美托洛尔在慢性阻塞性肺部疾病合并心血管疾病中的疗效观察

目的分析美托洛尔在慢性阻塞性肺部疾病(Chronic obstructive pulmonary disease,COPD)合并心血管疾病的治疗效果,为今后改进治疗策略提供依据。方法将慢性阻塞性肺部疾病合并心血管疾病患者100例随机分为2组,治疗组使用包括美托洛尔辅助的常规治疗方法;对照组为不使用美托洛尔的常规治疗。观察期为半年,随访期间分析心功能分级症状、血压、心率、血氧饱和度以及再次住院率等临床指标变化,评估美托洛尔在治疗COPD并发心血管疾病中的临床安全性和有效性。结果治疗组中患者的心功能分级症状、血压、心率、血氧饱和度、再次住院率等较对照组有明显的改善,同时患者死亡率也明显下降。结论美托洛尔在治疗慢性阻塞性肺部疾病合并心血管疾病中的应用是安全、有效的,可明显改善心脏功能,降低患者再次住院率及死亡率。     

Measurements of the total and regional deposition of inhaled particles in the human respiratory tract

The total and regional deposition of monodisperse aerosols in the human respiratory tract has been measured in 12 healthy subjects breathing through the mouth. Radioactively labelled polystyrene particles in the aerodynamic diameter range 3.5–10.0 μm were employed. The total deposition results are similar to those reported by Stahlhofen et al. (1980), showing only a slight progressive increase with particle size, from a mean fraction of 0.79 of the inhaled aerosol at 3.5 μm, to 0.88 for 10 μm particles. The extrathoracic airways show a very marked deposition at all sizes, predominantly in the throat. The throat values rise rapidly from a mean of 0.09 at 3.5 μm to 0.36 at 10 μm particle diameter. Two intrathoracic fractions were also obtained by the widely accepted method of measuring the relative amounts of activity cleared from the thorax as a function of time. Alveolar deposition was apparently still some 0.06 of the inhaled aerosol at 10 μm particle diameter. Tracheo-bronchial deposition showed little change at any particle size except at 3.5 μm, when it was 0.24 of the inhaled aerosol.     

Particle deposition in the guinea pig respiratory tract

Equations relating particle size of aerosols to deposition by impaction, diffusion and sedimentation are applied to a previously established model of the guinea pig lung using a tidal volume of 4.44 cm³ and a respiratory rate of 60 breath min⁻¹. These calculated deposition values are combined with measured values of nasal deposition to give an estimate of the particle deposition characteristics of the guinea pig respiratory tract. The nasopharyngeal-tracheobronchial (NP-TB) region removes 99% of unit density spherical particle 10 μm or more in diameter. Deposition in this region reaches a minimum of 10% at a particle diameter of 0.8 μm. For particles less than 0.8 μm, deposition increases because of diffusion. Deposition in the pulmonary region is about 17% for particle diameters from 0.08 to 4 μm. For typical polydisperse aerosols with mass median diameters above 1 μm, a greater fraction of the mass than of the count is deposited in the NP-TB region, while a smaller fraction of the mass than of the count is deposited in the pulmonary region. Aerosol clouds with mass median diameters less than 0.1 μm deposit a greater fraction of the count than of the mass in the NP-TB region and a smaller fraction of the count than of the mass in the pulmonary region.     

Mathematical models of particle deposition in the human respiratory tract

Several mathematical formalisms have been proposed to calculate particle transport onto airway surfaces: the temporally and spatially discrete Findeisen formalism; the temporally discrete and spatially continuous Altshuler formalism; and the temporally and spatially continuous Taulbee-Yu formalism; they are termed primary deposition models. Models adopting these formalisms are termed secondary deposition models. This review concentrates on the discussion of the general concepts of primary models and their numerical verification and on characteristics of secondary models. Current deposition models predict particle deposition in close agreement with current experimental data.     

Physical factors determining particle deposition in the human respiratory tract

Total deposition in the human respiratory tract of uncharged, spherical aerosol particles depends on particle diameter, particle density, period of a breathing cycle and respiratory volumetric flow rate. Total deposition of particles larger than 0.5 μm in diameter increases at mouth-breathing with increasing values of these physical factors with the exception that total deposition of particles in the size range between 0.5 and 1 μm is independent of flow rate. These physical factors can be linked by a deposition parameter so that their complex effects on deposition can be described by an unique relationship.     

Experimental determination of particles capture efficiency in flotation

A single bubble experiment is developed for the determination of the capture efficiency by rising bubbles in a uniform concentration of small inertialess glass particles under carefully controlled hydrodynamics and physico-chemical conditions. Air bubbles (0.35-1.3 mm in diameter) rise and reach their terminal velocity in clean water before passing through a suspension of particles (15- in size), where capture takes place. After passing through another zone containing pure water to remove particles trapped in their wake, bubbles release captured particles at the surface from where the particles are collected and counted. A capture efficiency is then calculated as the ratio of the number of particles captured by one rising bubble to the number of particles present in the volume swept out by this bubble. Capture efficiencies range between 10^-3 and 5×10^-1 and are in the order of magnitude of the experimental results presented by Ralston and Dukhin [1999. The interaction between particles and bubbles. Colloids and Surfaces A: Physicochemical and Engineering Aspects 151, 3-14] as well as of numerical results for collision efficiency presented by Sarrot et al. [2005. Determination of the collision frequency between bubbles and particles in flotation. Chemical Engineering Sciene 60 (22), 6107-6117].     

Experimental study on the flow and deposition of powder particles in rotational molding

The nature of powder flow and its effect on particle deposition in rotationally molded parts were considered in this work. Experiments were carried out to observe the effects of various parameters, such as particle characteristics and operating conditions, on the deposition patterns of polyethylene powders and micropellets. The results indicate that the polymeric powders were cohesive enough to prevent size segregation at ambient temperature; however, segregation occurred when particles that had a smooth surface and regular shape were used. During processing, however, a new phenomenon of reverse cohesive segregation was observed. The results showed that the final deposition patterns are controlled primarily by the initial segregation patterns, as well as by the heating rate and rotation speed, which affect the evolution of adhesive forces between particles during heating and melt deposition process. An order‐of‐magnitude analysis was conducted to evaluate the development of cohesive forces between particles, and to estimate their effects on the movement of particles. This study provides a better understanding of the flow characteristics of polymer particles during the rotational molding process, which is very important in the development of techniques for fabricating composites and multilayered products. Polym. Eng. Sci. 45:62–73, 2005. © 2004 Society of Plastics Engineers.     

布地奈德治疗慢性阻塞性肺疾病临床疗效观察

目的观察吸入布地奈德治疗慢性阻塞性肺疾病的效果。方法将80例慢性阻塞性肺疾病患者随机分为两组:对照组40例,给予常规治疗;治疗组40例,给予常规治疗外,给予布地奈德吸入治疗,观察两组治疗前后氧分压(PaO2),二氧化碳分压(PaCO2),FEV1、FVC等指标。结果治疗组的总有效率显著高于对照组,两组疗效比较差异有显著性意义(P<0.01);治疗组的氧分压(PaO2)治疗后显著高于对照组(P<0.05);二氧化碳分压(PaCO2)则显著低于对照组(P<0.05);治疗组的FEV1、FVC治疗后显著高于对照组(P<0.05)。结论应用布地奈德治疗COPD在临床上能显著改善动脉血气指标,值得在临床上推广。     

慢性阻塞性肺疾病患者的全身炎症反应与气道炎症反应的变化及相互关系

目的 探讨急性发作期及缓解期的COPD患者全身炎症反应和气道炎症反应的变化及其相互关系。方法 选取符合COPD诊断标准的患者45例、采用ELISA法分析COPD急性发作期(AECOPD)、缓解期患者诱导痰上清液和外周血清中白介素8(IL-8)和肿瘤坏死因子α(TNF-α)的水平,散射比浊法分析诱导痰上清液和外周血清中C反应蛋白(CRP)水平,并同时测定患者FEV1.0占预计值百分数(FEV1.0pre)。采用SPSS12.0软件进行统计分析。结果 (1)COPD急性发作时外周血清及诱导痰上清液中IL-8、TNF-α和CRP均明显高于缓解期水平(均P<0.01)。(2)痰液及外周血清IL-8、TNF-α、CRP水平与FEV1.0pre呈负相关(均P<0.05)。(3)痰上清液中IL-8和TNF-α与血清中IL-8和TNF-α水平无明显相关(分别为r=0.492,P>0.05;r=0.412,P>0.05),痰上清液中CRP与血清CRP水平明显相关(r=0.864,P<0.01)。结论 (1)COPD急性加重期较缓解期气道局部炎症和全身炎症反应增强,并可能加重了COPD患者的气流阻塞;(2)COPD的全身...     

Effect of octanoic acid-rich formula on plasma ghrelin levels in cachectic patients with chronic respiratory disease

Background  

For cachectic patients with chronic respiratory disease (CRD), conventional enteral nutrition formula is an optional treatment to maintain energy balance. The molecular mechanisms by which enteral nutrition formula controls appetite and weight remain unknown. We examined whether enteral nutrition formula rich in octanoic acids would increase plasma levels of ghrelin, an appetite-stimulating hormone produced in the stomach, in cachectic patients with CRD.     

Experimental study on performance and emissions of a high speed diesel engine fuelled with n-butanol diesel blends under premixed low temperature combustion

In the present paper, results of an experimental investigation carried out in a modern diesel engine running at different operative conditions and fuelled with blends of diesel and n-butanol, are reported. The exploration strategy was focused on the management of the timing and injection pressure to achieve a condition in which the whole amount of fuel was delivered before ignition. The aim of the paper was to evaluate the potential to employ fuel blends having low cetane number and high resistance to auto-ignition to reduce engine out emissions of NOx and smoke without significant penalty on engine performance. Fuel blends were mixed by the baseline diesel (BU00) with 20% and 40% of n-butanol by volume. The n-butanol was taken by commercial production that is largely produced through petrochemical pathways although the molecule is substantially unchanged for butanol produced through biological mechanisms.The experimental activity was performed on a turbocharged, water cooled, DI diesel engine, equipped with a common rail injection system. The engine equipment includes an exhaust gas recirculation system controlled by an external driver, a piezo-quartz pressure transducer to detect the in-cylinder pressure signal and a current probe to acquire the energizing current to the injectors. Engine tests were carried out at 2500 rpm and 0.8 MPa of BMEP exploring the effect of start of injection, O₂ concentration at intake and injection pressure on combustion behavior and engine out emissions. The in-cylinder pressure and rate of heat release were investigated for the neat diesel and the two blends to evaluate engine performance and exhaust emissions both for the conventional diesel and the advanced premixed combustion processes.The management of injection pressure, O₂ concentration at intake and injection timing allowed to realize a partial premixed combustion by extending the ignition delay, particularly for blends. The main results of the investigation made reach smoke and NOx emissions due to the longer ignition delay and a better mixing control before combustion. The joint effect of higher resistance to auto ignition and higher volatility of n-butanol blends improved emissions compared to the neat diesel fuel with a low penalty on fuel consumption.     

Measurement of the human respiratory tract deposited surface area of particles with an electrical low pressure impactor

Abstract

Particle deposition in the human respiratory tract is considered to have negative effects on human health. The lung deposited surface area (LDSA) is an important metric developed to assess the negative health effects of particles deposited in the alveolar region of the human respiratory tract. The measurement of the LDSA is frequently based on the detection of the electrical current carried by diffusion charged particles. Various conversion factors can be used to convert the electric current into LDSA concentration with relatively good accuracy up to the size about 300-600?nm. In this study, we introduce stage-specific LDSA conversion factors for electrical low pressure impactor (ELPI+) data, which enable accurate and real time LDSA concentration and LDSA size distribution measurements in the particle size range from 6?nm to 10?µm. This wide size range covers most of the alveolar deposition of particles, which has not been possible previously by electrical methods. Also, the conversion factors for tracheobronchial and head airways particle surface area deposition were determined, and the stage-specific conversion factors were compared with the single-factor data conversion method. Furthermore, the stage-specific calibration was tested against real-world particle size distributions by simulations and against laboratory-generated aerosols. Particles larger than 300?nm were observed to significantly affect the total LDSA concentration. Stage-specific conversion factors are especially required while measuring aerosols containing larger particles or when considering the surface area deposition in the tracheobronchial region and head airways. The method and the conversion factors introduced in this study can be used to monitor LDSA concentrations reliably in various environments containing particles in different size ranges.

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