Squalene Depletion in Skin Following Human Exposure to Ozone under Controlled Chamber Conditions

A major component of human skin oil is squalene, a highly unsaturated hydrocarbon that protects the skin from atmospheric oxidants. Skin oil, and thus squalene, is continuously replenished on the skin surface. Squalene is also quickly consumed through reactions with ozone and other oxidants. This study examined the extent of squalene depletion in the skin oils of the forearm of human volunteers after exposure to ozone in a climate chamber. Temperature, relative humidity (RH), skin coverage by clothing, and participants' age were varied in a controlled manner. Concentrations of squalene were determined in skin wipe samples collected before and after ozone exposure. Exposures to ozone resulted in statistically significant decreases in post-exposure squalene concentrations compared to pre-exposure squalene concentrations in the skin wipes when squalene concentrations were normalized by concentrations of co-occurring cholesterol but not by co-occurring pyroglutamic acid (PGA). The rate of squalene loss due to ozonolysis was lower than its replenishment on the skin surface. Within the ranges examined, temperature and RH did not significantly affect the difference between normalized squalene levels in post-samples versus pre-samples. Although not statistically significant, skin coverage and age of the volunteers (three young adults, three seniors, and three teenagers) did appear to impact squalene depletion on the skin surfaces.

The fate of organic peroxides indoors: quantifying humidity-dependent uptake on naturally soiled indoor window glass

Humidity plays an important role in the surface removal and concentrations of indoor pollutants such as ozone; however, the indoor surface dynamics and chemistry of organic peroxides is largely unknown. Organic hydroperoxides (ROOHs) are known to participate in the multiphase chemistry of outdoor aerosols and clouds, suggesting that reactive uptake in condensed grime on indoor surfaces is plausible, particularly in humid homes. Here, the effect of relative humidity (RH) on the deposition velocity (v_d) and reaction probability (γ) of a model ROOH to naturally soiled indoor glass surfaces was investigated; specifically, by using authentic isoprene hydroxy hydroperoxide (1,2-ISOPOOH) as the model compound. Glass was soiled in 3 local homes for 1+ years and characterized. The removal of ISOPOOH by soiled and clean glass was measured under 5-6%, 56-58%, and 83-84% RH conditions using a novel flow reactor designed for indoor surfaces coupled to an iodide chemical ionization high-resolution time-of-flight mass spectrometer (I-HR-TOF-CIMS). The v_d and γ increased with increasing RH, ranging from 0.001-0.059 cm s^-1 and 0.4-4.6 (×10^-6), respectively, on soiled glass surfaces. The v_d and γ ranged from only 0.001-0.016 cm s^-1 and 0.1-0.8 (×10^-6), respectively, across RH conditions on clean glass, demonstrating a greater RH effect on soiled materials than clean. Loss rates calculated under humid conditions to soiled glass (∼1-6 h^-1) were competitive in scale with ventilation rates in typical residences, indicating the importance of surface uptake for indoor ROOH concentrations. This work provides parameters for predictive modeling of indoor ROOHs. To our knowledge, these are the first direct measurements of the v_d of an ROOH to naturally soiled indoor surfaces.

Indoor monoterpene emission rates from commercial cannabis cultivation facilities in Colorado

In 2019, an air emissions field sampling study was conducted by the Colorado Department of Public Health and Environment's Air Pollution Control Division (APCD) at four commercial cannabis cultivation facilities. Measurements of ambient biogenic volatile organic compounds (VOC) concentrations were collected from various growing stages of cannabis (vegetative and flowering) and during post-harvest activities (drying and trimming). These data were then used to determine room-specific biogenic VOC emission rates for three of the facilities from the vegetative stage of the life cycle through post-harvest activities. This study shows that the magnitude of biogenic VOC emissions within a cannabis cultivation facility varies widely with the highest emission rates of up to 7.18E-1 kg/hr found during mechanical trimming and up to 2.33E-1 kg/hr in the drying rooms. These were up to an order of magnitude higher than emission rates found in the cultivation rooms. For example, Facility A vegetative room had an emissions rate of 1.46E-2 kg/hr. Normalized by the amount of biomass present, the drying rooms had the highest VOC emissions rates, with a maximum rate of 1.6E-3 kg/hr/kg biomass. The flowering room rates were found to be up to 3.25E-4 kg/hr/kg biomass and drying rooms up to 1.16E-3 kg/hr/kg biomass. When normalized by plant count, emission rates in the flower rooms ranged from 8.11E-6 to 3.62E-4 kg/hr/plant. The dominant monoterpenes from sampling were β-myrcene, terpinolene, and D-limonene. These data suggest that the variability in emission rates across cannabis production will create a challenge in establishing a generalized emission factor for all facilities. Across the industry, cannabis cultivation conditions and strategies can vary widely impacting the amount and type of VOC emissions. Minimizing uncertainties for VOC emission from cannabis facilities requires site-specific information on air exchange rates, plant counts, cannabis strains, biomass, and if hand or mechanical processing is used.Implications: This study found that the magnitude of biogenic VOC emissions within a cannabis cultivation varies widely throughout rooms found in the facility, with the highest emissions found during post-harvest activities (i.e. trimming) and the lowest rates in the vegetative room. These data suggest that the large emission sources of VOCs are found post-harvest and emission inventories based solely on cultivation emissions will underestimate total biogenic VOC emissions from indoor cannabis cultivation facilities. The dominant measured terpenes throughout all facilities from cultivation to post harvest were: β-myrcene, terpinolene, and D-limonene.

Analytical method interferences for perfluoropentanoic acid (PFPeA) and perfluorobutanoic acid (PFBA) in biological and environmental samples

While high-resolution MS (HRMS) can be used for identification and quantification of novel per- and polyfluorinated alkyl substances (PFAS), low-resolution MS/MS is the more commonly used and affordable approach for routine PFAS monitoring. Of note, perfluoropentanoic acid (PFPeA) and perfluorobutanoic acid (PFBA), two of the smaller carboxylic acid containing-PFAS, have only one major MS/MS transition, preventing the use of qualitative transitions for verification on low-resolution instrumentation. Recently our lab has observed widespread chemical interference in the quantitative ion channel for PFPeA (263 → 219) and PFBA (213 → 169) in numerous matrices. PFPeA interference was investigated using HRMS and putatively assigned as a diprotic unsaturated fatty acid (263.1288 Da) in shellfish and a separate interferent (13C isotope of 262.1087 Da) in hot cocoa, which had been previously described by the FDA. PFBA interference caused by saturated oxo-fatty acids, previously demonstrated in tissue, was also observed in liquid condensate from a residential air conditioning unit. Therefore, in support of PFAS analysis on low-resolution instrumentation, authors recommend several adjustments to analytical methods including altering liquid chromatography (LC) conditions as well as using matched internal standards to investigate and expressly confirm PFBA and PFPeA detections in both biological and environmental samples.

The influence of personal care products on ozone-skin surface chemistry

Personal care products are increasingly being marketed to protect skin from the potentially harmful effects of air pollution. Here, we experimentally measure ozone deposition rates to skin and the generation rates and yields of oxidized products from bare skin and skin coated with various lotion formulations. Lotions reduced the ozone flux to the skin surface by 12% to 25%; this may be due to dilution of reactive skin lipids with inert lotion compounds or by reducing ozone diffusivity within the resulting mixture. The yields of volatile squalene oxidation products were 25% to 70% lower for a commercial sunscreen and for a base lotion with an added polymer or with antioxidants. Lower yields are likely due to competitive reactions of ozone with lotion ingredients including some ingredients that are not intended to be ozone sinks. The dynamics of the emissions of squalene ozonation product 6 methyl-2-heptenone (6MHO) suggest that lotions can dramatically reduce the solubility of products in the skin film. While some lotions appear to reduce the rate of oxidation of squalene by ozone, this evidence does not yet demonstrate that the lotions reduce the impact of air pollution on skin health.

Understanding Ozone Transport and Deposition within Indoor Surface Boundary Layers

Ozone-initiated oxidation reactions on indoor surfaces meaningfully alter the chemical composition of indoor air and human exposure to air toxins. Ozone mass transport within the indoor surface boundary layer plays a key role in ozone-surface reaction kinetics. However, limited information is available on detailed ozone transport dynamics near realistic, irregular indoor surfaces. This paper presents a research framework to study the underlying mechanisms of ozone reactions with realistic indoor surfaces based on microscope scanning of surface material and detailed Computational Fluid Dynamics (CFD) simulation. The study results show that indoor surface topography can meaningfully affect ozone mass transport within a surface boundary layer, thereby modulating near-surface ozone concentration gradient and surface uptake. The results also reveal that the effective indoor surface area available for ozone reaction varies with indoor air speed and turbulent air mixing within the boundary layer. The detailed dynamic behaviors of ozone reactions with realistic indoor surfaces provide insights into the implications of pollutant-surface interactions on indoor chemistry and air quality.

A national survey of window-opening behavior in United States homes

Air exchange is among the most important building parameters influencing indoor air quality and energy use. Over 18-month period we surveyed over 3800 individuals to generate a contemporary, nationwide measure of window- and door-opening behavior. We also identified influences of demographics, climate, and region. For the entire survey, including all seasons and geographic regions, 43.9% of respondents said that at least one window was open the day prior to taking the survey. Greater window-opening frequency was associated with having a lower income, living in attached homes or apartments, renting, lack of air conditioning, or being Asian or Hispanic. People living in the west and north open windows considerably more frequently and longer than those in the southeastern US. Window-opening frequency and duration increases with outdoor temperature until a maximum occurs at 18-21°C. At temperatures greater than this, window frequency decreases. The pattern roughly holds, by region, with the peak occurring at a lower temperature in the NW (12°C), and a higher temperature in the SW and SE. The frequency of door opening is roughly half that of window opening with similar, but not identical, demographic, regional, and climate associations.

Per- and Polyfluoroalkyl Substances (PFASs) in Airborne Particulate Matter (PM2.0) Emitted During Floor Waxing: A Pilot Study

Per- and polyfluoroalkyl substances (PFASs), with their water- and heat-resistant properties, have been widely used in industrial and consumer products, including floor waxes. Adverse health effects are associated with PFAS exposures (e.g., increased risk of cancer and immunotoxicity); however, exposures resulting from the use of PFAS-containing products are poorly understood. This study examines PFAS emissions during professional floor stripping/waxing and their potential for occupational exposures. We measured PFASs in dust and airborne particulate matter (PM_2.0, aerodynamic diameter ≤ 2.0 μm) before, during, and after floor stripping/waxing activities in three rooms in a university building. PM_2.0 samples were analyzed for 34 targeted PFASs by ultra-high performance liquid chromatography coupled to electrospray ionization triple quadrupole mass spectrometer (UHPLC/ESI-MS/MS). In total, ten PFASs were detected in PM_2.0 collected during floor waxing. Five were consistently higher during floor stripping/waxing compared to before (two with 95% confidence interval): perfluoro-2-methoxyacetic acid, perfluorobutanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, and perfluorooctane sulfonic acid. For these five, estimated exposures during floor stripping were 80.6, 320.5, 83.8, 29.6, and 157.7 pg m^-3 per hour of floor stripping, respectively, one order of magnitude greater than typical residential indoor and two orders of magnitude greater than ambient outdoor concentrations. Estimated emission rates were 3.0, 9.6, 3.4, 1.5, and 6.5 ng h^-1m^-2, respectively (34.6% uncertainty). Inhalation occupational exposures were in the range of 9.42-23.2 pg per kg body weight per hour of floor stripping across the five PFASs.

Effect of Ozone, Clothing, Temperature, and Humidity on the Total OH Reactivity Emitted from Humans

People influence indoor air chemistry through their chemical emissions via breath and skin. Previous studies showed that direct measurement of total OH reactivity of human emissions matched that calculated from parallel measurements of volatile organic compounds (VOCs) from breath, skin, and the whole body. In this study, we determined, with direct measurements from two independent groups of four adult volunteers, the effect of indoor temperature and humidity, clothing coverage (amount of exposed skin), and indoor ozone concentration on the total OH reactivity of gaseous human emissions. The results show that the measured concentrations of VOCs and ammonia adequately account for the measured total OH reactivity. The total OH reactivity of human emissions was primarily affected by ozone reactions with organic skin-oil constituents and increased with exposed skin surface, higher temperature, and higher humidity. Humans emitted a comparable total mixing ratio of VOCs and ammonia at elevated temperature-low humidity and elevated temperature-high humidity, with relatively low diversity in chemical classes. In contrast, the total OH reactivity increased with higher temperature and higher humidity, with a larger diversity in chemical classes compared to the total mixing ratio. Ozone present, carbonyl compounds were the dominant reactive compounds in all of the reported conditions.

Spatial distributions of ozonolysis products from human surfaces in ventilated rooms

Ozone has adverse effects on human health. Skin oil on the human surface acts as an ozone sink indoors, producing oxidation products that can cause skin and respiratory irritations. Concentrations of ozone and oxidation products near human surfaces, including the breathing zone, can be modulated by indoor ventilation modes and human surface conditions. The objective of this study is to examine concentrations and spatial heterogeneity of ozone and ozonolysis products under representative ranges of indoor ventilation, clothing, and breathing conditions. Using computational fluid dynamics (CFD) simulation in conjunction with a chemical kinetic model, details of ozone reactions with the human surface and subsequent chemical reactions are examined. The results show that primary ozonolysis products are concentrated near the soiled clothing, while the secondary products are relatively well distributed throughout the room. Increasing indoor air mixing enhances the ozone deposition to the human surface, thereby resulting in higher emission rates of oxidation products in the room. Soiled clothing consumes more ozone than clean clothing and accordingly produces ~ 65% more primary products and ~15% more secondary products. The results also reveal that unsaturated hydrocarbons from the human breath, such as isoprene, contribute to only ~0.5% of ozone removal compared to ozone deposition to the human surface.

The Indoor Chemical Human Emissions and Reactivity (ICHEAR) project: Overview of experimental methodology and preliminary results

With the gradual reduction of emissions from building products, emissions from human occupants become more dominant indoors. The impact of human emissions on indoor air quality is inadequately understood. The aim of the Indoor Chemical Human Emissions and Reactivity (ICHEAR) project was to examine the impact on indoor air chemistry of whole-body, exhaled, and dermally emitted human bioeffluents under different conditions comprising human factors (t-shirts/shorts vs long-sleeve shirts/pants; age: teenagers, young adults, and seniors) and a variety of environmental factors (moderate vs high air temperature; low vs high relative humidity; presence vs absence of ozone). A series of human subject experiments were performed in a well-controlled stainless steel climate chamber. State-of-the-art measurement technologies were used to quantify the volatile organic compounds emitted by humans and their total OH reactivity; ammonia, nanoparticle, fluorescent biological aerosol particle (FBAP), and microbial emissions; and skin surface chemistry. This paper presents the design of the project, its methodologies, and preliminary results, comparing identical measurements performed with five groups, each composed of 4 volunteers (2 males and 2 females). The volunteers wore identical laundered new clothes and were asked to use the same set of fragrance-free personal care products. They occupied the ozone-free (<2 ppb) chamber for 3 hours (morning) and then left for a 10-min lunch break. Ozone (target concentration in occupied chamber ~35 ppb) was introduced 10 minutes after the volunteers returned to the chamber, and the measurements continued for another 2.5 hours. Under a given ozone condition, relatively small differences were observed in the steady-state concentrations of geranyl acetone, 6MHO, and 4OPA between the five groups. Larger variability was observed for acetone and isoprene. The absence or presence of ozone significantly influenced the steady-state concentrations of acetone, geranyl acetone, 6MHO, and 4OPA. Results of replicate experiments demonstrate the robustness of the experiments. Higher repeatability was achieved for dermally emitted compounds and their reaction products than for constituents of exhaled breath.

Fenfluramine HCl (Fintepla® ) provides long-term clinically meaningful reduction in seizure frequency: Analysis of an ongoing open-label extension study

OBJECTIVE

Fenfluramine has been shown to provide clinically meaningful and statistically significant reductions in convulsive seizure frequency in children and adolescents (aged 2-18 years) with Dravet syndrome in two randomized, placebo-controlled clinical trials. The objective of this analysis was to assess longer-term safety and efficacy of fenfluramine in patients who completed one of the double-blind studies and entered an open-label extension (OLE) study.

METHODS

Patients enrolling in the OLE study initiated fenfluramine at 0.2 mg/kg/d regardless of their treatment assignment in the double-blind study. After 4 weeks, the fenfluramine dose could be titrated based on efficacy and tolerability to maximum of 0.7 mg/kg/d (absolute maximum 27 mg/d) or maximum of 0.4 mg/kg/d (absolute maximum 17 mg/d) in patients receiving concomitant stiripentol. The number and type of seizures were recorded daily in an electronic diary, and safety, including echocardiography, was assessed at Months 1, 2, and 3, and at 3-month intervals thereafter.

RESULTS

A total of 232 patients were enrolled as of March 13, 2018. During this analysis period, patients were treated for a median 256 days (range = 46-634 days). Over the entire OLE analysis period, the median decrease in convulsive seizure frequency compared to baseline in the double-blind studies was -66.8% (range = -100% to 234.9%; P < .001). The median reduction in seizure frequency was similar in patients <6 (-75.7%) and ≥6 years old (-64.7%). The most commonly reported adverse events included pyrexia (21.6%), nasopharyngitis (19.4%), and decreased appetite (-15.9%). No valvular heart disease (VHD) or pulmonary arterial hypertension (PAH) was observed.

SIGNIFICANCE

Study results demonstrate that fenfluramine provides clinically meaningful (≥50%) seizure frequency reduction over an extended period in patients with Dravet syndrome. No patient developed VHD or PAH, and fenfluramine was generally well tolerated.

Predicting Transdermal Uptake of Phthalates and a Paraben from Cosmetic Cream Using the Measured Fugacity

Transdermal uptake models compliment in vitro and in vivo experiments in assessing risk of environmental exposures to semivolatile organic compounds (SVOCs). A key parameter for mechanistic models is the chemical driving force for mass transfer from environmental media to human skin. In this research, we measure this driving force in the form of fugacity for chemicals in cosmetic cream and use it to model uptake from cosmetics as a surrogate for condensed environmental media. A simple cosmetic cream, containing no target analytes, was mixed with diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), and butyl paraben (BP) and diluted to make creams with concentrations ranging from 0.025% to 6%. The fugacity, relative to the pure compound, was measured using solid-phase micro extraction (SPME). We found that the relationship between the concentration and fugacity is highly nonlinear. The relative fugacity of the chemicals for a 2% w/w formulation was used in a diffusion-based model to predict transdermal uptake of each chemical and was compared with excretion data from a prior human subject study with the same formulation. Dynamic simulations of excretion are generally consistent with the results of the human subject experiment but sensitive to the input parameters, especially the time between cream application and showering.

Fenfluramine for Treatment-Resistant Seizures in Patients With Dravet Syndrome Receiving Stiripentol-Inclusive Regimens: A Randomized Clinical Trial

Importance

Fenfluramine treatment may reduce monthly convulsive seizure frequency in patients with Dravet syndrome who have poor seizure control with their current stiripentol-containing antiepileptic drug regimens.

Objective

To determine whether fenfluramine reduced monthly convulsive seizure frequency relative to placebo in patients with Dravet syndrome who were taking stiripentol-inclusive regimens.

Design, Setting, and Participants

This double-blind, placebo-controlled, parallel-group randomized clinical trial was conducted in multiple centers. Eligible patients were children aged 2 to 18 years with a confirmed clinical diagnosis of Dravet syndrome who were receiving stable, stiripentol-inclusive antiepileptic drug regimens.

Interventions

Patients with 6 or more convulsive seizures during the 6-week baseline period were randomly assigned to receive fenfluramine, 0.4 mg/kg/d (maximum, 17 mg/d), or a placebo. After titration (3 weeks), patients' assigned dosages were maintained for 12 additional weeks. Caregivers recorded seizures via a daily electronic diary.

Main Outcomes and Measures

The primary efficacy end point was the change in mean monthly convulsive seizure frequency between fenfluramine and placebo during the combined titration and maintenance periods relative to baseline.

Results

A total of 115 eligible patients were identified; of these, 87 patients (mean [SD], age 9.1 [4.8] years; 50 male patients [57%]; mean baseline frequency of seizures, approximately 25 convulsive seizures per month) were enrolled and randomized to fenfluramine, 0.4 mg/kg/d (n = 43) or placebo (n = 44). Patients treated with fenfluramine achieved a 54.0% (95% CI, 35.6%-67.2%; P < .001) greater reduction in mean monthly convulsive seizure frequency than those receiving the placebo. With fenfluramine, 54% of patients demonstrated a clinically meaningful (≥50%) reduction in monthly convulsive seizure frequency vs 5% with placebo (P < .001). The median (range) longest seizure-free interval was 22 (3.0-105.0) days with fenfluramine and 13 (1.0-40.0) days with placebo (P = .004). The most common adverse events were decreased appetite (19 patients taking fenfluramine [44%] vs 5 taking placebo [11%]), fatigue (11 [26%] vs 2 [5%]), diarrhea (10 [23%] vs 3 [7%]), and pyrexia (11 [26%] vs 4 [9%]). Cardiac monitoring demonstrated no clinical or echocardiographic evidence of valvular heart disease or pulmonary arterial hypertension.

Conclusions and Relevance

Fenfluramine demonstrated significant improvements in monthly convulsive seizure frequency in patients with Dravet syndrome whose conditions were insufficiently controlled with stiripentol-inclusive antiepileptic drug regimens. Fenfluramine was generally well tolerated. Fenfluramine may represent a new treatment option for Dravet syndrome.

Trial Registration

ClinicalTrials.gov identifier: NCT02926898.

Fenfluramine hydrochloride for the treatment of seizures in Dravet syndrome: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Dravet syndrome is a rare, treatment-resistant developmental epileptic encephalopathy characterised by multiple types of frequent, disabling seizures. Fenfluramine has been reported to have antiseizure activity in observational studies of photosensitive epilepsy and Dravet syndrome. The aim of the present study was to assess the efficacy and safety of fenfluramine in patients with Dravet syndrome.

METHODS

In this randomised, double-blind, placebo-controlled clinical trial, we enrolled children and young adults with Dravet syndrome. After a 6-week observation period to establish baseline monthly convulsive seizure frequency (MCSF; convulsive seizures were defined as hemiclonic, tonic, clonic, tonic-atonic, generalised tonic-clonic, and focal with clearly observable motor signs), patients were randomly assigned through an interactive web response system in a 1:1:1 ratio to placebo, fenfluramine 0·2 mg/kg per day, or fenfluramine 0·7 mg/kg per day, added to existing antiepileptic agents for 14 weeks. The primary outcome was the change in mean monthly frequency of convulsive seizures during the treatment period compared with baseline in the 0·7 mg/kg per day group versus placebo; 0·2 mg/kg per day versus placebo was assessed as a key secondary outcome. Analysis was by modified intention to treat. Safety analyses included all participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov with two identical protocols NCT02682927 and NCT02826863.

FINDINGS

Between Jan 15, 2016, and Aug 14, 2017, we assessed 173 patients, of whom 119 patients (mean age 9·0 years, 64 [54%] male) were randomly assigned to receive either fenfluramine 0·2 mg/kg per day (39), fenfluramine 0·7 mg/kg per day (40) or placebo (40). During treatment, the median reduction in seizure frequency was 74·9% in the fenfluramine 0·7 mg/kg group (from median 20·7 seizures per 28 days to 4·7 seizures per 28 days), 42·3% in the fenfluramine 0·2 mg/kg group (from median 17·5 seizures per 28 days to 12·6 per 28 days), and 19·2% in the placebo group (from median 27·3 per 28 days to 22·0 per 28 days). The study met its primary efficacy endpoint, with fenfluramine 0·7 mg/kg per day showing a 62·3% greater reduction in mean MCSF compared with placebo (95% CI 47·7-72·8, p<0·0001); fenfluramine 0·2 mg/kg per day showed a 32·4% reduction in mean MCSF compared with placebo (95% CI 6·2-52·3, p=0·0209). The most common adverse events (occurring in at least 10% of patients and more frequently in the fenfluramine groups) were decreased appetite, diarrhoea, fatigue, lethargy, somnolence, and decreased weight. Echocardiographic examinations revealed valve function within the normal physiological range in all patients during the trial and no signs of pulmonary arterial hypertension.

INTERPRETATION

In Dravet syndrome, fenfluramine provided significantly greater reduction in convulsive seizure frequency compared with placebo and was generally well tolerated, with no observed valvular heart disease or pulmonary arterial hypertension. Fenfluramine could be an important new treatment option for patients with Dravet syndrome.

FUNDING

Zogenix.

Ten questions concerning the implications of carpet on indoor chemistry and microbiology

Carpet and rugs currently represent about half of the United States flooring market and offer many benefits as a flooring type. How carpets influence our exposure to both microorganisms and chemicals in indoor environments has important health implications but is not well understood. The goal of this manuscript is to consolidate what is known about how carpet impacts indoor chemistry and microbiology, as well as to identify the important research gaps that remain. After describing the current use of carpet indoors, questions focus on five specific areas: 1) indoor chemistry, 2) indoor microbiology, 3) resuspension and exposure, 4) current practices and future needs, and 5) sustainability. Overall, it is clear that carpet can influence our exposures to particles and volatile compounds in the indoor environment by acting as a direct source, as a reservoir of environmental contaminants, and as a surface supporting chemical and biological transformations. However, the health implications of these processes are not well known, nor how cleaning practices could be optimized to minimize potential negative impacts. Current standards and recommendations focus largely on carpets as a primary source of chemicals and on limiting moisture that would support microbial growth. Future research should consider enhancing knowledge related to the impact of carpet in the indoor environment and how we might improve the design and maintenance of this common material to reduce our exposure to harmful contaminants while retaining the benefits to consumers.

Indoor boundary layer chemistry modeling

Ozone (O₃ ) chemistry is thought to dominate the oxidation of indoor surfaces. We consider the hypothesis that reactions taking place within indoor boundary layers result in greater than anticipated hydroxyl radical (OH) deposition rates. We develop models that account for boundary layer mass-transfer phenomena, O₃ -terpene chemistry and OH formation, removal, and deposition; we solve these analytically and by applying numerical methods. For an O₃ -limonene system, we find that OH flux to a surface with an O₃ reaction probability of 10^-8 is 4.3 × 10^-5 molec/(cm² s) which is about 10 times greater than predicted by a traditional boundary layer theory. At very low air exchange rates the OH surface flux can be as much as 10% of that for O₃ . This effect becomes less pronounced for more O₃ -reactive surfaces. Turbulence intensity does not strongly influence the OH concentration gradient except for surfaces with an O₃ reaction probability >10^-4 . Although the O₃ flux dominates OH flux under most conditions, OH flux can be responsible for as much as 10% of total oxidant uptake to otherwise low-reactivity surfaces. Further, OH chemistry differs from that for ozone; therefore, its deposition is important in understanding the chemical evolution of some indoor surfaces and surface films.

Indoor ozone/human chemistry and ventilation strategies

This study aimed to better understand and quantify the influence of ventilation strategies on occupant-related indoor air chemistry. The oxidation of human skin oil constituents was studied in a continuously ventilated climate chamber at two air exchange rates (1 h^-1 and 3 h^-1 ) and two initial ozone mixing ratios (30 and 60 ppb). Additional measurements were performed to investigate the effect of intermittent ventilation ("off" followed by "on"). Soiled t-shirts were used to simulate the presence of occupants. A time-of-flight-chemical ionization mass spectrometer (ToF-CIMS) in positive mode using protonated water clusters was used to measure the oxygenated reaction products geranyl acetone, 6-methyl-5-hepten-2-one (6-MHO) and 4-oxopentanal (4-OPA). The measurement data were used in a series of mass balance models accounting for formation and removal processes. Reactions of ozone with squalene occurring on the surface of the t-shirts are mass transport limited; ventilation rate has only a small effect on this surface chemistry. Ozone-squalene reactions on the t-shirts produced gas-phase geranyl acetone, which was subsequently removed almost equally by ventilation and further reaction with ozone. About 70% of gas-phase 6-MHO was produced in surface reactions on the t-shirts, the remainder in secondary gas-phase reactions of ozone with geranyl acetone. 6-MHO was primarily removed by ventilation, while further reaction with ozone was responsible for about a third of its removal. 4-OPA was formed primarily on the surfaces of the shirts (~60%); gas-phase reactions of ozone with geranyl acetone and 6-MHO accounted for ~30% and ~10%, respectively. 4-OPA was removed entirely by ventilation. The results from the intermittent ventilation scenarios showed delayed formation of the reaction products and lower product concentrations compared to continuous ventilation.

Analysis of indoor particles and gases and their evolution with natural ventilation

The air composition and reactivity from outdoor and indoor mixing field campaign was conducted to investigate the impacts of natural ventilation (ie, window opening and closing) on indoor air quality. In this study, a thermal desorption aerosol gas chromatograph (TAG) obtained measurements of indoor particle- and gas-phase semi- and intermediately volatile organic compounds both inside and outside a single-family test home. Together with measurements from a suite of instruments, we use TAG data to evaluate changes in indoor particles and gases at three natural ventilation periods. Positive matrix factorization was performed on TAG and adsorbent tube data to explore five distinct chemical and physical processes occurring in the indoor environment. Outdoor-to-indoor transport is observed for sulfate, isoprene epoxydiols, polycyclic aromatic hydrocarbons, and heavy alkanes. Dilution of indoor species is observed for volatile, non-reactive species including methylcyclohexane and decamethylcyclopentasiloxane. Window opening drives enhanced emissions of semi- and intermediately volatile species including TXIB, DEET, diethyl phthalate, and carvone from indoor surfaces. Formation via enhanced oxidation was observed for nonanal and 2-decanone when outdoor oxidants entered the home. Finally, oxidative depletion of gas-phase terpenes (eg, limonene and α-pinene) was anticipated but not observed due to limited measurement resolution and dynamically changing conditions.

Modelling consortium for chemistry of indoor environments (MOCCIE): integrating chemical processes from molecular to room scales

We report on the development of a modelling consortium for chemistry in indoor environments that connects models over a range of spatial and temporal scales, from molecular to room scales and from sub-nanosecond to days, respectively. Our modeling approaches include molecular dynamics (MD) simulations, kinetic process modeling, gas-phase chemistry modeling, organic aerosol modeling, and computational fluid dynamics (CFD) simulations. These models are applied to investigate ozone reactions with skin and clothing, oxidation of volatile organic compounds and formation of secondary organic aerosols, and mass transport and partitioning of indoor species to surfaces. MD simulations provide molecular pictures of limonene adsorption on SiO2 and ozone interactions with the skin lipid squalene, providing kinetic parameters such as surface accommodation coefficient, desorption lifetime, and bulk diffusivity. These parameters then constrain kinetic process models, which resolve mass transport and chemical reactions in gas and condensed phases for analysis of experimental data. A detailed indoor chemical box model is applied to simulate α-pinene ozonolysis with improved representation of gas-particle partitioning. Application of 2D-volatility basis set reveals that OH-induced aging sometimes drives increases in indoor organic aerosol concentrations, due to organic mass functionalization and enhanced partitioning. CFD simulations show that concentrations of ozone and primary product change near the human surface rapidly, indicating non-uniform spatial distributions from the occupant surface to ambient air, while secondary ozone product is relatively well-mixed throughout the room. This development establishes a framework to integrate different modeling tools and experimental measurements, opening up an avenue for development of comprehensive and integrated models with representations of various chemistry in indoor environments.

Dynamics of Residential Water-Soluble Organic Gases: Insights into Sources and Sinks

Water-soluble organic gas (WSOG) concentrations are elevated in homes. However, WSOG sources, sinks, and concentration dynamics are poorly understood. We observed substantial variations in 23 residential indoor WSOG concentrations measured in real time in a North Carolina, U.S., home over several days with a high-resolution time-of-flight chemical ionization mass spectrometer equipped with iodide reagent ion chemistry (I-HR-ToF-CIMS). Concentrations of acetic, formic, and lactic acids ranged from 30-130, 15-53, and 2.5-360 μg m-3, respectively. Concentrations of several WSOGs, including acetic and formic acids, decreased considerably (∼30-50%) when the air conditioner (AC) cycled on, suggesting that the AC system is an important sink for indoor WSOGs. In contrast to nonpolar organic gases, indoor WSOG loss rate coefficients were substantial for compounds with high oxygen-to-carbon (O/C) ratios (e.g., 1.6-2.2 h-1 for compounds with O/C > 0.75 when the AC system was off). Loss rate coefficients in the AC system were more uncertain but were estimated to be 1.5 h-1. Elevated concentrations of lactic acid coincided with increased human occupancy and cooking. We report several WSOGs emitted from cooking and cleaning as well as transported in from outdoors. In addition to indoor air chemistry, these results have implications to exposure and human health.

Dermal uptake of nicotine from air and clothing: Experimental verification

This study aims to elucidate in greater detail the dermal uptake of nicotine from air or from nicotine-exposed clothes, which was demonstrated recently in a preliminary study. Six non-smoking participants were exposed to gaseous nicotine (between 236 and 304 μg/m³ ) over 5 hours while breathing clean air through a hood. Four of the participants wore only shorts and 2 wore a set of clean clothes. One week later, 2 of the bare-skinned participants were again exposed in the chamber, but they showered immediately after exposure instead of the following morning. The 2 participants who wore clean clothes on week 1 were now exposed wearing a set of clothes that had been exposed to nicotine. All urine was collected for 84 hours after exposure and analyzed for nicotine and its metabolites, cotinine and 3OH-cotinine. All participants except those wearing fresh clothes excreted substantial amounts of biomarkers, comparable to levels expected from inhalation intake. Uptake for 1 participant wearing exposed clothes exceeded estimated intake via inhalation by >50%. Biomarker excretion continued during the entire urine collection period, indicating that nicotine accumulates in the skin and is released over several days. Absorbed nicotine was significantly lower after showering in 1 subject but not the other. Differences in the normalized uptakes and in the excretion patterns were observed among the participants. The observed cotinine half-lives suggest that non-smokers exposed to airborne nicotine may receive a substantial fraction through the dermal pathway. Washing skin and clothes exposed to nicotine may meaningfully decrease exposure.

Linking a dermal permeation and an inhalation model to a simple pharmacokinetic model to study airborne exposure to di(n-butyl) phthalate

Six males clad only in shorts were exposed to high levels of airborne di(n-butyl) phthalate (DnBP) and diethyl phthalate (DEP) in chamber experiments conducted in 2014. In two 6 h sessions, the subjects were exposed only dermally while breathing clean air from a hood, and both dermally and via inhalation when exposed without a hood. Full urine samples were taken before, during, and for 48 h after leaving the chamber and measured for key DnBP and DEP metabolites. The data clearly demonstrated high levels of DnBP and DEP metabolite excretions while in the chamber and during the first 24 h once leaving the chamber under both conditions. The data for DnBP were used in a modeling exercise linking dose models for inhalation and transdermal permeation with a simple pharmacokinetic model that predicted timing and mass of metabolite excretions. These models were developed and calibrated independent of these experiments. Tests included modeling of the "hood-on" (transdermal penetration only), "hood-off" (both inhalation and transdermal) scenarios, and a derived "inhalation-only" scenario. Results showed that the linked model tended to duplicate the pattern of excretion with regard to timing of peaks, decline of concentrations over time, and the ratio of DnBP metabolites. However, the transdermal model tended to overpredict penetration of DnBP such that predictions of metabolite excretions were between 1.1 and 4.5 times higher than the cumulative excretion of DnBP metabolites over the 54 h of the simulation. A similar overprediction was not seen for the "inhalation-only" simulations. Possible explanations and model refinements for these overpredictions are discussed. In a demonstration of the linked model designed to characterize general population exposures to typical airborne indoor concentrations of DnBP in the United States, it was estimated that up to one-quarter of total exposures could be due to inhalation and dermal uptake.

Advanced buffer materials for indoor air CO2 control in commercial buildings

In this study, we evaluated solid sorbents for their ability to passively control indoor CO₂ concentration in buildings or rooms with cyclic occupancy (eg, offices, bedrooms). Silica supported amines were identified as suitable candidates and systematically evaluated in the removal of CO₂ from indoor air by equilibrium and dynamic techniques. In particular, sorbents with various amine loadings were synthesized using tetraethylenepentamine (TEPA), poly(ethyleneimine) (PEI) and a silane coupling agent 3-aminopropyltriethoxysilane (APS). TGA analysis indicates that TEPA impregnated silica not only displays a relatively high adsorption capacity when exposed to ppm level CO₂ concentrations, but also is capable of desorbing the majority of CO₂ by air flow (eg, by concentration gradient). In 10 L flow-through chamber experiments, TEPA-based sorbents reduced outlet CO₂ by up to 5% at 50% RH and up to 93% of CO₂ adsorbed over 8 hours was desorbed within 16 hours. In 8 m³ flow-through chamber experiments, 18 g of the sorbent powder spread over a 2 m² area removed approximately 8% of CO₂ injected. By extrapolating these results to real buildings, we estimate that meaningful reductions in the CO₂ can be achieved, which may help reduce energy requirements for ventilation and/or improve air quality.

Measurements of dermal uptake of nicotine directly from air and clothing

In this preliminary study, we have investigated whether dermal uptake of nicotine directly from air or indirectly from clothing can be a meaningful exposure pathway. Two participants wearing only shorts and a third participant wearing clean cotton clothes were exposed to environmental tobacco smoke (ETS), generated by mechanically "smoking" cigarettes, for three hours in a chamber while breathing clean air from head-enveloping hoods. The average nicotine concentration (420 μg/m³ ) was comparable to the highest levels reported for smoking sections of pubs. Urine samples were collected immediately before exposure and 60 hour post-exposure for bare-skinned participants. For the clothed participant, post-exposure urine samples were collected for 24 hour. This participant then entered the chamber for another three-hour exposure wearing a hood and clothes, including a shirt that had been exposed for five days to elevated nicotine levels. The urine samples were analyzed for nicotine and two metabolites-cotinine and 3OH-cotinine. Peak urinary cotinine and 3OH-cotinine concentrations for the bare-skinned participants were comparable to levels measured among non-smokers in hospitality environments before smoking bans. The amount of dermally absorbed nicotine for each bare-skinned participant was conservatively estimated at 570 μg, but may have been larger. For the participant wearing clean clothes, uptake was ~20 μg, and while wearing a shirt previously exposed to nicotine, uptake was ~80 μg. This study demonstrates meaningful dermal uptake of nicotine directly from air or from nicotine-exposed clothes. The findings are especially relevant for children in homes with smoking or vaping.

Outcomes Assessment in Clinical Trials of Alzheimer's Disease and its Precursors: Readying for Short-term and Long-term Clinical Trial Needs

An evolving paradigm shift in the diagnostic conceptualization of Alzheimer's disease is reflected in its recently updated diagnostic criteria from the National Institute on Aging-Alzheimer's Association and the International Working Group. Additionally, it is reflected in the increased focus in this field on conducting prevention trials in addition to improving cognition and function in people with dementia. These developments are making key contributions towards defining new regulatory thinking around Alzheimer's disease treatment earlier in the disease continuum. As a result, the field as a whole is now concentrated on exploring the next-generation of cognitive and functional outcome measures that will support clinical trials focused on treating the slow slide into cognitive and functional impairment. With this backdrop, the International Society for CNS Clinical Trials and Methodology convened semi-annual working group meetings which began in spring of 2012 to address methodological issues in this area. This report presents the most critical issues around primary outcome assessments in Alzheimer's disease clinical trials, and summarizes the presentations, discussions, and recommendations of those meetings, within the context of the evolving landscape of Alzheimer's disease clinical trials.

Diagnostic accuracy of DXA compared to conventional spine radiographs for the detection of vertebral fractures in children

OBJECTIVES

In children, radiography is performed to diagnose vertebral fractures and dual energy x-ray absorptiometry (DXA) to assess bone density. In adults, DXA assesses both. We aimed to establish whether DXA can replace spine radiographs in assessment of paediatric vertebral fractures.

METHODS

Prospectively, lateral spine radiographs and lateral spine DXA of 250 children performed on the same day were independently scored by three radiologists using the simplified algorithm-based qualitative technique and blinded to results of the other modality. Consensus radiograph read and second read of 100 random images were performed. Diagnostic accuracy, inter/intraobserver and intermodality agreements, patient/carer experience and radiation dose were assessed.

RESULTS

Average sensitivity and specificity (95 % confidence interval) in diagnosing one or more vertebral fractures requiring treatment was 70 % (58-82 %) and 97 % (94-100 %) respectively for DXA and 74 % (55-93 %) and 96 % (95-98 %) for radiographs. Fleiss' kappa for interobserver and average kappa for intraobserver reliability were 0.371 and 0.631 respectively for DXA and 0.418 and 0.621 for radiographs. Average effective dose was 41.9 μSv for DXA and 232.7 μSv for radiographs. Image quality was similar.

CONCLUSION

Given comparable image quality and non-inferior diagnostic accuracy, lateral spine DXA should replace conventional radiographs for assessment of vertebral fractures in children.

KEY POINTS

• Vertebral fracture diagnostic accuracy of lateral spine DXA is non-inferior to radiographs. • The rate of unreadable vertebrae for DXA is lower than for radiographs. • Effective dose of DXA is significantly lower than radiographs. • Children prefer DXA to radiographs. • Given the above, DXA should replace radiographs for paediatric vertebral fracture assessment.

Alignment and component position after patient-matched instrumentation versus conventional total knee arthroplasty

PURPOSE

To compare patient-matched instrumentation (PMI) with conventional total knee arthroplasty (TKA) in terms of limb alignment and component position.

METHODS

Nine men and 36 women (mean age, 69.5 years) who underwent PMI TKA were compared with 20 men and 25 women (mean age, 69.3 years) who underwent conventional TKA by the same team of surgeons with the same prosthesis and protocols in terms of limb alignment and component position using the Perth protocol computed tomography, as well as bone resection measurements, operating time, and the number of trays used.

RESULTS

The PMI and conventional TKA groups were comparable in terms of age, body mass index, tourniquet time, operating time, and the number of trays used. For limb alignment and component position, the 2 groups differed significantly in sagittal femoral component position (2.4º vs. 0.9º, p=0.0008) and the percentage of knees with femoral component internally rotated ≥1° with respect to the transepicondylar axis (20% vs. 55%, p=0.001). The difference was not significant in terms of limb alignment, coronal and rotational femoral component position, or coronal and sagittal tibial component position. Intra-operatively, all patient-matched cutting blocks demonstrated acceptable fit and stability. No instrument-related adverse events or complications were encountered. One (2.2%) femur and 6 (13.3%) tibiae were recut 2 mm for optimal ligament balancing. Two femoral components were upsized to the next size, and 2 tibial components were upsized and 2 downsized to the next size.

CONCLUSION

PMI was as accurate as conventional instrumentation in TKA. There was no significant difference in limb alignment or femoral and tibial component position in the coronal and sagittal planes between PMI and conventional TKA. PMI had a higher tendency to achieve correct femoral component rotation.

Methamphetamine absorption by skin lipids: accumulated mass, partition coefficients, and the influence of fatty acids

Occupants of former methamphetamine laboratories, often residences, may experience increased exposure through the accumulation of the methamphetamine in the organic films that coat skin and indoor surfaces. The objectives of this study were to determine equilibrium partition coefficients of vapor-phase methamphetamine with artificial sebum (AS-1), artificial sebum without fatty acids (AS-2), and real skin surface films, herein called skin oils. Sebum and skin oil-coated filters were exposed to vapor-phase methamphetamine at concentrations ranging from 8 to 159 ppb, and samples were analyzed for exposure time periods from 2 h to 60 days. For a low vapor-phase methamphetamine concentration range of ~8-22 ppb, the equilibrium partition coefficient for AS-1 was 1500 ± 195 μg/g/ppb. For a high concentration range of 98-112 ppb, the partition coefficient was lower, 459 ± 80 μg/g/ppb, suggesting saturation of the available absorption capacity. The low partition coefficient for AS-2 (33 ± 6 μg/g/ppb) suggests that the fatty acids in AS-1 and skin oil are responsible for much high partition coefficients. We predict that the methamphetamine concentration in skin lipids coating indoor surfaces can exceed recommended surface remediation standards even for air concentrations well below 1 ppb.

Benefit-cost analysis of commercially available activated carbon filters for indoor ozone removal in single-family homes

This study involved the development of a model for evaluating the potential costs and benefits of ozone control by activated carbon filtration in single-family homes. The modeling effort included the prediction of indoor ozone with and without activated carbon filtration in the HVAC system. As one application, the model was used to predict benefit-to-cost ratios for single-family homes in 12 American cities in five different climate zones. Health benefits were evaluated using disability-adjusted life-years and included city-specific age demographics for each simulation. Costs of commercially available activated carbon filters included capital cost differences when compared to conventional HVAC filters of similar particle removal efficiency, energy penalties due to additional pressure drop, and regional utility rates. The average indoor ozone removal effectiveness ranged from 4 to 20% across the 12 target cities and was largely limited by HVAC system operation time. For the parameters selected in this study, the mean predicted benefit-to-cost ratios for 1-inch filters were >1.0 in 10 of the 12 cities. The benefits of residential activated carbon filters were greatest in cities with high seasonal ozone and HVAC usage, suggesting the importance of targeting such conditions for activated carbon filter applications.

Cognitive Health Assessment and Establishment of a Virtual Cohort of Dementia Caregivers

Background

Many factors impact caregivers’ cognitive health and, by extension, their ability to provide care. This study examined the relationship between psychosocial factors and cognitive performance among dementia caregivers and established a virtual cohort of caregivers for future research.

Methods

Data on 527 caregivers were collected via a Web-based survey that assessed cognitive performance. Caregiver data were compared to corresponding data from 527 age-, race-, gender-, and education-matched controls from a normative database. Caregiver self-reported sleep, stress, health, and social support were also assessed.

Results

Caregivers performed significantly worse than controls on 3 of 5 cognitive subtests. Stress, sleep, perceived support, self-rated health, years of caregiving, race, and gender were significant predictors of cognitive performance.

Conclusion

In this sample of dementia caregivers, psychosocial factors interacted in complex ways to impact cognitive performance. Further investigation is needed to better understand how these factors affect cognitive performance among caregivers. This could be accomplished by the establishment of a virtual cohort that facilitates the development of digital tools to support the evaluation and management of caregiver needs in a manner that helps them remain effective in their caregiving roles.

UK service level audit of insulin pump therapy in paediatrics

AIM

To conduct an audit of insulin pump therapy in the UK after the issue of guidelines for the use of continuous subcutaneous insulin infusion by NICE in 2008 (Technology Appraisal 151).

METHODS

All centres in the UK, providing pump services to children and young people were invited to participate in an online audit. Audit metrics were aligned to NICE Technology Appraisal 151 and an electronic data collection tool was used.

RESULTS

Of the 176 UK centres identified as providing pump services, 166 (94.3%) participated in the study. A total of 5094 children and young people were identified as using continuous subcutaneous insulin infusion (19% of all paediatric patients with Type 1 diabetes), with a median (range) of 16.9 (0.67-69.4)% per centre. Units had a median of 0.58 consultant sessions, 0.43 full-time equivalent diabetic specialist nurses, and 0.1 full-time equivalent dieticians delivering the pump service. The majority of this time was not formally funded. Families could access 24-h clinical and technical support (83% units), although the delivery varied between consultant, diabetic specialist nurse and company representatives. Only 53% of units ran, or accessed, structured education programmes for continuous subcutaneous insulin infusion use. Most units (86%) allowed continuous subcutaneous insulin infusion use for paediatric inpatients, but only 56% had written guidelines for this scenario. Nine percent of units had encountered funding refusal for a patient fulfilling NICE (Technology Appraisal 151) criteria.

CONCLUSION

The number of children and young people on continuous subcutaneous insulin infusion therapy is consistent with numbers estimated by NICE. There is a worrying lack of funded healthcare professional time. The audit also identified gaps in the provision of structured education and absence of written inpatient guidelines.

Epilepsy surgery related to pediatric brain tumors: Miami Children's Hospital experience

OBJECT

Pediatric brain tumors may be associated with medically intractable epilepsy for which surgery is indicated. The authors sought to evaluate the efficacy of epilepsy surgery for seizure control in pediatric patients with brain tumors.

METHODS

The authors performed a retrospective review of consecutive patients undergoing resective epilepsy surgery related to pediatric brain tumors at Miami Children's Hospital between June 1986 and June 2014. Time-to-event analysis for seizure recurrence was performed; an "event" was defined as any seizures that occurred following resective epilepsy surgery, not including seizures and auras in the 1st postoperative week. The authors analyzed several preoperative variables to determine their suitability to predict seizure recurrence following surgery.

RESULTS

Eighty-four patients (47 males) with a mean age (± standard deviation) of 8.7 ± 5.5 years (range 0.5-21.6 years) were included. The study included 39 (46%) patients with gliomas, 20 (24%) with dysembryoplastic neuroepithelial tumors (DNETs), 14 (17%) with gangliogliomas, and 11 (13%) with other etiologies. Among the patients with gliomas, 18 were classified with low-grade glioma, 5 had oligodendroglioma, 6 had uncategorized astrocytoma, 3 had pilocytic astrocytoma, 3 had pleomorphic xanthoastrocytoma, 3 had glioblastoma, and 1 had gliomatosis cerebri. Seventy-nine (94.0%) resections were guided by intraoperative electrocorticography (ECoG). The mean time (± standard deviation) to seizure recurrence was 81.8 ± 6.3 months. Engel Class I outcome was achieved in 66 (78%) and 63 (75%) patients at 1 and 2 years' follow-up, respectively. Patients with ganglioglioma demonstrated the highest probability of long-term seizure freedom, followed by patients with DNETs and gliomas. In univariate analyses, temporal location (HR 1.75, 95% CI 0.26-1.27, p = 0.171) and completeness of resection (HR 1.69, 95% CI 0.77-3.74, p = 0.191) demonstrated a trend toward a longer duration of seizure freedom.

CONCLUSIONS

ECoG-guided epilepsy surgery for pediatric patients with brain tumors is highly effective. Tumors located in the temporal lobe and those in which a complete ECoG-guided resection is performed may result in a greater likelihood of long-term seizure freedom.

Accumulation of gas-phase methamphetamine on clothing, toy fabrics, and skin oil

To better understand methamphetamine exposure and risk for occupants of former residential clandestine methamphetamine laboratories, we measured the dynamic accumulation of methamphetamine in skin oil, cotton and polyester (PE) clothing, upholstery, and toy fabric (substrates) exposed to 15-30 ppb (91-183 μg/m(3)) neutral methamphetamine in air for up to 60 days. The average equilibrium partition coefficients at 30% RH, in units of μg of methamphetamine per gram of substrate per ppb, are 3.0 ± 0.2 for a PE baby blanket, 5.6 ± 3.5 for a PE fabric toy, 3.7 ± 0.2 for a PE shirt, 18.3 ± 8.0 for a PE/cotton upholstery fabric, and 1200 ± 570 in skin oil. The partition coefficients at 60% RH are 4.5 ± 0.4, 5.2 ± 2.1, 4.5 ± 0.6, 36.1 ± 3.6, and 1600 ± 1100 μg/(g ppb), respectively. There was no difference in the partition coefficient for a clean and skin-oil-soiled cotton shirt [15.3 ± 2.1 μg/(g ppb) @ 42 days]. Partition coefficients for skin oil may be sensitive to composition. 'Mouthing' of cloth is predicted to be the dominant exposure pathway [60 μg/(kg body weight*ppb)] for a toddler in former meth lab, and indoor air concentrations would have to be very low (0.001 ppb) to meet the recommended reference dose for children.

PRACTICAL IMPLICATIONS

Gas-phase methamphetamine transfers to and accumulates on clothing, toys and other fabrics significantly increases risk of ingestion of methamphetamine. Current remediation methods should consider measurement of postremediation gas-phase air concentrations of methamphetamine in addition to surface wipe samples.

Fibrous dysplasia: management of the optic canal

BACKGROUND

Fibrous dysplasia is an abnormal growth of bone that can lead to severe facial disfigurement. A dreaded outcome is compression of the optic nerve, leading to blindness. Controversy has surrounded the role of optic nerve unroofing for circumferential involvement of the optic canal. At present, many neurosurgeons unroof the nerve therapeutically in the setting of optic nerve dysfunction. Prophylactic unroofing (i.e., unroofing the nerve prior to the development of visual symptoms) has been previously proposed, although reported outcomes have been mixed. The authors present their long-term results of patients who have undergone optic nerve unroofing.

METHODS

From 1975 to 2012, patients with fibrous dysplasia were investigated. Their age, demographics, operative procedure, optic nerve involvement (radiologically and clinically), and long-term outcomes and complications were recorded.

RESULTS

Over 37 years, the senior author (S.A.W.) operated on 32 patients with fibrous dysplasia. Average follow-up was 5 years. Nine patients underwent optic nerve unroofing. Two patients had bilateral unroofing. Three patients who underwent therapeutic optic nerve unroofing ultimately went on to complete vision loss. The remaining seven patients who underwent prophylactic unroofing had no immediate postoperative visual compromise.

CONCLUSIONS

Therapeutic optic nerve unroofing is advocated in fibrous dysplasia patients with continuous deterioration of vision. However, the authors believe prophylactic unroofing is safe, and it should be performed not necessarily as a primary surgical procedure, but as a procedure along with excision of fibrous dysplasia in the anterior skull base during the same operation performed for orbitocranial deformity.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

The U.K. service level audit of insulin pump therapy in adults

AIMS

The National Institute for Health and Clinical Excellence (NICE) published guidelines for the use of continuous subcutaneous insulin infusion in 2008 (technology appraisal 151). The first U.K.-wide insulin pump audit took place in 2012 with the aim of determining adherence to the guidance issued in NICE technology appraisal 151. The results of the adult service level audit are reported here.

METHODS

All centres providing continuous subcutaneous insulin infusion services to adults with diabetes in the U.K. were invited to participate. Audit metrics were aligned to technology appraisal 151. Data entry took place online using a DiabetesE formatted data collection tool.

RESULTS

One hundred and eighty-three centres were identified as delivering adult continuous subcutaneous insulin infusion services in the U.K., of which 178 (97.3%) participated in the audit. At the time of the audit, 13 428 adults were using insulin pump therapy, giving an estimated prevalence of use of 6%. Ninety-three per cent of centres did not report any barriers in obtaining funding for patients who fulfilled NICE criteria. The mean number of consultant programmed activities dedicated to continuous subcutaneous insulin infusion services was 0.96 (range 0-8), mean whole-time equivalent diabetes specialist nurses was 0.62 (range 0-3) and mean whole-time equivalent dietitian services was 0.3 (range 0-2), of which 39, 61 and 60%, respectively, were not formally funded.

CONCLUSIONS

The prevalence of continuous subcutaneous insulin infusion use in the U.K. falls well below the expectation of NICE (15-20%) and that of other European countries (> 15%) and the U.S.A. (40%). This may be attributable, in part, to lack of healthcare professional time needed for identification and training of new pump therapy users.

Surgical treatment of refractory status epilepticus in children: clinical article

OBJECT

Refractory status epilepticus (RSE) is a life-threatening neurological emergency associated with high morbidity and mortality. Affected patients often require prolonged intensive care and can suffer multiple complications. Surgical intervention to control RSE is rarely used but can obviate the risks of prolonged seizures and intensive care treatment. Authors of the present study analyzed their experience with the surgical management of patients suffering from RSE.

METHODS

The Epilepsy Surgery Database at Miami Children's Hospital was reviewed for patients who had undergone surgery for RSE. Clinical presentation, electrophysiological profile, radiological data, surgical details, and postoperative course were evaluated.

RESULTS

Between 1990 and 2012, 15 patients underwent surgery for uncontrolled seizures despite high-dose medical suppressive therapy. The mean preoperative duration of status epilepticus was 8 weeks. Ictal SPECT and FDG-PET imaging in conjunction with intraoperative electrophysiological studies helped to outline the extent of resection. Surgical intervention controlled seizures in all patients and facilitated the transition out of intensive care. Adverse events related to a prolonged intensive care unit stay included sepsis and respiratory complications. Four patients had worsened neurological function, developing hemiparesis and dysphasia. There was no operative mortality.

CONCLUSIONS

Surgical intervention can successfully control refractory partial status epilepticus, prevent associated morbidity, and decrease intensive care unit stay. Ictal SPECT and PET are valuable in guiding resection.

Effects of methylnaltrexone in patients with narcotic bowel syndrome: a pilot observational study

BACKGROUND

Narcotic bowel syndrome (NBS) describes disabling chronic severe abdominal pain that worsens despite continuing or escalating doses of opiates. Therapy is very limited.

AIM

To examine effects of blocking peripheral µ-opioid receptors on the symptomatology of patients with NBS and its safety.

METHODS

An open-label observational study was performed in four women with NBS. After a 2-week run-in period, patients were treated for 12 weeks with 8-12 mg methylnaltrexone bromide subcutaneously every other day, increasing to daily if there was poor response. Patient and physician assessment was documented, and patients completed an eight-symptom visual analogue scale weekly and the Functional Assessment of Chronic Illnesses Therapy-Fatigue questionnaire for fatigue. Patients were observed for 4 weeks following withdrawal of the drug.

RESULTS

One patient was unable to tolerate the study medication because of worsening pain after injection, and withdrew. Two showed clear benefit with reduction of symptoms overall, pain, bloating, distension, nausea and tiredness, with improved satisfaction and consistency of bowel actions and fatigue scores. Both reduced analgesic usage. The third had improved ileostomy output and had no episodes of severe bloating, but pain scores remained high. All three worsened after drug withdrawal and requested retreatment. Three experienced abdominal pains of moderate severity for 30-60 min consistently within 5 min of each injection. No other adverse events were experienced.

CONCLUSIONS

Methylnaltrexone has a positive impact on symptoms in women with NBS, although treatment does induce transient pain following its administration. Larger studies are required to examine its efficacy and longer term safety in this patient group.

Survey of general practitioners' attitudes to prescribing statins in different patient groups: a web-based survey

Low rates of statin prescribing have been noted in several major studies of patients with schizophrenia and the aim of this study was to investigate clinicians' attitudes to prescribing statins to different patient groups. The general practitioners (GPs) in Dumfries and Galloway were randomized into two groups. They received an email invitation to a web-based survey. The survey asked for treatment recommendation for three patient vignettes, each with a 10-year cardiovascular risk of 20%. In one group descriptions of the patient included type 1 diabetes, epilepsy and unemployed and in the other group these were replaced by type 2 diabetes, schizophrenia and retired. The questionnaires had no other differences. After three email invites, 53 questionnaires were completed (40% of a potential 133 participants). Statin therapy was recommended by 88% and 85% of respondents for patients with type 1 and type 2 diabetes, respectively; by 37% of respondents for patients with schizophrenia and 31% for patients with epilepsy; by 33% of respondents for retired patients and 23% of respondents for patients who are unemployed. This study demonstrates under-prescribing of statins. This was not worse for patients with schizophrenia as compared with patients with epilepsy. This suggests that the low rates of treatment of metabolic risk factors in patients with schizophrenia are not the result of clinician bias when compared with patients with epilepsy. Clinician bias, however, may reduce the chances of an unemployed patient receiving statin treatment.

A solid phase extraction-liquid chromatographic-tandem mass spectrometry method for determination of concentrations of GDC-0941, a small molecule class I phosphatidylinositide 3-kinase inhibitor, to support clinical development

A solid phase extraction (SPE) liquid chromatographic-tandem mass spectrometry (LC-MS/MS) method for the determination of GDC-0941 concentrations in human plasma has been developed and validated to support clinical development. An Oasis MCX 10mg 96-well SPE plate was used to extract plasma samples (50 μL) and the resulting extracts were analyzed using reverse-phase chromatography and mass spectrometer coupled with a turbo-ionspray interface. The method was validated over the calibration curve range 0.500-500 ng/mL with linear regression and 1/x(2) weighting. Within-run relative standard deviation (%RSD) ranged from 1.5 to 11.5%, while the between-run %RSD varied from 0.0 to 4.4%. The accuracy ranged from 96.0% to 110.0% of nominal for within-run and 98.0% to 108.0% of nominal for between-run at all concentrations including the LLOQ quality control at 0.500 ng/mL. Extraction recovery of GDC-0941 was between 79.0% and 86.2%. Stability of GDC-0941 was established in human plasma for 602 days at -70 °C and 598 days at -20°C, respectively, and established in reconstituted sample extracts for 167 h when stored at room temperature. Internal standard normalized matrix factor was 1.1, demonstrating that the use of the stable-labeled internal standard GDC-0941-d(8) effectively compensated observed matrix effect and resulting in no adverse impact on the quality of the data produced. This assay was used for the determination of GDC-0941 human plasma concentrations over a sufficient time period to determine pharmacokinetic parameters at relevant clinical doses.

The role of continuous subcutaneous insulin infusion therapy in patients with diabetic gastroparesis

AIMS/OBJECTIVE

To describe the effectiveness of continuous subcutaneous insulin infusion (CSII) in patients with symptomatic diabetic gastroparesis and unstable glycaemic control.

METHODS

Data from 26 patients with symptomatic diabetic gastroparesis and unstable glycaemic control using multiple-dose insulin (MDI) regimens, and subsequently managed with CSII, were analysed.

RESULTS

Following initiation of CSII, the median length of inpatient bed days associated with hospital admissions related to gastroparesis and glycaemic instability was reduced from 8.5 (range 0-144) days patient( -1) year( -1) prior to CSII to 0 (range 0-15) days patient( -1) year( -1). The median HbA(1c) reduction with CSII was 1.8% (22 mmol/mol; p < 0.05). The median capillary blood glucose (CBG) with CSII was significantly lower than with MDI: 7.7 mmol/l (range 3.8-15.4 mmol/l) vs 9.8 mmol/l (range 2.3-27 mmol/l), respectively, p < 0.001. Glycaemic variability with CSII was significantly reduced compared with MDI: CBG CV 0.37 vs CV 0.53, respectively, p < 0.001.

CONCLUSIONS/INTERPRETATION

CSII therapy in patients with diabetic gastroparesis results in significant improvement in glycaemic control and reductions in glycaemic variability and number of hospital inpatient bed days.