flaviventris has been separated from the endangered anuran species, D. suweonensis, based on small variations in genetic, morphometric, and temporal call properties observed in South Korea. The Chilgap Mountain (CM) was considered as the potential geographic barrier for the speciation. However, it initiated taxonomic debates as CM has been hardly used and is considered a potential barrier for other species. The calls of populations from both sides are also apparently similar. Thus, to verify the differences in call properties among populations of D. suweonensis sensu lato (s.l.; both of the species), we sampled and analyzed call data from five localities covering its distribution range, including the southern (S) and northern (N) parts of CM. We found significant differences in many call properties among populations; however, no specific pattern was observed. Some geographically close populations, such as Iksan (S), Wanju (S), and Gunsan (S), had significant differences, whereas many distant populations, such as Pyeongtaek (N) and Wanju (S), had no significant differences. Considering the goal of this study was only to observe the call properties, we cautiously conclude that the differences are at the population level rather than the species level. Our study indicates the necessity of further investigation into the specific status of D. flaviventris using robust integrated taxonomic approaches, including genetic and morphological parameters from a broader array of localities.