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PubMed2002

Mathematical model for diffusion of a protein and a precipitant about a growing protein crystal in microgravity.

Equations are presented that model diffusion of a protein to the surface of a growing crystal in a convection-free environment. The equations apply to crystal growth solutions that contain both a protein and a protein precipitant. The solutions are assumed ternary and the equations include all four diffusion coefficients necessary for the full description of the diffusion process. The four diffusion coefficients are assumed constant. Effects of crystal/solution moving boundary and the effect of a protein adsorption barrier at the crystal interface are included. The equations were applied to the system lysozyme chloride + NaCl + H2O, which has served as the primary model system for the study of crystal growth of proteins and for which there are now published ternary diffusion coefficients. Calculated results with and without the inclusion of cross-term diffusion coefficients are compared.

Chemical Precipitation↗
PubMed2006

A diffusive SI model with Allee effect and application to FIV.

A minimal reaction-diffusion model for the spatiotemporal spread of an infectious disease is considered. The model is motivated by the Feline Immunodeficiency Virus (FIV) which causes AIDS in cat populations. Because the infected period is long compared with the lifespan, the model incorporates the host population growth. Two different types are considered: logistic growth and growth with a strong Allee effect. In the model with logistic growth, the introduced disease propagates in form of a travelling infection wave with a constant asymptotic rate of spread. In the model with Allee effect the spatiotemporal dynamics are more complicated and the disease has considerable impact on the host population spread. Most importantly, there are waves of extinction, which arise when the disease is introduced in the wake of the invading host population. These waves of extinction destabilize locally stable endemic coexistence states. Moreover, spatially restricted epidemics are possible as well as travelling infection pulses that correspond either to fatal epidemics with succeeding host population extinction or to epidemics with recovery of the host population. Generally, the Allee effect induces minimum viable population sizes and critical spatial lengths of the initial distribution. The local stability analysis yields bistability and the phenomenon of transient epidemics within the regime of disease-induced extinction. Sustained oscillations do not exist.

Algorithms↗
PubMed1982

A coupled diffusion and barrier model for the recombination kinetics of myoglobin with carbon monoxide.

The rebinding kinetics of myoglobin (Mb) with carbon monoxide (CO) after photodissociation have been analyzed using a single energy barrier coupled by a two-dimensional channel to the solvent. The total binding rate is written as the product of the barrier rate coefficient and the probability of the ligand being at the barrier. Assuming that the photodissociated ligands are initially localized near the barrier, the probability then decays as 1 t as the ligands migrate away toward the solvent. The time-dependent rate coefficient yields power-law kinetics as observed in the MbCO recombination kinetics. At a given temperature two parameters are sufficient to simulate power-law kinetics of arbitrary slope. Using a model of diffusion from a region of lower to higher diffusivity, four parameters can simulate an initial power law followed by a final slow exponential process. Estimates of the diffusion coefficients inside the protein are two to three orders of magnitude slower than the ligand diffusivity in the external solvent. A single Arrhenius rate coefficient for the barrier can be used for the entire range from 60 K to 320 K. The barrier diffusion model implies a certain shape of the kinetics which is in good agreement with the observed recombination kinetics of many heme protein ligand systems.

Calorimetry↗
PubMed2003

Changes of mGluR4 and the effects of its specific agonist L-AP4 in a rodent model of diffuse brain injury.

OBJECTIVE: Excessive release of glutamate from nerve terminals following diffuse brain injury (DBI) is thought to contribute to neuronal calcium overload leading to calcium-mediated cell damage. Metabotropic glutamate receptor subtype 4 (mGluR4) is regarded as one of the neuroprotective receptors in mammalian brains. Therefore, the mGluR4 specific agonists might exert neuroprotective effects after DBI. The focus of this study is to examine the changes of expression of mGluR4 after DBI and the role of its specific agonist L-AP4 in vivo. METHODS: One hundred and sixty-one male SD rats were randomized into two groups. Group A included normal control, sham-operated control and DBI group. DBI was produced by Marmarou's diffuse head injury model. The mRNA expression of mGluR4 was detected by hybridization in situ. Group B included DBI alone, DBI treated with normal saline and DBI treated with L-AP4. All DBI rats were trained in a series of performance tests, following which they were subjected to DBI. At 1 and 12 h, animals were injected intracerebroventricularly with L-AP4 (100 mM, 10 microl) or normal saline, respectively. The rats were tested for motor and cognitive performance at 1, 3, 7, 14 days post-injury and the damaged neurons were detected. RESULTS: There was no significant difference between the normal control group and sham-operated group in the expression of mGluR4 (P>0.05). The animals exposed to DBI showed a significant increased expression of mRNA of mGluR4 compared with that of the sham-operated animals 1 h after injuries (P<0.05). At 6 h, the evolution of neuronal expression of mGluR4 in the trauma alone group was relatively static. Compared with saline-treated control animals, rats treated with L-AP4 showed decreased number of damaged neurons and a better motor and cognitive performance. CONCLUSIONS: The increased expression of mGluR4 is an important process in the pathophysiological of DBI and its specific agonist L-AP4 can provide a remarkable neuroprotection against DBI not only at the histopathological level but also in the motor and cognitive performance.

Aminobutyrates↗
PubMed2001

A new model for diffuse brain injury by rotational acceleration: I model, gross appearance, and astrocytosis.

Rapid head rotation is a major cause of brain damage in automobile crashes and falls. This report details a new model for rotational acceleration about the center of mass of the rabbit head. This allows the study of brain injury without translational acceleration of the head. Impact from a pneumatic cylinder was transferred to the skull surface to cause a half-sine peak acceleration of 2.1 x 10(5) rad/s2 and 0.96-ms pulse duration. Extensive subarachnoid hemorrhages and small focal bleedings were observed in the brain tissue. A pronounced reactive astrogliosis was found 8-14 days after trauma, both as networks around the focal hemorrhages and more diffusely in several brain regions. Astrocytosis was prominent in the gray matter of the cerebral cortex, layers II-V, and in the granule cell layer and around the axons of the pyramidal neurons in the hippocampus. The nuclei of cranial nerves, such as the hypoglossal and facial nerves, also showed intense astrocytosis. The new model allows study of brain injuries from head rotation in the absence of translational influences.

Acceleration↗
PubMed2002

Prediction of steady-state skin permeabilities of polar and nonpolar permeants across excised pig skin based on measurements of transient diffusion: characterization of hydration effects on the skin porous pathway.

The applicability of a two-parameter Fickian diffusion model for predicting the skin steady-state permeability based on measurements of the transient transport of permeants across the skin was tested. Using five model permeants possessing different physicochemical properties and pig skin as the model membrane, the skin permeabilities predicted by the two-parameter Fickian diffusion model were compared with the measured skin permeabilities. Results show that the transient skin permeation profiles of the hydrophobic permeants, estradiol, testosterone, and dolichol, across split-thickness pig skin can be modeled adequately by the two-parameter Fickian diffusion model (with constant parameter values), and therefore, that this model can be utilized to shorten the experimental time required to determine the skin permeabilities of these compounds. However, the skin permeabilities of the highly hydrophilic permeants, mannitol and sucrose, predicted by the two-parameter Fickian diffusion model (with constant parameter values) were significantly lower than the experimentally determined values, indicating that the dominant skin pathway of polar permeants within the excised pig skin undergoes significant structural changes during the in vitro diffusion cell studies. Although the skin permeability values determined experimentally using the traditional steady-state method normally correspond to a highly hydrated skin sample, the two-parameter Fickian diffusion model enables an estimation of the skin permeability of the skin membrane at its less-hydrated state (a condition more representative of in vivo and clinical situations). Using the two-parameter Fickian diffusion model and a recently developed skin porous-pathway theory, the effects of skin hydration on the skin porous pathway within the excised pig skin were characterized. Specifically, we found that hydration leads to induction of new pores/reduction of the tortuosity of existing pores within the excised pig skin during the 48 h diffusion cell studies conducted, while the skin average pore radii remain relatively constant (approximately 26 A) for up to 48 h.

Algorithms↗
PubMed2005

Synchrotron radiation-induced formation and reactions of free radicals in human acellular dermal matrix.

The present work characterizes the formation of free radicals in an implantable human acellular dermal tissue (Alloderm, LifeCell Corp., Branchburg, NJ) upon irradiation. The tissue was preserved in a vitreous carbohydrate matrix by freeze-drying. Freeze-dried samples were irradiated using a synchrotron light source, and free radicals generated were investigated using the electron paramagnetic resonance (EPR) technique. At least two free radical populations, with g factors of 1.993 (approximately 43%) and 2.002 (approximately 57%), respectively, were identified in the irradiated tissue. The transformation (reaction) kinetics of free radicals produced was investigated in the presence of nitrogen, oxygen and moisture. The reaction kinetics of free radicals was extremely slow in the nitrogen environment. The presence of oxygen and moisture greatly accelerated free radical reactions in the tissue matrix. The reaction of free radicals could not be described by traditional reaction kinetics. A dispersive kinetics model and a diffusion model were developed to analyze the reaction kinetics in the present study. The dispersive model took into consideration molecular mobility and dispersivity of free radicals in the heterogeneous tissue material. The diffusion model described the radical reaction kinetics as two parallel and simultaneous processes: a first-order fast kinetics mainly on tissue surface and a diffusion-limited slow kinetics in deeper layers of the tissue matrix. Both models described quantitative experimental data well. Further investigation is needed to verify whether any of these two models or concepts describes the inherent radical reaction kinetics in the solid tissue matrix.

Calorimetry, Differential Scanning↗
PubMed2006

Capability and limitations of first-order and diffusion approaches to describe long-term sorption of chlortoluron in soil.

This paper compares the capability of a first-order and a spherical diffusion model to describe and predict long-term sorption and desorption processes of chlortoluron in two soils. Chlortoluron sorption was investigated at different time scales utilizing one rate experiment (120 days) and two sorption/desorption experiments. Experimental periods for sorption and desorption were set to 1 day (five desorption steps) and 30 days (three desorption steps), respectively. Upon fitting, the two models satisfactorily described the whole set of data. The spherical diffusion model performed better than the first-order model. We then tested the predictive capability of the models by predicting 30-day sorption/desorption data using kinetic parameters fitted on 1-day sorption/desorption data only. While the spherical diffusion model was able to predict the 30-day data set, the first-order model failed completely. Fitting both models to subsets of the data corresponding to different experimental time scales revealed that the rate parameter as well as the Freundlich coefficient of the first-order model are strongly time-dependent--a property that is not shared by parameters of the spherical diffusion model. The apparent stability of the spherical diffusion model with regard to time dependency of its parameters indicates that sorptive uptake may be diffusion-controlled. This also explains the models greater predictive power across different time scales compared to the first-order model. Finally, we investigate the suitability of solute class specific log-linear relationships between the first-order rate parameter and the Freundlich coefficient presented by earlier researchers in the light of the time dependency observed for the parameters of the first-order model.

Absorption↗
PubMed1995

A diffusion wake model for tracer ultrastructure-permeability studies in microvessels.

We developed a time-dependent diffusion model for analyzing the concentration profiles of low-molecular-weight tracers in the interendothelial clefts of the capillary wall that takes into account the three-dimensional time-dependent filling of the surrounding tissue space. The model provides a connecting link between two methods to investigate transvascular exchange: electron-microscopic experiments to study the time-dependent wake formed by low-molecular-weight tracers (such as lanthanum nitrate) on the tissue side of the junction strand discontinuities in the interendothelial cleft of frog mesentery capillaries (R. H. Adamson and C. C. Michel. J. Physiol. Lond. 466: 303-327, 1993) and confocal-microscopic experiments to measure the spread of low-molecular-weight fluorescent tracers in the tissue space surrounding these microvessels (R. H. Adamson, J. F. Lenz, and F. E. Curry, Microcirculation 1: 251-265, 1994). We show that the interpretation of the presence of tracer as an all-or-none indication of a pathway across the junctional strand is likely to be incorrect for small solutes. Large-pore pathways, in which the local tracer flux densities are high, reach a threshold concentration for detection and are likely to be detected after relatively short perfusion times, whereas distributed small-pore pathways may not be detected until the tissue concentrations surrounding the entire vessel approach threshold concentrations. The analysis using this approach supports the hypothesis advanced by Fu et al. (J. Biomech. Eng. 116: 502-513, 1994) that the principal pathways for water and solutes of < 1.0 nm diameter across the interendothelial cleft may be different and suggests new experiments to test this hypothesis.

Blood Vessels↗
PubMed2002

Application of the diffusion-collision model to the folding of three-helix bundle proteins.

The diffusion-collision model has been successful in explaining many features of protein folding kinetics, particularly for helical proteins. In the model the folding reaction is described in terms of coupled chemical kinetic (Master) equations of coarse grained entities, called microdomains. Here, the diffusion-collision model is applied to compute the folding kinetics of four three-helix bundle proteins, all of which fold on a time scale of tens of microseconds and appear to have two-state folding. The native structure and the stability of the helical microdomains are used to determine the parameters of the model. The formulation allows computation of the overall rate and determination of the importance of kinetic intermediates. The proteins considered are the B domain of protein A (1BDC), the Engrailed Homeodomain (1ENH), the peripheral sub-unit-binding domain (1EBD C-chain) and the villin headpiece subdomain (1VII). The results for the folding time of protein A, the Engrailed Homeodomain, and 1EBD C-chain are in agreement with experiment, while 1VII is not stable in the present model. In the three proteins that are stable, two-state folding is predicted by the diffusion-collision model. This disagrees with published assertions that multistate kinetics would be obtained from the model. The contact order prediction agrees with experiment for protein A, but yields values that are a factor of 40, 30 and 15 too slow for 1ENH, 1EBD C-chain and 1VII. The effect of mutants on folding is described for protein A and it is demonstrated that significant intermediate concentrations (i.e. deviation from two-state folding) can occur if the stability of some of the helical microdomains is increased. A linear relationship between folding time and the length of the loop between helices B and C in protein A is demonstrated; this is not evident in the contact order description.

Amino Acid Sequence↗
PubMed2003

Comparison between the predictions of diffusion-reaction models and localized Ca2+ transients in amphibian skeletal muscle fibers.

We developed a three-dimensional cylindrical diffusion-reaction model of a single amphibian myofibril in which Ca(2+) release occurred only at the Z-line. The model incorporated diffusion of Ca(2+), Mg(2+), and all relevant buffer species, as well as the kinetic binding reactions between the buffers and appropriate ions. Model data was blurred according to a Gaussian approximation of the point spread function of the microscope and directly compared with experimental data obtained using the confocal spot methodology. The flux parameters were adjusted until the simulated Z-line transient matched the experimental one. This model could not simultaneously predict key parameters of the experimental M- and Z-line transients, even when model parameters were adjusted to unreasonably extreme values. Even though the model was accurate in predicting the Z-line transient under conditions of high [EGTA], it predicted a significantly narrower Ca(2+) domain than observed experimentally. We modified the model to incorporate a broader band of release centered at the Z-line. This extended release model was superior both in simultaneously predicting critical features of the Z- and M-line transients as well as the domain profile under conditions of high [EGTA]. We conclude that a model of release occurring exclusively at the Z-line cannot explain our experimental data and suggest that Ca(2+) may be released from a broader region of the sarcoplasmic reticulum than just the T-tubule-sarcoplasmic reticulum junction.

Amphibians↗
PubMed2003

Deviations from the diffusion tensor model as revealed by contour plot visualization using high angular resolution diffusion-weighted imaging (HARDI).

The standard diffusion tensor model is limited in its ability to provide detailed information about multidirectional fiber architecture in human white matter. Additional directional acquisition of diffusivity properties with high angular resolution diffusion-weighted imaging (HARDI) acquisition schemes may deliver more information on areas with fiber crossings than standard DTI. However, representation of the additional information and the rating and visualization of fiber complexity is challenging. We used projection 2D-plots in combination with a HARDI acquisition scheme of 129 diffusion directions and compared the spherical diffusion variance index (SDI) with the relative anisotropy index (RAI). In normal controls, white matter areas with unidirectional fiber arrangement and areas with more complex fiber composition were identified with this approach. HARDI confirms and can visualize deviations from the tensor-like representation, thereby providing information on fiber structure complexity, which may be of considerable interest for clinical studies.

Anisotropy↗
PubMed2026

Non-reciprocal coevolution in a fungus-gardening ant.

Symbioses are often characterized by nonrandom associations between hosts and symbionts. Hosts may obtain symbionts horizontally from the environment or vertically from a parent or sometimes use both methods. Macroevolutionary examinations of fungus-gardening ants and their fungi have shown either a 1:1 coevolution model or a 'diffuse' model between ant host and fungal symbionts. However, some of these conclusions may have been based on using relatively conservative molecular markers, which could obscure cryptic variation. The use of whole genome approaches potentially offer more power in elucidating coevolutionary history. In this study, we examined patterns of coevolution in a single species (Trachymyrmex septentrionalis) using genomic and experimental approaches. We tested whether ant-fungal specificity patterns reflected either 1:1 or diffuse models of coevolution. While we report significant co-phylogenetic signal among intraspecific ant host and fungal symbiont lineages, we found evidence of 1:1 coevolution in some lineages and diffuse in others. These conclusions were supported by the results of experiments where newly mated T. septentrionalis queens were forced to grow novel fungi that suggested that not all fungi are equivalent symbionts and would require specialized hosts. Thus, within a single ant species, there is a mixed support for both models.

Animals↗
PubMed1997

The nitric oxide donor nitroprusside intraperitoneally affects peritoneal permeability in CAPD.

Nitroprusside is a nitric oxide (NO) donor. To investigate effects of nitroprusside i.p. on peritoneal permeability and perfusion, standard peritoneal permeability analyses were performed. Ten stable CAPD patients were studied twice within one week with glucose based dialysate (1.36% Dianeal) with and without addition of nitroprusside 4.5 mg/liter. Mass transfer area coefficients (MTAC) of CO2 were calculated to estimate peritoneal blood flow. Nitrate, a stable metabolite of NO, and cGMP, a second messenger of NO synthesis, were measured in plasma and dialysate. The MTACs of low molecular weight solutes were greater with nitroprusside (NP) compared to the control dwell (C): creatinine median 14.1 (NP) versus 9.9 ml/min (C), urea 21.7 (NP) versus 18.5 ml/min (C) and urate 10.5 (NP) versus 8.6 ml/min (C) (P < 0.05 for all). This points to an increased effective peritoneal surface area with nitroprusside. Furthermore, the restriction coefficient for the low molecular weight solutes decreased from 1.28 (C) to 1.23 (NP) (P = 0.02), suggesting some effect also on the size selectivity to these solutes. The effect of nitroprusside on the clearances of serum proteins was more pronounced. The increase with nitroprusside was 34% for beta 2-microglobulin, 70% for albumin, 77% for IgG and 143% for alpha 2-macroglobulin. This reduction in size selectivity was reflected in a decrease in the restriction coefficient for macromolecules from 2.29 (C) to 1.86 (NP), P < 0.01. This implies an increase in the intrinsic permeability of the peritoneal membrane. Kinetic modeling, using computer simulations, was done to analyze these effects in terms of the pore theory, using a convection model and a diffusion model for the transport of macromolecules. Nitroprusside led to an increase of both the large pore radius and the small pore radius and of the unrestricted area over diffusion distance. These effects were more pronounced with the diffusion model. The MTAC CO2 was not different: NP 76.9 and C 84.1 ml/min. MTACs of nitrate were not greater than expected on the basis of the molecular weight during both dwells. The dialysate/plasma (D/P) ratio of cGMP was greater after addition of nitroprusside: 0.36, range 0.21 to 0.77 (C) and 0.74, 0.23 to 2.50 (NP), P = 0.02. With nitroprusside the D/P ratio of cGMP was greater than expected on the basis of its molecular weight (P < 0.001). This points to local generation of cGMP after the addition of nitroprusside, induced by NO. No differences were found in the dialysate concentrations of the prostaglandins (PG) PGE2 and 6-keto-PGF1 alpha and thromboxane B2 after addition of nitroprusside. The transcapillary ultrafiltration rate and the net ultrafiltration rate during four hours were not different with nitroprusside. In conclusion, nitroprusside i.p. increased the effective peritoneal surface area and the intrinsic permeability, but the peritoneal blood flow did not change. The greater than expected D/P ratios of cGMP point to local generation of cGMP with nitroprusside, induced by NO.

Adult↗
PubMedDate not supplied

[Experimental determination of radiation scattering and absorption coefficients in a homogeneous layer of highly-dispersive biological medium].

A method for experimental determination of optical characteristics of a highly-dispersive medium (radiation scattering and absorption coefficients) is described. The method is based on two mathematical models of ultrashort laser pulse propagation through a highly-dispersive medium (HDM), an axial model and a diffusion model. Milk dissolved in water was used as HDM. Dependences of optical characteristics of HDM on the concentration of milk in water are obtained. The limits of applicability of the axial and diffusion models to media with different scattering and absorption characteristics are determined.

Animals↗
PubMed2003

Impact of metal sorption and internalization on nitrification inhibition.

The goal of this study was to explore the relationship between metal extracellular sorption, intracellular accumulation, and nitrification inhibition. Metal sorption on nitrifying biomass was rapid and could be described by linear partitioning with partition coefficients (Kp) of 20.3 +/- 0.1, 0.4 +/- 0.0, 0.1 +/- 0.0, and 0.2 +/- 0.0 L/g biomass chemical oxygen demand for Cu, Zn, Ni, and Cd, respectively. On the other hand, intracellular Zn, Ni, and Cd concentrations continued to increase with time beyond 12 h after metal addition, whereas intracellular Cu attained equilibrium after 4 h. Metal internalization kinetics could be described by an intraparticle diffusion model, with characteristic diffusion time constants (td) of 9.4, 64.6, 80.5, and 66.1 h for Cu, Zn, Ni, and Cd, respectively. Ultimate internalized percentages of the total cell-associated metal were 1.4 +/- 0.0, 4.3 +/- 0.5,7.6 +/- 1.0, and 2.7 +/- 0.2% for Cu, Zn, Ni, and Cd, respectively. Nitrification inhibition was not a function of the sorbed metal fraction but correlated well with intracellular Zn, Ni, or Cd fractions. An intraparticle diffusion model coupled with a saturation-type biological toxicity model fit the inhibition data for varying initial Cd concentrations and exposure periods. In contrast, no relationship between intracellular or sorbed Cu concentrations and nitrification inhibition was observed. In the presence of 1 mM Cu, less than 13.3 +/- 10.5% cells remained viable as compared to 72.8 +/- 7.5,104.8 +/- 1.7, and 84.7 +/- 7.0% (assumed 100% viable cells in metal-free control) in the presence of 1 mM Zn, Ni, and Cd, respectively. Hence, the observations that inhibition by metals such as Zn, Ni, and Cd is related to their intracellular fraction and the slow kinetics of metal internalization indicate that metal inhibition can easily be underpredicted from short-term batch assays. Furthermore, the inhibitory mechanism of Cu was very different from Zn, Ni, and Cd and may involve rapid loss of membrane integrity.

Adsorption↗
PubMed2004

Changes in metabotropic glutamate receptor 4 expression and the effects of L-2-amino-4-phosphonobutyrate in a rodent model of diffuse brain injury.

OBJECTIVE: To examine the changes in the expression of mGluR4 after diffuse brain injury (DBI) and to determine the role of its specific agonist L-2-amino-4-phosphonobutyrate (L-AP4) in vivo. METHODS: A total of 161 male SD rats were randomized into the following groups. Group A included normal control, sham-operated control and DBI group. DBI was produced according to Marmarou's diffuse head injury model. mRNA expression of mGluR4 was detected by hybridization in situ. Group B included DBI alone, DBI treated with normal saline and DBI treated with L-AP4. All DBI rats were trained in a series of performance tests, following which they were subjected to DBI. At 1 and 12 hours, animals were injected intraventricularly with L-AP4 (100 mmol/L, 10 microl) or normal saline. Motor and cognitive performances were tested at 1, 3, 7, 14 days after injury and the damaged neurons were also detected. RESULTS: There was no significant difference between normal control group and sham-operated group in the expression of mGluR4 (P>0.05). The animals exposed to DBI showed significantly increased expression of mRNA of mGluR4 compared with the sham-operated animals 1 h after injury (P<0.05). At 6 hours, the evolution of neuronal expression of mGluR4 in the trauma alone group was relatively static. Compared with saline-treated control animals, rats treated with L-AP4 showed an effective result of decreased number of damaged neurons and better motor and cognitive performances. CONCLUSIONS: Increased expression of mGluR4 is important in the pathophysiological process of DBI and its specific agonist L-AP4 can provide remarkable neuroprotection against DBI not only at the histopathological level but also in the motor and cognitive performance.

Aminobutyrates↗
PubMed2005

[Experimental study of an animal model of diffuse panbronchiolitis].

OBJECTIVE: To establish an animal model of diffuse panbronchiolitis (DPB) and to investigate the pathogenesis of DPB. METHODS: Sprague-Dawley (SD) rats were intubated with a silicone tube pre-coated with Pseudomonas aeruginosa (P. aeruginosa) in the bronchus. After sixty days, the pathological changes of lung tissue were analyzed. RESULTS: Pathological changes characteristic of DPB were found in the SD rats after the placement of a silicate tube pre-coated with P. aeruginosa in the bronchus. The lung pathology was characterized by diffuse inflammation around bronchi and bronchioles in both lungs, and thickening of the walls of bronchioles with infiltration of lymphocytes, plasma cells, and histiocytes. In addition, bronchus-associated lymphoid tissue (BALT) hyperplasia and accumulation of foamy cells were observed around the bronchi. Thickened walls and enlarged lumen of pulmonary arteries were also noticed occasionally. CONCLUSION: The SD rat model of DPB could be established by infection of P. aeruginosa.

Animals↗