Pollution by particulates has been consistently associated with increased cardiovascular morbidity and mortality. However, the mechanisms responsible for these effects are not well-elucidated.
To ...assess to what extent and how rapidly inhaled pollutant particles pass into the systemic circulation, we measured, in 5 healthy volunteers, the distribution of radioactivity after the inhalation of "Technegas," an aerosol consisting mainly of ultrafine (99m)Technetium-labeled carbon particles (<100 nm). Radioactivity was detected in blood already at 1 minute, reached a maximum between 10 and 20 minutes, and remained at this level up to 60 minutes. Thin layer chromatography of blood showed that in addition to a species corresponding to oxidized (99m)Tc, ie, pertechnetate, there was also a species corresponding to particle-bound (99m)Tc. Gamma camera images showed substantial radioactivity over the liver and other areas of the body.
We conclude that inhaled (99m)Tc-labeled ultrafine carbon particles pass rapidly into the systemic circulation, and this process could account for the well-established, but poorly understood, extrapulmonary effects of air pollution.
The current authors evaluated whether a system of co-cultures of relevant cells (pneumocytes (A549), macrophages (THP-1), mast cells (HMC-1) and endothelial cells (EAHY926)) would mimic the responses ...to particles with a 50% cut-off aerodynamic diameter of 10 microm (PM(10)) previously reported in vivo. The role of mast cells was considered of special interest. Single cultures, bicultures (A549 + HMC-1 in a 10:1 ratio; THP-1 + HMC-1 in a 2:1 ratio) and tricultures (A549 + THP-1 + HMC-1 in a 10:2:1 ratio) were exposed to urban PM(10) (24 h at 0, 10, 30 or 100 microg x cm(-2)). Additionally, EAHY926 cells were introduced in inserts above the tricultures. The released cytokines were evaluated with a fluorescence-activated cell sorter array system. THP-1 + HMC-1 bicultures and the tricultures released more granulocyte colony-stimulating factor (G-CSF), macrophage inflammatory protein (MIP)-1beta, interleukin (IL)-1beta, IL-8, IL-6, tumour necrosis factor-alpha and MIP-1alpha in response to PM(10) than the sum of the single cultures. Tricultures with EAHY926 released more G-CSF, MIP-1alpha, IL-8 and MIP-1beta than the EAHY926 single culture. The bicultures, tricultures and tricultures with EAHY926 provide results that are consistent with the local and systemic effects previously described for particulate matter effects, i.e. inflammation, endothelial dysfunction and bone marrow cell mobilisation. Mast cells seem to play a significant role in the co-culture responses.
Highlights • At long term exposures AgNPs are more toxic than the equal dose of ionic silver. • AgNP10 are more prone to form large aggregates than AgNP20. • AgNP20 induces cell cycle arrest at G0/G1 ...phase and apoptosis. • AgNP10 induced necrosis but no interference in cycle dynamics. • AgNPs size influences the mechanisms of cell death. • Part of AgNP toxicity is by the NPs itself or by NPs-deliver of the Ag+ into cells
The SCCS has concluded that the evidence, both provided in the submission and that available in scientific literature, is inadequate and insufficient to allow drawing any firm conclusion either for ...or against the safety of any of the individual SAS material, or any of the SAS categories that are intended for use in cosmetic products.
As the SCCS has not been able to conclude on the safety of the synthetic amorphous silica (SAS) materials included in the current submission, the Applicant is advised to follow the SCCS Guidance on Risk Assessment of Nanomaterials (SCCS/1484/12).
A brief summary is provided to enable/facilitate future evaluation of the SAS materials in cosmetic products.
•The SCCS has concluded that the evidence is inadequate and insufficient to allow drawing any firm conclusion.•The Applicant is advised to follow the SCCS Guidance on Risk Assessment of Nanomaterials (SCCS/1484/12).•A summary is provided to enable future evaluation of the synthetic amorphous silica materials in cosmetic products.
The mechanisms of particulate pollution-related cardiovascular morbidity and mortality are not well understood. We studied the passage of radioactively labeled ultrafine particles after their ...intratracheal instillation. Hamsters received a single intratracheal instillation of 100 microg albumin nanocolloid particles (nominal diameter < or = 80 nm) labeled with 100 microCi technetium-99m and were killed after 5, 15, 30, and 60 min. In blood, radioactivity, expressed as percentage of total body radioactivity per gram blood, amounted to 2.88 +/- 0.80%, 1.30 +/- 0.17%, 1.52 +/- 0.46%, and 0.21 +/- 0.06% at 5, 15, 30, and 60 min, respectively. Thin-layer chromatography showed only one peak of radioactivity corresponding to unaltered (99m)Tc-albumin nanocolloid. In the liver, radioactivity, expressed as percentage of total radioactivity per organ, amounted to 0.10 +/- 0.07%, 0.23 +/- 0.06%, 1.24 +/- 0.27%, and 0.06 +/- 0.02% at 5, 15, 30, and 60 min, respectively. Lower values were observed in the heart, spleen, kidneys, and brain. Dose dependence was assessed at 30 min following instillation of 10 microg and 1 microg (99m)Tc-albumin per animal (n = 3 at each dose), and values of the same relative magnitudes as after instillation of 100 microg were obtained. We conclude that a significant fraction of (99m)Tc-albumin, taken as a model of ultrafine particles, rapidly diffuses from the lungs into the systemic circulation.
Background
Chronic rhinosinusitis (CRS) is a frequent condition that is treated by functional endoscopic sinus surgery (FESS) when medical treatment fails. Endogenous as well as exogenous factors may ...be responsible for persisting symptoms after FESS. The role of occupational exposures on success of FESS has never been investigated.
Methods
In this case–control study, we tested the hypothesis that the outcome of FESS procedures is related to exposures at work. Questionnaires were sent to 890 patients who had undergone one or more FESS procedures and to 182 controls. Three independent experts assessed blindly the reported work exposures to inhaled agents. The relationship between exposure and the number of FESS procedures was analyzed.
Results
Relevant occupational exposure was reported by 25% of all responding patients undergoing FESS (n = 467) and 12% of controls (n = 69). The prevalence of occupational exposures increased linearly with the number of FESS procedures from 21% in those who had one FESS to 44% in those who had four or more FESS (χ2 = 12.74, P < 0.001). Logistic regression analysis with adjustments for potential confounders, including smoking, atopy, and asthma, confirmed that the odds ratio (OR) for reporting occupational exposures was significantly higher in those needing more than one FESS (OR = 1.64) or more than two FESS (OR = 1.97). These results were mainly driven by exposure to low molecular weight agents.
Conclusion
Exposure at work appears to be a risk factor for the occurrence of CRS and for its recurrence or persistence, as evidenced by the need for revision surgery.
Summary
Background
Little is known about the impact of engineered nanoparticles (ENPs) on skin sensitization caused by chemicals.
Objectives
We determined the ability of different ENPs (TiO2, Ag and ...SiO2) and aged paint particles containing ENPs to modulate dermal sensitization by a known potent dermal sensitizer.
Methods
The fur of BALB/c mice in the area around the ears was cut with scissors 1 day prior to topical exposure to ENPs (0·4, 4 or 40 mg mL−1), paint particles containing ENPs (4 mg mL−1) or vehicle (day 0). On days 1, 2 and 3, the mice received dermal applications on the back of both ears of 2,4‐dinitrochlorobenzene (DNCB) or vehicle. The stimulation index (SI) was calculated on day 6.
Results
Topical exposure to TiO2, Ag or SiO2 ENPs, or aged paint particles followed by vehicle treatment as a control, did not influence the SI. When 4 mg mL−1 TiO2 ENPs were applied prior to DNCB sensitization, we found an increased SI compared with vehicle‐exposed mice prior to DNCB sensitization. Furthermore, an increased titanium concentration was found in the draining lymph node cells of this group. Topical exposure to Ag or SiO2 ENPs or aged paint particles prior to DNCB sensitization did not influence the SI.
Conclusions
We have demonstrated that topical exposure to TiO2 ENPs increases chemical‐induced dermal sensitization.
What's already known about this topic?
Nanoparticles can exert immunotoxic effects.
TiO2 nanoparticles modulate dermal sensitization with dinitrochlorobenzene after subcutaneous injection (worst‐case scenario).
What does this study add?
TiO2 nanoparticles modulate chemical‐induced dermal sensitization after topical exposure.
Nanoparticles incorporated in a paint matrix have no immunomodulatory effects on dermal sensitization after topical exposure.
Abstract Objectives Dental personnel are more at risk to develop asthmatic disease, but the exact reason is so far unknown. During abrasive procedures, dental personnel are exposed to nano-sized dust ...particles released from dental composite. The aim of this study was to investigate whether respirable composite dust may also release monomers. Methods Respirable (<5 μm) composite dust was collected and the release of methacrylate monomers and Bisphenol A (BPA) in water and ethanol was evaluated by liquid chromatography/mass spectroscopy (LC–MS/MS). The dust was ultra-morphologically and chemically analyzed by transmission electron microscopy and energy-dispersive X-ray spectroscopy (TEM-EDS). Results LC–MS/MS analysis revealed that, irrespective of the type of composite, the respirable fraction of composite dust may release relatively high concentrations of unpolymerized methacrylate monomers, both in water and ethanol. Higher release was observed in ethanol. The endocrine disruptor BPA also emanated from the composite dust particles. TEM showed that most particles were nano-sized, although particle size ranged between 6 nm and 5 μm with a mode value between 12 and 39 nm. Most particles consisted of several filler particles in resin matrix, although single nano-filler particles could also be observed. Elemental analysis by TEM-EDS proved that the particles collected on the filters originated from the dental composites. Conclusion Theoretically, composite dust may function as a vehicle to transport monomers deeply into the respiratory system. The results of this study may shed another light on the increasing incidence of respiratory disease among dental personnel, and more care should be taken to prevent inhalation of composite dust. Clinical significance Special care should be taken to prevent inhalation of composite dust, as the dust particles may release methacrylate monomers.
Background: Numerous studies have shown a strong association between daily mortality and small particulate with a diameter of <10 µm (PM10) air pollution, but the effects of season have not always ...been well characterised. Aim: To study the shape of the association between short-term mortality and PM10 across seasons and quintiles of outdoor temperature. Design, setting and participants: Daily data on mortality (n = 354 357), outdoor temperature and PM10 in Flanders, Belgium, from January 1997 to December 2003, were analysed across warm versus cold periods of the year (April–September v October–March), with seasons and quintiles of outdoor temperature as possible effect modifiers. Results: There was a significant (p<0.001) interaction between PM10 and period of the year in relation to mortality. To allow for non-linearity, daily mean PM10 concentrations were categorised into quartiles. Season-specific PM10 quartiles showed a strong and steep linear association between mortality and PM10 in summer and a less linear association in spring and autumn, whereas in winter the association was less strong and mortality was only increased in the highest PM10 quartile. The effect sizes expressed as the percentage increase in mortality on days in the highest season-specific PM10 quartile versus the lowest season-specific PM10 quartile were 7.8% (95% CI 6.1 to 9.6) in summer, 6.3% (4.7 to 7.8) in spring, 2.2% (0.58 to 3.8) in autumn and 1.4% (0.06 to 2.9) in winter. An analysis by quintiles of temperature confirmed these effect sizes. Conclusion: The short-term effect of particulate air pollution on mortality strongly depends on outdoor temperature, even in a temperate climate.
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