Follistatin expressed in mechanically-damaged salivary glands of male mice induces proliferation of CD49f(+) cells

Salivary glands (SGs) are very important for maintaining the physiological functions of the mouth. When SGs regenerate and repair from various damages, including mechanical, radiological, and immune diseases, acinar and granular duct cells originate from intercalated duct cells. However, the recovery is often insufficient because of SGs' limited self-repair function. Furthermore, the precise repair mechanism has been unclear. Here, we focused on CD49f, one of the putative stem cell markers, and characterized CD49f positive cells (CD49f(+) cells) isolated from male murine SGs. CD49f(+) cells possess self-renewal ability and express epithelial and pluripotent markers. Compared to CD49f negative cells, freshly isolated CD49f(+) cells highly expressed inhibin beta A and beta B, which are components of activin that has anti-proliferative effects. Notably, an inhibitor of activin, follistatin was expressed in mechanically-damaged SGs, meanwhile no follistatin was expressed in normal SGs in vivo. Moreover, sub-cultured CD49f(+) cells highly expressed both Follistatin and a series of proliferative genes, expressions of which were decreased by Follistatin siRNA. These findings indicated that the molecular interaction between activin and follistatin may induce CD49f(+) cells proliferation in the regeneration and repair of mouse SGs

Non-perturbative dynamics of hot non-Abelian gauge fields: beyond leading log approximation

Many aspects of high-temperature gauge theories, such as the electroweak baryon number violation rate, color conductivity, and the hard gluon damping rate, have previously been understood only at leading logarithmic order (that is, neglecting effects suppressed only by an inverse logarithm of the gauge coupling). We discuss how to systematically go beyond leading logarithmic order in the analysis of physical quantities. Specifically, we extend to next-to-leading-log order (NLLO) the simple leading-log effective theory due to Bodeker that describes non-perturbative color physics in hot non-Abelian plasmas. A suitable scaling analysis is used to show that no new operators enter the effective theory at next-to-leading-log order. However, a NLLO calculation of the color conductivity is required, and we report the resulting value. Our NLLO result for the color conductivity can be trivially combined with previous numerical work by G. Moore to yield a NLLO result for the hot electroweak baryon number violation rate.Comment: 20 pages, 1 figur

Lifetimes of quasiparticles and collective excitations in hot QED plasmas

The perturbative calculation of the lifetime of fermion excitations in a QED plasma at high temperature is plagued with infrared divergences which are not eliminated by the screening corrections. The physical processes responsible for these divergences are the collisions involving the exchange of longwavelength, quasistatic, magnetic photons, which are not screened by plasma effects. The leading divergences can be resummed in a non-perturbative treatement based on a generalization of the Bloch-Nordsieck model at finite temperature. The resulting expression of the fermion propagator is free of infrared problems, and exhibits a {\it non-exponential} damping at large times: $S_R(t)\sim \exp\{-\alpha T t \ln\omega_pt\}$, where $\omega_p=eT/3$ is the plasma frequency and $\alpha=e^2/4\pi$.Comment: LaTex file, 57 pages, 11 eps figures include

Real-time nonequilibrium dynamics in hot QED plasmas: dynamical renormalization group approach

We study the real-time nonequilibrium dynamics in hot QED plasmas implementing a dynamical renormalization group and using the hard thermal loop (HTL) approximation. The focus is on the study of the relaxation of gauge and fermionic mean fields and on the quantum kinetics of the photon and fermion distribution functions. For semihard photons of momentum eT << k << T we find to leading order in the HTL that the gauge mean field relaxes in time with a power law as a result of infrared enhancement of the spectral density near the Landau damping threshold. The dynamical renormalization group reveals the emergence of detailed balance for microscopic time scales larger than 1/k while the rates are still varying with time. The quantum kinetic equation for the photon distribution function allows us to study photon production from a thermalized quark-gluon plasma (QGP) by off-shell effects. We find that for a QGP at temperature T ~ 200 MeV and of lifetime 10 < t < 50 fm/c the hard (k ~ T) photon production from off-shell bremsstrahlung (q -> q \gamma and \bar{q} -> \bar{q}\gamma) at O(\alpha) grows logarithmically in time and is comparable to that produced from on-shell Compton scattering and pair annihilation at O(\alpha \alpha_s). Fermion mean fields relax as e^{-\alpha T t ln(\omega_P t)} with \omega_P=eT/3 the plasma frequency, as a consequence of the emission and absorption of soft magnetic photons. A quantum kinetic equation for hard fermions is obtained directly in real time from a field theoretical approach improved by the dynamical renormalization group. The collision kernel is time-dependent and infrared finite.Comment: RevTeX, 46 pages, including 5 EPS figures, published versio

Dynamical Renormalization Group Approach to Quantum Kinetics in Scalar and Gauge Theories

We derive quantum kinetic equations from a quantum field theory implementing a diagrammatic perturbative expansion improved by a resummation via the dynamical renormalization group. The method begins by obtaining the equation of motion of the distribution function in perturbation theory. The solution of this equation of motion reveals secular terms that grow in time, the dynamical renormalization group resums these secular terms in real time and leads directly to the quantum kinetic equation. We used this method to study the relaxation in a cool gas of pions and sigma mesons in the O(4) chiral linear sigma model. We obtain in relaxation time approximation the pion and sigma meson relaxation rates. We also find that in large momentum limit emission and absorption of massless pions result in threshold infrared divergence in sigma meson relaxation rate and lead to a crossover behavior in relaxation. We then study the relaxation of charged quasiparticles in scalar electrodynamics (SQED). While longitudinal, Debye screened photons lead to purely exponential relaxation, transverse photons, only dynamically screened by Landau damping lead to anomalous relaxation, thus leading to a crossover between two different relaxational regimes. We emphasize that infrared divergent damping rates are indicative of non-exponential relaxation and the dynamical renormalization group reveals the correct relaxation directly in real time. Finally we also show that this method provides a natural framework to interpret and resolve the issue of pinch singularities out of equilibrium and establish a direct correspondence between pinch singularities and secular terms. We argue that this method is particularly well suited to study quantum kinetics and transport in gauge theories.Comment: RevTeX, 40 pages, 4 eps figures, published versio

Transition rate for process involving particles with high momentum in a plasma and infrared physics for QED plasma

We derive a formula for computing the transition rate for a process involving particles with momentum much higher than the temperature and chemical potentials in a plasma by using an effective field theory approach. We apply it to collision of charged particles with hard momentum inside a QED plasma. The Debye screening effect and the damping of a charged particle moving in QED plasma are studied. Using the Bloch-Nordsieck resummation, the infrared divergences due to the absence of magnetic screening for QED plasma are shown not to appear in physically measurable rates. The soft plasmon absorption and emission for charged particles are discussed.Comment: 25 pages, revte

Anomalous Pseudoscalar-Photon Vertex In and Out of Equilibrium

The anomalous pseudoscalar-photon vertex is studied in real time in and out of equilibrium in a constituent quark model. The goal is to understand the in-medium modifications of this vertex, exploring the possibility of enhanced isospin breaking by electromagnetic effects as well as the formation of neutral pion condensates in a rapid chiral phase transition in peripheral, ultrarelativistic heavy-ion collisions. In equilibrium the effective vertex is afflicted by infrared and collinear singularities that require hard thermal loop (HTL) and width corrections of the quark propagator. The resummed effective equilibrium vertex vanishes near the chiral transition in the chiral limit. In a strongly out of equilibrium chiral phase transition we find that the chiral condensate drastically modifies the quark propagators and the effective vertex. The ensuing dynamics for the neutral pion results in a potential enhancement of isospin breaking and the formation of $\pi^0$ condensates. While the anomaly equation and the axial Ward identity are not modified by the medium in or out of equilibrium, the effective real-time pseudoscalar-photon vertex is sensitive to low energy physics.Comment: Revised version to appear in Phys. Rev. D. 42 pages, 4 figures, uses Revte

Outer Membrane Vesicles of Porphyromonas gingivalis Elicit a Mucosal Immune Response

We previously reported that mutation of galE in Porphyromonas gingivalis has pleiotropic effects, including a truncated lipopolysaccharide (LPS) O-antigen and deglycosylation of the outer membrane protein OMP85 homolog. In the present study, further analysis of the galE mutant revealed that it produced little or no outer membrane vesicles (OMVs). Using three mouse antisera raised against whole cells of the P. gingivalis wild type strain, we performed ELISAs to examine the reactivity of these antisera with whole cells of the wild type or the galE mutant. All three antisera had significantly lower reactivity against the galE mutant compared to wild type. OMVs, but not LPS, retained the immunodominant determinant of P. gingivalis, as determined by ELISAs (with wild type LPS or OMVs as antigen) and absorption assays. In addition, we assessed the capacity of OMVs as a vaccine antigen by intranasal immunization to BALB/c mice. Synthetic double-stranded RNA polyriboinosinic polyribocytidylic acid [Poly (I∶C)], an agonist of Toll-like receptor 3 (TLR3), was used as the mucosal adjuvant. Vaccination with OMV elicited dramatically high levels of P. gingivalis-specific IgA in nasal washes and saliva, as well as serum IgG and IgA. In conclusion, the OMVs of P. gingivalis have an important role in mucosal immunogenicity as well as in antigenicity. We propose that P. gingivalis OMV is an intriguing immunogen for development of a periodontal disease vaccine

Periodontal status of rheumatoid arthritis patients in khartoum state

<p>Abstract</p> <p>Background</p> <p>Few studies have investigated the periodontal condition among Rheumatoid arthritis in Sudan. The present study described the periodontal condition among Sudanese patients suffering from rheumatoid arthritis and to compare them with those of non-rheumatic subjects.</p> <p>Methods</p> <p>A group of eighty rheumatoid arthritis patients was selected from Patient's Rheumatoid Clinics in Khartoum State during the period of January to May 2010. A control group of eighty patients with the same age and gender was selected for the study. Both Rheumatoid arthritis patients and the control group were examined for their plaque index, gingival index, and clinical attachment loss.</p> <p>Results</p> <p>The results revealed that there were no significant differences in plaque and gingival index among study and control groups, with mean plaque index of (1.25 ± 0.4) for patients and (1.17 ± 0.28) for the control group (p-value is 0.3597). The mean gingival index was (1.2 ± 0.24) for the patients and (1.2 ± 0.33) for the control (p = is 0.3049). The results showed statistically significant differences in clinical attachment loss between study and control groups, with mean clinical attachment loss of (1.03 ± 0.95) for the study group and (0.56 ± 0.63) for the control group (p = 0.0002). The study revealed that no association exists between the type of drug used to treat rheumatoid arthritis (NSAIDs & DMARDs) and the periodontal parameters (plaque index, gingival index, and clinical attachment loss).</p> <p>Conclusion</p> <p>A significant relationship between periodontal disease and Rheumatoid Arthritis does exist, but no difference between plaque and gingival index has been detected among study and control groups.</p