[Study of CD4+ CD25+ regulatory T cells and expression of Foxp3 mRNA in bronchiolitis and glucocorticoid regulation].

OBJECTIVE: To explore the pathogenesis of respiratory syncytial viruses (RSV) bronchiolitis and its treatment with glucocorticoids. METHODS: The pediatric patients with RSV bronchiolitis were divided into an atopic group (n = 50) and a non-atopic group (n = 50) based on whether there were IgE elevation, eczema and dermatitis. Another 25 normal subjects were chosen as a control group. Divided into mild, medium and severe groups, they were finally randomly divided into hormone (dexamethasone) and non-hormone groups. The proportion of CD4+ CD25+ regulatory T cells (Treg) and the expression of Foxp3 mRNA were tested by flow cytometry and RT-PCR retrospectively. RESULTS: The proportion of CD4+ CD25+ Treg and the Foxp3 mRNA expression in the control, non-atopic, and atopic groups reached (10.5 +/- 1.6)% and 0.34 +/- 0.11, (8.8 +/- 2.2)% and 0.26 +/- 0.08, (7.6 +/- 1.8)% and 0.21 +/- 0.09, respectively. There were significant differences among these groups (all P < 0.05). The mild, medium and severe bronchiolitis groups reached (9.7 +/- 1.6)% and 0.28 +/- 0.08, (7.8 +/- 2.1)% and 0.24 +/- 0.06, (6.7 +/- 1.3)% and 0.20 +/- 0.07 respectively (all P < 0.05). The proportion of CD4+ CD25+ Treg and the expression of Foxp3 showed significantly negative correlations with severity (r = -0.62, -0.71, both P < 0.01). That is, they correlated with the severity of disease. The proportion of the CD4+ CD25+ Treg and the expression of Foxp3 mRNA of the hormone group were higher than those of the non-hormone group [(9.5 +/- 2.1)% and 0.33 +/- 0.10 vs (8.5 +/- 1.8)% and 0.27 +/- 0.12, P < 0.05 and < 0.01] respectively. CONCLUSION: CD4+ CD25+ Treg and Foxp3 mRNA are involved in the inflammation of bronchiolitis. And the levels of CD4+ CD25+ Treg and Foxp3 mRNA level is an objective indicator of the severity of RSV bronchiolitis. The effect of glucocorticoids upon RSV bronchiolitis may be in part due to the direct enhancement of production and functions of CD4+ CD25+ Treg and Foxp3 mRNA.

[Relationship of levels of CD4(+)CD25(+) regulatory T cells and expression of Foxp3 mRNA in peripheral blood with serum immunoglobulin E level in children with bronchiolitis].

OBJECTIVE: To study the roles of CD4(+)CD25(+) regulatory T cells and Foxp3 mRNA in peripheral blood as well as serum total immunoglobulin E (IgE) in the pathogenesis of bronchiolitis caused by respiratory syncytial virus (RSV). METHODS: The proportion of CD4(+)CD25(+) regulatory T cells and expression of Foxp3 mRNA in peripheral blood, and total serum IgE level were tested by flow cytometry, RT-PCR and ELISA respectively in 57 children with RSV bronchiolitis (26 atopic patients and 31 nonatopic patients). Twenty five healthy children were used as the control group. RESULTS: The proportion of CD4(+)CD25(+) regulatory T cells in peripheral blood in children with bronchiolitis, either in the atopic (7.7+/- 1.6%)or the nonatopic group (8.8+/- 2.1%), was significantly lower than that in the control group (10.5+/- 1.6%) (P< 0.01). Foxp3 mRNA expression in peripheral blood was significantly lower in both atopic and nonatopic children with bronchiolitis than that in the control group (P< 0.01). Significantly increased total serum IgE level was noted in both atopic (241.2+/- 102.5 IU/mL) and nonatopic children (125.5+/- 63.2 IU/mL) with bronchiolitis compared with that in the control group (27.2+/- 10.5 IU/ml) (P< 0.01). There were significant differences in the proportion of CD4(+)CD25(+) regulatory T cells and Foxp3 mRNA expression in peripheral blood (P< 0.05) as well as total serum IgE level (P< 0.01) between the atopic and the nonatopic group. The proportion of CD4(+)CD25(+) regulatory T cells (r=-0.70, P< 0.01) and Foxp3 mRNA expression in peripheral blood (r=-0.79, P< 0.01) were closely negatively correlated to total serum IgE level. CONCLUSIONS: Both the proportion of CD4(+)CD25(+) regulatory T cells and Foxp3 mRNA expression in peripheral blood were reduced, in contrast, the total serum IgE level increased in children with RSV bronchiolitis. This suggested that CD4(+)CD25(+) regulatory T cells and Foxp3 mRNA together with IgE participated in the pathogenesis of RSV bronchiolitis.

Two-dimensional small-world networks: navigation with local information.

A navigation process is studied on a variant of the Watts-Strogatz small-world network model embedded on a square lattice. With probability , each vertex sends out a long-range link, and the probability of the other end of this link falling on a vertex at lattice distance away decays as r(-a). Vertices on the network have knowledge of only their nearest neighbors. In a navigation process, messages are forwarded to a designated target. For alpha < 3 and alpha not equal to 2, a scaling relation is found between the average actual path length and , where is the average length of the additional long range links. Given pL > 1, a dynamic small world effect is observed, and the behavior of the scaling function at large enough is obtained. At alpha = 2 and 3, this kind of scaling breaks down, and different functions of the average actual path length are obtained. For alpha > 3, the average actual path length is nearly linear with network size.

One-dimensional Ising model built on small-world networks: competing dynamics.

In this paper, we offer a competing dynamic analysis of the one-dimensional Ising model built on the small-world network (SWN). Adding-type SWNs are investigated in detail using a simplified Hamiltonian of mean-field nature, and the result of rewiring-type is given because of the similarities of these two typical networks. We study the dynamical processes with competing Glauber mechanism and Kawasaki mechanism. The Glauber-type single-spin transition mechanism with probability p simulates the contact of the system with a heat bath and the Kawasaki-type dynamics with probability 1-p simulates an external energy flux. By studying the phase diagram obtained in the present work, we can realize some dynamical properties influenced by the small-world effect.

Effect of aging on network structure.

In network evolution, the effect of aging is universal: in scientific collaboration network, scientists have a finite time span of being active; in movie actors network, once popular stars are retiring from stage; devices on the Internet may become outmoded with techniques developing so rapidly. Here we find in citation networks that this effect can be represented by an exponential decay factor, e(-betatau), where tau is the node age, while other evolving networks (the Internet, for instance) may have different types of aging, for example, a power-law decay factor, which is also studied and compared. It has been found that as soon as such a factor is introduced to the Barabasi-Albert scale-free model, the network will be significantly transformed. The network will be clustered even with infinitely large size, and the clustering coefficient varies greatly with the intensity of the aging effect, i.e., it increases linearly with beta for small values of beta and decays exponentially for large values of beta. At the same time, the aging effect may also result in a hierarchical structure and a disassortative degree-degree correlation. Generally the aging effect will increase the average distance between nodes, but the result depends on the type of the decay factor. The network appears like a one-dimensional chain when exponential decay is chosen, but with power-law decay, a transformation process is observed, i.e., from a small-world network to a hypercubic lattice, and to a one-dimensional chain finally. The disparities observed for different choices of the decay factor, in clustering, average node distance, and probably other aspects not yet identified, are believed to bear significant meaning on empirical data acquisition.

Introducing small-world network effects to critical dynamics.

We analytically investigate the kinetic Gaussian model and the one-dimensional kinetic Ising model of two typical small-world networks (SWN), the adding type and the rewiring type. The general approaches and some basic equations are systematically formulated. The rigorous investigation of the Glauber-type kinetic Gaussian model shows the mean-field-like global influence on the dynamic evolution of the individual spins. Accordingly a simplified method is presented and tested, which is believed to be a good choice for the mean-field transition widely (in fact, without exception so far) observed for SWN. It yields the evolving equation of the Kawasaki-type Gaussian model. In the one-dimensional Ising model, the p dependence of the critical point is analytically obtained and the nonexistence of such a threshold p(c), for a finite-temperature transition, is confirmed. The static critical exponents gamma and beta are in accordance with the results of the recent Monte Carlo simulations, and also with the mean-field critical behavior of the system. We also prove that the SWN effect does not change the dynamic critical exponent z=2 for this model. The observed influence of the long-range randomness on the critical point indicates two obviously different hidden mechanisms.

Generalized competing Glauber-type dynamics and Kawasaki-type dynamics.

In this paper, we have given a systematic formulation of a generalized competing mechanism: The Glauber-type single-spin transition mechanism, with probability p, simulates the contact of the system with the heat bath, and the Kawasaki-type spin-pair redistribution mechanism, with probability 1-p, simulates an external energy flux. These two mechanisms are natural generalizations of Glauber's single-spin flipping mechanism and Kawasaki's spin-pair exchange mechanism respectively. On the one hand, the proposed mechanism is, in principle, applicable to arbitrary systems, while on the other hand, our formulation is able to contain a mechanism that just directly combines single-spin flipping and spin-pair exchange in their original form. Compared with the conventional mechanism, the proposed mechanism does not assume the simplified version and leads to a greater influence of temperature. The fact, order for lower temperature and disorder for higher temperature, will be universally true. In order to exemplify this difference, we applied the mechanism to the one-dimensional Ising model and obtained analytical results. We also applied this mechanism to the kinetic Gaussian model and found that above the critical point there will be only paramagnetic phase, while below the critical point, the self-organization as a result of the energy flux will lead the system to an interesting heterophase, instead of the initially guessed antiferromagnetic phase. We studied this process in details.

Kawasaki-type dynamics: diffusion in the kinetic Gaussian model.

In this Brief Report, we retain the basic idea and at the same time generalize Kawasaki's dynamics, the spin-pair exchange mechanism, to a spin-pair redistribution mechanism, and present a normalized redistribution probability. This serves to unite various order-parameter-conserved processes into a universal framework in microscopics and provides the basis for further treatment. As an example of the applications, we treated the kinetic Gaussian model and obtained the exact diffusion equation. We observed critical slowing down near the critical point and found that the critical dynamic exponent z = 1/v = 2 is independent of space dimensionality and the assumed mechanism, whether Glauber type or Kawasaki type.

Driven dynamics: a photodriven Frenkel-Kontorova model.

In this study, we examine the dynamics of a one-dimensional Frenkel-Kontorova chain consisting of nanosize clusters (the "particles") and photochromic molecules (the "bonds"), also being subjected to a periodic substrate potential. Whether the whole chain should be running or be locked depends on both the frequency and the wavelength of the light (keeping the other parameters fixed), as observed through numerical simulation. In the locked state, the particles are bound at the bottom of the external potential and vibrate backwards and forwards at a constant amplitude. In the running state, the initially fed energy is transformed into directed motion as a whole. It is of interest to note that the driving energy is introduced to the system by the irradiation of light, and the driven mechanism is based on the dynamical competition between the inherent lengths of the moving object (the chain) and the supporting carrier (the isotropic surface). However, the most important feature is that the light-induced conformational changes of the chromophore lead to the time-and-space dependence of the rest lengths of the bonds.