Spatial and PMF analysis of particle size distributions simultaneously measured at four locations at the roadside of highways

In urban areas, particulate matter emitted from vehicles directly affects the health of citizens near roads. Thus, in this study, particle size distribution was measured by the horizontal and vertical distances along a highway road with heavy traffic to characterize the dispersion phenomena of particulate matter emitted from vehicles. In addition, the contribution of pollution sources was analyzed using a source-receptor model. A concentration gradient was observed in which the concentration decreased with the increase in the distance from the road when the wind blew from the road to the monitoring locations. The concentration was slightly higher within 50 m of the road when the wind blows parallel to the road, and similar concentrations were found at the other monitoring locations further away from the roads. In particular, the higher the turbulence intensity of the wind, the lower is the concentration gradient coefficient because of the more enhanced mixing and dispersion. A positive matrix factorization (PMF) model with the measured particle size distribution data in the range of 9-300 nm resulted in a contribution of about 70 % (number) and 20 % (mass) to particle concentrations because of six types of vehicles including LPG, two gasoline vehicles (GDI, MPI), and three diesel vehicles with 3rd, 4th, and 5th emission classes. It showed a decrease in the vehicular contribution as the distance from the road increased. Particle number concentrations decreased with increasing altitude up to 30 m above the ground. The results of this study can be useful in deriving generalized gradient equations of particle concentrations exposed by distance and wind direction at the roadside using traffic and meteorological conditions and for establishing environmental policies, such as roadside exposure assessment, in the future. A CAPSULE ABSTRACT: Dispersion of particles emitted from vehicles on a busy highway was characterized by roadside measurements of horizontal and vertical profiles of particle size distributions measured at four locations. The source profiles and contributions were estimated by major sources using a source-receptor model such as PMF.

Biokinetics of subacutely co-inhaled same size gold and silver nanoparticles

BACKGROUND

Toxicokinetics of nanomaterials, including studies on the absorption, distribution, metabolism, and elimination of nanomaterials, are essential in assessing their potential health effects. The fate of nanomaterials after inhalation exposure to multiple nanomaterials is not clearly understood.

METHODS

Male Sprague-Dawley rats were exposed to similar sizes of silver nanoparticles (AgNPs, 10.86 nm) and gold nanoparticles (AuNPs, 10.82 nm) for 28 days (6-h/day, 5-days/week for four weeks) either with separate NP inhalation exposures or with combined co-exposure in a nose-only inhalation system. Mass concentrations sampled from the breathing zone were AuNP 19.34 ± 2.55 μg/m³ and AgNP 17.38 ± 1.88 μg/m³ for separate exposure and AuNP 8.20 μg/m³ and AgNP 8.99 μg/m³ for co-exposure. Lung retention and clearance were previously determined on day 1 (6-h) of exposure (E-1) and on post-exposure days 1, 7, and 28 (PEO-1, PEO-7, and PEO-28, respectively). In addition, the fate of nanoparticles, including translocation and elimination from the lung to the major organs, were determined during the post-exposure observation period.

RESULTS

AuNP was translocated to the extrapulmonary organs, including the liver, kidney, spleen, testis, epididymis, olfactory bulb, hilar and brachial lymph nodes, and brain after subacute inhalation and showed biopersistence regardless of AuNP single exposure or AuNP + AgNP co-exposure, showing similar elimination half-time. In contrast, Ag was translocated to the tissues and rapidly eliminated from the tissues regardless of AuNP co-exposure. Ag was continually accumulated in the olfactory bulb and brain and persistent until PEO-28.

CONCLUSION

Our co-exposure study of AuNP and AgNP indicated that soluble AgNP and insoluble AuNP translocated differently, showing soluble AgNP could be dissolved into Ag ion to translocate to the extrapulmonary organs and rapidly removed from most organs except the brain and olfactory bulb. Insoluble AuNPs were continually translocated to the extrapulmonary organs, and they were not eliminated rapidly.

The Acute and Short-Term Inhalation of Carbon Nanofiber in Sprague-Dawley Rats

The inhalation toxicity of carbon nanofibers (CNFs) is not clearly known due to relatively few related studies reported. An acute inhalation study and short-term inhalation study (5 days) were therefore conducted using Sprague-Dawley rats. In the acute inhalation study, the rats were grouped and exposed to a fresh air control or to low (0.238 ± 0.197), moderate (1.935 ± 0.159), or high (24.696 ± 6.336 mg/m³) CNF concentrations for 6 h and thereafter sacrificed at 14 days. For the short-term inhalation study, the rats were grouped and exposed to a fresh air control or low (0.593 ± 0.019), moderate (2.487 ± 0.213), or high (10.345 ± 0.541 mg/m³) CNF concentrations for 6 h/day for 5 days and sacrificed at 1, 3, and 21 days post-exposure. No mortality was observed in the acute inhalation study. Thus, the CNF LC₅₀ was higher than 25 mg/m³. No significant body or organ weight changes were noted during the 5 days short-term inhalation study or during the post-exposure period. No significant effects of toxicological importance were observed in the hematological, blood biochemical, and coagulation tests. In addition, the bronchoalveolar lavage (BAL) fluid cell differential counts and BAL inflammatory markers showed no CNF-exposure-relevant changes. The histopathological examination also found no CNF-exposure-relevant histopathological lesions. Thus, neither acute nor 5 days inhalation exposure to CNFs induced any noticeable toxicological responses.

1602 A Quality Improvement Project on The Management of Patients with Traumatic Head Injury Presenting to A District General Hospital

Introduction

Traumatic Brain Injury (TBI) is associated with morbidity and mortality. All District General Hospitals (DGH) in West Midlands liaise with Neurosurgery centres for management of these patients through a referral system (NORSe). The aim of this study was to assess outcomes in TBI following the implementation of vital interventions.

Method

A retrospective data was collected between 1/1/2019 and 1/12/2020. We included all patients admitted with traumatic brain injury over the age of 16. We accessed the data from the hospital database, clinical notes, and NORSe. A re-audit was performed following implementations of recommendations (proforma and care of elderly input). Further data were collected prospectively.

Results

Our cohort included n1=61 patients (first cycle) and n2= 29 (second cycle). The demographic age and gender were comparable in both cycles. The median time for Neurosurgery advice was 229 minutes (IQR 60-690) in the first cycle as compared to 80 minutes (IQR 40-120, P < 0.05) and the main cause for delay was inadequate information transfer. The mortality rate was 24% (5 were attributed to sepsis), as compared to 14% in the second cycle. The median length of stay (LOS) was 4 days (IQR 3-13.5) in the first cycle, which translates to a cost of £26,815 per quarter. In comparison, LOS was 3 days (IQR 2-4), which translates to the cost of bed occupancy of £12,771 and saving of £14,043 per quarter, in the second cycle.

Conclusions

The introduction of simple interventions in a DGH can help to significantly improve patient outcomes in those admitted with Traumatic brain injury.

822 Lessons Learnt During the COVID-19 Pandemic on Emergency Surgical Admissions in A District General Hospital

Introduction

Coronavirus disease (COVID-19) is an acute severe respiratory distress syndrome which resulted in an unprecedented impact on NHS service provision. We aimed to assess the impact of COVID-19 on general surgical services in a district general hospital.

Method

Electronic health care record data was retrospectively collected from 6th of April to 6th of May for both 2019 and 2020.

Results

Despite fewer referrals and admissions in 2020 (133 vs 177 admissions in 2019), there were more failed discharges (29 vs 17 in 2019) and higher associated costs. Higher numbers of biliary related pathologies and pancreatitis (50 in 2020 vs 25 in 2019), and fewer complaints of non-specific abdominal pain (10 in 2020 vs 22 in 2019) were observed. The use of outpatient investigations decreased by approximately 40% in 2020; however, utilisation of inpatient investigations was comparable.

Conclusions

Better utilisation of outpatient investigations and virtual clinic services may surmount pressures from further peaks of COVID-19. The increase in biliary related cases and pancreatitis may be consequent upon lifestyle changes during lockdown. This merits further investigation and if appropriate, public health intervention. In the absence of an efficacious vaccine, further research would be essential to streamline general surgical services based on clinical risk stratification.

Lung retention and particokinetics of silver and gold nanoparticles in rats following subacute inhalation co-exposure

Background

Inhalation exposure to nanomaterials in workplaces can include a mixture of multiple nanoparticles. Such ambient nanoparticles can be of high dissolution or low dissolution in vivo and we wished to determine whether co-exposure to particles with different dissolution rates affects their biokinetics.

Methods and Results

Rats were exposed to biosoluble silver nanoparticles (AgNPs, 10.86 nm) and to biopersistent gold nanoparticles (AuNPs, 10.82 nm) for 28 days (6-h/day, 5-days/week for 4 weeks) either with separate NP inhalation exposures or with combined co-exposure. The separate NPs mass concentrations estimated by the differential mobility analyzer system (DMAS) were determined to be 17.68 ± 1.69 μg/m³ for AuNP and 10.12 ± 0.71 μg/m³ for AgNP. In addition, mass concentrations analyzed by atomic absorption spectrometer (AAS) via filter sampling were for AuNP 19.34 ± 2.55 μg/m³ and AgNP 17.38 ± 1.88 μg/m³ for separate exposure and AuNP 8.20 ± 1.05 μg/m³ and AgNP 8.99 ± 1.77 μg/m³ for co-exposure. Lung retention and clearance were determined on day 1 (6-h) of exposure (E-1) and on post-exposure days 1, 7, and 28 (PEO-1, PEO-7, and PEO-28, respectively). While the AgNP and AuNP deposition rates were determined to be similar due to the similarity of NP size of both aerosols, the retention half-times and clearance rates differed due to the difference in dissolution rates. Thus, when comparing the lung burdens following separate exposures, the AgNP retention was 10 times less than the AuNP retention at 6-h (E-1), and 69, 89, and 121 times lower less than the AuNP retention at PEO-1, PEO-7, and PEO-28, respectively. In the case of AuNP+AgNP co-exposure, the retained AgNP lung burden was 14 times less than the retained AuNP lung burden at E-1, and 26, 43, and 55 times less than the retained AuNP lung burden at PEO-1, PEO-7, and PEO-28, respectively. The retention of AuNP was not affected by the presence of AgNP, but AgNP retention was influenced in the presence of AuNP starting at 24 h after the first day of post day of exposure. The clearance of AgNPs of the separate exposure showed 2 phases; fast (T_1/2 3.1 days) and slow (T_1/2 48.5 days), while the clearance of AuNPs only showed one phase (T_1/2 .81.5 days). For the co-exposure of AuNPs+AgNPs, the clearance of AgNPs also showed 2 phases; fast (T_1/2 2.2 days) and slow (T_1/2 28.4 days), while the clearance of AuNPs consistently showed one phase (T_1/2 54.2 days). The percentage of Ag lung burden in the fast and slow clearing lung compartment was different between separate and combined exposure. For the combined exposure, the slow and fast compartments were each 50% of the lung burden. For the single exposure, 1/3 of the lung burden was cleared by the fast rate and 2/3 of the lung burden by the slow rate.

Conclusions

The clearance of AgNPs follows a two- phase model of fast and slow dissolution rates while the clearance of AuNPs could be described by a one- phase model with a longer half-time. The co-exposure of AuNPs+AgNPs showed that the clearance of AgNPs was altered by the presence of AuNPs perhaps due to some interaction between AgNP and AuNP affecting dissolution and/or mechanical clearance of AgNP in vivo.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-021-00397-z.

Even lobar deposition of poorly soluble gold nanoparticles (AuNPs) is similar to that of soluble silver nanoparticles (AgNPs)

Background

Information on particle deposition, retention, and clearance is important when evaluating the risk of inhaled nanomaterials to human health. The revised Organization Economic Cooperation and Development (OECD) inhalation toxicity test guidelines now require lung burden measurements of nanomaterials after rodent subacute and sub-chronic inhalation exposure (OECD 412, OECD 413) to inform on lung clearance behavior and translocation after exposure and during post-exposure observation (PEO). Lung burden measurements are particularly relevant when the testing chemical is a solid poorly soluble nanomaterial. Previously, the current authors showed that total retained lung burden of inhaled soluble silver nanoparticles (AgNPs) could be effectively measured using any individual lung lobe.

Methods and results

Accordingly, the current study investigated the evenness of deposition/retention of poorly soluble gold nanoparticles (AuNPs) after 1 and 5 days of inhalation exposure. Rats were exposed nose-only for 1 or 5 days (6 h/day) to an aerosol of 11 nm well-dispersed AuNPs. Thereafter, the five lung lobes were separated and the gold concentrations measured using an inductively coupled plasma-mass spectrophotometer (ICP-MS). The results showed no statistically significant difference in the AuNP deposition/retention among the different lung lobes in terms of the gold mass per gram of lung tissue.

Conclusions

Thus, it would seem that any rat lung lobe can be used for the lung burden analysis after short or long-term NP inhalation, while the other lobes can be used for collecting and analyzing the bronchoalveolar lavage fluid (BALF) and for the histopathological analysis. Therefore, combining the lung burden measurement, histopathological tissue preparation, and BALF assay from one rat can minimize the number of animals used and maximize the number of endpoints measured.

Mode of silver clearance following 28-day inhalation exposure to silver nanoparticles determined from lung burden assessment including post-exposure observation periods

Recently revised OECD inhalation toxicity testing guidelines require measurements of lung burden immediately after and for periods following exposure for nanomaterials. Lung burden is a function of pulmonary deposition and retention of nanoparticles. Using lung burden studies as per OECD guidelines, it may be possible to assess clearance mechanisms of nanoparticles. In this study, male rats were exposed to silver nanoparticle (AgNP) aerosols (18.1-19.6 nm) generated from a spark generator. Exposure groups consisted of (1) control (fresh air), (2) low (31.2 ± 8.5 µg/m³), (3) moderate (81.8 ± 11.4 µg/m³), and (4) high concentrations (115.6 ± 30.5 µg/m³). Rats were exposed for 6-h/day, 5-days/week for 4 weeks (28-days) based on the revised OECD test guideline 412. Bronchoalveolar lavage (BAL) fluids were collected on post-exposure observation (PEO)-1 and PEO-7 days and analyzed for inflammatory cells and inflammatory biomarkers. The lung burdens of Ag from AgNPs were measured on PEO-1, PEO-7, and PEO-28 days to obtain quantitative mass concentrations per lung. Differential counting of blood cells and inflammatory biomarkers in BAL fluid and histopathological evaluation of lung tissue indicated that exposure to the high concentrations of AgNP aerosol induced inflammation at PEO-1, slowly resolved at PEO-7 and completely resolved at PEO-28 days. Lung burden measurement suggested that Ag from AgNPs was cleared through two different modes; fast and slow clearance. The fast clearance component was concentration-dependent with half-times ranging from two to four days and clearance rates of 0.35-0.17/day^-1 from low to high concentrations. The slow clearance had half-times of 100, 57, and 76 days and clearance rates of 0.009, 0.012, and 0.007/day^-1 for the high, moderate and low concentration exposure. The exact mechanism of clearance is not known currently. The fast clearance component which was concentration-dependent could be dependent on the dissolution of AgNPs and the slow clearance would be due to slow clearance of the low dissolution AgNPs secondary particles originating from silver ions reacting with biogenic anions. These secondary AgNPs might be cleared by mechanisms other than dissolution such as mucociliary escalation, translocation to the lymphatic system or other organs.

28-Day inhalation toxicity study with evaluation of lung deposition and retention of tangled multi-walled carbon nanotubes

Lung deposition and retention measurements are now required by the newly revised OECD inhalation toxicity testing guidelines 412 and 413 when evaluating the clearance and biopersistence of poorly soluble nanomaterials, such as multi-walled carbon nanotubes (MWCNTs). However, evaluating the lung deposition concentration is challenging with certain nanomaterials, such as carbon-based and iron-based nanomaterials, as it is difficult to differentiate them from endogenous elements. Therefore, the current 28-day inhalation toxicity study investigated the lung retention kinetics of tangled MWCNTs. Male Sprague Dawley rats were exposed to MWCNTs at 0, 0.257, 1.439, and 4.253 mg/m³ for 28 days (6 h/day, 5 days/week, 4 weeks). Thereafter, the rats were sacrificed at day 1, 7, and 28 post-exposure and the pulmonary inflammatory response evaluated by analyzing the bronchoalveolar lavage fluid. Plus, the blood biochemistry, hematology, and histopathology of the lungs were also examined. The lung deposition and retention of MWCNTs were determined based on the elemental carbon content in the lungs after tissue digestion. The number of polymorphonuclear cells and LDH concentration were both found to be significantly higher with the medium and high concentrations (1.439 and 4.253 mg/m³) and dose dependent. The estimated retention half-life for the high concentration (4.253 mg/m³) was about 35 days. The results of this study indicate that tangled MWCNTs seem to have a relatively shorter retention half-life when compared to previous reports on rigid MWCNTs, and the no-observed adverse effect level (NOAEL) for the tested tangled MWCNTs was 0.257 mg/m³ in a previous rat 28-day subacute inhalation toxicity study.

Lobar evenness of deposition/retention in rat lungs of inhaled silver nanoparticles: an approach for reducing animal use while maximizing endpoints

BACKGROUND

Information on particle deposition, retention and clearance are important for the evaluation of the risk of inhaled nanomaterials to human health. Recent revised OECD inhalation toxicity test guidelines require to evaluate the lung burden of nanomaterials after rodent subacute and subchronic inhalation exposure (OECD 412, OECD 413). These revised test guidelines require additional post-exposure observation (PEO) periods that include lung burden measurements that can inform on lung clearance behavior and translocation. The latter being particularly relevant when the testing chemical is a solid poorly soluble nanomaterial. Therefore, in the spirit of 3 R's, we investigated whether measurement of retained lung burden of inhaled nanoparticles (NPs) in individual lung lobes is sufficient to determine retained lung burden in the total lung. If it is possible to use only one lobe, it will reduce animal use and maximize the number of endpoints evaluated.

RESULTS

To achieve these goals, rats were exposed nose-only for 1 or 5 days (6 h/day) to an aerosol of 20 nm well-dispersed silver nanoparticles (AgNPs), which is the desired particle diameter resulting in maximum deposition in the pulmonary region when inhaled as singlets. After exposure, the five lung lobes were separated and silver concentration was measured using inductively coupled plasma-mass spectrophotometer (ICP-MS). The results showed that the retention of deposited silver nanoparticle in the different lung lobes did not show any statistically significant difference among lung lobes in terms of silver mass per gram lung lobe. This novel finding of evenness of retention/deposition of inhaled 20 nm NPs in rats for all five lobes in terms of mass per unit tissue weight contrasts with earlier studies reporting greater apical lobe deposition of inhaled micro-particles in rodents. The difference is most likely due to preferred and efficient deposition of inhaled NPs by diffusion vs. additional deposition by sedimentation and impaction for micron-sized particles.

CONCLUSION

AgNPs following acute inhalation by rats are evenly retained in each lung lobe in terms of mass per unit lung tissue weight. Accordingly, we suggest sampling any of the rat lung lobes for lung burden analysis can be used to determine deposited or retained total lung burden after short-term inhalation of NPs and using the other lobes for collecting and analyzing bronchoalveolar lavage fluid (BALF) and for histopathological analysis. Therefore, by combining lung burden measurement, histopathological tissue preparation, and BALF assay in the same rat will reduce the number of animals used and maximize the number of endpoints measured.

Identification of atopic dermatitis phenotypes with good responses to probiotics (Lactobacillus plantarum CJLP133) in children

The therapeutic effect of probiotics in atopic dermatitis (AD) remains controversial and varies according to the individual patient. We aimed to identify a population of AD patients with a good clinical response to probiotic treatment. We recruited 76 children with a median age of 7.1 years who suffered from moderate to severe AD. After a 2-week washout period, all patients were given Lactobacillus plantarum CJLP133 at a dosage of 1×10¹⁰ colony-forming units once a day for 12 weeks. We measured eosinophil counts in the peripheral blood, the proportion of CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells in CD4⁺ T cells, serum total immunoglobulin E (IgE) levels, and specific IgE against common allergens before the start of the treatment (T1) and at discontinuation (T2). Responders were defined as patients with at least a 30% reduction in the SCORing of AD (SCORAD) index after treatment. There were 36 responders and 40 non-responders after probiotic treatment. The median SCORAD was reduced from 29.5 (range 20.6-46.3) at T1 to 16.4 (range 6.3-30.8) at T2 in the responder group (P<0.001). In multivariable logistic regression analysis, a good clinical response was significantly associated with high total IgE levels (aOR 5.1, 95% CI 1.1-23.6), increased expression of transforming growth factor (TGF)-β (aOR 4.6, 95% CI 1.3-15.9), and a high proportion of Treg cells in CD4⁺ T cells (aOR 3.7, 95% CI 1.1-12.7) at T1. In the responder group, the proportion of Treg cells was significantly increased after 12 weeks of treatment (P=0.004), while TGF-β mRNA expression was decreased (P=0.017). Our results suggest that a subgroup of patients with a specific AD phenotype showing an immunologically active state (high total IgE, increased expression of TGF-β, high numbers of Treg cells) may benefit from probiotic treatment with L. plantarum CJLP133.

Reliability and validity of the Atopic Dermatitis Symptom Score (ADSS)

BACKGROUND

We have developed the Atopic Dermatitis Symptom Score (ADSS) by which patients or parents can easily assess and record AD symptoms on a daily basis in a smartphone application. The aim of this study was to evaluate the reliability and validity of the ADSS.

METHODS

We enrolled 307 children and adolescents with AD. Parents or caregivers were asked to record daily symptoms of the patients (itching, sleep disturbance, erythema, dryness, oozing, and edema) using a scale of 0-4. Statistical analyses consisted of the test-retest reliability, concurrent validity, minimal clinically important difference (MCID), responsiveness, floor or ceiling effects, and screening accuracy. Receiver-operating characteristic analyses were conducted to evaluate the ADSS cutoff point for predicting severe AD (SCORing AD [SCORAD] ≥40).

RESULTS

Test-retest reliability between daytime and night-time ADSS was good (intraclass correlation coefficient, 0.82 [95% CI: 0.70-0.90]). An increase in ADSS was significantly associated with an increase in SCORAD (r = 0.64, P < .0001) (concurrent validity). The MCID was 4.1 points for the ADSS. There was a significant association between changes in ADSS and SCORAD (r = 0.56, P < .0001), indicating good responsiveness. At the optimal ADSS cutoff value of 7.0, sensitivity, specificity, and positive and negative predictive values were 88.4%, 78.6%, 21.1%, and 99.1%, respectively (screening accuracy).

CONCLUSIONS

The ADSS can be a useful tool for self-assessment of skin symptoms in children with AD.

A multicenter study on anaphylaxis caused by peanut, tree nuts, and seeds in children and adolescents

Peanut (PN) and tree nuts (TNs) are common causes of anaphylaxis in Western countries, but no information is available in Korea. To feature clinical characteristics of anaphylaxis caused by PN, TNs, and seeds, a retrospective medical record review was performed in 14 university hospitals in Korea (2009-2013). One hundred and twenty-six cases were identified, with the mean age of 4.9 years. PN, walnut (WN), and pine nut accounted for 32.5%, 41.3%, and 7.1%, respectively. The median values of specific IgE (sIgE) to PN, WN, and pine nut were 10.50, 8.74, and 4.61 kU_A /l, respectively. Among 50 cases managed in the emergency department, 52.0% were treated with epinephrine, 66.0% with steroid, 94.0% with antihistamines, 36.0% with oxygen, and 48.0% with bronchodilator. In conclusion, WN, PN, and pine nut were the three most common triggers of anaphylaxis in Korean children, and anaphylaxis could occur at remarkably low levels of sIgE.

Exposure monitoring of graphene nanoplatelets manufacturing workplaces

Graphenes have emerged as a highly promising, two-dimensional engineered nanomaterial that can possibly substitute carbon nanotubes. They are being explored in numerous R&D and industrial applications in laboratories across the globe, leading to possible human and environmental exposures to them. Yet, there are no published data on graphene exposures in occupational settings and no readily available methods for their detection and quantitation exist. This study investigates for the first time the potential exposure of workers and research personnel to graphenes in two research facilities and evaluates the status of the control measures. One facility manufactures graphene using graphite exfoliation and chemical vapor deposition (CVD), while the other facility grows graphene on a copper plate using CVD, which is then transferred to a polyethylene terephthalate (PET) sheet. Graphene exposures and process emissions were investigated for three tasks - CVD growth, exfoliation, and transfer - using a multi-metric approach, which utilizes several direct reading instruments, integrated sampling, and chemical and morphological analysis. Real-time instruments included a dust monitor, condensation particle counter (CPC), nanoparticle surface area monitor, scanning mobility particle sizer, and an aethalometer. Morphologically, graphenes and other nanostructures released from the work process were investigated using a transmission electron microscope (TEM). Graphenes were quantified in airborne respirable samples as elemental carbon via thermo-optical analysis. The mass concentrations of total suspended particulate at Workplaces A and B were very low, and elemental carbon concentrations were mostly below the detection limit, indicating very low exposure to graphene or any other particles. The real-time monitoring, especially the aethalometer, showed a good response to the released black carbon, providing a signature of the graphene released during the opening of the CVD reactor at Workplace A. The TEM observation of the samples obtained from Workplaces A and B showed graphene-like structures and aggregated/agglomerated carbon structures. Taken together, the current findings on common scenarios (exfoliation, CVD growth, and transfer), while not inclusive of all graphene manufacturing processes, indicate very minimal graphene or particle exposure at facilities manufacturing graphenes with good manufacturing practices.

Airborne formaldehyde causes skin barrier dysfunction in atopic dermatitis

BACKGROUND

It remains to be elucidated whether exposure to air pollutants aggravates atopic dermatitis (AD).

OBJECTIVES

This study aimed to evaluate the effects of exposure to formaldehyde for 1 h and 2 h on skin barrier function in both the control and the AD groups.

METHODS

In 41 patients with AD and 34 healthy children, a provocation test was performed in which two different areas of normal-appearing skin on the forearm were stimulated with airborne formaldehyde at 500 μg m(-3) or placebo for 2 h. We measured transepidermal water loss (TEWL) and skin pH, and calculated the percentage change from baseline.

RESULTS

Exposure to formaldehyde increased TEWL in the control group [P < 0·001; median of difference 1·4; interquartile range (IQR) 0·9-1·6] and in the AD group (P < 0·001; median of difference 2·5; IQR 2·0-3·6). The percentage change of TEWL after formaldehyde exposure in the AD group was higher than in the control group (P < 0·001), whereas exposure to placebo showed no differences between both groups. The AD group also demonstrated a higher percentage increase in skin pH after exposure to formaldehyde than the control group (P < 0·001).

CONCLUSIONS

Short-term exposure to formaldehyde causes skin barrier dysfunction in both healthy children and children with AD, and this effect is more prominent in children with AD.

28-Day inhalation toxicity of graphene nanoplatelets in Sprague-Dawley rats

Graphene, a two-dimensional engineered nanomaterial, is now being used in many applications, such as electronics, biological engineering, filtration, lightweight and strong nanocomposite materials, and energy storage. However, there is a lack of information on the potential health effects of graphene in humans based on inhalation, the primary engineered nanomaterial exposure pathway in workplaces. Thus, an inhalation toxicology study of graphene was conducted using a nose-only inhalation system for 28 days (6 h/day and 5 days/week) with male Sprague-Dawley rats that were then allowed to recover for 1-, 28-, and 90-day post-exposure period. Animals were separated into 4 groups (control, low, moderate, and high) with 15 male rats (5 rats per time point) in each group. The measured mass concentrations for the low, moderate, and high exposure groups were 0.12, 0.47, and 1.88 mg/m(3), respectively, very close to target concentrations of 0.125, 0.5, and 2 mg/m(3). Airborne graphene exposure was monitored using several real-time instrumentation over 10 nm to 20 μm for size distribution and number concentration. The total and respirable elemental carbon concentrations were also measured using filter sampling. Graphene in the air and biological media was traced using transmission electron microscopy. In addition to mortality and clinical observations, the body weights and food consumption were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for blood biochemical tests, and the organ weights were measured. No dose-dependent effects were recorded for the body weights, organ weights, bronchoalveolar lavage fluid inflammatory markers, and blood biochemical parameters at 1-day post-exposure and 28-day post-exposure. The inhaled graphenes were mostly ingested by macrophages. No distinct lung pathology was observed at the 1-, 28- and 90-day post-exposure. The inhaled graphene was translocated to lung lymph nodes. The results of this 28-day graphene inhalation study suggest low toxicity and a NOAEL of no less than 1.88 mg/m(3).

Common polygenic variation and risk for childhood-onset schizophrenia

Childhood-onset schizophrenia (COS) is a rare and severe form of the disorder, with more striking abnormalities with respect to prepsychotic developmental disorders and abnormities in the brain development compared with later-onset schizophrenia. We previously documented that COS patients, compared with their healthy siblings and with adult-onset patients (AOS), carry significantly more rare chromosomal copy number variations, spanning large genomic regions (>100 kb) (Ahn et al. 2014). Here, we interrogated the contribution of common polygenic variation to the genetic susceptibility for schizophrenia. We examined the association between a direct measure of genetic risk of schizophrenia in 130 COS probands and 103 healthy siblings. Using data from the schizophrenia and autism GWAS of the Psychiatric Genomic Consortia, we selected three risk-related sets of single nucleotide polymorphisms from which we conducted polygenic risk score comparisons for COS probands and their healthy siblings. COS probands had higher genetic risk scores of both schizophrenia and autism than their siblings (P<0.05). Given the small sample size, these findings suggest that COS patients have more salient genetic risk than do AOS.

Case study on risk evaluation of printed electronics using nanosilver ink

BACKGROUND

With the ever-increasing development of nanotechnology, our society is being surrounded by possible risks related to exposure to manufactured nanomaterials. The consumer market already includes many products that contain silver nanoparticles (AgNPs), including various household products, such as yoga mats, cutting boards, running shirts, and socks. There is a growing concern over the release of AgNPs in workplaces related to the manufacture and application of nanomaterials.

OBJECTIVE

This study investigated the release of AgNPs during the operation of a printed electronics printer.

METHODS

Using an exposure simulation chamber, a nanoparticle collector, scanning mobility particle sizer (SMPS), condensation particle counter (CPC), dust monitor, and mixed cellulose ester (MCE) filters are all connected to measure the AgNP exposure levels when operating a printed electronics printer.

RESULTS

A very small amount of AgNPs was released during the operation of the printed electronics printer, and the number of AgNPs inside the exposure simulation chamber was lower than that outside background. In addition, when evaluating the potential risks for consumers and workers using a margin of exposure (MOE) approach and target MOE of 1000, the operational results far exceeded the target MOE in this simulation study and in a previous workplace exposure study.

CONCLUSION

The overall results indicate a no-risk concern level in the case of printed electronics using nanosilver ink.

5-Day repeated inhalation and 28-day post-exposure study of graphene

Graphene has recently been attracting increasing attention due to its unique electronic and chemical properties and many potential applications in such fields as semiconductors, energy storage, flexible electronics, biosensors and medical imaging. However, the toxicity of graphene in the case of human exposure has not yet been clarified. Thus, a 5-day repeated inhalation toxicity study of graphene was conducted using a nose-only inhalation system for male Sprague-Dawley rats. A total of three groups (20 rats per group) were compared: (1) control (ambient air), (2) low concentration (0.68 ± 0.14 mg/m(3) graphene) and (3) high concentration (3.86 ± 0.94 mg/m(3) graphene). The rats were exposed to graphene for 6 h/day for 5 days, followed by recovery for 1, 3, 7 or 28 days. The bioaccumulation and macrophage ingestion of the graphene were evaluated in the rat lungs. The exposure to graphene did not change the body weights or organ weights of the rats after the 5-day exposure and during the recovery period. No statistically significant difference was observed in the levels of lactate dehydrogenase, protein and albumin between the exposed and control groups. However, graphene ingestion by alveolar macrophages was observed in the exposed groups. Therefore, these results suggest that the 5-day repeated exposure to graphene only had a minimal toxic effect at the concentrations and time points used in this study.

Selective inhibition of FAAH produces antidiarrheal and antinociceptive effect mediated by endocannabinoids and cannabinoid-like fatty acid amides

BACKGROUND

The endogenous cannabinoid system (ECS) plays a crucial role in multiple physiological processes in the central nervous system and in the periphery. The discovery that selective cannabinoid (CB) receptor agonists exert a potent inhibitory action on gastrointestinal (GI) motility and pain has placed the ECS in the center of attention as a possible target for the treatment of functional GI diseases. However, side effects of CB agonists prompted the search for novel therapeutic targets. Here, the effect of PF-3845, a potent and selective fatty acid amide hydrolase (FAAH) inhibitor in the GI tract was investigated.

METHODS

The effect of PF-3845 on GI motility was characterized in vitro and in vivo, using mouse models that mimic physiological and pathophysiological conditions. The antinociceptive action of PF-3845 was evaluated on the basis of behavioral pain models. Endocannabinoid degradation product levels after inhibition of FAAH were quantified using HPLC-MS/MS.

KEY RESULTS

PF-3845 significantly inhibited mouse colonic motility in vitro and in vivo. Selective inhibition of FAAH reversed hypermotility and reduced pain in mouse models mimicking functional GI disorders. The effects of PF-3845 were mediated by endogenous CBs and non-CB lipophilic compounds via classical (CB1) and atypical CB receptors.

CONCLUSIONS & INFERENCES

These data expand our understanding of the ECS function and provide a novel framework for the development of future potential treatments of functional GI disorders.

Do newly built homes affect rhinitis in children? The ISAAC phase III study in Korea

BACKGROUND

As Korea has experienced rapid economic development, the lifestyles of Koreans have become more Westernized, in terms of urbanization and dietary habits. Also, the prevalences of allergic diseases, such as rhinitis, asthma, and dermatitis, have increased rapidly. This study aimed to identify the factors influencing the symptoms of rhinitis conditions, including rhinitis, allergic rhinitis, overlapped rhinitis, and overlapped allergic rhinitis, among Korean children aged 6-7 years.

METHODS

The study subjects were drawn from participants in the International Study of Asthma and Allergies in Childhood (ISAAC) study in 2010 and were aged 6-7 years. We analysed data for a total of 3804 children.

RESULTS

The prevalences of symptoms suggestive of rhinitis and allergic rhinitis in the previous 12 months were 43.4% and 22.1%, respectively. For overlapped rhinitis and overlapped allergic rhinitis, only 2.5% and 1.9% of the children had overlapping symptoms, having rhinitis with asthma and eczema simultaneously. Gender, a parental history of allergic disease, mould or dampness at home, and the risk factors for 'sick building syndrome' (SBS) were risk factors influencing rhinitis diseases. In particular, a history of moving to a newly built home in the child's infancy was strongly associated with symptoms of all the rhinitis diseases examined.

CONCLUSIONS

This study identified patterns of the prevalence of rhinitis conditions among Korean children that were similar to those reported in Western countries. We confirmed that a history of moving to a newly built home during infancy was associated with a considerable risk of rhinitis conditions.

Biopersistence of silver nanoparticles in tissues from Sprague-Dawley rats

Silver nanoparticles are known to be distributed in many tissues after oral or inhalation exposure. Thus, understanding the tissue clearance of such distributed nanoparticles is very important to understand the behavior of silver nanoparticles in vivo. For risk assessment purposes, easy clearance indicates a lower overall cumulative toxicity. Accordingly, to investigate the clearance of tissue silver concentrations following oral silver nanoparticle exposure, Sprague–Dawley rats were assigned to 3 groups: control, low dose (100 mg/kg body weight), and high dose (500 mg/kg body weight), and exposed to two different sizes of silver nanoparticles (average diameter 10 and 25 nm) over 28 days. Thereafter, the rats were allowed to recover for 4 months. Regardless of the silver nanoparticle size, the silver content in most tissues gradually decreased during the 4-month recovery period, indicating tissue clearance of the accumulated silver. The exceptions were the silver concentrations in the brain and testes, which did not clear well, even after the 4-month recovery period, indicating an obstruction in transporting the accumulated silver out of these tissues. Therefore, the results showed that the size of the silver nanoparticles did not affect their tissue distribution. Furthermore, biological barriers, such as the blood–brain barrier and blood-testis barrier, seemed to play an important role in the silver clearance from these tissues.

IgE-mediated anaphylaxis and allergic reactions to idursulfase in patients with Hunter syndrome

BACKGROUND

Enzyme replacement therapy (ERT) with recombinant human idursulfase is effective for the treatment of Hunter syndrome, mucopolysaccharidosis (MPS) type II. However, various adverse events can occur by the infusion of idursulfase. The purpose was to evaluate the occurrence of infusion-related allergic reactions, including anaphylaxis, to idursulfase in patients with MPS II receiving ERT and to elucidate its possible mechanism.

METHODS

A total of 34 patients with MPS II were enrolled to receive ERT with Elaprase(®) at a dose of 0.5 mg/kg intravenously once a week. Information regarding the symptoms, frequency, and timing of anaphylaxis during treatment was analyzed. Presence of anti-idursulfase IgE antibody was assessed by skin prick test (SPT) and enzyme-linked immunosorbent assay (ELISA). Western blotting was performed to confirm the reaction between idursulfase and specific IgE.

RESULTS

Three patients (8.8%) showed anaphylaxis by infusion of idursulfase. No deaths occurred during the study. Anti-idursulfase IgE antibody was detected by SPT and ELISA. Immunoblotting with patients' sera and Elaprase(®) showed a single band of specific IgE binding to the protein around 70 kD, and idursulfase did not display amino acid sequence homology to known allergens. SPT with idursulfase demonstrated positive results in all patients with anaphylaxis. However, we failed to reveal any risk factors for the development of infusion-related immediate-type allergic reactions.

CONCLUSIONS

Anaphylaxis related to infusion of idursulfase is mediated by anti-idursulfase IgE antibody, which might be produced by de novo synthesis. SPT is useful in predicting the occurrence of anti-idursulfase IgE-mediated anaphylaxis during infusion.

Diffusion MRI findings of cytomegalovirus-associated ventriculitis: a case report

Cytomegalovirus (CMV) ventriculoencephalitis is a rare but serious potential complication of CMV infection in immunocompromised patients. Characteristic diffusion-weighted imaging findings can be helpful for the diagnosis of CMV ventriculitis, as in this case report.

[Emergency operation and hypothermic therapy for Stanford type A acute aortic dissection in the state of coma]

We report of a 77-year-old woman who was admitted to our hospital in coma by emergency. A computed tomography scan revealed acute aortic dissection (Stanford type A). We established selective antegrade cerebral perfusion within 3 hours of the onset and then performed ascending aortic replacement. In the state of hypothermia (35 degrees C), the patient was weaned from cardiopulmonary bypass. The patient was kept hypothermic until the operation was completed. We kept mild hypothermia (34.5 degrees C) in intensive care unit (ICU) for 40 hours. The patient was extubated at 94 hours after the operation. The patient was discharged from the hospital on foot on postoperative day 21.

Netrin-1: a novel universal biomarker of human kidney injury

Currently available diagnostic markers representing kidney injury or function such as serum creatinine and blood urea nitrogen are insensitive and often increased late in the disease process. Netrin-1 protein, a laminin-related secreted molecule, is minimally or not expressed in tubular epithelial cells of normal kidneys. However, it is highly expressed in injured kidneys. Netrin-1 protein has been shown to be detected in urine from mice with acute kidney injury. The current study was carried out to evaluate whether netrin-1 is also induced in human acute kidney injury (AKI) and can serve as a urinary biomarker of the condition. We analyzed netrin-1 levels by sandwich enzyme-linked immunosorbent assay in urine samples from 10 healthy controls, 22 recipients of a renal allograft, 11 patients with ischemic AKI, 13 with AKI associated with sepsis, 9 with radiocontrast-induced AKI, and 8 with drug-induced AKI. Urinary netrin-1 levels normalized for urinary creatinine were significantly higher in all subject groups. The highest values were observed in patients with sepsis and in transplant patients immediately postoperatively. The level of NGAL was similarly increased in transplant patients. In conclusion, urinary netrin-1 levels are increased in patients with various forms of AKI/ATN and may serve as a universal biomarker for AKI.