Investigation on the skin penetration of synthetic amorphous silica (SAS) used in cosmetic products

Synthetic amorphous silica (SAS) is used as additive in a variety of industrial applications for many decades and has been approved to be used in food, food contact materials, pharmaceuticals, and cosmetics. Due its internal structure, SAS is considered as a nanomaterial, thus it is affected by a general safety discussion. Based on the production process, SAS for cosmetic application is a nanomaterial by the EU Recommendation, although it was not considered as such, because the solely size-dependent definitions of the term "nanomaterial" emerged in recent times first in Recommendation 2011/696/EU. Therefore, former physicochemical and toxicological evaluations of SAS were already performed on nanomaterials, however, without being addressed as such. Safety concerns can only emerge if two criteria, (toxicological) hazard and exposure towards the substance is fulfilled at the same time. In case of SAS, the Scientific Committee on Consumer Safety (SCCS) challenged provided data to be insufficient to draw a conclusion regarding the safety of SAS and thus, requested further investigations, in particular by exploring skin penetration of particulate SAS.Investigation of specific particulate substances in skin penetration tests is an analytical challenge. The number of available analytical techniques that are capable to detect nanomaterials in complex matrices, like receptor fluids from skin penetration testing, are limited and still emerging. In the new studies, a comprehensive set of analytical techniques were used to investigate the skin penetration potential of SAS. Particle-sensitive, element and particle-specific combinations of techniques and different sample preparation procedures, that respected the particulate nature of SAS, were used to detect SAS in receptor fluids directly. In addition, electron microscopic techniques were used to examine different layers of skin to detect adsorbed SAS.The combination of Asymmetric Flow Field-Flow Fractionation (AF4) in combination with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for examination of receptor fluids and Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy (SEM/EDX) for examination of skin itself, were identified as suitable techniques for the detection of SAS in skin penetration tests. Data from literature was used to compare the results of the studies with the outcome of other test systems (other particles, other techniques). Both, the test results, and literature evaluation led to the conclusion, that SAS does not penetrate skin. Based on this outcome and local and systemic dermal toxicity review of SAS, it can be concluded that dermal application of SAS in cosmetic formulations is negligible.

Considerations for and Guidance to Testing and Evaluating Migration/Release of Nanoparticles from Polymer Based Nanocomposites

The use of nanoadditives in food contact materials requires risk assessment to ensure consumers' safety. The evaluation of health risk is based on the combination of two elements: hazard and exposure. For nanomaterials (NM) used as additives in nanocomposites, the exposure is directly linked to the level of migration or release of the NM into the food. In principle, appropriate methods for experimental determination and theoretical estimation of migration are available but need diligent considerations to avoid erroneous conclusions from the measured data. We propose a comprehensive test scheme based on these methods, starting with characterization of the nanomaterial itself and when incorporated in the polymer. These data form the basis for making a decision whether migration of the NM can be excluded by migration theoretical considerations or if experimental migration testing and/or abrasion testing for mechanical release should be carried out. Guidance to and considerations for each of these steps and regarding the applicable methods are discussed. In conclusion, the results will provide a basis for risk assessment, either directly when exposure of consumers to the nanomaterials can be excluded or will be very low or, in the case of evidenced exposure, in combination with then needed toxicological data.

Investigation into the Potential Migration of Nanoparticles from Laponite-Polymer Nanocomposites

In this study, the migration potential of laponite, a small synthetic nanoclay, from nanocomposites into foods was investigated. First, a laponite/ethylene vinyl acetate (EVA) masterbatch was compounded several times and then extruded into thin low-density polyethylene (LDPE) based films. This way, intercalation and partial exfoliation of the smallest type of clay was achieved. Migration of laponite was investigated using Asymmetric Flow Field-Flow Fractionation (AF4) with Multi-Angle Laser Light Scattering (MALLS) detection. A surfactant solution in which laponite dispersion remained stable during migration test conditions was used as alternative food simulant. Sample films with different loadings of laponite were stored for 10 days at 60 °C. No migration of laponite was found at a limit of detection of 22 µg laponite per Kg food. It can be concluded that laponite (representing the worst case for any larger structured type of clay) does not migrate into food once it is incorporated into a polymer matrix.

Migration of nanoparticles from plastic packaging materials containing carbon black into foodstuffs

Carbon black was investigated to assess and quantify the possibility that nanoparticles might migrate out of plastic materials used in the food packaging industry. Two types of carbon black were incorporated in low-density polyethylene (LDPE) and polystyrene (PS) at 2.5% and 5.0% loading (w/w), and then subjected to migration studies. The samples were exposed to different food simulants according to European Union Plastics Regulation 10/2011, simulating long-term storage with aqueous and fatty foodstuffs. Asymmetric flow field-flow fractionation (AF4) coupled to a multi-angle laser light-scattering (MALLS) detector was used to separate, characterise and quantify the potential release of nanoparticles. The AF4 method was successful in differentiating carbon black from other matrix components, such as extracted polymer chains, in the migration solution. At a detection limit of 12 µg kg⁻¹, carbon black did not migrate from the packaging material into food simulants. The experimental findings are in agreement with theoretical considerations based on migration modelling. From both the experimental findings and theoretical considerations, it can be concluded that carbon black does not migrate into food once it is incorporated into a plastics food contact material.

Ambulatory oxygen improves the effectiveness of pulmonary rehabilitation in selected patients with chronic obstructive pulmonary disease

The effect of ambulatory oxygen use during pulmonary rehabilitation (PR) has not yet been clearly established, but many studies have shown benefit from oxygen acutely. Two small studies to date demonstrated no clear benefit when oxygen was used in patients who desaturated on exertion during a PR programme. One study showed the benefit of using oxygen during PR in patients who were normoxic at rest and desaturated to a minimum of 88% on exertion. We conducted a single-blind, randomised controlled trial comparing PR undertaken either with or without ambulatory oxygen, in those with demonstrable benefit from oxygen at baseline. Subjects from three PR services were recruited who, during baseline assessment, desaturated by more than 4% and to less than 90% on exertion, and walked 10% or more further with ambulatory oxygen on endurance shuttle walk test. Patients were randomised to either room air or oxygen via portable cylinder, titrated to optimise pulse oxygen saturation but up to a maximum flow rate of 6 L/min. All patients then completed a twice weekly, 6- to 7-week PR programme. Data were analysed as per protocol. Totally 51 patients completed the study. At the end of PR, both groups improved with PR, with patients in the oxygen group demonstrating a highly statistically significantly greater mean improvement in endurance walking distance than the controls, 490 m (95% confidence interval 228–750; p ≤ 0.001), as well as clinically, although not statistically, significant changes in quality of life. The use of ambulatory oxygen during a 6- to 7-week PR programme greatly improved endurance walking distance in patients who desaturated on exertion with a positive acute response to ambulatory oxygen at baseline.

Physiotherapy for adult patients with critical illness: recommendations of the European Respiratory Society and European Society of Intensive Care Medicine Task Force on Physiotherapy for Critically Ill Patients

The Task Force reviewed and discussed the available literature on the effectiveness of physiotherapy for acute and chronic critically ill adult patients. Evidence from randomized controlled trials or meta-analyses was limited and most of the recommendations were level C (evidence from uncontrolled or nonrandomized trials, or from observational studies) and D (expert opinion). However, the following evidence-based targets for physiotherapy were identified: deconditioning, impaired airway clearance, atelectasis, intubation avoidance, and weaning failure. Discrepancies and lack of data on the efficacy of physiotherapy in clinical trials support the need to identify guidelines for physiotherapy assessments, in particular to identify patient characteristics that enable treatments to be prescribed and modified on an individual basis. There is a need to standardize pathways for clinical decision-making and education, to define the professional profile of physiotherapists, and increase the awareness of the benefits of prevention and treatment of immobility and deconditioning for critically ill adult patients.

An analysis of paper-based sources of information on complementary therapies

This study involved an investigation into the availability of paper-based publications containing information on complementary therapies (CTs) within a single cancer centre in the North West. The publications were collected during a 1-week period in July 2003 from the four most likely locations in the site that a patient would visit, to ensure that the research related to data that was readily available. An evaluation grid was developed, and the quantity and quality of the data presented about CTs were analysed. A total of 80 publications were collected. Forty-five (56.3%) related to breast cancer specifically, of which only six (20.7%) made reference to CTs. Thirty-five (43.8%) related to cancer in general, of which only 16 (45.7%) made reference to CTs. The type of information relating to CTs was of very limited value to assist in reaching any decisions as to their use. As a result, it was recommended that the healthcare service prepare and publish a leaflet, specifically relating to the use of CTs in the treatment of cancer, to be freely available within the site for the use of its breast cancer patients.

Domains, constructs and the development of the breathing problems questionnaire

Health-related quality of life (QoL) questionnaires are commonly developed as content valid instruments with conventionally defined domain subscales. We contrasted content valid domain subscales with construct valid construct subscales and developed a 13-domain QoL questionnaire, the Breathing Problems Questionnaire (BPQ), for patients with chronic bronchitis. In a series of studies, we examined the constructs relevant to COPD patients' experience of health. First, we provided psychometric evidence that items in the BPQ form two distinct groups: functional problems and negative evaluations. Second, we showed that problems were significantly more correlated with morbidity whereas negative evaluations were significantly more correlated with neuroticism. Third, we showed that negative evaluations correlated with neuroticism whereas positive evaluations (measured by the Satisfaction with Illness Scale) correlated with extraversion. Patients are more likely to make positive evaluations of their illness when they recognize that they are seriously ill. Most of the BPQ domains are subcategories of the construct of problems: both domains and construct classifications provide useful information.

Randomised controlled trial of nasal ventilation in acute ventilatory failure due to chronic obstructive airways disease

Acute exacerbations of chronic obstructive airways disease (COAD) are a common cause of admission to hospital, and have a high mortality. Nasal intermittent positive pressure ventilation (NIPPV) has been used successfully in patients with respiratory failure due to neuromuscular and skeletal disorders, but the outcome of treatment in patients with COAD is less well known. We carried out a prospective randomised controlled trial of conventional treatment versus conventional treatment plus NIPPV, in 60 patients with acute ventilatory failure due to exacerbations of COAD. For the NIPPV group there was a rise in pH, compared with a fall in the controls (mean difference of change between the groups 0.046 [95% CI 0.06-0.02, p < 0.001]), and a larger fall in PaCO2 (mean difference in change between the groups 1.2 kPa [95% CI 0.45 to 2.03, p < 0.01]). Median visual analogue scores over the first 3 days of admission showed less breathlessness in the NIPPV group (2.3 cm [range 0.1-5.5]) than in the control group (4.5 cm [range 0.9-8.8]) (p < 0.025). Survival rates at 30 days were compared for intention-to-treat and efficacy populations. In the efficacy mortality comparison, mortality in the NIPPV group was reduced: 1/26 vs 9/30 (relative risk = 0.13, CI = 0.02-0.95, p = 0.014). This effect was less in the intention-to-treat analysis: 3/30 vs 9/30 (relative risk = 0.33, CI = 0.10-1.11, p = 0.106). In patients with acute ventilatory failure due to COAD who received NIPPV there was a significant rise in pH, a reduction in PaCO2 and breathlessness, and reduced mortality.

Short term effect of oxygen on renal haemodynamics in patients with hypoxaemic chronic obstructive airways disease

BACKGROUND

Oxygen therapy is effective in the prevention and treatment of oedematous exacerbations of cor pulmonale. As renal blood flow is reduced in cor pulmonale a study was designed to investigate whether one of the beneficial effects of oxygen was to increase renal blood flow. The effect of oxygen therapy on renal haemodynamics measured noninvasively was examined in patients with chronic obstructive airways disease and previous episodes of oedema.

METHODS

Renal blood flow waveforms were recorded in a single vessel by colour flow Doppler ultrasound in nine hypoxaemic patients (PaO2) (arterial oxygen tension < 8 kPa while they were breathing air) with chronic obstructive airways disease and previous oedema and eight age matched normoxaemic volunteers (arterial oxygen saturation (SaO2) 97% or more when breathing air) while they were breathing air and oxygen. SaO2 and transcutaneous PaO2 (TcPO2) and PaCO2 (TcPCO2) were monitored. Five renal velocity profile recordings were made from the same segmental vessel with the patient breathing room air for one hour followed by oxygen titrated to achieve an oxygen saturation of 95% or more without a rise in TcPCO2 for 15 minutes. Control subjects breathed 35% oxygen.

RESULTS

No significant change in the pulsatility index (a measure of distal vascular resistance) or mean height of the waveform (Tamx, a measure of renal blood flow) occurred in the control subjects while they were breathing air or oxygen. The pulsatility index of the patients with chronic obstructive airways disease was significantly greater than that in the control subjects breathing air (1.44 (SD 0.28) v 1.03 (0.14). Breathing oxygen was associated with an increase in TcPO2 in the patients (from 6.9 (1.9) to 11.5 (0.7) kPa), a fall in pulsatility index (from 1.44 (0.28) to 1.26 (0.14) and an increase in Tamx (from 0.187 (0.055) to 0.234 (0.087) m/s).

CONCLUSIONS

The results suggest that renal vascular resistance is increased in patients with chronic obstructive airways disease and hypoxaemia and that short term oxygen therapy reduces renal vascular resistance and increases blood flow. Some of the benefits of oxygen therapy in cor pulmonale may be due to improvements in renal haemodynamics.

Nasal intermittent positive pressure ventilation in the treatment of respiratory failure in obstructive sleep apnoea

Severe respiratory failure in a patient with obstructive sleep apnoea was treated successfully with nasal intermittent positive pressure ventilation.