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Understanding how molecules can restructure the surfaces of heterogeneous catalysts under reaction conditions requires methods that can visualize atoms in real space and time. We applied a newly developed aberration-corrected environmental transmission electron microscopy to show that adsorbed carbon monoxide (CO) molecules caused the {100} facets of a gold nanoparticle to reconstruct during CO oxidation at room temperature. The CO molecules adsorbed at the on-top sites of gold atoms in the reconstructed surface, and the energetic favorability of this reconstructed structure was confirmed by ab initio calculations and image simulations. This atomic-scale visualizing method can be applied to help elucidate reaction mechanisms in heterogeneous catalysis.

It is crucial to understand the nature of CO adsorption on gold so as to elucidate the mechanism of low-temperature CO oxidation on nanogold catalysts. We performed theoretical analysis of CO adsorption on gold by using Hückel theory and density functional theory (DFT) calculations. Hückel theory indicates that CO adsorption on gold is dominated by the electron distribution at the Au atom, which is greatly affected by neighboring Au atoms, coadsorbed or doping species. The increase of σ-bonding electrons should weaken the CO adsorption, while the increase of π-electrons should strengthen the adsorption. DFT calculations proved this prediction quantitatively for various systems, including CO adsorption on a Au(100)-hex surface with locally varying subsurface configurations and CO coadsorption with acceptor or donor species., (Copyright © 2011 Wiley Periodicals, Inc.)

The transcription factor BATF controls the differentiation of interleukin 17 (IL-17)-producing helper T cells (T(H)17 cells) by regulating expression of the transcription factor RORγt itself and RORγt target genes such as Il17. Here we report the mechanism by which BATF controls in vivo class-switch recombination (CSR). In T cells, BATF directly controlled expression of the transcription factors Bcl-6 and c-Maf, both of which are needed for development of follicular helper T cells (T(FH) cells). Restoring T(FH) cell activity to Batf(-/-) T cells in vivo required coexpression of Bcl-6 and c-Maf. In B cells, BATF directly controlled the expression of both activation-induced cytidine deaminase (AID) and of germline transcripts of the intervening heavy-chain region and constant heavy-chain region (I(H)-C(H)). Thus, BATF functions at multiple hierarchical levels in two cell types to globally regulate switched antibody responses in vivo.

Ultrasound spectroscopy is a powerful tool to investigate the viscoelastic properties of materials. The longitudinal elastic moduli M' and M(″), or the adiabatic compressibility κ(S) can be evaluated from ultrasound velocity v and attenuation coefficient α via the relation M'=ρv(2) and M(″)=2ραv(3)/ω, where ρ is the density and ω is the angular frequency. So far, the density was independently measured by other equipments or its variation during the chemical reaction has been ignored in the previous literatures. Here we propose a multiple echo method to simultaneously evaluate α, v, ρ, from a single acquisition, enabling us to monitor the polymerization process of acrylamide, where the three parameters vary independently during the reaction. This allows us to analyze the time evolution of the acoustic parameters for polymeric or gelling systems with the better understanding., (Copyright © 2010 Elsevier B.V. All rights reserved.)

We previously described two unrelated patients showing characteristic facial and skeletal features, overlapping with the kyphoscoliosis type Ehlers-Danlos syndrome (EDS) but without lysyl hydroxylase deficiency [Kosho et al. (2005) Am J Med Genet Part A 138A:282-287]. After observations of them over time and encounter with four additional unrelated patients, we have concluded that they represent a new clinically recognizable type of EDS with distinct craniofacial characteristics, multiple congenital contractures, progressive joint and skin laxity, and multisystem fragility-related manifestations. The patients exhibited strikingly similar features according to their age: craniofacial, large fontanelle, hypertelorism, short and downslanting palpebral fissures, blue sclerae, short nose with hypoplastic columella, low-set and rotated ears, high palate, long philtrum, thin vermilion of the upper lip, small mouth, and micro-retrognathia in infancy; slender and asymmetric face with protruding jaw from adolescence; skeletal, congenital contractures of fingers, wrists, and hips, and talipes equinovarus with anomalous insertions of flexor muscles; progressive joint laxity with recurrent dislocations; slender and/or cylindrical fingers and progressive talipes valgus and cavum or planus, with diaphyseal narrowing of phalanges, metacarpals, and metatarsals; pectus deformities; scoliosis or kyphoscoliosis with decreased physiological curvatures of thoracic spines and tall vertebrae; cutaneous, progressive hyperextensibility, bruisability, and fragility with atrophic scars; fine palmar creases in childhood to acrogeria-like prominent wrinkles in adulthood, recurrent subcutaneous infections with fistula formation; cardiovascular, cardiac valve abnormalities, recurrent large subcutaneous hematomas from childhood; gastrointestinal, constipation, diverticula perforation; respiratory, (hemo)pneumothorax; and ophthalmological, strabismus, glaucoma, refractive errors., ((c) 2010 Wiley-Liss, Inc.)

Although CD103-expressing dendritic cells (DCs) are widely present in nonlymphoid tissues, the transcription factors controlling their development and their relationship to other DC subsets remain unclear. Mice lacking the transcription factor Batf3 have a defect in the development of CD8alpha+ conventional DCs (cDCs) within lymphoid tissues. We demonstrate that Batf3(-/-) mice also lack CD103+CD11b- DCs in the lung, intestine, mesenteric lymph nodes (MLNs), dermis, and skin-draining lymph nodes. Notably, Batf3(-/-) mice displayed reduced priming of CD8 T cells after pulmonary Sendai virus infection, with increased pulmonary inflammation. In the MLNs and intestine, Batf3 deficiency resulted in the specific lack of CD103+CD11b- DCs, with the population of CD103+CD11b+ DCs remaining intact. Batf3(-/-) mice showed no evidence of spontaneous gastrointestinal inflammation and had a normal contact hypersensitivity (CHS) response, despite previous suggestions that CD103+ DCs were required for immune homeostasis in the gut and CHS. The relationship between CD8alpha+ cDCs and nonlymphoid CD103+ DCs implied by their shared dependence on Batf3 was further supported by similar patterns of gene expression and their shared developmental dependence on the transcription factor Irf8. These data provide evidence for a developmental relationship between lymphoid organ-resident CD8alpha+ cDCs and nonlymphoid CD103+ DCs.

The inhibitory immunoregulatory receptor CTLA-4 is critical in maintaining self-tolerance, but the mechanisms of its actions have remained controversial. Here we examined the antigen specificity of tissue-infiltrating CD4(+) T cells in Ctla4(-/-) mice. After adoptive transfer, T cells isolated from tissues of Ctla4(-/-) mice showed T cell antigen receptor (TCR)-dependent accumulation in the tissues from which they were derived, which suggested reactivity to tissue-specific antigens. We identified the pancreas-specific enzyme PDIA2 as an autoantigen in Ctla4(-/-) mice. CTLA-4 expressed either on PDIA2-specific effector cells or on regulatory T cells was sufficient to control tissue destruction mediated by PDIA2-specific T cells. Our results demonstrate that both cell-intrinsic and non-cell-autonomous actions of CTLA-4 operate to maintain T cell tolerance to a self antigen.

We examined the atomic and electronic structures of an interface between a 1-ethyl-3-methyl imidazolium tetrafluoroborate (EMIM-BF(4)) ionic-liquid crystal and a Li(100) surface by periodic density-functional calculations, as a model for a room-temperature ionic-liquid (RTIL) electrolyte/Li interface at a Li-ion battery electrode. Results are compared with our previous theoretical study of the EMIM-BF(4) molecular adsorption on Li surfaces [H. Valencia et al., Phys. Rev. B 78, 205402 (2008)]. For the EMIM-BF(4) crystal structure, the present projector augmented wave scheme with the generalized gradient approximation can reproduce rather correct intramolecular structures as well as satisfactory short-ranged intermolecular distances, while long-range intermolecular distances are overestimated due to the lack of correct description of long-range dispersive interactions. We constructed a coherent crystal/crystal interface model where four EMIM-BF(4) pairs are stacked on a p(4x3) Li (100) surface cell so as to simulate RTIL-layer deposition on a Li surface. We observed significant attraction of surface Li ions toward contacting BF(4)(-) anions, counterbalanced by electron transfer toward EMIM(+) cations near the interface, revealing the tendency of easy ionization of Li and Li(x)-BF(4) cluster formation, coupled with the reduction of EMIM(+). These features are similar to those observed in the EMIM-BF(4) molecular adsorption, while these have been proved to occur in the crystal-layer adsorption. We examined the adhesive energy, wetability, and detailed electronic structure at the crystal/crystal interface.

Graphene nanosheet (GNS) gives rise to an extraordinary modification to the properties of Pt cluster electrocatalysts supported on it. The Pt/GNS electrocatalyst revealed an unusually high activity for methanol oxidation reaction compared to Pt/carbon black catalyst. The Pt/GNS electrocatalyst also revealed quite a different characteristic for CO oxidation among the measured catalyst samples. It is found that Pt particles below 0.5 nm in size are formed on GNS, which would acquire the specific electronic structures of Pt, modifying its catalytic activities.

We perform first-principles computational tensile and compressive tests (FPCTT and FPCCT) to investigate the intrinsic bonding and mechanical properties of a γ-TiAl intermetallic compound (L 1(0) structure) using a first-principles total energy method. We found that the stress-strain relations and the corresponding theoretical tensile strengths exhibit strong anisotropy in the [001], [100] and [110] crystalline directions, originating from the structural anisotropy of γ-TiAl. Thus, γ-TiAl is a representative intermetallic compound that includes three totally different stress-strain modes. We demonstrate that all the structure transitions in the FPCTT and FPCCT result from the breakage or formation of bonds, and this can be generalized to all the structural transitions. Furthermore, based on the calculations we qualitatively show that the Ti-Al bond should be stronger than the Ti-Ti bond in γ-TiAl. Our results provide a useful reference for understanding the intrinsic bonding and mechanical properties of γ-TiAl as a high-temperature structural material.

Laser-ablated gold atoms have been codeposited at 4 K with nitric oxide in excess argon and the low temperature reactions of Au with NO in solid argon have been studied using infrared spectroscopy. The reaction products Au(2)NO(-), Au(2)NO, Au(3)NO, Au(4)NO, and Au(5)NO are formed in the present experiments and characterized on the basis of isotopic shifts, mixed isotope splitting patterns, stepwise annealing, the change in reagent concentration and laser energy, and comparison with theoretical predictions. Density functional theory calculations have been performed on these systems to identify possible reaction products. The agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts supports the identification of these molecules based on the matrix infrared spectra. Plausible reaction pathways have been proposed for the formation of these molecules.

Tissue macrophages comprise a heterogeneous group of cell types differing in location, surface markers and function. Red pulp macrophages are a distinct splenic subset involved in removing senescent red blood cells. Transcription factors such as PU.1 (also known as Sfpi1) and C/EBPalpha (Cebpa) have general roles in myelomonocytic development, but the transcriptional basis for producing tissue macrophage subsets remains unknown. Here we show that Spi-C (encoded by Spic), a PU.1-related transcription factor, selectively controls the development of red pulp macrophages. Spi-C is highly expressed in red pulp macrophages, but not monocytes, dendritic cells or other tissue macrophages. Spic(-/-) mice have a cell-autonomous defect in the development of red pulp macrophages that is corrected by retroviral Spi-C expression in bone marrow cells, but have normal monocyte and other macrophage subsets. Red pulp macrophages highly express genes involved in capturing circulating haemoglobin and in iron regulation. Spic(-/-) mice show normal trapping of red blood cells in the spleen, but fail to phagocytose these red blood cells efficiently, and develop an iron overload localized selectively to splenic red pulp. Thus, Spi-C controls development of red pulp macrophages required for red blood cell recycling and iron homeostasis.

Purpose: To evaluate whether the pouchitis disease activity index (PDAI) alone is sufficient to select appropriate treatment plans for ulcerative colitis patients with bowel movement problems following ileal pouch-anal anastomosis (IPAA)., Methods: The study included 70 patients undergoing an IPAA. For these patients, an evaluation by PDAI was performed prospectively at 1-2 years after the ileostomy closure. When the symptoms relevant to bowel movement appeared, PDAI was evaluated and metronidazole or ciprofloxacin was administered. Pouchitis was diagnosed in patients with PDAI scores of 7 or higher. The patients whose PDAI score was less than 7 and who responded to antibiotic therapy were defined as treatment responders having disease not diagnosed by PDAI (TR-NDPDAI)., Results: Pouchitis was diagnosed in 16 of the 70 enrolled patients (22.9%) using the PDAI scoring system. Of these 16 patients, 11 had acute pouchitis and 5 had chronic pouchitis. Twenty-one patients whose PDAI score was less than 7 were symptomatic. Among them, 12 were TR-NDPDAI. In patients with TR-NDPDAI, antibiotic treatment resulted in significant improvements in the PDAI score (P < 0.001) and in clinical symptoms (P < 0.001) after treatment., Conclusion: Antibiotic treatment was effective in a considerable number of ulcerative colitis patients whose PDAI score was less than 7 after IPAA.

Reactions of laser-ablated Au atoms with N(2)O molecules in excess argon have been investigated using matrix-isolation infrared spectroscopy and density functional theory calculation. On the basis of isotopic shifts, mixed isotopic splitting patterns, CCl(4)-doping experiments, and the comparison with theoretical calculations, the absorption at 2047.5 cm(-1) is assigned to the OAuNN(-) anion, and the absorption at 1512.3 cm(-1) is assigned to the AuNO(-) anion, respectively. No evidence is found for the formation of new neutral and cationic products in the present experiments. It is predicted that the OAuNN(-) anion is a linear singlet molecule and the AuNO(-) anion is a bent doublet molecule. The agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts supports the identifications of these species from the matrix infrared spectra. Plausible reaction pathways have also been discussed for the formation of these products.

Although in vitro observations suggest that cross-presentation of antigens is mediated primarily by CD8alpha+ dendritic cells, in vivo analysis has been hampered by the lack of systems that selectively eliminate this cell lineage. We show that deletion of the transcription factor Batf3 ablated development of CD8alpha+ dendritic cells, allowing us to examine their role in immunity in vivo. Dendritic cells from Batf3-/- mice were defective in cross-presentation, and Batf3-/- mice lacked virus-specific CD8+ T cell responses to West Nile virus. Importantly, rejection of highly immunogenic syngeneic tumors was impaired in Batf3-/- mice. These results suggest an important role for CD8alpha+ dendritic cells and cross-presentation in responses to viruses and in tumor rejection.

Density functional theory calculations are carried out to study CO adsorption on the (001) surface of a LaNi(5) hydrogen storage alloy. At low coverages, CO favors adsorption on Ni-Ni bridge sites. With an increase in CO coverage, the decrease in the adsorption energy is much larger for Ni-Ni-CO bridge adsorption than that for Ni-CO on-top adsorption. Thus, the latter sites in the relatively stable adsorption structure are preferentially utilized at high CO coverages. The nature of the bonding between CO and the LaNi(5) (001) surface is analyzed in detail.

Calcineurin is required for B cell receptor (BCR)-induced proliferation of mature B cells. Paradoxically, loss of NFAT transcription factors, themselves calcineurin targets, induces hyperactivity, which suggests that calcineurin targets other than NFAT are required for BCR-induced proliferation. Here we demonstrate a function for the calcineurin-regulated transcription factor Mef2c in B cells. BCR-induced calcium mobilization was intact after Mef2c deletion, but loss of Mef2c caused defects in B cell proliferation and survival after BCR stimulation in vitro and lower T cell-dependent antibody responses and germinal center formation in vivo. Mef2c activity was specific to BCR stimulation, as Toll-like receptor and CD40 signaling induced normal responses in Mef2c-deficient B cells. Mef2c-dependent targets included the genes encoding cyclin D2 and the prosurvival factor Bcl-x(L). Our results emphasize an unrecognized but critical function for Mef2c in BCR signaling.

During T cell development in the thymus, a certain population of self-reactive thymocytes differentiates into regulatory T cells that suppress otherwise harmful self-reactive T cells. In transgenic mice expressing both TCR that specifically recognizes moth cytochrome c and the moth cytochrome c ligand, a large proportion of CD4+ T cells expresses CD25 and secretes TGF-beta1 upon Ag stimulation. Because TGF-beta1 expression by these T cells can be decreased by cyclosporin A, a NF-AT inhibitor, NF-AT-mediated TGF-beta1 expression in T cells was addressed by characterizing a NF-AT response element in the TGF-beta1 promoter. Analysis of the mouse TGF-beta1 promoter (-1799 to +793) in transfection experiments in T cell 68-41 hybridoma cells detected NF-AT binding sites at positions +268 and +288 in the proximal promoter region. Binding of NF-AT to this region was detected only in tolerant CD4+ T cells, but not in fully activated CD4+ T cells by chromatin immunoprecipitation assays. Activation of these NF-AT sites was sufficient to induce TGF-beta1 promoter activity; however, additional signaling due to full Ag stimulation blocked NF-AT-mediated TGF-beta1 expression. This suppression of the TGF-beta1 promoter is mediated by the -1079 to -406 region, in which deletion of a GATA-binding motif at position -821 abrogates NF-AT-mediated activation of the TGF-beta1 promoter. Therefore, TGF-beta1 expression in T cells is controlled by multiple regulatory factors that have distinct functions in response to partial or full TCR activation.

In the immune system, TGF-beta1 exerts two major functions, anti-inflammatory and immuno-suppressive effects. This work aims to investigate the molecular mechanisms involved in the regulation of the TGF-beta1 gene expression in CD4(+) T cells. The TGF-beta1 gene expresses three transcripts of 2.5, 1.9, and 1.4kb. The 1.9kb mRNA which has the highest translation activity was the major transcript. The relationship between T cell receptor (TCR) stimulation and the expression of the gene was investigated. TCR stimulation with a low dose of antigen peptide enhanced the gene expression, whereas a higher dose suppressed the expression. TCR stimulation activates PKC/MAPK and Ca(2+) signaling pathways. PMA increased the gene expression, whereas ionomycin decreased the gene expression, markedly. The results indicate that Ca(2+) signaling down-regulates TGF-beta1 gene expression. The molecular regulation of TGF-beta1 gene expression is unique when comparing to other cytokine genes which are generally activated by Ca(2+) signaling.

Au/CeO2 and Ir/CeO2 catalysts were observed by a transmission electron microscope in order to investigate the nano-structures of Au and Ir particles and CeO2 grains and the interface structure between metallic particles and CeO2. An annular dark field scanning transmission electron microscope (ADF-STEM) and an energy dispersive X-ray spectroscopy (EDS) revealed that the metallic particles smaller than 2 nm in diameter are highly dispersed on CeO2 supports in both catalysts. For model samples of larger CeO2 particles with flat facets of low-index surfaces, high resolution transmission electron microscopy observations of Au/CeO2 and Ir/CeO2 interfaces were made and the epitaxial relationship between Au and CeO2, (111)[110]Au//(111)[110]CeO2 has been found for the first time.

In this study, we investigated the relationship between the expression levels of self-antigen and the function of self-reactive T cells in the periphery. To this end, we used two rat insulin promoter-ovalbumin (RIP-OVA) transgenic mice (RIP-OVA(high), RIP-OVA(low)) in which was produced only in pancreatic beta-islet cells. The OVA-producing transgenic mice were crossed to DO.11.10 (DO) mice expressing a T cell antigen receptor specific for OVA(323-339). The responsiveness of peripheral CD4(+) T cells in the double transgenic mice was examined. We demonstrated that hyporesponsive but highly IL-10-producing T cells were developed in DO x OVA(high) mice only, not in DO x OVA(low) mice. These IL-10-producing T cells exhibited regulatory activity both in in vitro and in vivo experiments. Moreover, these IL-10-producing regulatory T (Tr) cells expressed high levels of inducible costimulator (ICOS) before in vitro stimulation. Blockade of ICOS-signaling inhibited the production of IL-10 and abrogated the inhibitory function of these Tr cells. Thus, these results suggested that the development of IL-10-producing Tr cells depends on the expression levels of self-antigen in vivo and that ICOS signal plays a critical role in immune regulation by IL-10-producing Tr cells in self-tolerance.

The TCR alpha/beta chains recognize antigen peptides bound to the groove of the MHC class II molecule. The crystal structure analyses of the TCR/peptide/MHC class II complexes have revealed that the Valpha chains play a significant role in antigen recognition. However, molecular details which amino acid residues of the Valpha chain are able to contribute to fine antigen specificity are not clearly understood. Previously, we have classified a panel of T hybrids specific for insulin isotypes from different species of animals into four groups based on response profiles to these antigens. In particular, the group III (pork insulin > or = beef insulin hierarchy of responsiveness) and IV (pork insulin >> beef insulin hierarchy of responsiveness) T hybrids are interesting, since these TCR alpha/beta chains with marked different antigen specificities demonstrate identical gene usages and very similar sequences. To specifically address the molecular requirements for insulin recognition by TCR, the TCR alpha and beta chain genes from these group III and IV T hybrids were transfected into 58 alpha-beta- T hybrid. The experiments suggested that CDR3alpha dictates the fine antigen specificity. Then, we have introduced a series of mutations into position 95 of CDR3alpha. The mutation experiments clearly indicated that position 95alpha determines the antigen specificity of the group III and IV T hybrids.

The innate immune system has evolved as the first line of defense against invading microorganisms. The recent discovery of the toll-like receptors(TLRs) has rapidly expanded our knowledge of molecular events that initiate host-pathogen interactions. The TLRs, which are expressed on the surface of cells, involved in innate immune recognition, including macrophages and dendritic cells, have a crucial role in the detection of microbial infection. Signals initiated by the interaction of TLRs with pathogen-associated molecular patterns (PAMPs) induce activation of the inflammatory and antimicrobial innate immune response. Ten members of the TLR family have been identified, and they appear to recognize PAMPs, including lipopolysaccharide, peptidoglycan, and bacterial DNA. There has been considerable interest in how adaptive immune responses are controlled by the innate immune system. Recent studies have suggested that TLRs may control the induction of Th1 responses and that a separate system of recognition regulates the Th2 response. Thus TLR signaling represents a key component in the innate immune response to microbial infection.

The qualitative nature of an immune response raised against infectious pathogens depends upon the phenotypes of T(h) cell subsets, which secrete distinct types of cytokines. Genetic background is known to greatly influence the nature of the T(h) cell response. However, the precise nature of this influence still remains unclear. In the present study, we demonstrate that CD62L(+), CD44(low) and CD4(+) naive T cells from BALB/c mice are capable of producing significant amounts of IL-4, while naive T cells from B10.D2 mice exhibit no IL-4 production. The addition of exogenous IL-4 into the B10.D2 induction culture recovered T(h)2 development, thereby indicating that the potential of naive T cells to secrete IL-4 at primary activation is likely to substantially influence development of T(h)2. Regulation of the IL-4 gene in naive T cells differs from that in cells committed towards becoming T(h)2 cells, based on the observation that naive T cells from STAT6-deficient mice having a BALB/c background produce detectable amounts of IL-4. The IL-4 promoter region was found to be equally histone acetylated in both BALB/c and B10.D2 naive T cells by primary TCR activation. Interestingly, the expression levels of transcription factors NF-AT and GATA-3, which regulate promoter activity, differ between BALB/c and B10.D2 cells. These results suggest that the differences in expression level between the two transcriptional factors may affect the potential of naive T cells to secrete IL-4, which may subsequently influence the development of T(h) cell phenotypes.

Transforming growth factor-beta1 (TGF-beta1) is an inhibitory cytokine increasingly recognized as a key factor for immuno-regulation. The function of IL-4 in the regulation of TGF-beta1 production from T cells has been reported previously; however, the precise molecular mechanism still remains to be elucidated. For a better understanding of the mechanism involved in regulation, we have investigated a relationship between the STAT6-dependent pathway and TGF-beta1 production from naïve T cells. TCR crosslinking initiates TGF-beta1 production in CD4(+) T cells, and IL-4-mediated signaling enhances the TGF-beta1 production from naïve CD4(+) T cells. The IL-4-mediated up-regulation of TGF-beta1 production from naïve CD4(+) T cells is elicited in STAT6-deficient (STAT6 KO) mice, but not in IL-4 receptor-deficient (IL-4R KO) mice. These results clearly demonstrate that a STAT6-independent pathway is working in IL-4-mediated enhancement of TGF-beta1 production from naïve CD4(+) T cells. Moreover, the addition of IL-4 showed no additive effect on TGF-beta1 promoter-mediated transcription stimulated by TCR. Therefore, we hypothesize that the IL-4-mediated signaling does not work directly on the transcription of the TGF-beta1 gene, but rather regulates the expansion of TGF-beta1-secreting T cells.

We analyzed the cytolytic activity of intraepithelial T cells (IEL) isolated from the small intestines of 2- to 3-month-old mutant mice rendered deficient in different gene(s) in which the number of IEL expressing either T cell receptor (TCR)-alpha beta (alpha beta-IEL) or TCR-gamma delta (gamma delta-IEL) were absent or markedly diminished. When compared with wild-type littermates, cytolytic activity of gamma delta-IEL was sharply attenuated in TCR-beta mutant mice but remained unaltered in TCR-alpha mutant mice in which a minor population of dull TCR-beta+ (betadim)-IEL was also present. Cytolytic activity of gamma delta-IEL was maintained in mice doubly homozygous for beta2-microglobulin and transporter associated with antigen processing 1 gene mutations in which a conspicuous decrease was noted in absolute numbers of alpha beta-IEL. In contrast, both TCR-delta and IL-7 receptor-alpha gene mutations that lead to lack of gamma delta-IEL generation did not affect the development or cytolytic activity of the remaining alpha beta-IEL. The anti-CD3 and anti-TCR-gamma delta mAb-induced IFN-gamma production of gamma delta-IEL showed the same TCR-alpha and TCR-beta mutation-dependent variability. These results indicate that cytolytic and IFN-gamma-producing activities of gamma delta T cells in mouse intestinal epithelium are TCR-beta-chain-dependent.

Direct activation of human cytotoxic T lymphocytes (CTL) by interleukin (IL)-18 was observed in a system in which CTL effective against autologous tumor cells were generated. Peripheral blood mononuclear cells (PBMC) from tumor-bearing patients, after removal of natural killer (NK) cells, were cultured in a medium containing IL-1, -2, -4, and -6, with or without IL-18, and stimulated with autologous tumor cells. IL-18 increased the activity of the CTL and the proportion of autologous CD8+ T cells present after 28 days in the induction culture. When purified CD8+ T cells were cultured in the presence of IL-18 and IL-2 for 7 days, the CTL showed enhanced cytotoxic activity against autologous tumor cells. Moreover, a purified CD8+ T cell population, which did not exhibit any apparent cytotoxic activity against autologous tumor cells, displayed cytotoxic activity after 7-day incubation with IL-18. These results suggest that IL-18 may be useful to generate autologous CTL in humans and may thereby contribute to adoptive immunotherapy for tumors.

Modulation of CD8(+) T-cell responses specific for an exogenous antigen by epitope variants would be advantageous to develop a novel means of antigen-specific immune regulation. We have analyzed CD8(+) T-cell responses to single amino acid-substituted variants of a peptide corresponding to residues 142-149 (p142-149; LAYFYPEL) of alphas1-casein, a major milk allergen, which is a dominant determinant restricted by H-2Kb. An analog peptide L142I with a substitution of Ile for Leu at the nonanchor N-terminal residue induced more IFN-gamma secretion than p142-149 from specific CD8(+) T cells. Furthermore, L142I could prime CD8(+) T cells more efficiently in vivo, and these L142I-primed cells secreted more IFN-gamma than p142-149-primed CD8(+) T cells upon stimulation with p142-149 in vitro. These findings are mainly explained by the greater ability of L142I to form stable Kb-peptide complexes. These findings indicate that appropriate analog peptides may be useful as efficient inducers of CD8(+) T cells which recognize the parent peptide and secrete IFN-gamma, a potent inhibitor of Th2-dependent events, including IgE production., (Copyright 1998 Academic Press.)

The CD8+ T cell clone 5F1 produces interleukin 10 (IL-10) and interferon gamma(IFN-gamma) in response to stimulation with a peptide corresponding to region 142-149 of bovine alpha(s1)-casein (p142-149). Ninety analog peptides derived from p142-149 with single amino acid substitutions of putative T cell receptor contact residues were prepared to examine whether production of IL-10 and IFN-gamma by 5F1 can be altered by stimulation with these peptides. We found that some peptides triggered only IL-10 production whereas others induced production of IFN-gamma alone or both of these cytokines. Peptides inducing IFN-gamma production triggered both cytotoxicity and a proliferative response, whereas peptides inducing production of IL-10 but not IFN-gamma triggered neither of these responses. Our results clearly demonstrate that the signaling pathway required for IL-10 production in CD8+ T cells differs from that required for IFN-gamma production. The distinct cellular signals for IL-10 production appear to be independent of those for cytotoxicity and the proliferative response of CD8+ T cells.

Feeding of a whole casein diet, which abolished the α(s1)-casein-specific proliferation and IFN-γ productivity of CD(4+) T cells, did not affect the proliferative response of CD8(+) T cells with regard to the antigen dose response, cell dose response, kinetics of the proliferation and epitope specificity, as well as IFN-γ production. To assess the characteristics of the CD8(+) T cells, we established α(s1)-casein-specific CD8(+) T cell clones from both casein-fed and control mice. The established clones produced different amount of IFN-γ and IL-10, and one clone derived from the casein-fed mice produced a remarkable amount of IL-10. The clones from casein-fed mice produced considerable amounts of TGF-β, while those from control mice produced only small amounts. The possible role of CD8(+) T cells in oral tolerance is discussed.

A 62-year-old man with complaints of severe chest pain came to our hospital. An emergency coronary angiography was performed and he was diagnosed as having acute myocardial infarction. Due to severe triple vessels disease he was referred to the department of Cardiovascular Surgery to undergo emergency coronary artery bypass grafting. In the coronary care unit, sudden hematoemesis due to hemorrhagic gastric ulcer occurred, however, just when he was going to be transferred to the operation room. Because the gastric bleeding was thought to be serious under extracorporeal circulation, which was indispensable for coronary artery bypass grafting, gastrotomy with suturing ulcer was performed prior to median sternotomy with use of intraaortic balloon pumping. Severe infection was not complicated. His postoperative course was uneventful.

Elephant trunk prosthesis was devised for treatment of multiple aortic aneurysm. But it has applied to type A aortic dissection. Because residual false lumen often dilates gradually and come to have the risk of rupture. Two patients who were diagnosed as type A aortic dissection were performed total aortic arch replacement with Elephant trunk prosthesis on distal anastmosis. Postoperative diagnostic images showed that residual false lumen of proximal descending aorta were thrombosed. Now it is not necessary to perform next extensive aortic replacement. Complication which is threatened in using Elephant trunk prosthesis, paraplegia, thromboembolism, kinking of prosthesis could have been avoided by setting suitable length and diameter of the prosthesis.

A 58-year-old man, who had been submitted to an indication of mitral valvuloplasty (MVP) because of severe mitral regurgitation, was diagnosed as idiopathic thrombocytopenic purpura (ITP). In order to diminish the peri-operative blood loss, splenectomy and high-dose bolus administration of gamma-globulin (400 mg/kg/day) were performed at the time of two weeks and during last five days respectively, prior to MVP surgery. In early post-operative stage, anticoagulant therapy was held down considering ITP, and we were not troubled with bleeding throughout the peri-operative period. On the fourteenth post-operative day, however, mural thrombi in the left atrium were pointed out by transesophageal echocardiography (TEE). Then anticoagulant therapy was reinforced by increasing the warfarin dose. When TEE was restudied on 36th, post-operative day, mural thrombi had almost disappeared. Although it is commonly known that mitral valvuloplasty has low risk of thrombosis and less necessity of anticoagulation, hyper coagulability may be feasible in the early post-operative period of our case whose ITP is meticulously treated prior to surgery. Suitable anticoagulation should have been performed regardless of ITP immediately after MVP.

alpha s1-Casein-specific CD8+ T cell clones expressed the interleukin (IL)-4 receptor, although they did not secrete detectable IL-4. We found that IL-4 significantly enhanced the secretion of interferon (IFN)-gamma by these CD8+ T cell clones. IL-4 also enhanced the secretion of IFN-gamma induced by stimulating the immobilized anti-CD3 antibodies of polyclonal CD8+ T cells which had been isolated from lymph nodes and were stimulated in vitro with the immobilized anti-CD3 antibody and IL-2. In addition, IL-4 added at the time of this first in vitro stimulation induced strong IFN-gamma productivity, as well as IL-4 and IL-10 productivity, which were detectable upon restimulation of these cells. Results are discussed in relation to the inhibitory effects of IFN-gamma production on IL-4-producing cells.

Intestinal intraepithelial T cells (IELs) expressing either gammadelta TCR or alphabeta TCR have been proposed to play an important role in the regulation of intestinal epithelia by producing cytokines that directly influence the adjoining intestinal epithelial cell (IEC) functions. To illuminate this issue, we utilized TCR mutant mice to obtain gammadelta IELs, alphabeta IELs and mixed gammadelta and alphabeta IELs from corresponding alphabeta T-cell-deficient (beta-/-), gammadelta T-cell-deficient (delta-/-) and wild-type (WT) littermate mice. The production of IFN-gamma by these IELs as well as the mRNA for IFN-gamma, TGF-alpha, TGF-beta1, TNF-alpha and TNF-beta in these IELs, in conjunction with the effect of produced cytokines on the expression of class II MHC molecules by the in vitro cell line IEC-6, were investigated. IFN-gamma and TNF-alpha [corrected] specific mRNA were detectable in all freshly isolated gammadelta, alphabeta and WT IELs. In addition to the IFN-gamma and TNF-alpha [corrected] mRNA, alphabeta and WT IELs that had been activated in culture plates coated with anti-CD3 mAb contained mRNA for TGF-beta1 and TNF-beta proteins. In the cultured gammadelta IELs, however, the signals for IFN-gamma and TNF-alpha [corrected] transcripts were weak, and mRNA for the latter two cytokines was almost undetectable. Supernatants from in vitro culturing of alphabeta and WT IELs but not gammadelta IELs induced class II MHC gene expression in IEC-6, whereas, in the presence of anti-IFN-gamma mAb, the same culture supernatants failed to do so. In fact, the concentration of IFN-gamma in supernatants from alphabeta and WT IEL cultures was ten- to twentyfold higher than that in the supernatant from the gammadelta IEL culture. Finally, TGF-alpha specific mRNA was not detectable in the gammadelta and alphabeta IELs even after in vitro activation. These results indicate that alphabeta IELs are superior to gammadelta IELs in the ability to produce IFN-gamma, TGF-beta1, TNF-alpha [corrected] and TNF-beta through TCR crosslinking primary in vitro stimulation.

CD8+ T cell clones produced both interleukin 10 (IL-10) and interferon-gamma (IFN-gamma) when these cells were stimulated with a T-cell-specific mitogen, concanavalin A (Con A). One of these CD8+ T cell clones, 13G2, secreted IFN-gamma at similar levels with calcium ionophore, A23187, as well as by Con A, but IL-10 production by A23187 was less than by Con A. On the other hand, N6,O2-dibutyryl cAMP enhanced the production of IL-10 but not IFN-gamma when the low doses of Con A or A23187 coexisted. In a T cell clone, the production of these two cytokines required different signal transductions. These results indicate that a T cell clone can produce diverse cytokines depending on the surrounding condition.

All CD8+ T cell clones used in this study secreted IL-10, and their proliferation was inhibited by exogenous IL-10. This study addresses the question of whether IL-10 produced by responding T cell clones would inhibit proliferation of the secreting T cells themselves. Anti-IL-10 antibodies enhanced the proliferative response of the CD8+ T cell clones, the enhancing effect appearing in the late period of proliferation. However, the proliferation of both CD4+ Th1 and Th2 clones was not affected by anti-IL-10 throughout the culture. In addition to that of the cloned T cells, the proliferative response of a primary culture of CD8+ T cells was enhanced by the anti-IL-10 antibody. This is the first report on a lymphokine which has an autoregulatory role in inhibiting T cell proliferation.

Highly purified CD8+ T cells were stimulated repeatedly by syngeneic irradiated spleen cells. From separate cloning experiments, we succeeded in isolating two CD8+ clones, 4B4 and D2, which proliferated in response to autologous antigen-presenting cells (APC) completely in the absence of fetal calf serum. A T cell proliferation assay, using congenic strain of mice, indicates that both autoreactive clones were restricted to self-Db molecules. Our study is the first report of establishing murine autoreactive CD8+ clones restricted to self MHC class I molecules. To assess the immune suppressive activity of each autoreactive clone, we measured the production of IL-10 and interferon-gamma, which have specific immune suppressive activity toward type 1 helper T cell (Th1) proliferation and IgE synthesis, respectively. In response to autologous APC, both D2 and 4B4 produced considerable amounts of interferon-gamma and a low but significant level of IL-10. Each supernatant of D2 and 4B4 significantly suppressed IgE synthesis. These results strongly suggest the existence of CD8+ autoreactive T cells with immune suppressive activity.

Endoscopic laser treatment was initially applied for gastrointestinal bleeding, but has been actively extended, especially in Japan, to the curative treatment of early upper gastrointestinal cancers. We have treated 10 cases of early gastric cancer and 1 case of early esophageal cancer by Nd-YAG laser radiation, and 2 cases of early gastric cancer by photochemical therapy (PCT) with argon laser + hematoporphyrin derivative. Also, 62 cases of advanced cancer were treated, 10 of the esophagus and 52 of the stomach, for bleeding (18 cases) or stenosis (34 cases). The cases were nonresectable or they were patients who refused surgery. Satisfactory results were obtained by treatment with YAG laser, but have not yet been obtained with PCT. In order to find indications for the possible extension of endoscopic laser therapy to operable cases of early gastric cancer, we studied lymph node metastases in 200 cases of early gastric cancer surgically treated by us. It was found that early gastric cancers (both mucosal and submucosal) measuring less than 2 cm in diameter, of type I, IIa, and IIc (without ulcer scar), had no lymph node metastases and such cases can be treated by local therapy--such as endoscopic laser therapy. In palliative endoscopic laser therapy for complications of advanced gastrointestinal cancers, there are no major problems with active performance. We obtained a high (90%) hemostatic rate in bleeding cases of upper gastrointestinal cancer and a satisfactory (65%) rate of dilating effect in cases of cancerous stenosis at the esophagus and cardia.(ABSTRACT TRUNCATED AT 250 WORDS)