Mitochondrial effects of dexamethasone imply both membrane and cytosolic-initiated pathways in HepG2 cells

Glucocorticoid treatment is often linked to increased whole-body energy expenditure and hypermetabolism. Glucocorticoids affect mitochondrial energy production, notably in the liver, where they lead to mitochondrial uncoupling reducing the efficacy of oxidative phosphorylation. However, the signaling pathways involved in these phenomena are poorly understood. Here we treated HepG2 cells with dexamethasone for different times and, by using different combinations of inhibitors, we showed that dexamethasone treatment leads to recruitment of two main signaling pathways. The first one involves a G-protein coupled membrane glucocorticoid binding site and rapidly decreases complexes I and II activities while complex III activity is upregulated in a p38MAPK dependent mechanism. The second one implies the classical cytosolic glucocorticoid receptor and triggers long-term transcriptional increases of respiration rates and of complex IV activity and quantity. We concluded that mitochondria are the target of multiple dexamethasone-induced regulatory pathways that are set up gradually after the beginning of hormone exposure and that durably influence mitochondrial oxidative phosphorylation

Period Integrals, Quantum Numbers and Confinement in SUSY QCD

We present a direct computation of the period integrals on degenerate Seiberg-Witten curves for supersymmetric QCD, and show how these periods determine the changes in the quantum numbers of the states, when passing from the weak to the strong-coupling domains in the mass moduli space of the theory. The confinement of monopoles at strong coupling is discussed, and we demonstrate that the ambiguities in choosing the way in the moduli space do not influence to the physical conclusions on confinement of monopoles in the phase with the condensed light dyons.Comment: 16 pages, contribution to special volume on Integrable Systems in Quantum Theor

Mode regularization of the susy sphaleron and kink: zero modes and discrete gauge symmetry

To obtain the one-loop corrections to the mass of a kink by mode regularization, one may take one-half the result for the mass of a widely separated kink-antikink (or sphaleron) system, where the two bosonic zero modes count as two degrees of freedom, but the two fermionic zero modes as only one degree of freedom in the sums over modes. For a single kink, there is one bosonic zero mode degree of freedom, but it is necessary to average over four sets of fermionic boundary conditions in order (i) to preserve the fermionic Z$_2$ gauge invariance $\psi \to -\psi$, (ii) to satisfy the basic principle of mode regularization that the boundary conditions in the trivial and the kink sector should be the same, (iii) in order that the energy stored at the boundaries cancels and (iv) to avoid obtaining a finite, uniformly distributed energy which would violate cluster decomposition. The average number of fermionic zero-energy degrees of freedom in the presence of the kink is then indeed 1/2. For boundary conditions leading to only one fermionic zero-energy solution, the Z$_2$ gauge invariance identifies two seemingly distinct `vacua' as the same physical ground state, and the single fermionic zero-energy solution does not correspond to a degree of freedom. Other boundary conditions lead to two spatially separated $\omega \sim 0$ solutions, corresponding to one (spatially delocalized) degree of freedom. This nonlocality is consistent with the principle of cluster decomposition for correlators of observables.Comment: 32 pages, 5 figure

Higgs Bosons and the Indirect Search for WIMPs

We investigated the contribution of the MSSM Higgs bosons produced in the neutralino annihilation in the Earth and Sun to the total WIMPs detection signals. We found that this contribution is very important and results in a lower bound for the muon flux from the Sun of 10^{-7} - 10^{-8} m^{-2} yr^{-1} for neutralinos heavier than 200 GeV. We noticed that due to the SUSY charged Higgs bosons one can expect an energetic tau neutrino flux from the Sun at a level of 10^2 m^{-2} yr^{-1}.Comment: 10 pages, 4 figures. Talk given at Dark2000, Heidelberg, Germany, 10-15 July, 200

Application of the Large-N_c limit to a Chiral Lagrangian with Resonances

It is shown that the implementation of the Large--$N_c$ approximation helps to get insight into the structure of, in principle, any QCD-like theory. As an example, we will compute the NLO corrections to $L_{10}$ in the chiral limit with a Lagrangian with Resonances.Comment: 9 pages, 1 figure. Talk given at the International School of Subnuclear Physics (Erice 2002). To be published in the Proceeding

On isovector meson exchange currents in the Bethe-Salpeter approach

We investigate the nonrelativistic reduction of the Bethe-Salpeter amplitude for the deuteron electrodisintegration near threshold energies. To this end, two assumptions have been used in the calculations: 1) the static approximation and 2) the one iteration approximation. Within these assumptions it is possible to recover the nonrelativistic result including a systematic extension to relativistic corrections. We find that the so-called pair current term can be constructed from the $P$-wave contribution of the deuteron Bethe-Salpeter amplitude. The form factor that enters into the calculation of the pair current is constrained by the manifestly gauge independent matrix elements.Comment: 15 pages, incl. 3 figures, to be published Phys. Rev.

Spectrometric method to detect exoplanets as another test to verify the invariance of the velocity of light

Hypothetical influences of variability of light velocity due to the parameters of the source of radiation, for the results of spectral measurements of stars to search for exoplanets are considered. Accounting accelerations of stars relative to the barycenter of the star - a planet (the planets) was carried out. The dependence of the velocity of light from the barycentric radial velocity and barycentric radial acceleration component of the star should lead to a substantial increase (up to degree of magnitude) semi-major axes of orbits detected candidate to extrasolar planets. Consequently, the correct comparison of the results of spectral method with results of other well-known modern methods of detecting extrasolar planets can regard the results obtained in this paper as a reliable test for testing the invariance of the velocity of light.Comment: 11 pages, 5 figure

Prostaglandin E2 promotes survival of naive UCB T cells via the Wnt/β-catenin pathway and alters immune reconstitution after UCBT

The outcome of umbilical cord blood transplantation (UCBT) is compromised by low hematopoietic stem cell (HSC) doses leading to prolonged time to engraftment, delayed immunological reconstitution and late memory T-cell skewing. Exposure of UCB to dimethyl-prostaglandin E2 (dmPGE2) increases HSC in vivo. We determined that exposure of UCB T lymphocytes to dmPGE2 modified Wnt signaling resulting in T cell factor (TCF)-mediated transcription. Wnt signaling upregulated interleukin (IL)-7R and IL-2Rβ, resulting in enhanced survival mediated by the homeostatic cytokines IL-7 and IL-15. dmPGE2 also induced components of the Wnt pathway and Wnt receptors, thereby priming UCB T cells to receive signals via Wnt ligands in vivo. We observed that the Wnt transcription factor TCF7 and its target EOMES were elevated in the T cells of patients who received PGE2-treated UCBs. Consistent with the role of Wnt/β-catenin signaling to induce and maintain naive, memory precursors and long-lived central memory CD8+ cells, these patients also had increased fractions of CD8+CD45RO-CD62L+ plus CD8+CD45RO+CD62L+ subsets encompassing these T-cell populations. These effects of the PGE2/Wnt/β-catenin axis may have significant implications for harnessing immunity in the context of UCBT, where impaired immune reconstitution is associated with late memory T-cell skewing

Gluino Condensation in an Interacting Instanton Ensemble

We perform a semi-classical study of chiral symmetry breaking and of the spectrum of the Dirac operator in QCD with adjoint fermions. For this purpose we calculate matrix elements of the adjoint Dirac operator between instanton zero modes and study their symmetry properties. We present simulations of the instanton ensemble for different numbers of Majorana fermions in the adjoint representation. These simulations provide evidence that instantons lead to gluino condensation in supersymmetric gluodynamics.Comment: 32 pages, 5 figures, acknowledgment adde

Domain Wall Junction in N=2 Supersymmetric QED in four dimensions

An exact solution of domain wall junction is obtained in N=2 supersymmetric (SUSY) QED with three massive hypermultiplets. The junction preserves two out of eight SUSY. Both a (magnetic) Fayet-Iliopoulos (FI) term and complex masses for hypermultiplets are needed to obtain the junction solution. There are zero modes corresponding to spontaneously broken translation, SUSY, and U(1). All broken and unbroken SUSY charges are explicitly worked out in the Wess-Zumino gauge in N=1 superfields as well as in components. The relation to models in five dimensions is also clarified.Comment: 27 pages, 6 figures, comments on zero modes added, a few references adde