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1.
The use of cannabis for medicinal/recreational purposes is widespread throughout the world. Smoke inhalation is known to cause airway irritation due to noxious substances (ie, benzene) within the mix. Thus, advanced vaporisation platforms (eg, Davinci IQ) have been developed to circumvent negative health implications. Here, we consider the impact that cannabis smoke and cannabis vapour have on simulated lung surfactant performance within a model pulmonary space (ie, 37°C, elevated humidity and related fluid hydrodynamics). In total, 50 mg of herbal material was ignited or placed within a Davinci IQ vaporiser with subsequent activation. The aliquots were collected and then analysed using gas chromatography-mass spectroscopy for composition and cannabinoid (eg, Δ9-tetrahydrocannabinol [Δ9-THC]) concentration. The average content within cannabis smoke was 2.84% (0.07%, SD) Δ9-THC, with the same for cannabis vapour being 0.88% (0.14%, SD). Aerosolised samples were transferred to the lung biosimulator. When compared with the pristine Curosurf system, challenge with cannabis smoke and cannabis vapour reduced the surface pressure term by 26% and 7% and increased film compressibility by 60% and 15% at 80% trough area, respectively. The net effect would be enhanced film elasticity and an increased work of breathing, being more pronounced on cannabis smoke inhalation. The trends noted were ascribed to two factors operating synergistically, namely the amount of Δ9-THC (plus others) within the aerosolised samples and the associated toxicity profile. Further research is required to establish mass-balance effects (ie, titrated outputs) along with detailed chemical profiling of material generated from the unrelated cannabis activation pathways.  相似文献   

2.
Deviation in pulmonary surfactant structure–function activity can impair airway patency and lead to respiratory disorders. This novel study aims to evaluate the influence cigarette/e‐cigarette vapour has on model surfactant films located within a simulated pulmonary environment using a lung biosimulator. Chromatographic analysis confirmed that nicotine levels were consistent with the sampling regimen employed. On exposure to smoke vapour, Langmuir isotherms exhibited condensed character and a significant reduction in maximum surface pressure was noted in all cases. Langmuir isocycles, reflective of the human breathing cycle, demonstrated condensed character on smoke vapour delivery. A reduction in the maximum surface pressure was clear only in the case of cigarette vapour application. The components of cigarette vapour can cause oxidative damage to pulmonary surfactant and impair recycling. Neutral nicotine molecules can weaken the structure of the monolayer and cause destabilisation. A protective effect was evident in the case of repeated surfactant compression – relaxation cycles (i.e. the ability to reduce the surface tension term was impaired less), demonstrating a likely innate biological defensive mechanism of the lung. E‐cigarette vapour appeared to have a reduced impact on surfactant performance, which may hold value in harm reduction over the longer term. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

3.
Pulmonary surfactant is an endogenous material that lines and stabilises the alveolar air–liquid interface. Respiratory mechanics can be compromised by exposure to environmental toxins such as cigarette smoke, which contains nicotine. This study aims to determine the influence of nicotine on the activity of simulated lung surfactant at pH 7 and pH 9. In all cases, the addition of nicotine to the test zone caused deviation in surfactant film performance. Importantly, the maximum surface pressure was reduced for each system. Computational modelling was applied to assess key interactions between each species, with the Gaussian 09 software platform used to calculate electrostatic potential surfaces. Modelling data confirmed either nicotine penetration into the two‐dimensional structure or interfacial/electrostatic interactions across the underside. The results obtained from this study suggest that nicotine can impair the ability of pulmonary surfactant to reduce the surface tension term, which can increase the work of breathing. When extrapolated to gross lung function, alveolar collapse and respiratory disease (e.g. chronic airway obstruction) may result. The delivery of nicotine to the (deep) lung can cause a deterioration in lung function and lead to reduced quality of life. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

4.
Interfacial properties of pulmonary surfactant layers   总被引:1,自引:0,他引:1  
The composition of the pulmonary surfactant and the border conditions of normal human breathing are relevant to characterize the interfacial behavior of pulmonary layers. Based on experimental data methods are reviewed to investigate interfacial properties of artificial pulmonary layers and to explain the behavior and interfacial structures of the main components during compression and expansion of the layers observed by epifluorescence and scanning force microscopy. Terms like over-compression, collapse, and formation of the surfactant reservoir are discussed. Consequences for the viscoelastic surface rheological behavior of such layers are elucidated by surface pressure relaxation and harmonic oscillation experiments. Based on a generalized Volmer isotherm the interfacial phase transition is discussed for the hydrophobic surfactant proteins, SP-B and SP-C, as well as for the mixtures of dipalmitoylphosphatidylcholine (DPPC) with these proteins. The behavior of the layers depends on both the oligomerisation state and the secondary structure of the hydrophobic surfactant proteins, which are controlled by the preparation of the proteins. An example for the surface properties of bronchoalveolar porcine lung washings of uninjured, injured, and Curosurf treated lavage is discussed in the light of surface behavior. An outlook summarizes the present knowledge and the main future development in this field of surface science.  相似文献   

5.
Natural lung surfactant contains less than 40% disaturated phospholipids, mainly dipalmitoylphosphatidylcholine (DPPC). The mechanism by which lung surfactant achieves very low near-zero surface tensions, well below its equilibrium value, is not fully understood. To date, the low surface tension of lung surfactant is usually explained by a squeeze-out model which predicts that upon film compression non-DPPC components are gradually excluded from the air-water interface into a surface-associated surfactant reservoir. However, detailed experimental evidence of the squeeze-out within the physiologically relevant high surface pressure range is still lacking. In the present work, we studied four animal-derived clinical surfactant preparations, including Survanta, Curosurf, Infasurf, and BLES. By comparing compression isotherms and lateral structures of these surfactant films obtained by atomic force microscopy within the physiologically relevant high surface pressure range, we have derived an updated squeeze-out model. Our model suggests that the squeeze-out originates from fluid phases of a phase-separated monolayer. The squeeze-out process follows a nucleation-growth model and only occurs within a narrow surface pressure range around the equilibrium spreading pressure of lung surfactant. After the squeeze-out, three-dimensional nuclei stop growing, thereby resulting in a DPPC-enriched interfacial monolayer to reduce the air-water surface tension to very low values.  相似文献   

6.
The dilatational properties, structure, and morphology of the surface films spread at the air–water interface from complex lipid/protein systems were studied by measuring the surface pressure–area and surface potential–area isotherms, the surface rheological properties, and AFM images. The commercially available lung surfactants Alveofact, Curosurf, Survanta, and Exosurf were used as examples.The isotherms of the studied lung surfactant surface films are compared with model lipid and protein monolayers spread from bulk solutions. On the basis of a simple rheological model, the values for the elasticity and the specific time of relaxation related to the reorganization processes occurring in the monolayers were calculated. The spread films of natural surfactants Curosurf and Alveofact show a high effectiveness of spreading and respreading under the conditions of this study. These observations were confirmed by AFM imaging.  相似文献   

7.
Poly(dimethylsiloxane) (PDMS) has a long history of exploitation in a variety of biological and medical applications. Particularly in the past decade, PDMS has attracted interest as a material for the fabrication of microfluidic biochip. The control of cell adhesion on a PDMS surface is important in many microfluidic applications such as cell culture or cell‐based chemicals/drug testing. Unlike many complicated approaches, this study reports simple methods of PDMS surface modification to effectively inhibit or conversely enhance cell adhesion on a PDMS surface using Pluronic surfactant solution and poly‐L ‐lysine, respectively. This research basically succeeded our prior work to further confirm the long‐term capability of 3% Pluronic F68 surfactant to suppress cell adhesion on a PDMS surface over a 6‐day cell culture. Microscopic observation showed that the treated PDMS surface created an unfavorable interface, where chondrocytes seemed to clump together on day 2 and 6 after chondrocyte seeding, and there was no sign of chondrocyte spreading. On the opposite side, results demonstrated that the poly‐L ‐lysine‐treated surface significantly increased fibroblast adhesion by 32% in contrast to the untreated PDMS, which is comparable to the commercial cell‐culture‐grade microplate. However, fibronectin treatment did not have such an effect. All these fundamental information is found useful for any PDMS‐related application. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

8.
Surfactant replacement therapy has a vital role in the management of respiratory distress syndrome (RDS). Several techniques and models have been largely used to investigate interfacial physico-chemical properties in vitro and to assist clinical efficiency of exogenous surfactant preparations (ESPs) in vivo. Among them are interfacial tensiometry (Langmuir balance coupled with Wilhelmy plate method for surface tension measurement) and black foam film (BFF) method for measuring the capability of ESPs for bilayer foam film formation.

Here, we report some freshly established data from a comparative study of Exosurf, Survanta, Curosurf, Alveofact and clinical samples of tracheal aspirate (TA) of newborns with RDS treated with Curosurf. New observations concerning the properties of foam films of ESPs are also reported and discussed.

Measured interfacial physico-chemical parameters prove “better” properties in vitro of the SP-B and -C containing preparations Curosurf and Alveofact. Their properties are similar, Alveofact showing a higher surface tension lowering capacity under dynamic conditions.

A comparison with measured interfacial parameters of clinical samples shows that after treatment with Curosurf the phospholipid concentration in tracheal aspirates (367 μg/ml) is higher than the minimum phospholipid concentration for stable black film formation (Ct) of all four ESPs studied, while before treatment this concentration (63 μg/ml) is lower than Ct.

Values of measured “dynamic” parameters of clinical samples after treatment with Curosurf approach those of the exogenous surfactant preparation itself.  相似文献   


9.
Lung surfactants (LSs) form a monolayer at the lung's alveoli air-solution interface and play a crucial role in making normal breathing possible by reducing the surface tension. LS are affected by various agents that hamper their normal functioning. Tobacco smoke [Bringezu, F.; Pinkerton, K. E.; Zasadzinski, J. A. Langmuir 2003, 19, 2900-2907] and meconium, the first excrement of the newborn, are examples for such LS poison. In neonates, intrauterine aspiration of meconium is a known cause for morbidity and mortality. We studied in vitro the interactions between modified porcine LSs (Curosurf), used as LS replacement, and meconium, as well as between their artificial analogues, phospholipids mixture, and taurocholic acid (TA), respectively. The interactions were examined both in the bulk solution and at the air-water interface, representing the pre- and postnatal situations. It was found that the artificial analogues represent the natural system reliably and exhibit similar effects. TA, a principle component of bile, is an amphiphilic sterol compound in which the hydrophilic and hydrophobic moieties are presented at different faces of the sterol plane. Here we found that TA affects the structure of both monolayers at the interface and surfactant aggregates in solution. A likely poisoning mechanism is by stereoselective penetration of TA into the lamellar or monolayer structures, thus disrupting the contiguous structure of the intact monolayer or the bilayer vesicle structure.  相似文献   

10.
Recently in Canada and some states of the United States, marijuana (cannabis) has become fully legalized and regulated, for both medical and recreational purposes. This fact is going to make cannabis products such as edibles even more popular than ever before. Therefore, it is assumed that there will be a high demand for analytical methods, which are accurate and sensitive enough to be used in different forensic and pharmaceutical cannabis–related applications. Cannabis derivatives have an extreme range and number of constituents with possible interactions with one another. Thus, this characteristic leads to their vast and highly complex chemistry, which requires robust analytical tools to be able to precisely and accurately quantify and qualify them. We developed and validated an analytical method using desorption electrospray ionization (DESI)–mass spectrometry (MS) to accurately detect, characterize, and quantify cannabinoids and also offer an easy, cost‐effective, and reliable technique, which can be performed in a short time for infused edibles in complex matrices such as chocolate. We evaluated a quantitative analysis of tetrahydrocannabinol (THC) in cannabis‐infused chocolate with thin‐layer chromatography (TLC)–DESI‐MS and QuEChERS extraction method. Both techniques of TLC and QuEChERS are cost‐effective and can be run in short time.  相似文献   

11.
Pulmonary surfactant is a mixed lipid protein substance of defined composition that self-assembles at the air-lung interface into a molecular film and thus reduces the interfacial tension to close to zero. A very low surface tension is required for maintaining the alveolar structure. The pulmonary surfactant film is also the first barrier for airborne particles entering the lung upon breathing. We explored by frequency modulation Kelvin probe force microscopy (FM-KPFM) the structure and local electrical surface potential of bovine lipid extract surfactant (BLES) films. BLES is a clinically used surfactant replacement and here served as a realistic model surfactant system. The films were distinguished by a pattern of molecular monolayer areas, separated by patches of lipid bilayer stacks. The stacks were at positive electrical potential with respect to the surrounding monolayer areas. We propose a particular molecular arrangement of the lipids and proteins in the film to explain the topographic and surface potential maps. We also discuss how this locally variable surface potential may influence the retention of charged or polar airborne particles in the lung.  相似文献   

12.
建立了超高效液相色谱-质谱联用(UPLC/PDA-QDa)同时对大麻植物中Δ9-四氢大麻酚(Δ9-THC)、大麻酚(CBN)和大麻二酚(CBD)进行定性与定量分析的方法.缴获的大麻植物用甲醇超声萃取, 采用甲醇(含0.1%甲酸)和超纯水为流动相, 等度洗脱, 流速为0.2 mL/min, 经Waters UPLC BEH C18柱(50 mm×2.1 mm, 1.7 μm)分离, 利用光电二极管阵列检测器(PDA)在220 nm波长下检测, 并通过质谱检测器(QDa)对目标洗脱峰进行追踪确证.在0.5~20 μg/mL浓度范围内, 3种大麻酚类化合物的质量浓度与峰面积呈良好的线性关系, R≥0.999;低、中、高添加水平的平均回收率为82%~102%, 相对标准偏差(RSD)在0.4%~4.1%之间.本方法稳定、简便、灵敏, 能够满足检测需求.根据Δ9-THC、(Δ9-THC+CBN)/CBD、Δ9-THC/CBD或CBN/CBD表型指数, 区分不同产地大麻的化学表型, 为大麻植物的检测分析和质量控制提供了有效手段.  相似文献   

13.
Cannabis sativa is the most frequently used of all illicit drugs in the USA. Cannabis has been used throughout history for its stems in the production of hemp fiber, seed for oil and food, and buds and leaves as a psychoactive drug. Short tandem repeats (STRs) were chosen as molecular markers owing to their distinct advantages over other genetic methods. STRs are codominant, can be standardized such that reproducibility between laboratories can be easily achieved, have a high discrimination power, and can be multiplexed. In this study, six STR markers previously described for C. sativa were multiplexed into one reaction. The multiplex reaction was able to individualize 98 cannabis samples (14 hemp and 84 marijuana, authenticated as originating from 33 of the 50 states of the USA) and detect 29 alleles averaging 4.8 alleles per loci. The data did not relate the samples from the same state to each other. This is the first study to report a single-reaction sixplex and apply it to the analysis of almost 100 cannabis samples of known geographic origin. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

14.
Hemp (Cannabis sativa L.) is a herbaceous anemophilous plant that belongs to the Cannabinaceae family. The cannabis seed (hemp) has long been utilized as a food source and is commercially important as an edible oil source. In this review, the positive and negative health effects of cannabis, the relationship between cannabis and various diseases, and the use of cannabis in various food products have been discussed. In addition, the scientific literature on the potential use of cannabis and its derivatives as a dietary supplement for the prevention and treatment of inflammatory and chronic degenerative diseases in animals and humans has been reviewed. Cannabis is being developed as a key ingredient in a variety of food items, including bakery, confectionery, beverages, dairy, fruits, vegetables, and meat. Hemp seeds are high in readily digestible proteins, lipids, polyunsaturated fatty acids (PUFA), insoluble fiber, carbs, and favorable omega-6 PUFA acid to omega-3 PUFA ratio and have high nutritional value. The antioxidants of cannabis, such as polyphenols, help with anxiety, oxidative stress, and the risk of chronic illnesses, including cancer, neurological disorders, digestive problems, and skin diseases. Cannabis has been shown to have negative health impacts on the respiratory system, driving, and psychomotor functions, and the reproductive system. Overall, the purpose of this research is to stimulate more in-depth research on cannabis’s adaptation in various foods and for the treatment of chronic illnesses.  相似文献   

15.
Drug delivery to the body via the inhaled route is dependent upon patient status, device use, and respirable formulation characteristics. Further to inhalation, drug‐containing particles interact and dissolve within pulmonary fluid leading to the desired pharmacological response. Pulmonary surfactant stabilises the alveolar air‐liquid interface and permits optimal respiratory mechanics. This material represents the initial contacting surface for all inhaled matter. On dissolution, the fate of a drug substance can include receptor activation, membrane partitioning and cellular penetration. Here, we consider the partitioning behaviour of salbutamol when located in proximity to a simulated pulmonary surfactant monolayer at pH 7. The administration of salbutamol to the underside of the surfactant film resulted in an expanded character for the 2‐dimensional ensemble and a decrease in the compressibility term. The rate of drug partitioning was greater when the monolayer was in the expanded state (ie, inhalation end‐point), which was ascribed to more accessible areas for molecular insertion. Quantum mechanics protocols, executed via Gaussian 09, indicated that constructive interactions between salbutamol and integral components of the model surfactant film took the form of electrostatic and hydrophobic associations. The favourable interactions are thought to promote drug insertion into the monolayer structure leading to the observed expanded character. The data presented herein confirm that drug partitioning into pulmonary surfactant monolayers is a likely prospect further to the inhalation of respirable formulations. As such, this process holds potential to reduce drug‐receptor activation and/or increase the residence time of drug within the pulmonary space.  相似文献   

16.
The adsorption free-energy of surfactant on solid surfaces has been calculated by molecular dynamics (MD) simulation for a model surfactant/solvent system. The umbrella-sampling with the weight histogram analysis method (WHAM) was applied. The entropic and enthalpic contributions to the full potential of mean force (PMF) were obtained to evaluate the detailed thermodynamics of surfactant adsorption in solid/liquid interfaces. Although we observed that this surfactant adsorption process is driven mainly by a favorable enthalpy change, a highly unfavorable entropic contribution still existed. By decomposing the free energy (including its entropic and enthalpic components) into the solvent-induced contribution and the surfactant-wall term, the effect of surface and solvent on the adsorption free-energy has been distinguished. The contribution to the PMF from the surface effect is thermodynamically favorable, whereas the solvent term displays an obviously unfavorable component with a monotonic increase as the surfactant approaches to the surface. The impact of various interactions from the surfaces (both solvent-philic and solvent-phobic) and the solvent on the adsorption PMF of surfactant has been compared and discussed. Compared to the solvent-philic surface, the solvent-phobic surface generates more stable site for the surfactant adsorption. However, the full PMF profile for the solvent-phobic system shows a clear positive maximum value at the bulk-interface transition region, which leads to a considerable long-range free-energy barrier to the surfactant adsorption. These results have been analyzed in terms of the local interfacial structures. In summary, this comprehensive study is expected to reveal the microscopic interaction mechanisms determining the surfactant adsorption on solid surfaces.  相似文献   

17.
In this work, a new type of leaf‐shaped cobalt‐zeolitic imidazolate framework–modified graphene (Co‐ZIF‐L@RGO) hybrid was successfully prepared and blended with an intumescent flame retardant (IFR). It was added into thermoplastic polyurethane (TPU) to study the effect of its combination with IFR on the thermal conductivity and flame retardant performance of TPU. The morphology and structure of the Co‐ZIF‐L@RGO hybrid were characterized by scanning electron microscope (SEM), Fourier transform infrared and X‐ray diffraction (XRD). The results showed that Co‐ZIF‐L were uniformly loaded on the surface of graphene. Furthermore, compared with pure TPU, the limiting oxygen index values of the composite material with 3 wt% Co‐ZIF‐L and 27 wt% IFR increased to 32.6%. Their UL‐94 rating reached V‐0 rating. Their peak heat release rate, total heat release, peak smoke production rate and total smoke production were also greatly reduced by 84.4%, 70.1%, 60.3% and 62.5%, respectively. The thermogravimetric‐infrared test results showed that the amount of toxic gas emissions was effectively suppressed. The residual carbon was analyzed by SEM, laser Raman spectroscopy and XRD, and flame retardant mechanism was further investigated. Besides, the addition of this hybrid improved the thermal conductivity of TPU.  相似文献   

18.
Despite high morbidity and mortality associated with lung diseases, addressing drugs towards lung tissue remains a pending task. Particle lung filtration has been proposed for passive lung targeting and drug delivery. However, toxicity issues derived from the long‐term presence of the particles must be overcome. By exploiting some of the ignored properties of nanosized metal–organic frameworks it is possible to achieve impressive antitumoral effects on experimental lung tumors, even without the need to engineer the surface of the material. In fact, it was discovered that, based on unique pH‐responsiveness and reversible aggregation behaviors, nanoMOF was capable of targeting lung tissue. At the neutral pH of the blood, the nanoMOFs form aggregates with the adequate size to be retained in lung capillaries. Within 24 h they then disaggregate and release their drug payload. This phenomenon was compatible with lung tissue physiology.  相似文献   

19.
In acute lung injuries, inactivating agents may interfere with transfer (adsorption) of pulmonary surfactants to the interface between air and the aqueous layer that coats the interior of alveoli. Some ionic and nonionic polymers reduce surfactant inactivation in vitro and in vivo. In this study, we tested directly whether an ionic polymer, hyaluronan, or a nonionic polymer, polyethylene glycol, enhanced adsorption of a surfactant used clinically. We used three different methods of measuring adsorption in vitro: a modified pulsating bubble surfactometer; a King/Clements device; and a spreading trough. In addition we measured the effects of both polymers on surfactant turbidity, using this assay as a nonspecific index of aggregation. We found that both hyaluronan and polyethylene glycol significantly increased the rate and degree of surfactant material adsorbed to the surface in all three assays. Hyaluronan was effective in lower concentrations (20-fold) than polyethylene glycol and, unlike polyethylene glycol, hyaluronan did not increase apparent aggregation of surfactant. Surfactant adsorption in the presence of serum was also enhanced by both polymers regardless of whether hyaluronan or polyethylene glycol was included with serum in the subphase or added to the surfactant applied to the surface. Therefore, endogenous polymers in the alveolar subphase, or exogenous polymers added to surfactant used as therapy, may both be important for reducing inactivation of surfactant that occurs with various lung injuries.  相似文献   

20.
A composite material that comprised metal–organic nanotubes (MONTs) and a sponge, Cu?MONTs?sponge, was synthesized by using a rapid and convenient surfactant‐assisted dip‐coating method and used as a high‐performance adsorbent for the solid‐phase extraction of pharmaceuticals and personal care products (PPCP) from environmental water samples. By adjusting the surfactant concentration, a composite material that contained metal–organic nanotubes and a macroporous 3D porous sponge was constructed. This modified sponge achieved outstanding reproducibility as an adsorbent, with the adsorption of trace or ultratrace amounts of contaminants. Moreover, this composite material was conveniently recycled and its extraction efficiency only decreased by 6.3–12.1 % after 30 adsorption/desorption cycles. The resulting composite exhibited excellent adsorption capacity for PPCPs, which was attributed to its unique porous structure, natural hydrophobicity, and electrostatic interactions between the metal–organic nanotubes and analyte molecules. This Cu?MONTs?sponge material is an ideal adsorbent for the extraction of trace amounts of PPCPs from environmental water samples.  相似文献   

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