IL-7 overexpression in transgenic mouse keratinocytes causes a lymphoproliferative skin disease dominated by intermediate TCR cells: evidence for a hierarchy in IL-7 responsiveness among cutaneous T cells

IL-7 is a keratinocyte-derived lymphocyte growth factor critical for the development of gammadelta T cells including murine dendritic epidermal T cells (DETC). We derived transgenic mice that overexpress IL-7 in basal keratinocytes under the control of the human K14 promoter. These K14/IL-7 mice develop dermal and epidermal T cell infiltrates associated with alopecia. This lymphoproliferative skin disease is substantially more severe in mice homozygous for the K14/IL-7 transgene. Conventional DETC expressing a Vgamma5 Vdelta1 TCR are rare or absent among the cutaneous T cells in these mice. The T cells in the skin infiltrates of young K14/IL-7 mice are predominantly gammadelta T cells that express intermediate levels of TCR, are negative for E-cadherin, often lack expression of CD2, and include cells that coexpress NK1.1. T cells expressing intermediate levels of a TCR-alphabeta are also present in transgenic skin, and progressively increase in number as the mice age. Phenotypically similar intermediate gammadelta and alphabeta T cell subsets also constitute the major lymphocyte populations recovered from organ culture of normal mouse skin in the presence of IL-7, suggesting that the T cells that accumulate in the epidermis of K14/IL-7 mice are derived from precursors normally resident in skin. We conclude that intermediate TCR cells, some of which coexpress NK1.1, can be selectively expanded in skin under the influence of IL-7 produced locally. Our results also suggest that features of the epidermal microenvironment besides keratinocyte-derived IL-7 account for the normal predominance of Vgamma5 Vdelta1 DETC in mouse epidermis.     

Electrochemical properties of Pb–Sb, Pb–Ca–Sn and Pb–Co3O4 anodes in copper electrowinning

Three types of anode, Pb–Sb, Pb–Ca–Sn and Pb–Co₃O₄, for copper electrowinning were investigated. The corrosion resistance, as evaluated by cyclic voltammetric (CV) measurements was higher for Pb–Co₃O₄ than for Pb–Sb and Pb–Ca–Sn. During prolonged electrowinning under galvanostatic conditions, the anodic reaction on the Pb–Co₃O₄ anode was depolarized by 0.053 V as compared to Pb–Sb, and by 0.106 V with respect to Pb–Ca–Sn. The composition and structure of the anodic layer were determined by XPS, X-ray and SEM analyses. The surface layer on the three anodes examined was composed mainly of PbSO₄, -PbO₂ and -PbO₂. Different structure of the surface layer was observed: loose and highly spread coral-like structure in the case of Pb–Sb; fibrous structure in the case of Pb–Ca–Sn and dense, fine-grained structure in the case of Pb–Co₃O₄.     

Predicting the preferable range of the total concentrations of metal ions in solutions for alloy electrodeposition

Based on statistical and regression analysis of information on the composition of solutions for the electrodeposition of A-B alloys, a mathematical model is proposed that allows the preferable range of the total concentrations of the ions of metals in solutions for alloy electrodeposition to be predicted. Original Russian Text ? E.G. Vinokurov, T.F. Burukhina, M.N. Karanaeva, V.V. Bondar’, 2008, published in Teoreticheskie Osnovy Khimicheskoi Tekhnologii, 2008, Vol. 42, No. 6, pp. 671–676.     

Structural Features and Tribological Properties of Multilayer Coatings Based on Refractory Metals

A comparative analysis of the structural features and tribological properties of multilayer coatings based on refractory metal compounds has been conducted in this review. Features of formation of the electronic structure of the synthesized coatings have been discussed, and the effect of methods and conditions of deposition on changes in the physicomechanical characteristics of nanocrystalline structures based on transition metal nitrides has been shown. Dependences of antifriction properties, corrosion resistance, and thermal stability on the modulation period (Λ) and the number of bilayers in the studied multilayer coatings have been determined. A decrease in the modulation period of individual layers in a coating positively affects the oxidation resistance of the coating, while an increase in the number of interfaces between the layers slows down the diffusion of oxygen atoms deep into the coating and, thereby, increases the protective properties of the multilayer system as a whole. The effect of the droplet component in cathodic-arc coatings on corrosion development mechanisms in corrosive media has been shown. A class of multifunctional multilayer coatings with an adaptive friction mechanism, which is characterized by a change in the properties and structure during tribological tests, has been discussed separately.     

Phase equilibria at the solidus surface of the equilibrium diagram of ternary systems of technetium with carbon and d-transition metals of groups III–VII

Translated from Poroshkovaya Metallurgiya, No. 11(323), pp. 46–52, November, 1989.     

Mutant PCNA alleles are associated with cdc phenotypes and sensitivity to DNA damage in fission yeast

Twenty-eight site-directed mutations were introduced into the fission yeast gene (pcn1+) that encodes proliferating cell nuclear antigen (PCNA) and their in vivo effects analyzed in a strain with a null pcn1 background. Mutants defective in enhancing processivity of DNA polymerase delta have previously been identified. In this study, we assessed all of the mutants for their sensitivities to temperature, hydroxyurea, UV irradiation and methyl methanesulfonate (MMS), and specific mutants were also tested for sensitivity to gamma irradiation. One cold-sensitive allele, pcn1-3, was characterized in detail. This mutant had a recessive cold-sensitive cdc phenotype and showed sensitivity to hydroxyurea, UV, and gamma irradiation. At the non-permissive temperature pcn1-3 protein was able to form homotrimers in solution and showed increased stimulation of both synthetic activity and processivity of DNA polymerase delta relative to the wild-type Pcn1+ protein. Epistasis analyses indicated that pcn1-3 is defective in the repair pathway involving rad2+ but not defective in the classical nucleotide excision repair pathway involving rad13+. Furthermore, pcn1-3 is either synthetically or conditionally lethal in null checkpoint rad backgrounds and displays a mitotic catastrophe phenotype in these backgrounds. A model for how pcn1-3 defects may affect DNA repair and replication is presented.