ABSTRACT
Research on the deposition of inhaled particles in human pulmonary acinus region is important to the pathogenesis investigation, prevention and treatment of lung diseases. Most of the current research focus on the final deposition fraction of inhaled particles in human acinar region, but little is involved in their dynamic deposition characteristics. In this paper, five multi-alveolar models, G3-G7, were built. The evaluation parameter 1/4 deposition time was introduced to study the particle deposition speed. The deposition characteristics of particles in the diameter ranging 0.1-5 μm were numerically simulated and summarized under the influence of factors such as the generation and structure of model, particle diameter and respiratory mode, shedding some new light on the further research of transport of inhaled particles. The results showed that the generation and structure of model had a significance effect on the deposition of particles. 0.1 μm particles were dominated by Brownian diffusion, which experienced a high deposition fraction, a fast deposition speed and a logarithmic deposition curve, while 5 μm particles were dominated by gravitational sedimentation, with a high deposition fraction, a fast deposition speed and an S-shaped deposition curve. The deposition of 0.3-1 μm particles were influenced greatly by convention and varied with the change of respiratory mode. The research methods and results in this paper can provide theoretical basis and data support for the further exploration of the mechanism, prevention and treatment of lung diseases.
Subject(s)
Humans , Aerosols , Computer Simulation , Lung , Models, Biological , Particle SizeABSTRACT
BACKGROUND: Low-density lipoprotein (LDL) cholesterol has been shown to be a major risk factor for coronary artery disease (CAD) in animal studies, clinical trials, and observational epidemiologic studies. It has a hydrated density of 1.019 to 1.063 kg/L, a diameter of 20 to 30 nm, and displays beta-mobility on paper or agarose gel electrophoresis. With technique such as density gradient ultracentrifugation and gel electrophoresis, it is possible to separate lipoproteins accurately on the basis of their density, charge, and particle size. Further, it has been shown that a smaller LDL is associated with an increased risk of coronary artery disease, even when total cholesterol level is only slightly raised. The aim of this study was to analyze LDL particle size distribution in patients with angiographically confirmed coronary artery disease and in control subjects, using nondenaturating gradient polyacrylamide gel electrophoresis, and to investigate the relationship between LDL particle size and the other traditional coronary risk factors. METHODS: Baseline characteristics such as age, sex, body mass index, history of hypertension or NIDDM, smoking habits, and plasma lipoprotein profiles were obtained in 33 and 27 subjects with and without CAD angiographically confirmed, respectively. We determined LDL peak particle diameter (LDL-PPD) using nondenaturating gradient polyacrylmide gel electrophoresis in CAD and control group. 4% to 12% polyacrylamide gradient gels were used for this assay, and the diameters of LDL subclass peaks were calculated by comparison with a standard calibration curve. This procedure permits the assignment according to distribution of particle diameters as exhibiting pattern A, B, or INT. RESULTS: Traditional coronary risk factors (age, sex, body mass index, history of hypertension or NIDDM, smoking habits, plasma triglyceride, HDL-cholesterol, and total to HDL-cholesterol ratio) were found to be significantly different between two groups, except the plasma total cholesterol and LDL-cholesterol. The mean value of LDL-PPD in patients with CAD was significantly lower than that in control subjects (26.110.4 nm versus 27.011.9 nm, p=0.006). LDL-PPD showed relatively strong associations with plasma triglyceride (r= - 0.536, p<0.01), HDL-cholesterol (r=0.497, p<0.01), and total to HDL-cholesterol ratio (r= - 0.516, p<0.01), but showed no relation to total cholesterol (r= - 0.168) or LDL-cholesterol (r= - 0.028). CONCLUSION: These results suggest an association between small LDL and the presence of CAD and also suggest that LDL-PPD may be associated with the plasma lipid levels.
Subject(s)
Animals , Humans , Body Mass Index , Calibration , Cholesterol , Coronary Artery Disease , Coronary Vessels , Diabetes Mellitus, Type 2 , Electrophoresis , Electrophoresis, Agar Gel , Electrophoresis, Polyacrylamide Gel , Epidemiologic Studies , Gels , Hypertension , Lipoproteins , Particle Size , Plasma , Risk Factors , Smoke , Smoking , Triglycerides , UltracentrifugationABSTRACT
Aim To prepare NT-Ⅰ loaded nanoparticles with different diameters modified by Methylated-polyethyleneglycol (Me-PEG) and evaluate their brain pharmacokinetics after administered nasally in rats. Methods NT-Ⅰ-NP was prepared by emulsion/solvent evaporation method and MePEG-PLA was used as the carrier material. Microdialysis technique and fluorospectrophotometry were used to determine NT-Ⅰ concentration after nasal administration in the brain of rats. Results The appearance of all NT-Ⅰ-NP groups was round or similar. The AUC(0-t) of below 100 nm NT-Ⅰ-NP was 1.22 fold as that of 100~200 nm NT-Ⅰ-NP,1.34 fold as that of 200~300 nm and 1.60 fold as that of exceed 300 nm NT-Ⅰ-NP(P