Gamma interferon induces different keratinocyte cellular patterns of expression of HLA-DR and DQ and intercellular adhesion molecule-I (ICAM-I) antigens

With indirect immunofluorescence techniques we demonstrated that recombinant gamma-interferon induced the expression of the class II antigens HLA-DR and HLA-DQ as well as intercellular adhesion molecule-1 (ICAM-1) on normal, cultured human keratinocytes grown in low-calcium, serum-free medium. Each antigen displayed a distinctive cellular staining pattern. HLA-DR was strongly localized to perinuclear zones with intense cell surface expression; HLA-DQ displayed a perinuclear accentuation, but with minimal cell surface staining, and ICAM-1 was strongly expressed in a diffuse cytoplasmic pattern with intense cell surface expression. Keratinocytes grown in medium supplemented with 10% fetal calf serum underwent differentiation, with a diminished expression of all three antigens as compared to those grown in low-calcium, serum-free medium. These results confirm that gamma interferon can differentially regulate HLA-DR nd HLA-DQ expression; that there are probably different biochemical metabolic pathways by which these three molecules are expressed on keratinocytes, and that the expression is also a function of the degree of keratinocyte differentiation. The strong cell surface expression of ICAM-1 is suggested to be of major importance as the recognition molecule, by which T cells bind to gamma interferon exposed keratinocytes, and suggests and integral role for this molecule in epidermal lymphocyte trafficking.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74686/1/j.1365-2133.1989.tb07759.x.pd

Femtosecond carrier dynamics in bulk graphite and graphene paper

Femtosecond white-light continuum probe transient absorption and reflectivity measurements of bulk graphite and graphene paper are reported. In graphite, the relaxation of photoinduced electron–hole pairs happens through in-plane electron–electron and electron–phonon scattering in similar, equals200 fs, while the ps dynamics is due to the modulation of the electronic structure by out-of-plane structural motions. The ps dynamics of the optical signal is strongly reduced in graphene paper, where the out-of-plane bond is disrupted, while the short component of the dynamics is identical in both materials. These results show that in 2D-graphene, the carrier relaxation occurs in similar, equals200 fs

Blueberry muffin baby: the pathogenesis of cutaneous extramedullary hematopoiesis

Two neonates exhibited the clinical picture of the "blueberry muffin baby" at delivery. The integument manifested petechiae and purpuric magenta-colored macules, papules, and plaques,as well as, blueberry-colored ecchymoses. These findings led to the diagnosis of a connatal cytomegalovirus infection and fetal erythroblastosis, respectively. The hemorrhagic-purpuric looking skin lesions reflected extramedullary hematopoiesis with ultrastructural study disclosing evidence of both erythro- and granulopoietic lineage. For the first time, we were able to demonstrate that complexes of red cells in various stages of maturation can occur in the skin,similarly to, the erythroblastic islands of the bone marrow. In the pathogenesis of extramedullary hematopoiesis, mechanisms underlying the reconstitution of blood cells must be considered. These may reactivate hematopoiesis in organs where it previously occurred in embryonic and fetal life. Possible causative factors may be great compensatory demand, deficient replacement, or loss or dysfunction of corpuscular blood elements. This. would explain the occurrence of this disease entity in conjunction with etiologically completely heterogeneous systemic diseases

MAGNETIC CIRCULAR DICHROISM STUDY OF SPIN-ORBIT SPLITTING IN ALKALI DIMERS IN THE PRESENCE OF A HELIUM SURFACE

G. Aubock, J. Nagl, C. Callegari, and W. E. Ernst, J. Phys. Chem. AV. S. Langford and B. E. Williamson J. Phys. Chem. AAuthor Institution: Institute of Experimental Physics, TU Graz, Petersgasse 16; 8010 Graz, Austria/EUWe present the application of Magnetic Circular Dichroism (MCD) to the determination of the level structure of orbitally-degenerate electronic levels of molecules under the perturbation of a He droplet, which had so far escaped assignment. Our target system is the (1)\,^{3}\Pi_g [(2)\,^{3}\Pi if heteronuclear] manifold of alkali dimers.} \textbf{111,} 7404 (2007).} The perturbation due to the droplet breaks the rotational symmetry around the internuclear axis of the diatom and causes a splitting of this orbitally-degenerate manifold. We extend to He droplets a model previously used to interpret the matrix spectra of the NH radical.} \textbf{2415,} 102 (1998).} With a small number of physically reasonable parameters the model accounts for the essential features of laser-induced fluorescence (LIF) and magnetic circular dichroism (MCD) spectra of \chem{Rb_2} and \chem{K_2}. MCD spectra are not only essential to the correct assignment of the observed structure, but also allow a determination of the populations of Zeeman sublevels in the ground state and thus a measurement of the surface temperature of the droplet. The latter agrees with the accepted temperature, 0.37 K, measured in the interior of a droplet

RELATIVISTIC JAHN-TELLER EFFECTS IN THE QUARTET STATES OF K3_3 AND RB3_{3}: A VIBRATIONAL ANALYSIS OF THE 24^4E′←^{\prime}\leftarrow{}14^4A2′_2^{\prime} ELECTRONIC TRANSITIONS BASED ON AB INITIO CALCULATIONS

Author Institution: Institute of Experimental Physics, Graz; University of Technology, Petersgasse 16, A-8010 Graz, AustriaWe apply the Multireference Rayleigh Schrodinger Perturbation Theory of second order to obtain the adiabatic potential energy surface of the 1$^4$A$_2^{\prime}$ electronic groundstate and the 2$^4$E$^{\prime}$ excited state of K$_3$ and Rb$_3$. Both trimers show a typical E$\times{}$e Jahn-Teller distortion in their 2$^4$E$^{\prime}$ state, which is analyzed in terms of the relativistic Jahn-Teller effect theory. Linear, quadratic as well as spin-orbit coupling terms are extracted from the \emph{ab initio} results and used to obtain theoretical spectra for a direct comparison to laser-induced fluorescence and magnetic circular dichroism spectra of alkali-doped helium nanodroplets [Aubock et al. J. Chem Phys. \textbf{129} 114501 (2008)]

PROGRESS IN OPTICALLY-DETECTED SPIN-RESONANCE ON HELIUM DROPLETS

J. Nagl, G. Aubock, C. Callegari and W. E. Ernst, Phys. Rev. Lett.G. Aubock, J. Nagl, C. Callegari and W. E. Ernst, J. Phys. Chem. AAuthor Institution: Institute of Experimental Physics, TU Graz, Petersgasse 16; 8010 Graz, Austria/EUWe have recently demonstrated the possibility of optically detecting the spin state of alkali metal atoms and molecules formed on helium nanodroplets and immersed in a magnetic field.} \textbf{98,} 075301 (2007).}} \textbf{111,} 7404 (2007).} This has already allowed us to show that the electronic spins of atoms do not relax within the timescale of the experiment ($\sim 10^{-3}$~s) and those of molecules do. With this prerequisites fulfilled, we now set to demonstrate that electron spins on a He droplet can be manipulated. We have already achieved optical pumping, which we intend to present at the meeting, and we strive to soon reach optically-detected electron-spin resonance