Functional Electrical Stimulation—A New Therapeutic Approach to Enhance Exercise Intensity in Chronic Obstructive Pulmonary Disease Patients: A Randomized,Controlled Crossover Trial

Objective

To evaluate the effect of quadriceps functional electrical stimulation (FES)-cycling on exertional oxygen uptake ($\dot{\text{V}}$o₂) compared with placebo FES-cycling in patients with chronic obstructive pulmonary disease (COPD).

Six-Minute Walk Test Performance in Persons With Multiple Sclerosis While Using Passive or Powered Ankle-Foot Orthoses

Objective

To determine whether a powered ankle-foot orthosis (AFO) that provides dorsiflexor and plantar flexor assistance at the ankle can improve walking endurance of persons with multiple sclerosis (MS).

The total margin of exposure of ethanol and acetaldehyde for heavy drinkers consuming cider or vodka

Heavy drinkers in Scotland may consume 1600 g ethanol per week. Due to its low price, cider may be preferred over other beverages. Anecdotal evidence has linked cider to specific health hazards beyond other alcoholic beverages. To examine this hypothesis, nine apple and pear cider samples were chemically analysed for constituents and contaminants. None of the products exceeded regulatory or toxicological thresholds, but the regular occurrence of acetaldehyde in cider was detected. To provide a quantitative risk assessment, two collectives of exclusive drinkers of cider and vodka were compared and the intake of acetaldehyde was estimated using probabilistic Monte–Carlo type analysis. The cider consumers were found to ingest more than 200-times the amount of acetaldehyde consumed by vodka consumers. The margins of exposure (MOE) of acetaldehyde were 224 for the cider and over 220,000 for vodka consumers. However, if the effects of ethanol were considered in a cumulative assessment of the combined MOE, the effect of acetaldehyde was minor and the combined MOE for both groups was 0.3. We suggest that alcohol policy priority should be given on reducing ethanol intake by measures such as minimum pricing, rather than to focus on acetaldehyde.     

Acute and subchronic oral toxicity studies in rats with nanoscale and pigment grade titanium dioxide particles

Data generated using standardized testing protocols for toxicity studies generally provide reproducible and reliable results for establishing safe levels and formulating risk assessments. The findings of three OECD guideline-type oral toxicity studies of different duration in rats are summarized in this publication; each study evaluated different titanium dioxide (TiO₂) particles of varying sizes and surface coatings. Moreover, each study finding demonstrated an absence of any TiO₂ -related hazards. To briefly summarize the findings: 1) In a subchronic 90-day study (OECD TG 408), groups of young adult male and female rats were dosed with rutile-type, surface-coated pigment-grade TiO₂ test particles (d₅₀ = 145 nm − 21% nanoparticles by particle number criteria) by oral gavage for 90 days. The no-adverse-effect level (NOAEL) for both male and female rats in this study was 1000 mg/kg bw/day, the highest dose tested. The NOAEL was determined based on a lack of TiO₂ particle-related adverse effects on any in-life, clinical pathology, or anatomic/microscopic pathology parameters; 2) In a 28-day repeated-dose oral toxicity study (OECD TG 407), groups of young adult male rats were administered daily doses of two rutile-type, uncoated, pigment-grade TiO₂ test particles (d₅₀ = 173 nm by number) by daily oral gavage at a dose of 24,000 mg/kg bw/day. There were no adverse effects measured during or following the end of the exposure period; and the NOAEL was determined to be 24,000 mg/kg bw/day; 3) In an acute oral toxicity study (OECD TG 425), female rats were administered a single oral exposure of surface-treated rutile/anatase nanoscale TiO₂ particles (d₅₀ = 73 nm by number) with doses up to 5000 mg/kg and evaluated over a 14-day post-exposure period. Under the conditions of this study, the oral LD₅₀ for the test substance was >5000 mg/kg bw. In summary, the results from these three toxicity studies – each with different TiO₂ particulate-types, demonstrated an absence of adverse toxicological effects. Apart from reporting the findings of these three studies, this publication also focuses on additional critical issues associated with particle and nanotoxicology studies. First, describing the detailed methodology requirements and rigor upon which the standardized OECD 408 guideline subchronic oral toxicity studies are conducted. Moreover, an attempt is made to reconcile the complex issue of particle size distribution as it relates to measurements of nanoscale and pigment-grade TiO₂ particles. Clearly this has been a confusing issue and often misrepresented in the media and the scientific literature. It is clear that the particle-size distribution for pigment-grade TiO₂, contains a small (“tail”) component of nanoscale particles (i.e., 21% by particle number and <1% by weight in the test material used in the 90-day study). However, this robust particle characterization finding should not be confused with mislabeling the test materials as exclusively in the nanoscale range. Moreover, based upon the findings presented herein, there appears to be no significant oral toxicity impact contributed by the nanoscale component of the TiO₂ Test Material sample in the 90-day study. Finally, it seems reasonable to conclude that the study findings should be considered for read-across purposes to food-grade TiO₂ particles (e.g., E171), as the physicochemical characteristics are quite similar.     

Biological effect of food additive titanium dioxide nanoparticles on intestine: an in vitro study

Titanium dioxide nanoparticles (TiO₂ NPs) are widely found in food‐related consumer products. Understanding the effect of TiO₂ NPs on the intestinal barrier and absorption is essential and vital for the safety assessment of orally administrated TiO₂ NPs. In this study, the cytotoxicity and translocation of two native TiO₂ NPs, and these two TiO₂ NPs pretreated with the digestion simulation fluid or bovine serum albumin were investigated in undifferentiated Caco‐2 cells, differentiated Caco‐2 cells and Caco‐2 monolayer. TiO₂ NPs with a concentration less than 200 µg ml^–1 did not induce any toxicity in differentiated cells and Caco‐2 monolayer after 24 h exposure. However, TiO₂ NPs pretreated with digestion simulation fluids at 200 µg ml^–1 inhibited the growth of undifferentiated Caco‐2 cells. Undifferentiated Caco‐2 cells swallowed native TiO₂ NPs easily, but not pretreated NPs, implying the protein coating on NPs impeded the cellular uptake. Compared with undifferentiated cells, differentiated ones possessed much lower uptake ability of these TiO₂ NPs. Similarly, the traverse of TiO₂ NPs through the Caco‐2 monolayer was also negligible. Therefore, we infer the possibility of TiO₂ NPs traversing through the intestine of animal or human after oral intake is quite low. This study provides valuable information for the risk assessment of TiO₂ NPs in food. Copyright © 2015 John Wiley & Sons, Ltd.     

The potential health challenges of TiO2 nanomaterials

Titanium dioxide (TiO₂) nanomaterials (NMs) have found widespread applications owing to their attractive physical and chemical properties. As a result, the potential adverse impacts of nano‐TiO₂ exposure on humans have become a matter of concern. This review presents the state‐of‐the‐art advances on the investigations of the adverse effects of NMs, including the potential exposure routes of nano‐TiO₂ (e.g. respiratory system, skin absorption and digestive system), the physico‐chemical characterizations of nano‐TiO₂ (e.g. crystal structure, shape,size, zeta potential, treatment media, aggregation and agglomeration tendency, surface characteristics and coatings), risk evaluation of nanotoxicity (e.g. cytotoxicity, ecotoxicity, phototoxicity, and phytotoxicity) and potential mechanisms of adverse effects (e.g. generation of reactive oxygen species, oxidative stress and organelle dysfunction). The review aims to facilitate scientific assessments of health risks to nano‐TiO₂, which would guide the safe applications of NMs in our daily life. Copyright © 2015 John Wiley & Sons, Ltd.     

2013年北京市某商场空气质量监测与分析

[目的]了解某大型商场的空气质量状况,分析其变化规律及影响因素. [方法]于2013年对北京市某商场空气质量进行监测,监测点为2个商品售卖区和1个餐饮区,监测指标包括温度、湿度、可吸入颗粒物(PM10)、甲醛、一氧化碳(CO)、二氧化碳(CO2),通过远程数据传输技术收集数据并分析. [结果]监测指标中,CO2合格率(100％)最高;其次是温度、PM10、CO和甲醛,合格率分别为98.82％、96.81％、84.73％、69.41％;湿度合格率最低(仅29.36％).商场内不同季节湿度变化明显(P＜0.05); PM10浓度与室外PM10浓度、客流量存在正相关(r=0.681,r=-0.162;P＜0.05);餐饮区CO和CO2浓度高于其他2个监测点,浓度较高的时段与营业高峰时段一致;甲醛浓度波动较大,甲醛最高浓度达0.214 mg/m3,与商场内湿度呈正相关(r=0.740,P＜ 0.05),不同监测点甲醛浓度差异有统计学意义(P＜0.05).[结论] PM10、CO、甲醛是该商场空气质量的主要危害因素.室外PM10浓度和客流量是影响商场内PM10浓度的主要因素;餐饮活动是CO的主要污染来源,客流量增加引起餐饮活动增多间接影响CO浓度;甲醛污染在商场内持续存在,湿度升高加速甲醛释放,局部装修加剧污染程度.商场应采取集中空调分区域运行,及时调整新风量等措施提高空气质量.     

断乳至性成熟期暴露纳米二氧化硅对小鼠卵巢发育的影响

目的探讨断乳至性成熟期经口持续摄入纳米二氧化硅对小鼠卵巢发育的影响。方法将40只21日龄清洁级ICR雌性小鼠随机分为4组,即对照组和0.25、0.50、1.00 g/kg纳米二氧化硅染毒组,每组10只。采用经口灌胃方式进行染毒,每日1次,持续染毒5周。实验结束后记录小鼠体重增长情况、观察阴门开放时间和动情周期,病理切片计数各级卵泡数量及计算各级卵泡的构成比,并测定卵巢中丙二醛(MDA)含量和超氧化歧化酶(SOD)、谷胱苷肽过氧化物酶(GSH-Px)活力。结果与对照组比较,1.00 g/kg纳米二氧化硅染毒组小鼠卵巢重量和脏器系数下降、阴门开放时间推迟、卵巢黄体构成比下降、闭锁卵泡构成比升高,差异有统计学意义(P0.05);而各剂量纳米二氧化硅染毒组小鼠体重增长和动情周期均无明显改变。与对照组比较,1.00 g/kg纳米二氧化硅染毒组小鼠卵巢组织中MDA含量明显上升,SOD活力均明显下降,而0.50、1.00 g/kg纳米二氧化硅染毒组小鼠卵巢组织中GSH-Px活力均升高,差异具有统计学意义(P0.05)。结论经口摄入纳米二氧化硅可影响小鼠卵巢发育,其机制可能与氧化损伤有关。     

Effectiveness of high-flow nasal cannula on pulmonary rehabilitation in subjects with chronic respiratory failure

BackgroundThe effects of exercise training using both high fraction of inspired oxygen (F_IO₂) and high flow oxygen delivered through a high-flow nasal cannula (HFNC) on exercise capacity in patients with chronic respiratory failure (CRF) receiving long-term oxygen therapy (LTOT) are unknown.MethodsIn this randomized study, 32 patients with CRF receiving LTOT were assigned to undergo 4 weeks of exercise training on a cycle ergometer using an HFNC (flow: 50 L/min) with a F_IO₂ of 1.0 (HFNC group; n = 16) or ordinary supplemental oxygen via a nasal cannula (flow: 6 L/min) (oxygen group; n = 16). A 6-min walking test and a constant-load test were performed before and after 4 weeks of exercise training.ResultsFollowing 4 weeks of exercise training, change in the 6-min walking distance was significantly greater in the HFNC than in the oxygen group (55.2 ± 69.6 m vs. −0.5 ± 87.3 m; p = 0.04). However, there was no significant difference between the two groups in the degree of improvement in the duration of the constant-load exercise test after exercise training.ConclusionsConsidering the effect on daily activities (e.g., walking), exercise training using both high F_IO₂ and high flow through an HFNC is a potentially superior exercise training modality for patients with CRF receiving LTOT.Clinical Trial Registration — http://www.clinicaltrials.gov. Unique identifier: NCT02804243